Bio-Thera Solutions has reported positive Phase I clinical data evaluating BAT8006 for the treatment of advanced solid tumours.

An antibody-drug conjugate (ADC), BAT8006 is made of an anti-FRα antibody and an ADC linker-payload combination that consists of a cleavable linker, which is claimed to be highly systemically stable and a small molecule topoisomerase I inhibitor.

Conducted at the First Bethune Hospital of Jilin University, the study was led by Professor Songling Zhang who acted as a co-principal investigator.

Professor Zhang also presented Phase I dose-escalation results from the study at the Bethune Obstetrics and Gynecology Forum.

A total of 29 subjects with advanced solid tumours having a minimum of one tumour assessment with an overall objective response rate (ORR) of 31.0% and a disease control rate (DCR) of 86.2% were enrolled.

In the dose-escalation trial, these patients were recruited into four dose cohorts – 1.2mg/kg, 1.8mg/kg, 2.1mg/kg and 2.4mg/kg.

About 60% (15) of the subjects enrolled in the study were ovarian cancer patients, who were in the 2.1 mg/kg and 2.4 mg/kg cohorts.

The remaining patients enrolled in the study had breast cancer, non-small cell lung cancer and cervical cancer.

In 12 ovarian cancer patients with a TPS of more than 25%, the ORR was found to be 58.3% and the DCR at 91.7%.

As per the FRα expression epidemiological studies, it is estimated that about 75% of ovarian cancer patients have FRα expression more than 25%.

Most of these ovarian cancer patients had received more than three prior anti-tumour therapy that included bevacizumab and PARPi. 

Furthermore, two subjects with breast cancer and endometrial carcinoma experienced partial responses.

Overall, a manageable safety profile of BAT8006 was demonstrated while gastrointestinal toxicity, including nausea and vomiting, as well as haematological toxicity such as neutropenia, thrombocytopenia and anaemia were reported.

No observations of safety issues such as interstitial lung disease, ocular toxicity and severe hepatotoxicity were seen.

The company is also evaluating BAT8006 in a Phase Ib study in China with four dose expansion cohorts. Each patient subgroup is intended to receive two different doses of BAT8006.

It is also planning to expand the BAT8006 clinical programme in Europe and the US.