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

June 3, 2010

Date of Report (Date of earliest event reported)

OSI Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware	0-15190	13-3159796
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

420 Saw Mill River Road

Ardsley, NY 10502

(Address of principal executive offices)

(914) 231-8000

(Registrant's telephone number, including area code)

N/A

(Former name or former address,

if changed since last report.)

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

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

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

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

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

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ITEM 2.04 Triggering Events That Accelerate or Increase a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement.

The consummation of the Company Change in Control (as defined below) on June 3, 2010 and the consummation of the Merger (as defined below) on June 8, 2010 each constituted a "Fundamental Change" under the Indentures (the "Indentures") between OSI Pharmaceuticals, Inc. (the "Company") and The Bank of New York Mellon relating to Company's 2% Convertible Senior Subordinated Notes Due 2025 (the "2025 Notes") and 3% Convertible Senior Subordinated Notes Due 2038 (the "2038 Notes", and together with the 2025 Notes, the "Convertible Notes").  As a result, holders of the Convertible Notes have the right (1) to require the Company to repurchase their Convertible Notes at their principal amount plus accrued and unpaid interest on a certain date (the "Fundamental Change Purchase Date") as set forth in the Indentures or (2) 0;to convert their Convertible Notes pursuant to the applicable Indenture for cash at the then applicable conversion rate, as may be adjusted under the applicable Indenture.  The Fundamental Change Purchase Date for the Convertible Notes in connection with the Company Change in Control is July 16, 2010.  The Fundamental Change Purchase Date for the Convertible Notes in connection with the Merger is July 21, 2010.  Assuming that each holder of Convertible Senior Notes elected to convert its Convertible Notes, the Company would be obligated to make aggregate payments of approximately $408 million.  On June 4 and June 9, 2010, the Company issued press releases announcing the Fundamental Changes under the Indenture governing the 2025 Notes, which press releases are attached hereto as Exhibits 99.1 and 99.2, respectively.

ITEM 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule of Standard; Transfer of Listing.

In connection with the completion of the Merger, on June 8, 2010, the Company notified The NASDAQ Stock Market ("NASDAQ") that the Merger had been completed and requested that NASDAQ file a delisting notification on Form 25 with the Securities and Exchange Commission (the "SEC") to delist the Company's common stock, par value $.01 per share (the "Common Stock") and terminate the registration of the Common Stock under Section 12(b) of the Securities Exchange Act of 1934, as amended, which NASDAQ filed with the SEC on June 8, 2010.  Trading of the Common Stock on The NASDAQ Global Select Market was suspended following the close of the NASDAQ trading session on June 8, 2010.

ITEM 3.03 Material Modification to Rights of Security Holders.

The disclosure contained in Items 2.04 and 5.01 of this Report is incorporated by reference into this Item 3.03.

ITEM 5.01 Changes in Control of Registrant.

As previously disclosed, on May 16, 2010, the Company entered into an agreement and plan of merger with Astellas Pharma Inc., a corporation formed under the

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laws of Japan ("Astellas"), Astellas US Holding, Inc. ("Parent"), a Delaware corporation and wholly-owned subsidiary of Astellas and Ruby Acquisition, Inc. ("Merger Sub"), a Delaware corporation and wholly-owned subsidiary of Parent (as amended by the First Amendment to the Agreement and Plan of Merger, dated June 3, 2010, by and among Astellas, Holding, Merger Sub and the Company, the "Merger Agreement"), pursuant to which, among other things, Astellas amended its existing offer to purchase all of the issued and outstanding shares of the Company's Common Stock, including the associated rights to purchase shares of Series SRP Junior Participating Preferred Stock, par value $0.01 (the "Rights", and together with the Common Stock, the "Shares"), to offer cash consider ation of $57.50 per Share (the "Offer Price"), without interest (as amended, the "Offer").

On June 3, 2010, Astellas announced that the initial offering period had expired at midnight, New York City time, on June 2, 2010 and that it had commenced a subsequent offering period for all remaining untendered Shares, which expired at midnight, New York City time, on June 7, 2010.  The depositary for the Offer advised Astellas that a total of 48,415,727 Shares were validly tendered and not withdrawn prior to the expiration of the initial offering period and 4,190,714 Shares were tendered through guaranteed delivery procedures, representing an aggregate of 52,606,441 Shares or approximately 86% of the Company's issued and outstanding Shares.  All Shares that were validly tendered in the initial offering period and not withdrawn were accepted for payment by Merger Sub.  Upon the acceptance of Shares for payment pursuant to the Offer on June 3, 2010 (the "Acceptance Time"), a change of control of the Company occurred (the "Company Change in Control"). The depositary for the Offer advised Astellas that an additional 4,625,916 Shares were validly tendered prior to the expiration of the subsequent offering period, which, together with the Shares tendered in the initial offering period, represented approximately 93% of the Company's issued and outstanding Shares.  All Shares that were validly tendered in the subsequent offering period were immediately accepted for payment by Merger Sub.

On June 8, 2010, pursuant to the terms of the Merger Agreement and in accordance with Section 253 of the General Corporation Law of the State of Delaware (the "DGCL"), Merger Sub was merged by way of a "short-form" merger (the "Merger") with and into the Company with the Company surviving the Merger as a wholly owned subsidiary of Holding without a vote of the Company's stockholders.  At the effective time of the Merger (the "Effective Time"), each Share issued and outstanding immediately prior to the Effective Time (other than Shares held by the Company, Astellas, Holding, Merger Sub or stockholders who are entitled to demand and properly perfect appraisal rights under the DGCL) was converted into the right to receive the Offer Price, without interest.

The total amount of funds necessary to complete the Offer and the Merger was approximately $4 billion.  Certain of the expenses incurred in connection with the Offer and Merger were paid by the Company using the Company's available cash on hand and Astellas provided the remaining funds required to consummate the Offer and the Merger to Merger Sub from its available cash on hand.

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 The foregoing description of certain provisions of the Merger Agreement is qualified in its entirety by reference to the Merger Agreement, a copy of which was filed as Exhibit 2.1 to the Form 8-K filed by the Company with the SEC on May 17, 2010.

