Pumitamig (BNT327) is a new bispecific antibody showing promise for patients with metastatic triple-negative breast cancer, including those who are PD-L1 negative and previously had limited immunotherapy options.
The drug works by targeting two pathways at once: it blocks PD-L1 to unleash T cells against tumors and inhibits VEGF to stop tumor blood vessel growth. This dual action helps immune cells reach tumors more effectively and may overcome resistance to standard therapies.
In a global Phase 2 trial, pumitamig combined with chemotherapy showed strong results: a confirmed response rate of 61.5%, disease control in 92.3% of patients, and a 50% or greater drop in tumor DNA in nearly all high-dose patients by Cycle 3. Side effects were manageable, mainly high blood pressure and protein in the urine.
The drug is now advancing to the Phase 3 ROSETTA Breast-01 trial, focusing on PD-L1 negative patients to establish a new frontline option. Future studies may explore combining pumitamig with antibody-drug conjugates like Trodelvy for even greater benefit.