Gilead Sciences, Inc. (Nasdaq: GILD) today announced interim results from a single-arm, open-label Phase 2 study (Study 101-09) evaluating idelalisib (formerly GS-1101), an investigational, targeted, 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. Previously, this has been a largely unstudied population for which there is significant unmet medical need for effective therapy. In the study, single-agent treatment with idelalisib achieved an overall response rate of 53.6 percent, with a median duration of response at this interim analysis of 11.9 months. Detailed study results will be presented this Thursday during an oral session at the 12 th International Conference on Malignant Lymphoma in Lugano, Switzerland (Abstract #064bis).
“Despite the progress achieved in recent years, most patients suffering from indolent non-Hodgkin’s lymphoma will progressively become resistant to currently available treatments. Therefore, there is a significant unmet medical need for novel therapies,” said Gilles A. Salles, MD, PhD, Professor of Medicine, Department of Hematology, Claude Bernard University, Lyon-Sud Hospital Center, Pierre-Benite, France. “These data suggest that idelalisib has the potential to provide durable disease control to this group of patients who have few if any remaining conventional treatment options.”
The overall response rate observed in the study was 53.6 percent (n=67; 95 percent CI: 44.5, 62.6) with five complete responses (four percent), 60 partial responses (48 percent), two minor responses and 46 patients with stable disease (36.8 percent). The overall response rate was highly consistent across all subgroups analyzed. Among patients who responded, the median duration of response was 11.9 months and the median time to response was 1.9 months (1.8, 3.7). Median progression-free survival for all patients was 11.4 months. Most patients (89 percent) experienced some shrinkage in lymph node size.
The most common Grade ≥3 adverse event was diarrhea (10 percent). Grade ≥3 transaminase elevations (measure of liver function) were reported via central laboratory testing in 13 percent of patients; Grade ≥3 neutropenia occurred in 26 percent of patients. Sixteen percent of patients discontinued due to adverse events. The study is ongoing.