INTRODUCTIONTreatment patterns for patients with bacillus Calmette-Guérin (BCG)-unresponsive high-risk non-muscle-invasive bladder cancer (NMIBC) who are ineligible for or decline radical cystectomy (RC) are inconsistently reported. We retrospectively described demographic, clinical, and treatment characteristics for these patients and assessed their clinical outcomes.PATIENTS AND METHODSMedical charts of patients with BCG-unresponsive high-risk NMIBC (carcinoma in situ [cohort A] or T1/high-grade Ta [cohort B]) who were ineligible for or declined RC documented between January 1, 2011, and December 31, 2018, at 15 academic centers were reviewed. Primary objectives were to characterize demographic, clinical, and nonsurgical treatment characteristics. Secondary objectives included assessing real-world progression-free survival (rw-PFS) from muscle-invasive/metastatic disease, rw-PFS from worsening grade or stage, real-world complete response rate (rw-CRR) in cohort A, real-world event-free survival (rw-EFS) from high-risk NMIBC in cohort B, and overall survival.RESULTSThe study included 129 patients (cohort A, n = 57; cohort B, n = 72). Median age was 72.0 years (interquartile range, 64.0-80.0). Most patients were male (72.1%) and current/former smokers (69.8%). Median follow-up was 32.1 months (interquartile range, 20.7-47.6). BCG rechallenge with or without interferon-α (63.6%) was the most commonly utilized first nonsurgical therapy, followed by intravesical mitomycin C with or without electromotive drug administration or thermochemotherapy (15.5%), and intravesical valrubicin (10.9%); among those who received BCG rechallenge alone, 54.8% later received a non-BCG therapy in ≥ 2 subsequent treatments. 36-month rate for rw-PFS from muscle-invasive/metastatic disease was 73.5%, 66.8% for rw-PFS from worsening grade/stage, and 82.5% for overall survival. In cohort A, 6-month rw-CRR was 22.2%. In cohort B, 36-month rw-EFS rate from high-risk NMIBC was 50.2%.CONCLUSIONAfter BCG-unresponsive disease, most patients with high-risk NMIBC received BCG rechallenge with or without other therapies, and > 25% experienced disease progression within the first 3 years. Effective bladder-sparing options for BCG-unresponsive NMIBC are needed.CLINICAL TRIAL REGISTRATIONN/A.