Affymax to complete Hematide Phase 3 clinical study by the end of 2009

Affymax, Inc. (Nasdaq:AFFY) today announced that it has notified clinical trial sites to complete treatment of patients in the Phase 3 clinical program for the investigational drug, Hematide, by the end of 2009. The company expects a period of approximately four months for data gathering and analysis, prior to reporting topline results in the second quarter of 2010. This amended timeline is not expected to affect the timing for New Drug Application (NDA) submission. The Phase 3 clinical program involves approximately 2,600 chronic renal failure patients at more than 400 clinical trial sites.

“While some additional patient follow-up will extend our time to study completion, we believe these collected data will further strengthen and support our statistical plan,” said Arlene Morris, president and chief executive officer of Affymax, Inc. “However, consistent with our previous guidance, we still expect to submit an NDA for Hematide in chronic renal failure in 2010 if all goes as planned.”

The Hematide Phase 3 program consists of four open-label, randomized controlled clinical trials in the U.S. and Europe, including two trials in patients on dialysis and two trials in patients not on dialysis. The trials in non-dialysis patients, called PEARL 1 and PEARL 2, are evaluating the safety and efficacy of Hematide compared to darbepoetin alfa in correcting anemia and maintaining hemoglobin levels over time.

In dialysis patients, the trials, called EMERALD 1 and EMERALD 2, are evaluating the safety and efficacy of Hematide and its ability to maintain hemoglobin levels in the target range when patients are switched from epoetin alfa or epoetin beta to Hematide.

Analysis of efficacy for each study is based on assessments of non-inferiority to the comparator drugs. The primary efficacy endpoint is the mean change in hemoglobin from baseline. The hemoglobin target range is 11-12 g/dL for studies in non-dialysis patients and 10-12 g/dL for studies in dialysis patients. In all studies, Hematide is dosed once every four weeks while comparator drugs are dosed more frequently in accordance with their respective product labels. Treatment in each study is planned until the last patient has been in the study for approximately 52 weeks. The primary assessment of safety will be an analysis of non-inferiority to comparator drugs using a composite cardiovascular endpoint from a safety database pooled from all four Phase 3 trials. The duration of the Phase 3 trials depends on a sufficient number of cardiovascular safety events for statistical analysis.