Interleukin-6-receptor polymorphisms rs12083537, rs2228145, and rs4329505 as predictors of response to tocilizumab in rheumatoid arthritis.

Tocilizumab (TCZ), a monoclonal antibody targeting the human interleukin-6-receptor (IL-6R), is indicated for the treatment of rheumatoid arthritis (RA). We examined whether three IL6R single-nucleotide polymorphisms rs12083537, rs2228145 (formerly rs8192284), and rs4329505 with previously reported functional effects were associated with clinical response to TCZ in a retrospective study cohort consisting of 79 RA patients. Three months after initiation of TCZ therapy, changes in swollen joint count (SJC) and, subordinately, tender joint count (TJC), serum-CRP, DAS28-CRP, and EULAR-response were tested for association with the IL6R-haplotype or genotype.