Affymax investors bullish on FDA review of Amgen anemia drug rival

Facing an expert panel review for peginesatide on Wednesday, FDA staffers gave Affymax ($AFFY) a solid boost in confidence this morning with an agency review that backed the once-monthly anemia treatment as equivalent to Amgen's ($AMGN) blockbuster treatments Epogen and Aranesp. And investors quickly picked up on the positive spin, boosting the biotech's stock more than 25% this morning.

"Data from the clinical program support the efficacy of peginesatide administered once monthly for the treatment of anemia of CKD in dialysis patients," the staffers noted in a detailed review of the data. "The Phase III Dialysis Studies 12 and 14 demonstrated peginesatide could be used to maintain stable Hb levels as successfully as epoetin."

The agency has its reservations about the drug's safety, though, and wants the committee to take a close look at the benefits and risks for patients with chronic kidney disease, "given the safety findings and in light of the prior history with agents that stimulate the erythropoietin receptor." Affymax and its partner Takeda are seeking approval of the drug for CKD patients on dialysis. But as Adam Feuerstein at The Street noted this morning, the FDA's safety concerns appear relatively muted in the report, which helped to further ignite the biotech's share price.

Agency reviews typically contain a sharp focus on any safety or efficacy concerns for a new drug. And investors have been acutely sensitive to some late-stage data on the drug's cardio risks seen in a group of patients. Today they seem to be at least temporarily satisfied that Affymax has taken one more step toward a potential approval for the first direct competitor to Amgen's more frequently administered treatments.

- get the FDA review (.pdf)
- here's the story from The Street
- read the Bloomberg report

Special Report: Amgen - Biotech's Biggest Spenders 2011

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