Window of Opportunity Pilot Study of Pembrolizumab in Obesity-driven Endometrial Cancer

Study Summary

Programmed cell death 1 (PD-1) inhibitor treatment may benefit patients with endometrial cancer (EC) based on the following observations: 1) an overwhelming presence of PD-1 in ECs; 2) the well-known effect of obesity which activates pro-inflammatory white blood cells and promotes the development of ECs; and 3) the high prevalence of a specific gene pattern (ie, microsatellite instability hypermutated \[MSI high\]) among ECs that may be particularly sensitive to this class of drugs. To identify potential biomarkers of response to PD-1 inhibitors in EC, we will conduct a window of opportunity study of pembrolizumab in 20 patients with clinical stage 1, grade 3 EC, encompassing endometrioid, serous and clear cell histologies. Eligible patients will undergo a research biopsy for collection of fresh tissue at the time of enrollment, in addition to the routinely performed endometrial biopsy that led to the diagnosis of their cancer. Patients will receive a single dose of pembrolizumab (200 mg IV) prior to undergoing their scheduled hysterectomy with surgical staging three weeks later. As per standard of care, adjuvant chemotherapy with paclitaxel and carboplatin will be recommended after hysterectomy/surgical staging for women with endometrioid tumors and stage III disease or women with serous/clear cell tumors at all stages of disease. However, in this study pembrolizumab will be added to adjuvant paclitaxel and carboplatin for EC. Pre-treatment endometrial biopsy specimens (fresh frozen tissue and formalin-fixed paraffin embedded (FFPE)) and a post-treatment hysterectomy specimen (fresh frozen tissue and FFPE) will be collected for translational studies. Blood, fecal and vaginal samples will be collected pre-treatment, at the time of surgery and following 3 cycles of adjuvant pembrolizumab/paclitaxel/carboplatin treatment.

Interventions

• DRUG Pembrolizumab
• PROCEDURE Hysterectomy