Characterization of liver injury induced by cancer immunotherapy using immune checkpoint inhibitors

Background & aims: Immunotherapy for metastatic cancer can be complicated by the onset of hepatic immune-related adverse events (IRAEs). This study compared hepatic IRAEs associated with anti-programmed cell death protein 1 (PD-1)/PD ligand 1 (PD-L1) and anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) monoclonal antibodies (mAbs).

Methods: Among 536 patients treated with anti-PD-1/PD-L1 or CTLA-4 immunotherapies, 19 (3.5%) were referred to the liver unit for grade ≥3 hepatitis. Of these patients, nine had received anti-PD-1/PD-L1 and seven had received anti-CTLA-4 mAbs, in monotherapy or in combination with anti-PD-1. Liver investigations were undertaken in these 16 patients, including viral assays, autoimmune tests and liver biopsy, histological review, and immunostaining of liver specimens.

Results: In the 16 patients included in this study, median age was 63 (range 33-84) years, and nine (56%) were female. Time between therapy initiation and hepatitis was five (range, 1-49) weeks and median number of immunotherapy injections was two (range, 1-36). No patients developed hepatic failure. Histology related to anti-CTLA-4 mAbs demonstrated granulomatous hepatitis including fibrin ring granulomas and central vein endotheliitis. Histology related to anti-PD-1/PD-L1 mAbs was characterised by lobular hepatitis. The management of hepatic IRAEs was tailored according to the severity of both the biology and histology of liver injury: six patients improved spontaneously; seven received oral corticosteroids at 0.5-1 mg/kg/day; two were maintained on 0.2 mg/kg/day corticosteroids; and one patient required pulses and 2.5 mg/kg/day of corticosteroids, and the addition of a second immunosuppressive drug. In three patients, immunotherapy was reintroduced without recurrence of liver dysfunction.

Conclusions: Acute hepatitis resulting from immunotherapy for metastatic cancer is rare (3.5%) and, in most cases, not severe. Histological assessment can distinguish between anti-PD-1/PD-L1 and anti-CTLA-4 mAb toxicity. The severity of liver injury is helpful for tailoring patient management, which does not require systematic corticosteroid administration.

Lay summary: Immunotherapy for metastatic cancer can be complicated by immune-related adverse events in the liver. In patients receiving immunotherapy for metastatic cancer who develop immune-mediated hepatitis, liver biopsy is helpful for the diagnosis and evaluation of the severity of liver injury. This study demonstrates the need for patient-oriented management, which could eventually avoid unnecessary systemic corticosteroid treatment.