Rituximab as a rescue treatment added on mycophenolate mofetil background therapy in progressive systemic sclerosis associated interstitial lung disease unresponsive to conventional immunosuppression

Objective: To test whether the use of rituximab (RTX) is effective and safe as a rescue therapy add-on treatment to mycophenolate (MMF) in patients with progressive systemic sclerosis-associated interstitial lung disease (SSc-ILD) in whom conventional immunosuppressants (IS) have failed.

Methods: Longitudinal retrospective observational study of a cohort of patients with SSc-ILD that started treatment with RTX due to ongoing lung function impairment despite treatment with glucocorticoids and IS (cyclophosphamide and/or MMF). All patients were treated with 2 or more cycles of RTX and evaluated for at least 12 months.

Results: Twenty-four patients were included. Before initiation of RTX the mean decline in%pFVC and %pDLCO during the previous 2 years (delta) was -12.9% and -12.5%, respectively. After 1 year of treatment with RTX, a significant improvement in %pFVC (∆+8.8% compared to baseline, 95% CI: -13.7 to -3.9; p = 0.001) and%pDLCO (∆+4.6%, 95% CI: -8.2 to -0.8; p = 0.018) was observed. In addition, there was a significant reduction in the median dose of prednisone and it could be suspended in 25% of patients. At 2 years of treatment, RTX had been discontinued in 9 patients (due to adverse events in 3 cases and inefficacy in 6). In the 15 patients (62.5%) that completed 24 months of therapy, the statistically significant amelioration in pulmonary function test parameters was maintained: ∆%pFVC: +11.1% (95% CI: -17.6 to -4.5; p = 0.003) and ∆%pDLCO: +8.7% (95% CI: -13.9 to -8.3; p = 0.003).

Conclusion: Based on our results, RTX's use as an add-on treatment to MMF appears to be effective as a rescue therapy in patients with a more aggressive SSc-ILD phenotype.