Regeneron's REGN5678 Shows Encouraging Anti-tumor Activity When Combined With Libtayo

(RTTNews) - Regeneron Pharmaceuticals, Inc. (REGN) on Wednesday reported encouraging initial data from Phase 1/2 study of REGN5678 in combinations with the company's Libtayo in advanced metastatic castration-resistant prostate cancer (mCRPC).

The Phase 1/2 study is currently enrolling patients with advanced mCRPC whose tumors have previously progressed on multiple anti-androgen therapies, with a majority also having received prior chemotherapy.

In the Phase 1 dose-escalation portion of the Phase 1/2 study, patients with advanced mCRPC were initiated with weekly doses of REGN5678, for three weeks, which then continued in combination with standard dose of anti-PD-1 agent Libtayo.

Preliminary data from the dose-escalation portion of the trial, across 8 dose level cohorts and a total of 33 patients, showed dose-dependent anti-tumor activity per centrally collected prostate-specific antigen (PSA) values.

PSA is a protein produced by the prostate gland and is commonly used as a biomarker to diagnose and follow prostate cancer.

The lack of anti-tumor activity among these patients was consistent with the approximate 6% response rate reported in other trials with anti-PD1 monotherapy, the company said.