Daiichi Sankyo has dosed the first patient in a first-in-human global Phase I trial to evaluate a Glycoprotein-A Repetitions Predominant (GARP) directed immuno-oncology therapy, DS-1055, in patients with advanced or metastatic solid tumours.

DS-1055 is a monoclonal antibody that can target GARP, a transmembrane protein seen on the surface of activated Tregs in the tumour microenvironment.

The therapy can potentially aid GARP positive Tregs to promote anti-tumour immunity.

At present, no GARP directed therapies have been approved for cancer treatment.

Daiichi Sankyo Global Oncology Development, Alpha Portfolio vice-president Arnaud Lesegretain said: “We are pleased to initiate clinical development to further evaluate the novel mechanism behind DS-1055, which was specifically designed to decrease the number of GARP expressing regulatory T cells and restore antitumor immune response.

“Evidence suggests that DS-1055 could serve as a new type of immune-based therapy for patients with various cancers, including those resistant or refractory to checkpoint inhibitors.”

The global, multi-centre, open-label dose escalation trial will analyse the safety, tolerability and preliminary efficacy of DS-1055 in adult patients with relapsed/refractory advanced or metastatic head and neck, gastric and esophageal cancers and other tumour types.

Those who have progressed on standard treatments, including checkpoint inhibitors, will be part of the trial.

Around 40 participants will be enrolled in the US and Japan for the trial that will determine the maximum tolerated dose and recommended dose of DS-1055 for conducting further studies.

The safety endpoints of the trial will include analysis of dose-limiting toxicities and adverse events.

Efficacy endpoints of the trial will be objective response rate, disease control rate, duration of response, time to response, progression-free survival and overall survival.

The study will also evaluate pharmacokinetic, immunogenicity, and biomarker endpoints.