RP-ILD is a devastating condition frequently associated with MDA5-DM. Antifibrotics are used to control disease progression of ILD, but their benefit and clinical significance are still not well known in patients with RP-ILD. Here we report our experience of using antifibrotics for patients with RP-ILD associated with MDA5-DM.

This is a case series of RP-ILD associated with MDA5-DM diagnosed between 2010 and 2022 in our institute. Clinical characteristics and outcomes were retrospectively reviewed.

Fifteen patients presented with RP-ILD, all of whom were treated with steroid pulse and immunosuppressive agents. Eight patients (median age 71.5 yo, 5 males) did not receive antifibrotics in the acute phase (non-antifibrotics group). Seven patients (median age 53 yo, 6 males) commenced antifibrotics (antifibrotics group; 6 pirfenidone, 1 nintedanib) within 2 weeks after starting intensive treatment. The median values in the antifibrotics group were as follows: ferritin, 556 ng/mL; KL-6, 1358 U/mL; LDH, 409 U/L. Median Ichikado CT score (Lian X, et al. Chest 2020; scores >133 are related with higher mortality) was 200, and MCK score (Gono T, et al. Arthritis Rheumatol 2021; score of 2 relates to >50% mortality) was 2 in five patients. Despite the severe disease state in the antifibrotics group, 3-month survival was 71.4% in the antifibrotics group versus 25% in the other patients.

Although the number of cases is limited, our findings suggest a possible effect of antifibrotics for RP-ILD associated with MDA5-DM. Further studies are needed to clarify the significance of antifibrotics in this condition.