SC TO-T/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO

(Rule 14d-100)

TENDER OFFER STATEMENT UNDER SECTION 14(d)(1)

OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 11)

OSI Pharmaceuticals, Inc.

(Name of Subject Company (Issuer))

Ruby Acquisition, Inc.

Astellas US Holding, Inc.

Astellas Pharma Inc.

(Name of Filing Persons (Offerors))

Common Stock, Par Value $.01 Per Share

(Including the Associated Stock Purchase Rights)

(Title of Class of Securities)

671040103

(CUSIP Number of Class of Securities)

Masafumi Nogimori

President and Chief Executive Officer

Astellas Pharma Inc.

3-11, Nihonbashi-Honcho

2-chome, Chuo-ku

Tokyo 103-8411, Japan

(81) 3-3244-3000

(Name, Address and Telephone Number of Person Authorized

to Receive Notices and Communications on Behalf of Filing Persons)

Copies to:

Michael O. Braun, Esq.

Craigh Leonard, Esq.

Morrison & Foerster LLP

1290 Avenue of the Americas

New York, New York 10104

(212) 468-8000

CALCULATION OF FILING FEE

Transaction Valuation*	Amount of Filing Fee**
$4,241,680,815	$302,432

* For purposes of calculating the amount of filing fee only in accordance with Rules 0-11(d) and 0-11(a)(4) under the Securities Exchange Act of 1934 (the “Exchange Act”). Based on the offer to purchase up to 73,768,362 shares of common stock, par value $0.01 per share of OSI Pharmaceuticals, Inc. (the “Company”), including the associated stock purchase rights, at a purchase price of $57.50 per share net to the seller in cash, without interest and subject to any required withholding of taxes. Such number of shares consists of (i) 61,201,595 shares of common stock issued and outstanding as of April 30, 2010, as represented in the merger agreement dated May 16, 2010 between the Company and the filing persons (the “Merger Agreement”), minus the 1,000 shares of common stock beneficially owned by the filing persons as of the date hereof, (ii) all options outstanding as of April 30, 2010 with respect to 5,681,575 shares of the Company’s common stock, as represented in the Merger Agreement, (iii) 3,920,201 shares of common stock issuable on the conversion of the $115,000,000 outstanding face amount of the Company’s 2% Convertible Senior Subordinated Notes due 2025, as represented in the Merger Agreement, and (iv) 2,965,991 shares of common stock issuable on the conversion of the $160,000,000 outstanding face amount of the Company’s 3% Convertible Senior Subordinated Notes due 2038, as represented in the Merger Agreement.

** The filing fee was calculated in accordance with Rule 0-11 under the Exchange Act, as amended, by multiplying the transaction value by .00007130.

x Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid: $270,211	Filing Party: Ruby Acquisition, Inc. Astellas US Holding, Inc. Astellas Pharma Inc.
Form or Registration No.: SC TO	Date Filed: March 2, 2010
Amount Previously Paid: $32,221	Filing Party: Ruby Acquisition, Inc. Astellas US Holding, Inc. Astellas Pharma Inc.
Form or Registration No.: SC TO-T/A	Date Filed: May 17, 2010

¨ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

x third-party tender offer subject to Rule 14d-1.

¨ issuer tender offer subject to Rule 13e-4.

¨ going-private transaction subject to Rule 13e-3.

¨ amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:  ¨

This Amendment No. 11 to Schedule TO (this “Amendment No. 11”) amends and supplements the Tender Offer Statement on Schedule TO as originally filed with the Securities and Exchange Commission on March, 2, 2010 (together with any amendments and supplements thereto the “Schedule TO”) relating to the offer by Ruby Acquisition, Inc. (“Purchaser”), a wholly-owned subsidiary of Astellas US Holding, Inc. (“Parent”), a wholly-owned subsidiary of Astellas Pharma Inc. (“Astellas”), to purchase all issued and outstanding shares of the common stock, par value $0.01 per share (the “Common Stock”, and together with the associated stock purchase rights, the “Shares”), of OSI Pharmaceuticals, Inc., a Delaware corporation (the “Company”), at a price of $57.50 per Share, net to the seller in cash, without interest and subject to any required withholding of taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated March 2, 2010 (together with any amendments and supplements thereto the “Offer to Purchase”) and in the related Letter of Transmittal, as amended or supplemented from time to time. This Amendment No. 11 is being filed on behalf of Astellas, Parent and Purchaser. You should read this Amendment No. 11 together with the Schedule TO. All capitalized terms used in this Amendment No. 11 and not otherwise defined have the respective meanings ascribed to them in the Offer to Purchase.

The information set forth in the Offer to Purchase, including Schedule I thereto, is hereby incorporated by reference in answer to Items 1 through 13 of this Schedule TO, and is supplemented by the information specifically provided herein.

Item 12. Exhibits

Item 12 of the Schedule TO is hereby amended and supplemented to add the following exhibits:

(a)(5)(Q)	Presentation regarding Astellas’ execution of a merger agreement with OSI Pharmaceuticals dated May 17 2010.
(a)(5)(R)	Transcript of audio presentation made by representatives of Astellas Pharma Inc on May 17, 2010.

