Regeneron, Sanofi Present Positive Study Results For PD-1 Antibody REGN2810

(RTTNews) - Regeneron Pharmaceuticals Inc. (REGN) and Sanofi announced positive preliminary results with investigational REGN2810, a checkpoint inhibitor targeting PD-1 (programmed death 1), in patients with advanced cutaneous squamous cell carcinoma or CSCC.

REGN2810 is also being investigated in EMPOWER-CSCC 1, an ongoing Phase 2 potentially pivotal, single-arm, open label clinical trial that is currently enrolling advanced CSCC patients.

Treatment with REGN2810 led to an investigator-assessed overall response rate (ORR) of 46.2 percent (12 of 26 patients, including 2 complete responses, 9 partial responses and 1 unconfirmed partial response) and a disease control rate (DCR) of 69.2 percent (18 of 26 patients, including 12 ORR and 6 stable disease). The median progression free survival and overall survival were not reached at the data cutoff date with a median follow up of 6.9 months (range: 1.1 to 13.8 months; ongoing). One patient experienced progressive disease during treatment with REGN2810 after the initial response, and two patients were not evaluable due to death, which was considered unrelated to REGN2810. Ten patients remain in response as of the data cutoff date (range: 8 to 40 weeks duration of response).

The most common treatment-related adverse event of any grade was fatigue (23.1 percent). All grade 3 or higher adverse events occurred once and included arthralgia (3.8 percent), maculopapular rash (3.8 percent), asthenia (3.8 percent), aspartate aminotransferase (AST) elevation (3.8 percent) and alanine aminotransferase (ALT) elevation (3.8 percent).

No apparent association between the objective response and level of PD-L1 (programmed death ligand 1) expression was found. PD-L1 expression by immunohistochemistry (22C3 clone, Dako) was performed in tumor cells for 21 expansion cohort patients, with 81 percent of patients (17 of 21) having greater than or equal to 1 percent positive PD-L1 expression. Additional correlative studies are in process.