ITEM 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Pursuant to the terms of the Merger Agreement, following the Acceptance Time, each of Colin Goddard, Santo J. Costa, Joseph Klein, III, Kenneth B. Lee, Jr., David W. Niemiec, Herbert M. Pinedo and John P. White resigned from the Board of Directors of the Company (the "Board"), effective June 3, 2010.  Pursuant to the Merger Agreement, and effective as of June 3, 2010, designees of Astellas, William Fitzsimmons, Linda Friedman, Stephen Knowles and Patrick Shea, were appointed to the Board.  Each of Astellas' designees are officers of Astellas or one of its subsidiaries.  Additional information about Astellas' designees was previously disclosed in the Information Statement comprising Annex C to Amendment No. 6 to the Company's Solicitation/Recommendation S tatement on Schedule 14D-9 filed with the SEC on May 20, 2010 and is incorporated herein by reference.  Effective on June 3, 2010, Robert A. Ingram also resigned from the Board.  In addition, pursuant to the employment agreement, as amended, between the Company and Dr. Colin Goddard, the Company's Chief Executive Officer, Dr. Goddard gave notice on June 3, 2010 of his election to terminate his employment for "good reason" based on the Company Change in Control, which shall become effective on July 2, 2010 unless otherwise agreed to by the relevant parties.

Pursuant to the terms of the Merger Agreement, at the Effective Time, the directors of the Company were removed and Linda Friedman, Seigo Kashii and Stephen Knowles, the directors of Merger Sub immediately prior to the Effective Time, became the initial directors of the surviving corporation.

ITEM 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

Pursuant to the terms of the Merger Agreement, at the Effective Time, the Company's Certificate of Incorporation was amended and restated in its entirety.  A copy of the Company's certificate of incorporation, as amended and restated pursuant to the Merger, is attached hereto as Exhibit 3.1 and incorporated herein by reference.

Pursuant to the terms of the Merger Agreement, at the Effective Time, the Company's bylaws were amended and restated in their entirety.  A copy of the Company's bylaws, as amended and restated pursuant to the Merger, is attached hereto as Exhibit 3.2 and incorporated herein by reference.

ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits.

See Exhibit Index.

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SIGNATURE

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.

Date:  June 9, 2010

OSI Pharmaceuticals, Inc.
By:	/s/ Barbara A. Wood
	Barbara A. Wood
	Senior Vice President, General Counsel and Secretary

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EXHIBIT INDEX

Exhibit No.	Description
3.1	Amended and Restated Certificate of Incorporation of OSI Pharmaceuticals, Inc.
3.2	Bylaws of the Surviving Corporation
99.1	Press Release of OSI Pharmaceuticals, dated June 4, 2010
99.2	Press Release of OSI Pharmaceuticals, dated June 9, 2010

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EX-3.1

Exhibit 3.1

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF OSI PHARMACEUTICALS, INC.

 ARTICLE I

The name of this corporation is OSI Pharmaceuticals, Inc. (the “Corporation”).

ARTICLE II

The registered agent and the address of the registered office in the State of Delaware are the Corporation Service Company, 2711 Centerville Road, Suite 400, City of Wilmington, County of New Castle, Delaware 19808.

ARTICLE III

The purpose of the Corporation is to engage in any lawful act or activity for which a corporation may be organized under the General Corporation Law of the State of Delaware.

ARTICLE IV

The total number of shares of stock which the Corporation is authorized to issue is 205,000,000 shares, consisting of 200,000,000 shares of Common Stock (“Common Stock”), having a par value of $0.01 per share, and 5,000,000 shares of Preferred Stock having a par value of $0.01 per share.

ARTICLE V

The Board of Directors is authorized to adopt, amend or repeal the Bylaws of the Corporation, except as otherwise provided therein.  Election of directors need not be by ballot.

ARTICLE VI

The Corporation reserves the right to adopt, repeal, rescind or amend in any respect any provisions contained in this Certificate of Incorporation in the manner now or hereafter prescribed by applicable law, and all rights conferred on stockholders herein are granted subject to this reservation.

ARTICLE VII

SECTION 1. RIGHT TO INDEMNIFICATION. Each person who was or is made a party or is threatened to be made a party to or is involved in any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative ("Proceeding"), by reason of the fact that he, or a person of whom he is the legal representative, is or was the director, officer, employee or agent of the Corporation or is or was serving at the request of the Corporation as a director, officer, employee or agent of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to employee benefit plans, whether the basis of such Proceeding is alleged action in an official capacity as a director, officer, employee or agent or in any other capacity while serving as a director , officer, employee or agent, shall be indemnified and held harmless by the Corporation to the fullest extent authorized by the Delaware General Corporation Law, as the same exists or may hereafter be amended (or, in the case of any such amendment, only to the extent that such amendment permits the Corporation to provide

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broader indemnification rights than said law permitted the Corporation to provide prior to such amendment), against all expenses, liability and loss (including attorneys' fees, judgments, fines, ERISA excise taxes or penalties and amounts paid or to be paid in settlement) reasonably incurred or suffered by such person in connection therewith; provided, however, that the Corporation shall indemnify any such person seeking indemnity in connection with a Proceeding (or part thereof) initiated by such person only if the proceeding (or part thereof) was authorized by the Board of Directors of the Corporation. The right to indemnification conferred in this Section 1 shall be a contract right and shall include the right to be paid by the Corporation expenses incurred in defending any such P roceeding in advance of its final disposition; provided, however, that if the Delaware General Corporation Law requires, the payment of such expenses incurred by a director or officer in his capacity as a director or officer (and not in any other capacity in which service was or is rendered by such person while a director or officer, including, without limitation, service to an employee benefit plan) in advance of the final disposition of such Proceeding, shall be made only upon delivery to the Corporation of an undertaking, by or on behalf of such director or officer, to repay all amounts so advanced if it should be determined ultimately that such director of officer is not entitled to be indemnified under this Section or otherwise.

SECTION 2. NON-EXCLUSIVITY OF RIGHTS. The rights conferred on any person by Section 1 shall not be exclusive of any other right which such person may have or hereafter acquire under any statute, provision of the Certificate of Incorporation, by-laws, agreement, vote of stockholders or disinterested directors, or otherwise.

SECTION 3. LIMITATION OF LIABILITY OF DIRECTORS. A director of the Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director except for liability (i) for any breach of the director's duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any transaction from which the director derived an improper personal benefit.

SECTION 4. INSURANCE. The Corporation may maintain insurance, at its expense, to protect itself and any such director, officer, employee or agent of the Corporation or another corporation, partnership, joint venture, trust or other enterprise against any such expense, liability or loss, whether or not the Corporation would have the power to indemnify such person against such expense, liability or loss under the Delaware General Corporation Law.

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EX-3.2

Exhibit 3.2

THIRD AMENDED AND RESTATED BYLAWS OF OSI PHARMACEUTICALS, INC.

ARTICLE 1

Offices

1.1           Principal Office.  The Board of Directors shall fix the location of the principal executive office of the Corporation at any place within or outside the State of Delaware.

1.2           Additional Offices.  The Board of Directors (the “Board”) may at any time establish branch or subordinate offices at any place or places.

