Affymax(R) Announces Phase 2 Clinical Trial Results of Once-Per-Month Hematide(TM) for the Treatment of Anemia in Patients with Early- and End-Stage Chronic Kidney Disease.

PALO ALTO, Calif. -- Affymax, Inc. (Nasdaq:AFFY) today announced results to date from two separate Phase 2 clinical trials of Hematide[TM] in dialysis and non-dialysis chronic kidney disease (CKD) patients. The data showed that in treatment naove, non-dialysis patients Hematide could correct anemia when administered monthly at an appropriate dose. Similarly, the data in dialysis patients previously treated with three-times weekly Epoetin Alfa demonstrated that mean hemoglobin (Hgb) levels could be maintained at clinically acceptable levels following a switch to once monthly dosing of Hematide at an appropriate dose. The data were presented by Iain C. Macdougall, M.D. at the World Congress of Nephrology meeting being held in Rio de Janeiro.

"These data show that Hematide results in appropriate management of hemoglobin levels in a broad spectrum of patients with CKD from early-stage patients not on dialysis to patients with end-stage renal disease requiring continuous dialysis support," said Dr. Macdougall. "Anemia is a pervasive problem in the chronic kidney disease patient population. Being able to manage and control anemia allows treating physicians to focus attention on management of the patient's underlying renal disease."

At the time of the presentation, the data generated to date were from two multi-center, open-label studies that have enrolled a total of 304 patients. Safety data were based on the entire patient population, while pharmacodynamic data were based on 180 patients who had mostly completed six months of treatment at European and U.S. sites.

Of those, 90 treatment naove CKD patients who were not on dialysis in the correction study were treated with Hematide once every four weeks. The mean Hgb level was 10.2 g/dL at study entry and was increased to greater than 11 g/dL following an initial dose of Hematide. In the maintenance-conversion study, 90 patients previously treated with Epoetin Alfa were switched to Hematide once every four weeks. The mean baseline Hgb level, which was 11.5 g/dL at baseline, was maintained within +/- 1 g/dL at the end of six months of treatment. Hematide was generally well tolerated with an adverse event profile consistent with the chronic kidney disease patient population.

Anne-Marie Duliege, M.D., vice president, Clinical, Medical and Regulatory Affairs for Affymax added, "As we prepare for Phase 3 clinical trials for Hematide, these data support our goal to evaluate the product in a broad CKD patient population. The Phase 3 studies will assess the safety and efficacy of Hematide in these patient populations and will generate sufficient clinical data to assist physicians in optimizing anemia management in their patients."

About Hematide

Hematide is a novel synthetic, pegylated peptide that binds to and activates the erythropoietin receptor. The product is being developed for treatment of anemia in chronic kidney disease and cancer.

About Affymax, Inc.

Affymax, Inc. is a biopharmaceutical company developing novel peptide-based drugs to improve the treatment of serious and often life-threatening conditions. Affymax's lead product candidate, Hematide[TM], is currently in Phase 2 clinical trials for the treatment of anemia associated with chronic kidney disease and cancer. For additional information, please visit www.affymax.com.

This release contains forward-looking statements, including statements regarding the timing, design and results of the Company's clinical trials and drug development program, the timing and likelihood of the commercialization of Hematide. The Company's actual results may differ materially from those indicated in these forward-looking statements due to risks and uncertainties, including risks relating to the continued safety and efficacy of Hematide in clinical development, the potential for once per month dosing, regulatory requirements and approvals, research and development efforts, industry and competitive environment, intellectual property rights and disputes and other matters that are described in the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission. Investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release. The Company undertakes no obligation to update any forward-looking statement in this press release.