The three peptides (GVF27, HVA36, and IMY47) have been extensively characterized for their activities, alone or in combination with antibiotics, on a broad spectrum of CF clinical isolates. The researchers have also evaluated their anti-biofilm properties, their affinity for endotoxins, their immunomodulatory properties and their toxicity in vivo on mice, thanks to the support of the FFC CFaCore facility. All three cryptic peptides show significant antimicrobial activities on CFclinical isolates, good affinity for endotoxins, and significant antibiofilm properties. Nevertheless IMY 47 is the only nontoxic when administered in vivo (by aerosol treatments and also by subcutaneous injections) and moreover, it presents in its sequence a cryptic potent anti-biofilm peptide (IMY25) that researchers have successfully produced and in vitro characterized. Starting from these observations, future efforts will be dedicated to exploring these peptide therapeutic potentialities in cell-based and preclinical models of CF. They may be novel anti-biofilm drugs of human origin and alone or combined with antibiotics, could crucially improve the treatment to eradicate bacterial lung invasion.