Boundless Bio has signed a clinical trial collaboration and supply agreement with Taiho Oncology to evaluate the combination of BBI-355 and LYTGOBI (futibatinib) for the treatment of locally advanced or metastatic solid tumours with oncogene amplifications in a Phase I/II study.

Under the agreement, Taiho will supply its pan-FGFR inhibitor LYTGOBI at no cost for the Phase I/II Precision Oncology Trial Evaluating Novel Therapeutic Interrupting Amplifications Tied to ecDNA (POTENTIATE) study.

The three-part, non-randomised, open-label will assess Boundless Bio’s CHK1 inhibitor BBI-355 along with LYTGOBI in patients with specific oncogene amplified solid tumours.

Boundless Bio president and CEO Zachary Hornby said: “This clinical trial collaboration and supply agreement with Taiho marks an important step in the continued execution of our clinical strategy and the next step in realising the transformative potential of BBI-355, which we believe is the first extrachromosomal DNA (ecDNA)-directed therapy in development for patients with cancer that harbour oncogene amplifications on ecDNA.

“FGFR inhibitors given as monotherapy have to date demonstrated less clinical benefit in patients with cancer harbouring FGFR amplifications than in patients with other FGFR driver alteration types.

“We believe that BBI-355, when combined with Taiho’s futibatinib, has the potential to demonstrate meaningful anti-tumour activity for patients with cancer and FGFR amplifications.”

The trial includes a single agent dose escalation and expansion studies of BBI-355, as well as combination studies with certain selected targeted therapies.

In the study, patients will receive oral BBI-355 every other day.