Camrelizumab Plus Nab-paclitaxel in Patients with Previously Treated Advanced Urothelial Carcinoma: A Multicenter...

Background: 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. Methods: 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/m² 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. Results: 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. Conclusions: Camrelizumab plus nab-paclitaxel demonstrated modest antitumor activity along with manageable toxicity in patients with previously treated aUC. Trial registration: This trial was registered at www.chictr.org.cn (Identifier: CTR2000033820, registration date: 2020 June 13).