Oncotelic Therapeutics has received a Food and Drug Administration (FDA) clearance to commence the Phase II M201 clinical trial of OT-101 plus pembrolizumab in patients with malignant pleural mesothelioma (MPM ).

A TGF-β inhibitor, OT-101 is co-owned by Oncotelic with its joint venture partners Dragon and GMP Bio.

The company will commence the Phase II Investigator Initiated Study (IIS) in MPM patients in partnership with Merck, which will supply the anti-PD-1 inhibitor, pembrolizumab, for the trial.

The open-label, non-randomised, single-arm Simon’s two stage trial will enrol up to 63 MPM patients across various US centres. 

MPM patients who fail to attain or maintain response following checkpoint inhibition will be part of the trial.

Before commencing the efficacy analysis portion, a run-in dose-escalation phase of the trial will be carried out to analyse the safety and tolerability of various doses of OT-101 plus pembrolizumab.

This dose-escalation phase will also identify a recommended Phase II dose (RP2D) of four days of continuous intravenous infusion for every two weeks regimen. 

The initial stage of Simon’s two-stage design will include participants who received the RP2D in the dose-escalation phase. 

To determine if the combination treatment can offer improved tumour response (ORR) in MPM patients who fail to attain or maintain a response following anti-PD-1/PD-L1-based regimens will be the trial’s primary objective.

One of the trial’s secondary goals includes determining if treatment induced ORR could offer an improved duration of response (DOR), six-month and 12-month overall survival (OS) and progression-free survival (PFS) versus pembrolizumab as monotherapy.

The other secondary goal is to assess the safety and tolerability of OT-101 plus pembrolizumab in mesothelioma patients.

Oncotelic Therapeutics Translational Medicine chief clinical officer Dr Anthony Maida said: “This study encompasses a broad clinical strategy, which includes a robust and rigorous assessment of changes within the tumour microenvironment of various indications relative to pre and post therapy including the measurement of nearly 800 genes, spatial distribution of immune effector cells, expression of cytokines, phenotypic and functional changes, immunohistochemistry and deep sequencing in the hopes of better understanding the etiology and progression of malignancies and ultimately clinical benefit.”