Daiichi Sankyo Company and Sarah Cannon Research Institute have dosed the first patient in a Phase I/II study evaluating DS-7300 for the treatment of patients with advanced solid tumours.

Around 160 patients are expected to be enrolled in the US and Japan for the first-in-human study of B7-H3-targeting antibody-drug conjugate (ADC) DS-7300.

The strategic oncology partnership between the two organisations has been designed to accelerate and optimise the global clinical development of Daiichi Sankyo’s ADCs and other targeted cancer therapies.

This will involve the combination of the operational and scientific expertise of Daiichi Sankyo and Sarah Cannon.

As part of the open-label Phase I/II study, the safety, tolerability and preliminary activity of DS-7300 will be evaluated in adult patients with advanced/unresectable or metastatic solid tumours.

The dose-escalation part of the study will evaluate the safety and tolerability of increasing doses of DS-7300 for determining the maximum tolerated dose (MTD) and recommended dose for expansion (RDE).

For this portion of the trial, around 40 patients with tumour types including advanced/unresectable or metastatic squamous cell head and neck cancers, squamous cell esophageal cancer, and squamous/adenocarcinoma cell non-small cell lung cancer (NSCLC) will be enrolled.

The dose-expansion part of the study will include three cohorts of 40 patients each and will assess the safety, tolerability and preliminary activity of DS-7300.

DS-7300 uses Daiichi Sankyo’s DXd technology and has been designed to target and deliver chemotherapy inside cancer cells expressing the B7-H3 protein.

Daiichi Sankyo executive vice-president and Oncology Research and Development global head Antoine Yver said: “This first-in-human Phase I/II trial will evaluate the potential for DS-7300 to serve as a new mode of targeted therapy for patients with several types of advanced cancers where the B7-H3 protein is overexpressed.

“Based on our preclinical assessments, the trial will focus initially on patients with non-small cell lung, head and neck, esophageal, and other cancers.”

DS-7300 has been engineered with the DAR-controlled conjugation technology of Daiichi Sankyo to create a drug-to-antibody ratio (DAR) of four.