e10vq

FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
OF THE SECURITIES EXCHANGE ACT OF 1934


For quarterly period ended March 31, 2006		Commission File Number 0-22962

HUMAN GENOME SCIENCES, INC.

(Exact name of registrant)


Delaware (State of organization)		22-3178468 (I.R.S. Employer Identification Number)

14200 Shady Grove Road, Rockville, Maryland 20850-7464
(Address of principal executive offices and zip code)

(301) 309-8504
(Registrant’s telephone Number)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.
Yes þ No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer or a non-accelerated filer. See definition of “accelerated filer” and “large accelerated filer” in Rule 12b-2 of the Exchange Act.


Large accelerated filer þ		Accelerated filer o		Non-accelerated filer o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).
Yes o No þ

The number of shares of the registrant’s common stock outstanding on March 31, 2006 was 131,428,636.

PART I. FINANCIAL INFORMATION

HUMAN GENOME SCIENCES, INC.
CONSOLIDATED STATEMENTS OF OPERATIONS


	Three months ended
	March 31,
	2006			2005
	(dollars in thousands, except
	share and per share amounts)
Revenue — research and development contracts	$	6,840		$	1,105


Costs and expenses:
Research and development		58,407			54,199
General and administrative		13,391			9,428


Total costs and expenses		71,798			63,627


Income (loss) from operations		(64,958	)		(62,522	)

Investment income		5,117			6,242
Interest expense		(2,298	)		(3,302	)

Income (loss) before taxes		(62,139	)		(59,582	)
Provision for income taxes		—			—


Net income (loss)	$	(62,139	)	$	(59,582	)


Basic and diluted net income (loss) per share	$	(0.47	)	$	(0.46	)


Weighted average shares outstanding, basic and diluted		131,221,924			130,609,985

The accompanying Notes to Consolidated Financial Statements are an integral part hereof. Net income (loss) for the three months ended March 31, 2006 included stock-based compensation expense under FASB Statement No. 123(R), “Share-Based Payment” (“SFAS 123(R)”) of $6,726 related to employee stock options representing $4,308 in Research and development and $2,418 in General and administration. There was no stock-based compensation expense related to employee stock options under FASB Statement No. 123, “Accounting for Stock-Based Compensation” (“SFAS 123”) included in net income (loss) for the three months ended March 31, 2005 because the Company did not adopt the fair value recognition provisions of SFAS 123, but rather used the alternative intrinsic value method.

HUMAN GENOME SCIENCES, INC.
CONSOLIDATED BALANCE SHEETS


	March 31,			December 31,
	2006			2005
	(dollars in thousands, except
	share and per share amounts)
Assets
Current assets:
Cash and cash equivalents	$	7,414		$	12,268
Short-term investments		235,911			169,961
Prepaid expenses and other current assets		10,387			6,088

Total current assets		253,712			188,317

Marketable securities		119,825			243,820
Long-term equity investments		18,858			18,493
Property, plant and equipment (net of accumulated depreciation and amortization)		303,595			304,809
Restricted investments		217,247			220,171
Other assets		20,438			21,436

TOTAL ASSETS	$	933,675		$	997,046


Liabilities and Stockholders’ Equity
Current liabilities:
Current portion of long-term debt	$	3,120		$	3,120
Current portion of capital lease obligation		231			316
Accounts payable and accrued expenses		32,858			38,334
Accrued payroll and related taxes		11,574			14,330
Deferred revenues		3,359			3,335

Total current liabilities		51,142			59,435

Long-term debt, net of current portion		510,000			510,000
Deferred revenues, net of current portion		5,073			5,900
Other liabilities		4,422			4,745

Total liabilities		570,637			580,080


Stockholders’ equity:
Preferred stock		—			—
Common stock		1,313			1,310
Additional paid-in capital		1,795,571			1,786,549
Accumulated other comprehensive loss		(2,499	)		(1,685	)
Accumulated deficit		(1,431,347	)		(1,369,208	)

Total stockholders’ equity		363,038			416,966

TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$	933,675		$	997,046

The accompanying Notes to Consolidated Financial Statements are an integral part hereof.

HUMAN GENOME SCIENCES, INC.
CONSOLIDATED STATEMENTS OF CASH FLOWS


	Three months ended March 31,
	2006			2005
	(dollars in thousands)
Cash flows from operating activities:
Net income (loss)	$	(62,139	)	$	(59,582	)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Accrued interest on short-term investments and marketable securities		1,273			(490	)
Depreciation and amortization		4,533			4,919
(Gain) loss due to disposal of property, plant and equipment		(83	)		320
Stock-based compensation expense related to employee stock options		6,726			—
Stock-based compensation expense related to nonvested stock		136			—
Loss on sale of investments and marketable securities		164			918
Loss on sale of restricted investments		14			42
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		(4,299	)		1,303
Other assets		3,079			3,756
Accounts payable and accrued expenses		(535	)		(2,544	)
Accrued restructuring charges		(1,256	)		—
Accrued payroll and related taxes		(2,756	)		1,937
Deferred revenues		(803	)		672
Other liabilities		(2,962	)		(3,580	)

Net cash provided by (used in) operating activities		(58,908	)		(52,329	)

Cash flows from investing activities:
Capital expenditures — property, plant and equipment		(5,098	)		(33,354	)
Capitalized interest		(1,261	)		(1,366	)
Purchase of short-term investments and marketable securities		(44,266	)		(58,133	)
Proceeds from sale and maturities of short-term investments and marketable securities		89,280			142,131

Net cash provided by investing activities		38,655			49,278

Cash flows from financing activities:
Purchase of restricted short-term investments and marketable securities		(38,788	)		(28,811	)
Proceeds from sale and maturities of restricted investments		52,110			27,154
Proceeds from issuance of common stock (net of expense)		2,162			811
Payments on capital lease		(85	)		(81	)

Net cash provided by (used in) financing activities		15,399			(927	)

Net (decrease) increase in cash and cash equivalents		(4,854	)		(3,978	)
Cash and cash equivalents — beginning of year		12,268			24,075

Cash and cash equivalents — end of year	$	7,414		$	20,097

Supplemental disclosures of cash flow information:
Cash paid during the period for:
Interest	$	2,763		$	5,132
Income taxes	$	—		$	—

The accompanying Notes to Consolidated Financial Statements are an integral part hereof.

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 1. Interim Financial Statements

The accompanying unaudited consolidated financial statements of Human Genome Sciences, Inc. (the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information. In the opinion of the Company’s management, the consolidated financial statements reflect all adjustments necessary to present fairly the results of operations for the three months ended March 31, 2006 and 2005, the Company’s financial position at March 31, 2006, and the cash flows for the three months ended March 31, 2006 and 2005. These adjustments are of a normal recurring nature.

Certain notes and other information have been condensed or omitted from the interim consolidated financial statements presented in this Quarterly Report on Form 10-Q. Therefore, these financial statements should be read in conjunction with the Company’s 2005 Annual Report on Form 10-K.

The results of operations for the three months ended March 31, 2006 are not necessarily indicative of future financial results.

Note 2. Stock-Based Compensation

As of March 31, 2006, the Company has two stock-based compensation plans, which are described below. The compensation cost that has been recorded as expense for those plans was $6,862, comprised of $6,726 related to stock options and $136 related to nonvested stock, and $0 for the three months ended March 31, 2006 and 2005, respectively. No income tax benefit was recognized in the income statement for stock-based compensation for the three months ended March 31, 2006 and 2005 as realization of such benefits was not more likely than not.

Stock Incentive Plan

The Company has a stock incentive plan under which options to purchase new shares of the Company’s common stock may be granted to employees, consultants and directors at a price no less than the fair market value on the date of grant. The plan also provides for awards in the form of stock appreciation rights, restricted or unrestricted stock awards, stock-equivalent units or performance-based stock awards. The Company issues both qualified and non-qualified options under the stock incentive plan.

In 2000, the Company adopted the 2000 Stock Incentive Plan (the “2000 Plan”) for the granting of options to purchase shares of common stock to officers, employees, directors, consultants and non-employee directors. The Company’s prior plans were merged into the 2000 Plan. The exercise price of options granted under the plan may not be less than the market price on the date of grant. The vesting period of the options is determined by the Board of Directors and is generally four years. Upon acquisition by a person, or group of persons, of more than 50% of the Company’s outstanding common stock, granted options shall immediately vest in full and be exercisable. The Company recognizes compensation expense for an award with only service conditions that has a graded vesting schedule on a straight-line basis over the requisite service period for the entire award. All options expire after ten years or earlier from the date of grant.

At March 31, 2006, the total authorized number of shares under all plans was 53,228,746. Options available for future grant were 7,342,291 as of March 31, 2006.

Prior to January 1, 2006, the Company accounted for its stock-based compensation plans under the recognition and measurement provisions of Accounting Principles Board Opinion No. 25, “Accounting for Stock Issued to Employees” (“APB No. 25”), and related Interpretations, as permitted by Financial Accounting Standards Board (“FASB”) Statement No. 123, “Accounting for Stock-Based Compensation” (“SFAS 123”).

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 2. Stock-Based Compensation (continued)

Effective January 1, 2006, the Company adopted the fair value recognition provisions of FASB Statement No. 123(R), “Share-Based Payment” (“SFAS 123(R)”), using the modified-prospective method. Under the modified-prospective method, compensation cost recognized in the first quarter of fiscal 2006 includes: (a) compensation cost for those stock-based awards vesting during the three months ended March 31, 2006 that were granted prior to January 1, 2006, based on the grant date fair value estimated in accordance with the fair value measurement provisions of SFAS 123, and (b) compensation cost for all stock-based awards vesting during the three months ended March 31, 2006 that were granted on or after January 1, 2006, based on the grant-date fair value estimated in accordance with the provisions of SFAS 123(R). Results for prior periods have not been restated. The fair value of each option grant is estimated on the date of grant using the Black-Scholes-Merton option-pricing model.

The Company accounts for equity instruments issued to non-employees in accordance with Emerging Issues Task Force 96-18, “Accounting for Equity Instruments that are Issued to Other Than Employees for Acquiring, or in conjunction with Selling, Goods, or Services”.

Common stock equity award activity is as follows for the three months ended March 31, 2006:


						Weighted-
						Average
				Weighted-		Remaining
				Average		Contractual		Aggregate
				Exercise		Term		Intrinsic
	Shares			Price		(years)		Value⁽¹⁾
Outstanding at January 1, 2006		29,301,035		$	18.90
Granted		3,457,860			10.90
Exercised		(268,838	)		8.05			$	899
Forfeited or expired		(414,843	)		19.28

Outstanding at March 31, 2006		32,075,214			18.13		5.8		18,348

Vested or expected to vest at March 31, 2006		30,363,324			18.49		5.1		18,047

Exercisable at March 31, 2006		20,662,615			21.69		4.3		16,338

⁽¹⁾ Aggregate intrinsic value represents only the value for those options in which the exercise price of the option is less than the market value of the Company’s stock on March 31, 2006.

A summary of the status of the Company’s nonvested common stock as of March 31, 2006 and changes during the three months ended March 31, 2006, is presented below:


			Weighted-Average
Nonvested common stock	Shares		Grant-Date Fair Value
Outstanding at January 1, 2006		110,000	$	13.24
Granted		—		—
Vested		—		—
Forfeited		—		—

Outstanding at March 31, 2006		110,000		13.24

Vested at March 31, 2006		—		—

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 2. Stock-Based Compensation (continued)

The following table summarizes stock-based compensation expense related to employee stock options which was classified as follows:


						Three months ended March 31,
			2006							2005
	Expense					Expense		Expense				Expense
	including					excluding		including				excluding
	stock option		Stock option			stock option		stock option		Stock option		stock option
	compensation		compensation			compensation		compensation		compensation		compensation
Costs and expenses:
Research and development	$	58,407	$	(4,308	)		54,099	$	54,199	$	—	$	54,199
General and administrative		13,391		(2,418	)		10,973		9,428		—		9,428

Total	$	71,798	$	(6,726	)	$	65,072	$	63,627	$	—	$	63,627

For the three months ended March 31, 2006 and 2005, in conjunction with stock option exercises, the Company issued 268,838 and 97,559 shares of common stock, respectively. The Company received cash proceeds from the exercise of these stock options of approximately $2,162 and $811 for the three months ended March 31, 2006 and 2005, respectively.

