(Reuters) - Drug reviewers found Affymax Inc’s treatment for anemia in dialysis patients with chronic kidney disease to be as effective as market-leading drugs by Amgen Inc, but cautioned they were not convinced of its safety.
In review documents released on Monday, U.S. Food and Drug Administration staff said uncertainty over the safety of Affymax’s treatment, known as peginesatide, remained a “major concern” from its clinical trials.
But the reviewers also found the Affymax drug similarly effective as Amgen’s Epogen and Aranesp when it came to maintaining target hemoglobin levels. In dialysis patients, the drug had a similar safety profile to Epogen.
Affymax shares jumped 19 percent to $6.23 on Nasdaq.
“It’s as good as it gets for Affymax review documents,” said Dr. Christopher James, analyst at boutique investment bank MLV & Co.
Affymax’s injection peginesatide, developed in partnership with Takeda Pharmaceutical Co Ltd, aims to capture a significant share of the $3 billion U.S. market for anemia drugs used for kidney dialysis patients, currently dominated by Amgen’s big-selling Epogen product.
Late-stage trials of the Affymax drug, released in June, met their main goal but showed a higher rate of cardiovascular events, including death and stroke, in patients who were suffering from chronic renal failure but were not on dialysis.
Although Affymax is not seeking approval for use in non-dialysis patients, the discrepancy in results had raised red flags, especially given that people on dialysis are generally sicker.
FDA reviewers said the non-dialysis population in the Affymax drug trials had health problems that may have been unfavorable for peginesatide treatment arm but the link is uncertain.
“The FDA describes the well known safety signal in the non-dialysis population,” ISI Group analyst Dr. Mark Schoenebaum wrote in a note. “We think Wednesday’s panel could go either way.”
Anemia is a condition in which the body does not have enough oxygen-carrying red blood cells. Most people with kidney disease will develop anemia as kidneys fail to produce enough of the hormone that signals to the body to make red blood cells. Affymax
A panel of expert advisers to the FDA will review the drug on December 7, with a final decision from the agency expected by March 27.
Reporting by Alina Selyukh in Washington; Editing by Gerald E. McCormick