Clinical features and management for CDK4/6 inhibitor-DILI

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i)-ribociclib, abemaciclib, palbociclib-are the standard of care for metastatic breast cancer. Although hepatotoxicity is a frequent adverse event, data on CDK4/6i drug-induced liver injury (DILI) remain scarce. We aimed to define the incidence, clinical presentation, severity, management, and relapse of CDK4/6i-related DILI in a large real-world cohort.

Retrospective multicentre study including all patients who developed ≥grade 2 DILI (alanine aminotransferase/aspartate aminotransferase >3 × upper limit of normal) while receiving CDK4/6i between January/2018 and December/2022. Severity was assessed according to Common Terminology Criteria for Adverse Events version 5 (CTCAEv5) and DILI-International Expert Working Group criteria.

Among 2,222 CDK4/6i-treated patients, 100 (4.5%, 95% CI 3.7-5.4%) developed DILI. Incidence was significantly higher for ribociclib (8.3%, 95% CI 6.3-10.7%) and abemaciclib (6.7%, 95% CI 4.6-9.3%) than for palbociclib (1.4%, 95% CI 0.8-2.2%) (Difference, p <0.001). Most cases were grade 2 or 3 (CTCAE) and mild (DILI-International Expert Working Group), although moderate DILI (bilirubin >2 × ULN, n = 12) occurred with all three CDK4/6i. The most frequent pattern was hepatocellular, whereas cholestatic was mainly observed with abemaciclib. Liver biopsy findings (n = 11) were heterogeneous and, together with biochemical results, did not support an immune-mediated mechanism as the primary driver. Corticosteroids (n = 20) did not impact time to grade 1 or alanine aminotransferase normalisation. DILI recurred in 28.2% of CDK4/6i rechallenges (n = 85). Among patients treated with ribociclib, rechallenge with an alternative CDK4/6i was associated with lower risk of recurrence (p = 0.010).

DILI caused by ribociclib and abemaciclib are more common that with palbociclib. The absence of immune-mediated features and the limited benefit of corticosteroids question their routine use. After CDK4/6i reintroduction, DILI recurrence rate was 28%. Standardised management is needed, particularly following the approval of ribociclib and abemaciclib as adjuvant therapy.

Although hepatotoxicity is a frequent adverse event, real-world data on CDK4/6i DILI remain scarce. DILI associated with ribociclib and abemaciclib is more common than for palbociclib, although moderate DILI (bilirubin >2 × normality) was observed with the three drugs. The absence of immune-mediated features and the limited benefit of corticosteroids question their routine use in CDK4/6i DILI. Relapse of DILI after rechallenge with a CDK4/6i was 28%, with all cases presenting as mild. The increasing use of CDK4/6i (metastatic breast cancer and ribociclib and abemaciclib as adjuvant therapy) highlights the need of standardising the management of CDK4/6i DILI.