WASHINGTON -- Shares of ISIS Pharmaceuticals rose in premarket trading Friday after federal health regulators voted in favor of the company's experimental cholesterol drug Kynamro, despite serious safety concerns uncovered in testing.
Shares of Carlsbad, Calif.-based ISIS rose 25 cents, or 2.6 percent, to $9.87 in premarket dealings.
On Thursday the Food and Drug Administration's metabolic drug committee voted 9-6 in favor of approving the company's drug, which is designed to treat a rare genetic condition that causes very high levels of "bad" LDL cholesterol. The FDA is not required to follow the committee's advice, though it often does.
The positive vote came despite potential links between Kynamro and cancer seen in company trials. In its review posted ahead of the meeting, the FDA said Kynamro was linked to both benign and cancerous tumors. It said 3.1 percent of patients, or 23 people treated with the drug, developed tumors in clinical trials. That compared to two patients treated with a placebo during those studies, or 0.9 percent.
Despite those concerns, a majority of FDA's panelists backed approval for the drug, noting there are few treatments for patients with homozygous familial hypercholesterolemia that cannot be adequately treated by standard cholesterol drugs.
Jefferies analyst Eun Yang expects "very limited use of Kynamro if approved," due to the safety concerns brought up at the FDA meeting. In a note to clients, the analyst predicts peak U.S. sales of about $100 million.
Isis and Genzyme, a unit of the French drugmaker Sanofi, filed for European Union marketing approval of the drug in July 2011 and filed for U.S. approval in March 2012.
The FDA has set a target deadline of Jan. 29 to decide whether to approve sale of Kynamro in the U.S.