BioNTech And Bristol Myers Report Early Data For New Triple-Negative Breast Cancer Treatment

BioNTech SE (NASDAQ:BNTX, "BioNTech"))) and Bristol Myers Squibb Company (NYSE:BMY, "BMS"))) today announced the first interim data from a global randomized Phase 2 trial (NCT06449222) evaluating pumitamig (BNT327/BMS986545), an investigational bispecific antibody targeting PD-L1 and VEGF-A, plus chemotherapy in patients with locally advanced/metastatic triple-negative breast cancer ("TNBC") irrespective of PD-L1 expression levels.

The data showed encouraging anti-tumor responses and a manageable safety profile for pumitamig plus chemotherapy in first-line and second-line treatment setting. The data will be presented at the 2025 San Antonio Breast Cancer Symposium ("SABCS").

"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, M.D., Ph.D., Lead Investigator and Director of the Breast Cancer Centre at St. Bartholomew's Hospital, London, UK. "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 trial evaluated pumitamig in two dose levels and in combination with four different chemotherapeutic agents in the first- and second-line treatment of participants with locally advanced/metastatic TNBC. In Cohort 1, reported in this analysis, patients received pumitamig (15 or 20 mg/kg Q2W) plus nab-paclitaxel until disease progression or unacceptable toxicity. In Cohort 2, patients received the flat-dose equivalent of 20 mg/kg in combination with three different chemotherapy regimens (Arm 1: paclitaxel; Arm 2: gemcitabine + carboplatin; Arm 3: eribulin).

The interim analysis at the October 1, 2025 data cut-off included 74 patients with 1L/2L+ locally advanced/metastatic TNBC who received pumitamig in combination with standard of care chemotherapy. Key data highlights are provided below:

Efficacy:

• Among 39 efficacy-evaluable first-line and second-line patients, all in Cohort 1, the confirmed objective response rate ("cORR") was 61.5% (24/39), the unconfirmed objective response rate ("uORR") was 71.8% (28/39) and the disease control rate ("DCR") was 92.3% (36/39).
• Efficacy was encouraging across dose levels, PD-L1 expression levels and lines of treatment and higher doses correlated with higher response (dose levels: uORR: 63.2% at 15 mg/kg dose; 80.0% at 20 mg/kg dose; PD-L1 expression levels: uORR: 70.6% in CPS ≥10; 70.6% in CPS <10; lines of treatment: uORR: 76.5% in 1L and 68.2% in 2L).
• The progression-free survival ("PFS") rate at 9 months was 59.3%. Median PFS, median duration of response ("DOR") and median overall survival ("OS") were not mature at the time of analysis.

Safety:

• Pumitamig plus chemotherapy demonstrated a manageable safety profile in both Cohorts in combination with all four chemotherapy regimens.
• Grade ≥3 treatment-related adverse events (TRAEs) were reported in 17/40 (42.54%) and 13/34 (38.2%) patients in Cohorts 1 and 2, respectively, with no pumitamig-related deaths reported.

"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, M.D., Co-Founder and Chief Medical Officer at BioNTech. "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," said Anne Kerber, Senior Vice President, Head of Development, Hematology, Oncology, Cell Therapy at Bristol Myers Squibb. "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."

A global randomized Phase 3 trial, ROSETTA-BREAST-01 (NCT07173751), is evaluating pumitamig plus chemotherapy versus placebo plus chemotherapy in patients with previously untreated locally advanced/metastatic TNBC determined ineligible for PD-(L)1 therapy based on PD-L1 negative disease. Pumitamig is also being studied in more than 20 clinical trials as monotherapy, in combination with chemotherapy, or with other novel treatment modalities in more than 10 solid tumor indications.