RT Journal Article SR Electronic T1 Translational randomized phase II trial of cabozantinib in combination with nivolumab in advanced, recurrent, or metastatic endometrial cancer JF Journal for ImmunoTherapy of Cancer JO J Immunother Cancer FD BMJ Publishing Group Ltd SP e004233 DO 10.1136/jitc-2021-004233 VO 10 IS 3 A1 Stephanie Lheureux A1 Daniela E Matei A1 Panagiotis A Konstantinopoulos A1 Ben X Wang A1 Ramy Gadalla A1 Matthew S Block A1 Andrea Jewell A1 Stephanie L Gaillard A1 Michael McHale A1 Carolyn McCourt A1 Sarah Temkin A1 Eugenia Girda A1 Floor J Backes A1 Theresa L Werner A1 Linda Duska A1 Siobhan Kehoe A1 Ilaria Colombo A1 Lisa Wang A1 Xuan Li A1 Rachel Wildman A1 Shirin Soleimani A1 Scott Lien A1 John Wright A1 Trevor Pugh A1 Pamela S Ohashi A1 David G Brooks A1 Gini F Fleming YR 2022 UL http://jitc.bmj.com/content/10/3/e004233.abstract AB Background Combining immunotherapy and antiangiogenic agents is a promising treatment strategy in endometrial cancer. To date, no biomarkers for response have been identified and data on post-immunotherapy progression are lacking. We explored the combination of a checkpoint inhibitor (nivolumab) and an antiangiogenic agent (cabozantinib) in immunotherapy-naïve endometrial cancer and in patients whose disease progressed on previous immunotherapy with baseline biopsy for immune profiling.Patients and methods In this phase II trial (ClinicalTrials.gov NCT03367741, registered December 11, 2017), women with recurrent endometrial cancer were randomized 2:1 to nivolumab with cabozantinib (Arm A) or nivolumab alone (Arm B). The primary endpoint was Response Evaluation Criteria in Solid Tumors-defined progression-free survival (PFS). Patients with carcinosarcoma or prior immune checkpoint inhibitor received combination treatment (Arm C). Baseline biopsy and serial peripheral blood mononuclear cell (PBMC) samples were analyzed and associations between patient outcome and immune data from cytometry by time of flight (CyTOF) and PBMCs were explored.Results Median PFS was 5.3 (90% CI 3.5 to 9.2) months in Arm A (n=36) and 1.9 (90% CI 1.6 to 3.4) months in Arm B (n=18) (HR=0.59, 90% CI 0.35 to 0.98; log-rank p=0.09, meeting the prespecified statistical significance criteria). The most common treatment-related adverse events in Arm A were diarrhea (50%) and elevated liver enzymes (aspartate aminotransferase 47%, alanine aminotransferase 42%). In-depth baseline CyTOF analysis across treatment arms (n=40) identified 35 immune-cell subsets. Among immunotherapy-pretreated patients in Arm C, non-progressors had significantly higher proportions of activated tissue-resident (CD103+CD69+) ɣδ T cells than progressors (adjusted p=0.009).Conclusions Adding cabozantinib to nivolumab significantly improved outcomes in heavily pretreated endometrial cancer. A subgroup of immunotherapy-pretreated patients identified by baseline immune profile and potentially benefiting from combination with antiangiogenics requires further investigation.All data relevant to the study are included in the article or uploaded as supplementary information.