FDA Approves Idelalisib for Three Types of Blood Cancers


Key Points

  • The FDA has approved idelalisib in combination with rituximab for patients with relapsed chronic lymphocytic leukemia.
  • Idelalisib has also received accelerated approval for patients with relapsed follicular B-cell non-Hodgkin lymphoma and relapsed small lymphocytic lymphoma who have received at least two prior therapies.

The U.S. Food and Drug Administration (FDA) has approved idelalisib (Zydelig) for the treatment of patients with three types of blood cancers.

Idelalisib is being granted traditional approval to treat patients with relapsed chronic lymphocytic leukemia (CLL). Used in combination with rituximab (Rituxan), idelalisib is to be used in patients for whom rituximab alone would be considered appropriate therapy due to other existing comorbidities. Idelalisib is the fifth new drug with Breakthrough Therapy designation to be approved by the FDA and the third drug with this designation approved to treat CLL.

The FDA is also granting idelalisib accelerated approval to treat patients with relapsed follicular B-cell non-Hodgkin lymphoma and relapsed small lymphocytic lymphoma. Idelalisib is intended to be used in patients who have received at least two prior systemic therapies.

Progress in CLL

“In less than a year, we have seen considerable progress in the availability of treatments for chronic lymphocytic leukemia,” 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 approved obinutuzumab (Gazyva) in November 2013, ibrutinib (Imbruvica) in February 2014, and a new use for ofatumumab (Arzerra) in April 2014 to treat CLL. Both obinutuzumab and ofatumumab also received Breakthrough Therapy designation for this indication. Like the other two drugs, idelalisib was also granted Orphan Drug designation because it is intended to treat a rare disease.

Idelalisb’s safety and effectiveness to treat relapsed CLL were established in a clinical trial of 220 participants who were randomly assigned to receive idelalisib and rituximab or placebo and rituximab. The trial was stopped for efficacy following the first prespecified interim analysis point, which showed participants treated with idelalisib and rituximab had a median progression-free survival of 10.7 months compared to about 5.5 months for participants treated with placebo and rituximab. Results from a second interim analysis continued to show a statistically significant improvement for idelalisib and rituximab over placebo and rituximab.

New Indications for Non-Hodgkin Lymphomas

Idelalisib’s safety and effectiveness to treat relapsed follicular lymphoma and relapsed small lymphocytic lymphoma were established in a clinical trial with 123 participants with indolent non-Hodgkin lymphomas. All participants were treated with idelalisib and were evaluated for objective response rate. Results showed 54% of participants with relapsed follicular lymphoma and 58% of participants with small lymphocytic lymphoma experienced complete or partial disappearance of their cancer.

The FDA is approving idelalisib to treat follicular lymphoma and small lymphocytic lymphoma under the agency’s accelerated approval program, which allows approval of a drug to treat a serious or life-threatening disease based on clinical data showing the drug has an effect on a surrogate endpoint reasonably likely to predict clinical benefit to patients. This program provides earlier patient access to promising new drugs while the company conducts confirmatory clinical trials.

Side Effects

Idelalisib carries a Boxed Warning alerting patients and health-care professionals of fatal and serious toxicities including liver toxicity, diarrhea and colitis, pneumonitis, and intestinal perforation that can occur in idelalisib-treated patients. Idelalisib is also being approved with a Risk Evaluation and Mitigation Strategy (REMS) comprised of a communication plan to ensure health-care providers who are likely to prescribe idelalisib are fully informed about these risks.

Common side effects include diarrhea, pyrexia, fatigue, nausea, cough, pneumonia, abdominal pain, chills, and rash. Common laboratory abnormalities include neutropenia, hypertriglyceridemia, hyperglycemia, and elevated levels of liver enzymes.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.