Treatment in patients with HER2-positive (+), metastatic breast cancer (MBC) who previously received trastuzumab and a taxane, separately or in combination. Patients should have either: received prior therapy for metastatic disease or developed disease recurrence during or within
6 months of completing adjuvant therapy.
Give by IV infusion only over 90 minutes 3.6mg/kg max every 3 weeks (21-day cycle) until disease progression or unacceptable toxicity. Subsequent infusions may be given over 30 minutes if previously tolerated. Monitor closely for possible SC infiltration during infusion. Dose modifications: see full labeling.
HER2-targeted antibody-drug conjugate.
Do not substitute for or with trastuzumab. Hepatotoxicity; monitor serum transaminases and bilirubin prior to starting and to each dose; reduce dose or discontinue if occurs. Risk of left ventricular dysfunction. Assess LVEF prior to initiation and every 3 months during treatment; interrupt and discontinue as appropriate. Risk of embryo-fetal toxicity. Permanently discontinue if interstitial lung disease or pneumonitis occurs. Monitor for signs/symptoms of extravasation, infusion-related or hypersensitivity reactions; if significant, slow or interrupt infusion; discontinue if life-threatening. Monitor platelets at baseline and prior to each dose; if platelets <50,000/mm3, delay dose until recovery to ≥75,000/mm3; if platelets <25,000/mm3, delay until recovery to ≥75,000/mm3 and reduce dose. If thrombocytopenia occurs <100,000/mm3 and concomitant anticoagulants, monitor closely. Monitor for neurotoxicity; withhold temporarily if Grade 3 or 4 peripheral neuropathy occurs. Test for HER2 protein overexpression or gene amplification using FDA-approved tests by labs with demonstrated proficiency. Pregnancy (Category D); use adequate contraception during and at least 6 months after last dose. Nursing mothers: not recommended.
Avoid concomitant strong CYP3A4 inhibitors (eg, azole antifungals, clarithromycin, atazanavir, indinavir, ritonavir, nefazodone, nelfinavir, saquinavir, telithromycin); if unavoidable, consider delaying therapy (see full labeling).
Fatigue, nausea, musculoskeletal pain, thrombocytopenia, headache; increased transaminases, constipation.