The impact of tocilizumab on hepatic enzyme levels in rheumatoid arthritis patients: a narrative review

Rheumatoid arthritis (RA) is an autoimmune disease affecting 0.5-1% of the global population. Tocilizumab (TCZ), a monoclonal antibody, offers a promising treatment option for RA patients unresponsive to disease-modifying antirheumatic drugs (DMARDs). While multiple studies have demonstrated the efficacy and safety of TCZ, some have reported associations between TCZ treatment and elevations in hepatic transaminase levels. This review explores the relationship between TCZ therapy and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in RA patients previously treated with DMARDs. For this narrative review, a comprehensive search was conducted in two major databases, PubMed and Google Scholar, for articles published in English between 2013 and 2023. The search utilized key terms such as "tocilizumab", "hepatic transaminases", "ALT", "AST", "rheumatoid arthritis patients", and "DMARDs". From 402 initially identified articles, 10 studies published between 2013 and 2023 were selected for review, including observational studies, narrative reviews, and systematic reviews. These studies examined the impact of TCZ on liver enzyme levels in RA patients receiving DMARDs, with varying sample sizes. TCZ demonstrates clinical efficacy in patients with RA unresponsive to previous treatments. Although mild and transient elevations in liver enzymes, particularly ALT, have been observed, serious hepatic adverse events remain uncommon. Although current evidence indicates that TCZ shows promise as a treatment for RA, the variability among studies and the quality of the included evidence call for a careful interpretation of the findings. Continued liver function monitoring and individualized dosing are recommended to support its safe use.