Mixing the Old with the New: Drug Repurposing for Immune Deficiency in the Era of Precision Medicine and Pediatric Genomics

The document discusses the potential of drug repurposing in the context of precision medicine and pediatric genomics, particularly for treating rare immune deficiencies. It highlights the challenge of developing new therapies for rare diseases, which are individually infrequent but collectively common, and notes that out of over 7,000 rare diseases, only about 600 treatment options are available. The paper cites the example of Activated phosphoinositide 3-kinase-d (PI3Kδ) syndrome (APDS), a rare immune deficiency caused by gain-of-function mutations, and the use of next-generation sequencing technologies to diagnose such conditions. The editorial emphasizes the advantages of drug repurposing, which involves using existing drugs with known safety profiles for new indications. It references a case reported by Valencic et al. in the same issue, where theophylline, a drug commonly used for pulmonary obstruction, was successfully repurposed to treat an 11-year-old girl with APDS, leading to symptom amelioration and reduced infection frequency. This case exemplifies how drug repurposing can be a valuable strategy in treating rare diseases and underscores the importance of considering off-label uses of approved medications.