Infinity Pharmaceuticals, Inc. announced that ASPIRA, a Phase 2 study of duvelisib, an oral inhibitor of phosphoinositide-3-kinase (PI3K)-delta and PI3K-gamma, with background methotrexate in patients with moderate-to-severe rheumatoid arthritis (RA) did not meet its primary endpoint. The primary endpoint was the ACR20 response rate at 12 weeks, which is defined as the proportion of patients who achieve at least a 20% improvement in American College of Rheumatology (ACR) response criteria after 12 weeks of study treatment. Infinity will not proceed with any further clinical development of its PI3K inhibitors in rheumatoid arthritis.

Infinity is continuing to focus on advancing duvelisib for the treatment of blood cancers and is conducting registration-focused studies of duvelisib in indolent non-Hodgkin lymphoma and chronic lymphocytic leukemia, forms of blood cancer for which there are no cures. This Phase 2, double-blind, randomized, placebo-controlled study was designed to evaluate the efficacy, safety and pharmacokinetics of duvelisib dosed at either 0.5 mg, 1.0 mg or 5.0 mg twice daily (BID) for 12 weeks with background methotrexate compared to treatment with placebo plus methotrexate. The study evaluated 322 adults with active moderate-to-severe RA receiving a stable dose of methotrexate.

The primary efficacy endpoint of the study was the ACR20 response rate at week 12. An effect of duvelisib compared to placebo was not observed on the primary endpoint at any of the three dose levels tested. The majority of side effects observed were Grade 1-2, reversible or clinically manageable, and no new safety signals associated with duvelisib therapy were identified.

Infinity will continue to analyze the study results and expects to submit the data for publication in a peer-reviewed forum.