Gilead Sciences, Inc. (Nasdaq: GILD) today announced results of a Phase 2 study (Study 101-09) evaluating idelalisib, an investigational oral inhibitor of PI3K delta, for the treatment of patients with indolent non-Hodgkin’s lymphoma (iNHL) that is refractory (non-responsive) to rituximab and to alkylating-agent-containing chemotherapy. In this study, single-agent treatment with idelalisib achieved an overall response rate of 57 percent with a median duration of response of 12.5 months. The data were presented today during an oral session at the Annual Meeting of the American Society of Hematology (ASH) in New Orleans (Abstract #85). “It has been more than ten years since a treatment with a novel mechanism of action has been approved for indolent NHL, underscoring the medical need for new treatments for patients who are no longer responsive to currently available therapies,” said Ajay Gopal, MD, Associate Professor, University of Washington School of Medicine and Associate Member, Clinical Research Division, Fred Hutchinson Cancer Research Center in Seattle, Washington. “The overall response rate and durability of response observed in this study suggest that idelalisib may become a valuable new therapy for iNHL patients who have very limited treatment options.” Of the 71 patients who responded to therapy, seven (six percent) achieved a complete response, 63 (50 percent) had a partial response and one (one percent) had a minor response. Among patients who responded, the median duration of response was 12.5 months and the median time to response was 1.9 months. Median progression-free survival for all patients was 11.0 months and median overall survival was 20.3 months. Ninety percent of patients experienced shrinkage in lymph node size. The most common Grade ≥3 adverse event was diarrhea, which was reported in 16 patients (13 percent). Grade ≥3 transaminase elevations (a measure of liver function) were reported in 16 patients (13 percent). Of the 16 patients who had Grade ≥3 transaminase elevations, 14 were retreated with idelalisib and of those, 10 (71 percent) had no recurrence. Grade ≥3 neutropenia occurred in 34 patients (27 percent). Twenty-five patients (20 percent) discontinued therapy because of adverse events.