Parthenon Therapeutics has dosed first patient in a Phase I clinical trial of PRTH-101 for the treatment of patients with immune-excluded solid tumours.

Designed to assess the safety and tolerability of PRTH-101, the study will enrol up to 270 patients in the US with advanced or metastatic solid tumours.

Anti-tumour activity in select indications alone and in combination with anti-PD-1 inhibitors will be evaluated in the dose escalation, multi-centre, open-label and dose expansion study.

Preclinical models have demonstrated anti-tumor activity by targeting Discoidin Domain Receptor 1 (DDR1), a protein expressed on tumour cells that binds collagen.

Parthenon Therapeutics chief medical officer J Paul Eder said: “The initiation of a Phase I trial for PRTH-101 is an important step forward for cancer patients with DDR1-associated tumours, immune-excluded solid tumours, that have been shown to respond poorly to existing immuno-therapies.

“With no FDA-approved therapies that target DDR1- associated tumours, we believe that PRTH-101 could uniquely improve patient outcomes by breaking down the barrier that various types of tumours construct to protect them from immune attack.

“Parthenon continues to focus on an unmet need in cancer that hasn’t been successfully targeted therapeutically, namely, direct modulation of the tumour microenvironment to overcome immune exclusion.”

The trial will also evaluate DDR1 and pathway-related proteins as predictive biomarkers for patients whose tumours respond to treatment.

Based on the Phase I clinical results, the company will determine dosing regimens for its Phase II clinical programme.

DDR1 antagonist monoclonal antibody PRTH-101 loosens collagen fibres alignment and creates gaps in the tumour barrier, thereby allowing T-cells to enter and naturally attack the tumour.