Discontinuation of immune checkpoint inhibitors in hepatocellular carcinoma: a retrospective cohort study

The optimal timing to discontinue immune checkpoint inhibitor (ICI) therapy in hepatocellular carcinoma (HCC) patients with clinical benefits remains unclear. This study aimed to assess the outcomes of HCC patients after ICI discontinuation. Patients with HCC were retrospectively screened and those discontinued ICI therapy in the absence of progressive disease (PD) were included. Responses at discontinuation were evaluated per response evaluation criteria in solid tumors (RECIST) version 1.1 and modified RECIST (mRECIST). Patients were classified into five subgroups according to the cause of discontinuation: complete response (CR), partial response (PR), stable disease (SD) per RESICT version 1.1, adverse event (AE), or others. Progression-free survival (PFS) and overall survival (OS) since ICI start or after ICI discontinuation were assessed. A total of 66 patients were included. The median follow-up was 29.33 months. The median PFS since ICI start was 30.83 months [95% confidence interval (CI): 24.93-36.72], and the median OS was not reached. The median PFS after discontinuation was 20.6 months (95% CI: 7.63-33.56), and the median OS after discontinuation was not reached. Univariate analysis showed that age, treatment after discontinuation, Response (RECIST version 1.1) at discontinuation and modified response (mResponse per mRECIST) at discontinuation were significantly associated with PFS after discontinuation, while age and mResponse at discontinuation were significantly associated with OS after discontinuation. Multivariate analysis further demonstrated that mResponse at discontinuation and treatment after discontinuation were independently associated with PFS after discontinuation, while age was independently associated with OS after discontinuation. ICIs might be discontinued in HCC patients with a response of CR per mRECIST. Patients with a response of PR/SD per mRECIST or elder age could continue ICI therapy after achieving clinical benefits. Tyrosine kinase inhibitor (TKI) maintenance therapy might help to prevent progression after ICI discontinuation.