Bristol Myers Squibb (BMS) and BioNTech’s pumitamig has displayed promising efficacy and safety during a mid-stage trial in front and second-line triple-negative breast cancer (TNBC).
During the ongoing Phase II study (NCT06449222), the bispecific antibody triggered a nine-month progression-free survival (PFS) rate of 59.3% across 39 efficacy-evaluable patients who received a combination of pumitamig and chemotherapy agent, Abraxane (nab-placlitaxel).
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Alongside its PFS impact, pumitamig triggered a confirmed objective response (cORR) in 61.5% of patients while 71.8% achieved unconfirmed ORR.
Of the 39 patients enrolled in the first cohort, 92.3% experienced disease control.
Current data suggest that this impact was independent of a patient’s PD-L1 expression levels, as well as their previous treatment experience. Pumitamig’s impact was also dose-dependent, with higher doses correlating to a stronger anti-tumour response.
At the time of analysis, median overall survival (OS) and duration of response (DoR) were not mature.
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By GlobalDataAlongside its promising efficacy, pumitamig plus chemotherapy was fairly well tolerated, with severe treatment-emergent adverse events (TEAEs) rated Grade 3 or above occurring in 42.54% of the patients in the first cohort. There were no deaths related to pumitamig reported during the study.
The data was presented during the 2025 San Antonio Breast Cancer Symposium, taking place on 9-12 December in Texas, US.
PD-L1xVEGF combo piques pharma interest
Checkpoint inhibitors have been a resounding success story within the immuno-oncology sector, with programmed death ligand 1 (PD-1)-targeting drugs such as Keytruda (pembrolizumab) by Merck & Co (MSD) and BMS’s Opdivo (nivolumab) ranking as the first and third best-selling drugs in the segment in 2024.
While checkpoint inhibitors display strong efficacy on their own, companies are now looking to combine their anti-tumour activity with other promising targets. This includes vascular endothelial growth factor (VEGF) therapies, which have also been a popular monotherapeutic target in solid tumours.
Dr Balasz Halmos, thoracic oncologist at the Albert Einstein College of Medicine and Montefiore Medical Centre, previously told Clinical Trials Arena that PD-1xVEGF bispecifics were drawing a lot of interest from thoracic oncologists as they have shown strong activity in non-small cell lung cancer (NSCLC). Halmos highlighted Akeso’s ivonescimab as a drug to watch in NSCLC, but it is also being investigated in TNBC.
Pfizer has also bet on the PD-1×VEGF drug class, as it recently secured the exclusive global licence to 3SBio’s SSGJ-707 for $1.25bn in July 2025. The bispecific is currently in global development for NSCLC, metastatic colorectal cancer and gynaecological tumours.
Meanwhile, MSD is also betting on a PD-1xVEGF bispecific, having secured the global licence to LaNova Medicines’ LM-299 in 2024 for up to $2.7bn.
