A Food and Drug Administration advisory panel voted 15-1 on Wednesday, with one abstention, that peginesatide's benefits outweighed its risks for such patients.
If approved by the FDA, the once-monthly injection could capture a share of the $3 billion U.S. market for anemia drugs used for kidney dialysis patients, currently dominated by Amgen Inc's blockbuster Epogen.
The FDA usually follows the advice of its advisory panels, and is set to make the final decision on peginesatide by March 27.
"I think the compelling evidence today is that we don't have a reason to say no to this drug in the dialysis setting," said Dr. Wyndham Wilson, chair of the panel and chief of the lymphoma therapeutics section at the National Cancer Institute.
Affymax, which developed the drug with partner Takeda Pharmaceutical Co Ltd, is also expected to price its product below Epogen.
Shares of Affymax were halted on Nasdaq pending the panel's outcome.
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 the body to make red blood cells.
Peginesatide belongs to a class of medicines known as erythropoiesis stimulating agents (ESAs). They are used to boost red blood cells in anemia patients to help avoid the need for blood transfusions.
Late-stage trials of the Affymax drug, released in June, had 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.
This led the company to seek approval of the drug only for patients who were on dialysis.
The key question for the panel was whether safety issues in the non-dialysis patients would also show up in dialysis patients, or whether the two populations were too different.
"Studies are a trade-off between absolutely perfect design and practicality," said panel member Dr. Louis Diehl, professor at the Duke University Medical Center. He said he voted in favor of the drug because of its overall efficacy and safety.
"I think the ease of administration will provide benefit to the patient," he added.
Nurses and doctors who spoke during the public hearing focused on the benefits of once-monthly dosing -- less frequent than Epogen's -- which could improve patient safety from fewer dosage errors and leave more time for patient care.
But Dr. Steven Nissen, a panel member and frequently an outspoken advocate for patient safety, voted against the drug.
"The time has come to search our souls and decide how much risk are we willing to take for the convenience factor," said Nissen, who chairs the department of cardiovascular safety at the Cleveland Clinic.
"Will we in five years come back and find out that there was something going on here that we were learning in the non-dialysis population, that will emerge in the dialysis population?
"Those views are weighing heavily on me," he said.
(Reporting By Anna Yukhananov)