Treatment-free survival (TFS) could help capture additional perspective about the patient experience during treatment with immune checkpoint inhibitor (ICI) therapy, thus complementing the commonly used end points of overall survival (OS) and progression-free survival (PFS). The study details were reported in the Journal of Clinical Oncology.
Data were pooled from the phase 3 CheckMate 067 clinical trial (ClinicalTrials.gov Identifier: NCT01844505) and phase 2 CheckMate 069 clinical trial (ClinicalTrials.gov Identifier: NCT01927419). The trials evaluated nivolumab and ipilimumab in combination or as single agents for the treatment of advanced melanoma. Between the 2 trials, 1087 patients were enrolled and 1077 were included in the pooled analysis.
TFS was defined as the area between Kaplan-Meier curves for 2 “fundamental” time-to-event end points. The 2 end points were time to ICI protocol therapy cessation and time to subsequent therapy initiation.
Overall, among the 1077 patients, 999 stopped ICI therapy, 499 began an additional line of systemic therapy, and 563 died. Patients who received nivolumab plus ipilimumab had a longer restricted mean TFS than patients who received single-agent nivolumab or ipilimumab (11.1 months vs 4.6 months or 8.7 months, respectively). In addition, patients who received nivolumab plus ipilimumab had a longer TFS without toxicity than patients who received single-agent nivolumab (difference, 6.0 months) or ipilimumab (difference, 1.7 months).
“In conclusion, in addition to the conventional end points of PFS and OS, clinical trials that involve immuno-oncology agents should estimate and compare TFS with and without toxicity between different therapeutic strategies to capture patient experiences more completely,” the study authors wrote.
Regan MM, Werner L, Rao S, et al. Treatment-free survival: A novel outcome measure of the effects of immune checkpoint inhibition-a pooled analysis of patients with advanced melanoma [published online September 9, 2019]. J Clin Oncol. doi: 10.1200/JCO.19.00345