Employment of the Envisia Genomic Classifier in Conjunction With Cryobiopsy in Patients With Undiagnosed Interstitial Lung Disease

Abstract

BackgroundThe Envisia Genomic Classifier (EGC) is a clinically validated molecular diagnostic test identifying usual interstitial pneumonia (UIP), increasing the diagnostic confidence for idiopathic pulmonary fibrosis (IPF) in patients with interstitial lung disease (ILD). Research QuestionWhat is the association of EGC and lung cryobiopsy on clinical management decisions in patients with fibrotic ILD? Study Design and MethodsRetrospective analysis of patients at multi-medical centers. We assessed the change in management strategy following EGC and cryobiopsy. We evaluated the association between genomic UIP classification and disease progression using ATS definition of progressive pulmonary fibrosis (method 1); or combined endpoint of death from any cause, lung transplant, or ⩾10% relative decline in forced vital capacity (FVC) (method 2). RESULTSIn patients that were EGC positive for UIP (gcUIP+), 78.6% were diagnosed with IPF. Cryobiopsy and EGC test results changed management strategy for 59.5% of patients in the cohort that was gcUIP+, 21.4% of patients that had indeterminate cryobiopsy interpretations were gcUIP+, leading to change in treatment strategy of an additional 16.7%. There was a decrease in follow up without treatment from 64.3 % to 11.9 % (P<0.001). Utilization of immunosuppressive drugs decreased from 23.8% to 9.5% (P=0.06) and there was an increase in treatment with antifibrotics drugs from 11.9% to 71.4% (P<0.001). A Kaplan-Meier curve of disease progression did not reach statistical significance on multivariable analysis (HR 1.4, 95% CI 0.4–4.2; p=0.55; method 1) and (HR 1.3, 95% CI 0.8-2.1; p=0.29; method 2). Analysis of gcUIP+, patients who were not prescribed antifibrotics showed disease progression compared to patients with gcUIP- (HR=1.8, 95%CI=0.99-3.4, p=0.053) ConclusionsThis study suggests that combined EGC and cryobiopsy is associated with change in therapeutic strategy in patients with undiagnosed ILD. The EGC might serve as a predictor for disease progression in patients not treated with antifibrotics.