Safety and Preliminary Efficacy of Pembrolizumab Following Transarterial Chemoembolization for Hepatocellular Carcinoma: The PETAL Phase Ib Study.

PURPOSE: Transarterial chemoembolization (TACE) may prime adaptive immunity and enhance immunotherapy efficacy. PETAL evaluated safety, preliminary activity of TACE plus pembrolizumab and explored mechanisms of efficacy. PATIENTS AND METHODS: Patients with liver-confined hepatocellular carcinoma (HCC) were planned to receive up to two rounds of TACE followed by pembrolizumab 200 mg every 21 days commencing 30 days post-TACE until disease progression or unacceptable toxicity for up to 1 year. Primary endpoint was safety, with assessment window of 21 days from pembrolizumab initiation. Secondary endpoints included progression-free survival (PFS) and evaluation of tumor and host determinants of response. RESULTS: Fifteen patients were included in the safety and efficacy population: 73% had nonviral cirrhosis; median age was 72 years. Child-Pugh class was A in 14 patients. Median tumor size was 4 cm. Ten patients (67%) received pembrolizumab after one TACE; 5 patients after two (33%). Pembrolizumab yielded no synergistic toxicity nor dose-limiting toxicities post-TACE. Treatment-related adverse events occurred in 93% of patients, most commonly skin rash (40%), fatigue, and diarrhea (27%). After a median follow-up of 38.5 months, objective response rate 12 weeks post-TACE was 53%. PFS rate at 12 weeks was 93% and median PFS was 8.95 months [95% confidence interval (CI): 7.30-NE (not estimable)]. Median duration of response was 7.3 months (95% CI: 6.3-8.3). Median overall survival was 33.5 months (95% CI: 11.6-NE). Dynamic changes in peripheral T-cell subsets, circulating tumor DNA, serum metabolites, and in stool bacterial profiles highlight potential mechanisms of action of multimodal therapy. CONCLUSIONS: TACE plus pembrolizumab was tolerable with no evidence of synergistic toxicity, encouraging further clinical development of immunotherapy alongside TACE.

Efficacy and safety of frontline systemic therapy for advanced HCC: A network meta-analysis of landmark phase III trials.

Background & Aims: Direct comparisons across first-line regimens for advanced hepatocellular carcinoma are not available. We performed a network metanalysis of phase III of trials to compare first-line systemic treatments for hepatocellular carcinoma in terms of overall survival (OS), progression-free survival (PFS), objective response rate, disease control rate, and incidence of adverse events (AEs). Methods: After performing a literature review from January 2008 to September 2022, we screened 6,329 studies and reviewed 3,009 studies, leading to identification of 15 phase III trials for analysis. We extracted odds ratios for objective response rate and disease control rate, relative risks for AEs, and hazard ratios (HRs) with 95% CIs for OS and PFS, and used a frequentist network metanalysis, with fixed-effect multivariable meta-regression models to estimate the indirect pooled HRs, odds ratios, relative risks, and corresponding 95% CIs, considering sorafenib as reference. Results: Of 10,820 included patients, 10,444 received active treatment and 376 placebo. Sintilimab + IBI350, camrelizumab + rivoceranib, and atezolizumab + bevacizumab provided the greatest reduction in the risk of death compared with sorafenib, with HRs of 0.57 (95% CI 0.43-0.75), 0.62 (95% CI 0.49-0.79), and 0.66 (95% CI 0.52-0.84), respectively. Considering PFS, camrelizumab + rivoceranib and pembrolizumab + lenvatinib were associated with the greatest reduction in the risk of PFS events compared with sorafenib, with HRs of 0.52 (95% CI 0.41-0.65) and 0.52 (95% CI 0.35-0.77), respectively. Immune checkpoint inhibitor (ICI) monotherapies carried the lowest risk for all-grade and grade ≥3 AEs. Conclusions: The combinations of ICI + anti-vascular endothelial growth factor, and double ICIs lead to the greatest OS benefit compared with sorafenib, whereas ICI + kinase inhibitor regimens are associated with greater PFS benefit at the cost of higher toxicity rates. Impact and Implications: In the last few years, many different therapies have been studied for patients with primary liver cancer that cannot be treated with surgery. In these cases, anticancer drugs (alone or in combination) are given with the intent to keep the cancer at bay and, ultimately, to prolong survival. Among all the therapies that have been investigated, the combination of immunotherapy (drugs that boost the immune system against the cancer) and anti-angiogenic agents (drugs that act on tumoural vessels) has appeared the best to improve survival. Similarly, the combination of two types of immunotherapies that activate the immune system at different levels has also shown positive results. Systematic Review Registration: PROSPERO CRD42022366330.