Graziela Zibetti Dal Molin

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

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. 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. 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). 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.

Demcizumab combined with paclitaxel for platinum-resistant ovarian, primary peritoneal, and fallopian tube cancer: The SIERRA open-label phase Ib trial

To evaluate the safety and preliminary efficacy of demcizumab (DLL4 targeted IgG2 humanized monoclonal antibody; potent inhibitor of the Notch pathway) in combination with weekly paclitaxel in platinum-resistant epithelial ovarian cancer (EOC); and to determine the maximum tolerated dose (MTD) or maximum administered dose (MAD). We conducted a 3 + 3 dose-escalation trial in patients with recurrent, platinum-resistant EOC with RECIST v. 1.1 measurable disease and ≤4 prior chemotherapy regimens. Two dosing cohorts (2.5 mg/kg and 5 mg/kg) were targeted; however, an intermediate dose level (3.5 mg/kg) was to be evaluated if the 5 mg/kg dose was not tolerable. Demcizumab was administered on days 1 and 15 and paclitaxel, weekly on days 1, 8, and 15 for each of three 28-day cycles: the 3-cycle doublet could be repeated once if safe. Thereafter, paclitaxel was administered until unacceptable toxicity or disease progression. Nineteen patients were enrolled. No dose-limiting toxicities (DLT) were observed; however, the intermediate dose level (3.5 mg/kg) was enrolled and expanded based on emerging safety data from other trials in the demcizumab program. The MTD was not reached. The most common treatment emergent adverse events (TEAE) were diarrhea (68%), fatigue (58%), peripheral edema (53%), and nausea (53%). Pulmonary hypertension, grade 2 (n = 2) and grade 1 (n = 1), was observed. Overall response rate (ORR) was 21% (95% CI: 6-45%); clinical benefit rate (CBR) was 42% (95% CI: 20-66%). Demcizumab in combination with paclitaxel has a manageable toxicity profile and showed activity in patients with heavily pretreated platinum-resistant ovarian cancer.