8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 28, 2011

OPTIMER PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware	001-33291	33-0830300
(State or other jurisdiction of	(Commission File Number)	(I.R.S. Employer
incorporation)		Identification No.)

10110 Sorrento Valley Road, Suite C
San Diego, California	92121
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (858) 909-0736

Not Applicable.

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.01Entry into a Material Definitive Agreement.

The disclosure in Item 2.01 below relating to the Amendment is hereby incorporated by reference into this Item 1.01.

Item 2.01Completion of Acquisition or Disposition of Assets.

Under the terms of our previously-announced financing agreement with Optimer Biotechnology, Inc. (“OBI”) and certain other investors, if OBI achieved certain milestones within a specified period of time, we and the other investors would have been required to purchase additional OBI shares at a subsequent closing (the “Second Closing”).  While the milestones set forth in the Financing Agreement were not fully achieved, in light of OBI’s recent filing of an investigational new drug application in Taiwan and initiation of a Phase 2/3 trial for OPT-822/821, we entered into an amendment to the Financing Agreement on February 28, 2011 (the “Amendment”) to hold the Second Closing.  Pursuant to the Amendment, the parties to the Financing Agreement completed the Second Closing on February 28, 2011 under the terms otherwise contemplated by the Financing Agreemen t, and OBI sold newly-issued shares of its common stock for total gross proceeds of 462.0 million New Taiwan Dollars (approximately $15.5 million based on then-current exchange rates).  We purchased 277.2 million New Taiwan Dollars (approximately $9.3 million based on then-current exchange rates) of the shares issued in the Second Closing and currently maintain our 60% equity interest in OBI.

The foregoing summary of the Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment, which is attached as Exhibit 99.1 hereto.

Item 9.01Financial Statements and Exhibits.

(d)Exhibits

Exhibit No.	Description
99.1	First Amendment to Financing Agreement, dated February 28, 2011.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	OPTIMER PHARMACEUTICALS, INC.
Dated: February 28, 2011	By:	/s/ John D. Prunty
		John D. Prunty
		Chief Financial Officer (Duly Authorized Officer
		and Principal Financial and Accounting Officer)

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Exhibit Index

Exhibit No.	Description
99.1	First Amendment to Financing Agreement, dated February 28, 2011.

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EX-99.1

Exhibit 99.1

OPTIMER BIOTECHNOLOGY, INC.

FIRST AMENDMENT TO FINANCING AGREEMENT

This FIRST AMENDMENT TO FINANCING AGREEMENT (this “Amendment”)  is made as of February 28, 2011, by and among OPTIMER BIOTECHNOLOGY, INC., a Taiwan corporation (the “Company”), and the undersigned party to that certain Financing Agreement, dated October 30, 2009 (the “Financing Agreement”), by and among the Company and the individuals and entities listed on the Schedule of Purchasers attached thereto.

RECITALS

WHEREAS, Section 6.6 of the Financing Agreement provides that the Financing Agreement may be amended with the written consent of the Company and the Majority Purchasers (as defined in the Agreement);

WHEREAS, the undersigned holds a sufficient number of Shares (as defined in the Financing Agreement) to constitute the Majority Purchasers; and

WHEREAS, the parties desire to amend the Financing Agreement as set forth herein.

NOW, THEREFORE, for good and valuable consideration, the sufficiency of which is hereby acknowledged, the parties hereto, including the Majority Purchasers on behalf of all Purchasers, hereby agree as follows:

1.  AMENDMENT AND RESTATEMENT OF SECTION 2.2 OF THE FINANCING AGREEMENT. Section 2.2 of the Financing Agreement is hereby amended and restated to read in its entirety as follows:

“2.2  Second Closing.  The second closing of the sale and purchase of the Shares under this Agreement (the “Second Closing”) shall take place on or about February 28, 2011, or at such other time as the Company and the Purchasers holding a majority of the Shares then issued hereunder (the “Majority Purchasers”) may mutually agree (the date on which the closing actually occurs is referred to herein as the “Second Closing Date”).  The Second Closing shall take place at 5:00 p.m. Pacific Time on the Second Closing Date at the offices of Cooley LLP, 4401 Eastgate Mall, San Diego, CA, 92121 or at such other place as the Company and the Majority Purchasers may mutually agree.  On the Second Closing Date, subject to the terms and conditions hereof, the Company will deliver to each Purchaser a certificate representing the number of Shares to be purchased at the Second Closing by such Purchaser, as set forth on the Schedule of Purchasers, against payment of the purchase price therefor by check or wire transfer made payable to the order of the Company, cancellation or conversion of indebtedness or any combination of the foregoing.  In the event that payment by a Purchaser is made, in whole or in part, by cancellation or conversion of indebtedness, then such Purchaser shall surrender to the Company for cancellation or conversion at the Second Closing any evidence of such indebtedness or shall execute an instrument of cancellation or conversion in form and substance acceptable to the Company.”

2.  COUNTERPARTS.  This Amendment may be executed in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

3.  GOVERNING LAW. This Amendment shall be governed by and construed under the laws of the State of California in all respects as such laws are applied to agreements among California residents entered into and performed entirely within California, without giving effect to conflicts of laws principles.

4.  NO OTHER AMENDMENT TO FINANCING AGREEMENT. Except as specifically amended by this Amendment, all other terms and conditions of the Financing Agreement shall remain in full force and effect in accordance with their terms without modification.

[Remainder of Page Intentionally Left Blank]

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IN WITNESS WHEREOF, the undersigned hereby executes this Amendment as of the date first above written.

OPTIMER BIOTECHNOLOGY, INC.
Signature:	/s/ Youe-Kong Shue, Ph.D
	Youe-Kong Shue, Ph.D.
	President & CEO
Address:	Room W1907, 19F
	3 Yuan Qu Street
	Nankang Software Park
	Taipei 115, Taiwan

[Signature Page to Amendment No. 1 to Financing Agreement]

IN WITNESS WHEREOF, the undersigned hereby executes this Amendment as of the date first above written.

MAJORITY PURCHASERS:
OPTIMER PHARMACEUTICALS, INC.
By:	/s/ John D. Prunty
Name:	John D. Prunty
Title:	Chief Financial Officer

[Signature Page to Amendment No. 1 to Financing Agreement]