Adjuvant nivolumab compared with platinum-based chemotherapy in bladder cancer: A real-world study.

e16563 Background: Both adjuvant platinum-based chemotherapy and nivolumab are used after radical cystectomy for high-risk bladder cancer, yet comparative real-world survival data are limited. Treatment selection and timing vary substantially outside clinical trials. We compared survival outcomes between adjuvant nivolumab and platinum-based chemotherapy initiated within similar postoperative timeframes. Methods: Using the TriNetX database (2017–2024), we identified adults with bladder cancer who underwent radical cystectomy followed by adjuvant nivolumab or platinum-based chemotherapy (gemcitabine/cisplatin or ddMVAC). Patients who underwent neoadjuvant chemotherapy were excluded. Patients were stratified by treatment type and timing of initiation after surgery ( <60 days and 60–180 days). Propensity score matching (1:1) was performed within each timing window using demographic variables, comorbidities, and prior treatment history. Overall survival (OS) and time to next treatment (TTNT) were analyzed using Kaplan–Meier methods and log-rank testing. Results: In an overall analysis restricted to initiation of adjuvant nivolumab or platinum-based chemotherapy within <60 days of cystectomy, matched cohorts included 102 patients per group. There were not enough deaths within the first year to reliably estimate 1-year OS, however 3-year OS significantly favored nivolumab (74% vs 57%; p = 0.0367). There was no significant difference in TTNT (56 days vs 42 days; p = 0.213). In the 60-180 day analysis, matched cohorts included 85 patients. Nivolumab demonstrated superior 1-year OS that was statistically significant (86% vs 71%; p = 0.0226). 3-year OS favored nivolumab, although this was not statistically significant (71% vs 62%; p = 0.583). TTNT was not statistically significant but trended in favor of nivolumab (56 vs 42 days; p = 0.0512). Conclusions: In this large real-world cohort, adjuvant nivolumab was associated with superior overall survival compared with platinum-based chemotherapy when initiated within comparable postoperative intervals after radical cystectomy. These findings support the effectiveness of adjuvant nivolumab in routine clinical practice and reinforce its role as a preferred postoperative systemic therapy in eligible patients. These results should be interpreted cautiously due to the limited sample size. Further studies incorporating a larger sample size are warranted.