FDA approves drug to treat 3 types of blood cancers

FDA approved idelalisib (Zydelig, Gilead Sciences) to treat patients with 3 types of blood cancers.

Zydelig has been approved to treat patients whose chronic lymphocytic leukemia (CLL) has returned (relapsed). Used in combination with rituximab (Rituxan, Genentech, a member of the Roche Group), Zydelig is to be used in patients for whom Rituxan alone would be considered appropriate therapy due to other existing medical conditions (comorbidities).

Zydelig 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.

Zydelig also has been granted accelerated approval to treat relapsed follicular B-cell non-Hodgkin lymphoma (FL) and relapsed small lymphocytic lymphoma (SLL), another type of non-Hodgkin lymphoma. Zydelig is meant for patients who have received at least 2 prior systemic therapies.

“The FDA approval of [Zydelig] for CLL offers an additional treatment option for individuals who are diagnosed with this form of cancer. There is the opportunity for positive treatment outcomes if all other agents have failed to produce a desired effect,” said FormularyWatch advisor Abimbola Farinde, PharmD, MS, who serves on the faculty at Columbia Southern University, Orange Beach, Ala.

FDA approved obinutuzumab (Gazyva, Genentech, a member of the Roche Group) in November 2013, ibrutinib (Imbruvica, Pharmacyclics and Janssen Biotech) in February 2014 and a new use for ofatumumab (Arzerra, GlaxoSmithKline) in April 2014 to treat CLL. Both Gazyva and Arzerra also received breakthrough therapy designation for this indication. Zydelig was also granted orphan product designation.

Zydelig’s approval to treat relapsed CLL was established in a clinical trial of 220 participants randomly assigned to receive Zydelig and Rituxan or placebo and Rituxan. The trial was stopped for efficacy following the first pre-specified interim analysis point, which showed participants treated with Zydelig and Rituxan had the possibility of living at least 10.7 months without their disease progressing (progression-free survival) compared to about 5.5 months for participants treated with placebo and Rituxan. Results from a second interim analysis continued to show a statistically significant improvement for Zydelig and Rituxan over placebo and Rituxan.

Zydelig’s approval to treat relapsed FL and relapsed SLL was established in a clinical trial with 123 participants with slow-growing (indolent) non-Hodgkin lymphomas. All participants were treated with Zydelig and were evaluated for complete or partial disappearance of their cancer after treatment (objective response rate, or ORR). Results showed 54% of participants with relapsed FL and 58% with SLL experienced ORR.

The FDA is approving Zydelig to treat FL and SLL under the agency’s accelerated approval program.

Zydelig has a Boxed Warning in its product label regarding the risks of fatal and serious toxicities: Hepatic, severe diarrhea, colitis, pneumonitis and intestinal perforation.

The most common adverse reactions (incidence ≥20%; all grades) in patients given Zydelig with or without rituximab are diarrhea, pyrexia, fatigue, nausea, cough, abdominal pain, chills and rash. The most common lab abnormalities (incidence ≥30%; all grades) in clinical studies were neutropenia, hypertriglyceridemia, hyperglycemia and ALT/AST elevations (indicators of liver function).