The US Food and Drug Administration (FDA) on 12 February 2014 expanded the approved use of ibrutinib (Imbruvica) for chronic lymphocytic leukaemia (CLL) patients who have received at least one previous therapy.
Ibrutinib is an oral Bruton’s tyrosine kinase inhibitor. In November 2013, the FDA granted ibrutinib accelerated approval to treat patients with mantle cell lymphoma, a rare and aggressive hematologic malignancy disease, if those patients received at least one prior therapy.
The latest approval provides an important new treatment option for CLL patients whose disease has progressed under previous treatment, according to Dr Richard Pazdur, 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 Imbruvica’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.”
Accelerated approval process
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 milligram orally administered dose of ibrutinib until the treatment reached unacceptable toxicity or the disease progressed.
Results showed an overall response rate of nearly 58%. At the time of the study, the duration of response ranged 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, diarrhoea, bruising, neutropenia, anaemia, upper respiratory tract infection, fatigue, musculoskeletal pain, rash, pyrexia, constipation, peripheral oedema, arthralgia, nausea, stomatitis, sinusitis and dizziness.
Imbruvica is manufactured by Sunnyvale, Calif.-based Pharmacyclics.