Tislelizumab combined with gemcitabine and albumin paclitaxel as preoperative therapy for patients with borderline resectable pancreatic cancer: A prospective, single-arm, phase II trial.

4162 Background: Pancreatic cancer is a highly aggressive disease with low resection rate and poor prognosis. Neoadjuvant treatment for borderline resectable pancreatic cancer (BRPC) is increasing in acceptability, but no standard treatment has been established. Herein, we aimed to assess the safety and efficacy of a new mode of preoperative therapy for patients with BRPC. Methods: This is a single arm, exploratory phase II clinical trial. Gemcitabine (1000 mg/m 2 ) and albumin paclitaxel (125 mg/m 2 ; AG) were administered to patients with BRPC on days 1 and 8, along with tislelizumab (200 mg) on day 1 intravenously (IV) every three weeks. Surgical intervention was assessed after two cycles of treatment. Primary endpoint was adverse events (AE) and R0 resection rate. Secondary endpoints were objective response rate (ORR) and progression free survival (PFS) by mRECIST, relapse-free survival (RFS) and overall survival (OS). Results: Between October 2022 and December 2023, 21 patients were enrolled in the study. At the end of the last follow-up (January 27, 2024), 15 patients had a best response of partial response, the ORR was 71.4% according to mRECIST. The disease control rate (DCR) was 85.7%. The 12-months PFS rate, and 12-months OS rate were 68.2% (95% CI: 38.0%–86.0%), and 63.8% (95% CI: 33.2%–88.3%), respectively. After the two cycles of neoadjuvant therapy, 14 patients underwent resection (66.7%,14/21) and the R0 resection rate was 100%. For those patients who did not undergo surgery, 3 of them achieved PR but refused surgery, 3 patients developed disease progression and lost the chance of surgery. 1 patient died of severe pneumonia caused by H1N1 infection. So far the safety of neoadjuvant treatment was satisfied, no grade 4 or above treatment-related-adverse events (TRAEs) were observed. Grade 3 TRAEs were reported in 3(14.29%) patients. Frequently occurring adverse events were grade 1-2, including myelosuppression (90.47%), albuminuria (80.95%), nausea (61.90%), elevated aspartate aminotransferase (47.62%) and elevated alanine aminotransferase (38.10%). Grade 3 or higher adverse events were pneumonia (4.76%), elevated AST (4.76%), elevated ALT (4.76%) and myelosuppression (4.76%). Conclusions: Anti-PD-1 inhibitor tislelizumab plus AG chemotherapy displayed promising antitumor activity and acceptable safety profile for patients with BRPC. Clinical trial information: ChiCTR2200063680.