Gileads Idelalisib Significantly Reduces Rate of Disease Progression or Death in Phase 3 Chronic Lymphocytic Leukemia Study

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-- Study 116 Stopped for Positive Efficacy in October; Met Primary Endpoint of Progression-Free Survival and Secondary Endpoints of Overall Response, Lymph Node Response and Overall Survival --

-- Data to be Presented During Late-Breaking Abstracts Session at American Society of Hematology Annual Meeting --

FOSTER CITY, Calif.--(BUSINESS WIRE)--Nov. 18, 2013-- Gilead Sciences, Inc. (Nasdaq: GILD) today announced that the company’s Phase 3 study (Study 116) evaluating idelalisib in combination with rituximab in previously-treated chronic lymphocytic leukemia (CLL) patients who were not fit for chemotherapy was accepted for presentation during a late-breaking abstracts session at the Annual Meeting of the American Society of Hematology (ASH) in New Orleans (Abstract #LBA-6). Detailed results from the study will be presented at ASH on December 10, 2013.

CLL is a slow-growing cancer in which the bone marrow overproduces white blood cells, leaving less room in the blood and bone marrow for other types of blood cells. It is the most common leukemia in adults in the United States, occurring typically in older individuals, and it can lead to life-threatening complications, including serious infections and anemia. In 2013, there were an estimated 16,000 new CLL diagnoses in the United States and 4,500 deaths related to this cancer.

“Patients with relapsed CLL have limited treatment options and are often not able to tolerate chemotherapy,” said Richard R. Furman, MD, Richard A. Stratton Assistant Professor of Clinical Medicine, Division of Hematology/Oncology, Weill Cornell Medical Center / New York Presbyterian Hospital. “Based upon the results of this study demonstrating significant improvements in progression-free and overall survival, idelalisib represents an important addition to the armamentarium for patients living with this life-threatening disease.”

Study 116 was stopped early based on a pre-specified interim analysis performed by an external Data Monitoring Committee (DMC) showing a highly statistically significant effect on the primary endpoint of progression-free survival (PFS).

Safety was in line with previous observations, and was largely consistent with advanced disease patients receiving CD20 antibody therapy.

Additional details contained in the Study 116 abstract are available at www.hematology.org/2013abstracts.

These data in CLL support Gilead’s plans for regulatory filings for idelalisib in the United States and European Union. On September 11, 2013, Gilead submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for idelalisib for the treatment of refractory indolent non-Hodgkin’s lymphoma (iNHL). Following Gilead’s NDA submission for iNHL, FDA granted idelalisib a Breakthrough Therapy designation for CLL in relapsed patients based on results from Study 116. Gilead is now engaging in a dialogue with the FDA regarding a regulatory filing in CLL. Gilead filed for approval in iNHL and CLL with the European Medicines Agency (EMA) on October 28, 2013.

About Study 116

Study 116 was a randomized, double-blind, placebo-controlled, Phase 3 study evaluating the efficacy and safety of idelalisib in combination with rituximab. The study enrolled 220 adult patients at approximately 70 study sites in the United States and Europe. Eligible patients had previously treated recurrent CLL, with measurable lymphadenopathy that had progressed within 24 months since completion of prior therapy. The patients required treatment (based on IWCLL criteria) but were not fit to receive cytotoxic therapy. Patients were randomized to receive eight infusions of rituximab over 24 weeks plus either idelalisib (150 mg) or placebo taken orally twice daily continuously until disease progression or unacceptable toxicity. Patients from Study 116 randomized to idelalisib will continue receiving idelalisib and patients in the control arm (placebo plus rituximab) were eligible to receive open-label idelalisib therapy in an extension study.

About Idelalisib

Idelalisib is an investigational, highly selective oral inhibitor of phosphoinositide 3-kinase (PI3K) delta. PI3K delta signaling is critical for the activation, proliferation, survival and trafficking of B lymphocytes and is hyperactive in many B-cell malignancies. Idelalisib is being developed both as a single agent and in combination with approved and investigational therapies.

In addition to Study 116, the development program in CLL includes two ongoing Phase 3 studies of idelalisib in previously treated patients. Gilead’s clinical development program for idelalisib in iNHL includes a Phase 2 study in highly refractory patients (Study 101-09) and two Phase 3 studies of idelalisib in previously treated patients. Combination therapy with idelalisib and GS-9973, Gilead’s novel spleen tyrosine kinase (Syk) inhibitor, also is being evaluated in a Phase 2 trial of patients with relapsed or refractory CLL, iNHL and other lymphoid malignancies.

Additional information about clinical studies of idelalisib and Gilead’s other investigational cancer agents can be found at www.clinicaltrials.gov. Idelalisib and GS-9973 are investigational products and their safety and efficacy have not been established.

About Gilead Sciences

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North and South America, Europe and Asia Pacific.

Forward-Looking Statement

This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including the possibility of unfavorable results from clinical trials involving idelalisib, including in combination with GS-9973 or other product candidates. Gilead also faces risks related to its ability to file for U.S. regulatory approval of idelalisib for CLL in the currently anticipated timelines. Gilead also faces risks related to its ability to enroll patients in Phase 3 studies and may need to modify or delay these studies. In addition, FDA, EMA and other regulatory agencies may not approve idelalisib for the treatment of iNHL or CLL in the anticipated timelines or at all, and any marketing approval may have significant limitations on its use. As a result, idelalisib may never be successfully commercialized. Further, Gilead may make a strategic decision to discontinue development of idelalisib, as a single agent or in combination with other products if, for example, Gilead believes commercialization will be difficult relative to other opportunities in its pipeline. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in Gilead’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2013, as filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements.

For more information on Gilead Sciences, please visit the company’s website at www.gilead.com, follow Gilead on Twitter (@GileadSciences) or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.