ARTICLE 2

Meeting of Stockholders

2.1           Place of Meeting.  All meetings of the stockholders for the election of directors shall be held at the principal office of the Corporation, at such place as may be fixed from time to time by the Board or at such other place either within or without the State of Delaware as shall be designated from time to time by the Board and stated in the notice of the meeting.  Meetings of stockholders for any purpose may be held at such time and place within or without the State of Delaware as the Board may fix from time to time and as shall be stated in the notice of the meeting or in a duly executed waiver of notice thereof.

2.2           Annual Meeting.  Annual meetings of stockholders shall be held at such date and time as shall be designated from time to time by the Board and stated in the notice of the meeting.  At such annual meetings, the stockholders shall elect a Board and transact such other business as may properly be brought before the meetings.

2.3           Special Meetings.  Special meetings of the stockholders may be called for any purpose or purposes, unless otherwise prescribed by the statute or by the Certificate of Incorporation, at the request of the Board, the Chairman of the Board, the President or the holders of shares entitled to cast not less than ten percent (10%) of the votes at the meeting or such additional persons as may be provided in the Certificate of Incorporation or these Bylaws.  Such request shall state the purpose or purposes of the proposed meeting.  Upon request in writing that a special meeting of stockholders be called for any proper purpose, directed to the Chairman of the B oard, the President, a Vice President or the Secretary by any person (other than the Board) entitled to call a special meeting of stockholders, the person forthwith shall cause notice to be given to the stockholders entitled to vote that a meeting will be held at a time requested by the person or persons calling the meeting, such time not to be less than ten (10) nor more than sixty (60) days after receipt of the request.  Such request shall state the purpose or purposes of the proposed meeting.

2.4           Notice of Meetings.  Written notice of stockholders’ meetings, stating the place, date and time of the meeting and the purpose or purposes for which the meeting is called, shall be given to each stockholder entitled to vote at such meeting not less than ten (10) nor more than sixty (60) days prior to the meeting.

When a meeting is adjourned to another place, date or time, written notice need not be given of the adjourned meeting if the place, date and time thereof are announced at the meeting at which the adjournment is taken; provided, however, that if the date of any adjourned meeting is more than thirty (30) days after the date for which the meeting was originally noticed, or if a new record date is fixed for the adjourned meeting, written notice of the place, date and time of the adjourned meeting shall be given

in conformity herewith.  At any adjourned meeting, any business may be transacted which might have been transacted at the original meeting.

2.4.1           Without limiting the manner by which notice otherwise may be given effectively to stockholders, any notice to stockholders given by the corporation under any provision of Delaware General Corporation Law, the certificate of incorporation, or these bylaws shall be effective if given by a form of electronic transmission consented to by the stockholder to whom the notice is given.  Any such consent shall be revocable by the stockholder by written notice to the corporation.  Any such consent shall be deemed revoked if (i) the corporation is unable to deliver by electronic transmission two consecutive notices given by the corporation in accordance with such consent, and (ii) such inability becomes known to the secretary or an as sistant secretary of the corporation or to the transfer agent or other person responsible for the giving of notice; provided, however, the inadvertent failure to treat such inability as a revocation shall not invalidate any meeting or other action.  Notice given pursuant to this subparagraph (e) shall be deemed given:  (1) if by facsimile telecommunication, when directed to a number at which the stockholder has consented to receive notice; (2) if by electronic mail, when directed to an electronic mail address at which the stockholder has consented to receive notice; (3) if by a posting on an electronic network together with separate notice to the stockholder of such specific posting, upon the later of (A) such posting and (B) the giving of such separate notice; and (4) if by any other form of electronic transmission, when directed to the stockholder.  An affidavit of the secretary or an assistant secretary or of the transfer agent or other agent of the corporation that the notic e has been given by a form of electronic transmission shall, in the absence of fraud, be prima facie evidence of the facts stated therein.  For purposes of these bylaws, “electronic transmission” means any form of communication, not directly involving the physical transmission of paper, that creates a record that may be retained, retrieved and reviewed by a recipient thereof, and that may be directly reproduced in paper form by such a recipient through an automated process.

2.5           Business Matter of a Special Meeting.  Business transacted at any special meeting of stockholders shall be limited to the purposes stated in the notice.

2.6           List of Stockholders.  The officer in charge of the stock ledger of the Corporation or the transfer agent shall prepare and make, at least ten (10) days before every meeting of stockholders, a complete list of the stockholders entitled to vote at the meeting arranged in alphabetical order, and showing the address of each stockholder and the number of shares registered in the name of each stockholder.  Such list shall be open to the examination of any stockholder, for any purpose germane to the meeting, during ordinary business hours, for a period of at least ten (10) days prior to the meeting, at a place within the city where the meeting is to be held, which pl ace, if other than the place of the meeting, shall be specified in the notice of the meeting.  The list shall also be produced and kept at the place of the meeting during the whole time thereof, and may be inspected by any stockholder who is present in person thereat.

2.7           Organization and Conduct of Business.  The Chairman of the Board or, in his or her absence, the President of the Corporation or, in their absence, such person as the Board may have designated or, in the absence of such a person, such person as may be chosen by the holders of a majority of the shares entitled to vote who are present, in person or by proxy, shall call to order any meeting of the stockholders and act as Chairman of the meeting.  In the absence of the Secretary of the Corporation, the Secretary of the meeting shall be such person as the Chairman appoints.

The Chairman of any meeting of stockholders shall determine the order of business and the procedure at the meeting, including such regulation of the manner of voting and the conduct of discussion as seems to him or her in order.

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2.8           Quorum and Adjournments.  Except where otherwise provided by law or the Certificate of Incorporation or these Bylaws, the holders of a majority of the stock issued and outstanding and entitled to vote, present in person or represented in proxy, shall constitute a quorum at all meetings of the stockholders.  The stockholders present at a duly called or held meeting at which a quorum is present may continue to do business until adjournment, notwithstanding the withdrawal of enough stockholders to have less than a quorum if any action taken (other than adjournment) is approved by at least a majority of the shares required to constitute a quorum.  At such adjourned meeting at which a quorum is present or represented, any business may be transacted which might have been transacted at the meeting as originally notified.  If, however, a quorum shall not be present or represented at any meeting of the stockholders, the stockholders entitled to vote thereat who are present in person or represented by proxy shall have the power to adjourn the meeting from time to time, without notice other than announcement at the meeting, until a quorum shall be present or represented.

2.9           Voting Rights.  Unless otherwise provided in the Certificate of Incorporation, each stockholder shall at every meeting of the stockholders be entitled to one vote in person or by proxy for each share of the capital stock having voting power held by such stockholder.

2.10           Majority Vote.  When a quorum is present at any meeting, the vote of the holders of a majority of the stock having voting power present in person or represented by proxy shall decide any question brought before such meeting, unless the question is one upon which by express provision of the statutes or of the Certificate of Incorporation or of these Bylaws, a different vote is required in which case such express provision shall govern and control the decision of such question.

