Investigation of the Mechanism of Lorlatinib-Induced Hepatotoxicity: Reactive Metabolites of Lorlatinib Activate Inflammasomes.

Lorlatinib, a third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor, is widely used to treat ALK-positive nonsmall cell lung cancer. However, lorlatinib has occasionally been associated with severe liver injury. Immune-mediated adverse events are frequently provoked by certain pharmacological agents or their reactive metabolites. However, the specific contribution of immune pathways to hepatotoxicity caused by lorlatinib is yet to be fully elucidated. In the present study, the potential for direct inflammasome stimulation by lorlatinib was examined in differentiated THP-1 cells. This was accompanied by an evaluation of inflammasome-activating factors present in the culture supernatants of FLC-4 cells treated with lorlatinib. Our results showed that lorlatinib did not directly activate inflammasomes in differentiated THP-1 cells; however, the supernatants from FLC-4 cells activated inflammasomes in differentiated THP-1 cells following treatment with lorlatinib. Detection of pyrido-pyrazole-containing metabolites in FLC-4 cells suggests that these reactive metabolites activate inflammasomes. Exposure of FLC-4 cells to lorlatinib resulted in elevated extracellular concentrations of heat shock protein 90 (HSP90), a damage-associated molecular pattern (DAMP). These findings suggest that the reactive metabolites of lorlatinib promote hepatocellular release of damage-associated molecular patterns, which in turn activate inflammasomes. Thus, inflammasome activation may be an important step in the activation of the immune system by lorlatinib and may cause immune-related adverse events in some patients.