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SIGNATURES

After due inquiry and to the best of their knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated May 18, 2010

ASTELLAS PHARMA INC.		ASTELLAS US HOLDING, INC.
By:	/s/    LINDA FRIEDMAN	By:	/s/    SEIGO KASHII
Name:	Linda Friedman as attorney-in-fact	Name:	Seigo Kashii
		Title:	Director, President & CEO
		RUBY ACQUISITION, INC.
		By:	/s/    SEIGO KASHII
		Name:	Seigo Kashii
		Title:	Director, President & CEO

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POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of Seigo Kashii, Linda F. Friedman and Stephen Knowles, individually and severally, and with full power of substitution, the undersigned’s true and lawful attorney-in-fact with full power to execute and file with the Securities and Exchange Commission and any stock exchange or similar authority, any report required to be filed pursuant to Section 14 of the Securities Exchange Act of 1934, (as amended, the “Act”), with respect to a third-party tender offer subject to Rule 14d-1, giving and granting unto said attorney-in-fact the power and authority to act in the premises as fully and to all intents and purposes as the Company might or could do if personally present by one of its authorized signatories, hereby ratifying and confirming all that said attorney-in-fact shall lawfully do or cause to be done by virtue hereof.

This Power of Attorney shall remain in full force and effect until the earliest of: (i) a revocation in writing by the undersigned; (ii) such time as the person to whom power of attorney has been hereby granted ceases to be an employee of the undersigned or any subsidiary company thereof; or (iii) March 2, 2011.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 2nd day of March, 2010.

ASTELLAS PHARMA INC.
By:	/s/    MASAFUMI NOGIMORI
Name:	Masafumi Nogimori
Title:	Director, President & CEO

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EXHIBIT INDEX

Exhibit No.	Description
(a)(1)(A)	Offer to Purchase dated March 2, 2010.*
(a)(1)(B)	Form of Letter of Transmittal.*
(a)(1)(C)	Form of Notice of Guaranteed Delivery.*
(a)(1)(D)	Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(1)(E)	Form of Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*
(a)(1)(F)	Guidelines for Certification of Taxpayer Identification Number on Substitute W-9.*
(a)(1)(G)	Summary Advertisement as published on March 2, 2010.*
(a)(5)(A)	Press Release issued by Astellas on March 1, 2010 incorporated herein by reference to the Schedule TO filed by Astellas on March 1, 2010.*
(a)(5)(B)	Press Release issued by Astellas dated March 2, 2010 regarding the commencement of the Offer and the lawsuit filed by Astellas US Holding, Inc. against OSI Pharmaceuticals, Inc.*
(a)(5)(C)	Complaint filed in Delaware Chancery Court against OSI Pharmaceuticals, Inc. and its directors.*
(a)(5)(D)	Letter regarding the Tender offer was distributed to certain public officials by Astellas.*
(a)(5)(E)	Press Release issued by Astellas dated March 15, 2010 regarding Astellas’ response to OSI Pharmaceuticals’ Rejection of its Offer.*
(a)(5)(F)	Press Release issued by Astellas dated March 16, 2010 regarding Astellas’ announcement of a full slate of independent director nominees for election at OSI Pharmaceuticals, Inc.’s 2010 Annual Stockholders Meeting.*
(a)(5)(G)	Press Release issued by Astellas dated March 19, 2010 regarding Astellas’ announcement of the expiration of the HSR waiting period for the Offer.*
(a)(5)(H)	Press Release issued by Astellas dated March 19, 2010 regarding Astellas’ announcement of changes to its director nominees for election to OSI Pharmaceuticals, Inc.’s Board of Directors.*
(a)(5)(I)	Press Release issued by Astellas dated March 29, 2010 regarding Astellas’ announcement of the execution of a confidentiality agreement with OSI Pharmaceuticals, Inc.*
(a)(5)(J)	Press Release issued by Astellas dated March 31, 2010 regarding Astellas’ announcement of the extension of the Offer.*
(a)(5)(K)	Presentation regarding Astellas’ offer to acquire OSI Pharmaceuticals dated April 2010.*
(a)(5)(L)	Press Release issued by Astellas dated April 23, 2010 regarding Astellas’ announcement of the extension of the Offer.*
(a)(5)(M)	Press Release issued by Astellas and OSI Pharmaceuticals dated May 16, 2010 announcing the execution of a Merger Agreement.*
(a)(5)(N)	Press Release issued by Astellas dated May 17, 2010 announcing the extension of the Offer.*
(a)(5)(O)	Astellas Pharma Inc. Letter to OSI Pharmaceuticals, Inc. Employees dated May 16, 2010.*

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(a)(5)(P)	Transcript of video presentation made by Masafumi Nogimori, Chief Executive Officer of Astellas Pharma Inc., to employees of OSI Pharmaceuticals on May 16, 2010.*
(a)(5)(Q)	Presentation regarding Astellas’ execution of a merger agreement with OSI Pharmaceuticals dated May 17 2010.
(a)(5)(R)	Transcript of audio presentation made by representatives of Astellas Pharma Inc on May 17, 2010.
(b)	Not applicable.
(d)(1)	Agreement and Plan of Merger, by and among Astellas Pharma Inc., Astellas US Holding, Inc., Ruby Acquisition, Inc. and OSI Pharmaceuticals, Inc., dated May 17, 2010*
(g)	Not applicable.
(h)	Not applicable.

