Promising Trial Outcomes
BioNTech has announced encouraging findings from the main analysis of a Phase 2 cohort investigating trastuzumab pamirtecan, also known as BNT323 or DB-1303.
This novel antibody-drug conjugate is designed to target HER2-expressing cells and was evaluated in individuals with advanced endometrial cancer whose disease had advanced despite previous chemotherapy, with or without the addition of checkpoint inhibitors. This particular cohort is part of a broader global Phase 1/2a clinical trial that is exploring the potential of trastuzumab pamirtecan across various solid tumors. The gathered data highlights that BNT323, when used as a monotherapy, achieved clinically meaningful efficacy and presented a well-tolerated safety profile, irrespective of the level of HER2 expression. Notably, the outcomes were consistent even among patients who had previously received checkpoint inhibitor treatments, suggesting a robust therapeutic effect. These significant findings are set to be presented at the 2026 Society of Gynecologic Oncology Annual Meeting on Women’s Cancers in San Juan, Puerto Rico, during an oral session.
Detailed Patient Data
The Phase 2 cohort analysis specifically focused on 145 patients diagnosed with advanced or metastatic HER2-expressing endometrial cancer. These individuals had experienced disease progression after undergoing first-line or subsequent treatment regimens. The study's primary efficacy goal was to determine the objective response rate (ORR). This endpoint was met by evaluating 73 patients who had previously been treated with checkpoint inhibitors and whose HER2 status was confirmed through central testing. For this subgroup, the confirmed ORR stood at an impressive 49.3%. When considering all centrally tested patients within the cohort, the confirmed ORR was 47.9%. Furthermore, the median progression-free survival (PFS) observed in these patients was 8.1 months, indicating a substantial period where the disease remained stable or improved under treatment with trastuzumab pamirtecan.
