Affymax Announces FDA Advisory Committee to Review Peginesatide

Oncologic Drugs Advisory Committee Meeting Scheduled for December 7, 2011

PALO ALTO, Calif.--(BUSINESS WIRE)-- Affymax, Inc. (Nasdaq:AFFY) today announced that the U.S. Food and Drug Administration's (FDA) Oncologic Drugs Advisory Committee (ODAC) will review the New Drug Application (NDA) for peginesatide proposed for the treatment of anemia associated with chronic kidney disease (CKD) in adult patients on dialysis on December 7, 2011 during the afternoon session. The FDA has established an action date of March 27, 2012 under the Prescription Drug User Fee Act (PDUFA).

Erythropoiesis stimulating agents (ESAs) are reviewed by the Office of Hematology and Oncology Products (OHOP). As such, FDA has designated ODAC for the review of peginesatide. Information related to the meeting can be found on the U.S. Office of the Federal Register Website at: http://www.fda.gov/RegulatoryInformation/Dockets/FR/default.htm.

The company intends to begin a self-imposed quiet period on November 16, 2011 in anticipation of receipt of FDA briefing documents, and this quiet period will continue until after the Advisory Committee meeting is completed.

If approved, peginesatide will be the first once-monthly ESA available for the treatment of anemia associated with CKD patients on dialysis in the United States.

Peginesatide is a synthetic, PEGylated peptidic compound that binds to and stimulates the erythropoietin receptor and thus acts as an ESA. The NDA included data from two Phase 3 studies (EMERALD 1 and 2) that evaluated the efficacy and safety of peginesatide, dosed once every four weeks, compared to epoetin alfa or epoetin beta, dosed more frequently (according to the product labels) in maintaining hemoglobin (Hb) levels in CKD patients on dialysis with anemia. In the studies, over 1,600 CKD patients on dialysis who were receiving stable doses of epoetin were randomized to receive once-monthly peginesatide or continue treatment with epoetin. The EMERALD findings suggested that once-monthly peginesatide was comparable to epoetin in maintaining Hb levels in CKD patients on dialysis with anemia with a similar adverse event rate. The most common adverse events reported in the clinical studies were diarrhea, cough, dyspnea, nausea, and muscle spasm. A similar frequency of serious adverse events was reported between the EMERALD treatment groups.

About Peginesatide

Affymax and Takeda are collaborating on the development of peginesatide and plan to co-commercialize the product if approved in the United States. Takeda has exclusive rights to develop and commercialize the product outside the United States. The peginesatide Phase 3 clinical program was the largest to support the registration of an ESA for the treatment of anemia in CKD and the first to prospectively evaluate the cardiovascular safety of an ESA via an analysis of independently adjudicated cardiovascular events.

About Anemia in Chronic Kidney Disease

Anemia is a common complication in CKD, because the impaired kidneys are not able to produce enough erythropoietin, the hormone that promotes the production of oxygen-carrying red blood cells. Research has shown that anemia impacts the overall health and well being of CKD and dialysis patients and is associated with increased rates of hospitalization and mortality. 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.

ESAs, which stimulate red blood cell production, are commonly prescribed to treat anemia of CKD. According to the Centers for Medicare and Medicaid Services, more than 95 percent of patients on dialysis in the U.S. are currently receiving ESA treatment for anemia of CKD.