The following table illustrates the effect on net income (loss) and net income (loss) per share if the Company had applied the fair value recognition provisions of SFAS 123 to stock-based employee compensation for the three month periods March 31, 2005. The reported and pro forma net income and net income per share for the three months ended March 31, 2006 are the same because stock-based compensation expense is calculated under the provisions of SFAS 123(R). The amounts for the three months ended March 31, 2006 are included in the table below only to provide net loss and net loss per share for a comparative presentation to the period of the previous year.


	Three months ended March 31,
	2006			2005
Net income (loss), as reported	$	(62,139	)	$	(59,582	)
Deduct: Total stock-based employee compensation expense determined under fair value based method for all awards, net of related tax effects		—			(8,801	)

Pro forma net income (loss)	$	(62,139	)	$	(68,383	)


Net income (loss) per share:
Basic and diluted — as reported	$	(0.47	)	$	(0.46	)
Basic and diluted — pro forma	$	(0.47	)	$	(0.52	)

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 2. Stock-Based Compensation (continued)

For the three months ended March 31, 2006 and 2005, diluted net income (loss) per share is the same as basic net income (loss) per share as the inclusion of outstanding stock options and convertible debt would be antidilutive.

The effect of applying SFAS No. 123(R) on the net loss and net loss per share for the three months ended March 31, 2006 as stated above, is not necessarily representative of the effects on reported net loss for future years due to, among other things, (1) the vesting period of the stock options and (2) the fair value of additional stock option grants in future years.

The following table summarizes the impact of stock-based and non vested stock compensation on cash flows for the three months ended March 31, 2006 and 2005.


	For the three months ended March 31,
	2006		2005
Cash flows from operations:
Stock-based compensation	$	6,726		—
Nonvested stock		136		—
Cash flows from financing activities:
Stock-based compensation		—		—
Nonvested stock		—		—

As of March 31, 2006, total compensation expense related to nonvested stock options not yet recognized was $60,280, which is expected to be recognized over the next 2.9 years on a weighted-average basis. There were 11,412,599 shares of nonvested stock options outstanding but not yet exercisable at March 31, 2006. The weighted average fair value of these shares of nonvested stock was $5.28 as of March 31, 2006.

The total intrinsic value of stock options exercised during the three months ended March 31, 2006 and 2005, was approximately $899 and $380, respectively. The total fair value of stock options which vested during the three months ended March 31, 2006 was approximately $6,726. The total fair value of stock options which vested during the three months ended March 31, 2005 was approximately $8,801. The weighted-average grant-date fair value of equity awards granted during the three months ended March 31, 2006 was $4.97. The weighted-average fair value of the equity awards granted during the three months ended March 31, 2006 was determined based on the Black-Scholes-Merton option-pricing model with the following assumptions:


		Three months ended
		March 31, 2006
Expected life:		4.87 – 5.05 years
Interest rate		4.33% – 4.55%
Volatility		38% – 45%
Dividend yield		0%

An explanation of the above assumptions is as follows:

Expected Life of Stock-based Awards — The expected life of stock-based awards is the period of time for which the stock-based award is expected to be outstanding.

HUMAN GENOME SCIENCES, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 2. Stock-Based Compensation (continued)

Interest Rate — The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant.

Volatility — Volatility is a measure of the amount by which a financial variable such as a share price has fluctuated (historical volatility) or is expected to fluctuate (implied volatility) during a period. The Company uses the implied volatility of its traded convertible notes as the sole basis for its expected volatility.

Dividend Yield — The Company has never declared or paid dividends and has no plans to do so in the foreseeable future.

Employee Stock Purchase Plan

During the second quarter of 2000, the Company’s stockholders approved the establishment of an Employee Stock Purchase Plan registering 500,000 shares of $0.01 par value common stock as available to this plan. Under the plan, eligible employees may purchase shares of common stock on certain dates and at certain prices as set forth in the plan. The first purchase period for the plan began January 1, 2001. Common stock reserved for future employee purchase under the plan aggregated 143,686 as of March 31, 2006. There are no other investment options for participants.

Note 3. Comprehensive Income (Loss)

SFAS No. 130, Reporting Comprehensive Income, requires unrealized gains or losses on the Company’s available-for-sale short-term securities, long-term investments and cumulative translation adjustment activity to be included in other comprehensive income.

During the three months ended March 31, 2006 and 2005, total comprehensive income (loss) amounted to:


	Three months ended
	March 31,
	2006			2005
Net income (loss)	$	(62,139	)	$	(59,582	)

Net unrealized gains (losses):
Short-term investments and marketable securities		1,042			(5,710	)
Long-term investments		365			(2,689	)
Restricted investments		(2,403	)		(1,797	)
Foreign currency translation		4			(4	)

Subtotal		(992	)		(10,200	)

Reclassification adjustments for losses realized in net loss		178			960

Total comprehensive income (loss)	$	(62,953	)	$	(68,822	)

The effect of income taxes on items in other comprehensive income is $0 for all periods presented.

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 3. Comprehensive Income (Loss) (continued)

Realized gains and losses on securities sold before maturity, which are included in the Company’s investment income for the three months ended March 31, 2006 and 2005, and their respective net proceeds were as follows:


	Three months ended
	March 31,
	2006			2005
Realized gains	$	67		$	62
Realized losses		(245	)		(1,022	)
Net proceeds on sale of investments prior to maturity		84,789			96,797

Note 4. Commitments and Other Matters

The Company’s primary research and development and administrative facility, located on the Traville site in Rockville, Maryland, is owned by Wachovia Development Corporation (“WDC”). WDC, a wholly-owned subsidiary of Wachovia Corporation, is primarily engaged in real estate finance, development and leasing activities. The total financed cost of the Traville lease facility is $200,000. The Company’s rent obligation approximates the lessor’s debt service costs plus a return on the lessor’s equity investment. The Company’s rent obligation under the Traville lease is floating and is based primarily on short-term commercial paper, but the lessor can lock in a fixed interest rate at any time at the Company’s request. The floating rate was approximately 4.6% as of March 31, 2006.

The Company’s restricted investments with respect to the Traville lease and leases for the existing process development and manufacturing facility will serve as collateral for the duration of the leases. The Company is required to restrict investments equal to 102% of the full amount of the $200,000 financed project cost for the Traville lease, or $204,000. In addition, the Company is also required to maintain up to a maximum of $15,000 in restricted investments with respect to the process development and manufacturing facility leases. The Company’s restricted investments were $217,247 and $220,171 as of March 31, 2006 and December 31, 2005, respectively.

Under the Traville lease agreement, which the Company has accounted for as an operating lease, the Company has the option to purchase the property, during or at the end of the lease terms, for an aggregate amount of $200,000. Alternatively, the Company can cause the property to be sold to third parties. The Company has a residual value guarantee of 87.75% of the total financed cost at lease termination. In the event of default, the Company is responsible for 100% of the total financed cost of the project. Because the lessor is responsible for servicing and repaying the debt financings to various parties, the Company has made the residual value guarantee to the lessor. In the event the lessor defaults to the lender, the Company has the right to cure the default or exercise its option to acquire the property. At any time during the lease term, the Company has the option to purchase legal and/or beneficial interest in the project for 100% of the lease balance plus any unpaid indemnity amounts. As of March 31, 2006, the Company’s residual value guarantee for the Traville lease had reached the full maximum amount of $175,500.

In connection with the Traville lease, the Company must maintain minimum levels of unrestricted cash, cash equivalents and marketable securities and certain debt ratios.

See Note 8, Subsequent Event, for additional information.

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 5. Charge for Restructuring

During the first quarter of 2004, the Company announced plans to sharpen its focus on its most promising drug candidates and reduced staff, streamlined operations and consolidated facilities. The Company may continue to evaluate other facility consolidation alternatives during 2006.

The Company had a lease agreement for a research facility located at 9800 Medical Center Drive, near the Company’s Traville facility in Rockville, Maryland (the “9800 MCD lease”). In December 2004, the Company exited its seven-year lease associated with this facility. The Company’s exit accrual for this facility was $4,801 and $5,937 as of March 31, 2006 and December 31, 2005, respectively. The Company will review the adequacy of its estimated exit accrual on an ongoing basis.

The following table summarizes the activity related to the liability for restructuring costs as of March 31, 2006:


			Former CEO
	Severance		Related
	and		Benefits			Facilities
	Benefits		Charges			Related			Total
Balance as of January 1, 2006	$	20	$	442		$	5,937		$	6,399
Cash paid		—		(120	)		(1,136	)		(1,256	)
Non-cash		—		—			—			—

Balance as of March 31, 2006	$	20	$	322		$	4,801		$	5,143

The liability for restructuring costs of $5,143 and $6,399 as of March 31, 2006 and December 31, 2005, respectively, was shown within accounts payable and accrued expenses on the consolidated balance sheets.

Note 6. Fair Value of Financial Instruments

The carrying amounts for the Company’s investments reflected in the consolidated balance sheets at March 31, 2006 and December 31, 2005 approximate their respective fair values. The fair value of the Company’s investments is based on quoted market prices.

The carrying value of the Company’s debt was approximately $513,000 as of both March 31, 2006 and December 31, 2005. The fair value of the Company’s long-term debt is based primarily on quoted market prices. The quoted market prices of the Company’s convertible debt increased to approximately $467,000 as of March 31, 2006 from $408,000 as of December 31, 2005.

Note 7. Related Parties

The Company’s equity investments in Cambridge Antibody Technology Ltd. (“CAT”) and Corautus Genetics Inc. (“Corautus”) make them related parties with the Company. Effective with the sale of the Company’s investment in Transgene, S.A. (“Transgene”) in 2005, Transgene is no longer a related party. While deemed a related party, the Company recognized revenue of $642 for the three months ended March 31, 2005 under a 1998 collaboration agreement with Transgene. For both of the three months ended March 31, 2006 and 2005, the Company expensed $300 for support costs paid to CAT in connection with a collaboration agreement. The Company had no other material related party transactions in these periods.

HUMAN GENOME SCIENCES, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
For the Quarter Ended March 31, 2006
(dollars in thousands, except share and per share data)

Note 8 — Subsequent Event

Commitments and Contingencies — Facilities- Traville and Large-Scale Manufacturing

In May 2006, the Company entered into a Purchase and Sale agreement with BioMed Realty, LLP (“BioMed”) to either sell or cause to be sold the Traville facility, the Traville land and the Large-Scale Manufacturing facility (“LSM”) and concurrently entered into long-term lease agreements with BioMed for the two facilities.

With respect to Traville, the Company is exercising its option under its current lease with Wachovia Development Corporation (“WDC”) to cause the property to be sold by WDC to BioMed. In addition, the Company is selling its land associated with the Traville facility as well as the adjoining undeveloped land on the site. At closing, BioMed will pay WDC $200,000 to purchase the Traville facility, at which time WDC will terminate its lease with the Company and release the Company’s restricted investments of approximately $204,500 that served as collateral under the lease. In addition, the Company will receive approximately $25,000 in cash in consideration for all of the land and improvements associated with the Traville site. The Company expects to record a loss of approximately $4,700 associated with Traville-related assets, excluding transaction costs of approximately $2,000.

