Under this collaboration, Hummingbird will evaluate the safety, tolerability, and anti-tumor activity of its novel anti-VISTA antibody, HMBD-002, in combination with KEYTRUDA® (pembrolizumab), Merck's anti-PD-1 therapy, in patients with triple negative breast cancer (TNBC), non-small cell lung cancer (NSCLC) and other cancers with high VISTA expression. HMBD-002 is anticipated to enter a Phase 1 clinical trial in 2021.

VISTA is a co-inhibitory immune checkpoint receptor that is involved in suppressing an anti-tumor immune response. Overexpression of VISTA in the immune cells in tumors has also been associated with acquired resistance to other checkpoint therapies, such as anti-PD1 therapies. TNBC and NSCLC were identified as priority indications for clinical investigation based on the unmet need for new treatment options and widespread expression of VISTA in these tumor types. HMBD-002 is the only IgG4 isotype anti-VISTA antibody currently in development. It is precisely engineered to bind to VISTA at a specific site that is predicted to be essential for ligand-binding and function, and thereby inhibits VISTA by neutralizing its immunosuppressive activity without depleting other VISTA expressing cells that play many important roles in the immune system. Preclinical studies have demonstrated potent anti-tumor activity both as single agent and in combination with PD-1 therapy.

"Our preclinical studies have shown that VISTA in combination with PD-1 therapy can enhance anti-tumor activity. We look forward to initiating clinical trials for HMBD-002 as we aim to develop new treatment options for patients who do not respond to existing therapies," said Piers Ingram, Chief Executive Officer and co-founder of Hummingbird.