The U.S. Food and Drug Administration has approved Imbruvica (ibrutinib) to treat patients with mantle cell lymphoma (MCL) who have received at least one priory therapy. The drug blocks Bruton's tyrosine kinase (BTK), which has been shown to inhibit malignant B-cell survival.
“Imbruvica's approval demonstrates the FDA's commitment to making treatments available to patients with rare diseases,” Richard Pazdur, MD, Director of the FDA's Office of Hematology and Oncology Products, said in a news release. “The agency worked cooperatively with the companies to expedite the drug's development, review, and approval, reflecting the promise of the Breakthrough Therapy Designation program.”
Imbruvica is the second drug with that designation to be approved by the agency, and was also approved under the agency's accelerated approval program. The Food and Drug Administration Safety and Innovation Act, passed in July 2012, gave the FDA the ability to designate a drug a breakthrough therapy at the request of the sponsor if preliminary clinical evidence indicates the drug may offer a substantial improvement over available therapies for patients with serious or life-threatening diseases.
The accelerated approval program allows the FDA 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. The program provides earlier patient access to promising new drugs while the company conducts confirmatory clinical trials.
Additionally, Imbruvica was granted priority review and Orphan Product designation because the drug demonstrated the potential to be a significant improvement in safety or effectiveness in the treatment of a serious condition and is intended to treat a rare disease, respectively.
The drug's accelerated approval was based on a Phase II trial of 111 patients with MCL who had received at least one prior therapy who were given Imbruvica daily until disease progressed or side effects became intolerable. Nearly 66 percent of the patients' tumors shrank or disappeared after treatment. Improvement in survival or disease-related symptoms has not been established.
The most common side effects in patients receiving the drug were 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.
Imbruvica is the third drug approved for MCL, following Velcade (2006) and Revlimid (OT 7/10/13). The drug was jointly developed and is jointly being marketed by Janssen Biotech, Inc. and Pharmacyclics, Inc.