Talon Leukemia Treatment Wins Backing of FDA Advisory Panel

Talon Therapeutics Inc., a biotechnology company with no marketed products, won the backing of a U.S. advisory panel for accelerated approval of its blood-cancer treatment.

The advisers voted 7-4 that the benefits of the anti-leukemia therapy outweigh its risks. The Food and Drug Administration is considering Marqibo, the San Mateo, California-based company’s lead product candidate, based on the second of three phases of clinical trials typically required for approval.

Talon, which has no annual revenue, would have to complete the final trials and prove the drug’s benefit if the FDA clears the treatment. The agency is due to decide by May 13. The therapy would treat adults with a form of acute lymphoblastic leukemia, a fast-growing cancer of the white blood cells.

“I felt that it was better to give the benefit of the doubt to this drug given this very rare and unfortunate setting,” said Wyndham Wilson, the panel chairman and chief of the National Cancer Institute’s Lymphoma Therapeutics Section in Bethesda Maryland.

Talon rose 9.5 percent to 81 cents at the close of New York trading.

4,000 Cases

About 4,000 new cases of acute lymphoblastic leukemia are diagnosed each year and mostly in children, according to the National Marrow Donor Program. One-third of the cases are in adults.

Marqibo would treat adult patients with the type of acute lymphoblastic leukemia that is negative for an abnormality known as the Philadelphia chromosome and who have had multiple relapses or a disease that has progressed after taking two or more therapies.

All 65 patients in the study took Marqibo and stopped the therapy because of side effects including nerve damage and metabolic disorders, according to an FDA staff report released March 19. The trial’s ability to assess survival is “difficult to interpret” the FDA staff said because it didn’t compare the treatment to a placebo, meaning the result could be “heavily influenced by other nondrug factors.”

The FDA staff recommended a final-phase trial to confirm the therapy’s benefit. The trial would measure survival rates of almost 350 patients using Marqibo as a substitute for the standard cancer drug vincristine. Talon’s product is an encapsulated form of vincristine and is designed to provide prolonged circulation of the chemotherapy in the blood and accumulation at the tumor site, the company said.

Talon, formerly Hana Biosciences Inc., licensed Marqibo in 2006 from Inex Pharmaceuticals Corp., which broke off its pharmaceutical assets to become Burnaby, British Columbia-based Tekmira Pharmaceuticals Corp. The FDA rejected Marqibo for use in non-Hodgkin’s lymphoma in 2005. The agency wanted more studies before it would grant conditional approval.