What it is
Pumitamig is an investigational bispecific antibody, one that binds two targets at once: PD-L1, which tumours use to dampen immune attack, and VEGF-A, which drives tumour blood-vessel growth. It had shown preliminary efficacy across several tumour types. In this single-arm phase 1b/2 trial at ten sites in China, 42 patients with unresectable, locally advanced or metastatic triple-negative breast cancer received pumitamig plus the chemotherapy nab-paclitaxel as first-line treatment until their disease progressed or toxicity became unacceptable. The primary endpoints were confirmed objective response rate and safety. At a median follow-up of 35.2 months, the confirmed objective response rate was 73.8%, with one complete and 30 partial responses. The most frequent grade 3 or worse treatment-related events were decreased neutrophil count (13 of 42) and decreased white blood cell count (11), with proteinuria in six and febrile neutropenia in five; there were no treatment-related deaths. The authors call the activity encouraging and the safety profile consistent with both agents' modes of action, which the authors say warrants further clinical evaluation in global phase 2 and 3 trials.
Why it matters
Triple-negative breast cancer lacks the receptors other breast-cancer drugs target, so first-line options are limited. A response in 31 of 42 patients is why the authors call for larger trials. Combining immune checkpoint and blood-vessel blockade in one antibody is the design being tested here, alongside standard chemotherapy, and treatment lasted a median of 9.0 months.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed underBreast Cancer Treatment Studies, Cancer Immunotherapy and Biomarkers, Advanced Breast Cancer Therapies
