Exhibit 2 U.S. BIOSCIENCE One Tower Bridge 100 Front Street West Conshohocken, Pennsylvania 19428 (215) 832-0570 June 7, 1995 To Our Stockholders: On May 19, 1995, your Board of Directors adopted a Shareholder Rights Plan. As part of that Plan, the Board declared a dividend distribution of one Preferred Stock Purchase Right on each outstanding share of Common Stock of U.S. Bioscience, Inc. (the "Company"). A Summary of Rights explaining the terms of the Rights is enclosed herewith. The action taken increases your Board's ability to represent the interests of stockholders of the Company effectively in the event of an unsolicited takeover attempt. The Board considers these Rights to be an appropriate means of protecting both your right to retain your equity investment in the Company and the full value of that investment. Many other companies have issued rights similar to those approved by the Board. The distribution of these Rights is not intended to prevent a takeover of the Company on terms beneficial to its stockholders and, in fact, will not do so. It may, however, deter an attempt to acquire the Company in a manner or on terms that the Board determines not to be in the best interests of its stockholders. The Rights are designed to deal with the very serious problem of a takeover attempt that deprives the Company's Board and its stockholders of any real opportunity to determine the destiny of the Company. The Rights may be redeemed by the Company at $.001 per Right prior to the close of business on the tenth day after a public announcement that beneficial ownership of 15% or more of the Company's voting stock has been accumulated by a single acquiror or group (with certain exceptions), under the circumstances set forth in the Rights Agreement. The Board (under certain circumstances) may also, in its discretion, extend the period for redemption in accordance with the Rights NYFS02...:\09\78509\0002\1196\LTR4055D.12C June 7, 1995 Page 2 Agreement. Thus, the Rights should not interfere with a negotiated merger or other business combination approved by the Board. Issuance of the Rights does not in any way weaken the financial strength of the Company or interfere with its business plans. The issuance of the Rights has no present dilutive effect, will not affect reported earnings per share, is not taxable to the Company or to you under current federal income tax law, and will not change the way in which the Company's shares of Common Stock may be traded. If the Rights should become exercisable, stockholders, depending on then existing circumstances, may recognize taxable income. The Board was aware when it acted that some people have advanced arguments that securities of the sort we are issuing deter legitimate acquisition proposals. The Board carefully considered those views and concluded that the arguments are speculative and unconvincing and certainly do not justify leaving stockholders with less effective protection against unfair treatment by an acquiror who, after all, would be seeking its own advantage, not yours. The Board believes that these Rights represent a sound, reasonable and appropriate means of addressing the complex issues of corporate policy developed as a response to the threat of coercive takeovers. In declaring the Rights dividend, we have expressed ou confidence in U.S. Bioscience's future and we believe we have increased your ability to participate in that future. Sincerely, Phillip S. Schein, M.D. Chairman and Chief Executive Officer UNDER CERTAIN CIRCUMSTANCES AS PROVIDED IN THE RIGHTS AGREEMENT (AS REFERRED TO BELOW), RIGHTS ISSUED TO OR BENEFICIALLY OWNED BY ACQUIRING PERSONS OR THEIR AFFILIATES OR ASSOCIATES (AS SUCH TERMS ARE DEFINED IN THE RIGHTS AGREEMENT) OR ANY SUBSEQUENT HOLDER OF SUCH RIGHTS SHALL BE NULL AND VOID AND MAY NOT BE TRANSFERRED TO ANY PERSON. U.S. BIOSCIENCE, INC. SUMMARY OF RIGHTS TO PURCHASE SERIES A JUNIOR PREFERRED STOCK On May 19, 1995, the Board of Directors of U.S. Bioscience, Inc. (the "Company") declared a dividend distribution of one Preferred Stock Purchase Right for each outstanding share of Common Stock, par value $.005 per share (the "Common Stock"), of the Company. The distribution is payable as of May 29, 1995 to stockholders of record on that date. Each Right entitles the registered holder to purchase from the Company one one-hundredth (1/100) of a share of preferred stock of the Company, designated as Series A Junior Preferred Stock (the "Preferred Stock") at a price of $15 per one one-hundredth (1/100) of a share ("Exercise Price"). The description and terms of the Rights are set forth in a Rights Agreement, dated as of May 19, 1995, as hereafter amended from time to time (the "Rights Agreement"), between the Company and Chemical Mellon Shareholder Services L.L.C., as Rights Agent (the "Rights