For Traville, the Company is entering into a twenty year lease, with a buy-out option after ten years, with BioMed with initial annual rent of approximately $19,750. Aggregate rental payments over the twenty year period are approximately $480,000, including an expected annual escalation of 2%. The Company will be required to restrict investments of approximately $22,000 to serve as a security deposit under this lease. As a result of entering into this lease, the Company believes its annual rent will increase by approximately $10,000 as the rent under the BioMed lease will be greater than the rent applicable under the WDC lease as of April 2006.

The Company has agreed it will exercise its purchase option with respect to equipment acquired through several operating leases at the end of the lease terms. As a result, the Company will record capital lease obligations of approximately $15,000 relating to these leases as of the date of closing. The Company will transfer ownership of this facility-related equipment to BioMed at the earlier of the end of the Traville lease term or certain other pre-specified events.

With respect to the Large-Scale Manufacturing facility, the Company has agreed to sell this facility and land, but excluding the equipment, to BioMed for approximately $200,000. The Company expects to incur transaction costs of approximately $2,000 associated with this transaction.

For the LSM, the Company is entering into a twenty year lease, with a buy-out option exercisable during the first three years, with BioMed with initial annual rent of approximately $19,750. Aggregate rental payments over the twenty year period are approximately $480,000, including an expected annual escalation of 2%. The Company will be required to restrict investments of approximately $22,000 to serve as a security deposit under this lease.

The Company will transfer ownership of its LSM-related equipment to BioMed at the earlier of the end of the LSM lease term or certain other pre-specified events.

The Company is in the process of determining the accounting treatment for the BioMed agreement, including an evaluation of any non-cash charges with respect to the terminating of the WDC lease as well as the operating or capital lease treatment for the new Traville lease. The Company believes it will account for the LSM lease as a capital lease.

Note 9. Reclassifications

Certain prior period balances have been reclassified to conform to 2006 presentation.

MANAGEMENT’S DISCUSSION AND ANALYSIS OF
FINANCIAL CONDITION AND RESULTS OF OPERATIONS

Three Months Ended March 31, 2006 and 2005

Overview

Human Genome Sciences is a biopharmaceutical company with a pipeline of novel protein and antibody drugs directed toward large markets that have significant unmet medical needs. Our mission is to discover, develop, manufacture and market innovative drugs that serve patients with unmet medical needs, with a primary focus on protein and antibody products.

We are conducting clinical trials with a number of our products. Our current focus is to advance clinical trials in two main therapeutic areas: immunology/infectious disease and oncology. Additional products are in clinical development by companies with which we are collaborating or have out-licensed development rights.

We have developed and continue to enhance the resources necessary to achieve our goal of becoming a fully integrated global biopharmaceutical company. We have expanded our manufacturing facilities to allow us to produce larger quantities of therapeutic protein and antibody drugs for clinical development. We have completed construction and are in the validation phase of a large-scale manufacturing facility to increase our capacity for therapeutic protein and antibody drug production. We anticipate placing the facility into operational service in the second half of 2006. We are strengthening our commercial operations staff, and our intent is to add marketing and sales staff as needed as our products approach commercialization.

We have relationships with a number of leading pharmaceutical and biotechnology companies to leverage our strengths and to gain access to complementary technologies and sales and marketing infrastructure. Some of these partnerships provide us, and have provided us, with research funding, licensing fees, milestone payments and royalty payments as products are developed and commercialized. In some cases, we also are entitled to certain commercialization, co-development, revenue sharing and other product rights.

We have not received any significant product sales revenue or royalties from product sales and any significant revenue from product sales or from royalties on product sales in the next several years is uncertain. To date, all of our revenue relates to payments made under our collaboration agreements with GlaxoSmithKline (“GSK”) and, to a lesser extent, other agreements. In the third quarter of 2005, GSK exercised its option to co-develop and co-commercialize two of our products, LymphoStat-B™ and HGS-ETR1. Under the terms of a 1996 agreement, we and GSK will share equally in Phase 3 and 4 development costs, and will share equally in sales and marketing expenses and profits of any product that is commercialized, under a co-development and commercialization agreement, the remaining terms of which are being negotiated by the parties for LymphoStat-B. We may not receive any future payments and may not be able to enter into additional collaboration agreements.

We have entered into a two-phase contract to supply ABthrax™, a human monoclonal antibody developed for use in the treatment of anthrax disease, with the U.S. Government. Under the first phase of the contract, we have supplied ten grams of ABthrax to the U.S. Department of Health and Human Services (“HHS”) for comparative in vitro and in vivo testing. Under the second phase of the contract, the U.S. Government has the option to place an order by September 2006 for up to 100,000 doses of ABthrax for the Strategic National Stockpile, for use in the treatment of anthrax disease. The HHS comparative testing results, along with our own preclinical and clinical study results, will form the basis of the U.S. Government’s decision process for exercising its option for product for the Strategic National Stockpile. We do not know whether the U.S. Government will purchase ABthrax, and if it does, the timing, extent and amount of such purchases.

We expect that any significant revenue or income for at least the next several years may be limited to investment income, payments under various collaboration agreements to the extent milestones are met, payments from the sale of product rights and other payments from other collaborators and licensees under existing or future arrangements, to the extent that we enter into any future arrangements. We expect to continue to incur substantial expenses

Overview (continued)

relating to our research and development efforts, as we focus on clinical trials required for the development of antibody and protein product candidates. As a result, we expect to incur continued and significant losses over the next several years unless we are able to realize additional revenues under existing or new agreements. The timing and amounts of such revenues, if any, cannot be predicted with certainty and will likely fluctuate sharply. Results of operations for any period may be unrelated to the results of operations for any other period. In addition, historical results should not be viewed as indicative of future operating results.

We have recorded stock-based employee compensation of $6.7 million for the three months ended March 31, 2006, related to our employee stock incentive plan. Prior to January 1, 2006, we accounted for those plans under the recognition and measurement provisions of Accounting Principles Board Opinion No. 25, “Accounting for Stock Issued to Employees” (“APB No. 25”), and related Interpretations, as permitted by Financial Accounting Standards Board (“FASB”) Statement No. 123, “Accounting for Stock-Based Compensation” (“SFAS 123”). Effective January 1, 2006, we adopted the fair value recognition provisions of FASB Statement No. 123(R), “Share-Based Payment” (”SFAS 123(R)”), using the modified-prospective method. The fair value of each option grant is estimated on the date of grant using the Black-Scholes-Merton option-pricing model. Total compensation cost related to nonvested awards not yet recognized is expected to be approximately $60.3 million over 2.9 years.

Critical Accounting Policies and the Use of Estimates

A “critical accounting policy” is one that is both important to the portrayal of our financial condition and results of operations and that requires management’s most difficult, subjective or complex judgments. Such judgments are often the result of a need to make estimates about the effect of matters that are inherently uncertain. The preparation of our financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. Our accounting policies are described in more detail in Note B, Summary of Significant Accounting Policies, to our consolidated financial statements included in our 2005 Annual Report on Form 10-K.

The following is an update to those critical accounting policies impacted by standards that took effect in 2006:

Investments. We account for investments in accordance with Statement of Financial Accounting Standards (“SFAS”) No. 115, Accounting for Certain Investments in Debt and Equity Securities. We carry our investments at their respective fair values. We periodically evaluate the fair values of our investments to determine whether any declines in the fair value of investments represent an other-than-temporary impairment. This evaluation consists of a review of several factors, including but not limited to the length of time and extent that a security has been in an unrealized loss position, the existence of an event that would impair the issuer’s future repayment potential, the near term prospects for recovery of the market value of a security and our intent and ability to hold the security until the market values recover, which may be maturity. If management determines that such an impairment exists we would recognize an impairment charge. Because we may determine that market or business conditions may lead us to sell a short-term investment or marketable security prior to maturity, we classify our short-term investments and marketable securities as “available-for-sale.” Investments in securities that are classified as available-for-sale and have readily determinable fair values are measured at fair market value in the balance sheets, and unrealized holding gains and losses for these investments are reported as a separate component of stockholders’ equity until realized. If we held investments that were classified as “held-to-maturity” securities, these would be carried at amortized cost rather than at fair market value. If we held investments that were classified as “trading” securities, these would be carried at fair market value, with a corresponding adjustment to earnings for any change in fair market value. We classify those marketable securities that are likely to be used in operations within one year as short-term investments. Those marketable securities in which we have both the intent and ability to hold until maturity and have a maturity date beyond one year from our most recent consolidated balance sheet date are classified as non-current marketable securities.

Critical Accounting Policies and the Use of Estimates (continued)

In November 2005, the Financial Accounting Standards Board issued FASB Staff Position (“FSP”) FAS 115-1, The Meaning of Other-Than-Temporary Impairment and Its Application to Certain Investments (“FSP FAS 115-1”). FSP FAS 115-1 provides guidance on other-than-temporary impairment models for marketable debt and equity securities accounted for under SFAS No. 115 and non-marketable equity securities accounted for under the cost method. We adopted this guidance effective January 1, 2006. FSP FAS 115-1 provides a basic three-step model to evaluate whether an investment is other-than-temporarily impaired. Other than temporary losses on short-term investments and marketable securities would be expensed rather than included in stockholders’ equity. For those unrestricted investments not scheduled to mature within one year and not needed for current operations, we have classified these investments as non-current marketable securities. We believe we have the ability to hold our temporarily impaired securities until their market values recover, which may be maturity. The adoption of FSP FAS 115-1 did not have a material effect on our results of operations, financial condition or liquidity.

Stock Compensation. We have stock option plans under which options to purchase shares of our common stock may be granted to employees, consultants and directors at a price no less than the fair market value on the date of grant. Prior to 2006, we accounted for grants to employees in accordance with the provisions of APB No. 25, Accounting for Stock Issued to Employees (“APB No. 25”). Under APB No. 25, compensation expense is based on the difference, if any, on the date of the grant between the fair value of our stock and the exercise price of the option and is recognized ratably over the vesting period of the option. Because our options must be granted with an exercise price no less than the quoted market value of our common stock at the date of grant, we recognized no stock compensation expense at the time of the grant in accordance with APB No. 25. In December 2004, the Financial Accounting Standards Board (“FASB”) issued Statement of Financial Accounting Standards No. 123 (revised 2004), Share-Based Payment (“SFAS 123(R)”), which is a revision of Statement No. 123, Accounting for Stock-Based Compensation. In April 2005, the Securities and Exchange Commission adopted a rule that amended the adoption dates for SFAS 123(R), allowing us to implement SFAS 123(R) on January 1, 2006. The SEC rule does not otherwise change the accounting required by SFAS 123(R). SFAS 123(R) superseded APB Opinion No. 25, Accounting for Stock Issued to Employees. SFAS 123(R) requires all share-based payments to employees, including grants of employee stock options, to be recognized in the financial statements based on their fair values. In accordance with SFAS 123(R), we began recording compensation expense for all option awards beginning January 1, 2006 under the modified prospective method. The amount of compensation expense recognized using the fair value method requires us to exercise judgment and make assumptions relating to the factors that determine the fair value of our stock option grants. We use the Black-Scholes-Merton model to estimate the fair value of our option grants. The fair value calculated by this model is a function of several factors, including grant price, the risk-free interest rate, the estimated term of the option and the estimated future volatility of the option. In the event any of these inputs increases from 2005 levels, the fair value of new stock options on a per share basis will increase. The estimated term and estimated future volatility of the option require our judgment. The aggregate stock option expense to be recognized in 2006 and beyond is a function of the fair value associated with the vesting of existing grants as well as the new grants. This aggregate option expense may increase or decrease depending upon the quantity of options vesting and their relative fair value, net of option cancellations. The adoption of SFAS 123(R) did have an adverse effect on our results of operations, but did not affect our financial condition or liquidity.

