Study on Patritumab Deruxtecan for Treating Breast Cancer (MK-1022-016)

Inclusion Criteria

• Diagnosed with hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer that cannot be surgically removed or has spread to other parts of the body.
• Cancer must be confirmed as HR+ and HER2- from a biopsy taken from a distant site or a locally advanced tumor after the most recent treatment.
• Must have experienced cancer progression or return after previous treatment with a CDK4/6 inhibitor and endocrine therapy (ET).
• Must have measurable cancer according to specific medical criteria.
• HIV-positive participants must have well-controlled HIV on antiretroviral therapy.
• Must have a good overall health status with an ECOG performance score of 0 or 1.

Exclusion Criteria

• Breast cancer that can be treated with the intent to cure.
• Eligible for additional endocrine-based treatment in the advanced setting.
• Known BRCA gene mutation where PARP inhibitors could be a treatment option.
• Current or risk of severe organ complications due to cancer.
• Low oxygen levels or need for supplemental oxygen.
• Uncontrolled heart or blood vessel diseases.
• Significant nerve damage or eye disease.
• Previous chemotherapy for advanced breast cancer.
• Previous treatment with anti-HER3 drugs or certain topoisomerase I inhibitors.
• Recent systemic cancer therapy or radiation therapy.
• Diagnosis of immunodeficiency or on long-term steroid therapy.
• Other active cancers within the past 3 years.
• History of lung disease requiring steroids or current lung issues.
• Severe allergy to patritumab deruxtecan or its components.