The FDA accelerated the approval of vincristine sulfate liposome injection (Marqibo; Talon Therapeutics) for the treatment of patients with Philadelphia chromosome–negative acute lymphoblastic leukemia (ALL), a rare type of leukemia, with a second or greater relapse after treatment with ≥2 antileukemia therapies. The drug is designated as an orphan product.
“Marqibo’s approval demonstrates the FDA’s commitment to the development and approval of drugs that address serious, unmet medical needs,” said Dr Pazdur. Some 1440 patients with ALL are estimated to die from this disease in 2012.
Marqibo contains vincristine, a common anticancer drug, encased within a liposome, which is a drug-delivery vehicle composed of material similar to cell membranes. Marqibo is injected once weekly by a healthcare professional.
The FDA approval of vincristine sulfate liposome was based on 1 clinical trial evaluating effectiveness and 2 studies evaluating safety. The safety trial included 65 patients who were in second relapse or greater; of these, 10 showed complete remission or complete remission with an incomplete blood count recovery with the active drug. The median duration of remission with vincristine sulfate liposome was 28 days, and the median time to a first event—including relapse, death, or next therapy—was 56 days.
The 2 safety trials were single-arm studies of 83 patients who received vincristine sulfate liposome. Of these, 28% of the patients discontinued the drug because of AEs, including peripheral neuropathy and tumor lysis syndrome. Serious AEs, such as low white blood–cell counts with fever, low blood pressure, respiratory distress, and cardiac arrest, were reported in 76% of the patients. The most common AEs during the trials were constipation, nausea, low blood-cell counts, fever, nerve damage, fatigue, diarrhea, decreased appetite, and insomnia.
Vincristine sulfate liposome carries a Boxed Warning that it must be administered intravenously, because this drug is deadly if it is administered in other ways (eg, into the spinal fluid). The warnings also state that the dosing recommendations for vincristine sulfate liposome are different from those for vincristine sulfate alone. To avoid overdose, it is important to verify the drug’s name and its dose before administration. The label lists special requirements for preparation of the drug. (August 9, 2012)
