OBJECTIVES:  The aim was to update previous analyses of predictors of health-related quality of life over time to estimate utilities for patients with treatment-naive advanced melanoma using the 28-month data cut from the randomized CheckMate 067 trial comparing nivolumab + ipilimumab, nivolumab monotherapy, and ipilimumab monotherapy for use in a cost-effectiveness model (CEM). METHODS:  The EQ-5D was administered at baseline and every 6 weeks in CheckMate 067 and was used to generate index utility scores using the UK time trade-off method. Covariates were based on a combination of prior analyses of large trial data sets, including patient demographic and clinical characteristics, quantitative metrics of fit, qualitative/clinical plausibility, and relevance to the CEM. Several longitudinal mixed linear models were explored using different covariate sets. RESULTS:  This analysis included 916 patients and 7735 visits where the EQ-5D was administered. Mean baseline utility score was 0.774 for nivolumab + ipilimumab patients, 0.779 for nivolumab patients, 0.773 for ipilimumab patients, and 0.775 across all patients. The final model selected included baseline utility (to adjust for imbalance between treatment arms), progression status (pre/post), and treatment arm. Parameter estimates in the model were 0.418 for baseline utility (p<0.001), -0.035 for progression status (p<0.001), and -0.028 (p=0.042) and -0.026 (p=0.064) for ipilimumab and nivolumab + ipilimumab (vs. nivolumab), respectively. Additional models including time before death or end of follow-up were tested, but the selected model was found to be a better fit to the data. When implemented in the CEM, the utility estimates for the preprogression and postprogression states were 0.792 and 0.758, respectively (applying nivolumab as the reference treatment arm). CONCLUSIONS:  Results showed that baseline utility, progression, and treatment were predictors of utility over time, which is consistent with prior analyses of this trial as well as other nivolumab monotherapy and ipilimumab monotherapy trials.