OncoSec Announces Positive Clinical Data of the KEYNOTE-695 Trial Assessing TAVO-EP in Combination with Pembrolizumab (Keytruda®) in Patients with Advanced Melanoma Refractory to anti-PD-1 Treatment

PENNINGTON, N.J. and SAN DIEGO, Nov. 11, 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.

"Patients with PD-1 refractory melanoma have limited treatment options. Therefore, we are encouraged by the observed response to treatment with TAVO™-EP and pembrolizumab in this difficult to treat patient segment," said Robert Arch, Ph.D., Chief Executive Officer of OncoSec. "In addition to the ORR of 18.8% in the full trial population of KEYNOTE-695, we are intrigued by the observed 19.5% investigator-assessed ORR, including 2 CRs and 6 PRs, in a subset of 41 patients who had prior exposure to ipilimumab (anti-CTLA-4 antibody) in addition to anti-PD-1 therapy. The data of TAVO™-EP combination treatment in patients who had failed multiple checkpoint inhibitors is encouraging and speaks to the differentiation of our TAVO™-EP approach from checkpoint inhibitors and other immunotherapies. I want to thank all patients who participated in the trial and our team at OncoSec that remains focused on developing TAVO™-EP as a novel intratumoral treatment approach for cancer patients with unmet medical needs."

Adil Daud, MD, Professor; UCSF Helen Diller Family Comprehensive Cancer Center commented on the data: "Patients with unresectable advanced melanoma who have progressed on prior anti-PD-1 therapy are not expected to gain benefit from retreatment with anti-PD-1 therapy. Therefore, the KEYNOTE-695 data highlight the value of intratumoral IL-12 as treatment for patients with checkpoint inhibitor refractory melanoma. Importantly, TAVO™-EP in combination with pembrolizumab in this highly refractory patient population with no standard-of-care treatment options showed durable responses and good tolerability. These data suggest that TAVO™-EP combined anti-PD-1 antibodies could make a major difference for a group of patients with a high unmet medical need."

About OncoSec Medical Incorporated
OncoSec Medical Incorporated (the "Company," "OncoSec," "we" or "our") is a biotechnology company focused on developing intratumoral immunotherapies to stimulate the patient's immune system to target cancer cells and eradicate disease. OncoSec's lead immunotherapy investigational product candidate – TAVO™ (tavokinogene telseplasmid) – enables the intratumoral delivery of DNA-based interleukin-12 (IL-12), a naturally occurring protein with immune-stimulating functions. The therapeutic approach TAVO™-EP, which employs electroporation, is designed to produce a localized expression of IL-12 in the tumor microenvironment and, thereby, stimulate the immune system to target and attack tumors. OncoSec's clinical pipeline is utilizing TAVO™ as a potential treatment for multiple cancer indications either as a monotherapy or in combination with checkpoint inhibitors; with the latter potentially enabling OncoSec to address a great unmet medical need in oncology: anti-PD-1 non-responders. Results from completed clinical trials of TAVO™ have demonstrated a local immune response, and subsequently, a systemic effect as either a monotherapy or combination treatment approach along with a well-tolerated safety profile, warranting further development of TAVO™-EP. For more information, please visit www.oncosec.com.