* Previously filed with Schedule TO.

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EX-99.(A)(5)(Q)

Exhibit (a)(5)(Q)

Acquisition of OSI Pharmaceuticals, Inc.

Becoming a Global Category Leader in Oncology-May 17, 2010

Table of Contents

Transaction Summary

Strategic Rationale

Overview of OSI Pharmaceuticals

Financial Impact

2

I. Transaction Summary

3

Transaction Summary

Purchase price: $57.50 per share in cash (55% premium to the closing price on February 26, 2010, the last trading day before the announcement of tender offer)

Acquisition amount: Approximately $4.0 Billion (Fully diluted basis)

Tender offer period: Expires no later than 10 business days after the amendment to the Schedule TO is filed (which is expected to be filed on or before May 21st), unless extended

Financing: Fully financed with cash and cash equivalents on Astellas’ balance sheet

The acquisition is unanimously approved by the Board of Directors of both Astellas and OSI

4

II. Strategic Rationale

5

Business Model of Astellas

Global Category Leader (GCL)

A “GCL”, by providing value-added products “globally”, takes over the position of “leader” in a “category” where high unmet medical needs exist and a high degree of expertise is required.

6

Becoming a GCL in Oncology

Oncology, one of Astellas’ five focus therapeutic areas

Acquisition of OSI significantly enhances Astellas’ oncology capabilities

Current GCL Areas

Future GCL Candidates

Transplantation

Immunology

& Infectious Diseases

Urology

Oncology

Neuroscience

7

Strategic Rationale for OSI Acquisition

Accelerates development of Astellas’ oncology franchise

Acquire fully integrated oncology capabilities in the U.S. including discovery, development and commercialization

Expand clinical stage oncology pipeline

Access to small molecule discovery research platform in oncology

Existing revenue stream and improved profitability

Marketed blockbuster product with significant growth and late stage pipeline

Outstanding partnership with Roche/Genentech Growing DPP-IV royalty income

8

Fully Integrated Oncology Capabilities

OSI’s fully integrated oncology capabilities will complement Astellas’ oncology business strategy

Discovery & Clinical Development

Sales & Marketing

Astellas

Globally integrated R&D capabilities

with strong track records in urology,

immunology, etc.

Oncology: Highly prioritized area

(small molecule compounds and

antibodies)

Sales network in Japan, the Americas,

Europe and Asia

Experienced sales force in existing therapeutic areas, but not oncology

OSI

P

roven small molecule discovery research capabilities in oncology

Experienced sales representatives focused on oncology in the U.S.

9

Expand Clinical Stage Oncology Pipeline

Additions to Astellas’ oncology pipeline

Abtibody

Compounds Indication Phase 1 Phase 2 Phase 3

MDV3100 Prostate cancer(US/EU)

AC220 Acute myeloid leukemia(US/EU)

ASP3550 Prostate cancer(Japan)

YM155 Breast cancer, Non-Hodgkin’s lymphoma, Melanoma(US/EU/Japan)

AGS-1C4D4 Pancreatic cancer(US/EU)

ASP6183 (AGS-8M4) Ovarian cancer(US)

AGS-16M18 Cancer

AGS-16M8F Cancer

AGS-5ME Cancer

Tarceva® Adjuvant NSCLC, Ovarian cancer, Colorectal cancer(us)

(Extension) Other indications(US)

OSI-906 Adrenocortical Carcinoma(US)

OSI-906 Ovarian cancer(US)

OSI-930 Small cell lung cancer, Glioblastoma, Colorectal, renal, head and neck, non-small cell lung cancer, Gastric cancers

OSI-027 Advanced solid tumor, Lymphoma

10

Astellas Will Own Established Fully Integrated Oncology Platform

Acquisition of OSI provides established oncology platform that contributes to earnings and near-term product expansion potential

Compounds Status

Eligard® Marketed

Sma Mole MDV3100 Phase 3

AC220 Phase 2

Small Molecules ASP3550 Phase 2

YM155 Phase 2

AGS-1C4D4 Phase 2

ASP6183 (AGS-8M4) Phase 2

AGS-16M18 Phase 1

AGS-16M8F Phase 1

ASG-5ME Phase 1

Tarceva® Marketed

Tarceva® (Extension) Phase 2/3

ma ecu OSI-906 Phase 2/3

OSI-930 Phase 1

OSI-027 Phase 1

Timing of Launch (Illustrative)

Existing earnings and near-term product expansion expected

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III. Overview of OSI Pharmaceuticals

12

Overview of OSI Pharmaceuticals

Established in 1983 in the U.S., listed on NASDAQ

Based in Melville, NY with facilities in NY, CO, NJ in the U.S. and UK (U.S. facilities consolidating in Ardsley, NY by the end of 2010)

Company with unique, profitable, and fully integrated operations in discovery, development and commercialization of innovative molecular targeted therapies for the treatment of oncology, diabetes and obesity

Fully integrated oncology platform

Marketed lead product: Tarceva® (er/otinib, HER1/EGFR inhibitor)

Partnership with Roche/Genentech

Promising clinical pipeline in oncology and diabetes/obesity Robust financial performance with strong growth

Number of full-time employees: 512 (As of December 31, 2009)

13

Established Oncology Business Platform in the U.S.

