Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today provided an update on the ongoing Phase 3 development program evaluating Libtayo® (cemiplimab), a PD-1 inhibitor, as monotherapy and combination therapy in first-line patients with advanced non-small cell lung cancer (NSCLC). Regeneron is currently recruiting patients in two Phase 3 trials in first-line NSCLC.

The first trial, an open-label randomized trial that compares Libtayo monotherapy to standard-of-care platinum-based chemotherapy in patients with high PD-L1 expression (tumor proportion score [TPS] >50%):

• The trial has enrolled 90% of the 700 planned patients and is expected to be fully enrolled by year's end.
• The independent data monitoring committee recently conducted an interim analysis for overall survival (OS) based on approximately 34% of anticipated events and recommended the trial should continue as planned. The next event-driven interim analysis for OS is anticipated in 2020.
• In the first 361 randomized patients (minimum 6 months of follow-up), the confirmed objective response rate (ORR), as determined by investigators, is currently 42% for Libtayo patients and 22% for patients treated with chemotherapy.

The second trial, which consists of two parts, evaluates Libtayo in combination with platinum-based chemotherapy:

• Part 1 is fully enrolled (n=323), and evaluates patients with PD-L1 expression of <50% in three treatment groups: chemotherapy, chemotherapy with Libtayo, and chemotherapy in combination with Libtayo and ipilimumab.
• Part 2, a randomized, double-blind, placebo-controlled Phase 3 trial (n=450), has enrolled approximately 20% of patients, and is expected to complete enrollment in the second half of 2020. The trial evaluates patients with all PD-L1 expression levels in two treatment groups: chemotherapy alone or chemotherapy in combination with Libtayo.

Libtayo is being jointly developed by Regeneron and Sanofi under a global collaboration agreement. Libtayo is a PD-1 inhibitor that was invented by Regeneron using the company's proprietary VelocImmune® technology, which uses a genetically-humanized mouse to produce optimized fully-human antibodies.