Results of Operations

Revenues. Revenues were $6.8 million for the three months ended March 31, 2006 compared to revenues of $1.1 million for the three months ended March 31, 2005. Revenues for the three months ended March 31, 2006 consisted primarily of $6.0 million in revenue recognized from GSK for a milestone achievement related to GSK716155 (formerly known as Albugon^TM). Revenues for the three months ended March 31, 2005 consisted primarily of $0.6 million in revenue recognized from Transgene relating to a 1998 collaboration agreement.

Results of Operations (continued)

Expenses. Research and development expenses were $58.4 million for the three months ended March 31, 2006 compared to $54.2 million for the three months ended March 31, 2005. Research and development expenses included stock-based compensation expense of $4.3 million for the three months ended March 31, 2006. We track our research and development expenditures by type of cost incurred – research, pharmaceutical operations, manufacturing and clinical development costs.

Our research costs increased to $9.2 million for the three months ended March 31, 2006 from $7.5 million for the three months ended March 31, 2005. This increase is primarily due to general research costs across various drug candidates in addition to $0.7 million of stock-based compensation expense recognized for the three months ended March 31, 2006.

Our pharmaceutical operations costs, where we focus on improving formulation, process development and production methods, decreased to $9.4 million for the three months ended March 31, 2006 from $9.7 million for the three months ended March 31, 2005. This decrease is primarily due to reduced process development activities for LymphoStat-B^TM, HGS-ETR2 and HGS-ETR1, partially offset by increased activity for Albuferon^TM and ABthrax^TM and $0.7 million of stock-based compensation expense recognized for the three months ended March 31, 2006.

Our manufacturing costs increased to $20.4 million for the three months ended March 31, 2006 from $16.1 million for the three months ended March 31, 2005. This increase is primarily due to increased production activities for LymphoStat-B and Albuferon along with the work underway for the validation of our manufacturing facility and $1.2 million in stock-based compensation expense recognized for the three months ended March 31, 2006, partially offset by decreased costs related to HGS-ETR2 and Albugon.

Our clinical development costs decreased to $19.3 million for the three months ended March 31, 2006 from $20.9 million for the three months ended March 31, 2005. This decrease is primarily due to the cost of decreased trial activity for Albuferon, partially offset by an increase for stock-based compensation expense of $1.7 million recognized for the three months ended March 31, 2006.

General and administrative expenses increased to $13.4 million for the three months ended March 31, 2006 compared to $9.4 million for the three months ended March 31, 2005. This increase is primarily due to stock-based compensation expense of $2.4 million recognized for the three months ended March 31, 2006 and increased legal costs.

Investment income decreased to $5.1 million for the three months ended March 31, 2006 from $6.2 million for the three months ended March 31, 2005. The decrease in investment income for the three months ended March 31, 2006 is due to lower average cash and short-term investment balances, partially offset by an increased yield due to rising average interest rates of the securities in our portfolio. Investment income also includes net realized gains and losses on our short-term, marketable securities, restricted and long-term investments. For our investments, we recorded a net loss of $0.2 million for the three months ended March 31, 2006 and a net loss of $1.0 million for the three months ended March 31, 2005. Our average cash balance decreased during 2006 as a result of our net losses and capital expenditures in 2006.

Interest expense decreased to $2.3 million for the three months ended March 31, 2006 compared to $3.3 million for the three months ended March 31, 2005, primarily due to the replacement of existing debt with more favorable interest-bearing notes in 2005 and 2004. Interest expense is net of interest capitalized in connection with the construction of our large-scale manufacturing facility.

Facility Financing. In May 2006, we entered into a Purchase and Sale agreement with BioMed Realty, LLP (“BioMed”) to either sell or cause to be sold the Traville facility, the Traville land and the Large-Scale Manufacturing facility (“LSM”) and concurrently entered into long-term lease agreements with BioMed for the two facilities. We expect to record a loss of approximately $4.7 million associated with this transaction.

Results of Operations (continued)

For Traville, we are entering into a twenty year lease, with a buy-out option after ten years, with BioMed with initial annual rent of approximately $19.8 million. As a result of entering into this lease, we believe our annual rent will increase by approximately $10.0 million as the rent under the BioMed lease will be greater than the rent applicable under the WDC lease as of April 2006.

With respect to the Large-Scale Manufacturing facility, we have agreed to sell this facility and land, but excluding the equipment, to BioMed for approximately $200.0 million. We expect to record a loss of approximately $4.7 million associated with this transaction. Assuming this transaction is completed by the end of the second quarter of 2006, we anticipate our interest income to increase by approximately $4.0 million for the remainder of 2006 due to the increase in our cash and investments that will arise from this transaction.

For LSM, we are entering into a twenty year lease, with a buy-out option exercisable during the first three years, with BioMed with initial annual rent of approximately $19.8 million.

Assuming the cost of the manufacturing facility reaches approximately $233.0 million when construction is complete and production activities commence later in 2006, cumulative capitalized interest at that time could approximate $12.9 million. Total interest expense, before capitalized interest, was $3.6 million and $4.7 million for the three months ended March 31, 2006 and 2005, respectively.

We are in the process of determining the accounting treatment for the BioMed agreement, including an evaluation of any non-cash charges with respect to the terminating of the WDC lease as well as the operating or capital lease treatment for the new Traville lease. We believe we will account for the LSM lease as a capital lease, which will result in depreciation that we believe will approximate the depreciation expense had we continued to own the LSM. See Note 8 of the Notes to Consolidated Financial Statements for additional discussion.

Net Income (Loss). We recorded a net loss of $62.1 million, or $0.47 per share, for the three months ended March 31, 2006 compared to a net loss of $59.6 million, or $0.46 per share, for the three months ended March 31, 2005. The increased loss for the three months ended March 31, 2006 is due to the recognition of $6.7 million of stock-based compensation expense related to the adoption of SFAS 123(R) on January 1, 2006, partially offset by increased revenues.

Our net loss of $62.1 million, or $0.47 per share, includes a charge for stock-based compensation of $6.7 million, or $0.05 per share, for the three months ended March 31, 2006. Our net loss of $59.6 million, or $0.46 per share, for the three months ended March 31, 2005, includes no stock-based compensation expense as we did not adopt SFAS 123(R) until January 1, 2006.

As a result of adopting Statement 123(R) on January 1, 2006, our net income for the three months ended March 31, 2006, is approximately $6.7 million, or $0.05 per share, lower than if we had continued to account for stock-based compensation under APB No. 25. For the three months ended March 31, 2005, if we had accounted for employee stock options under the recognition provisions of SFAS 123, we would have recognized approximately $8.8 million, or $0.06 per share, of additional expense.

Liquidity and Capital Resources

We had working capital of $202.6 million and $128.9 million at March 31, 2006 and December 31, 2005, respectively. The increase in our working capital for the three months ended March 31, 2006 is primarily due to the realignment of our investment portfolio, an increase in securities due within one year, partially offset by our net loss and our capital expenditures during this period. As discussed in the Results of Operations, we entered into a facility financing agreement in May 2006 that we anticipate concluding by mid-2006. Upon closing, the Traville component of this financing will reduce our restricted investments and increase our unrestricted investment balances by approximately $180.0 million and add another approximately $25.0 million in unrestricted cash and the LSM component of this financing will increase our unrestricted cash balances by approximately $175.0 million. As a result, on an aggregate basis, we anticipate our working capital to increase by approximately $380.0 million as a result of this transaction.

Liquidity and Capital Resources (continued)

We expect to continue to incur substantial expenses relating to our research and development efforts, which may increase relative to historical levels as we focus on manufacturing and clinical trials required for the development of our active product candidates. We may continue to improve our working capital position during 2006 through the receipt of collaboration fees or financing activities. In the event our working capital needs for 2006 exceed our available working capital, after these or other initiatives, we can utilize our non-current marketable securities, which are classified as “available-for-sale”. We evaluate our working capital position on a continual basis.

The amounts of expenditures that will be needed to carry out our business plan are subject to numerous uncertainties, which may adversely affect our liquidity and capital resources. We have several Phase 1 and Phase 2 trials underway and expect to initiate additional trials, including Phase 3 trials, in the future. Completion of these trials may extend several years or more, but the length of time generally varies considerably according to the type, complexity, novelty and intended use of the drug candidate. We estimate that the completion periods for our Phase 1, Phase 2 and Phase 3 trials could span one year, one to two years and two to four years, respectively. Some trials may take considerably longer to complete.

The duration and cost of our clinical trials are a function of numerous factors such as the number of patients to be enrolled in the trial, the amount of time it takes to enroll them, the length of time they must be treated and observed, and the number of clinical sites and countries for the trial.

Our clinical development expenses are impacted by the clinical phase of our drug candidates. Our expenses increase as our drug candidates move to later phases of clinical development. The status of our clinical projects is as follows:


		CLINICAL TRIAL
		STATUS AS
		OF MARCH 31, (2)
PRODUCT
CANDIDATE (1)	INDICATION	2006			2005
ACTIVE CANDIDATES:

Antibodies:
LymphoStat-B	Rheumatoid Arthritis	Phase 2 (3)			Phase 2
LymphoStat-B	Systemic Lupus Erythematosus	Phase 2 (4)			Phase 2
HGS-ETR1	Cancer	Phase 2			Phase 2
HGS-ETR2	Cancer	Phase 1			Phase 1
HGS-TR2J	Cancer	Phase 1			Phase 1
CCR5 mAb	HIV	Phase 1			Phase 1
ABthrax	Anthrax		(5	)		(5	)

Albumin Fusion Proteins:
Albuferon	Hepatitis C	Phase 2 (6)			Phase 2

INACTIVE CANDIDATES:

Other:
LymphoRad¹³¹	Cancer		(7	)	Phase 1


(1)		Includes only those candidates for which an Investigational New Drug (“IND”) application has been filed with the FDA.

(2)		Clinical Trial Status defined as when patients are being dosed.

(3)		Initial Phase 2 trial completed; extension safety study ongoing.

(4)		Initial Phase 2 trial completed; extension safety study ongoing; Phase 3 planning underway.

Liquidity and Capital Resources (continued)


(5)		U.S. Government has executed the first phase of the contract in which we supplied ten grams of ABthrax to HHS for comparative in vitro and in vivo testing. Under the second phase of the contract, the U. S. Government has the option to place an order by September 2006 for up to 100,000 doses of ABthrax. Further clinical development pending and dependent on the U.S. Government.

(6)		Phase 2 trials continuing; Phase 3 planning underway.

(7)		Clinical development discontinued in 2005.

Our clinical trial status as of December 31, 2005, 2004 and 2003 is contained in our 2005 Annual Report on Form 10-K.

We identify our potential drug candidates by conducting numerous preclinical studies. We may conduct multiple clinical trials to cover a variety of indications for each drug candidate. Based upon the results from our trials, we may elect to discontinue clinical trials for certain indications or certain drugs in order to concentrate our resources on more promising drug candidates.

We are advancing a number of drug candidates, antibodies and albumin fusion proteins, in part to diversify the risks associated with our research and development spending. In addition, our manufacturing plants have been designed to enable multi-product manufacturing capability. Accordingly, we believe our future financial commitments, including those for preclinical, clinical or manufacturing activities, are not substantially dependent on any single drug candidate. Should we be unable to sustain a multi-product drug pipeline, our dependence on the success of a single drug candidate would increase.

We must receive regulatory clearance to advance each of our products into and through each phase of clinical testing. Moreover, we must receive regulatory approval to launch any of our products commercially. In order to receive such approval, the appropriate regulatory agency must conclude that our clinical data establish safety and efficacy and that our products and the manufacturing facilities meet all FDA requirements. We cannot be certain that we will establish sufficient safety and efficacy data to receive regulatory approval for any of our drugs or that our drugs and the manufacturing facilities will meet all applicable regulatory requirements.

