Affymax(R) Reports Phase 2 Clinical Dose Ranging Results of Once-Per-Month Hematide(TM) for the Treatment of Anemia.

PALO ALTO, Calif. -- Affymax, Inc. (Nasdaq:AFFY) today announced that additional Phase 2 clinical trial results for Hematide[TM] were presented at the European Renal Association-EDTA Congress being held in Barcelona, Spain by Iain C. Macdougall, M.D., a Hematide investigator from Kings College, London. Dr. Macdougall's poster included data in previously-treated dialysis patients and treatment naive, non-dialysis patients which demonstrated that mean hemoglobin (Hgb) levels could be maintained and corrected, respectively, with once monthly Hematide.

Specifically, the data showed that in non-dialysis patients an initial range of doses from .025 mg/kg to .075 mg/kg of Hematide, in conjunction with dose adjustments, is adequate to increase Hgb in anemic patients with renal failure when administered monthly. In addition, intravenous and subcutaneous dosing appeared to result in a similar Hgb increase.

"These data support further investigation of the versatility and flexibility of once-per-month Hematide in terms of starting doses and route of administration," said Robert Naso, Ph.D., executive vice president of Research and Development at Affymax. "These results demonstrate that a narrow target range of hemoglobin levels can be reached with different initial Hematide doses. We are pleased to have such thorough evaluation of the product as we prepare for pivotal Phase 3 clinical trials."

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 179 patients who had mostly completed six months of treatment at European and U.S. clinical sites. Of those, 89 treatment-naive 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 >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 +/- 1.0 g/dL at the end of six months of treatment. Hematide was generally well tolerated and compatible with adverse events usually observed in patients with chronic kidney disease, with 6 percent of patients reporting adverse events possibly related to Hematide such as fatigue, rash and hypertension and 0.7 percent of patients reporting serious adverse events possibly related to Hematide (one transient ischemic attack in a patient with history of atrial fibrillation, and one moderate infusion reaction in a patient who responded to outpatient intervention).

About Hematide

Hematide is a novel synthetic, pegylated peptidic compound that binds to and activates the erythropoietin receptor. The product is being developed for treatment of anemia in patients with chronic renal failure and cancer patients receiving chemotherapy.

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 renal failure 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 Quarterly Report on Form 10-Q 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.