In February, Affymax of Palo Alto, California, and its partner Takeda of Osaka voluntarily withdrew Omontys, the peptide erythropoietin mimetic, from the market following 19 serious hypersensitivity reactions, including three deaths. Omontys was approved by the US Food and Drug Administration (FDA) in March of 2012 for treating anemia in patients on dialysis with chronic kidney disease (CKD). With the loss of its only product, Affymax has cut its workforce by 75% and is “evaluating strategic alternatives” according to a company press release. The cause of the severe reaction, which occurred within 30 minutes of the first dose of the drug, remains mysterious. According to Affymax's chief medical officer Anne-Marie Duliege, the incidence of hypersensitivity reactions was the same before and after marketing (0.2%), but the reactions observed after approval, when one-third of patients required immediate medical intervention, were more severe than during clinical trials. Erythropoietin stimulating agents (ESA) have been under increased scrutiny since 2011 when their use linked to cardiovascular problems; Affymax did scale back its target population in its new drug application, eliminating patients with less severe kidney dysfunction, who showed a greater incidence of cardiovascular reactions than with its competitor Amgen's long-acting EPO, Aranesp (darbepoetin alfa). This raised a red flag for Steven Nissen of Cleveland Clinic, in Ohio, the one dissenting vote of the 16-member FDA Oncologic Drugs Advisory Committee panel that reviewed Omontys. “There's no reason to believe that the drug would be helpful in the group that had a little worse kidney function and harmful in the group that had a little bit better kidney function,” he said.