143P - Ablation combined with tislelizumab in treating hepatocellular carcinoma: A phase II trial

Background

The combination of local thermal ablation with immune checkpoint inhibitors perioperatively for small hepatocellular carcinoma (HCC) is yet to be explored. The aim of this phase II trial was to evaluate the safety and tolerability of thermal ablation in combination with tislelizumab, an anti-PD-1 antibody, in patients with HCC of Barcelona Clinic Liver Cancer (BCLC) stage A or B, and to make a preliminary evaluation of the efficacy of this treatment modality.

Methods

This phase II trial (NCT04652440) enrolled newly diagnosed and recurrent HCC patients with 1 or 2 lesions of 2-5 cm in size. This study included two stages. The first stage included 6 patients for dose-limited toxicity (DLT) observation. Only if DLT appeared in < 2 patients, the other 24 patients would be included. Enrolled patients received the first dose of tislelizumab intravenously within 1 day before percutaneous thermal ablation, followed by infusions every 3 weeks for totally 4 doses. The primary endpoints were safety and tolerability. Secondary endpoints included the rate of complete response by first ablation (CR1), local recurrence rate, distant metastasis rate, and 1- and 2-year disease-free survival (DFS) and overall survival (OS) rates.

Results

No DLT occurred in the first 6 patients, and the study completed recruiting a total 30 subjects in July 2023. Twenty-six subjects had already finished their study treatment and were followed regularly. One patient withdrew her informed consent after completion of the ablation and the first dose of study medication. The other 3 were still on tislelizumab therapy. Until the time of data cut-off (July 30, 2023), the most common adverse events were increased alanine aminotransferase (N=15) and aspartate aminotransferase (N=19) on the first day after ablation. The majority recovered after supportive treatment. 10 patients experienced grade 1-2 immune-related adverse events (irAEs), the most common were rash (N=8), pruritus (N=5), and anorexia (N=4). No ≥3 grade irAEs occurred.

Conclusions

Thermal ablation combined with tislelizumab showed acceptable safety and tolerability with no unexpected SAEs observed. Results of efficacy will be disclosed in future.

Clinical trial identification

NCT04652440.

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.