In addition, part of our business plan includes collaborating with others. For example, GSK is developing products as part of our collaboration or licensing with them. We have no control over the progress of GSK’s development plans. While we have recognized $6.0 million from GSK in connection with a development milestone met by GSK during 2006 relating to our 2004 agreement with GSK, we cannot forecast with any degree of certainty the likelihood of receiving future milestone or royalty payments under these agreements. We cannot forecast with any degree of certainty what impact GSK’s decision to jointly develop and commercialize LymphoStat-B and HGS-ETR1 will have on our development costs, in part because joint development agreements must first be concluded. We also cannot forecast with any degree of certainty whether any of our current or future collaborations will affect our drug development efforts and therefore, our capital and liquidity requirements.

Because of the uncertainties discussed above, the costs to advance our research and development projects are difficult to estimate and may vary significantly. We expect that our existing funds and investment income will be sufficient to fund our operations for at least the next twelve months.

Our future capital requirements and the adequacy of our available funds will depend on many factors, primarily including the scope and costs of our clinical development programs, the scope and costs of our manufacturing and process development activities and the magnitude of our discovery program. There can be no assurance that any additional financing required in the future will be available on acceptable terms, if at all.

Liquidity and Capital Resources (continued)

Depending upon market and interest rate conditions, we are exploring, and, from time to time, may take actions to strengthen further our financial position. In this regard, during 2005, we refinanced approximately $230.0 million of our convertible subordinated debt. We may undertake other financings and may further repurchase or restructure some or all of our outstanding convertible debt instruments in the future depending upon market and other conditions.

We have certain contractual obligations, including one which is not recorded on our balance sheets, which may have a future effect on our financial condition, changes in financial condition, results of operations, liquidity, capital expenditures or capital resources that is material to investors. See “Off-Balance Sheet Arrangements” below for additional discussion. Our operating leases, along with our unconditional purchase obligations, are not recorded on our balance sheets.

Our unrestricted and restricted funds may be invested in U.S. Treasury securities, government agency obligations, high grade corporate debt securities and various money market instruments rated “A” or better. Such investments reflect our policy regarding the investment of liquid assets, which is to seek a reasonable rate of return consistent with an emphasis on safety, liquidity and preservation of capital.

Off-Balance Sheet Arrangements

As of March 31, 2006, we have one lease agreement for a research and development and administrative facility (the “Traville lease”) which has been structured as a synthetic lease and is accounted for as an operating lease. This structure provides us with cost-effective financing and future financing flexibility. None of our directors, officers or employees has any financial interest with regard to this lease arrangement.

The Traville lease has a term of approximately seven years beginning in 2003 and relates to a research and development and administrative facility located on the Traville site in Rockville, Maryland. The total financed cost of the Traville lease facility is $200.0 million. Our rent obligation approximates the lessor’s debt service costs plus a return on the lessor’s equity investment. The rent under this lease is currently based on the rate for short-term commercial paper, but the lessor can lock in a fixed interest rate at any time at our request. To the extent the lessor does not lock in a fixed interest rate, if interest rates increase, our rent obligations would also increase. If interest rates decrease, our rent obligations would decrease. The current floating rate was approximately 4.6% as of March 31, 2006.

Our restricted investments with respect to the Traville lease and other leases for the existing process development and manufacturing facility are expected to reach approximately $219.0 million. These restricted investments will serve as collateral for the duration of the leases. We are required to restrict investments for the duration of the lease equal to 102% of the full amount of the $200.0 million financed project cost for the Traville lease, or $204.0 million. Also, in connection with the Traville lease, we must maintain minimum levels of unrestricted cash, cash equivalents and marketable securities and certain debt ratios. In addition, we are required to maintain up to a maximum of $15.0 million in restricted investments with respect to the process development and manufacturing facility leases. Our restricted investments for all of these leases aggregated approximately $217.2 million as of March 31, 2006 compared to approximately $220.2 million as of December 31, 2005.

Under the Traville lease, we have the option to purchase the property during and at the end of the lease term for $200.0 million. Alternatively, we can cause the property to be sold to third parties. We are contingently liable for the residual value guarantee associated with this property in the event the net sale proceeds are less than the original financed cost of the facility. We are contingently liable for the residual value guarantee associated with the Traville lease of $175.5 million. See Note 4, Commitments and Other Matters and Note 8, Subsequent Event for additional discussion.

Our off-balance sheet arrangement will be dissolved upon the conclusion of the BioMed transaction. At that time, we will no longer have an off-balance sheet arrangement with respect to the Traville facility. We have not yet determined the accounting treatment for the new Traville lease. In addition, as part of the BioMed agreement, we have agreed to acquire the equipment currently under lease. As a result, we will account for the remainder of the operating lease liability, estimated to be approximately $15.0 million, as a capital lease. We will be accounting for the LSM lease as a capital lease.

Safe Harbor Statement Under the Private Securities Litigation Reform Act of 1995

Certain statements contained in “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The forward-looking statements are based on our current intent, belief and expectations. These statements are not guarantees of future performance and are subject to certain risks and uncertainties that are difficult to predict. Actual results may differ materially from these forward-looking statements because of our unproven business model, our dependence on new technologies, the uncertainty and timing of clinical trials, our ability to develop and commercialize products, our dependence on collaborators for services and revenue, our substantial indebtedness and lease obligations, our changing requirements and costs associated with planned facilities, intense competition, the uncertainty of patent and intellectual property protection, our dependence on key management and key suppliers, the uncertainty of regulation of products, the impact of future alliances or transactions and other risks described in this filing and our other filings with the Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today’s date. We undertake no obligation to update or revise the information contained in this announcement whether as a result of new information, future events or circumstances or otherwise.

Item 3. Quantitative and Qualitative Disclosures About Market Risk

We do not have operations of a material nature that are subject to risks of foreign currency fluctuations, nor do we use derivative financial instruments in our operations or investment portfolio. Our investment portfolio may only be comprised of low-risk U.S. Treasuries, government agency obligations, high-grade debt having at least an “A” rating and various money market instruments. The short-term nature of these securities, which currently have an average term of approximately 16 months, significantly decreases the risk of a material loss caused by a market change. We believe that a hypothetical 100 basis point adverse move (increase) in interest rates along the entire interest rate yield curve would adversely affect the fair value of our cash, cash equivalents, short-term investments, marketable securities and restricted investments by approximately $8.0 million, or approximately 1.4% of the aggregate fair value of $580.4 million, at March 31, 2006. For these reasons, and because these securities are generally held to maturity, we believe we do not have significant exposure to market risks associated with changes in interest rates related to our debt securities held as of March 31, 2006. We believe that any market change related to our investment securities held as of March 31, 2006 is not material to our consolidated financial statements. As of March 31, 2006, the yield on comparable two-year investments was approximately 4.8%, as compared to our current portfolio yield of approximately 3.4%. However, given the short-term nature of these securities, a general decline in interest rates may adversely affect the interest earned from our portfolio as securities mature and may be replaced with securities having a lower interest rate.

As of March 31, 2006, the market values of our equity investments in CAT and Corautus were approximately $13.4 million and $5.5 million, respectively. Our investment in Corautus is subject to equity market risk. Our investment in CAT is denominated in pounds sterling and is subject to both foreign currency risk as well as equity market risk.

The facility lease we entered into during 2003 requires us to maintain minimum levels of restricted investments as collateral for this facility. Our restricted investments for this lease had reached the maximum level of approximately $204.0 million as of March 31, 2006. Together with the requirement to maintain up to approximately $15.0 million in restricted investments with respect to our process development and manufacturing facility leases, our overall level of restricted investments will reach $219.0 million. Although the market value for these investments may rise or fall as a result of changes in interest rates, we will be required to maintain this level of restricted investments in either a rising or declining interest rate environment. Our restricted investment will decline significantly as a result of the anticipated BioMed transaction.

Item 3. Quantitative and Qualitative Disclosures About Market Risk (continued)

The rent under the Traville lease is based on a floating interest rate. We can direct the lessor to lock in a fixed interest rate. As of March 31, 2006, such a fixed rate for five years would be approximately 5.3% compared to the floating rate as of March 31, 2006 of approximately 4.6%. If interest rates increase, our rent obligations would also increase, which would result in an increase in our operating expenses. Our rent under this lease will no longer be based on a floating interest rate as a result of the anticipated BioMed transaction.

Changes in interest rates do not affect interest expense incurred on our Convertible Subordinated Notes because they bear interest at fixed rates.

During 2002, we established a wholly-owned subsidiary, Human Genome Sciences Europe GmbH (“HGS Europe”), which manages our clinical trials and clinical research collaborations in European countries. Although HGS Europe’s activities are denominated primarily in euros, we believe the foreign currency fluctuation risks for 2006 to be immaterial to our operations as a whole. In February 2005, we established a wholly-owned subsidiary, Human Genome Sciences Pacific Pty Ltd. (“HGS Pacific”) that will sponsor our clinical trials in the Asia\Pacific region. We currently do not anticipate HGS Pacific to have any operational activity and therefore we do not believe we will have any foreign currency fluctuation risks for 2006 with respect to HGS Pacific.

Item 4. Controls and Procedures

Disclosure Controls and Procedures

Our management, including our principal executive and principal financial officers, has evaluated the effectiveness of our disclosure controls and procedures as of March 31, 2006. Our disclosure controls and procedures are designed to provide reasonable assurance that the information required to be disclosed in this Quarterly Report on Form 10-Q has been appropriately recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms, and that such information is accumulated and communicated to our management, including our principal executive and principal financial officers, to allow timely decisions regarding required disclosure. Based on that evaluation, our principal executive and principal financial officers have concluded that our disclosure controls and procedures are effective at the reasonable assurance level.

Changes in Internal Control

Our management, including our principal executive and principal financial officers, has evaluated any changes in our internal control over financial reporting that occurred during the quarterly period ended March 31, 2006, and has concluded that there was no change that occurred during the quarterly period ended March 31, 2006 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

PART II. OTHER INFORMATION

Item 1a. Factors That May Affect Our Business

There are a number of risk factors that could cause our actual results to differ materially from those that are indicated by forward-looking statements. Those factors include, without limitation, those listed below and elsewhere herein.

If we are unable to commercialize products, we may not be able to recover our investment in our product development and manufacturing efforts.

We have invested significant time and resources to isolate and study genes and determine their functions. We now devote most of our resources to developing proteins and antibodies for the treatment of human disease. We are also devoting substantial resources to the establishment of our own manufacturing capabilities, both to support clinical testing and eventual commercialization. We have made and are continuing to make substantial expenditures. Before we can commercialize a product, we must rigorously test the product in the laboratory and complete extensive human studies. We cannot assure you that the costs of testing and study will yield products approved for marketing by the FDA or that any such products will be profitable. We will incur substantial additional costs to continue these activities. If we are not successful in commercializing products, we may be unable to recover the large investment we have made in research, development and manufacturing facilities.

Because our product development efforts depend on new and rapidly-evolving technologies, we cannot be certain that our efforts will be successful.

Our work depends on new, rapidly evolving technologies and on the marketability and profitability of innovative products. Commercialization involves risks of failure inherent in the development of products based on innovative technologies and the risks associated with drug development generally. These risks include the possibility that:

	•		these technologies or any or all of the products based on these technologies will be ineffective or toxic, or otherwise fail to receive necessary regulatory clearances;

	•		the products, if safe and effective, will be difficult to manufacture on a large-scale or uneconomical to market;

	•		proprietary rights of third parties will prevent us or our collaborators from exploiting technologies or marketing products; and

	•		third parties will market superior or equivalent products.