A profitable and growing oncology business anchored around a blockbuster product with considerable remaining patent life (Tarceva®)

An experienced and capable commercial organization

A proven track record of success based on an established high quality drug discovery infrastructure and know-how

Discovery & Clinical Development

Sales & Marketing

14

Tarceva®—A Blockbuster Oncology Drug

One of the most successful oncology products in terms of patients treated in U.S. history

Achieved ~$1.2billion of worldwide sales in 2009

Approved for sale in 109 countries for treatment of advanced

non-small cell lung cancer (NSCLC) Strategically valuable long-term cash flows throughout

exclusivity period

Life cycle plan

Life cycle plan expected to yield multiple data and label

expansion opportunities EGFR-mutation and ovarian cancer milestones expected over

the next 15 months Additional opportunities in liver cancer and multiple molecular

targeted therapy combination trials

15

Tarcevafft Life Cvrle Plan

2004 2005 2006 2007 2008 2009 2010

NSCLC 2L / 3L Approval Pancreatic Cancer 1L Approval

NSCLC 1L Maintenance / EGFR Mutation (SATURN) / CALGB Data

Ovarian Cancer 1LM (EORTC) P-3 Data

NSCLC 1L EGFR-Mt (EURTAC) P-3 Data Multiple data and

NSCLC Adjuvant (RADIANT) P-3 Data

HCC 1L (SEARCH) P-3 Data opportunities

NSCLC T+OSI-906 P-3 Data

16

Clinical Pipeline

Compounds Characteristics Indication Status

Oncology

Tarceva® (erlotinib) (Extension) HERl/EGFR tyrosine kinase inhibitor Adjuvant NSCLC, Ovarian cancer, Colorectal cancer Other indications Phase 3 Phase 2

OSI-906 IGF-1R/IR tyrosine kinase inhibitor Adrenocortical Carcinoma Ovarian cancer Phase 3 Phase 2

OSI-930

(Out-licensed to Simcere Pharma in China) c-kit/VEGFR-2 tyrosine kinase inhibitor Small cell lung cancer, glioblastoma, Colorectal, renal, head and neck, non-small celt lung cancer, Gastric cancers Phase 1

OSI-027 mTOR kinase inhibitor Advanced solid tumor, lymphoma Phase 1

Diabetes / Obesity

PSN821 GPR119 agonist Type 2 diabetes / obesity Phase 2

PSN010

(Out-licensed to Eli Lilly) Glucokinase activator Type 2 diabetes Phase 2

17

Discovery Capabilities

Focus on novel targets with biological validation

Has multiple small molecule based drug discovery programs in

both oncology and diabetes / obesity that employ both

traditional and novel assays Drug targets are predominantly kinase pathways that are

either clinically validated or validated through extensive

elucidation of the biology and role in disease Competitive edge is targeting multiple pathways and in

selectivity of drug candidates / Novel cell based assay (EMT—Epithelial-Mesenchymal

Transition) is unique in the industry

Oncology research in the U.S., diabetes / obesity research through a subsidiary in the UK

18

Robust Financial Performance with Strong Growth

• OSI is growing in both revenue and profit

Revenue

Operating Income

From Continuing Operations

(US$ millions)

450 -

400 -

350 -

300 -

250 -

200 -

150 -

100 -

50 -

341

CAGR: 12.0%

379

428

180

160

140

120

100

80

60

40

20

97

133

153

2007

2008

2009

2007

2008

2009

CAGR: Compound Annual Growth Rate during 2007-2009 Source: OSI’s filings

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IV. Financial Impact

20

Financial Impact

Financial impact shown below is based on currently available information

Details of the impact will be announced once finalized

(Unit: Billion Yen)

FY2014

FY2010* Revenue

34

Operating income before amortization estimated to be accretive from

year 1

Operating income before amortization of assets

Operating income after amortization of assets

(17)

* 9-month impact assumed in FY2010

21

Additional Information

Further details related to this announcement can be found on www.oncologyleader.com

Media Contacts

Brunswick New York +1 212 333 3810 Stan Neve Sarah Lubman

Brunswick Hong Kong +852 9850 5033 Joseph Lo

Information Agent Georgeson

+ 1 212 440 9872 Thomas Gardiner

About Astellas

Astellas Pharma Inc., located in Tokyo, Japan, is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable Pharmaceuticals. Astellas has approximately 15,000 employees worldwide. The organization is committed to becoming a global category leader in urology, immunology & infectious diseases, neuroscience, DM complications & metabolic diseases and oncology. For more information on Astellas Pharma Inc., please visit our website at http://astellas.com/en.

