Tykerb

Tykerb is the brand name for lapatinib, an oral small-molecule tyrosine kinase inhibitor developed for the treatment of HER2-positive breast cancer. It targets the kinase activity of two receptors, EGFR (HER1) and HER2, reducing signaling pathways that promote tumor cell growth and survival.

Indications for lapatinib include treatment of advanced or metastatic HER2-overexpressing breast cancer in combination with the chemotherapy capecitabine after progression on prior therapy. It has also been studied in combination with hormonal therapy, such as letrozole, for postmenopausal women with HR-positive, HER2-positive metastatic breast cancer following aromatase inhibitor therapy.

Mechanism of action involves reversible inhibition of the intracellular tyrosine kinases of both EGFR and HER2, which can slow tumor growth and promote cancer cell death in tumors dependent on these pathways.

Administration and dosing are oral, typically once daily. Lapatinib should be taken on an empty stomach, at least 1 hour before or 2 hours after a meal. When used with capecitabine or other agents, dosing may follow specific regimen guidelines set by a clinician.

Common adverse effects include diarrhea, rash, nausea, fatigue, and mucositis. Hepatotoxicity with elevated liver enzymes has been reported, so liver function monitoring is advised. Cardiac effects, including decreases in left ventricular ejection fraction, can occur; patients should be evaluated for cardiotoxicity during treatment. Rare cases of QT prolongation have been observed. Lapatinib is metabolized mainly by CYP3A4, so concomitant strong inhibitors or inducers may affect drug levels and require monitoring or dose adjustments.

Tykerb received FDA approval in 2007 and is marketed by GlaxoSmithKline for HER2-positive breast cancer.