Abstract Objectives Rheumatoid arthritis (RA) is a chronic inflammatory disease of immune-mediated origin. Janus kinase inhibitors (JAK inhibitors) have expanded therapeutic options in recent years; however, clinical response varies among patients, and no biomarkers are currently available to predict their efficacy. The aim of this study was to analyze the association between pharmacogenetic variants and clinical response to JAK inhibitors in patients with RA. Methods An observational, ambispective, single-center study was conducted in adult patients diagnosed with RA and treated with JAK inhibitors. Sociodemographic and clinical characteristics were collected from electronic medical records. Five genetic variants previously associated with response to biological therapies in RA were analyzed through genotyping. Results A total of 56 patients were included in the study. A statistically significant association was observed between the rs20575 variant of the TNFRSF10A gene and clinical remission, with CG or CC genotypes being more frequent among patients who achieved remission at the last available follow-up. Additionally, the rs1801274 polymorphism of the FCGR2A gene was associated with a lower likelihood of achieving low disease activity or remission in patients with the AA genotype, both at 12 months and at the last available follow-up. Conclusions This study highlights the potential of pharmacogenetics to personalize RA treatment by establishing, for the first time, that specific genetic variants involved in immune response may significantly influence the efficacy of JAK inhibitors. These findings open new perspectives for optimizing therapeutic decisions, although further studies are needed to validate them.
Plasencia-Rodríguez et al. (2026) studied this question.