2.11           Record Date for Stockholder Notice and Voting.  For purposes of determining the stockholders entitled to notice of any meeting or to vote, or entitled to receive payment of any dividend or other distribution, or entitled to exercise any right in respect of any change, conversion or exchange of stock or for the purpose of any other lawful action, the Board may fix, in advance, a record date, which shall not be more than sixty (60) days nor less than ten (10) days before the date of any such meeting nor more than sixty (60) days before any other action.

If the Board does not so fix a record date, the record date for determining stockholders entitled to notice of or to vote at a meeting of stockholders shall be at the close of business on the business day next preceding the day on which notice is given or, if notice is waived, at the close of business on the business day next preceding the day on which the meeting is held.

2.12           Proxies.  Every person entitled to vote for directors or on any other matter shall have the right to do so either in person or by one or more agents authorized by a written proxy signed by the person and filed with the Secretary of the Corporation.  A proxy shall be deemed signed if the stockholder’s name is placed on the proxy (whether by manual signature, typewriting, telegraphic transmission or otherwise) by the stockholder or the stockholder’s attorney-in-fact.  A validly executed proxy which does not state that it is irrevocable shall continue in full force and effect unless (i) revoked by the person executing it, before the vote pur suant to that proxy, by a writing delivered to the Corporation stating that the proxy is revoked or by a subsequent proxy executed by, or attendance at the meeting and voting in person by, the person executing the proxy; or (ii) written notice of the death or incapacity of the maker of that proxy is received by the Corporation before the vote pursuant to that proxy is counted; provided, however, that no proxy shall be valid after the expiration of eleven months from the date of the proxy, unless otherwise provided in the proxy.

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2.13           Inspectors of Election.   Before any meeting of stockholders, the Board may appoint any person other than nominees for office to act as inspectors of election at the meeting or its adjournment.  If no inspectors of election are so appointed, the Chairman of the meeting may, and on the request of any stockholder or a stockholder’s proxy shall, appoint inspectors of election at the meeting.  The number of inspectors shall be either one (1) or three (3).  If inspectors are appointed at a meeting on the request of one or more stockholders or proxies, the holders of a majority of shares or their proxies present at the meeting shall de termine whether one (1) or three (3) inspectors are to be appointed.  If any person appointed as inspector fails to appear or fails or refuses to act, the Chairman of the meeting may, and upon the request of any stockholder or a stockholder’s proxy shall, appoint a person to fill that vacancy.

2.14           Action Without Meeting by Written Consent.  All actions required to be taken at any annual or special meeting may be taken without a meeting, without prior notice and without a vote, if a consent or consents in writing, setting forth the action so taken, shall be signed by the holders of outstanding stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares entitled to vote thereon were present and voted and shall be delivered to the Corporation by delivery to its registered office, its principal place of business, or an officer or agent of the Corporation having custody of the book in which proceedings of meetings or stockholders are recorded.

ARTICLE 3

Directors

3.1           Number; Qualifications.  The authorized number of the directors shall not be less than one (1) nor more than twenty-one (21).  The exact number may be fixed from time to time within such limit by a duly adopted resolution of the Board or stockholders.  All directors shall be elected at the annual meeting or any special meeting of the stockholders, except as provided in Section 3.2 hereof, and each director so elected shall hold office until the next annual meeting or any special meeting or until his or her successor is elected and qualified or until his or her earlier death, resignation, or removal.  Directors need not be stockholders.

3.2           Resignation and Vacancies.  A vacancy or vacancies in the Board shall be deemed to exist in the case of the death, resignation or removal of any director, or if the authorized number of directors be increased.  Vacancies may be filled by a majority of the remaining directors, though less than a quorum, or by a sole remaining director, unless otherwise provided in the Certificate of Incorporation.  The stockholders may elect a director or directors at any time to fill any vacancy or vacancies not filled by the directors.

Any director may resign at any time by giving written notice to the Board.  Any resignation shall take effect at the date of the receipt of that notice or at any later time specified in that notice; and, unless otherwise specified in that notice, the acceptance of the resignation shall not be necessary to make it effective.  Any resignation is without prejudice to the rights, if any, of the Corporation under any contract to which the director is a party.  If resignation of a director is tendered to take effect at a future time, the Board shall have power to elect a successor to take office when the resignation is to become effective.  If there are no directors in office, then an election of directors may be held in the manner provided by statute.

3.3           Removal of Directors.  Unless otherwise restricted by statute, the Certificate of Incorporation or these Bylaws, any director or the entire Board may be removed, with or without cause, by the holders of at least a majority of the shares entitled to vote at an election of directors.

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3.4           Powers.  The business of the Corporation shall be managed by or under the direction of the Board which may exercise all such powers of the Corporation and do all such lawful acts and things which are not by statute or by the Certificate of Incorporation or by these Bylaws directed or required to be exercised or done by the stockholders, or prohibited to the Board.

Without prejudice to these general powers, and subject to the same limitations, the directors shall have the power to:

(a)           Select and remove all officers, agents, and employees of the Corporation; prescribe any powers and duties for them that are consistent with law, with the Certificate of Incorporation, and with these Bylaws; fix their compensation; and require from them security for faithful service;

(b)           Confer upon any office the power to appoint, remove and suspend subordinate officers, employees and agents;

(c)           Change the principal executive office or the principal business office in the State of Delaware or any other state from one location to another, cause the Corporation to be qualified to do business in any other state, territory, dependency or country and conduct business within or without the State of Delaware; and designate any place within or without the State of Delaware for the holding of any stockholders meeting, or meetings, including annual meetings;

(d)           Adopt, make, and use a corporate seal; prescribe the forms of certificates of stock; and alter the form of the seal and certificates;

(e)           Authorize the issuance of shares of stock of the Corporation on any lawful terms, in consideration of money paid, labor done, services actually rendered, debts or securities canceled, tangible or intangible property actually received;

(f)           Borrow money and incur indebtedness on behalf of the Corporation, and cause to be executed and delivered for the Corporation’s purposes, in the corporate name, promissory notes, bonds, debentures, deeds of trust mortgages, pledges, hypothecation and other evidences of debt and securities;

(g)           Declare dividends from time to time in accordance with law,

(h)           Adopt from time to time such stock option, stock purchase, bonus or other compensation plans for directors, officers, employees and agents of the Corporation and its subsidiaries as it may determine; and

(i)           Adopt from time to time regulations not inconsistent with these Bylaws for the management of the Corporation’s business and affairs.

3.5           Place of Meetings.  The Board may hold meetings, both regular and special, either within or without the State of Delaware.

