Niraparib is a FDA approved Poly(ADP-ribose) polymerase inhibitor (PARPi) for the treatment of platinum-sensitive ovarian serous carcinoma. The safety profile of niraparib was established in phase III clinical trials. The therapeutic effect of niraparib on serous endometrial carcinoma is now being investigated in several clinical trials. However, the antineoplastic effect and the safety profile of niraparib in chemotherapy naïve high-grade endometrial cancer patients is unknown. By employing a phase 0 exploratory trial design, the investigators will study the niraparib's effect on endometrial cancer in chemotherapy naïve patients using molecular biomarkers as sentinels for the antineoplastic effect. Women diagnosed by endometrial biopsy with high-grade endometrial cancer will receive niraparib for 28 days. Staging surgery will be performed 4-6 weeks after the diagnosis (standard of care). The investigators will use the pre-operative biopsy and the surgical specimen to perform comparative multidimensional analysis of endometrial tumors before and after exposure to niraparib.
The study will investigate the effect of niraparib on tumor tissue in chemotherapy naïve, newly diagnosed, high-grade endometrial cancer patients. Biomarkers of cognate molecular pathways as well as investigational assays will be used to study the antineoplastic effect of the drug.