OncoSec Medical Incorporated announced data from the Phase 2 KEYNOTE-695 clinical trial. This global, open-label single-arm trial is evaluating TAVO™, OncoSec's proprietary IL-12 encoding plasmid delivered by intratumoral electroporation (TAVO™-EP), in combination with pembrolizumab in patients with unresectable or metastatic (Stage III/IV) melanoma who had progressed on immediate prior anti-PD-1 antibody therapy (pembrolizumab or nivolumab). The last patient started treatment in December 2020, and clinical database lock occurred in October 2022. The key secondary endpoint of KEYNOTE-695 was met. Investigator assessment of overall response rate (ORR) per RECIST v1.1, from 101 efficacy evaluable patients, with at least one post-baseline tumor assessment, showed a confirmed ORR of 18.8% (95% confidence interval: 11.7, 22.8), which exceeds the pre-specified clinically meaningful ORR of =17% (95% CI: 10.2, 25.8).
Three patients achieved a complete response (CR) and 16 patients had a partial response (PR). Of note, 2 patients with CR had discontinued treatment with immediate prior nivolumab/ipilimumab. The disease control rate (CR + PR + stable disease) was 40.6%. The investigator-assessed durable response rate of =24 weeks was 15.8%, the median duration of response had not been reached. The median overall survival was 22.7 months (95% CI: 14.4, 35.5) after a median follow-up period of 33.4 months. The trial enrolled and collected safety data on 105 patients who had received at least 12 weeks of anti-PD-1 treatment and had confirmed disease progression. The combination therapy was generally well tolerated with no Grade 4/5 treatment-related adverse events (TRAEs). Grade 3 TRAEs were observed in 4.8% of patients. Top-line results of the primary endpoint of the KEYNOTE-695 trial, ORR by blinded, independent central review (BICR) based on RECIST v1.1, are expected to be announced in the first quarter of 2023.