ABSTRACT
OBJECTIVE: Our aim was to assess efficacy and safety of Rituximab (RTX) in patients with refractory Idiopathic inflammatory myopathies (IIM) from a monocentric cohort. Thereafter, we evaluated the efficacy of a low-dose RTX regimen as a remission-maintenance therapy. METHODS: We retrospectively evaluated a cohort of patients affected with IIM treated with RTX. All patients were refractory to glucocorticoids (GC) and at least one immunosuppressant. Two infusions of 1 g two weeks apart were considered as standard cycle of RTX, a single dose of 1 g every six months was deemed as a low-dose RTX regimen. Complete and partial response were defined according to physician's judgment, laboratory and radiological features. RESULTS: Thirty-six patients affected with IIM were enrolled. Eighteen patients (50%) required the use of RTX for muscular involvement, 6 (16.7%) for interstitial lung disease (ILD), 12 (33.3%) for both myositis and ILD. We observed complete response to RTX in 25 patients (69.4%), partial response in 7 (19.4%) and no response in 4 (11.1%), with an overall response of 88.8% (partial and complete response). From the subgroup of twenty-five patients that achieved a complete response, six were treated with a low dose maintenance therapy maintaining a complete response to RTX. Twenty-six patients who achieved a complete or partial response were able to decrease the mean daily GC dose. Infections were the major adverse events detected in our study. CONCLUSIONS: RTX shows favorable outcomes in refractory patients with IIM. A low-dose regimen of RTX appears to be effective in maintaining remission after induction with standard dose. Key Points ⢠The precise pathogenic mechanism of idiopathic inflammatory myopathies (IIM) remains elusive; however, a growing body of data support the autoimmune hypothesis. In this context, rituximab, a B cell-depleting agent, has emerged as a second-line therapeutic option in IIM. ⢠Several studies have assessed It its effectiveness in refractory IIM patients. ⢠Limited information exists on the use of Rituximab as maintenance therapy in patients who have achieved remission following induction therapy with Rituximab.
ABSTRACT
BACKGROUND: The usefulness of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) for the assessment of idiopathic inflammatory myopathies (IIMs) is acknowledged, but laboratory standardization remains a challenge. We detected MSAs/MAAs by multi-analytic line immunoassay (LIA) and particle-based multi-analyte technology (PMAT) in a multicenter cohort of patients with IIMs. METHODS: We tested the sera from 411 patients affected with definite IIM, including 142 polymyositis (PM), 147 dermatomyositis (DM), 19 cancer-associated myositis, and 103 overlap myositis syndrome (OM), and from 269 controls. MSAs/MAAs were determined by 16Ags LIA in all sera, and anti-HMGCR by ELISA in 157/411 IIM sera and 91/269 control sera. The analytical specificity of LIA/HMGCR ELISA was compared with that of PMAT in 89 MSA+ IIM sera. RESULTS: MSAs/MAAs were positive in 307/411 (75%) IIM patients and 65/269 (24%) controls by LIA (Odds Ratio 9.26, 95% CI 6.43-13.13, p < 0.0001). The sensitivity/specificity of individual MSAs/MAAs were: 20%/100% (Jo-1), 3%/99.3% (PL-7), 4%/98.8% (PL-12), 1%/100% (EJ), 0.7%/100% (OJ), 9%/98% (SRP), 5.6%/99.6% (TIF1γ), 4.6%/99.6% (MDA5), 8%/96% (Mi-2), 1.5%/98% (NXP2), 1.7%/100% (SAE1), 4%/92% (Ku), 8.5%/99% (PM/Scl-100), 8%/96% (PM/Scl-75), and 25.5%/79% (Ro52). Anti-HMGCR was found in 8/157 (5%) IIM patients and 0/176 (0%) controls by ELISA (p = 0.007). Concordance between LIA/HMGCR ELISA and PMAT was found in 78/89 (88%) samples. Individual MSAs detected by LIA were associated with IIM subsets: Jo-1 with PM and OM, PL-12 with OM, Mi-2, TIF1γ, and MDA5 with DM, SRP with PM, and PM/Scl-75/100 with OM (p < 0.001 for all). CONCLUSIONS: Since MSAs are mostly mutually exclusive, multi-specific antibody profiling seems effective for a targeted clinical-serologic approach to the diagnosis of IIMs.
ABSTRACT
OBJECTIVES: Patients with connective tissue diseases can develop interstitial lung disease (ILD), leading to a progressive fibrosing ILD (PF-ILD) phenotype in some cases. We aimed to investigate the occurrence of PF-ILD in idiopathic inflammatory myopathies (IIMs), and factors potentially predicting this phenotype. Secondary aims were to assess the radiological pattern and factors associated with IIMs-ILD. METHODS: Patients with IIMs from our multicentric prospective cohort were retrospectively evaluated. Data were recorded at IIMs and ILD diagnosis, and during follow-up. Patients with ILD were classified according to the predominant high-resolution CT (HRCT) pattern: non-specific interstitial pneumonia (NSIP), usual interstitial pneumonia (UIP) and organising pneumonia (OP). PF-ILD was defined according to the 2022 American Thoracic Society (ATS), European Respiratory Society (ERS), Japanese Respiratory Society (JRS) and Latin American Thoracic Society (ALAT) guidelines. Univariate and multivariate analyses were performed to identify factors associated to ILD and to PF-ILD. RESULTS: Of 253 patients with IIMs, 125 (49%) had ILD: 99 (78%) at IIMs diagnosis and 26 (22%) during follow-up (21/26 within 5 years). Multivariate analysis identified anti-Jo-1, anti-MDA5, anti-Ro52, high score on manual muscle test, mechanic's hands and Raynaud's phenomenon as independently associated with ILD. The predominant HRCT pattern was NSIP (50% of patients), followed by UIP (28%) and OP (22%). At 1-year follow-up, PF-ILD occurred in 18% of IIMs-ILD. PF-ILD was predicted by anti-MDA5, heliotropic rash, xerostomia and xerophthalmia at univariate but not at multivariate analysis. CONCLUSION: Patients with IIM should be carefully screened for ILD at IIMs diagnosis and yearly during follow-up. All patients with IIMs-ILD should be carefully monitored to capture ILD progression since a consistent proportion of them are expected to develop PF-ILD.