Ripretinib: A Review in Gastrointestinal Stromal Tumours as Fourth-or Later-Line of Therapy.

Ripretinib (Qinlock) is a small molecule inhibitor of the receptor tyrosine kinases KIT and platelet-derived growth factor receptor α (PDGFRA) and is approved for the treatment of gastrointestinal stromal tumours as a fourth-line of therapy. After successive cycles of treatment, gastrointestinal stromal tumours can carry a wide array of mutations, which makes resistance to treatment more likely. Ripretinib has a dual mechanism of action that allows it to target a broad spectrum of mutations in KIT or PDGFRA. The pivotal phase III INVICTUS trial demonstrated an increase of progression-free survival in patients receiving ripretinib compared with placebo, with efficacy being maintained across patients with KIT exon 9, 11, 13 and 17 mutations. Ripretinib has acceptable tolerability, with the most common drug-related grade 3 or 4 adverse events being lipase increases, hypertension, fatigue and hypophosphataemia. Ripretinib is therefore a valuable additional line of therapy available for the management of gastrointestinal stromal tumours.