The FDA approved idelalisib (Zydelig; Gilead Sciences) for the treatment of patients with relapsed chronic lymphocytic leukemia (CLL) to be used in combination with rituximab (Rituxan). Idelalisib is recommended for use in this patient population in those for whom rituximab alone would be considered inappropriate therapy because of potential comorbidities. The drug received a breakthrough therapy designation for CLL earlier this year.
“In less than a year, we have seen considerable progress in the availability of treatments for chronic lymphocytic leukemia,” said Dr Pazdur. “Zydelig’s approval to treat CLL reflects the promise of the breakthrough therapy designation program and represents the FDA’s commitment to working cooperatively with companies to expedite a drug’s development, review and approval.”
On the same day, the FDA granted idelalisib an accelerated approval for the treatment of patients with relapsed follicular B-cell non-Hodgkin lymphoma (FL), as well as relapsed small lymphocytic lymphoma (SLL). Idelalisib is intended to be used in patients who have received at least 2 previous systemic therapies.
Idelalisib’s safety and effectiveness for relapsed CLL were established in a clinical trial of 220 patients with this condition who were randomized to receive idelalisib plus rituximab or placebo plus rituximab. The trial was stopped after the first prespecified interim analysis point, which showed that the active combination resulted in a progression-free survival (PFS) of 10.7 months compared with approximately 5.5 months with rituximab plus placebo. Results from a second interim analysis continued to show a statistically significant improvement for the active combination.
The safety and effectiveness of idelalisib in the treatment of FL and relapsed SLL were established in a clinical trial with 123 patients with indolent non-Hodgkin lymphomas. All patients received idelalisib and were evaluated for objective response rate (ORR). Results showed a 54% ORR in patients with relapsed FL and a 58% ORR for patients with SLL.
Idelalisib carries a Boxed Warning regarding the risk of fatal and serious toxicities, including liver toxicity, colitis, pneumonitis, and intestinal perforation. The drug was also approved with a REMS (Risk Evaluation and Mitigation Strategy) program.
Common side effects with idelalisib include diarrhea, fever, fatigue, nausea, cough, pneumonia, abdominal pain, chills, and rash. Common laboratory abnormalities include neutropenia, hypertriglyceridemia, hyperglycemia, and elevated levels of liver enzymes. (July 23, 2014)
