In previously treated patients with metastatic urothelial carcinoma (mUC), chemotherapy efficacy is poor and associated with significant toxicity, Dr. Sharma said. Monotherapy trials (phase 1/2 and 2) of nivolumab have shown notable antitumor activity in patients previously treated for mUC, with overall response rates (ORR) of 19.6% and median overall survival (OS) of 8.7 months. Both preclinical and clinical data with the combination of nivolumab, a programmed cell death-1 blockade, and ipilimumab (Yervoy, Bristol-Myers Squibb), a cytotoxic T-lymphocyte–associated antigen-4 blockade, have shown improved antitumor activity in advanced melanoma, non–small-cell lung cancer, and metastatic renal cell carcinoma.
Dr. Sharma presented first results from Checkmate 032, the first trial of combination immunotherapy in mUC. The phase 1/2 study compared two dosing strategies of nivolumab combined with ipilimumab in patients with previously treated metastatic disease. Twenty-eight patients received nivolumab 1 mg/kg plus ipilimumab 3 mg/kg (intravenously [IV] every three weeks for four cycles) and 104 patients received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg (IV every three weeks for four cycles), with all receiving maintenance with nivolumab 3 mg/kg IV every two weeks. The primary endpoint was investigator-assessed confirmed ORR.
Median age was greater in patients in the nivolumab 1-mg/ipilimumab 3-mg group (50.0% versus 45.2% were 65 years of age or older). Both groups had approximately 60% of patients treated with two or more prior regimens. Programmed death ligand-1 expression was higher than 1% in more patients in the nivolumab 1-mg/ipilimumab 3-mg group (38.5% versus 28.8%).
More patients are continuing treatment in the nivolumab 1-mg/ipilimumab 3-mg group (46.2% versus 14.4%). Also in that group, discontinuation for disease progression was lower (38.5% versus 64.4%). Elevation of alanine aminotransferase and aspartate aminotransferase levels was greater with the higher nivolumab dose (17.3%/11.5% versus 0%/0%, respectively). Treatment discontinuation rates were 7.7% for nivolumab 1 mg/ipilimumab 3 mg and 13.5% for nivolumab 3 mg/ipilimumab 1 mg.
Dr. Sharma said, “Grade 3–4 adverse event rates were around 30% and very similar for both groups.”
“It’s very important to note the overall response rate compared to the 19% with nivolumab monotherapy reported in Lancet Oncology and the 15% rate previously reported for atezolizumab,” Dr. Sharma said, stating that confirmed ORR was 38.5% in the nivolumab 1-mg/ipilimumab 3-mg group (95% confidence interval [CI], 20.2–59.4) and 26.0% in the nivolumab 3-mg/ipilimumab 1-mg group (95% CI, 17.9–35.5). Historical controls, she added, are 10% or less.
Complete response (3.8% versus 2.9%) and partial response rates (34.6% versus 23.1%) were higher with the higher ipilimumab dose regimen. The progressive disease rate, however, was higher with the lower ipilimumab dose regimen (26.9% versus 41.3%). Median tumor change from baseline in the target lesion was −27.8% in the nivolumab 1-mg/ipilimumab 3-mg group and 0% in the nivolumab 3-mg/ipilimumab 1-mg group. While median time to response was similar for both groups (1.4 months), ongoing response rates were higher for the higher ipilimumab dose group (80% versus 70%), as were the median progression-free survival (4.3 months versus 2.6 months) and median OS rates (10.2 versus 7.3 months).
“Efficacy with nivolumab 3 mg plus ipilimumab 1 mg did not appear to differentiate from that with nivolumab monotherapy,” Dr. Sharma observed. Nivolumab monotherapy findings had been reported previously.
While the cohort size is small, she said the findings are “very promising.” Dr. Sharma noted that the nivolumab 1-mg/ipilimumab 3-mg cohort is being expanded to 92 patients.
Commenting on a question raised after her presentation regarding the possibility of using ipilimumab at 10 mg/kg, Dr. Sharma responded, “With ipilimumab 3 mg/kg you get the same T-cell activation as with ipilimumab 10 mg/kg. Our monitoring showed, however, that ipilimumab 1 mg/kg does not give you the same level of T-cell activation as with 3 mg/kg—which would not give you the same level of antitumor response.”
American Heart Association (AHA)
This year’s AHA meeting, held November 12–16 in New Orleans, attracted approximately 18,000 medical professionals from nearly 100 countries. We review below key sessions focusing on anticoagulation for peripheral artery disease and for stroke protection in atrial fibrillation, cholesterol-lowering strategies, COX-2 inhibitors, and cognitive decline.