Regeneron presents secondary endpoints for PD-1 inhibitor Libtayo regimen

Regeneron Pharmaceuticals announced the first presentation of key secondary endpoints for an investigational regimen of PD-1 inhibitor Libtayo as a neoadjuvant monotherapy in stage II to IV resectable cutaneous squamous cell carcinoma. The results from an international Phase 2 trial were presented in an oral session at the European Society for Medical Oncology Congress 2023 and concurrently published in The Lancet Oncology. The multicenter, single-arm Phase 2 trial included two parts. In Part 1, patients received Libtayo 350 mg every three weeks for up to four doses, followed by curative-intent surgery. Per the primary analysis presented at ESMO 2022 and published in the New England Journal of Medicine, there was a 63.3% combined pathologic response rate. This included a 50.6% pathologic complete response rate and a 12.7% major pathologic response rate. In Part 2, the post-surgical part of the trial, patients who completed curative intent surgery, received an investigator’s choice of Libtayo, radiation or observation. The presentation at this year’s ESMO shared secondary survival endpoints among all 79 patients in the trial, continuing to demonstrate encouraging outcomes at one-year, including: 89% event-free survival rate at one year, per Kaplan-Meier estimates, with the median not reached. No disease recurrence among patients who achieved a pCR. Among those achieving an MPR, 9 of 10 remained disease-free at one year. 92% overall survival rate at one year, per Kaplan-Meier estimates, with the median not reached. Among all patients, adverse events of any grade occurred in 89% of patients, with 19% being greater than or equal tograde 3, and one death due to worsening congestive heart failure considered possibly related to treatment. Among those who received adjuvant Libtayo in Part 2 of the trial, there were two grade 3 serious AEs including worsening cardiomyopathy and hypophysitis and no deaths considered related to treatment. A separate ongoing global Phase 3 trial is investigating Libtayo in the adjuvant CSCC setting for patients at heightened risk for recurrence after surgery and radiotherapy. The potential use of Libtayo described above is investigational, and its safety and efficacy has not been evaluated by any regulatory authority for this indication.