Morphogenesis, Inc. and CohBar, Inc. announced positive initial results from an exploratory analysis of anti-tumor responses to rechallenge with an ICI following protocol directed IFx-Hu2.0 therapy among patients with advanced MCC or cSCC who exhibited primary resistance to ICIs. The abstract titled, “Phase 1b trial of IFx-Hu2.0, a novel personalized cancer vaccine, in checkpoint inhibitor resistant Merkel cell carcinoma and cutaneous squamous cell carcinoma,” was presented by Andrew Brohl, MD, H. Lee Moffitt Cancer Center and Research Institute in a poster presentation as part of the Melanoma/Skin Cancers – Advanced/Metastatic Diseases session held at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place June 2-6, 2023 in Chicago, IL. IFx-Hu2.0 is Morphogenesis' lead personalized cancer vaccine candidate that is designed to overcome primary resistance to checkpoint inhibitors.

In a Phase 1 study in advanced melanoma, biomarker analyses demonstrated robust immune priming effects of IFx administration. The ongoing Phase 1b study evaluates IFx-Hu2.0 in a two-stage study design to assess safety and to examine the effects of repeated weekly dosing up to 3 weeks on the magnitude of the ensuing systemic immune response to determine the optimal dose and schedule for the company's planned Phase 2/3 registration directed trial. As reported at ASCO, following completion of protocol directed therapy, 5 patients with advanced MCC and 2 patients with cSCC who, prior to study entry, failed anti-PD(L)1 therapy were re-treated with anti-PD(L)1 monotherapy: pembrolizumab (3) or avelumab (2) in MCC and cemiplimab (2) in cSCC.

Four of 5 (80%) patients with advanced MCC and 1 of 2 (50%) patients with cSCC, or 5 of 7 total (71%), experienced objective anti-tumor responses to ICI rechallenge in this setting, with duration of response ongoing in 4 patients (7+, 8+, 9+, 20+ months) and one response lasting 23 months. All 4 patients with advanced MCC with post-protocol response to anti-PD(L1) therapy had previously experienced progression to this same drug class prior to treatment on protocol. Based on the positive preliminary results seen to-date, an additional 11 patients are planned for enrollment in the expansion stage of the Phase 1b study using the weekly x 3 dosing schedule.

Additional exploratory/biomarker analyses are planned.