Axonyx Initiates Second Phase III Alzheimer's Disease Trial with Phenserine.

NEW YORK -- Axonyx Inc. (NASDAQ: AXYX) today announced the initiation of its second Phase III international clinical trial with its lead Alzheimer's disease drug, Phenserine. The Investigator's Meeting that will be held June 18th and 19th in Amsterdam, Netherlands signals the formal start of this Phase III clinical trial and patient recruitment will commence immediately following the meeting. This randomized placebo-controlled double-blind clinical trial will evaluate the safety and efficacy of two different dosages of Phenserine in 450 mild to moderate Alzheimer's disease (AD) patients following a six-month treatment period. The company is taking advantage of the regulatory approvals already granted in Europe for its ongoing clinical development program and this second Phase III trial will be conducted at multiple clinical sites throughout Europe and Israel. The company intends to include clinical trial sites in the United States in this international trial upon approval by the United States FDA (US FDA) of the submitted data package currently under review.

This second Phase III trial will recruit patients to randomly receive Phenserine 10mg twice daily, Phenserine 15mg twice daily or placebo. Axonyx initiated the first randomized, placebo-controlled double-blind Phase III trial in June of 2003 and data from this trial are anticipated to be ready for analysis by the end of 2004. Patients in both trials undergo testing with the standard memory and cognition tests that are the efficacy endpoints required by the US FDA and European regulatory authorities for potential marketing approval. As with all of the ongoing clinical trials that Axonyx conducts, all patients completing each 6-month clinical trial treatment period are offered the opportunity to continue to receive Phenserine for an additional 6-month period in an associated extension trial. These extension trials provide the company with long-term safety and efficacy data.

Based on the data packages of the marketed products in the same drug class as Phenserine, Axonyx anticipates initiating one additional international Phase III safety and efficacy clinical trial in the near future. This trial will ensure that sufficient data is provided to the US FDA and European Regulatory Agencies to meet their patient drug exposure and safety requirements. Regulatory Agencies, including the US FDA, generally require that two Phase III trials have positive safety and efficacy outcomes in order for an NDA or its equivalent to be potentially approvable.

Phenserine is an acetylcholinesterase and beta amyloid precursor protein (B-APP) inhibitor that is being developed by Axonyx for the treatment of mild to moderate AD patients. Phenserine is currently also undergoing clinical testing in a Phase IIB study designed to evaluate Phenserine's ability to lower the levels of the beta-amyloid precursor protein and beta-amyloid in the plasma and cerebrospinal fluid of mild to moderate AD patients. The presence of toxic beta-amyloid in the brains of AD patients is considered by many experts to be a key pathological event in the causation as well as the progression of AD.

"The initiation of this second Phase III trial signifies our ongoing confidence and commitment to bring Phenserine to approvable NDA status," stated Gosse B. Bruinsma, M.D., President & Chief Operating Officer of Axonyx Inc., "Our clinical development program is on course and we are optimistic that the final data package will support the potential approval of Phenserine."

About Axonyx

Axonyx Inc. is a U.S.-based biopharmaceutical company engaged in the acquisition and development of proprietary pharmaceutical compounds for the treatment of Central Nervous System disorders.

This press release may contain forward-looking statements or predictions. These statements represent our judgment to 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 SEC, specifically Axonyx's annual report on Form 10-K. Axonyx cannot assure that the Phase IIb and/or the Phase III clinical trial, or others, if any, with Phenserine will prove successful, that the safety and efficacy profile of Phenserine exhibited in the previous small Phase II trial will remain the same in the Phase IIb clinical trial, or future clinical trials, if any, that the preclinical results related to the regulation of beta-APP will be substantiated by the Phenserine Phase IIb clinical trial and that Phenserine will be able to slow the progression of Alzheimer's disease ,that the Phase IIb clinical trial data will differentiate Phenserine from the currently marketed drugs, that the efficacy results of the Phase III trial will prove pivotal, that Axonyx will obtain the necessary financing to complete the Phase III Phenserine trials, that the Company's development work on Phenserine will support an NDA filing, that the results of the Phase III trials will allow Phenserine to be approved by the FDA, that the FDA will grant marketing approval for Phenserine, that if Phenserine is approved by the FDA, it will prove competitive in the market, and that Axonyx will obtain licensing or corporate partnership agreements that will enable acceleration of the development of and optimize marketing opportunities for, Phenserine, or that Axonyx will be able to advance any other potential memory enhancing compound toward IND status. 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.