3.6           Annual Meetings.  The annual meetings of the Board shall be held immediately following the annual meeting of stockholders, and no notice of such meeting shall be necessary to the Board, provided a quorum shall be present.  The annual meetings shall be for the purposes of organization, and an election of officers and the transaction of other business.

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3.7           Regular Meetings.  Regular meetings of the Board may be held without notice at such time and place as may be determined from time to time by the Board.

3.8           Special Meetings.  Special meetings of the Board may be called by the Chairman of the Board, the President, a Vice President, the Secretary or a majority of the Board upon one (1) day’s notice to each director.

3.9           Quorum and Adjournments.  At all meetings of the Board, a majority of the directors then in office shall constitute a quorum for the transaction of business, and the act of a majority of the directors present at any meeting at which there is a quorum shall be the act of the Board, except as may otherwise be specifically provided by law or the Certificate of Incorporation.  If a quorum is not present at any meeting of the Board, the directors present may adjourn the meeting from time to time, without notice other than announcement at the meeting at which the adjournment is taken, until a quorum shall be present.  A meeting at which a quorum is initiall y present may continue to transact business notwithstanding the withdrawal of directors, if any action taken is approved of by at least a majority of the required quorum for that meeting.

3.10           Action Without Meeting.  Unless otherwise restricted by the Certificate of Incorporation or these Bylaws, any action required or permitted to be taken at any meeting of the Board or of any committee thereof may be taken without a meeting, if all members of the Board or committee, as the case may be, consent thereto in writing or by electronic transmission, and such writing or writings or electronic transmission or transmissions are filed with the minutes of proceedings of the Board or committee.  Such filing shall be in paper form if the minutes are maintained in paper form and shall be in electronic form if the minutes are maintained in electronic form.

3.11           Telephone Meetings.  Unless otherwise restricted by the Certificate of Incorporation or these Bylaws, any member of the Board or any committee may participate in a meeting by means of conference telephone or similar communications equipment by means of which all persons participating in the meeting can hear each other, and such participation in a meeting shall constitute presence in person at the meeting.

3.12           Waiver of Notice.  Notice of a meeting need not be given to any director who signs a waiver of notice or a consent to holding the meeting or an approval of the minutes thereof, whether before or after the meeting, or who attends the meeting without protesting, prior thereto or at its commencement, the lack of notice to such director.  All such waivers, consents and approvals shall be filed with the corporate records or made a part of the minutes of the meeting.

3.13           Fees and Compensation of Directors.  Directors and members of committees may receive such compensation, if any, for their services, and such reimbursement for expenses, as may be fixed or determined by resolution of the Board of Directors.  No such payment shall preclude any director from serving the Corporation in any other capacity and receiving compensation therefor.  Members of special or standing committees may be allowed like compensation for attending committee meetings.

3.14           Rights of Inspection.  Every director shall have the absolute right at any reasonable time to inspect and copy all books, records and documents of every kind and to inspect the physical properties of the Corporation and also of its subsidiary corporations, domestic or foreign.  Such inspection by a director may be made in person or by agent or attorney and includes the right to copy and obtain extracts.

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ARTICLE 4

Committees of Directors

4.1           Executive Committee.  The Board of Directors may, by resolution passed by a majority of the whole Board, appoint an Executive Committee of not less than one member, each of whom shall be a director.  The Executive Committee to the extent permitted by law shall have and may exercise, when the Board of Directors is not in session, all powers of the Board in the management of the business and affairs of the corporation, including, without limitation, the power and authority to declare a dividend or to authorize the issuance of stock, except such committee shall not have the power or authority to amend the Certificate of Incorporation, to adopt an agreement or merg er or consolidation, to recommend to the stockholders the sale, lease or exchange of all of substantially all of the corporation’s property and assets, to recommend to the stockholders of the corporation a dissolution of the corporation or a revocation of a dissolution, or to amend these Bylaws.

4.2           Other Committees.  The Board may, by resolution passed by a majority of the entire Board, from time to time appoint such other committees as may be permitted by law.  Such other committees appointed by the Board of Directors shall have such powers and perform such duties as may be prescribed by the resolution or resolutions creating such committee, but in no event shall any such committee have the powers denied to the Executive Committee in these Bylaws.  Such committee or committees shall have such name or names as may be determined from time to time by resolution adopted by the Board.

4.3           Term.  The members of all committees of the Board of Directors shall serve a term coexistent with that of the Board of Directors which shall have appointed such committee.  The Board, subject to the provisions of subsections 4.1 and 4.2 of this Article 4, may at any time increase or decrease the number of members of a committee or terminate the existence of a committee; provided that no committee shall consist of less than one member.  The membership of a committee member shall terminate on the date of his death or voluntary resignation, but the Board may at any time for any reason remove any individual committee member and the Board may fill any committee vacancy created by death, resignation, removal or increase in the number of members of the committee.  The Board of Directors may designate one or more directors as alternate members of any committee, who may replace any absent or disqualified member at any meeting of the committee, and, in addition, in the absence or disqualification of any member of a committee, the member or members thereof present at any meeting and not disqualified from voting, whether or not he or they constitute a quorum, may unanimously appoint another member of the Board of Directors to act at the meeting in the place of any such absent or disqualified member.

4.4           Meetings.  Unless the Board of Directors shall otherwise provide, regular meetings of the Executive Committee or any other committee appointed pursuant to this Article 4 shall be held at such times and places as are determined by the Board of Directors, or by any such committee, and when notice thereof has been given to each member of such committee, no further notice of such regular meetings need be given thereafter; special meetings of any such committee may be held at any place which has been designated from time to time by resolution of such committee or by written consent of all memb ers thereof, and may be called by any director who is a member of such committee upon written notice to the members of such committee of the time and place of such special meeting given in the manner provided for the giving of written notice to members of the Board of Directors of the time and place of special meetings of the Board of Directors.  Notice of any special meeting of any committee may be waived in writing at

7

any time after the meeting and will be waived by any director by attendance thereat.  A majority of the authorized number of members of any such committee shall constitute a quorum for the transaction of business, and the act of a majority of those present at any meeting at which a quorum is present shall be the act of such committee.  Each committee shall keep regular minutes of its meetings and report the same to the Board when required.

ARTICLE 5

Officers

5.1           Officers Designated.  The officers of the Corporation shall be chosen by the Board and shall be a President, a Secretary and a Treasurer.  The Board may also choose a Chairman of the Board, a Deputy President, one or more Vice Presidents, and one or more assistant Secretaries and assistant Treasurers.  Any number of offices may be held by the same person, unless the Certificate of Incorporation or these Bylaws otherwise provide.

