FDA OKs Ibrutinib (Imbruvica) for Mantle Cell Lymphoma

November 13, 2013

The US Food and Drug Administration (FDA) today approved ibrutinib (Imbruvica, Pharmacyclics, Janssen Biotech), a "breakthrough" drug for mantle cell lymphoma (MCL) that has been hailed as a successor to traditional chemotherapy in treating hematological cancer.

Ibrutinib is indicated for patients with MCL who have undergone at least one other therapy for this rare and aggressive form of blood cancer. The drug inhibits an enzyme that the cancer needs to multiply and spread.

Earlier this year, the FDA designated ibrutinib as a "breakthrough therapy," putting it on a fast track for development and approval. For a drug to qualify for breakthrough status, preliminary evidence must suggest a substantial improvement over current therapies for patients with a serious or life-threatening disease on at least one clinically significant endpoint.

In June, a study published in the New England Journal of Medicine appeared to confirm the promise of ibrutinib. Of 111 patients with MCL who took the once-daily drug, 68% had their cancer shrink or disappear. Other drugs treating MCL have much lower response rates, one of the study authors told Medscape Medical News at the time. The research also showed that the longer patients stayed on ibrutinib, the more they responded to it.

An accompanying New England Journal of Medicine (NEJM) editorial stated that "the results with ibrutinib are a further advance in the ever-changing management of hematological cancers, which is shifting from a chemotherapy-based approach to treatments aimed at the underlying biological mechanisms of disease occurrence and progression."

The FDA based its approval of ibrutinib on the study published in NEJM. The agency noted that researchers have yet to establish that the drug represents an improvement in survival or disease-related symptoms.

Ibrutinib is the second breakthrough therapy to get greenlighted by the FDA. The first is obinutuzumab (Gazyva, Genentech), approved earlier this month for patients with previously untreated chronic lymphocytic leukemia. The drug must be used in combination with chlorambucil.

MCL accounts for about 6% of all non-Hodgkin lymphoma cases in the United States. Because of the cancer's rarity, the FDA also gave ibrutinib orphan-drug status, which gives manufacturers economic benefits that make commercializing a drug for a small number of patients more feasible.

The most common adverse events experienced by clinical-trial participants include thrombocytopenia, diarrhea, neutropenia, anemia, fatigue, and musculoskeletal pain.

More information on the FDA's approval of ibrutinib is available at the agency's Web site.


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