Background: Optimal nutritional status represents one of the therapeutics goal in patients with cystic fibrosis (pwCF). High-caloric diet with adequate pancreatic enzyme replacement therapy represents daily aims. Studies have shown that the CFTR modulators therapy have a benefic effect on pulmonary function, increasing the spirometry values. But does this new therapy have any effect on improving the nutritional status? Recently papers underlined the benefic effect on patients? weight, but an optimal nutritional status in pwCF is defined by a BMI percentile above 50.

Objective: to find out if CFTR modulators therapy has any effect on improving nutritional status in pwCF.
Method: an interventional study was started in May 2022 when the triple therapy was initiated; 12 paediatric patients were enrolled. Each patient had its weight and height measured before the treatment and at 1, 3 and 6 months of treatment. BMI and corresponding percentile were calculated.

Results: We found statistically significant differences between mean BMI percentile before and after 3 (34.4 vs 43.8, p= 0.013), respectively 6 months of treatment (34.4 vs 43.4, p= 0.0011). No statistically significant difference was found at 1 month of treatment (p= 0.06). 33.3% of patients had an optimal nutritional status before the new therapy was initiated. Only one patient succeeds to achieve an optimal nutritional status and his BMI percentile increased above percentile 50 at 3 months. He managed to keep this status at 6 months of therapy, when 41.6% of patients had an optimal nutritional status.

Conclusions: Patients? weight increased under CFTR modulator therapy but an optimal nutritional status is hard to be achieved.