Evaluation of SIRT Followed by Immunotherapy for Treatment of Hepatocellular Carcinoma With Portal Vein Thrombosis

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, being the third leading cause of cancer-related death worldwide, with approximately 745 000 deaths reported annually.

For advanced patients, including patients with tumoral portal vein thrombosis (PVT), most treatment guidelines recommend systemic therapy, either combination immunotherapy (IO) or combination of immunotherapy and anti-angiogenic treatment for first line option.

Results for PVT patients are provided in one trial with a median overall survival of 14.2 months with IO underlying the necessity to improve treatment of PVT patients. Two recent other phase 3 trials also reported positive results for different IO regimen.

Selective internal radiation therapy (SIRT) using yttrium-90 (90Y)-loaded glass microspheres (TheraSphereTM) can be used for patients with early stage to locally advanced HCC including PVT patients without extrahepatic spread (EHS). TheraSphereTM is recognized and is reimbursed in France for PVT patients without EHS, since 2019.Several retrospective studies have shown promising results for PVT patients.

Nowadays use of SIRT in locally advanced HCC is regaining interest based on the results of the randomized DOSISPHERE-01 study including non-operable patients, about 70% with PVT. This randomized Phase II trial using 90Y-loaded microspheres sought was noted the effectiveness of 90Y-loaded microspheres using a personalized dosimetry approach versus a standard dosimetry approach.

The use of a systemic treatment as IO after a locoregional treatment with the strong local debulking effect of SIRT is logical and of interest. Indeed, the most frequent pattern of progression after SIRT is recurrence in an untreated area, including untreated liver or EHS. Patients are then usually referred to IO.

Such kind of therapeutic approach, using SIRT followed by IO has already been evaluated in a phase 2 study using nivolumab after 90Y loaded resin microspheres with promising efficacy without safety deterioration.

The aim of this study is to evaluate SIRT followed by IO used according to their current indications in advanced HCC patient with PVT patients and without EHS.