About OSI Pharmaceuticals

OSI Pharmaceuticals, Inc. is committed to “shaping medicine and changing lives” by discovering, developing and commercializing high-quality, novel and differentiated targeted medicines designed to extend life and improve the quality of life for patients with cancer and diabetes/obesity. For additional information about OSI, please visit http://www.osip.com.

Important additional information

This press release is for informational purposes only and does not constitute an offer to purchase or a solicitation of an offer to sell OSI’s common stock. The tender offer (“Tender Offer”) is being made pursuant to a tender offer statement on Schedule TO (including the offer to purchase, letter of transmittal and other related tender offer materials) initially filed by Astellas with the Securities and Exchange Commission (the “SEC”) on March 2, 2010. These materials, as they may be amended from time to time, contain important information, including the terms and conditions of the offer, that should be read carefully before any decision is made with respect to the Tender Offer. Investors and shareholders can obtain a free copy of these materials and other documents filed by Astellas with the SEC at the website maintained by the SEC at www.sec.gov. The Tender Offer materials may also be obtained for free by contacting the information agent for the tender offer, Georgeson Inc. at (212) 440-9800 for banks and brokers and at (800) 213-0473 for persons other than banks and brokers.

OSI’s stockholders should read the company’s solicitation/recommendation statement on schedule 14D-9, which was initially filed with the SEC on March 15, 2010, and any amendments or supplements thereto. The company’s solicitation/recommendation statement will set forth the reasons for the recommendation of the OSI’s board and related information. The solicitation/recommendation statement and other public filings made from time to time by OSI with the SEC are available without charge from the SEC’s website at www.sec.gov, at OSI’s website at www.osip.com or from OSI’s information agent, MacKenzie Partners, Inc. by calling 800-322-2885 (toll free) or 212-929-5500 or by emailing osipharma@mackenziepartners.com.

Statement of Cautionary Factors

This document contains certain forward-looking statements. These forward-looking statements may be identified by words such as ‘believes’, ‘expects’, ‘anticipates’, ‘projects’, ‘intends’, ‘should’, ‘seeks’, ‘estimates’, ‘future’ or similar expressions or by discussion of, among other things, strategy, goals, plans or intentions. Various factors may cause actual results to differ materially in the future from those reflected in forward-looking statements contained in this document, among others: (1) pricing and product initiatives of competitors; (2) legislative and regulatory developments and economic conditions; (3) delay or inability in obtaining regulatory approvals or bringing products to market; (4) fluctuations in currency exchange rates and general financial market conditions; (5) uncertainties in the discovery, development or marketing of new products or new uses of existing products, including without limitation negative results of clinical trials or research projects, unexpected side-effects of pipeline or marketed products; (6) increased government pricing pressures; (7) interruptions in production; (8) loss of or inability to obtain adequate protection for intellectual property rights: (9) litigation; (10) loss of key executives or other employees; and (11) adverse publicity and news coverage. The statement regarding earnings growth is not a profit forecast and should not be interpreted to mean that Astellas’ earnings or earnings per snare for any current or future period will necessarily match or exceed the historical published earnings or earnings per share of Astellas.

EX-99.(A)(5)(R)

Exhibit (a)(5)(R)

The Following is a transcript of the conference call given by representatives of Astellas Pharma Inc. on May 17, 2010:

Astellas Pharma M&A/Other Teleconference 4503 JP

2010-05-17 14:20:33.145 GMT

Event Date: 05/17/2010

Company Name: Astellas Pharma

Event Description:Acquisition of OSI Pharmaceuticals, Inc. by Astellas Pharma, Inc. Call

Source: Astellas Pharma

MANAGEMENT DISCUSSION SECTION

Operator:

Ladies and gentlemen I thank you very much for participating our telephone conference to announce the merger - acquisition of OSI Pharmaceuticals by Astellas.

Let me introduce the participants, Mr. Nogimori, the President and CEO; and Mr. Toichi Takenaka, the Vice Corporate Executive and Corporate Executive VP, Corporate Finance and Control Mr. Masuda, and VP Licensing and Alliance Mr. Yokota. [ph] My name is Mr. Kumura , VP of Corporate of Communications. Before giving you the explanation into the conference call, there might be a chance that we may - we are going to give our forward-looking information but this is an just estimate by the company. And due to the various factors, our future - our forecasts might entirely different from the information that may be delivering it you in this conference call.

So I would like to ask Mr. Nogimori to take it over from here.

Masafumi Nogimori, President and Chief Executive Officer:

My name is Nogimori, the President and CEO of Astellas. Despite a very busy schedule thank you very much for attending this conference call to give you the announcement about acquisition by Astellas of OSI Pharmaceuticals, the U.S. a pharmaceutical company. As was released in today’s press release we have reached an agreement about the acquisition between OSI and I am very delighted to be able to report this to you.

As so we have been disclosing to you through our U.S. subsidiary we have started the TOD on March 2, the U.S. time to acquire the OSI common stock of cash of $52 per share. And after that on U.S. Time March 29, we concluded a NDA with OSI and by getting the known disclosing information we executed very detail due diligence and we have carried out a number of negotiations and with that we were able to achieve - agreed on the acquisition this time.