5.2           Appointment of Officers.  The officers of the Corporation, except such officers as may be appointed in accordance with the provisions of Section 5.3 or 5.5 hereof, shall be appointed by the Board, and each shall serve at the pleasure of the Board, subject to the rights, if any, of an officer under any contract of employment.

5.3           Subordinate Officers.  The Board may appoint, and may empower the president to appoint, such other officers and agents as the business of the Corporation may require, each of whom shall hold office for such period, have such authority and perform such duties as are provided in the Bylaws or as the Board may from time to time determine.

5.4           Removal and Resignation of Officers.  Subject to the rights, if any, of an officer under any contract of employment, any officer may be removed, either with or without cause, by an affirmative vote of the majority of the Board, at any regular or special meeting of the Board, or, except in case of an officer chosen by the Board, by any officer upon whom such power of removal may be conferred by the Board.

Any officer may resign at any time by giving written notice to the Corporation.  Any resignation shall take effect at the date of the receipt of that notice or at any later time specified in that notice; and, unless otherwise specified in that notice, the acceptance of the resignation shall not be necessary to make it effective.  Any resignation is without prejudice to the rights, if any, of the Corporation under any contract to which the officer is a party.

5.5           Vacancies in Offices.  A vacancy in any office because of death, resignation, removal, disqualification or any other cause shall be filled in the manner prescribed in these Bylaws for regular appointment to that office.

5.6           Compensation.  The salaries of all officers of the Corporation shall be fixed from time to time by the Board and no officer shall be prevented from receiving a salary because he or she is also a director of the Corporation.

5.7           The Chairman of the Board.  The Chairman of the Board, if such an officer be elected, shall, if present, perform such other powers and duties as may be assigned to him from time to time by the Board.  If there is no President, the Chairman of the Board shall also be the Chief Executive Officer of the Corporation and shall have the powers and duties prescribed in Section 5.8 hereof.

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5.8           The President.  Subject to such supervisory powers, if any, as may be given by the Board to the Chairman of the Board, if there be such an officer, the President shall be the Chief Executive Officer of the Corporation, shall preside at all meetings of the stockholders and in the absence of the Chairman of the Board, or if there be none, at all meetings of the Board, shall have general and active management of the business of the Corporation and shall see that all orders and resolutions of the Board are carried into effect.  He or she shall execute bonds, mortgages and other contracts requiring a seal, under the seal of the Corporation, except where required or permitted by law to be otherwise signed and executed and except where the signing and execution thereof shall be expressly delegated by the Board to some other officer or agent of the Corporation.

5.9           The Vice President.  The Vice President (or in the event there be more than one, the Vice Presidents in the order designated by the directors, or in the absence of any designation, in the order of their election), shall, in the absence of the President or in the event of his or her disability or refusal to act, perform the duties of the President, and when so acting, shall have the powers of and be subject to all the restrictions upon the President.  The Vice President(s) shall perform such other duties and have such other powers as may from time to time be prescribed for them by the Board, the President, the Chairman of the Board or these Bylaws.

5.10           The Secretary.  The Secretary shall attend all meetings of the Board and the stockholders and record all votes and the proceedings of the meetings in a book to be kept for that purpose and shall perform like duties for the standing committees, when required.  The Secretary shall give, or cause to be given, notice of all meetings of stockholders and special meetings of the Board, and shall perform such other duties as may from time to time be prescribed by the Board, the Chairman of the Board or the President, under whose supervision he or she shall act.  The Secretary shall have custody of the seal of the Corporation, and the Secretary, or an Assista nt Secretary, shall have authority to affix the same to any instrument requiring it, and, when so affixed, the seal may be attested by his or her signature or by the signature of such Assistant Secretary.  The Board may give general authority to any other officer to affix the seal of the Corporation and to attest the affixing thereof by his or her signature.  The Secretary shall keep, or cause to be kept, at the principal executive office or at the office of the Corporation’s transfer agent or registrar, as determined by resolution of the Board, a share register, or a duplicate share register, showing the names of all stockholders and their addresses, the number and classes of shares held by each, the number and date of certificates issued for the same and the number and date of cancellation of every certificate surrendered for cancellation.

5.11           The Treasurer.  The Treasurer shall have the custody of the Corporate funds and securities and shall keep full and accurate accounts of receipts and disbursements in books belonging to the Corporation and shall deposit all moneys and other valuable effects in the name and to the credit of the Corporation in such depositories as may be designated by the Board.  The Treasurer shall disburse the funds of the Corporation as may be ordered by the Board, taking proper vouchers for such disbursements, and shall render to the President and the Board, at its regular meetings, or when the Board so requires, an account of all his or her transactions as Treasurer and of t he financial condition of the Corporation.

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ARTICLE 6

[Intentionally omitted]

ARTICLE 7

Stock Certificates

7.1           Certificates for Shares.  The shares of the Corporation shall be represented by certificates or shall be uncertificated.  Certificates shall be signed by, or in the name of the Corporation by, the Chairman of the Board, or the President or the Deputy President or a Vice President and by the Treasurer or an Assistant Treasurer, or the Secretary or an Assistant Secretary of the Corporation.

Within a reasonable time after the issuance or transfer of uncertified stock, the Corporation shall send to the registered owner thereof a written notice containing the information required by the DGCL or a statement that the Corporation will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights.

7.2           Signatures on Certificates.  Any or all of the signatures on a certificate may be a facsimile.  In case any officer, transfer agent or registrar who has signed or whose facsimile signature has been placed upon a certificate shall have ceased to be such officer, transfer agent or registrar before such certificate is issued, it may be issued by the Corporation with the same effect as if he or she were such officer, transfer agent or registrar at the date of issue.

7.3           Transfer of Stock.  Upon surrender to the Corporation or the transfer agent of the Corporation of a certificate of shares duly endorsed or accompanied by proper evidence of succession, assignation or authority to transfer, it shall be the duty of the Corporation to issue a new certificate to the person entitled thereto, cancel the old certificate and record the transaction upon its books.  Upon receipt of proper transfer instructions from the registered owner of uncertificated share, such uncertificated shares shall be canceled and issuance of new equivalent uncertificated shares or certificated shares shall be made to the person entitled thereto and the transa ction shall be recorded upon the books of the Corporation.

7.4           Registered Stockholders.  The Corporation shall be entitled to recognize the exclusive right of a person registered on its books as the owner of shares to receive dividends,  and to vote as such owner, and to hold liable for calls and assessments a percent registered on its books as the owner of shares, and shall not be bound to recognize any equitable or other claim to or interest in such share or shares on the part of any other person, whether or not it shall have express or other notice thereof, except as otherwise provided by the laws of Delaware.

