German biotech company BioNTech and US- based pharma giant Bristol Myers Squibb have unveiled the first interim results from a global Phase 2 trial of pumitamig in patients with locally advanced or metastatic triple-negative breast cancer (TNBC).

The early readout suggests the drug -- bispecific antibody designed to hit both PD-L1 and VEGF-A, paired with chemotherapy, may offer a badly needed new option for one of the most aggressive breast cancer subtypes.

“Triple-negative breast cancer is a highly aggressive disease with a poor prognosis and 5-year survival rate of just 15% in advanced stages.1 There remains an urgent need for new treatment options – particularly for patients with PD-L1 low or negative tumors (CPS<10), a subgroup for whom the current standard of care is chemotherapy alone and existing PD-(L)1 inhibitors have historically shown limited benefit,” said Peter Schmid.

“The anti-tumor efficacy observed in this interim analysis is encouraging and supports the ongoing investigation of pumitamig in the Phase 3 ROSETTA BREAST-01 trial.”

The Phase 2 study tested two dose levels of pumitamig alongside four standard chemotherapy regimens across first- and second-line settings. In the cohort included in the interim review, patients received pumitamig plus nab-paclitaxel; a second cohort evaluated the flat-dose equivalent with paclitaxel, gemcitabine/carboplatin, or eribulin.

Among 39 efficacy-evaluable patients, all from Cohort 1, the confirmed objective response rate hit 61.5%, while the unconfirmed response rate reached 71.8%. Disease control climbed to 92.3%. Responses appeared consistent across PD-L1 expression levels and treatment lines, with a trend toward stronger activity at the higher dose. At nine months, progression-free survival stood at 59.3%, though median PFS, duration of response, and overall survival have not yet matured.

Across both cohorts, pumitamig showed a manageable safety profile paired with all four chemotherapy backbones. Rates of Grade ≥3 treatment-related adverse events were 42.5% in Cohort 1 and 38.2% in Cohort 2, and no deaths were attributed to the drug.

“We are encouraged by these first locally advanced/metastatic TNBC data from a global patient population that indicate the potential of pumitamig in patients with advanced TNBC irrespective of PD-L1 status,” said Prof. Özlem Türeci.

“The activity we see in TNBC is consistent with findings in other solid tumors and further supports the pan-tumor potential of pumitamig, which we are advancing together with BMS in a broad development program that also includes novel/novel combination regimens.”

“These data add to the growing evidence from global pumitamig studies across multiple indications,” added Anne Kerber.

“The encouraging results are especially meaningful in patients with PD-L1 low or negative tumors (CPS<10), representing the potential of pumitamig to deliver meaningful benefit across PD-L1 expression levels, including patients who historically have had fewer effective treatments.”

The companies are already pushing forward with ROSETTA-BREAST-01, a global Phase 3 trial comparing pumitamig plus chemotherapy against placebo-chemotherapy in previously untreated TNBC patients who are PD-L1 negative and thus ineligible for PD-(L)1 therapy.