Affymax Completes Enrollment in Phase 3 Program for Hematide in Chronic Renal Failure with Completion of Enrollment in EMERALD 2

Affymax Completes Enrollment in Phase 3 Program for Hematide in Chronic Renal Failure with Completion of Enrollment in EMERALD 2, the Final of Four Phase 3 Clinical Trials of Hematide

All Four Pivotal Trials Now Fully Enrolled to Support Planned NDA Submission

PALO ALTO, Calif.--(BUSINESS WIRE)--Affymax, Inc. (Nasdaq:AFFY) today announced that enrollment has been completed in the remaining Phase 3 clinical trial of its lead investigational therapy, HematideTM, which is being evaluated for the treatment of anemia in chronic renal failure patients. EMERALD 2 is fully enrolled with over 800 dialysis patients, collectively, from over 90 sites in the United States and Europe.

"With PEARL 1 enrollment completed in July, PEARL 2 in October, EMERALD 1 just a week ago and now EMERALD 2 fully enrolled, we have now completed enrollment in our pivotal Phase 3 program for Hematide for the treatment of anemia in chronic renal failure patients," said Arlene Morris, president and chief executive officer at Affymax. "The clock now starts for the 52 week treatment period in EMERALD 2, which aligns us for composite data release from all four studies in early 2010, assuming sufficient data collection. Consistent with our previous guidance, we expect to submit a New Drug Application for Hematide in chronic renal failure in 2010 if all goes as planned."

The Hematide Phase 3 program, involving a total of approximately 2,600 chronic renal failure patients, 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 a corrected 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 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. Assessment of safety will include 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 assumes observance of a sufficient number of safety events for statistical analysis.

About Hematide

Hematide is a novel synthetic, PEGylated peptidic compound that binds to and activates the erythropoietin receptor and thus acts as an erythropoiesis stimulating agent (ESA).

Affymax and Takeda Pharmaceutical Company Limited are collaborating on the development of Hematide and plan to co-commercialize the product in the United States. The product, upon approval, will be commercialized in the European Union by Takeda. Affymax is conducting Phase 3 clinical trials for Hematide to treat anemia associated with chronic renal disease.

About Anemia in Chronic Renal Failure (CRF)

Anemia in CRF affects many individuals with Chronic Kidney Disease (CKD). According to the National Kidney Foundation, 20 million Americans - 1 in 9 U.S. adults - have CKD. Anemia develops in the early stages of CKD and worsens as patients progress towards total kidney failure and need a dialysis machine to eliminate waste and water from their blood. In severe or prolonged cases of anemia, the lack of oxygen in the blood can cause serious and sometimes fatal damage to the heart and other organs. Benefits of anemia correction in patients with CKD include decreased morbidity, hospitalization, and mortality.1

About Affymax, Inc.

Affymax, Inc. is a biopharmaceutical company developing novel drugs to improve the treatment of serious and often life-threatening conditions. For additional information, please visit www.affymax.com [1].

This release contains forward-looking statements, including statements regarding the success of the collaboration, timing, design and results of the Company's clinical trials and drug development program and 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, the timing of patient accrual and treatment in ongoing and planned clinical studies, regulatory requirements and approvals, research and development efforts, industry and competitive environment, intellectual property rights and disputes and other matters that are described in Affymax'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.