Onward Therapeutics has commenced a Phase I clinical trial of its bispecific antibody, OT-A201.

The multicentre, open-label trial in Europe will assess the tolerability, safety, immunogenicity, pharmacokinetics and initial anti-tumoural activity of OT-A201 in treating various cancer types.

It will be conducted in two parts. The first portion involves a dose escalation stage to evaluate OT-A201 as monotherapy for specific relapsed/refractory haematological malignancies or advanced/metastatic solid tumours.

The second portion, an expansion stage, will focus on further assessing the initial anti-tumoural activity and safety of the antibody, as a single agent or as a combination regimen, in defined haematological malignancies and solid tumours. This part will assess the dose chosen from the initial portion.

This development follows Onward Therapeutics' acquisition of sole global rights for OT-A201 from Biomunex Pharmaceuticals in February 2021.

OT-A201, which targets two immune checkpoints, has shown promising results in preclinical studies, exhibiting specificity, safety and significant anti-tumoural activities at different doses.

These findings suggest a potential for a wider therapeutic window compared with its parental antibodies.

The antibody leverages Biomunex's BiXAb technology and includes a functional Fc domain that contributes to ADCC (antibody dependent cell-mediated cytotoxicity) activity against tumour cells.

The parties will jointly develop this bispecific antibody until the conclusion of the Phase I trial in one of the indications.

The dosing of the first patient also triggered the first clinical milestone payment from Onward to Biomunex, as per the 2021 deal terms.

Biomunex previously received an upfront payment and is entitled to receive milestone payments on meeting clinical, regulatory and commercial goals. These are in addition to royalties on global net product sales and other payments in the future.

Onward Therapeutics chairman and CEO Dr C Grace Yeh said: “With the drug development expertise and successful track records of the Onward Therapeutics team, we have moved forward from the cell line development, scale-up, 1,000l manufacture, preclinical pharmacology and toxicology studies, as well as clinical development and regulatory application of OT-A201 rapidly and efficiently.

“We are enthusiastic to test OT-A201 in patients for the first time. The study marks an important milestone of Onward Therapeutics in transitioning into a clinical-stage company.”