Effect of rituximab on the manifestations of activity and pulmonary function in patients with systemic sclerosis: one-year follow-up evaluation

Abstract

The choice of drugs for the treatment of interstitial lung disease (ILD) associated with systemic sclerosis (SS) is currently very limited. Data from a number of studies show that rituximab (RTM) can improve lung function and reduce the severity of skin fibrosis in patients with SS.Objective: to evaluate the efficiency of RTM in a cohort of patients with SS-associated ILD after one-year follow-up. The indications for prescribing RTM were: 1) the inefficiency of standard therapy with glucocorticoids and immunosuppressants (ISs) or the impossibility of their use; 2) the early stage (first 3 years of the disease) with signs of poor prognosis, such as diffuse form, high skin scores (>14), male gender, rapid progression with a significant initial decline in forced vital capacity (FVC) and/or diffusion lung capacity (DLC), and a high anti-Scl-70 antibody positivity.Subjects and methods. The investigators selected a group of patients who had at least two assessment points at a 12-to-18 month interval (the mean follow-up period of 13±2 months) and took at least 1 g of RTM during this period. The investigation included 71 patients with a valid diagnosis of SS. Multi-slice spiral computed tomography (MSCT) revealed ILD in 90% of patients. The disease duration was 5.6±4.4 years. The presence of anti-Scl-70 antibodies was detected in 73% of patients. The mean cumulative dose of RTM was 1.43±0.6 g; 48 patients in Group 1 received ≤2 g of RTM (the mean dose, 1.1±0.1 g) and 23 patients in Group 2 took ≥2 g of RTM (mean dose, 2±0.6 g). Before starting treatment with RTM, all the patients received concomitant therapy with prednisone and 45% - with immunosuppressants.Results and discussion. The results assessed by a physician showed that good and moderate effects of the therapy were observed in 52 (73.2%) and 16 (22.6%) patients, respectively; no effect was seen in 3 (4.2%) patients. Overall, 95.8% of patients reported various degrees of improvement. There were significant changes as reductions in the disease activity index, skin scores, C-reactive protein and IgG levels, the number of patients with a high antinuclear antibody level, and the mean dose of prednisolone as well as increases in an oral aperture size, left ventricular ejection fraction, and 6-minute walk test scores. There were no changes in pulmonary artery systolic pressure and the HAQ DI. FVC increased from 77.35±19.9 to 82.6±20.7% (p=0.001). A minimal clinically significant increase in FVC ≥5% was noted in 41 (57.7%) people. The overall improvement in FVC (ΔFVC) reached 5.24%, while the changes were more significant in Group 2 (ΔFVC 8.98%) than in Group 1 (ΔFVC 3.75%; p=0.01). DLC remained stable, but there were significant group differences: ΔDLC was 3.75% in Group 2 and, conversely, decreased in Group 1 (1.6%; p=0005). The safety profile of the therapy was regarded as good and quite comparable with both the safety profile of ISs and the use of RTM in other trials. Infectious complications were recorded to be most common in 11 (15%) people. Of these, upper respiratory tract infections developed in 7 patients; plantar phlegmon occurred in one case; urinary tract infection and herpes zoster were detected in two and one cases, respectively.The results of this study confirm data from other studies that have demonstrated that RTM exerts a positive effect on SS-associated ILD. We were the first to show the association of positive changes in the measures of pulmonary function tests with the dose of RTM.

Keywords

• systemic sclerosis
• interstitial lung disease
• anti-b cell therapy
• rituximab