Because we are currently a mid-stage development company, we cannot be certain that we can develop our business or achieve profitability.

We expect to continue to incur losses and we cannot assure you that we will ever become profitable. We are in the mid-stage of development, and it will be a number of years, if ever, before we are likely to receive revenue from product sales or royalty payments. We will continue to incur substantial expenses relating to research and development efforts and human studies. The development of our products requires significant further research, development, testing and regulatory approvals. We may not be able to develop products that will be commercially successful or that will generate revenue in excess of the cost of development.

We are continually evaluating our business strategy, and may modify this strategy in light of developments in our business and other factors.

In the past, we have redirected the focus of our business from the discovery of genes to the development of medically useful products based on those genes. We continue to evaluate our business strategy and, as a result, may modify this strategy in the future. In this regard, we may, from time to time, focus our product development efforts on different products or may delay or halt the development of various products. In addition, as a result of changes in our strategy, we may also change or refocus our existing drug discovery, development, commercialization and manufacturing activities. This could require changes in our facilities and personnel and the restructuring of various financial arrangements. We cannot assure you that changes will occur or that any changes that we implement will be successful.

During the past two years, we have sharpened our focus on our most promising drug candidates. We have reduced the number of drugs in early development and are focusing our resources on the drugs that address the greatest unmet medical needs with substantial growth potential. In order to significantly reduce our expenses, and thus enable us to dedicate more resources to the most promising drugs, we have reduced staff, streamlined operations and consolidated facilities. In December 2005, we entered into an agreement to spin off our CoGenesys division as an independent company, in a transaction that will be treated as a sale for accounting purposes. CoGenesys will focus on the development of assets that were unlikely to be developed by us.

Our ability to discover and develop new early stage preclinical products will depend on our internal research capability. We substantially reduced our internal research capability as part of our restructuring in the first quarter of 2004. Our internal research capability will be further reduced if we complete the previously announced spin-off of CoGenesys. Although we continue to conduct discovery and development efforts on early stage products, our limited resources for discovering and developing early stage preclinical products may not be sufficient to discover new preclinical drug candidates.

PRODUCT DEVELOPMENT RISKS

Because we have limited experience in developing and commercializing products, we may be unsuccessful in our efforts to do so.

Our ability to develop and commercialize products based on proteins, antibodies and other compounds will depend on our ability to:

	•		develop products internally;

	•		complete laboratory testing and human studies;

	•		obtain and maintain necessary intellectual property rights to our products;

	•		obtain and maintain necessary regulatory approvals related to the efficacy and safety of our products;

	•		develop and expand production facilities meeting all regulatory requirements or enter into arrangements with third parties to manufacture our products on our behalf; and

	•		deploy sales and marketing resources effectively or enter into arrangements with third parties to provide these functions.

Although we are conducting human studies with respect to a number of products, we have limited experience with these activities and may not be successful in developing or commercializing these or other products.

Because clinical trials for our products are expensive and protracted and their outcome is uncertain, we must invest substantial amounts of time and money that may not yield viable products.

Conducting clinical trials is a lengthy, time-consuming and expensive process. Before obtaining regulatory approvals for the commercial sale of any product, we must demonstrate through laboratory, animal and human studies that such product is both effective and safe for use in humans. We will incur substantial additional expense for and devote a significant amount of time to these studies.

Before a drug may be marketed in the U.S., it must be the subject of rigorous preclinical testing. The results of these studies must be submitted to the FDA as part of an investigational new drug application, which is reviewed by the FDA before clinical testing in humans can begin. The results of preliminary studies do not predict clinical success. A number of potential drugs have shown promising results in early testing but subsequently failed to obtain necessary regulatory approvals. Data obtained from tests are susceptible to varying interpretations, which may delay, limit or prevent regulatory approval. Regulatory authorities may refuse or delay approval as a result of many other factors, including changes in regulatory policy during the period of product development.

Completion of clinical trials may take many years. The length of time required varies substantially according to the type, complexity, novelty and intended use of the product candidate. The FDA monitors the progress of each phase of testing, and may require the modification, suspension, or termination of a trial if it is determined to present excessive risks to patients. Our rate of commencement and completion of clinical trials may be delayed by many factors, including:

	•		our inability to manufacture sufficient quantities of materials for use in clinical trials;

	•		variability in the number and types of patients available for each study;

	•		difficulty in maintaining contact with patients after treatment, resulting in incomplete data;

	•		unforeseen safety issues or side effects;

	•		poor or unanticipated effectiveness of products during the clinical trials; or

	•		government or regulatory delays.

To date, data obtained from our clinical trials are not sufficient to support an application for regulatory approval without further studies. Studies conducted by us or by third parties on our behalf may not demonstrate sufficient effectiveness and safety to obtain the requisite regulatory approvals for these or any other potential products. Based on the results of a human study for a particular product candidate, regulatory authorities may not permit us to undertake any additional clinical trials for that product candidate. The clinical trial process may also be accompanied by substantial delay and expense and there can be no assurance that the data generated in these studies will ultimately be sufficient for marketing approval by the FDA. For example, in 2005, we discontinued our clinical development of LymphoRad¹³¹, a product candidate to treat cancer.

We face risks in connection with our ABthrax product in addition to risks generally associated with drug development.

Our entry into the biodefense field with the development of ABthrax presents risks beyond those associated with the development of our other products. Numerous other companies and governmental agencies, including the U.S. Army, are known to be developing biodefense pharmaceuticals and related products to combat anthrax. These competitors may have financial or other resources greater than ours, and may have easier or preferred access to the likely distribution channels for biodefense products. In addition, since the primary purchaser of biodefense products is the U.S. Government and its agencies, the success of ABthrax will depend on government spending policies and pricing restrictions. The funding of government biodefense programs is dependent, in part, on budgetary constraints, political considerations and military developments. In the case of the U.S. Government, executive or legislative action could attempt to impose production and pricing requirements on us. We have entered into a two-phase contract to supply ABthrax, a human monoclonal antibody developed for use in the treatment of anthrax disease, to the U.S. Government. Under the first phase of the contract, we will supply ten grams of ABthrax to the U.S. Department of Health and Human Services (“HHS”) for comparative in vitro and in vivo testing. Under the second phase of the contract, the U.S. Government has the option to place an order within one year for up to 100,000 doses of ABthrax for the Strategic National Stockpile, for use in the treatment of anthrax disease. We believe that the HHS comparative testing results, along with Human Genome Sciences’ own preclinical and clinical study results, will form the basis of the U.S. Government’s decision process for exercising its option for additional product for the Strategic National Stockpile. We do not know whether the U.S. Government will purchase ABthrax, and if it does, the timing, extent and amount of such purchases. If the U.S. Government decides to place an order for ABthrax, we will continue to face risks related to animal and human testing, to the manufacture of ABthrax and to FDA concurrence that ABthrax meets the requirements of the contract. If we are unable to meet the product requirements associated with this contract the U.S. Government will not be required to reimburse us for the costs incurred or to purchase any product pursuant to that order.

Because neither we nor any of our collaboration partners have received marketing approval for any product candidate resulting from our research and development efforts, and because we may never be able to obtain any such approval, it is possible that we may not be able to generate any product revenue.

Neither we nor any of our collaboration partners have completed development of any product based on our genomics research. It is possible that we will not receive FDA marketing approval for any of our product candidates. Although a number of our potential products have entered clinical trials, we cannot assure you that any of these products will receive marketing approval. All the products being developed by our collaboration partners will also require additional research and development, extensive preclinical studies and clinical trials and regulatory approval prior to any commercial sales. In some cases, the length of time that it takes for our collaboration partners to achieve various regulatory approval milestones may affect the payments that we are eligible to receive under our collaboration agreements. We and our collaboration partners may need to successfully address a number of technical challenges in order to complete development of our products. Moreover, these products may not be effective in treating any disease or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining regulatory approval or prevent or limit commercial use.

RISK FROM COLLABORATION RELATIONSHIPS AND STRATEGIC ACQUISITIONS

Our plan to use collaborations to leverage our capabilities and to grow in part through the strategic acquisition of other companies and technologies may not be successful if we are unable to integrate our partners’ capabilities or the acquired companies with our operations or if our partners’ capabilities do not meet our expectations.

As part of our strategy, we intend to continue to evaluate strategic partnership opportunities and consider acquiring complementary technologies and businesses. In order for our future collaboration efforts to be successful, we must first identify partners whose capabilities complement and integrate well with ours. Technologies to which we gain access may prove ineffective or unsafe. Our current agreements that grant access to such technology may expire and may not be renewable. Our partners may prove difficult to work with or less skilled than we originally expected. In addition, any past collaborative successes are no indication of potential future success. In order to achieve the anticipated benefits of an acquisition, we must integrate the acquired company’s business, technology and employees in an efficient and effective manner. The successful combination of companies in a rapidly changing biotechnology and genomics industry may be more difficult to accomplish than in other industries. The combination of two companies requires, among other things, integration of the companies’ respective technologies and research and development efforts. We cannot assure you that this integration will be accomplished smoothly or successfully. The difficulties of integration are increased by the necessity of coordinating geographically separated organizations and addressing possible differences in corporate cultures and management philosophies. The integration of certain operations will require the dedication of management resources which may temporarily distract attention from the day-to-day operations of the combined companies. The business of the combined companies may also be disrupted by employee retention uncertainty and lack of focus during integration. The inability of management to integrate successfully the operations of the two companies, in particular, to integrate and retain key scientific personnel, or the inability to integrate successfully two technology platforms, could have a material adverse effect on our business, results of operations and financial condition.

Although GSK has agreed to be our partner in the development and commercialization of LymphoStat-B and HGS-ETR1, we may be unable to negotiate an appropriate co-development and co-marketing agreement.

As part of our June 1996 agreement with GSK, we granted a 50/50 co-development and commercialization option to GSK for certain human therapeutic products that successfully complete Phase 2a clinical trials. On July 7, 2005, we announced that GSK had exercised its option to develop and commercialize LymphoStat-B (belimumab) jointly with us and on August 18, 2005, we announced that GSK had exercised its option to develop and commercialize HGS-ETR1 (mapatumumab) jointly with us. Under the terms of the 1996 agreement, GSK and we will share equally in Phase 3\4 development costs of these products, and will share equally in sales and marketing expenses and profits of any such product that is commercialized pursuant to co-development and commercialization agreements, the remaining terms of which are subject to negotiation. We do not know if we will be successful in negotiating such agreements, and if we are unsuccessful, we do not know if, and how, GSK and we will collaborate on these products.

If we complete the spin-off of our CoGenesys division, our ability to receive revenues from the assets transferred with CoGenesys will depend on CoGenesys’ ability to develop and commercialize those assets.

The spin-off of our CoGenesys division is contingent on the receipt by CoGenesys of third party financing. As a result, we cannot assure you that the transaction, which will be treated as a sale for accounting purposes, will be completed as currently structured. If the transaction is completed, we will depend on CoGenesys to develop and commercialize those assets. If CoGenesys is not successful in its efforts, we may not receive any revenue from the development of CoGenesys assets. CoGenesys will require significant third party financing, which may be unavailable. In addition, our relationship with CoGenesys will be subject to the risks and uncertainties inherent in our other collaborations.

Because we depend on our collaboration partners for revenue, we may not become profitable if we cannot increase the revenue from our collaboration partners or other sources.

We have received all of our revenue from payments made under our collaboration agreements with GSK and, to a lesser extent, other agreements. The initial research term of the GSK collaboration agreement and many of our other collaboration agreements expired in 2001. None of these collaboration agreements was renewed. We may not be able to enter into additional collaboration agreements. We are entitled to certain milestone and royalty payments from the existing collaborators, but may not receive payments if our collaborators fail to:

	•		develop marketable products;

	•		obtain regulatory approvals for products; or

	•		successfully market products based on our research.

