Targeted Therapy for Restoring CFTR Activity: From Experimental to Clinical Features.

Cystic fibrosis (CF) is one of the most common rare genetic diseases. It is caused by pathogenic variants of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. More than 2200 variants have been identified in the CFTR gene that need detailed knowledge and functional characterization in order to develop specific therapeutic strategies. The traditional therapy for CF relied on addressing symptoms through mucolytic and antibiotic treatments, respiratory physiotherapy and aerosol therapy. However, in the last few years, the development of small new molecules targeting and restoring the underlying CFTR channel defect marked an important step in CF treatment. In addition, the implementation of patient-specific cellular models allowed the evaluation of pharmacological responses, leading to therapeutic advances in the direction of personalized treatment. The focus of this review is to describe and discuss the strategies for restoring the CFTR functional defects depending on the specific CFTR pathogenic variants. In particular, the review highlights the possible application of experimental and clinical drugs to CF treatment, which may allow improvements in patients' quality of life and life expectancy. The in vitro testing of therapeutic drugs (theratyping) is performed nowadays through the use of several cellular models, especially those derived from patient-specific tissues. This topic is a hot point in CF research and the review also aims to provide an overview of the state of the art in theratyping. The novelty of this review is the integrated view of the most recent achievements in precision diagnostics and therapy of CF at the molecular, cellular and clinical level, which are able to change the natural history of this disease.