Intestine-lung Axis of Cystic Fibrosis Patients Treated With the Combination Elexacaftor/Tezacaftor/Ivacaftor

Cystic fibrosis is a systemic disease, which affects in particular the respiratory and digestive systems of patients, sites of chronic inflammation. A new combination of elexacaftor/tezacaftor/ivacaftor has proven its efficacy for the treatment of patients aged 12 years and over with two F508del mutations or a so-called "minimal function" mutation associated with one F508del mutation. European marketing authorization was obtained in August 2020 and access in France should therefore arrive soon. Given that this treatment targets new mutations and that the efficacy seems greater than with LUM/IVA, it is important to assess its impact on the microbiota and the pulmonary and digestive inflammation of patients. It is therefore a question of taking advantage of the experience of the Lum-Iva-Biota cohort, and the validated and operational sample circuit established in the various participating centers to set up a biological collection for the collection and storage of sputum and stools of patients during the first year of treatment with elexacaftor/tezacaftor/ivacaftor, in order to study the effect of treatment on the lung and digestive microbiota/mycobiota and inflammation.

Inclusion Criteria: * To have cystic fibrosis (sweat test \> 60 mmol/l); * Carrier of at least one DeltaF508 mutation; * Be followed in the current care by a participant in the CRCM study; * Start treatment with elexacaftor/tezacaftor/ivacaftor in routine care, according to the indications in the Marketing Authorization at the time of inclusion; * Be of the age specified in the marketing authorization in force; * Person affiliated or beneficiary of a social security scheme; * Consent obtained by the patient (for adult patients) or the holders of parental authority (for minor patients) before any examination required by the research and oral and/or written consent by the participant (depending on his or her age) . * Patient agreeing to take part in cohort follow-up studies of patients treated with elexacaftor/tezacaftor/ivacaftor, included in the French cystic fibrosis register (cf. Study by Pr BURGEL and/or MODUL CF). Exclusion Criteria: * Start of treatment with elexacaftor/tezacaftor/ivacaftor as part of a therapeutic trial. * Patient already on CFTR modulator (including lumacaftor/ivacaftor) * Vulnerable people (pregnant woman, person under guardianship/curators)