PETAL protocol: a phase Ib study of pembrolizumab after transarterial chemoembolization in hepatocellular carcinoma

Transarterial chemoembolization (TACE) is the treatment of choice for intermediate-stage hepatocellular carcinoma (HCC). Recent data suggest that TACE may boost the efficacy of anti-PD-1 immunotherapy. The authors present the trial protocol for PETAL, a phase Ib study, which will assess the safety and bioactivity of pembrolizumab, an anti-PD-1 antibody, following TACE in HCC. After a run-in phase evaluating six patients to establish preliminary safety, up to 26 additional participants will be enrolled. Pembrolizumab will be administered three-times weekly for 1 year or until progression, starting 30–45 days after TACE. The primary objective is to determine safety and the secondary objective is to preliminarily evaluate efficacy. Radiological responses will be evaluated every four cycles. Clinical Trial Registration: NCT03397654 ( ClinicalTrials.gov )