According to the NCI website Tucatinib is an orally bioavailable inhibitor of the human epidermal growth factor receptor tyrosine kinase ErbB-2 (also called HER2) with potential antineoplastic activity.

Indikation gemäss Compendium.ch^®

TUKYSA in Kombination mit Trastuzumab und Capecitabin ist indiziert zur Behandlung von Patienten mit metastasiertem HER2-positivem Brustkrebs, die zuvor zwei oder mehr anti-HER2-Therapieregime in einem beliebigen Setting, einschliesslich Trastuzumab, Pertuzumab und Trastuzumab-Emtansin (T-DM1), erhalten haben (siehe «Klinische Wirksamkeit»).

Link zur Fachinformatio im Compendium.ch^®

SABCS December 2019 Study presentation with Tucatinib

Tucatinib FDA Approval Status - Drugs.com

Today, April 17, 2020, as part of Project Orbis, the U.S. Food and Drug Administration approved Tukysa (tucatinib) in combination with chemotherapy (trastuzumab and capecitabine) for the treatment of adult patients with advanced forms of HER2-positive breast cancer that can’t be removed with surgery, or has spread to other parts of the body, including the brain, and who have received one or more prior treatments.

More Information in English:

Link to Drug Information Portal, a service of the U.S. National Library of Medicine, National Institutes of Health
Link to National Cancer Institute
Link zu Wiki
Link to European Medicines Agency (EMEA)