A prospective, single-arm, phase II clinical study of tislelizumab in combination with lenvatinib for perioperative treatment of resectable primary hepatocellular carcinoma with high risk of recurrence.

e16218 Background: Surgery is the main radical treatment for hepatocellular carcinoma (HCC), but the high postoperative recurrence rate makes the survival benefit of patients limited. Neoadjuvant therapy mainly reduces postoperative recurrence by controlling micrometastasis and reducing preoperative tumor load and other high recurrence risk factors, but there are limited data on its application in liver cancer. Tislelizumab, a PD-1 monoclonal antibody, has shown promising efficacy with acceptable safety profile in combination with lenvatinib in the first-line treatment of advanced HCC. This study aims to explore the safety and feasibility of tislelizumab combined with lenvatinib in the neoadjuvant therapy and adjuvant therapy of resectable HCC. Methods: This prospective, single-center, single-arm phase II study (NCT04834986) enrolled patients with histologically confirmed resectable HCC who were at high risk of recurrence, as assessed by the investigators before surgery. Patients did not have any medical treatment in the past, with ECOG of 0-1, and had adequate organ and bone marrow function. Eligible patients received 4 cycles with tislelizumab (200mg, d1, Q3W) combined with Lenvatinib (8mg/kg, PO, qd) and surgery was performed within 4 weeks after treatment. At 4-8 weeks after surgery, adjuvant therapy was started with tislelizumab (200mg, d1, Q3W) and lenvatinib (8mg/kg, PO, qd) for at least half a year or until disease progression or intolerance of adverse reactions. Primary endpoints were safety and feasibility; secondary endpoints were ORR, 1 and 2-years DFS%, pCR, and DFS. Results: From Sep 7,2021 to Nov 9,2022, 24 patients (median age, 57.5 years) were enrolled, with most patients were males (95.8%) and 22 patients (91.7%) had HBV infection. All patients had Child-Pugh grade A and ECOG PS 0. The median treatment period was 4 cycles. In 24 patients, 17 patients (70.8%) underwent R0 resection, 3 patients (3/17, 17.6%) achieved complete pathological response (PCR), and 6 patients (6/17, 35.3%) achieved major pathological response rate (MPR, necrosis > 70%). 3 patients (12.5%) had significant tumor shrinkage and refused surgery. 1 patient (4.2%) is waiting surgery. 3 patients (12.5%) developed disease progression. According to RECIST1.1, ORR was 54.2% (13/24, CR 1, PR 12), DCR was 87.5%. According to mRECIST, ORR was 75.0% (18/24, CR 6, PR 12), DCR was 87.5%. No grade 3 or above adverse events were observed during neoadjuvant treatment period. The most common adverse events of any grade were rash (14/24,58.3%), hypertension (5/24,20.8%) and diarrhea (4/24,16.7%). Conclusions: Tislelizumab in combination with lenvatinib was well tolerated and showed promising efficacy as a neoadjuvant therapy for resectable HCC with high risk of recurrence. Clinical trial information: NCT04834986 .