Imbruvica wins FDA OK for rare blood cancer
WASHINGTON -- The FDA approved ibrutinib (Imbruvica) on Wednesday for treatment of patients with mantle cell lymphoma (MCL), a rare and aggressive type of blood cancer.
The drug, which is intended for patients who have received at least one prior therapy for MCL, works by inhibiting the enzyme needed by the cancer to multiply and spread.
MCL represents about 6% of all non-Hodgkin lymphoma cases in the U.S. By the time MCL is diagnosed, it usually has already spread to the lymph nodes, bone marrow, and other organs.
The FDA's approval is based on a study of 111 patients who were given one ibrutinib capsule daily until their disease progressed or side effects became intolerable. Overall, the cancer got smaller or disappeared in about 66% of patients after treatment.
That was enough to move the drug quickly through the FDA's accelerated approval program, which allows drugs for serious conditions that fill an unmet medical need to be approved based on a surrogate or an intermediate clinical endpoint -- in this case, the regression of the cancer.
A requirement of the accelerated approval program, however, is that the drug's manufacturers -- Pharmacyclics and Janssen Biotech -- must now conduct studies to confirm that tumor shrinkage actually predicts that patients will live longer.
Side effects of the drug include thrombocytopenia, diarrhea, neutropenia, anemia, fatigue, musculoskeletal pain, edema, upper respiratory infection, nausea, bruising, shortness of breath, constipation, rash, abdominal pain, vomiting, and decreased appetite.
Other clinically significant side effects include bleeding, infections, kidney problems, and the development of other types of cancers.
On June 5, the FDA approved lenalidomide (Revlimid) for patients with MCL on standard therapy who relapse or progress. The only other drug approved for MCL is bortezomib (Velcade), which got the nod in 2006.
A randomized trial reported last year found that induction chemotherapy based on rituximab (Rituxan), followed by rituximab maintenance, was effective for older patients with MCL. The researchers of that trial noted that therapy for older MCL patients is limited because, unlike with younger patients, it's usually not possible to administer high dose cytarabine, followed by autologous stem-cell transplantation -- the first-line therapy.
Source: MedPage Today: http://www.medpagetoday.com/Washington-Watch/FDAGeneral/42889