The tender price or $57.5 per share, that we reached agreement this time has taken into account of net long-term enterprise value of OSI and we believe that this is appropriate pricing.

Astellas has long-term management vision of Vision 2015 and in this vision, we are trying to materialize to be come to global category and with oncology area to be the appropriate franchise and we have been adversely pursuing to build the platform in this area. And by acquiring OSI this time, we will be able to accelerate the development of oncology area and also at the same time we will be able to further enhance that our product portfolio and development pipeline.

Furthermore, in addition to the cancer franchise platform owned OSI, the drug discovery platform and human resources which was owned by the OSI to be integrated with the Astellas existing business, with that we will be able to maximize the value of two company’s management resources and that would enable to enhance the growth strategy.

1

In addition to this mid-to-long term growth, through the sales of world-leading oncology treatment Tarceva we believe that this will contribute to our earnings from the early stage and this will contribute to the big improvement of our enterprise value. So in Astellas, the growth strategy, the acquisition of OSI has a very significant meaning. And in concluding the definitive merger agreement, I’m very delighted to be able to obtain the approval from the OSI Board of Directors so that we would be able to pursue this acquisition in a very friendly manner and believe that this friendly acquisition will play a very important role in the future our growth strategy for the company. So we would like to refer to the materials from now on. As you can see from the agenda on page two, I will like to explain the transaction summary, strategic rationale, the overview of OSI, and impact to the financials.

So, first of all, please take a look at page four. In this slide, I’m going to explain about the overview of the transaction. The purchase price is $57.5 per share and this is going to be 55% premium to the closing price of February 26, 2010, which is the last trading day before the tender offer announcement. And for acquisition amount, it will be about $4 billion after fully diluted basis. And for the tender offering period, after we file the amended Schedule TO to US SEC, it’s going to be extended up to 10 working days. And for the acquisition amount, we are going to be financed fully by cash on our hand.

And as you can see from page six, Astellas is pursuing to become the global category leader as mentioned in vision 2015. In other words, in the multiple contract categories, which requires that this by a high level of specialties as well as the high unmet medical needs by offering the high value-added products globally, we are trying to become the leader of the category by building the competitive edge.

Please take a look at page seven, as you can see, our company is focusing on those five areas, but we are falling under transplantation and urology, we are working to - and oncology to be the number three areas for us to become the global category leader. So by acquiring OSI, in addition to the US existing - both ideas existing - Astellas existing business in the US by adding the OSI’s US oncology area, we will be able to have a very big step forward in becoming the global category leader in oncology area.

In page eight, as I have mentioned at the beginning, it is very important for us to acquire OSI in terms of a strategic meaning. The biggest important thing here is that by acquiring OSI company’s cancer business platform can be developed early. In other words, by acquiring OSI, we will be able to obtain the cancer platform which already has the drug discovery development and commercialization. But on top of that, we will be able to have affluent pipeline of the oncology area, and at the same time we will be able to obtain the small molecule compound discovery research platform, which discovered the placebo the blockbuster drug. And furthermore, OSI acquisition will be establishing revenue source and at the same time we are expecting to have this to improve our profitability as well as the growth. And that not only the placebo expansion of the label can be expected to see the future growth coming from the late stage development program from OSI. In oncology area, the partnership that OSI has with global leader Roche in oncology area and also Genentech in Europe, this partnership will not change. And by doing so by developing Tarceva, we will be able to obtain their knowledge and know-how in oncology area. And finally, for the OSI DPP-IV inhibitor, the royalty income from that we will be able to expect further increase from this royalty income and due to the success of this drug as well as expansion of the market in the diabetic areas.

Please take a look at page nine. We have very integrated R&D organization globally in various disease areas and we think we are trying to enhance our oncology areas by leveraging our in-house resources as well as acquisition. By having OSI leading platform on top of it, we will be able to further strengthen this and Astellas is currently having our own sales network in Japan, the US, Europe and Asia, but acquiring OSI will enable to have — enabled for us to be able to own the U.S oncology Astellas network at once. Please take a look at page 10. Our company in order to expand the oncology pipeline we had been investing our management resources with OSI pipeline that will be further enhanced. In only Tarceva we will be able to obtain the three new small molecule targeted candidate compounds which we are considering to have a indication to multiple cancers.

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Page 11, please. As I explained in the previous page, we have many anti-tumor pipeline assets. By the acquisition of OSI, we have the marketed products already strongly based in U.S. oncology market and we have very strong sales channel as we tried to continuously develop price line assets. OSI has a proven track record of very strong sales and we can effectively launch new products. I have explained the outline of the acquisition in the strategic significance for Astellas. Now, let me explain OSI business profile.

Page 13, please. OSI was established in 1983 in U.S. Now they have — they’re based in Melville in New York and they have facilities in Colorado, New Jersey and in U.K. The facilities in U.S. will be consolidated by the end of this year through largely in New York State.

In oncology, diabetes and obesity areas, OSI covers innovative molecular targeted therapies from discovery to development and commercialization in an integrated manner. It is a unique and profitable biotech company. Major project, Tarceva is a blockbuster indicated for non-small cell lung cancer. It also has very promising development pipeline assets in oncology, diabetes and obesity. Also performance is very positive and we can expect strong growth.