Further, circumstances could arise under which one or more of our collaboration partners may allege that we breached our agreement with them and, accordingly, seek to terminate our relationship with them. If successful, this could adversely affect our ability to commercialize our products and harm our business.

If one of our collaborators pursues a product that competes with our products, there could be a conflict of interest and we may not receive the milestone or royalty payments that we expect.

Each of our collaborators is developing a variety of products, some with other partners. Our collaborators may pursue existing or alternative technologies to develop drugs targeted at the same diseases instead of using our licensed technology to develop products in collaboration with us. Our collaborators may also develop products that are similar to or compete with products they are developing in collaboration with us. If our collaborators pursue these other products instead of our products, we may not receive milestone or royalty payments.

FINANCIAL AND MARKET RISKS

Because of our substantial indebtedness, we may be unable to adjust our strategy to meet changing conditions in the future.

As of March 31, 2006, we had long-term obligations of approximately $510.0 million. We also had a future guarantee obligation of $200.0 million under the current terms of one facility lease. Our substantial debt and future guarantee will have several important consequences for our future operations. For instance:

	•		payments of interest on, and principal of, our indebtedness will be substantial, and may exceed then current revenues and available cash;

	•		a default under the terms of these existing obligations could result in the termination of certain leases and the acceleration of the maturity of our other financial obligations;

	•		we may be unable to obtain additional future financing for continued clinical trials, capital expenditures, acquisitions or general corporate purposes;

	•		we may be unable to withstand changing competitive pressures, economic conditions and governmental regulations; and

	•		we may be unable to make acquisitions or otherwise take advantage of significant business opportunities that may arise.

We have entered into an off-balance sheet facility lease arrangement that constitutes a significant financial obligation and possible risks to our financial condition.

In the second quarter of 2003, we entered into a facility lease for our research and development and administrative facility. Under U.S. generally accepted accounting principles, this lease was treated as an operating lease. In the event we default on our obligation under the lease, we may be responsible for up to $200.0 million of the cost of the facility because of a guarantee we made in connection with the lease. This obligation is not required to be reflected as a liability on our balance sheet, but is described in footnotes to our financial statements. We are required to pledge marketable securities as security for our obligation under the lease and the related documents. As of March 31, 2006, we included approximately $217.2 million of restricted investments on our balance sheet, of which approximately $204.5 million was held as restricted investments providing collateral for our obligation with respect to this facility. If the value of our pledged investments declines, because of an increase in interest rates or otherwise, we would need to pledge additional investments, which would further reduce our working capital. The rent under this lease is based on a floating interest rate, but the lessors at our request can lock in a fixed interest rate at an interest rate premium. To the extent the lessors do not lock in a fixed interest rate, if interest rates increase, our rent obligation would also increase. The lease has a term of seven years. If we desire to remain in the facility upon lease expiration, we would need to refinance or buy the facility at the financed project cost. We cannot assure you that refinancing will be available on comparable terms, if at all. Further, in the event the facility is sold, we have a guarantee obligation which makes us responsible to the extent that the value of the facility is less than the financed project cost and which will reach a maximum guarantee obligation of approximately $175.5 million if the value of the facility declined below approximately 12.25% of the financed project cost. While we believe that this lease provides a useful financing mechanism for the facility, adverse public perception of such lease arrangements and the associated risks may cause our stock price to decline. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Off-Balance Sheet Arrangements”.

To pursue our current business strategy and continue developing our products, we are likely to need substantial additional funding in the future. If we do not obtain this funding on acceptable terms, we may not be able to continue to grow our business and generate enough revenue to recover our investment in our product development effort.

Since inception, we have expended, and will continue to expend, substantial funds to continue our research and development programs. We are likely to need additional financing to fund our operating expenses and capital requirements. In the third quarter of 2005, we issued $230.0 million in 2¹/4% convertible subordinated notes due 2012 and in the fourth quarter of 2005, we repurchased all of the remaining outstanding subordinated notes due 2007. We may not be able to obtain additional financing on acceptable terms. If we raise additional funds by issuing equity securities, equity-linked securities or debt securities, the new equity securities may dilute the interests of our existing stockholders or the new debt securities may contain restrictive financial covenants.

Our need for additional funding will depend on many factors, including, without limitation:

	•		the amount of revenue, if any, that we are able to obtain from our collaborations, any approved products, and the time and costs required to achieve those revenues;

	•		the timing, scope and results of preclinical studies and clinical trials;

	•		the size and complexity of our development programs;

	•		the time and costs involved in obtaining regulatory approvals;

	•		the cost of launching our products;

	•		the costs of commercializing our products, including marketing, promotional and sales costs;

	•		our ability to establish and maintain collaboration partnerships;

	•		competing technological and market developments;

	•		the costs involved in filing, prosecuting and enforcing patent claims; and

	•		scientific progress in our research and development programs.

If we are unable to raise additional funds, we may, among other things:

	•		delay, scale back or eliminate some or all of our research and development programs;

	•		delay, scale back or eliminate some or all of our commercialization activities;

	•		lose rights under existing licenses;

	•		relinquish more of, or all of, our rights to product candidates on less favorable terms than we would otherwise seek; and

	•		be unable to operate as a going concern.

Our insurance policies are expensive and protect us only from some business risks, which will leave us exposed to significant, uninsured liabilities.

We do not carry insurance for all categories of risk that our business may encounter. We currently maintain general liability, property, auto, workers’ compensation, products liability and directors’ and officers’ insurance policies. We do not know, however, if we will be able to maintain existing insurance with adequate levels of coverage. For example, the premiums for our directors’ and officers’ insurance policy have increased over time, and this type of insurance may not be available on acceptable terms or at all in the future. Any significant uninsured liability may require us to pay substantial amounts, which would adversely affect our cash position and results of operations.

INTELLECTUAL PROPERTY RISKS

If patent laws or the interpretation of patent laws change, our competitors may be able to develop and commercialize our discoveries.

Important legal issues remain to be resolved as to the extent and scope of available patent protection for biotechnology products and processes in the U.S. and other important markets outside the U.S., such as Europe and Japan. Foreign markets may not provide the same level of patent protection as provided under the U.S. patent system. We expect that litigation or administrative proceedings will likely be necessary to determine the validity and scope of certain of our and others’ proprietary rights. We are currently involved in a number of administrative proceedings relating to the scope of protection of our patents and those of others. Any such litigation or proceeding may result in a significant commitment of resources in the future and could force us to do one or more of the following: cease selling or using any of our products that incorporate the challenged intellectual property, which would adversely affect our revenue; obtain a license from the holder of the intellectual property right alleged to have been infringed, which license may not be available on reasonable terms, if at all; and redesign our products to avoid infringing the intellectual property rights of third parties, which may be time-consuming or impossible to do. In addition, changes in, or different interpretations of, patent laws in the U.S. and other countries may result in patent laws that allow others to use our discoveries or develop and commercialize our products. We cannot assure you that the patents we obtain or the unpatented technology we hold will afford us significant commercial protection.

If our patent applications do not result in issued patents, our competitors may obtain rights to and commercialize the discoveries we attempted to patent.

Our pending patent applications, including those covering full-length genes and their corresponding proteins, may not result in the issuance of any patents. Our applications may not be sufficient to meet the statutory requirements for patentability in all cases or may be the subject of interference proceedings by the Patent and Trademark Office. These proceedings determine the priority of inventions and, thus, the right to a patent for technology in the U.S. We are involved in interference proceedings, including proceedings related to products based on TRAIL Receptor 2 (such as HGS-ETR2 and HGS-TR2J) and may be involved in other interference proceedings in the future. We are also involved in opposition proceedings in connection with foreign patent filings, including oppositions related to products based on BLyS (such as LymphoStat-B), and may be involved in other opposition proceedings in the future. We cannot assure you that we will be successful in any of these proceedings.

If others file patent applications or obtain patents similar to ours, then the Patent and Trademark Office may deny our patent applications, or others may restrict the use of our discoveries.

We are aware that others, including universities and companies working in the biotechnology and pharmaceutical fields, have filed patent applications and have been granted patents in the U.S. and in other countries that cover subject matter potentially useful or necessary to our business. Some of these patents and patent applications claim only specific products or methods of making products, while others claim more general processes or techniques useful in the discovery and manufacture of a variety of products. The risk of third parties obtaining additional patents and filing patent applications will continue to increase as the biotechnology industry expands. We cannot predict the ultimate scope and validity of existing patents and patents that may be granted to third parties, nor can we predict the extent to which we may wish or be required to obtain licenses to such patents, or the availability and cost of acquiring such licenses. To the extent that licenses are required, the owners of the patents could bring legal actions against us to claim damages or to stop our manufacturing and marketing of the affected products. We believe that there will continue to be significant litigation in our industry regarding patent and other intellectual property rights. If we become involved in litigation, it could consume a substantial portion of our resources.

Because issued patents may not fully protect our discoveries, our competitors may be able to commercialize products similar to those covered by our issued patents.

Issued patents may not provide commercially meaningful protection against competitors and may not provide us with competitive advantages. Other parties may challenge our patents or design around our issued patents or develop products providing effects similar to our products. In addition, others may discover uses for genes, proteins or antibodies other than those uses covered in our patents, and these other uses may be separately patentable. The holder of a patent covering the use of a gene, protein or antibody for which we have a patent claim could exclude us from selling a product for a use covered by its patent.

We rely on our collaboration partners to seek patent protection for the products they develop based on our research.

A significant portion of our future revenue may be derived from royalty payments from our collaboration partners. These partners face the same patent protection issues that we and other biotechnology firms face. As a result, we cannot assure you that any product developed by our collaboration partners will be patentable, and therefore, revenue from any such product may be limited, which would reduce the amount of any royalty payments. We also rely on our collaboration partners to effectively prosecute their patent applications. Their failure to obtain or protect necessary patents could also result in a loss of royalty revenue to us.

If we are unable to protect our trade secrets, others may be able to use our secrets to compete more effectively.

We may not be able to meaningfully protect our trade secrets. We rely on trade secret protection to protect our confidential and proprietary information. We believe we have acquired or developed proprietary procedures and materials for the production of proteins. We have not sought patent protection for these procedures. While we have entered into confidentiality agreements with employees and academic collaborators, we may not be able to prevent their disclosure of these data or materials. Others may independently develop substantially equivalent information and processes.

REGULATORY RISKS

Because we are subject to extensive changing government regulatory requirements, we may be unable to obtain government approval of our products in a timely manner.

Regulations in the U.S. and other countries have a significant impact on our research, product development and manufacturing activities and will be a significant factor in the marketing of our products. All of our products will require regulatory approval prior to commercialization. In particular, our products are subject to rigorous preclinical and clinical testing and other premarket approval requirements by the FDA and similar regulatory authorities in other countries, such as Europe and Japan. Various statutes and regulations also govern or influence the manufacturing, safety, labeling, storage, record keeping and marketing of our products. The lengthy process of seeking these approvals, and the subsequent compliance with applicable statutes and regulations, require the expenditure of substantial resources. Any failure by us to obtain, or any delay in obtaining, regulatory approvals could materially adversely affect our ability to commercialize our products in a timely manner, or at all.

Marketing Approvals. Before a product can be marketed and sold, the results of the preclinical and clinical testing must be submitted to the FDA for approval. This submission will be either a new drug application or a biologic license application, depending on the type of drug. In responding to a new drug application or a biologic license application, the FDA may grant marketing approval, request additional information or deny the application if it determines that the application does not provide an adequate basis for approval. We cannot assure you that any approval required by the FDA will be obtained on a timely basis, or at all.

