Legionowo

Researchers are evaluating treatments for advanced breast cancer that is hormone receptor HR-positive and HER2-low or ultralow, classified as non-luminal subtype by gene expression profiling PAM50. This phase II international study compares trastuzumab deruxtecan T-DXd with a physicians choice of CDK46 inhibitor plus endocrine therapy ET to see which better prolongs progression-free survival in these patients. Participants will be randomly assigned to receive either T-DXd at 5.4 mgkg body weight by intravenous infusion every 21 days or one of several CDK46 inhibitors palbociclib, ribociclib, or abemaciclib combined with an endocrine therapy fulvestrant, letrozole, anastrozole, or exemestane chosen by their doctor. Treatment will continue in 21-day cycles, and the study will assess outcomes over up to 25 months. During the study, participants will undergo regular assessments including imaging scans to evaluate tumor response and progression. Researchers will monitor progression-free survival, overall survival, response rates, quality of life, and safety through adverse event tracking. Follow-up and treatment adherence will be closely observed to understand the effects and tolerability of these therapies in this specific breast cancer subtype.