Ripretinib in treatment of repeatedly relapsing rectal gastrointestinal stromal tumor: a case report

Abstract

Gastrointestinal stromal tumor (GIST) is the most common type of gastrointestinal mesenchymal tumor. Fewer than 2% of patients with metastatic GIST treated with imatinib experience a pathologic complete response. Furthermore, response to imatinib and subsequent-line tyrosine kinase inhibitor is limited by most patients developing drug resistance; median time to progression is 2 years for imatinib, and about half a year for sunitinib and regorafenib. In recent years, ripretinib, a fourth-line medicine, is been of the most important advances in the treatment of GIST. The ripretinib in patients with advanced gastrointestinal stromal tumours (INVICTUS): a double-blind, randomised, placebo-controlled, phase 3 trial study showed that ripretinib can significantly reduce the risk of disease progression and mortality in patients with advanced GIST ≥4 lines, and has obvious clinical activity for a variety of KIT/platelet-derived growth factor receptor α (PDGFR α) gene mutations. This paper presents a case of advanced rectal GIST treated with ripretinib in China. In the years preceding, the patient did not respond well to first-third line agent therapies. However, a partial remission (PR) of the tumor was found after 3-courses of ripretinib treatment. For GIST patients with drug-resistant mutations (both primary and secondary), treatment may be a more accurate and reasonable when mutation-inhibitor agents are prescribed at an early stage.