Phase 2 Trial Results
BioNTech and its partner Bristol Myers Squibb (BMS) have presented the first global data from a mid-stage trial evaluating pumitamig (BNT327), a PD-L1xVEGF bispecific antibody, in small cell lung cancer. Results were shared at the 2025 World Conference on Lung Cancer.
The phase 2 trial tested pumitamig in combination with chemotherapy in treatment-naïve patients with extensive-stage small cell lung cancer (ES-SCLC). Among 38 evaluable patients, the regimen achieved a confirmed overall response rate (ORR) of 76.3%. BioNTech’s chief medical officer, Özlem Türeci, M.D., described the findings as “very consistent” with earlier data generated in China.
The median duration of response (DoR) in the global trial was five months, with all patients considered to have their disease under control at the time of the analysis. The data cutoff occurred on August 7, with patients receiving pumitamig at either 20 mg/kg or 30 mg/kg. The ORR was 85% at the lower dose and 66.7% at the higher dose. Türeci cautioned against overinterpreting this inverse relationship due to the small sample size within each subgroup.
Median progression-free survival (PFS) reached 6.8 months overall, measuring 6.3 months for the 20 mg/kg group and seven months for the 30 mg/kg group. Median overall survival was not yet mature.
Safety Profile
In terms of safety, 43 patients were evaluated. No new safety concerns emerged beyond those already known for chemotherapy, checkpoint inhibitors, and anti-VEGF therapies. Grade 3 or higher pumitamig-related adverse events occurred in one patient in the lower-dose arm and five patients in the higher-dose arm. No treatment-related deaths were reported.
Favorable Comparison and Future Steps
Türeci noted that the results compared favorably with historical benchmarks for the current first-line standard of care, which combines chemotherapy with Roche’s Tecentriq. That earlier regimen, tested in the IMpower133 phase 3 trial, had achieved a 60% ORR, 4.2 months of median DoR, and 5.2 months of median PFS.
Bryan Campbell, BMS’ head of program leadership for hematology, oncology, and cell therapy, said the global findings aligned with the earlier China-only study and supported advancement into phase 3. “I think it supports our approach to move into phase 3, which is ongoing,” Campbell said.
The ongoing Rosetta Lung-01 phase 3 trial is evaluating pumitamig in combination with chemotherapy against Tecentriq plus chemotherapy. Based on the phase 2 data, BioNTech and BMS have selected a fixed dose of 1500 mg every three weeks, or 1200 mg for patients under 50 kg, equivalent to the 20 mg/kg regimen. The companies plan to discuss this dosing decision with the U.S. Food and Drug Administration.
Broader Applications
Beyond lung cancer, BioNTech and BMS are exploring pumitamig as a backbone for additional immunotherapy combinations. Studies are underway pairing it with antibody-drug conjugates (ADCs) such as BNT324, BNT325, and BNT323 across indications including lung and breast cancers. A phase 3 trial in triple-negative breast cancer is expected to begin later this year.
