The new world of poly-(ADP)-ribose polymerase inhibitors (PARPi) used in the treatment of gynecological cancers.

The clinical development of poly-(ADP)-ribose polymerase inhibitors (PARPi) began with the treatment of ovarian cancer patients harboring BRCA1/2 mutations and continues to be expanded to other gynecological cancers. Furthermore, The Cancer Genome Atlas (TCGA) analysis of endometrial and cervical cancers offered rationale that PARPi may be an option for treatment based on the molecular profiles of these cancer types. This review summarizes the current indications of PARPi, such as its role in the treatment and maintenance of recurrent ovarian cancer and for first-line maintenance therapy in advanced ovarian cancer. We also outline new concepts for PARPi therapy in other gynecological cancers such as endometrial and cervical cancers based on recent clinical data. Finally, we present potential future directions to continue exploring the world of PARPi resistance and combining PARPi with other therapies.

Discrepancy in calculated and measured glomerular filtration rates in patients treated with PARP inhibitors.

OBJECTIVE: To describe discrepancies in calculated and measured glomerular filtration rate in patients using PARP (poly ADP ribose polymerase) inhibitors who had an elevation in serum creatinine levels. METHODS: Retrospective cohort, single center study. Patients included were those with ovarian or endometrial cancer taking olaparib, rucaparib or niraparib, and in in whom an increased serum creatinine was identified. The study cohort included those who also underwent technetium-99m radioisotope renography (glomerular filtration rate (GFR) scan). The main objective is to describe the discrepancies in calculated glomerular filtration rate using the Cockcroft-Gault method and measured glomerular filtration rate using a GFR scan. RESULTS: 211 patients were included in the study; 64 (30%) had on-treatment elevated serum creatinine, and 23 (36%) underwent a GFR scan. 32 GFR scans were performed (six patients had more than one scan). Using a clinical cut-off ≥50 mL/min as normal renal function, both calculated and estimated glomerular filtration rates were below normal in 6 of 32 GFR scans. In those patients undergoing a GFR scan, serum creatinine had risen a median 49% (IQR 20-66%, range 0-144%) above baseline. Discordance between a calculated low glomerular filtration rate and an estimated normal glomerular filtration rate occurred in 63% (range of glomerular filtration rate discrepancy: -46% to +237%). Despite increases in serum creatinine on therapy and a subsequent significant decline in the per patient calculated creatinine clearance (mean 65.6 mL/min vs 43.4 mL/min; p<0.0001), the estimated glomerular filtration rate from the renal scan was nearly identical to the patient's baseline (65.6 mL/min vs 66.1 mL/min; p=0.89). CONCLUSIONS: Serum creatinine elevation in patients taking PARP inhibitors may not be associated with a true decrease in glomerular filtration rate. A high index of suspicion should be maintained for alternative causes of elevated serum creatinine in patients treated with PARP inhibitors who lack other sources of renal injury.

Response to pembrolizumab in a heavily treated patient with metastatic ovarian carcinosarcoma.

BACKGROUND: Ovarian carcinosarcoma is a rare malignancy associated with a high rate of cancer-related mortality even at early stages. Guidelines for systemic treatment have been difficult to establish because the disease is commonly excluded from prospective clinical trials. Ovarian carcinosarcoma is usually managed as high-grade epithelial ovarian cancer despite major histologic differences. Owing to the rarity and poor prognosis of ovarian carcinosarcoma, salvage treatments and their efficacy have been poorly described. CASE PRESENTATION: A patient heavily treated for ovarian carcinosarcoma showed an objective response to an immune checkpoint inhibitor, pembrolizumab. Pembrolizumab in this patient appeared to provide tumor control in multifocal metastatic sites. CONCLUSIONS: Pembrolizumab should be evaluated in prospective trials for the treatment of ovarian carcinosarcoma and further work is needed to identify patients most likely to respond to this type of intervention.