Infinity Pharma: Retaspimycin HCl Phase 2 Study Fails To Meet Efficacy Endpoints

(RTTNews) - Infinity Pharmaceuticals Inc. (INFI) announced topline data from its Phase 2 study of retaspimycin hydrochloride or HCl, a potent and selective heat shock protein 90 (Hsp90) inhibitor, in patients with non-small cell lung cancer or NSCLC who had a history of smoking. In this double-blind, randomized, placebo-controlled study, retaspimycin HCl did not meet its pre-specified efficacy endpoints for demonstrating an improvement in overall survival in the total patient population or in patients with squamous cell carcinoma.

In addition, the combination did not show a treatment benefit in patient populations defined by pre-specified biomarkers, including KRAS, p53 and plasma levels of Hsp90-alpha.

In the study, the safety profile of retaspimycin HCl plus docetaxel was comparable to docetaxel and placebo.

The company said it expects to present the final data in a peer-reviewed setting after all analyses are complete. The company noted that it will not initiate any new trials with retaspimycin HCl.

According to the company, The Phase 2, randomized, placebo-controlled study evaluated the efficacy and safety of retaspimycin HCl plus docetaxel compared to placebo plus docetaxel in 226 patients with second- or third-line NSCLC who were naïve to docetaxel treatment and had a smoking history. Patients received 450 mg/m2 retaspimycin HCl or placebo dosed weekly in combination with the standard dose of docetaxel dosed once every three weeks during a 21-day cycle. The co-primary efficacy endpoints were overall survival in the entire patient population and overall survival in patients with squamous cell carcinoma.

"We will now focus our clinical research and development effort on IPI-145, our lead PI3K-delta,gamma inhibitor, for which we have encouraging data in patients with life-threatening hematologic malignancies," said Julian Adams, president of research and development at Infinity.

The company also announced that it will complete enrollment of the final cohort of patients in its separate, exploratory study of retaspimycin HCl in combination with everolimus (an mTOR inhibitor) in NSCLC patients with a KRAS mutation by the end of 2013 to conclude its development of retaspimycin HCl.