Camrelizumab plus nab-paclitaxel showed modest activity in previously treated advanced urothelial carcinoma patients.

Immune checkpoint inhibitor (ICI) plus nab-paclitaxel has emerged as a promising strategy for advanced urothelial carcinoma (aUC). This study investigates the efficacy and safety of camrelizumab combined with nab-paclitaxel in patients with aUC who had progressed following first-line treatment. This multicenter, phase II study enrolled patients with aUC who had previously received at least 1 platinum-based therapy. Patients with prior ICI-based therapies were also included. Participants received 200 mg of camrelizumab on day 1 (D1) and 125 mg/m of nab-paclitaxel on D1 and D8, on a 21-d cycle, until disease progression or unacceptable toxicity. The primary end point was progression-free survival (PFS). Potential biomarkers were identified through targeted gene sequencing and by quantifying pretreatment serum levels of cytokines, chemokines, growth factors, and other soluble proteins. From 2020 June 12 to 2024 April 1, a total of 60 eligible patients were enrolled. The median age was 62.5 years, 44 patients (73.33%) were male, 44 patients (73.33%) had upper tract urothelial carcinoma, and 17 patients (28.33%) received ICI-based therapies before recruitment. After a median follow-up of 27.50 months (95% confidence interval [CI], 21.90-not reached [NR]), 47 patients (78.33%) experienced disease progression. The median PFS and overall survival were 4.66 months (95% CI, 4.13 to 8.50 months) and 15.70 months (95% CI, 12.17-NR) in the full analysis set, respectively. In addition, the median PFS and overall survival were 6.45 (95% CI, 4.30 to 9.98) months and 17.98 (95% CI, 15.44-NR) months in the per-protocol set, respectively. The objective response rate was 37.04%, with 4 patients achieving complete responses and 16 patients achieving partial responses. Notably, 15 patients experienced durable responses lasting over 1 year. Adverse events of any grade occurred in 59 patients (98.33%), while grade ≥3 adverse events were reported in 31 patients (51.67%). One patient experienced immune-related pneumonia. Biomarker analyses suggested that the elevated pretreatment serum levels of cluster of differentiation 25, interleukin-6, and insulin-like growth factor binding protein 2 were associated with worse treatment responses. Camrelizumab plus nab-paclitaxel demonstrated modest antitumor activity along with manageable toxicity in patients with previously treated aUC. This trial was registered at www.chictr.org.cn (Identifier: CTR2000033820, registration date: 2020 June 13).