Phase II Trial of Cabozantinib in Recurrent/Metastatic Endometrial Cancer: A Study of the Princess Margaret, Chicago and California Consortia (NCI9322/PHL86).

The relevance of the MET/Hepatocyte Growth Factor (HGF) pathway in endometrial cancer tumor biology supports the clinical evaluation of cabozantinib in this disease.PHL86/NCI#9322 (NCT01935934) is a single arm study that evaluated cabozantinib in women with endometrial cancer with progression after chemotherapy. Co-primary endpoints were response rate and 12-week progression-free-survival (PFS). Patients with uncommon histology endometrial cancer (eg carcinosarcoma and clear cell) were enrolled in a parallel exploratory cohort.A total of 102 patients were accrued. Amongst 36 endometrioid histology patients, response rate was 14%, 12-week PFS rate was 67% and median PFS, 4.8 mths. In serous cohort of 34 patients, response rate was 12%, 12-week PFS was 56% and median PFS 4.0 mths. In a separate cohort of 32 patients with uncommon histology EC (including carcinosarcoma), response rate was 6% and 12-wk PFS was 47%. Six patients were on treatment for > 12months, including 2 for > 30 months. Common cabozantinib-related toxicities (> 30% patients) included hypertension, fatigue, diarrhea, nausea and hand-foot syndrome. Gastrointestinal fistula/perforation occurred in 4 of 70 (6%) patients with serous/endometrioid cancer and 5 of 32 (16%) patients in exploratory cohort. We observed increased frequency of responses with somatic CTNNB1 mutation (4 PRs in 10 pts, median PFS 7.6 mths) and concurrent KRAS and PTEN/PIK3CA mutations (3 PRs in 12 patients, median PFS 5.9 mths).Cabozantinib has activity in serous and endometrioid histology EC. These results support further evaluation in genomically characterized patient cohorts.