PharmAbcine Inc. announced that PMC-309, VISTA-targeting immuno-oncology program, received safety approval for the first dose cohort (0.2mg/kg) in Phase 1a/b clinical trial for patients with advanced or metastatic solid tumors in Australia. The second dose cohort (0.5mg/kg) is currently ongoing. The first dose cohort (0.2mg/kg) of PMC-309 was initially administered in January 2024 and received safety approval in April 2024.

Currently, the second dose cohort (0.5mg/kg) has been administered to two patients, with the third patient scheduled to receive treatment soon. PMC-309 is an IgG1 monoclonal antibody specifically binding to VISTA on immunosuppressive cells, demonstrating excellent binding affinity at various pH conditions within the tumor microenvironment (TME). By inhibiting VISTA, PMC-309 offers a differentiated mechanism of action, contributing to anti-cancer effects through the activation of T cells, monocytes, and the proliferation of M1 macrophages.

This open-label Phase 1a/b clinical trial involves a total of 67 patients and comprises two phases: Phase 1a and Phase 1b. Phase 1a includes PMC-309 monotherapy and combination therapy with KEYTRUDA® (pembrolizumab) to determine the maximum tolerated dose (MTD) and the recommended Phase 2 dose (RP2D). Phase 1b will evaluate the safety and tolerability of PMC-309 monotherapy and combination therapy with KEYTRUDA® at the RP2D.

The clinical trial is being conducted at four institutions in Australia.