Study details
KEYNOTE-564 involved 996 patients with clear-cell RCC at high risk for recurrence after nephrectomy, with or without metastasectomy. They were randomly assigned in a 1:1 ratio to receive a 200-mg dose of adjuvant pembrolizumab or placebo given intravenously once every 3 weeks for up to 17 cycles for approximately 1 year.
The vast majority of patients enrolled in the study had localized disease with no evidence of metastases (M0) and intermediate to high or high risk of disease recurrence after partial or complete nephrectomy. However, 5.8% of patients in both the pembrolizumab and placebo groups had M1 NED (metastatic stage 1, no evidence of disease) status after nephrectomy and resection of metastatic lesions. These patients were also at intermediate to high or high risk of recurrence.
The benefit of pembrolizumab, compared with placebo, was maintained in this subgroup, said the investigators. “At this point, we continue to look at the data, but we know that there was a benefit for DFS in the population we included,” said Dr. Choueiri. “When we looked at several subgroups such as PD-L1 status, geography, gender, performance status, M0/M1, all HRs were less than 1 suggesting benefit from pembrolizumab over placebo.”
“Subset analyses by stage are going to be important to determine which group of patients will derive the most benefit,” asserted Dr. McKay. “While those with M1 NED appear to derive benefit with HR for DFS of 0.29, those with M1 NED comprise a small percentage of patient enrolled in the trial.”
Studies exploring tissue- and blood-based biomarkers, including circulating tumor DNA, will be key to identify patients at highest risk for recurrence or adjuvant treatment, Dr. McKay emphasized. “The adoption of adjuvant immune checkpoint inhibitors brings along new questions regarding patient selection, therapeutic use in patients with non–clear-cell renal cell carcinoma, and systemic treatment after recurrence during or after the receipt of adjuvant therapy.”
KEYNOTE-564 was funded by Merck. Multiple study authors including Dr. Choueiri have financial ties to the pharmaceutical industry, including Merck.
A version of this article first appeared on Medscape.com.