Are Rogerofenib and Nilotinib Effective for Advanced Gastrointestinal Stromal Tumor (GIST) Patients who have Already been Given Main Treatments?

Patients with GISTs most commonly have KIT and PDGFRA mutations. The therapeutic agents are determined based on these sites of mutation. Imatinib and sunitinib are proven to be effective against GIST, and these agents are now the standard treatment options for GISTs. Moreover, several novel molecular-targeted agents are under development, particularly regorafenib and nilotinib which have phase III trials. In these trials, it has been shown to contribute of survival with regorafenib but longer survival has not obtained with nilotinib. We have two cases who were responder with regorafenib and nilotinib in the fifth-line therapy. First case, a 45-year-old male patient who had GIST in small intestine with multipl liver metastases. C-KIT gene mutation analysis was performed on the pathology preparation which has indicated an exon 11 deletion. In the immunohistochemical evaluations, it was found that there was positive staining for CD34 and SMA. Imatinib 400 mg/day had been initiated and it had been used for 7 years. After progression imatinib dose was increased to 800 mg/day, then the patient was shifted to treatment with sunitinib, then treated with sorafenib for 14 months, 2 months, 1 month, respectively. An ileus had occured after a month of sorafenib treatment. This was considered as clinical progression and then the patient was shifted to treatment of regorafenib (160 mg/day). The ileus symptoms markedly regressed on the 7th day of regorafenib treatment and completely resolved on the 14th day (Figure 1). The patient died at the 10th month of treatment with regorafenib due to liver failure. Second case, a 40-year-old female patient who had GIST in stomach with multipl liver metastases. C-KIT and PDGRFA gene mutation analysis was performed on the pathology preparation which has indicated no mutation LETTER to the EDITOR