04:49 AM EDT, 05/23/2025 (MT Newswires) -- Merus (MRUS) said late Thursday that interim data from a phase 2 trial of the bispecific antibody petosemtamab in combination with pembrolizumab showed "robust" efficacy and durability as a first-line treatment of PD-L1+ recurrent/metastatic head and neck squamous cell carcinoma.

Based on a Feb. 27 cutoff, the data showed a 63% overall response rate in 43 evaluable patients, including six complete responses, as well as a 79% survival rate at 12-months, according to the company.

"By essentially every metric, we believe these interim data are significantly better than pembrolizumab monotherapy, the control arm of our ongoing phase 3 trial, and underscores the opportunity petosemtamab holds to become a new standard of care, if approved, in head and neck cancer," Chief Executive Bill Lundberg said.

The company plans to share top line interim readout of one or both of its phase 3 trials next year, Lundberg said.

Merus shares were up 8.9% in recent premarket activity Friday.