956P - Phase II study of adjuvant tislelizumab combined with interferon-α and active surveillance in hepatocellular carcinoma patients with microvascular invasion

Background

Microvascular invasion (MVI) is closely associated with high risk of recurrence and poor long-term survival in HCC patients. For these patients, active and effective adjuvant therapy is of great significance to improve the prognosis. Therefore, we explored the efficacy and safety of interferon-α (IFN-α) combined with PD-1 monoclonal antibody (tislelizumab, TIS) as adjuvant therapy for HCC patients with MVI.

Methods

In this phase 2 study, histologically confirmed HCC patients who had undergone curative resection with MVI, Child-Pugh A, and an ECOG PS ≤1 were enrolled. Patients separately received TIS (200 mg IV Q3W) plus IFN-α (30 μg BIW) or active surveillance until disease progression, intolerable toxicity or withdrawal of consent. The primary endpoint was recurrence free survival (RFS). Secondary endpoints included overall survival (OS) and safety.

Results

From January 2021 to December 2021, TIS plus IFN-α group and active surveillance group enrolled 24 and 14 patients, respectively. Baseline characteristics were generally comparable between two groups, including MVI grade (M1: 90.0% vs 85.7%; M2: 10.0% vs 14.3%) and any tumours diameter > 5cm (65.0% vs 50.0%) in TIS plus IFN-α, respectively. At data cutoff (17 Apr 2023), RFS was not reached in TIS plus IFN-α group (95%CI: 9.8-NE), whereas in active surveillance group was 17.09 month (95%CI: 4.8-NE). 1-year RFS rate in TIS plus IFN-α and active surveillance group was 79.2% (95%CI: 0.5-0.9) and 50.0% (95%CI: 0.2-0.7), separately. Median OS was not reached in either group. No severe postoperative complications were observed. In TIS plus IFN-α group, Grade 1 or higher AEs were mainly rash (20.0%), pyrexia (15.0%), pruritus (10.0%) and diarrhea (10.0%).

Conclusions

These results suggested that HCC patients with MVI may benefit from adjuvant tislelizumab plus IFN-α, which can be tested in a future confirmatory trial. We will continue follow-up and update the data further. In the meantime, related basic experiments are underway.

Clinical trial identification

ChiCTR2000037461.

Editorial acknowledgement

Legal entity responsible for the study

Fudan University Shanghai Cancer Center.

Funding

Shanghai Shenkang Hospital Development Center (No. SHDC2020CR3031B).

Disclosure

All authors have declared no conflicts of interest.