Immunomodulatory Treatment of Interstitial Lung Disease Associated With Surfactant Related Gene Variants

Scientific justification : Variants in surfactant-related genes (SRG) explain approximately 6% of familial pulmonary fibrosis (FPF). The pathophysiology is unknown and seems to involve endoplasmic reticulum stress in type 2 alveolar epithelial cells. Variable improvement in the prognosis of childhood and adult interstitial lung disease (ILD) associated with a variant of a SRG, initially reported to be lethal within months of diagnosis, has been observed since the consensual use of prednisone, azithromycin and hydroxychloroquine targeting endoplasmic reticulum stress, without demonstration of the efficacy of any of these treatments alone or in combination. The investigators hypothesize that a treatment combining prednisone, azithromycin and hydroxychloroquine is safe and could improve the prognosis of adult patients with ILD associated with SRG variant. Main objective and primary endpoint : Main objective: Evaluate the efficacy of triple immunomodulatory therapy (prednisone, azithromycin and hydroxychloroquine) for 12 months in patients with ILD associated with a variant of a surfactant-related gene. Primary endpoint: Difference in forced vital capacity decline between the 2 groups at one year. Secondary objectives and endpoints : Secondary objectives: 1. tolerance of the triple therapy, 2. correlation between the respiratory, radiological and clinical functional response, 3. quality of life of the patients, 4. overall survival, transplant-free survival, exacerbation free-survival, hospitalization-free survival Secondary endpoints: 1. Clinical and biological tolerance (occurrence of an adverse effect during treatment), ECG (at 3, 6, 9, 12 months after randomization) (only HCQ or AZI patients) and ophthalmological (at one year after randomization) 2. Thoracic CT scan and PFT at 6 months and one year after randomization 3. Quality of life questionnaire (EORTC QLQ-C30, v3.0) at 3 months, 6 months, 9 months and one year after randomization, 4. Collection of vi