U.S. regulators stamped an accelerated approval on Talon Therapeutics' ($TLON) Marqibo, sanctioning the new formulation of the generic anti-cancer drug vincristine for an uncommon form of leukemia based on efficacy data from a single clinical trial, the agency announced Thursday afternoon.
South San Francisco-based Talon has the green light from the agency to market the drug, which encases vincristine in a liposome, for patients with Philadelphia chromosome negative acute lymphoblastic leukemia whose disease has relapsed or for whom prior treatments have failed at least twice before. As Bloomberg reported, agency advisors expected that fewer than a mere 500 patients in the country would meet these requirements annually.
"Marqibo provides an additional option for Philadelphia chromosome negative acute lymphoblastic leukemia patients whose disease is unresponsive to available therapies," said Dr. Richard Pazdur, who is the head of the group responsible for hematology and cancer drug evaluations at the FDA.
Talon's shares were down 5.8% to 91 cents per share as of 2:17 p.m. ET on Thursday, giving the company a market value of about $20 million and indicating quite modest expectations for the company and its new drug. With the approval, the small outfit is obligated to cough up a $1 million payment to Tekmira Pharmaceuticals ($TKMR), a drug delivery specialist that licensed Marqibo to Talon in 2006, Tekmira said on Thursday.
Under the FDA's accelerated-approval plan, Talon has to complete further studies to flesh out the safety and efficacy profile of Marqibo. The agency granted a speedy nod for drug based on efficacy data from a 65-patient study in which 15.4% of those on the drug saw their cancer stop spreading or go into remission. For 10 patients, remission lasted for a median of 28 days, according to the FDA.
As the FDA's release notes, there are serious risks associated with Marqibo: Studies showed that three out of four patients on the drug suffered "serious adverse events," including low white blood cell counts, fever, respiratory distress and heart attacks.
- here's the FDA's release
- see Bloomberg's article
- and the Wall Street Journal's report
Editor's note: Updated with adverse event warnings for Marqibo.
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FDA OK's Talon's rare leukemia drug--kudos (though tempered) from some insider analysts.
Commentary yesterday after a story by @RyanMFierce