AB0224 SUSTAINABLE LOW DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS: REAL-WORLD EXPERIENCE WITH TOCILIZUMAB

Abstract

Background:Sustainability, the ability of drugs to maintain remission or low disease activity (LDA) in patients with rheumatoid arthritis (RA), plays a crucial role for the prevention of structural damage to joints and thus, preserving patients’ functional capacity, health-related quality of life and general sense of well-being. Therefore, studying the sustainable effectiveness of tocilizumab (TCZ) as a monotherapy or combined with methotrexate (MTX) is important (1).Objectives:We aimed to examine to what extend TCZ, alone or combined with MTX, could achieve and further sustain LDA in patients with long-standing RA in the light of current, strictly index-based definitions of LDA and to compare the two versions of DAS28 in patients in real clinical practiceMethods:85 RA patients treated with TCZ for at least eighteen months were consecutively enrolled in the present single-center, retrospective cohort study. All participants met the 1987 ACR classification criteria and attended the rheumatology department of University Hospital “St. Marina” Varna in an outpatient setting. Patients receiving pre-filled syringe contained 162 mg TCZ once weekly subcutaneously. Real-world data were extracted and analyzed from patient’s full medical file. For each visit, disease activity score 28 with ESR and CRP (DAS28-ESR and DAS28-CRP) and simple disease activity index (SDAI) were calculated simultaneously according to generally adopted formulas. A twelve-month result was determined for sustained LDA at each of the patient’s three visits (at 6-month intervals), according to DAS28 and SDAI. Descriptive statistics, Chi square test, Cochran´s Q test, kappa statistic were used, a binary logistics model was compiled to study the impact. Significance level of p <0.05.Results:Two hundred fifty-five patient visits were analyzed. The mean durations of RA and treatment with TCZ were 12.6 (±9.6) years and 3.64 (±1.8) years, respectively. The mean age of patients was 60.3 years (37-87 years), 80% were women, 24.7% were obese, 65.9% have concomitant hypertension. 61.2% of patients are treated with combination therapy TCZ with MTX.Of all patients, these with a sustained 12-month LDA were 41.2%, 28.2% or 23.5% depending on the studied index (DAS28-CRP, SDAI, or DAS28-ESR, respectively).A 12-month SDAI LDA was found in a significantly small proportion of patients (28.2%, p = 0.001). The DAS28 ESR determined a proportion similar to SDAI (23.5%, p> 0.05), while according to the DAS28 CRP, patients with a sustained 12-month LDA were significantly more (41.2% p = 0.005). A moderate level of agreement was found between the assessments of SDAI and the two variants of DAC28 when determining 12-month results of Tocilizumab treatment (DAS28-ESR k = 0.511, p <0.001 and DAC28-CRP k = 0.618, p <0.001). No relationship was found between the combination of TCZ with MTX and the patients’ chance of a sustained 12-month LDA, regardless of which index the result was measured.Patients with hypertension were significantly less likely to have sustained 12-month LDA according to SDAI and DAS 28 ESR (OR 0.135, 95% CI 0.048-0.386; OR 0.313, 95% CI 0.111-0.882, respectively), but not according to DAS28 CRP.Conclusion:Sustained 12- month LDA with TCZ in patients with long-term RA remains uncommon in daily clinical practice. Co-administration of MTX is not associated with an increased likelihood of achieving a sustained LDA in the analysis of long-term responses. Patients with concomitant hypertension are less likely to be in a sustained 12-month LDA, according to SDAI and DAS28-ESR. The results according to DAS28 ESR, but not according to DAS28CRP are comparable to those of SDAI when measuring long-term results of treatment with TCZ.