Clin Exp Pediatr. 2023 Jun 28.
Most rare diseases(orphan diseases) still lack approved treatments despite major advances in research providing the tools to understand their molecular basis, as well as legislation providing regulatory and economic incentives to expedite the development of specific therapies. Addressing this translational gap is a multifaceted challenge, for which a key aspect is the selection of the optimal therapeutic modality for translating advances in rare disease knowledge into potential medicines, known as orphan drugs. There are several strategies for the development of orphan drugs for rare genetic disorders including protein replacement therapies, small molecule therapies(e.g. substrate reduction therapy, chemical chaperone therapy, cofactor therapy, expression modification therapy, read through therapy), monoclonal antibodies, antisense oligonucleotide, small interfering RNA or exon skipping therapies, gene replacement and direct genome editing therapies, mRNA therapy, and cell therapy as well as drug repurposing. Each strategy has its strength and limitations for orphan drug development. Furthermore, numerous hurdles are present in clinical trials in rare genetic disease because of difficulty in patient recruitment, unknown molecular physiology and natural history of the disease, ethical concerns about pediatric patients, and regulatory challenges. To address these barriers, the rare genetic diseases community including academic institutions, industry, patient advocacy groups, foundations, payers and government regulatory and research organizations, must be engaged as a partnership in discussions about the issues.
Keywords: Clinical trial; Drug development; Orphan drug; Rare disease; Strategy