Background: In CheckMate 9ER, NIVO+CABO improved or maintained HRQoL vs SUN in previously untreated aRCC. We report an exploratory analysis of HRQoL in International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk-based subgroups treated with NIVO+CABO vs SUN in CheckMate 9ER (minimum follow-up, 36.5 mo). Methods: Subgroups were stratified by IMDC categories of favorable (F) risk (score = 0) or intermediate/poor (I/P) risk (score = 1–6) at randomization. HRQoL was evaluated using Functional Assessment of Cancer Therapy–Kidney Symptom Index (FKSI-19). Changes from baseline (BL) through wk 151 were analyzed using mixed-model repeated measures (MMRM). Bother due to treatment side effects (FKSI-19 item GP5) was assessed using a generalized estimating equations model (response dichotomized as minimal [“not at all” or “a little bit”] vs notable [“somewhat,”“quite a bit,” or “very much”]). Cox proportional hazards (CPH) modeling was used to evaluate time to confirmed deterioration (TTCD). Results: Differences in least square means (LSM) for FKSI-19 scores through wk 151 indicated HRQoL benefit in the NIVO+CABO arm over the SUN arm for I/P-risk patients (n = 505) but not for F-risk patients (n = 146). In the I/P-risk subgroup, longitudinal analysis of FKSI-19 total scores indicated that HRQoL improved through wk 151 in the NIVO+CABO arm but decreased from BL in the SUN arm. HRQoL declined from BL through wk 151 in F-risk patients in the NIVO+CABO and SUN arms. Patients were less likely to be bothered by side effects of NIVO+CABO vs SUN regardless of risk (I/P-risk odds ratio [OR], 0.50; 95% CI, 0.34–0.75; F-risk OR, 0.51; 95% CI, 0.28–0.91). TTCD analysis of FKSI-19 scores of the I/P-risk subgroup indicated that the NIVO+CABO arm had lower deterioration risk than the SUN arm. For the F-risk subgroup, risk based on FKSI-19 total scores was similar for both treatment arms. Conclusions: Compared with SUN, NIVO+CABO improved or maintained HRQoL in I/P-risk patients and had less side effect bother in all subgroups. There were no significant differences between treatment arms for F-risk patients. Clinical trial information: NCT03141177.

^aThrough wk 151. ^bPositive value favors NIVO+CABO over SUN; negative value indicates deterioration.