Agent"). As discussed below, initially the Rights will not be ---------------------------------------------------- exercisable, certificates will not be sent to stockholders and the ------------------------------------------------------------------ Rights will automatically trade with the Common Stock. ------------------------------------------------------ The Rights, unless earlier redeemed by the Board of Directors, become exercisable upon the close of business on the day (the "Distribution Date") which is the earlier of (i) the tenth day following a public announcement that a person or group of affiliated or associated persons, with certain exceptions set forth below, has acquired beneficial ownership of 15% or more of the outstanding voting stock of the Company (an "Acquiring Person") and (ii) the tenth business day (or such later date as may be determined by the Board of Directors prior to such time as any person or group of affiliated or associated persons becomes an Acquiring Person) after the date of the commencement or announcement of a person's or group's intention to commence a tender or exchange offer the consummation of which would result in the ownership of 30% or more of the Company's outstanding voting stock (even if no shares are actually purchased pursuant to such offer); prior thereto, the Rights would not be NYFS02...:\09\78509\0002\1196\EXH4055C.34B exercisable, would not be represented by a separate certificate, and would not be transferable apart from the Company's Common Stock, but will instead be evidenced, with respect to any of the Common Stock certificates outstanding as of May 29, 1995, by such Common Stock certificate with a copy of this Summary of Rights attached thereto. An Acquiring Person does not include (A) the Company, (B) any subsidiary of the Company, (C) any employee benefit plan or employee stock plan of the Company or of any subsidiary of the Company, or any trust or other entity organized, appointed, established or holding Common Stock for or pursuant to the terms of any such plan or (D) any person or group whose ownership of 15% or more of the shares of voting stock of the Company then outstanding results solely from (i) any action or transaction or transactions approved by the Board of Directors before such person or group became an Acquiring Person or (ii) a reduction in the number of issued and outstanding shares of voting stock of the Company pursuant to a transaction or transactions approved by the Board of Directors (provided that any person or group that does not become an Acquiring Person by reason of clause (i) or (ii) above shall become an Acquiring Person upon acquisition of an additional 1% of the Company's voting stock unless such acquisition of additional voting stock will not result in such person or group becoming an Acquiring Person by reason of such clause (i) or (ii)). Until the Distribution Date (or earlier redemption or expiration of the Rights), new Common Stock certificates issued after May 29, 1995 will contain a legend incorporating the Rights Agreement by reference. Until the Distribution Date (or earlier redemption or expiration of the Rights), the surrender for transfer of any of the Common Stock certificates outstanding as of May 29, 1995, with or without a copy of this Summary of Rights attached thereto, will also constitute the transfer of the Rights associated with the Common Stock represented by such certificate. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights ("Right Certificates") will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and such separate certificates alone will evidence the Rights from and after the Distribution Date. The Rights are not exercisable until the Distribution Date. The Rights will expire at the close of business on May 19, 2005, unless earlier redeemed by the Company as described below. The Preferred Stock is nonredeemable and, unless otherwise provided in connection with the creation of a subsequent series of preferred stock, subordinate to any other series of the Company's preferred stock. The Preferred Stock may not be issued except upon exercise of Rights. Each share of Preferred Stock will be entitled to receive when, as and if declared, a quarterly dividend in an amount equal to the greater of $1.00 per share or 100 times the cash dividends declared on the Company's Common Stock. In addition, the Preferred Stock is entitled to 100 times any non-cash dividends (other than dividends payable in equity securities) declared on the Common Stock, in like kind. In the event of the liquidation of the Company, the holders of Preferred Stock will be entitled to receive, for each share of Preferred Stock, a payment in an amount equal to the greater of $1,500 or 100 times the payment made per share of Common Stock. Each share of Preferred Stock will have 100 