Effect of cystic fibrosis modulator therapies on serum levels of fat-soluble vitamins.

This is a prospective, multicenter study of a cohort of 224 cystic fibrosis (CF) patients treated with CF transmembrane conductance regulator (CFTR) modulators (CFTRm). Our aim was to prospectively analyze the effect of CFTRm treatment on fat-soluble vitamin serum levels. Demographic and clinical data were recorded, and fat-soluble vitamin levels were analyzed at baseline, and at 6 and 12 months after starting treatment. Two groups were analyzed separately: patients receiving dual therapy lumacaftor/ivacaftor or tezacaftor/ivacaftor (Lum/Tez+Iva), and those on triple therapy with elexacaftor/tezacaftor/ivacaftor (ETI). We found that treatment with ETI produced a significant increase in vitamin D and A levels within the first 6 months, which was maintained at 12 months. However, with dual therapy, we observed an increase only in vitamin A levels within the first 6 months, which was not maintained at 12 months. No differences were found in vitamin E serum levels between the groups.