HER2-positive metastatic breast cancer is caused by the overexpression of HER2, which may contribute to tumor growth, metastasis, and poor prognosis. Kadcyla, an FDA-approved HER2-targeted antibody-drug conjugate, selectively binds to HER2 receptors on cancer cells, delivering a cytotoxic agent directly into the cells to inhibit cell proliferation and induce cell death.
The recommended dose of KADCYLA is 3.6 mg/kg given as an intravenous infusion every 3 weeks (21-day cycle). The first infusion should be administered over 90 minutes. If prior infusions are well tolerated, subsequent infusions may be administered over 30 minutes. For metastatic breast cancer (MBC), treatment continues until disease progression or unmanageable toxicity. Permanently discontinue KADCYLA for life-threatening infusion-related reactions.
Serious side effects include liver toxicity, cardiotoxicity, lung disease, infusion-related reactions, and embryo-fetal toxicity. Serious allergic or anaphylactic-like reactions have been observed in clinical trials of single-agent KADCYLA, and medications to treat such reactions, as well as emergency equipment, should be available for immediate use. Common side effects include fatigue, nausea, musculoskeletal pain, hemorrhage, thrombocytopenia, headache, increased transaminases, constipation and epistaxis. Immediate medical attention is required for severe symptoms, including shortness of breath, jaundice, or significant bleeding.