QR-443

QR-443 is an experimental antisense oligonucleotide (AON) developed by ProQR Therapeutics for the treatment of cystic fibrosis (CF). It was specifically designed to target the mRNA of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, with a focus on correcting the R117H mutation. By binding to the mutant mRNA, QR-443 aimed to restore the production of functional CFTR protein, thereby improving chloride transport in the lungs. Intended for administration via inhalation, the drug was part of ProQR's early-stage RNA therapy pipeline but was eventually discontinued as the company shifted its strategic focus toward other clinical candidates and its Axiomer RNA editing platform.