Faecal Microbiota Transplantation to Ameliorate Nintedanib-induced Diarrhea in Patients With Idiopathic Pulmonary Fibrosis

Inclusion Criteria: Phase 1 (faecal samples collection) * Patients aged ≥18 years when signing the informed consent; * Diagnosis of IPF within 4 weeks based on 2018 ATS/ERS/JRS/ALAT Guidelines (2) as confirmed by the investigator based on chest HRCT scan and if available surgical lung biopsy; * Patients already on antifibrotic therapy with nintedanib according to clinical practice. Phase 2 (FMT procedure) \- Patients who develop diarrhea of grade 2 or 3 according to the Common Terminology Criteria (CTC) for Adverse Events (AE) version 5.0 (12) within 8 weeks of baseline visit. Exclusion Criteria: * Women of childbearing potential or pregnant; * History of colorectal surgery or cutaneous stoma; * Food allergies; * Recent (\<6 weeks) therapy with drugs that could possibly alter gut microbiota (e.g. antibiotics, probiotics, proton pump inhibitors, immunosuppressants and/or metformin); * Any documented active or suspected malignancy, except appropriately treated basal cell carcinoma of the skin, "under surveillance" prostate cancer or in situ carcinoma of uterine cervix; * Decompensated heart failure or heart disease with ejection fraction lower than 30%, severe respiratory failure, psychiatric disorders, pregnancy or inability to provide informed consent. * Fecal sample unable for FMT according to the opinion of the Investigators (e.g. positive for pathogens); * (phase 2 only) Diarrhea from known causes (e.g. infectious gastroenteritis, Clostridium difficile infection, coeliac disease, inflammatory bowel disease, irritable bowel syndrome, chronic pancreatitis and/or biliary salt diarrhea).