Phase 3 Libtayo monotherapy trial halted early due to strong benefit in advanced non-small cell lung cancer

A Phase 3 study of Sanofi and Regeneron’s Libtayo (cemiplimab) as a monotherapy for advanced or metastatic non-small cell lung cancer (NSCLC) has been stopped early after showing strong overall survival benefit, it has emerged.

The study, the largest clinical trial for a PD-1 inhibitor as a first-line monotherapy in this indication according to Sanofi, was halted under recommendation of the Independent Data Monitoring Committee

In lung cancer patients in whom more than 50% of tumour cells expressed PD-L1, Libtayo was 32.4% more effective in reducing risk of death compared to chemotherapy; this was achieved even though a third of the trial participants had be a part of the study for six months or less. Participants whose disease progressed were allowed to transition from chemo to receive Libtayo.

NSCLC accounts for around 85% of all lung cancer cases, and between 25% and 30% of cases will have a <50% PD-L1 expression in the tumour cells.

“While demonstrating a survival benefit in first-line NSCLC has been challenging for immunotherapies, the one FDA-approved anti-PD-1 monotherapy has changed the therapeutic paradigm,” explained George D Yancopoulos, Chief Scientific Officer at Regeneron. “We are pleased with the results of this trial that demonstrate the survival benefit of Libtayo in these patients and hope it may become a potential alternative for physicians and patients.”

Sanofi confirmed that the pair aim to pursue regulatory approval for the drug in this indication later this year. Libtayo has already secured approval for the treatment of metastatic cutaneous squamous cell carcinoma (CSCC) or locally advanced CSCC in adult patients who are not eligible for curative surgery or radiation.

Matt Fellows