Prospective phase II trial of everolimus in PIK3CA amplification/mutation and/or PTEN loss patients with advanced solid tumors refractory to standard therapy

BACKGROUND: We designed a single-arm, open-label phase II trial of everolimus in PIK3CA amplification/mutation and/or PTEN loss patients with advanced solid tumors refractory to standard therapy (#NCT02449538). METHODS: Everolimus was administered orally at a daily dose of 10 mg continuously (28-day cycles). Treatment was continued until progression of the disease or intolerable toxicity was observed. Based on Simon’s two-stage optimal design, 10 patients were treated with everolimus during the first stage. RESULTS: The median age of the patients was 55.5 years (range, 42–72), and the median Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 2 (range, 1–2). Most of the patients (50.0%) had gastric cancer (GC) as the site of their primary tumor followed by colorectal cancer (CRC), pancreatic cancer, and cholangiocarcinoma. Patients received everolimus as a third-line (3 patients), fourth-line (4 patients), fifth-line (1 patient) or sixth-line (2 patients) treatment. Complete or partial responses were not observed in any of the patients. Four patients showed stable disease, resulting in a disease control rate of 40%. The median PFS was 1.6 months (95% CI, 0.8–2.4 months). Grade 3 or greater hematologic/non-hematologic toxicity was not observed. Grade 2 diarrhea and stomatitis were reported in one patient each. There were no treatment-related deaths. There was less than one response out of the 10 initial patients during the first stage, and the study did not progress to the second stage. CONCLUSIONS: The study did not meet its primary objective of demonstrating the anti-tumor activity of everolimus in PIK3CA amplification/mutation and/or PTEN loss patients with advanced solid tumors refractory to standard therapy. Further investigation using other genomic candidates and new-generation mTOR inhibitors is warranted in patients with treatment-refractory cancer. TRIAL REGISTRATION: #NCT02449538, April 2015.