Bicycle Therapeutics doses first patient in Bicycle Toxin Conjugate BT8009

Bicycle Therapeutics announced the first patient has been dosed in the Phase I dose escalation portion of a company-sponsored Phase I/II trial of BT8009, a Bicycle Toxin Conjugate targeting Nectin-4. BT8009 is a second-generation BTC, which uses a valine-citrulline cleavable linker and a cytotoxin MMAE payload. It targets Nectin-4, which is a well-validated tumor antigen. Overexpression of Nectin-4 has been observed in several common tumor types and is associated with poor disease prognosis. The Phase I/II trial of BT8009 will be conducted in patients with advanced solid tumors associated with Nectin-4 expression. The Phase I/II multi-center, open-label trial will evaluate BT8009 administered once weekly. Enrollment is ongoing in the Phase I dose escalation of BT8009 given as a monotherapy, and the Company plans to evaluate BT8009 dosed in combination with an immune checkpoint inhibitor in future Phase I dose escalation cohorts. The Phase I portion of the trial is primarily designed to assess the safety and tolerability of BT8009, and to determine a recommended Phase II dose. Following selection of an RP2D, Bicycle expects to initiate a Phase II dose expansion portion with the primary objective of evaluating the clinical activity of BT8009 in patients with Nectin-4-positive tumors.