218P - Clinical effectiveness of tislelizumab combined with gemcitabine/cisplatin (GC) versus GC as adjuvant therapy in high-risk muscle-invasive urothelial carcinoma (MIUC): A real-world study

Background

Adjuvant chemotherapy improved disease-free survival (DFS) among MIUC patients (pts). CheckMate 274 study demonstrated adjuvant immunotherapy improved DFS in MIUC pts. However, few studies explored the efficacy of adjuvant chemotherapy plus immunotherapy in MIUC pts. Our real-world study aimed to evaluate the effectiveness of adjuvant chemoimmunotherapy versus chemotherapy in high-risk MIUC pts.

Methods

Clinical data of high-risk MIUC pts between October 2016 and March 2023 were retrospectively collected from Sun Yat-sen University Cancer Center. After radical surgery, pT3/4 and pN+ MIUC pts without prior neoadjuvant therapy received adjuvant tislelizumab combined with GC (T+GC) or GC. In T+GC group, pts firstly received cisplatin 70 mg/m² D2, and gemcitabine 1000 mg/m² D1 and D8 every 3 weeks for 2-6 cycles, then received tislelizumab 200 mg every 3 weeks for 2-17 cycles. In GC group, pts received cisplatin 70 mg/m² D2, and gemcitabine 1000 mg/m² D1 and D8 every 3 weeks for 2-6 cycles. The primary outcome was DFS, and secondary outcomes were OS and safety.

Results

The median follow-up was 17.7(2.1-38.3) months, totally 117 MIUC pts were analyzed, with a median age of 64 (34-85) years. 75.2% were male, 46.2% were UTUC, 20.5% were variant histology; pT3=58.9%, pT4=17.1%; pN+=52.1%. In T+GC group (n=68), the mean number of tislelizumab cycles was 4 and GC cycles was 2.7. In GC group (n=49), the mean number of GC cycles was 2.9. The T+GC group (n=68) had a significantly longer DFS compared with the GC group (n=49) (median DFS (95% CI): 19.1 (6.0-32.5) vs 8.4 (1.0-39.4) months, HR=0.172, P<0.001). While lymphovascular invasion pts had a lower probability of DFS (HR=22.1 (2.8-173.5), P=0.003). The OS was longer in the T+GC group (n=68) (median OS (95% CI): 20.1(6.0-32.5) vs 12.2(1.5-39.4) months, P=0.186). Longer follow-up was required to determine the OS benefits in T+GC group. Grade 1-2 immune related adverse events including pruritus (n=10), ALT/AST increased (n=8), hyperthyroidism (n=5) and hyperglycaemia (n=3).

Conclusions

Our data demonstrated effectiveness of tislelizumab combined with GC as adjuvant therapy for pT3/4 and pN+ MIUC pts in real world.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Sun Yat-sen University Cancer Center.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.