Axonyx Announces Milestone Payment from Serono after Initiation of Clinical Trial in Alzheimer's.

Business Editors/Health/Medical Writers

NEW YORK--(BUSINESS WIRE)--April 24, 2003

Axonyx Inc. (NASDAQ: AXYX) today announced a milestone payment of $1 million from Serono S.A. (NYSE: SRA and virt-X: SEO) under the terms of a license agreement for beta-sheet breaker technology that was signed in September 2000. The milestone payment was triggered when Serono initiated a Phase I clinical trial with a beta-sheet breaker peptide for the potential treatment of Alzheimer's disease.

The peptide technology is designed to inhibit toxic beta-amyloid sheets (plaques), which are believed to be a causative pathologic event in patients with Alzheimer's disease. In preclinical studies using transgenic mice, the peptide significantly reduced both amyloid plaques (by approximately 50%) and nerve cell death. The Phase I clinical trial is designed to test the safety, tolerability and the pharmacokinetics of the peptide in healthy volunteers following intra-venous or sub-cutaneous administration of single and multiple dosages.

"Serono's achievement in starting this clinical trial is a significant milestone in the development of the Axonyx beta-sheet breaker technology," stated Marvin S. Hausman, M.D., President and Chief Executive Officer of Axonyx Inc. "This approach has the potential of being a breakthrough treatment for a devastating disease such as Alzheimer's that has seen few new developments recently."

Serono Conference Call Details

Serono's First Quarter 2003 Results Conference Call will take place today, April 24th at 9am ET. To participate, please go to their homepage, www.serono.com and click on the related ticker announcement and follow the instructions. The webcast playback will be available until close of business on May 16th, 2003 via the hyperlink on the Serono homepage. To link by phone please dial one of the numbers listed below between 5 and 10 minutes before the conference is scheduled to begin:

1.412.858.4600 (From the U.S.)

0207.866.4111 (From the U.K.)

091.610.5600 (From Switzerland)

+41.91.610.5600 (From elsewhere)

The phone playback will be available 1 hour after the conference call and until April 30th, 2003. Please dial one of the numbers listed below and enter the PIN CODE 519#.

1.412.858.1440 (From the U.S.)

0207.866.4300 (From the U.K.)

091.612.4330 (From Switzerland)

+41.91.612.4330 (From elsewhere)

About Axonyx

Axonyx Inc. is a U.S.-based biopharmaceutical company engaged in the acquisition and development of proprietary pharmaceutical compounds and new technologies useful in the diagnosis and treatment of Alzheimer's disease, human memory disorders and prion-based illnesses such as Mad Cow Disease.

This press release may contain forward-looking statements or predictions. These statements represent our judgment as of this date and are subject to risks and uncertainties that could materially affect the Company, including those risks and uncertainties described in the documents Axonyx files from time to time with the Securities and Exchange Commission, specifically Axonyx's Annual Report on Form 10-K. There can be no assurance that Serono will continue to proceed with the development of drug compounds based on the amyloid inhibitory peptide technology covered by the license agreement with Axonyx, that these clinical trials or future clinical trials, if any, based on the amyloid inhibitory peptide technology will prove successful, or that further development milestones that trigger payments by Serono to Axonyx will occur. Axonyx undertakes no obligation to publicly release the result of any revisions to such forward-looking statements that may be made to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.