FDA Panel Backs Drug for Rare Type of Leukemia
WASHINGTON -- An FDA advisory committee has tepidly endorsed vincristine sulfate liposomal injection (Marqibo) to treat adults with a rare type of acute lymphoblastic leukemia.
The FDA's Oncologic Drugs Advisory Committee voted 7-4, with two panelists abstaining, that the benefits outweigh the risks for vincristine sulfate liposomal injection for the treatment of adult patients with Philadelphia chromosome negative (Ph-) acute lymphoblastic leukemia (ALL) in second or greater relapse or who have failed at least two prior treatments with other anti-leukemia drugs.
Adult ALL is one of the rarest types of cancer -- there are about 2,000 new cases of adult ALL diagnosed each year in the U.S.
Although panelists were only lukewarm about data presented by Talon Pharmaceuticals, the maker of vincristine sulfate liposomal injection, most felt having the option for patients was better than not having the option.
If the FDA agrees with the panel's decision, it would then grant the drug an accelerated approval, which would allow it to come to market even as the company was performing another study to prove the drug really works.
Talon is seeking approval for vincristine sulfate liposomal injection, or VSLI for short, as a monotherapy injectable form of the drug.
Giving the drug via injection means the patient doesn't have to spend time in the hospital receiving multi-agent chemotherapy.
On Wednesday morning, the panel reviewed Talon's phase II single-arm, open-label, dose-escalation trial of 65 Ph- ALL patients who had failed two or more previous anti-leukemia treatments.
The study's endpoint was rate of complete remission with or without complete blood count recovery (known as CRघ).
Ten of the 65 patients (15.4%) achieved complete remission (judged by an examination of bone marrow) that lasted for a median of 28 days.
Talon pointed to another endpoint in its briefing documents: Median overall survival in the entire population treated was 4.6 months, while those who achieved CRघ lived an average of 7.7 months.