PharmAbcine received approval from the Australian Human Research Ethics Committees (HRECs) last Friday to conduct a phase 1a/b clinical trial of PMC-309.

PMC-309 is a VISTA-targeted immuno-oncology agent for patients with advanced or metastatic solid tumors.

According to PharmAbcine, PMC-309 is an IgG1 monoclonal antibody with specificity to bind only VISTA on immunosuppressive cells, with excellent binding across a range of PH conditions in the tumor microenvironment (TME).

The phase 1 study in Australia will evaluate the safety and efficacy of PMC-309 monotherapy and in combination with Keytruda (pembrolizumab). Merck (MSD) will provide Keytruda free of charge for this study. The trial will enroll up to 67 patients at four Australian institutions.

In phase 1a, PharmAbcine will identify the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of PMC-309 alone and combined with Keytruda in patients with advanced or metastatic solid tumors. The phase 1b study will evaluate the safety and tolerability of PMC-309 monotherapy and Keytruda in combination at the phase 2 recommended dose.

"The biggest hurdle in developing VISTA-targeted antibodies is the safety issue due to side effects caused by excessive immunity," said Dr. Lee Won-seop, head of PharmAbcine’s research center. "We hope to achieve a new leap forward in future immuno-oncology treatment options by confirming human safety in this clinical trial and securing the potential of PMC-309 alone and in combination with Keytruda."