Comparative Evaluation of Respiratory Assessments in Inclusion Body Myositis from INSPIRE-IBM Study

Topic:

Other

Poster Number: 109 S

Author(s):

Isela Hernandez, MS, University of California, Irvine, Marie Wencel, PMP, University of California, Irvine (CCR), Namita Goyal, MD, University of California, Irvine, Spencer Matthews, University of California, Irvine, Olimpia Carbunar, MD, University of Miami, Miriam Freimer, MD, Ohio State University, Mazen Dimachkie, MD, KUMC, Colin Quinn, MD, University of Pennsylvania, Thomas E. Lloyd, MD, PhD, Johns Hopkins University, Payam Mohassel, MD, Department of Neurology, Johns Hopkins University School of Medicine, Conrad Weihl, MD, PhD, Washington University St Louis, Aziz Shaibani, MD, Nerve and Muscle Center of Texas, Leo Wang, MD, PhD, University of Washington, Nizar Chahin, MD, Oregon Health & Science University, Anthony A. Amato, MD, Brigham and Women's Hospital, Matthew Wicklund, MD, University of Colorado, Stacy Dixon, MD, University of Colorado, Perry Shieh, MD, University of California Los Angeles, Laura Herbelin, University of Missouri, Richard Barohn, MD, University of Missouri, Rabi Tawil, MD, University of Rochester, Emma Ciafaloni, MD, FAAN, University of Rochester Medical Center, Rochester, NY, USA, Tahseen Mozaffar, MD, University of California, Irvine, Study Group INSPIRE-IBM, MDA, All Institutions for INSPIRE-IBM

Background:
Anti-NT5c1A antibodies have been proposed as a potential biomarker for inclusion body myositis (IBM) and associated with increased disease severity, including respiratory functions. A 2016 study involving a cohort of 25 patients reported that NT5c1A seropositive individuals had significantly lower forced vital capacity (FVC) values (p = 0.005), suggesting more severe respiratory involvement. Subsequent literature has been mixed, some supporting the 2016 findings, while others not finding support for this notion.
Validation of these findings in a larger cohort of IBM patients in a controlled research setting is needed to clarify these associations. We compared the severity of respiratory dysfunction in NT5c1A seropositive and seronegative IBM patients across multiple timepoints: Baseline, 6-months, 12-months, and 18-months.

Methods: Data was collected from the INSPIRE-IBM Study: A 13-center observational prospective ongoing study involving 150 patients with IBM. Results from the Baseline, 6-month, 12-month, and 18-month visit were analyzed: FVC % predicted (sitting and supine), Maximum inspiratory pressure (MIP), and Maximum expiratory pressure (MEP). We compared the rate of change in pulmonary function (FVC, MIP, and MEP) between seropositive and seronegative IBM patients using a Generalized Estimating Equation (GEE) model with an AR-1 working correlation structure. The model included time, serum status, and their interaction. The primary focus was on the interaction term, which indicates whether the rate of change differs between groups. A significance level of 0.05 was utilized to determine statistical significance.

Results: Among all pulmonary assessments, only FVC (Sitting) Percent Predicted approached statistical significance (p=0.053); all other measures (FVC Supine, MIP, MEP) were not statistically significant. However, a consistent trend was observed: the seropositive group showed lower average rates of change across all time points (Baseline, 6, 12, and 18 months) for each respiratory measure. Additional data has been collected, and further analysis is currently in progress. The results will be presented at the upcoming conference

Conclusion: Based on earlier findings, we anticipate that NT5c1A-seropositive participants will again demonstrate lower pulmonary function test results, providing greater evidence of respiratory involvement in this subgroup.