Tislelizumab in combination with gemcitabine plus cisplatin chemotherapy as first-line adjuvant treatment for locally advanced or metastatic bladder cancer: a retrospective study

BACKGROUND: Combining immune checkpoint inhibitors with chemotherapy can synergistically improve antitumor activity and are generally well tolerated. Recently, the efficacy and safety of combination therapy has been demonstrated for many cancers, including urothelial carcinomas. The aim of this retrospective pilot study was to evaluate the efficacy and safety of tislelizumab plus chemotherapy as first-line adjuvant treatment for locally advanced or metastatic bladder cancer. METHODS: We conducted a retrospective analysis of 31 patients with locally advanced or metastatic bladder cancer from December 2020 to January 2022 with an Eastern Cooperative Oncology Group performance status of 0/1. Of the 31 patients, 14 patients received tislelizumab (200 mg i.v. every 3 weeks, Q3W) plus 21 days cycles of chemotherapy (gemcitabine, 1000 mg/m(2) i.v. on days 1 and 8 of each cycle + cisplatin, 70 mg/m(2) i.v. on day 2 of each cycle) (TGC) treatment and 17 patients received gemcitabine plus cisplatin chemotherapy (GC) treatment. All patients treated with bladder cytoreductive surgery and were treated for four 21 days cycles until disease progression or intolerable treatment-related adverse events (TRAEs). The objective progression-free survival (PFS), overall survival (OS), overall response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR) and TRAEs were recorded and reviewed. RESULTS: As of the cut-off date (March 25, 2022), PFS, OS, ORR, DCR, CBR and TRAEs were evaluated in 14 patients receiving combination therapy and 17 patients in the chemotherapy alone group. The median PFS was 36.0 [95% confidence interval (CI) 33.1–38.9] weeks in the TGC group and 29.0 (95% CI 25.4–32.6) weeks in the GC group [hazard ratio (HR) 0.15 (95% CI 0.04–0.55)]. In the GC group, the median OS was 48.0 (95% CI 39.7–56.3) weeks; the median OS was not yet mature for the TGC group [HR 0.26 (95% CI 0.07–0.94)]. Treatment with TGC resulted in improved DCR (TGC 71.4%; GC 65.0%) and CBR (TGC 64.3%; GC 52.9%) compared with GC. However, although higher incidences of grade ≥ 3 TRAEs were observed with TGC compared with GC (35.7% vs 23.5%), the difference was not statistically significant (p = 0.47). CONCLUSION: This study suggested that TGC provided survivors of locally advanced or metastatic bladder cancer with encouraging antitumor activity and was generally well tolerated.