Researchers at OncoSec Medical Incorporated revealed that the combination of the interleukin-12 encoding plasmid tavokinogene telseplasmid and intravenous pembrolizumab for the treatment of patients with unresectable or metastatic stage III or IV melanoma who did not respond to previous therapy was found to be ineffective at achieving the primary endpoint of a clinically meaningful 17% overall response rate in the phase II KEYNOTE-695 trial, according to an article published in Dermatology Times. In the new study, the researchers administered tavokinogene telseplasmid to 98 patients on the first, fifth, and eighth days of every 6-week cycle and 200 mg of intravenous pembrolizumab on the first day of every 30-week cycle. After a follow-up of 2 years, the researchers found that patients who received the combination treatment demonstrated an overall response rate of 10.2% (95% confidence interval = 5.00%–17.97%) and a disease control rate of 35.7%—with 4, 6, and 25 patients achieving complete response, partial response, and stable disease, respectively. An additional 8.2% (n = 8) of patients experienced a durable response of 2 years. “It is disappointing that [the findings] did not confirm the previously reported [preliminary] results. However, we remain optimistic that the observed long duration of response and [overall survival] of 22.7 months … provide rationale for further development of [tavokinogene telseplasmid] in combination with anti–PD-1 therapy,” concluded Robert Arch, PhD, Chief Executive Officer of OncoSec Medical Incorporated. The researchers plan to continue evaluating the safety and efficacy of tavokinogene telseplasmid in combination with nivolumab in a separate phase II trial for patients with melanoma—which has already demonstrated positive preliminary results.