Orphan drug approved under agency’s accelerated approval program
Silver Spring, Maryland–(ENEWSPF)–August 9, 2012. The U.S. Food and Drug Administration today approved Marqibo (vincristine sulfate liposome injection) to treat adults with a rare type of leukemia called Philadelphia chromosome negative (Ph-) acute lymphoblastic leukemia (ALL).
ALL is a rapidly progressing form of blood and bone marrow cancer that is more commonly diagnosed in children than adults. According to the National Cancer Institute, an estimated 6,050 men and women will be diagnosed with ALL and 1,440 will die from the disease this year.
Marqibo is approved for patients whose leukemia has returned (relapsed) two or more times, or whose leukemia has progressed following two or more regimens of anti-leukemia therapy. Marqibo contains vincristine, a commonly used anti-cancer drug, encased within a liposome, a drug delivery vehicle composed of material similar to that of cell membranes. It is an injection administered once a week by a health care professional.
“Marqibo’s approval demonstrates the FDA’s commitment to the development and approval of drugs that address serious, unmet medical needs,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Marqibo provides an additional option for Philadelphia chromosome negative acute lymphoblastic leukemia patients whose disease is unresponsive to available therapies.”
Marqibo is approved under the FDA’s accelerated approval program, which allows the agency to approve a drug to treat a serious disease based on clinical data showing that the drug has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. This program provides earlier patient access to promising new drugs while the company conducts additional clinical studies to confirm the drug’s clinical benefit and safe use. Marqibo also received orphan-product designation by the FDA because it is intended to treat a rare disease or condition.
The drug’s effectiveness was evaluated in a single clinical trial in adult patients whose leukemia had relapsed at least two times despite standard treatments, and who had at least one previous treatment response lasting at least 90 days. The study objective was to determine the response rate to Marqibo, as either a complete remission (CR) or a complete remission with incomplete blood count recovery (CRi). Of 65 patients enrolled, 10 patients, or 15.4 percent, responded with either a CR or CRi. In the 10 patients achieving CR or CRi, the median duration of documented remission was 28 days. The median time to the first event of relapse, death, or next therapy was 56 days.
The safety of Marqibo was evaluated in two single-arm trials of 83 patients who received the clinical treatment regimen. Serious adverse events such as low white blood cell counts with fever, low blood pressure, respiratory distress and cardiac arrest occurred in 76 percent of the patients studied. The most common side effects observed during clinical studies include constipation, nausea, low blood cell counts, fever, nerve damage, fatigue, diarrhea, decreased appetite, and insomnia.
Prescribing information for Marqibo will carry a Boxed Warning alerting patients and health care professionals that the drug must be administered only through a vein (intravenously) because it is deadly if administered in other ways, such as into the spinal fluid. The Boxed Warning also states that Marqibo has different dosage recommendations than vincristine sulfate injection alone. To avoid overdose, it is important for health care professionals to verify the drug name and the dose before administration. Special requirements for preparation of the drug are detailed in the label.
Marqibo is marketed by Talon Therapeutics Inc., based in South San Francisco, Calif.
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