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(1)

In the event of a stock split, stock dividend, or similar transaction involving the Company’s common stock, in order to prevent dilution, the number of shares registered shall automatically be increased to cover the additional shares in accordance with Rule 416(a) under the Securities Act.

(2)

Estimated solely for the purpose of calculating the amount of the registration fee in accordance with Rule 457(c) under the Securities Act of 1933 based on the average of the high and low sales prices of the Registrant’s common stock on the Nasdaq Stock Market on January 15, 2003.

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Out-license or sell some or all of our intellectual, technological, and/or tangible property not presently contemplated and at terms that we believe would not be favorable to us;

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Further reduce the size of our workforce, including the number of our scientific personnel;

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Reduce the scope and nature of our research and drug development activities; and

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Terminate operating leases and other contractual arrangements.

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continued scientific progress in research and development to identify and develop or obtain additional product candidates; the costs and progress of preclinical and clinical testing of our anti-cancer drugs and additional drug candidates;

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cost involved in filing, prosecuting and enforcing patent claims;

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effect of competing technological developments;

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cost of manufacturing scale-up;

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cost of commercialization activities;

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time and cost involved in obtaining regulatory approvals; and

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our ability to establish collaborative and other arrangements with third parties, such as licensing and manufacturing agreements.

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•

pursuing new patents for existing products which may be granted just before the expiration of one patent which could extend patent protection for a number of more years or otherwise delay the launch of generics;

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using the Citizen Petition process to request amendments to FDA standards;

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seeking changes to the United States Pharmacopeia, an organization which publishes industry recognized compendia of drug standards; and

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attaching patent extension amendments to non-related federal legislation.

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•

product recalls or seizures;

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injunctions;

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civil penalties;

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criminal prosecution;

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refusals to approve new products and withdrawal of existing approvals; and

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enhanced exposure to product liabilities.

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(1)

For the purposes of calculating percent of class beneficially owned by a holder, shares of common stock which may be issued to that holder within 60 days of January 17, 2003 are deemed to be outstanding.

(2)

Assumes the sale by the selling stockholders of all of the shares of common stock available for resale under this Prospectus.

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ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

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block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;

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purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

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an exchange distribution in accordance with the rules of the applicable exchange;

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privately negotiated transactions;

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short sales;

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broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share;

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a combination of any such methods of sale; and

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any other method permitted pursuant to applicable law.

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the name of each such selling stockholder and of the participating broker-dealer(s);

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the number of shares involved;

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the price at which such shares were sold;

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the commissions paid or discounts or concessions allowed to such broker-dealer(s), where applicable;

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that such broker-dealer(s) did not conduct any investigation to verify the information set out or incorporated by reference in this prospectus; and

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other facts material to the transaction.

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•

prior to such date the board of directors of the corporation approved either the “business combination” or the transaction which resulted in the stockholder becoming an “interested stockholder,”

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upon consummation of the transaction which resulted in the stockholder becoming an “interested stockholder,” the “interested stockholder” owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding those shares owned (1) by persons who are directors and also officers and (2) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer, or

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at or subsequent to such time the “business combination” is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not be written consent, by the affirmative vote of a least 66 2/3% of the outstanding voting stock which is not owned by the “interested stockholder.”

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Our annual report on Form 10-K for the fiscal year ended December 31, 2001, filed on April 2, 2002;

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Our quarterly report on Form 10-Q for the quarters ended March 31, 2002, June 30, 2002, and September 30, 2002, filed on May 15, 2002, August 19, 2002, and November 13, 2002, respectively;

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Our current reports on Form 8-K filed on March 14, 2002, March 27, 2002, April 25, 2002, April 29, 2002, May 1, 2002, May 7, 2002, June 3, 2002, June 7, 2002, June 18, 2002 (dated June 7, 2002), June 19, 2002, July 12, 2002, August 23, 2002, September 6, 2002, October 1, 2002, November 21, 2002, November 26, 2002 (dated December 23, 2002), December 19, 2002, December 23, 2002, December 23, 2002 (dated December 23, 2002), January 2, 2003 and January 17, 2003;

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Our definitive proxy statement filed on April 30, 2002, pursuant to Section 14 of the Exchange Act in connection with our 2002 Annual Meeting of Stockholders, and our definitive proxy statements filed on July 12, 2002, August 9, 2002 and August 23, 2002 pursuant to Section 14 of the Exchange Act in connection with our 2002 Special Meeting of Stockholders;

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The description of our common stock contained in the Registration of Securities of Certain Successor Issuers filed pursuant to Section 12(g) of the Exchange Act on Form 8-B on June 27, 1997, including any amendment or reports filed for the purpose of updating such description;

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The description of our Rights to Purchase Series B Junior Participating Preferred Stock contained in the Registration of Certain Classes of Securities filed pursuant to Section 12(g) of the Exchange Act on Form 8-A on December 26, 2000, including any amendment or reports filed for the purpose of updating such description.

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*

Estimated.

(1)

(i)    To include any prospectus required by Section 10(a)(3) of the Securities Act;

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(ii)

To reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

(iii)

To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

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