139P - Ablation combined with tislelizumab in treating hepatocellular carcinoma: A phase II trial

Background

Combining local thermal ablation with immune checkpoint inhibitors for small hepatocellular carcinoma is uncharted territory. This phase II trial aimed to evaluate the safety and efficacy of combining thermal ablation with tislelizumab, an anti-PD-1 antibody, in patients with Barcelona Clinic Liver Cancer stage A or B HCC.

Methods

This phase II trial (NCT04652440) included newly diagnosed and recurrent HCC patients with 1 or 2 lesions measuring 2-5 cm. Patients received their first tislelizumab dose intravenously within one day before percutaneous thermal ablation, followed by infusions every three weeks for a total of four doses. Primary endpoints were safety and tolerability. Secondary endpoints included complete response rate by first thermal ablation, local recurrence rate, distant metastasis rate, and 1- and 2-year disease-free survival and overall survival rates. This study was presented as a poster at ESMO Asia 2023 in Singapore, and this is an update on the present study.

Results

The study completed recruiting 30 HCC patients in August 2023. The CR1 was 93.33%, with 26 patients (86.67%) completing the entire treatment. One patient discontinued due to a severe adverse event related to thermal ablation and did not receive further medication, while another switched to resection after a second failed ablation. By the data cut-off on May 27, 2024, 23 patients (76.7%) experienced grade ≥3 treatment-related adverse events. The most common were elevated alanine aminotransferase (N=16) and aspartate aminotransferase (N=23) levels on the first-day post-ablation, with most recovering after supportive treatment. Additionally, 12 patients experienced grade 1-2 immune-related adverse events (irAEs), including rash (N=9), pruritus (N=6), and anorexia (N=4), with no grade ≥3 irAEs reported. One patient developed renal failure six months after the last dose of tislelizumab and was diagnosed with multiple myeloma, likely unrelated to the study treatment. The one-year DFS rate was 71.4% (95% confidence interval, 56.4% to 90.4%).

Conclusions

Combining thermal ablation with tislelizumab showed acceptable safety and tolerability, with no unexpected SAEs. Long-term outcomes will be disclosed in the future.

Clinical trial identification

NCT04652440.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.