Phase III Study to Determine the Optimal Dose and Evaluate Safety of BNT323 Combined With BNT327 for Advanced Breast Cancer

What this Trial Is About

Researchers are evaluating the safety, efficacy, and optimal dosing of a combination of two investigational treatments, BNT323 trastuzumab pamirtecan and BNT327 pumitamig, in people with advanced breast cancer. This includes those with hormone receptor-positive or -negative, HER2-positive, HER2-low, HER2-ultralow, HER2-null breast cancer, or triple-negative breast cancer. The study is a Phase III multi-site, open-label trial with a focus on advanced breast cancer treatment options. The study has two parts. Part 1 involves dose escalation of BNT323 combined with BNT327 to determine the recommended Phase 2 dose using six different dose levels. Part 2, which begins after Part 1 completion, includes dose optimization and exploratory cohorts. Cohort 1 in Part 2 uses randomization into four treatment arms, including combination therapy at different doses and monotherapies of either BNT323 or BNT327. Other cohorts receive the recommended dose without randomization. Participants will undergo assessments including tumor scans and cardiac function tests, with monitoring for side effects and tumor response up to 36 months. Researchers will track dose-limiting toxicities and treatment-emergent adverse events during early treatment cycles and monitor objective response rates and disease control over time. Safety and efficacy data will be collected through scheduled visits and tumor assessments during and after treatment to evaluate the study drugs effects and tolerability.

A Clinical Study to Find the Optimal Dose of an Investigational Treatment Called BNT323 When Used in Combination With Another Investigational Treatment, BNT327, and to Test if That Combination Treatment is Safe and Beneficial for Patients With Advanced Breast Cancer