Nivolumab adjuvant to chemo-radiation in localized muscle-invasive urothelial cancer: primary analysis of a multicenter, single-arm, phase II, investigator-initiated trial (NEXT).

BACKGROUND

Muscle-invasive urothelial cancer (UC) has a high risk of recurrence after definitive treatment. Nivolumab adjuvant to radical surgery improves disease-free survival in patients with UC with a high risk of recurrence; however, its role adjuvant to chemoradiation therapy (CRT) is unknown.

METHODS

The NEXT trial is a single-arm, phase-2 study evaluating the efficacy and tolerability of nivolumab adjuvant to CRT in patients with localized or locoregional UC. The primary endpoint is failure-free survival (FFS) at 2 years. Secondary endpoints include patterns of recurrence, toxicity and quality of life (QoL). Plasma cell-free DNA (cfDNA) was subjected to shallow whole-genome sequencing to correlate with outcomes.

RESULTS

28 patients were enrolled and received 480 mg of nivolumab intravenously every 4 weeks for up to 12 cycles adjuvant to CRT. The FFS at 2 years was 33.2% (95% CI 18.5% to 59.6%). Nine (32%) patients had localized progression, and eight (29%) had distant progression. 25 (89%) had one or more high-risk features (ie, plasmacytoid differentiation, T4, N+, multiple tumors, tumors >5 cm, residual disease before CRT, carcinoma in situ, and hydronephrosis). Patients with ≤2 high-risk features had a median FFS of 45.2 months (95% CI 14.56 to not reached (NR)) compared with 8.2 months (95% CI 7.1 to NR) in those with three or more risk features (p=0.0024). Nivolumab-associated treatment-related adverse events occurred in 18 (64.3%) patients, only 3 had grade 3 TRAEs, with significant changes in QoL. Plasma cfDNA copy number instability (CNI) scores ≤25 before the first dose of adjuvant nivolumab and at cycle 4 were associated with better overall survival compared with CNI scores ≥26 (49.6 months vs 20.5 months, p=0.0024). Genome copy number changes indicated chromatin remodeling and tyrosine kinase pathways, among others, as oncogenic drivers implicated in progression.

CONCLUSION

Nivolumab adjuvant to CRT in localized or locally advanced UC is well tolerated. Stratification by risk factors and correlation with plasma cfDNA analyses generate hypotheses for potential patient selection and putative therapeutic targets for future study.

TRIAL REGISTRATION NUMBER: NCT03171025.