Long-term efficacy of sarilumab on the progression of interstitial lung disease in rheumatoid arthritis: the KEIO-RA cohort and literature review.

Objectives: To clarify the impact of sarilumab (SAR) on the progression of interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA).

Methods: We conducted a retrospective review of all consecutive RA patients from the KEIO-RA cohort who visited our institution between 2018 and 2024 and received SAR treatment. Patients were followed for 24 months from the initiation of SAR. The primary outcome was the rate of progression of ILD as assessed by high-resolution computed tomography (HRCT). We also conducted a literature review regarding the efficacy of SAR on RA-ILD in PubMed, Web of Science, and Scopus databases.

Results: Among 123 cases, 21 (17.1%) had ILD. The median age at SAR initiation was 56 years, and 71.4% were female. Except for 6 cases, SAR was administered as monotherapy via subcutaneous injection at 200 mg every two weeks. During SAR treatment, 18 cases (85.7%) exhibited stable HRCT findings, coupled with improvements in arthritis. Two cases with NSIP and OP patterns demonstrated improvements in both HRCT findings and arthritis post-SAR treatment. One case experienced an exacerbation of ILD at 18 months, with worsening arthritis observed prior to the deterioration of ILD. Serum KL-6 levels also improved or remained stable after SAR initiation, except in one case of ILD exacerbation. There were no adverse events, including serious infections, during the observation period. Additionally, our literature review identified a case of RA-ILD treated with SAR and achieved remission of arthritis and ILD.

Conclusions: In our study, SAR exhibited encouraging efficacy in stabilising RA-ILD in most cases.