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A1639 - Mycophenolate and Rituximab in Patients with Interstitial Lung Disease Associated with Connective Tissue Disorder in the Setting of Positive Myositis Antibodies: A Retrospective Analysis
Author Block: R. Burnside1, I. C. Mira-Avendano2; 1Pulmonary and Critical Care Medicine, Mayo Clinic Florida, Jacksonville, FL, United States, 2MAYO CLINIC - FLORIDA, Jacksonville, FL, United States.
RATIONALE Evidence based on prior Retrospective Analyses recommends mycophenolate (MMF) and rituximab for treatment of Interstitial Lung Disease (ILD) associated with Connective Tissue Disorders (CTD), but it is not clear if the same efficacy exists for the specific set of patients with positive myositis antibodies, as some of them have just recently been recognized. We did a retrospective analysis of a cohort of patients with ILD related CTD who demonstrated specific and non-specific myositis antibodies treated with MMF and Rituximab. METHODS Among patients diagnosed with Interstitial Lung Disease associated with Connective Tissue Disorder in our Pulmonary-Rheumatology Clinic from 2012 onward, we identified those with positive Myositis-Specific Antibodies (MSA) and Myositis-Associated Antibodies (MAA) and evaluated the effect of treatment with mycophenolate and rituximab. Twenty-nine patients were treated with mycophenolate and nineteen with rituximab. Of those included in final analysis, 10 received both mycophenolate and rituximab at some point in their follow-up. Treatment outcomes were defined as forced vital capacity (FVC) and diffusion capacity of the lung for carbon monoxide (DLCO) at 6 and 12 months. RESULTS Forty-eight patients were found to have either MSA or MAA. These included 17 patients with positive anti-Jo-1 antibodies, 11 with anti-SSA-52 (7 with combined SSA-52 and one of the Antisynthetase (AS) Antibodies), 6 with anti-PL-7, 4 with PL-12, 5 each with positive MDA-5 and PM-SCL and 6, 4, 3, and 2, with positive anti-U2/1SN-RNP,-MI-2, Ku, and -TIF1-Gamma, respectively. 27% had concomitant isolation of MSA and MAA, with no cases of combined AS Antibodies in the same patient. In the mycophenolate subset, there was a statistically significant increase in FVC from initial visit to 6 months of 0.26 L (9.6%) and increase of DLCO of 1.07 ml/l/min (8.9%). Improvement at 12 months was sustained with an average increase of 0.16 L (4%) in FVC and 0.34 ml/l/min (1.14%) in DLCO. Regarding patients treated with rituximab, there was an increase of 0.09 L (2.54%) and 0.1 ml/l/min (0.9%) at 6 months, and 0.16 L (4.4%) and 0.34 ml/l/min (1.14%) at 12 months in FVC and DLCO, respectively. Steroid dose was decreased on average to 5 mg in all patients at 12 months. Myositis was present in only 50% of the patients. The main radiologic pattern was NSIP. CONCLUSION Mycophenolate and Rituximab seem to be a good option for treatment of ILD associated with positive Myositis Antibodies. The phenotype of patients varies based on the respective antibody.