The U.S. Food and Drug Administration (FDA) has expanded the approved use of ibrutinib (Imbruvica) for the treatment of patients with chronic lymphocytic leukemia (CLL) who have received at least one previous therapy. Ibrutinib, an oral Bruton’s tyrosine kinase inhibitor, was previously granted accelerated approval by the FDA for patients with mantle cell lymphoma who received at least one prior therapy.
“Today’s approval provides an important new treatment option for CLL patients whose cancer has progressed despite having undergone previous therapy,” said Richard Pazdur, MD, Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “The FDA completed its review of [ibrutinib’s] new indication under the agency’s accelerated approval process, which played a vital role in rapidly making this new therapy available to those who need it most.”
Under the agency’s accelerated approval process, the FDA may approve a drug based on a surrogate or intermediate endpoint that is reasonably likely to predict clinical benefit. Drugs receiving accelerated approval are usually subject to an agreement to conduct confirmatory trials verifying and describing clinical benefit. Ibrutinib for CLL also received 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 FDA’s accelerated approval of ibrutinib for CLL is based on a clinical study of 48 previously treated participants. On average, participants were diagnosed with CLL 6.7 years prior to the study and had received four previous therapies. All study participants received a 420 mg orally administered dose of ibrutinib until the treatment reached unacceptable toxicity or the disease progressed. Results showed an overall response rate of nearly 58%, with the duration of response ranging from 5.6 to 24.2 months. An improvement in survival or disease-related symptoms has not been established.
The most common side effects observed in the clinical study include thrombocytopenia, diarrhea, bruising, neutropenia, anemia, upper respiratory tract infection, fatigue, musculoskeletal pain, rash, pyrexia, constipation, peripheral edema, arthralgia, nausea, stomatitis, sinusitis, and dizziness. ■