Gilead's Zydelig® Combined with Bendamustine and Rituximab Shows Superior Efficacy to Bendamustine/Rituximab in Phase 3 Study of Patients with Relapsed Chronic Lymphocytic Leukemia

Following the recommendation by an independent Data Monitoring Committee (DMC), Gilead Sciences, Inc.

today announced that its Phase 3 Study 115 evaluating Zydelig® (idelalisib) added to standard therapy in previously-treated chronic lymphocytic leukemia (CLL) patients will be unblinded early. The DMC recommendation is based upon a predefined interim analysis indicating a statistically significant benefit in efficacy for progression-free survival (PFS) and overall survival (OS) in patients receiving Zydelig plus bendamustine and rituximab, compared to those receiving only bendamustine and rituximab. The safety profile of Zydelig was consistent with prior studies. Detailed results from this study will be presented during a late-breaking abstracts session (#LBA-5) at the Annual Meeting of the American Society of Hematology (ASH) in Orlando, Florida taking place December 5-8. Zydelig is approved in the United States in combination with rituximab for patients with relapsed CLL for whom rituximab alone would be considered appropriate therapy due to comorbidities. "The clinical benefit observed in this Phase 3 study adds to the body of evidence demonstrating the potential of Zydelig-containing treatment regimens for patients with previously treated CLL," said Norbert W. Bischofberger, PhD, Gilead's Executive Vice President, Research and Development and Chief Scientific Officer. "We look forward to sharing the detailed scientific data with the hematology community at the upcoming ASH meeting." Study 115 is a randomized, double-blind, placebo-controlled, Phase 3 study evaluating the efficacy and safety of Zydelig in combination with bendamustine and rituximab among 416 adult patients with previously treated CLL. Eligible patients were randomized (1:1) to receive six cycles of bendamustine and rituximab over 24 weeks combined with either Zydelig 150 mg or placebo taken orally twice daily continuously until disease progression or unacceptable toxicity. The primary endpoint is PFS. Additional details contained in the Study 115 abstract are available at https://ash.confex.com/ash/2015/webprogram/start.html. Based on these results, Gilead plans to submit supplemental regulatory filings in the U.S. and Europe early next year. The use of Zydelig in combination with bendamustine/rituximab is investigational and the safety and efficacy of this combination has not been established.