Phase II clinical study of tislelizumab combined with nab-paclitaxel (TRUCE-01) for muscle-invasive urothelial bladder carcinoma: Bladder preservation subgroup analysis.

Abstract

4589 Background: The current strategy for bladder preservation is focused on trimodality treatment, including complete transurethral resection of bladder tumor (cTURBT), with concurrent chemotherapy and radiotherapy. Chemotherapy is usually a cisplatin-based regimen. However, many pts cannot tolerate cisplatin-based chemotherapy and radiation therapy. It fails to meet clinical needs. Meanwhile, the efficacy and safety of checkpoint inhibitors (ICIs) have now been demonstrated. We conduct a study to evaluate ICIs in combination with second-line chemotherapy agents for patients with MIBC. Methods: TRUCE-01 is a phase II trial (NCT04730219) of tislelizumab combined with nab-paclitaxel before cTURBT or radical cystectomy. Pts with pure or mixed urothelial bladder cancer (T2-4a Nx M0) received tislelizumab 200mg on days 1 plus paclitaxel 200mg on days 2 every 3 weeks (Q3W) x 3 cycles followed by cTURBT or radical cystectomy. Imaging evaluation is usually done before and after the drug administration using the same tests to assess the efficacy. Pts who choose to preserve bladder usually continue their medication after cTURBT. This abstract focuses on patients with bladder preservation. Results: Between July 2020 and November 2021, 47 pts completed at least 2 cycles of treatment, 22 (47%) pts received cTURBT, 16 (34%) pts received radical cystectomy and 9 (19%) pts refuse surgery. As for radiological response, 22 achieved complete response (CR), 16 achieved partial response (PR). In the bladder-preserving subgroup, 13 CR pts and 9 PR pts selected cTURBT, pathology showed 17 pT0, 1 pTa, 3 pT1 and 1 pTis. The median medication cycle is 9 (6-11). There were 3 pts experienced grade 3-4 adverse events (CTCAE), a grade 3 rash, a grade 3 gastric perforation and a grade 4 acute renal failure. In addition, The most common grade 1-2 adverse events include alopecia (86%), fatigue (77%), rash (41%), appetite decreases (41%), hyperglycemia (36%), fever (18%), and creatinine increased (14%). Median follow-up 357 (438-291) days with 3 recurrences and 1 death. The 1-year recurrence-free survival rate was 82%. Conclusions: The early efficacy data further support the role of tislelizumab combined with paclitaxel in bladder preservation setting with an acceptable adverse events. Patients with imaging CR or PR after neoadjuvant therapy are preferred for bladder preservation. Enrollment is ongoing. Clinical trial information: NCT04730219.