Clinical outcomes of immune checkpoint inhibitor plus nab-paclitaxel in metastatic upper tract urothelial carcinoma

Metastatic upper tract urothelial carcinoma (mUTUC) is a malignant cancer associated with poor prognosis. Few studies have investigated the clinical outcome of a recently developed combination regimen of programmed cell death 1 (PD-1) inhibitor plus nab-paclitaxel in mUTUC.We retrospectively retrieved data from the electronic medical records of cisplatin-ineligible or cisplatin-refractory mUTUC patients from five participating Chinese centers, who received treatment of PD-1 inhibitor plus nab-paclitaxel between April 2018 and January 2022. Clinical response was assessed according to Response Evaluation Criteria in Solid Tumors criteria version 1.1 (RECIST 1.1). Duration of response (DOR), overall survival (OS), and progression-free survival (PFS) were evaluated by the Kaplan-Meier method.The confirmed overall response rate (ORR) was 14/34 (41.2%), and the disease control rate (DCR) was 24/34 (70.6%). Complete response (CR) was achieved in one case, partial response (PR) in 13 cases (38.2%), stable disease (SD) in 10 cases (29.4%), and progressive disease (PD) occurred in 10 cases (29.4%). After a median follow-up period of 16.0 months [95% confidence interval (CI): 9.9-22.1], 14 deaths were reported, with a median OS of 15.0 months (95% CI: 9.9-20.1); 22 progressions were reported, with a median PFS of 6.0 months (95% CI: 2.4-9.6). Patients with visceral metastasis had a similar PFS [hazard ratio (HR): 1.28, 95% CI: 0.53-3.09, P=0.574) and OS (HR: 1.94, 95% CI: 0.64-5.83, P=0.279] to patients with lymph node metastasis only.This real-world study suggests that PD-1 inhibitor plus nab-paclitaxel is effective in cisplatin-ineligible and cisplatin-refractory mUTUC patients with acceptable toxicity, especially for patients with visceral metastasis.