Further more, page 14, please. As I stated, OSI has established oncology platform in U.S. and its blockbuster Tarceva has considerable patent life remaining.

In oncology, they have experienced and capable sales reps and they have the experience of successfully launched Tarceva and they have the quality drug discovery infrastructure and know how.

Page 15. It summarizes the main project Tarceva and anti-tumor agents. Tarceva is one of the most successful oncology products in terms of number of patients treated in U.S. history, 2009 it achieved $1.2 billion in sales worldwide to treat non-small cell lung cancer and it is approved and marketed in 109 countries worldwide. Also they have a very strong life cycle management plan. In April, FDA approved indication for maintenance therapy and we expect additional opportunities in expansion of indications. Page 16, explains Tarceva’s life cycle management and potential for — of our next few years. It also shows expected trial data timing. Page 17, OSI’s development pipeline is summarized here. In addition to indication expansion of Tarceva, there are three candidates for oncology area, OSI-906, is Phase 3 for adrenocortical carcinoma and for ovarian cancer it is in Phase 2. OSI-930 is now in Phase 1onsidering various cancer types. OSI-027 is for solid cancer and lymphoma in Phase 1 trials are ongoing.

Next is OSI subsidiary based in UK Prosidion based pipeline assets in diabetes and obesity PSN821 is for Type 2 diabetes and obesity. And also for PSN010 is licensing out to Eli Lilly and Phase 2 studies are ongoing for Type 2 diabetes.

Page 18, among various assets earned by a) OSI, one thing that we appreciate very highly is OSI’s discovery capability. OSI focuses on not our targets with biological validation in the areas of oncology, diabetes and obesity, multiple small molecule programs are being explored. As I said before, drug discovery for oncology is U.S based and for diabetes and obesity it is based for in U.K, and their subsidiary proceed on.

Page 19, strong business platform is reflected in the robust financial performance. Sales from 2007 grew 12% on average and in 2009 $428 million was reached. Operating income, thanks to OSI’s business model we can expect even higher growth. In future, we have new products coming into the market therefore we expect very good growth for years to come.

Lastly, Page 21, financial impacts on a consolidated basis will be explained, the numbers shown on this page is based on the information currently available depending on OSI’s future performance and accounting treatment of consolidation basis, it is subject to change. And regarding the impacts on the consolidated result after integration will be announce to you when we have the update, and final numbers. For FY 2010, we considered nine months impact from July to March next year, as sales impact positive 34 billion of IT income before amortization will have 14 billion positive impacts, and after amortization minus 16 billion.

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For FY 2011 and beyond, we expect OSI’s business to grow further more as shown in this graph up to 2014 last year of mid-range plan to be announced next week, we expect that sales operating income will grow annually. So that was my presentation, regarding OSI acquisition.

As I said in the beginning for Astellas to be the global category leader in oncology this acquisition is a major step. By maximizing the value of our management resource of Astellas in OSI, we want to make sure that our gross is secured, and we will do our best for that. Thank you very much.

Company Representative:

Thank you very much. That will be all from the explanation from Astellas. So we’ll like to take question from the participants.

Q&A

<Q>: This question is from Schroeder, Sato [ph]. I have two questions. So about the revision to this tender price with this due diligence and I understand that evaluation of price has gone up and if there is such then we would like to know the factor for that, and also if you were to propose to the execution then please let us know about that. And on Page 21, impact to the profit and loss that is operating profit linear line, there are two lines there. So about this yellow line that is mentioned in there in a - I think second half of 2012 or the first half of 2013 it looks that you are going to go beyond at breakeven point. Is that my understanding correct?

<A - Toichi Takenaka>: So, this is Toichi Takenaka. So, let me I will give you - let me respond to your question. The first question about the revision to our tender price, well as you’ve known at the end of March with OSI, we concluded a NDA and after that we got the known disclosed information from them and since then, the changes that happened by the first align indication acquisition of our placebo and other we have revised everything and we revalued. So, about the execution possibility, it is — this is not the factor that makes us the way this is tender offer price. And your secondquestion as our President had mentioned, as based on the estimates that we already have in a third year or on the fourth year after amortization, our operating across that would turn to that, so that’s the estimation that’s we currently have. So, for estimation or the forecast that we have — so to further looking to the details and also to correct by the accounting process, we might be able to give you our more specific numbers later. About the first indication on placebo did you not include that information to your first evaluation first attender of price at all or did you not include 100% of that of first line from the very beginning for the maintenance indication of the placebo we have put some value for that. So, after that first line indication was finalized first you put 100% of that value into your attender offer is that correct?

<A>: No. After looking to various stages we had new value to that.

<Q>: That’s all from me. Thank you very much.

Operator:

Mr. Yamaguchi from Citigroup. Go ahead.

<Q - Hidemaru Yamaguchi>: Hello, Yasuo Ishii, yes we do. About the structure mechanism regarding anti cancer driver you now have the growth driver for oncology in combination with your existing products and pipeline and business decision how do you make decision where and who. So as of now U.S OSI may play a major role there. So regarding OSI franchise to be leveraged for your process in the integration so what’s the decision making process?

