New Outcome Measure Posited for Immunotherapy in Advanced Melanoma
Posted: Wednesday, October 2, 2019
A novel statistical measurement—treatment-free survival—described in the Journal of Clinical Oncology may help to capture the experience of patients participating in trials of immune checkpoint inhibitor (ICI) therapies. “The conventional endpoints of progression-free survival and overall survival…may not provide a comprehensive assessment of the unique outcomes seen with ICIs,” stated the authors. Specifically, patients who discontinue immunotherapy may experience periods of remission or durable disease control without needing subsequent systemic therapy—as well as persistent treatment-related adverse events. “We propose that the analysis of treatment-free survival could be part of the future reporting of clinical trials that involve immuno-oncology agents compared with one another as well as compared with chemotherapeutic and targeted therapies.”
“Treatment-free survival is the area between the two Kaplan-Meier curves for time to cessation of ICI protocol therapy and time to subsequent systemic anticancer therapy initiation or death (analogous to time to treatment failure and time to second-line therapy, respectively),” wrote Meredith M. Regan, ScD, of Dana-Farber Cancer Institute in Boston, and colleagues. To model treatment-free survival, they pooled data from 1,087 patients enrolled in the CheckMate 067 and 069 trials of nivolumab and ipilimumab used in combination and as monotherapies for previously untreated advanced melanoma.
Treatment-free survival was partitioned as the time with and without toxicity by a third endpoint, time to cessation of both ICI therapy and toxicity, explained Dr. Regan and her team. Toxicity was defined as both persistent and late-onset grade 3 or higher treatment-related adverse events. At 36 months, 47% of the patients who initiated nivolumab plus ipilimumab, 37% who initiated nivolumab, and 15% who initiated ipilimumab were surviving free of subsequent therapy initiation. “The restricted mean treatment-free survival was longer with nivolumab plus ipilimumab (11.1 months) than with nivolumab (4.6 months) or ipilimumab (8.7 months),” stated the authors. “Restricted mean treatment-free survival represented 31% (3% with and 28% without toxicity), 13% (1% and 11%), and 24% (less than 1% and 23%) of the 36-month period, respectively, in the three treatment groups. Treatment-free survival without toxicity was longer for nivolumab plus ipilimumab than for nivolumab (difference, 6.0 months) or ipilimumab (difference, 1.7 months).”
Disclosure: The study authors’ disclosure information may be found at ascopubs.org