votes, voting together with the Common Stock. In the event of any merger, consolidation or other transaction in which Common Stock is exchanged, each share of Preferred Stock will be entitled to receive 100 times the amount received per share of Common Stock. The rights of Preferred Stock as to dividends, liquidation and voting are protected by anti-dilution provisions. The number of shares of Preferred Stock issuable upon exercise of the Rights is subject to certain adjustments from time to time in the event of a stock dividend on, or a subdivision or combination of, the Common Stock. The Exercise Price for the Rights is subject to adjustment in the event of extraordinary distributions of cash or other property to holders of Common Stock. Unless the Rights are earlier redeemed or the transaction is approved by the Board of Directors and the Continuing Directors, if the Company at any time after the Distribution Date were to be acquired in a merger or other business combination (in which any shares of Common Stock are changed into or exchanged for other securities or assets) or more than 50% of the assets or earning power of the Company and its subsidiaries (taken as a whole) were to be sold or transferred in one or a series of related transactions, the Rights Agreement provides that proper provision will be made so that each holder of record of a Right will from and after such date have the right to receive, upon payment of the Exercise Price, that number of shares of common stock of the acquiring company having a market value at the time of such transaction equal to two times the Exercise Price. In addition, unless the Rights are earlier redeemed, in the event that a person or group becomes the beneficial owner of 15% or more of the Company's voting stock (other than pursuant to a tender or exchange offer (a "Qualifying Tender Offer") for all outstanding shares of Common Stock that is approved by the Board of Directors, after taking into account the long-term value of the Company and all other factors they consider relevant in the circumstances), the Rights Agreement provides that proper provisions will be made so that each holder of record of a Right, other than the Acquiring Person (whose Rights will thereupon become null and void), will thereafter have the right to receive, upon payment of the Exercise Price, that number of shares of the Preferred Stock having a market value at the time of the transaction equal to two times the Exercise Price (such market value to be determined with reference to the market value of the Company's Common Stock as provided in the Rights Agreement). Fractions of shares of Preferred Stock (other than fractions which are integral multiples of one one-hundredth of a share) may, at the election of the Company, be evidenced by depositary receipts. The Company may also issue cash in lieu of fractional shares which are not integral multiples of one one-hundredth of a share. At any time on or prior to the close of business on the earlier of (i) the tenth day after the time that a person has become an Acquiring Person (or such later date as a majority of the Board of Directors and a majority of the Continuing Directors (as defined in the Rights Agreement) may determine) or (ii) May 19, 2005, the Company may redeem the Rights in whole, but not in part, at a price of $.001 per Right (the "Redemption Price"). The Rights may be redeemed after the time that any Person has become an Acquiring Person only if approved by a majority of the Continuing Directors. Immediately upon the effective time of the action of the Board of Directors of the Company authorizing redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price. For as long as the Rights are then redeemable, the Company may, except with respect to the redemption price or date of expiration of the Rights, amend the Rights in any manner, including an amendment to extend the time period in which the Rights may be redeemed. At any time when the Rights are not then redeemable, the Company may amend the Rights in any manner that does not materially adversely affect the interests of holders of the Rights as such. Amendments to the Rights Agreement from and after the time that any Person becomes an Acquiring Person requires the approval of a majority of the Continuing Directors (as provided in the Rights Agreement). Until a Right is exercised, the holder, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends. A copy of the Rights Agreement has been filed with the Securities and Exchange Commission as an Exhibit to a Current Report on Form 8-K dated June 7, 1995. A copy of the Rights Agreement is available free of charge from the Company. This summary description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement which is incorporated in this summary description herein by reference.