Replimune has initiated a Phase I clinical trial of its investigational candidate, RP2, as a monotherapy or in combination with Opdivo for the treatment of advanced solid tumours.

Based on the company’s Immulytic platform, RP2 expresses a genetically encoded protein that is similar to the anti-CTLA-4 antibody, along with the GALV-GP-R- fusogenic protein and GM-CSF.

The drug candidate is intended to prevent the inhibition of immune responses triggered by CTLA-4.

In preclinical studies, RP2 showed improved efficacy alone and in combination with anti-PD1 therapy.

Replimune co-founder, president and CEO Robert Coffin said: “CTLA-4 inhibition is an established mechanism of action for cancer treatment, including proven synergy with anti-PD1 therapy.

“By combining the expression of anti-CTLA-4 with oncolytic tumour destruction and antigen release directly in the tumour and draining lymph nodes, we believe that the efficacy of CTLA-4 inhibition can be enhanced with RP2, while reducing toxicity as compared to systemic administration.”

The Phase I trial will evaluate the safety and tolerability of RP2 alone and in combination with Opdivo, an anti-PD1 therapy developed by Bristol-Myers Squibb (BMS).

It also aims to determine the optimal dose. The first patient for the trial has been enrolled.

Replimune partnered with BMS for the study. BMS provided a non-exclusive, non-transferable, royalty-free licence to Opdivo for use with RP2 and will also supply its drug free of charge.

Earlier this month, Replimune started patient enrolment in a Phase II trial of another Immulytic product candidate RP1 to treat cutaneous squamous cell carcinoma (CSCC).