AB0583 COMPARISON OF THE RITUXIMAB (RTM) IN MONOTHERAPY REGIMEN AND CYCLOPHOSPHOMIDE (CYP) EFFICACY AND SAFETY IN SYSTEMIC SCLEROSIS (SSC) WITH INTERSTITIAL LUNG DISEASE (ILD)

Background: CyP is considered as a drug of choice for the treatment of ILD in the patients with SSc. However, the use of CyP leads to rather limited and transient improvement of the pulmonary fibrosis. RTM is considered as a promising therapeutic agent for treatment of ILD in the patients with SSc. However, the limited number of RTM-treated patients, considerably different dose regimens, cumulative doses, and observation periods does not allow univocal conclusions on RTM efficacy or definitive recommendations on RTM use in the patients with SSc. Objectives: To compare the impact of CyP and RTM a single-agent therapy on SSc clinical manifestation and activity, and the safety of these agents in the open-label prospective non-randomized study. Methods: 71 patients with the confirmed SSc diagnosis and ILD evidence based on multispiral computed tomography findings were enrolled into the study. All patients received low-dose and moderate-dose glucocorticoids regimens. Group A (n=35) received RTM as a single therapy agent over the follow-up period 13.3±2.3 months in a total dose 1.35±0,5g (the patient’s average age was 45.0±15 years, with female proportion 80%; SSc duration 6.3±2.3 years; diffused/localized forms 1.3/1). Group B (n=36) received parenteral CyP for 12±6 months at total dose 10.6±5 g (the average age 47±12 years, females 92%, SSc duration 5.0±4.8 years, diffused/localized forms 1.6/1). The age, gender proportion, SSc form and SSc duration, FVC, were similar in the both groups. The time courses of FVC, modified skin count (mRss, points), activity index (EScSG, points) were assessed in the study. Results: The glucocorticoids starting dose that patients received at the time of inclusion in the study was significantly higher in group B compared to group A (p=0.03). Only after a year of CyP therapy, the dose of glucocorticoids was reduced to the starting dose in group A. In Groups A and B the therapy was associated with significant decrease in mRss (р=0.02 and 0.009, respectively) and EScSG (р=0.00017 and 0.000165, respectively). Evaluation of FVC time course in Groups A and B revealed significant FVC increase (р= 0.002 and 0.034, respectively), with median increment about 5%. The 10% FVC increase and decrease was similar in both groups. The therapy was better tolerated in RTM-treated group: during RTM therapy adverse reactions emerged in significantly lower proportion of the patients (4/11%) compared with CyP-treated group (19/53%), р=0,0000. Conclusion: Both agents effectively alleviated skin induration and EScSG, and significantly improved FVC. However, the glucocorticoids doses that needed to be used during anti-B cell therapy were significantly lower compared to CyP treated patients. The RTM single therapy was better tolerated compared to CyP. The study findings substantiate potential use a RTM single therapy both as a first-line agent for ILD treatment in the patients with SSc, and in the event of CyP inefficacy of poor tolerability. Disclosure of Interests: None declared