<A - Masafumi Nogimori, President and Chief Executive Officer>: This is now Nogimori speaking. Let me answer to that question, regarding the question of decision-making especially about the pipeline asset, well, about how we move forward, we will be discussing together with OSI as of now. Our R&D base is in Chicago and OSI in the Chicago base facility will be very much in coordination as we move forward.

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<Q - Hidemaru Yamaguchi>: Thank you. Thus next is my second question, regarding impact of finance 14 billion and 17 billion together, 31 billion and that is for nine months divided by nine and about 40 billion calculation is the annual amortization, is that correct?

<A>: I think that’s more or less right. For FY 2014, the scale is the same as for FY 2010 where we did not precisely measure the scale this is based on our currently available information this is a schematic concept. One thing we can say is operating income before amortization we expect the results that is what we can answer to you at present. Thank you very much.

Operator:

The next question is from Masuzoe Kenji from Deutsche Securities.

<Q - Kenji Masuzoe>: This is Masuzoe Kenji speaking. I have a number of questions. But the first question is that, the cash going forward, so you mentioned that it is a period of tender is going to extended by 10 working days about 90% 80% will be okay, but going forward, how do you this deal will proceed going forward?

<A - Toichi Takenaka>: This is Takenaka speaking. So in order for us to subsidy in this transaction, we need to obtain more than 50% of the earnings stock. So what we are going to do going forward is to make sure that we obtain more than 50% and of course more than 50% and less than 90% and as they impact, then we need to go to the shareholders’ meeting to make this transaction successful. And another point, if we were to be able to obtain more than 90% of the outstanding shares, then this will be the discretion. We need to just get the approval from the Board of Directors. So this will be a simplified version. So we’re not in a position to make a comment about this, but the price that we agreed with OSI is carried OSI to mid-term enterprise as that improvement reflected and to OSI shareholders, they will be able to turn their value into cash immediately. So I believe that this deal is quite good appealing for the shareholders of OSI as well.

<Q - Kenji Masuzoe>: And if you can be successful then your efforts seems to be able to integrate starting from July this year?

<A>: Yes, that is correct. So that’s essential for us in creating these numbers.

<Q - Kenji Masuzoe>: So your mentioned that this is going to be a friendly TOB [ph], but can I understand that the current OSI management people will remain for next one year or one and a half year, I don’t know, but would that be the condition for this transaction?

<A - Toichi Takenaka>: This is Takenaka speaking, including that point, how we’re going to go to the integration process between OSI and Astellas, that will depend upon the discussion that we’re going to have going forward. So at this point in time, I’m not in a position to give you the detailed information.

<Q - Kenji Masuzoe>: As we see [ph] OSI, would you be able to see some cost synergy coming from there?

<A>: Well, in January 10, we can expect that to happen. But as was mentioned by Mr. Nogimori, we put importance to the strategic side of it. We do not put a lot of importance to the cost synergy in going through this acquisition.

<Q - Kenji Masuzoe>: Last question, next week you’re planning to announce your mid-term business plans, but you will not be able to include this transaction into your mid-term business plan in terms of number, is that correct?

<A>: Well, of course, we are putting our efforts right now. But slide 21, as far as we can do is to incorporate and say to anyone into the existing efforts that we have for the mid-term business plan. That’s maybe as far as we can do.

Operator:

Next question is from Credit Suisse, Mr. Sakai. Mr. Sakai, go ahead. Hello?

<Q - Fumiyoshi Sakai>: I have two, three questions. As of 22 April, Astellas acquired 42,283 shares, can you figure this to change from the number of shares that you have acquired since that time?

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<A - Toichi Takenaka>: This is Takenaka speaking. In today’s press release that at the end of New York Time 14 of May 299,114 shares were listed. Thank you very much.

<A>: Thank you.

<Q - Fumiyoshi Sakai>: First quarter of OSI is already released. On the fees associated with acquisition to be paid at and I suppose financially it has done negative impact as a guidance on the other hand to 500 million for sales, that was the estimate if integration moves in July then the first quarter and the second quarter of OSI, how would that be treated?

<A - Yasumasa Masuda>: This is Masuda speaking. Let me talk regarding the accounting treatment. Well, OSI as you know is based on calendar year for their financial closing whereas Astellas April to March. So if more than 50% of shares obtained by the first of July then on that assumption the sales from July would be added to our accounting and OSI fiscal year, how that is to be established, we have not had the final answers, but they will be treated in line with Astellas’ rule and accounting. Is that all right?

<Q - Fumiyoshi Sakai>: Okay. Thank you very much. So the closing may

change?

<A - Yasumasa Masuda>: That is a possibility. As the great management it is preferable to have the same closing timing so that would be an issue we would discuss.

<Q - Fumiyoshi Sakai>: Thank you. That’s all.

Operator:

There is no further question, so we would like to stop Q&A.

Company Representative:

Thank you very much for participating to the conference call today and I hope that you would support our company going forward as well. Thank you very much.

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