PharmAbcine has commenced subject dosing in the Phase Ia/b clinical trial of its therapy PMC-309, targeting advanced or metastatic solid tumours.

An Immunoglobulin G1 (IgG1) monoclonal antibody, PMC-309 operates by attaching to VISTA on immunosuppressive cells within the tumour microenvironment, potentially activating T cells and monocytes and promoting M1 macrophage proliferation.

The open-label study comprises two parts, Phase Ia and Phase Ib.

Phase Ia will assess the tolerability and safety of PMC-309 as a single agent and in combination with Merck's KEYTRUDA (pembrolizumab).

The aim is to establish the maximum tolerated dose and the recommended Phase II dose (RP2D).

Following this, the Phase Ib stage will evaluate the tolerability and safety of PMC-309 monotherapy and the combination regimen at the RP2D.

The clinical trial is being conducted across four centres in Australia, with an enrolment target of 67 subjects.

It is a critical step in advancing PMC-309, which is part of PharmAbcine's pipeline that includes olinvacimab and PMC-403, as well as the IND (investigational new drug) application-approved PMC-309.

PharmAbcine develops next-generation IgG-based therapies for the treatment of cancer, neovascular eye diseases and vascular-related ailments.

The lead candidate of the company, olinvacimab, is currently in a Phase II trial in Australia, along with pembrolizumab, to treat metastatic triple-negative breast cancer (mTNBC).

The Phase II study aims to validate the promising results from the Phase Ib trial, which showed a 50% objective response rate, a 67% disease control rate and a clean safety profile.

PMC-403, another new candidate from PharmAbcine, is a TIE2-activating antibody currently undergoing a Phase I trial for patients with neovascular age-related macular degeneration in Korea.

PharmAbcine is also developing PMC-005, an anti-EGFRviii IgG antibody that selectively targets cancer cells expressing EGFRviii.

PharmAbcine president and CEO Dr Jin-San Yoo said: “This clinical trial aims to assess the human safety of PMC-309 and explore the potential of both monotherapy and combination therapy with KEYTRUDA.

“We are committed to developing new therapeutic options for cancer patients facing high unmet needs, emphasising our dedication to advancing oncology treatments.”