Background ProNiHN is a prospective, observational, and multicenter study of patients (pts) with R/M SCCHN treated with nivo after progressing on or after platinum-based therapy. We report here the effectiveness and QoL for pts and their caregivers (cg). Methods Based on a minimum follow-up of 17-months (mo), progression-free survival (PFS) and overall survival (OS) were estimated with Kaplan-Meier method. QoL changes of pts were measured with 3 questionnaires (FACT-H&N & EQ-5D-3L&VAS) between inclusion (incl) and week-6, mo-3, 6, 12 and 18. QoL and needs of cg were estimated with CarGOQoL and SCNS-P&C-F questionnaires at incl and at 6 mo. Results Among 487 patients, median PFS and OS were 3.3 mo and 9.3 mo, respectively. OS rates were 64% at 6 mo, 40% at 12 mo and 28% at 18 mo. The number of pts completing FACT-H&N was 354 at incl and decreased to 39 at 18 mo. QoL of overall population tended to be stable or improved over time (Table). Same trend was observed for EQ-5D-3L&VAS. For pts (n=121) who completed FACT-H&N both at incl and 6 mo, overall total score significantly decreased (mean: -4.7; p=0.003), in particular for pts who stopped nivo within the 6 mo (-8.8; p<0.001) whereas it remained stable (0.0; p=0.986) for pts still on nivo. No significant difference was observed for pts (n=64) between incl and 12 mo (-2.4; p=0.291). 292 pts mentioned a cg, mostly spouse (71.4%). Among them, 48 cg completed CarGOQoL at incl and 6 mo. Psychological well-being improved over time (43.8 vs. 52.0; p=0.027) while relationship with healthcare decreased (62.0 vs. 53.1; p=0.045). FACT-H&N and CarGOQoL results were correlated at incl (0.226, p=0.003) and at 6 mo (0.362; p=0.006). Conclusions Nivo showed similar effectiveness and QoL in the real-world as in pivotal trial. QoL of pts tended to be stabilized over time, especially for patients still treated with nivolumab at 6 mo. QoL of cg and pts seems to be correlated.Read less <