Collateral Therapeutics In Stock Deal

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Exhibit 99.3

Schering AG to acquire US-biotech company
Collateral Therapeutics in stock deal

Berlin, Germany and San Diego, CA (March 20, 2002) Schering AG (NYSE:SHR; FSE:SCH) announced today that they have entered into an agreement under which they will acquire Collateral Therapeutics, Inc. (NASDAQ:CLTX) in a stock-for-stock acquisition.

Collateral Therapeutics discovers and develops innovative gene therapy products for the potential treatment of cardiovascular diseases, by promoting and enhancing angiogenesis, a natural biological process that results in the growth of additional blood vessels which can carry blood flow to oxygen-deprived tissues.

Schering AG is the exclusive worldwide licensee for Collateral's two lead products, preliminarily called Generx ? (Ad5FGF-4,) in Phase IIb/III clinical trials, and Genvascor ? (Ad5.1FGF-4,) which is currently in Phase I. They are potential treatments for stable exertional angina due to coronary artery disease and peripheral vascular disease.

Schering AG, which already owns 12% of Collateral Therapeutics' shares, will acquire the remaining outstanding shares at an estimated value of US $140 million in exchange for Schering AG's American Depositary Receipts ("ADRs"). At the closing of the transaction, each Collateral Therapeutics share will be converted into the right to receive 0.1847 of Schering ADRs. Certain Collateral stockholders who own an aggregate of approximately 26.7% of the outstanding shares of Collateral Therapeutics common stock have agreed to vote in favor of the merger. The transaction, expected to close the third quarter of 2002, is subject to approval by Collateral Therapeutics' stockholders, regulatory authorities and other customary closing conditions.

"This acquisition reinforces Schering's strategic drive to enrich its portfolio with specialized treatments. Collateral Therapeutics is a leader in the discovery and development of innovative gene therapy products for the potential treatment of cardiovascular diseases." said Dr. Hubertus Erlen, chairman of Schering AG's executive board. "Our biopharmaceutical development expertise and our ability to bring products to an international marketplace is complemented by the scientific concepts advanced by Collateral's discovery team," he said.

"Our six-year collaboration has advanced to the stage that we foresee filing for regulatory approval of treatments utilizing the Collateral Therapeutics' gene therapy technology," observed Professor Dr. Guenter Stock, Schering AG's chief scientific officer and member of the executive board. "By creating new treatment options in cardiology, the potential for patients is great. This acquisition broadens and enhances our chances of making a major contribution for regenerative medicines."

"This development is pivotal as we accumulate data affirming the scientific rationale upon which the company was founded. Schering AG's commitment to Collateral Therapeutics is a tribute to our scientists and staff," said Jack W. Reich, Ph.D. Collateral's chairman and chief executive officer. "As part of the Schering AG organization, we plan to continue to develop cardiovascular gene therapies that we believe hold the potential to transform the practice of cardiovascular care and treatment."

In a separate agreement, Schering AG and Collateral entered into an amendment to their 1996 collaboration agreement under which Collateral will receive a cash payment of $12 million in exchange for a 2 percent reduction in the level of royalties payab ...