D23-06 Characteristics and Disease Progression Among Patients With Progressive Fibrotic Hypersensitivity Pneumonitis: Findings From the ILD-PRO Registry

Abstract Rationale Patients with fibrotic hypersensitivity pneumonitis (fHP) who have developed progressive pulmonary fibrosis (PPF) may be treated with combinations of immunosuppressants (IS) and antifibrotic (AF) drugs. Treatment patterns and outcomes in patients with fHP have not been well described in prospective multicenter studies. We characterized patients with fHP in the ILD-PRO Registry, which enrolled patients with fibrotic ILDs other than idiopathic pulmonary fibrosis, who had met criteria for ILD progression within the prior 24 months. Methods Patients were categorized by the use of IS other than corticosteroids, AF drugs, both, or neither at registry enrollment. Demographic and clinical characteristics were described in groups defined by these treatment patterns. The risk of disease progression during follow-up in the registry, defined as ≥ 10% relative decline in FVC % predicted, lung transplantation, or death from any cause, was described with Kaplan-Meier estimates. Results At registry enrollment, of 186 patients with progressive fHP, 60 (32%) were treated with IS only, 34 (18%) with AF drugs only, 42 (23%) with both IS and AF drugs, and 50 (27%) with neither (figure). The most commonly used IS agents were mycophenolate (36% of all patients) and azathioprine (11% of all patients). Other IS agents were used by 2% of the cohort. Nintedanib was used by 72 (39%) and pirfenidone by four (2%) patients. Mean age was 69 years and similar across treatment groups. Mean FVC % predicted was 61 and similar across treatment groups. Mean DLCO % predicted was 34 among patients treated with both IS and AF, compared to 41-43 in the other treatment groups. Patients treated with both IS and AF drugs had a higher rate of supplemental oxygen use at rest than the other groups (45% vs 22-27%). Overall, the risk of disease progression in the 18 months following registry enrollment was 50% (figure). Conclusions In patients with progressive fHP, IS and AF drugs were commonly used, both alone and in combination. Patients receiving combination therapy with IS and AF drugs had lower DLCO and greater oxygen use. Despite frequent use of both IS and AF treatments, half of patients with fHP who met criteria for progressive ILD experienced further disease progression within 18 months. These findings highlight the need for further study to determine the effects of specific treatment strategies on progression in patients with progressive fHP. This abstract is funded by: The IPF-PRO/ILD-PRO Registry is supported by Boehringer Ingelheim Pharmaceuticals, Inc and run in collaboration with the Duke Clinical Research Institute and enrolling centers.