Tocilizumab and rituximab for systemic sclerosis interstitial lung disease: a real-world cohort analysis

SSc-interstitial lung disease (ILD) is one of the leading causes of mortality in SSc. Data from randomized controlled trials (RCTs) support rituximab and tocilizumab monotherapy but there are limited data regarding their use for those who fail standard immunomodulatory therapies.

SSc patients treated with rituximab or tocilizumab were retrospectively identified in a single centre cohort. Linear mixed effect models were used to analyse before and after treatment lung function trajectory, and identify patient characteristics associated with treatment response.

A total of 127 patients were included for analysis. Fifty-one of 94 (54.2%) and 13 of 33 (39.4%) of the rituximab and tocilizumab cohorts, respectively, were receiving concurrent MMF. Pre-treatment decline in absolute change % forced vital capacity (%FVC)/year and % diffusion capacity for carbon monoxide (%DLCO)/year, respectively, was similar in both cohorts (-3.2% and -4.0% rituximab, and -3.2% and -3.6% tocilizumab). Both treatments resulted in lung function stabilization (%FVC/year and %DLCO/year: 1.2% and +0.2% rituximab cohort, 1.0% and 1.0% tocilizumab cohort). Anti-topoisomerase antibody (ATA)-positive patients had a significant response on %FVC/year to tocilizumab compared with ATA-negative patients. Gender had a significant impact on %FVC/year response to rituximab, with males responding to a greater degree than females. Age, ILD extent and skin subset had no impact on treatment response.

Combination rituximab or tocilizumab with background immunosuppressive therapy is associated with stabilization in lung function trajectory among those who remain refractory to standard immunosuppressives. Specific patient characteristics have an impact on lung function response. Improved FVC response among ATA patients receiving tocilizumab validate data from RCTs.