In addition, the FDA may condition marketing approval on the conduct of specific post-marketing studies to further evaluate safety and efficacy. Rigorous and extensive FDA regulation of pharmaceutical products continues after approval, particularly with respect to compliance with current good manufacturing practices, or cGMPs, reporting of adverse effects, advertising, promotion and marketing. Discovery of previously unknown problems or failure to comply with the applicable regulatory requirements may result in restrictions on the marketing of a product or withdrawal of the product from the market as well as possible civil or criminal sanctions, any of which could materially adversely affect our business.

Foreign Regulation. We must obtain regulatory approval by governmental agencies in other countries prior to commercialization of our products in those countries. Foreign regulatory systems may be just as rigorous, costly and uncertain as in the U.S.

Because we are subject to environmental, health and safety laws, we may be unable to conduct our business in the most advantageous manner.

We are subject to various laws and regulations relating to safe working conditions, laboratory and manufacturing practices, the experimental use of animals, emissions and wastewater discharges, and the use and disposal of hazardous or potentially hazardous substances used in connection with our research, including radioactive compounds and infectious disease agents. We also cannot accurately predict the extent of regulations that might result from any future legislative or administrative action. Any of these laws or regulations could cause us to incur additional expense or restrict our operations.

OTHER RISKS RELATED TO OUR BUSINESS

Many of our competitors have substantially greater capabilities and resources and may be able to develop and commercialize products before we do.

We face intense competition from a wide range of pharmaceutical and biotechnology companies, as well as academic and research institutions and government agencies.

Principal competitive factors in our industry include:

	•		the quality and breadth of an organization’s technology;

	•		the skill of an organization’s employees and its ability to recruit and retain skilled employees;

	•		an organization’s intellectual property portfolio;

	•		the range of capabilities, from target identification and validation to drug discovery and development to manufacturing and marketing; and

	•		the availability of substantial capital resources to fund discovery, development and commercialization activities.

Many large pharmaceutical and biotechnology companies have significantly larger intellectual property estates than we do, more substantial capital resources than we have, and greater capabilities and experience than we do in preclinical and clinical development, sales, marketing, manufacturing and regulatory affairs.

We are aware of products in research or development by our competitors that address all of the diseases we are targeting. Any of these products may compete with our product candidates. Our competitors may succeed in developing their products before we do, obtaining approvals from the FDA or other regulatory agencies for their

products more rapidly than we do, or developing products that are more effective than our products. These products or technologies might render our technology or drugs under development obsolete or noncompetitive. In addition, our albumin fusion protein products are designed to be longer-acting versions of existing products. The existing product in many cases has an established market that may make the introduction of our product more difficult.

If we lose or are unable to attract key management or other personnel, we may experience delays in product development.

We depend on our senior executive officers as well as key scientific and other personnel. If any key employee decides to terminate his or her employment with us, this termination could delay the commercialization of our products or prevent us from becoming profitable. We have not purchased key-man life insurance on any of our executive officers or key personnel, and therefore may not have adequate funds to find acceptable replacements for them. Competition for qualified employees is intense among pharmaceutical and biotechnology companies, and the loss of qualified employees, or an inability to attract, retain and motivate additional highly skilled employees required for the expansion of our activities, could hinder our ability to complete human studies successfully and develop marketable products.

If the health care system or reimbursement policies change, the prices of our potential products may be lower than expected and our potential sales may decline.

The levels of revenues and profitability of biopharmaceutical companies like ours may be affected by the continuing efforts of government and third party payers to contain or reduce the costs of health care through various means. For example, in certain foreign markets, pricing or profitability of therapeutic and other pharmaceutical products is subject to governmental control. In the U.S. there have been, and we expect that there will continue to be, a number of federal and state proposals to implement similar governmental control. While we cannot predict whether any legislative or regulatory proposals will be adopted, the adoption of such proposals could have a material adverse effect on our business, financial condition and profitability. In addition, in the U.S. and elsewhere, sales of therapeutic and other pharmaceutical products depend in part on the availability of reimbursement to the consumer from third party payers, such as government and private insurance plans. Third party payers are increasingly challenging the prices charged for medical products and services. We cannot assure you that any of our products will be considered cost effective or that reimbursement to the consumer will be available or will be sufficient to allow us to sell our products on a competitive and profitable basis.

We may be unable successfully to establish a manufacturing capability and may be unable to obtain required quantities of our products economically.

We do not manufacture any products for commercial use and do not have any experience in manufacturing materials suitable for commercial use. We have completed construction and are in the validation phase of a large-scale manufacturing facility to increase our capacity for protein and antibody drug production. The FDA must inspect and license these facilities to determine compliance with cGMP requirements for commercial production. We may not be able successfully to establish sufficient manufacturing capabilities or manufacture our products economically or in compliance with cGMPs and other regulatory requirements.

While we are expanding our manufacturing capabilities, we have contracted and may in the future contract with third party manufacturers or develop products with collaboration partners and use the collaboration partners’ manufacturing capabilities. If we use others to manufacture our products, we will depend on those parties to comply with cGMPs, and other regulatory requirements and to deliver materials on a timely basis. These parties may not perform adequately. Any failures by these third parties may delay our development of products or the submission of these products for regulatory approval.

Because we currently have only a limited marketing capability, we may be unable to sell any of our products effectively.

We do not have any marketed products. If we develop products that can be marketed, we intend to market the products either independently or together with collaborators or strategic partners. GSK and others have co-marketing rights with respect to certain of our products. If we decide to market any products, either independently or together with partners, we will incur significant additional expenditures and commit significant additional management resources to establish a sales force. For any products that we market together with partners, we will rely, in whole or in part, on the marketing capabilities of those parties. We may also contract with third parties to market certain of our products. Ultimately, we and our partners may not be successful in marketing our products.

Because we depend on third parties to conduct some of our laboratory testing and human studies, we may encounter delays in or lose some control over our efforts to develop products.

We are dependent on third-party research organizations to design and conduct some of our laboratory testing and human studies. If we are unable to obtain any necessary testing services on acceptable terms, we may not complete our product development efforts in a timely manner. If we rely on third parties for laboratory testing and human studies, we may lose some control over these activities and become too dependent upon these parties. These third parties may not complete testing activities on schedule or when we request.

Our certificate of incorporation, bylaws and stockholder rights plan could discourage acquisition proposals, delay a change in control or prevent transactions that are in your best interests.

Provisions of our certificate of incorporation and bylaws, as well as Section 203 of the Delaware General Corporation Law, may discourage, delay or prevent a change in control of our company that you as a stockholder may consider favorable and may be in your best interest. We have also adopted a stockholder rights plan, or “poison pill,” that may discourage, delay or prevent a change in control. Our certificate of incorporation and bylaws contain provisions that:

	•		authorize the issuance of up to 20,000,000 shares of “blank check” preferred stock that could be issued by our board of directors to increase the number of outstanding shares and discourage a takeover attempt;

	•		classify the directors of our board with staggered, three-year terms, which may lengthen the time required to gain control of our board of directors;

	•		limit who may call special meetings of stockholders; and

	•		establish advance notice requirements for nomination of candidates for election to the board of directors or for proposing matters that can be acted upon by stockholders at stockholder meetings.

Because our stock price has been and will likely continue to be volatile, the market price of our common stock may be lower or more volatile than you expected.

Our stock price, like the stock prices of many other biotechnology companies, has been highly volatile. For the twelve months ended March 31, 2006, the closing price of our common stock has been as low as $7.75 per share and as high as $15.08 per share. The market price of our common stock could fluctuate widely because of:

	•		future announcements about our company or our competitors, including the results of testing, technological innovations or new commercial products;

	•		negative regulatory actions with respect to our potential products or regulatory approvals with respect to our competitors’ products;

	•		changes in government regulations;

	•		developments in our relationships with our collaboration partners;

	•		developments affecting our collaboration partners;

	•		announcements relating to health care reform and reimbursement levels for new drugs, particularly oncology drugs;

	•		our failure to acquire or maintain proprietary rights to the gene sequences we discover or the products we develop;

	•		litigation; and

	•		public concern as to the safety of our products.

The stock market has experienced extreme price and volume fluctuations that have particularly affected the market price for many emerging and biotechnology companies. These fluctuations have often been unrelated to the operating performance of these companies. These broad market fluctuations may cause the market price of our common stock to be lower or more volatile than you expected.

Beginning January 1, 2006 we are required to recognize expense for stock based compensation related to employee stock options and employee stock purchases, and there is no assurance that the expense that we are required to recognize measures accurately the value of our stock-based payment awards, and the recognition of this expense could cause the trading price of our common stock to decline.

On January 1, 2006, we adopted FASB Statement No 123(R), “Share-Based Payment” (“SFAS 123(R)”) which requires the measurement and recognition of compensation expense for all stock-based compensation based on estimated fair values. As a result, starting with fiscal year 2006, our operating results contain a charge for stock-based compensation expense related to employee stock options and employee stock purchases. The application of SFAS 123(R) requires the use of an option-pricing model to determine the fair value of stock-based payment awards. This determination of fair value is affected by our stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, our expected stock price volatility over the term of the awards, and actual and projected employee stock option exercise behaviors. Option-pricing models were developed for use in estimating the value of traded options that have no vesting or hedging restrictions and are fully transferable. Because our employee stock options have certain characteristics that are significantly different from traded options, and because changes in the subjective assumptions can materially affect the estimated value, in management’s opinion the existing valuation models may not provide an accurate measure of the fair value of our employee stock options. Although the fair value of employee stock options is determined in accordance with SFAS 123(R) and Staff Accounting Bulletin No. 107 (“SAB 107”) using an option-pricing model, that value may not be indicative of the fair value observed in a willing buyer/willing seller market transaction.

As a result of the adoption of SFAS 123(R), begin on January 1, 2006, our net loss is greater than it would have been had we not been required to adopt SFAS 123(R). This will continue to be the case for future periods. We cannot predict the effect that this change in our reported operating results will have on the trading price of our common stock.


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		Number
PART I.	FINANCIAL INFORMATION

Item 1.	Financial Statements

	Consolidated Statements of Operations for the three months ended March 31, 2006 and 2005		3

	Consolidated Balance Sheets at March 31, 2006 and December 31, 2005		4

	Consolidated Statements of Cash Flows for the three months ended March 31, 2006 and 2005		5

	Notes to Consolidated Financial Statements		7

Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations		15

Item 3.	Quantitative and Qualitative Disclosures about Market Risk		24

Item 4.	Controls and Procedures		25

PART II.	OTHER INFORMATION

Item 1a.	Factors That May Affect Our Business		26

Item 6.	Exhibits		38

	Signatures		39

	Exhibit Index	Exhibit Volume

	12.1		Ratio of Earnings to Fixed Charges.

	31i.1		Rule 13a-14(a) Certification of Principal Executive Officer.

	31i.2		Rule 13a-14(a) Certification of Principal Financial Officer.

	32.1		Section 1350 Certification of Principal Executive Officer.

	32.2		Section 1350 Certification of Principal Financial Officer.


		HUMAN GENOME SCIENCES, INC.

		BY:		/s/ H. Thomas Watkins

				H. Thomas Watkins
				Chief Executive Officer and President
				(Principal Executive Officer)

		BY:		/s/ Barry A. Labinger

				Barry A. Labinger
				Executive Vice President, Chief Commercial Officer and
				Chief Financial Officer (Principal Financial Officer)

12.1		Ratio of Earnings to Fixed Charges.

31i.1		Rule 13a-14(a) Certification of Principal Executive Officer.

31i.2		Rule 13a-14(a) Certification of Principal Financial Officer.

32.1		Section 1350 Certification of Principal Executive Officer.

32.2		Section 1350 Certification of Principal Financial Officer.