BioInvent International AB and Transgene announced that their Investigational New Drug (IND) application for BT-001 has been granted by the U.S. Food and Drug Administration (FDA). This IND will allow patients in the U.S. to be enrolled into the ongoing Phase 1/2a clinical trial of this novel oncolytic virus BT-001. BT-001 is armed with both a differentiated Treg-depleting human recombinant anti-CTLA4 antibody and GM-CSF.

The ongoing Phase 1/2a study is a multicenter, open label, dose-escalation trial evaluating BT-001 as a single agent and in combination with pembrolizumab. The Phase 1 part of the trial has already been initiated in Europe, where it is enrolling patients in several countries. BT-001 is expected to elicit a strong and effective antitumoral response by selectively targeting and modulating the tumor microenvironment.

In addition, delivering the anti-CTLA4 antibody directly to the tumor aims to induce local Treg depletion and strong therapeutic activity. As a consequence, the safety and tolerability profile of the anti-CTLA4 antibody is expected to be greatly improved due to reduced systemic exposure. BT-001 is being codeveloped through a 50/50 collaboration between BioInvent and Transgene.

The Phase 1 trial is divided into two parts. Part A will enroll up to 36 patients with metastatic/advanced solid tumors. Patients will receive single agent, intra-tumoral administrations of BT-001.

Part B will explore the combination of intra-tumoral injections of BT-001 with the standard treatment regimen of pembrolizumab in 12 patients. The Phase 2a part of the trial will evaluate BT-001-based combination regimen in several patient cohorts with different tumor types. These expansion cohorts will offer the possibility of exploring the activity of this approach to treat other malignancies not traditionally addressed with this type of treatment.