7.5           Record Date.  In order that the Corporation may determine the stockholders of record who are entitled to receive notice of, or to vote at, any meeting of stockholders or any adjournment thereof or to express consent to corporate action in writing without a meeting, or entitled to receive payment of any dividend or other distribution or allotment of any rights, or to exercise any rights in respect of any change, conversion, or exchange of stock or for the purpose of any lawful action, the Board may fix, in advance, a record date which shall not be more than sixty (60) nor less than ten (10) days prior to the date of such meeting, nor more than sixty (60) days prior to the date of any other action.  A determination of stockholders of record entitled to

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notice or to vote at a meeting of stockholders shall apply to any adjournment of the meeting; provided, however, that the Board may fix a new record date for the adjourned meeting.

7.6           Lost, Stolen or Destroyed Certificates.  The Board may direct that a new certificate or certificates be issued to replace any certificate or certificates theretofore issued by the Corporation alleged to have been lost, stolen or destroyed, upon the making of an affidavit of that fact by the person claiming the certificate of stock to be lost, stolen or destroyed.  When authorizing the issue of a new certificate or certificates, the Board may, in its discretion and as a condition precedent to the issuance thereof require the owner of the lost, stolen or destroyed certificate or certificates, or his or her legal representative, to advertise the same in such manne r as it shall require, and/or to give the Corporation a bond in such sum as it may direct as indemnity against any claim that may be made against the Corporation with respect to the certificate alleged to have been lost, stolen or destroyed.

ARTICLE 8

Notices

8.1           Notice.  Whenever, under the provisions of the statutes or of the Certificate of Incorporation or of these Bylaws, notice is required to be given to any director or stockholder it shall not be construed to mean personal notice, but such notice may be given in writing, by mail, addressed to such director or stockholder, at his or her address as it appears on the records of the Corporation, with postage thereon prepaid, and such notice shall be deemed to be given at the time when the same shall be deposited in the United States mail.  Notice to directors may also be given by telegram or telephone.

8.2           Waiver.  Whenever any notice is required to be given under the provisions of the statutes or of the Certificate of Incorporation or of these Bylaws, a waiver thereof in writing, signed by the person or persons entitled to said notice, whether before or after the time stated therein, shall be deemed equivalent thereto.

ARTICLE 9

General Provisions

9.1           Dividends.  Dividends upon the capital stock of the Corporation, subject to any restrictions contained in the DGCL or the provisions of the Certificate of Incorporation, if any, may be declared by the Board at any regular or special meeting.  Dividends may be paid in cash, in property or in shares of the capital stock, subject to the provisions of the Certificate of Incorporation.

9.2           Dividend Reserve.  Before payment of any dividend, there may be set aside out of any funds of the Corporation available for dividends such sum or sums as the directors from time to time, in their absolute discretion, think proper as a reserve or reserves to meet contingencies, or for equalizing dividends, or for repairing or maintaining any property of the Corporation, or for such other purpose as the directors shall think conducive to the interest of the Corporation, and the directors may modify or abolish any such reserve in the manner in which it was created.

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9.3           Annual Statement.  The Board shall present at each annual meeting, and at any special meeting of the stockholders when called for by vote of the stockholders, a full and clear statement of the business and condition of the Corporation.

9.4           Checks.  All checks or demands for money and notes of the Corporation shall be signed by such officer or officers or such other person or persons as the Board may from time to time designate.

9.5           Corporate Seal.  The Board may provide a suitable seal, containing the name of the Corporation, which seal shall be in charge of the Secretary.  If and when so directed by the Board or a committee thereof, duplicates of the seal may be kept and used by the Treasurer or by an Assistant Secretary or Assistant Treasurer.

9.6           Execution of Corporate Contracts and Instruments.  The Board, except as otherwise provided in these Bylaws, may authorize any officer or officers, or agent or agents, to enter into any contract or execute any instrument in the name of and on behalf of the Corporation; such authority may be general or confined to specific instances.  Unless so authorized or ratified by the Board or within the agency power of an officer, no officer, agent or employee shall have any power or authority to bind the Corporation by any contract or engagement or to pledge its credit or to render it liable for any purpose or for any amount.

ARTICLE 10

Amendments

In addition to the right of the stockholders of the Corporation to make, alter, amend, change, add to or repeal the Bylaws of the Corporation, the Board shall have the power (without the assent or vote of the stockholders) to make, alter, amend, change, add to or repeal the Bylaws of the Corporation.

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ARTICLE 1 OFFICES		1
1.1	Principal Office	1
1.2	Additional Offices	1
ARTICLE 2 MEETING OF STOCKHOLDERS		1
2.1	Place of Meeting	1
2.2	Annual Meeting	1
2.3	Special Meetings..	1
2.4	Notice of Meetings	1
2.5	Business Matter of a Special Meeting..	2
2.6	List of Stockholders	2
2.7	Organization and Conduct of Business.	2
2.8	Quorum and Adjournments.	3
2.9	Voting Rights.	3
2.10	Majority Vote..	3
2.11	Record Date for Stockholder Notice and Voting.	3
2.12	Proxies.	3
2.13	Inspectors of Election.	4
2.14	Action Without Meeting by Written Consent.	4
ARTICLE 3 DIRECTORS		4
3.1	Number; Qualifications.	4
3.2	Resignation and Vacancies	4
3.3	Removal of Directors	4
3.4	Powers	5
3.5	Place of Meetings	5
3.6	Annual Meetings	5
3.7	Regular Meetings	6
3.8	Special Meetings	6
3.9	Quorum and Adjournments.	6
3.10	Action Without Meeting	6
3.11	Telephone Meetings	6
3.12	Waiver of Notice	6
3.13	Fees and Compensation of Directors	6
3.14	Rights of Inspection	6

ARTICLE 4 COMMITTEES OF DIRECTORS		7
4.1	Executive Committee	7
4.2	Other Committees	7
4.3	Term	7
4.4	Meetings	7
ARTICLE 5 OFFICERS		8
5.1	Officers Designated.	8
5.2	Appointment of Officers	8
5.3	Subordinate Officers	8
5.4	Removal and Resignation of Officers	8
5.5	Vacancies in Offices	8
5.6	Compensation.	8
5.7	The Chairman of the Board	8
5.8	The President.	9
5.9	The Vice President.	9
5.10	The Secretary	9
5.11	The Treasurer	9
ARTICLE 6 [INTENTIONALLY OMITTED]		10
ARTICLE 7 STOCK CERTIFICATES		10
7.1	Certificates for Shares.	10
7.2	Signatures on Certificates.	10
7.3	Transfer of Stock	10
7.4	Registered Stockholders.	10
7.5	Record Date..	10
7.6	Lost, Stolen or Destroyed Certificates.	11
ARTICLE 8 NOTICES		11
8.1	Notice.	11
8.2	Waiver..	11
ARTICLE 9 GENERAL PROVISIONS		11
9.1	Dividends	11
9.2	Dividend Reserve	11
9.3	Annual Statement	12
9.4	Checks	12

