We observed a negative trend in the association, although not statistically significant, between the HLA-DRB1 *09:01 allele, which is the second significant risk allele in Korean RA population, and treatment response to abatacept (OR = 0.19 [0.01–1.11], P = 0.068) or TNFi (OR = 1.09 [0.61–1.92], P = 0.78)5. Here, HLA-DRB1 is linked to rheumatoid arthritis.