9.5	Corporate Seal.	12
9.6	Execution of Corporate Contracts and Instruments..	12
ARTICLE 10 AMENDMENTS		12

EX-99.1

Exhibit 99.1

NEWS RELEASE

Contacts: OSI Pharmaceuticals, Inc. Kathy Galante (investors/media) Senior Director 631-962-2043 Kim Wittig (media) Director 631-962-2135	Media: Joele Frank, Wilkinson Brimmer Katcher Joele Frank/Andy Brimmer/Eric Brielmann 212-355-4449
	Investors: Burns McClellan Lisa Burns 212-213-0006

OSI Pharmaceuticals Announces Occurrence of a Fundamental Change for Convertible Notes

MELVILLE, NY – June 4, 2010 – OSI Pharmaceuticals, Inc. (Nasdaq: OSIP; the “Company”) announced today that its 2% Convertible Senior Subordinated Notes due 2025 (the “notes”) are convertible at the option of the holders and will remain convertible at least through July 6, 2010, as provided for in the Indenture (the “Indenture”) governing the notes.

The notes became convertible on June 3, 2010, when pursuant to a tender offer and acceptance of tendered shares, Astellas Pharma, Inc. became the beneficial owner, directly or indirectly, of fifty percent (50%) or more of the Company’s voting stock, which constitutes a Fundamental Change under the Indenture. During the thirty (30) day period after the announcement of the Fundamental Change, holders of the notes may convert the notes as a result of such Fundamental Change.  The conversion period relating to such Fundamental Change will continue through and including July 6, 2010.

The Company has elected, pursuant to the Indenture, to satisfy its conversion obligation in cash.  The notes are convertible at the conversion rate of 33.9847 shares of common stock of the Company per $1,000 principal amount of each note.

As previously announced, the notes also became convertible on April 1, 2010 and remain convertible through June 30, 2010 as a result of the satisfaction of the market price condition under the Indenture.  Depending on market conditions and other factors, the notes may remain

convertible in the third quarter of 2010 if the market price condition with respect to the third quarter of 2010 is also satisfied.

To exercise their conversion right as a result of the Fundamental Change described above, holders must surrender the notes for conversion to the conversion agent at any time on or before July 6, 2010 and follow the applicable depository procedures or, in the case of notes in the certificated form, surrender the notes to the conversion agent with appropriate signatures, endorsements and transfer documents as described in the Indenture and in the Fundamental Change Company Notice and Notice of Conversion Privilege distributed to the holders of the notes and published on the Company’s web site.

About OSI Pharmaceuticals

OSI Pharmaceuticals 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.

This news release contains forward-looking statements. These statements are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made.  Factors that might cause such a difference include, among others, OSI's and its collaborators' abilities to effectively market and sell Tarceva and to expand the approved indications for Tarceva, OSI’s ability to protect its intellectual property rights, safety concerns regarding Tarceva,  competition to Tarceva and OSI’s drug candidates  from other biotechnology and  pharmaceutical companies, the completion of clinical trials, the effects of FDA and other governmental regulation, including pricing controls,  OSI's ability to successfully develop and commercialize drug candidates, and other factors described in OSI Pharmaceuticals' filings with the Securities and Exchange Commission.

EX-99.2

Exhibit 99.2

NEWS RELEASE

Contacts: OSI Pharmaceuticals, Inc. Kathy Galante (investors/media) Senior Director 631-962-2043 Kim Wittig (media) Director 631-962-2135	Media: Joele Frank, Wilkinson Brimmer Katcher Joele Frank/Andy Brimmer/Eric Brielmann 212-355-4449
	Investors: Burns McClellan Lisa Burns 212-213-0006

OSI Pharmaceuticals Announces Occurrence of a Fundamental Change for Convertible Notes

MELVILLE, NY – June 9, 2010 – OSI Pharmaceuticals, Inc. (Nasdaq: OSIP; the “Company”) announced today that its 2% Convertible Senior Subordinated Notes due 2025 (the “notes”) are convertible at the option of the holders and will remain convertible at least through July 8, 2010, as provided for in the Indenture (the “Indenture”) governing the notes.

The notes became convertible on June 8, 2010, when pursuant to the Agreement and Plan of Merger dated May 16, 2010 by and among Astellas Pharma, Inc., certain of its affiliates and the Company, the Company merged with an indirect subsidiary of Astellas Pharma, Inc. (the “Merger”).  The Merger constitutes a Fundamental Change under the Indenture. During the thirty (30) day period after the announcement of the Fundamental Change, holders of the notes may convert the notes as a result of such Fundamental Change.  The conversion period relating to the Merger will continue through and including July 8, 2010.

The Company has elected, pursuant to the Indenture, to satisfy its conversion obligation in cash.  The notes are convertible at the conversion rate of 34.0420 shares of common stock of the Company per $1,000 principal amount of each note.

As previously announced, the notes also became convertible on June 3, 2010 when, pursuant to a tender offer and acceptance of tendered shares, Astellas Pharma, Inc. became the beneficial owner, directly or indirectly, of fifty percent (50%) or more of the Company’s voting stock.  The notes may remain convertible in connection with this event through July 6, 2010.

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In addition, as previously announced, the notes also became convertible on April 1, 2010 and remain convertible through June 30, 2010 as a result of the satisfaction of the market price condition under the Indenture.  Depending on market conditions and other factors, the notes may remain convertible in the third quarter of 2010 if the market price condition with respect to the third quarter of 2010 is also satisfied.

To exercise their conversion right as a result of the Merger, holders must surrender the notes for conversion to the conversion agent at any time on or before July 8, 2010 and follow the applicable depository procedures or, in the case of notes in the certificated form, surrender the notes to the conversion agent with appropriate signatures, endorsements and transfer documents as described in the Indenture and in the Fundamental Change Company Notice and Notice of Conversion Privilege distributed to the holders of the notes and published on the Company’s web site.

About OSI Pharmaceuticals

OSI Pharmaceuticals 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.

This news release contains forward-looking statements. These statements are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made.  Factors that might cause such a difference include, among others, OSI's and its collaborators' abilities to effectively market and sell Tarceva and to expand the approved indications for Tarceva, OSI’s ability to protect its intellectual property rights, safety concerns regarding Tarceva,  competition to Tarceva and OSI’s drug candidates  from other biotechnology and  pharmaceutical companies, the completion of clinical trials, the effects of FDA and other governmental regulation, including pricing controls,  OSI's ability to successfully develop and commercialize drug candidates, and other factors described in OSI Pharmaceuticals' filings with the Securities and Exchange Commission.

2