Genetic Therapies for Rare Diseases
Rare diseases have low market demand for therapeutic drugs due to their low prevalence, resulting in high R&D costs for their therapeutic drugs and slow progress of related therapeutic strategies. In recent years, with the development of molecular biology technology and the concept of precision medicine, gene therapy technology has made significant progress in the research of genetic rare diseases, and its research results play an important role in clinical diagnosis, drug development, and treatment of rare diseases, providing the possibility of a complete cure for the diseases.
Overview of Gene Therapy
Gene therapy is a treatment that corrects or displaces a mutated disease-causing gene. The introduction of the target gene into the target cell works in three ways: enabling the expression of the transferred gene, suppressing or modulating the expression of the target gene, or modifying the target gene. Currently, gene therapy has been a successful drug after many gene therapies received official approval. The rise of emerging gene editing technologies has increased and broadened the use of gene therapy in disease treatment.
Gene therapy in a broad sense includes all methods of correcting and repairing DNA defects. In clinical practice, gene therapy is usually performed using viral vectors, most commonly adeno-associated virus (AAV) vectors. These vectors can infect human cells like viruses and carry normal human genes into the nucleus, effectively causing the "infected" cells to produce functional proteins that can eventually alleviate or even cure the disease.
Fig. 1 Gene therapy and gene editing approaches. (Braga L A M, et al., 2022)Application of Gene Therapy in Rare Disease Treatment Research
Gene therapy plays an important role in rare disease management. With the advantages of single-dose therapy for rare diseases, gene therapy offers effective lifelong improvement compared to conventional treatment options. The development of gene therapies for rare diseases includes a wide range of manufacturing technologies, standard analytical and bioanalytical method compendiums, cell suspensions, and cell potentiation technologies. Gene therapies for rare diseases are being rapidly adopted due to the increasing number of gene therapy pipelines and drug approvals and the introduction of novel gene therapies for the treatment of various rare diseases.
Several companies worldwide are already engaged in gene therapy and gene-modified cell therapy research, with nearly 1,000 clinical programs in development trying to predict gene therapy potential for rare genetic diseases. Achievements have been made in the treatment of multiple rare diseases, such as Hemophilia, Achromatopsia, Duchenne Muscular Dystrophy, Cystic Fibrosis, Inherited Retinal Dystrophy, Friedreich ataxia, Fragile X Syndrome, Paroxysmal Nocturnal Hemoglobinuria, Retinitis Pigmentosa, etc. To date, two gene therapies for rare diseases have been approved by the Food and Drug Administration (FDA): Zolgensma (for spinal muscular atrophy) and Luxturna (for Leber congenital melanosis). In addition, two gene therapies for rare diseases have received European Medicines Agency (EMA) approval, including Strimvelis (for severe combined immunodeficiency disease (ADA-SCID)) and Zynteglo (for β-thalassemia). Many other therapies are currently being evaluated in clinical trials.
Prospects for gene therapy for rare diseases
While gene therapy has shown significant promise in treating rare diseases, there are still many challenges that need to be addressed before it can become a widespread treatment option. One of the biggest challenges is developing efficient and cost-effective manufacturing processes to produce gene therapies. Another challenge is developing effective delivery methods that target specific cells or tissues without adverse effects.
Despite these challenges, significant progress has been made in the development of gene therapies for rare diseases, bringing hope to patients with rare diseases. With the development of second-generation sequencing technology and the spread of gene diagnosis, advances in gene editing technology, and the continued improvement in the safety and stability of drug delivery systems, it is expected that gene therapy for rare diseases will continue to achieve breakthroughs.
Reference
- Braga, L. A. M.; et al. Future of genetic therapies for rare genetic diseases: what to expect for the next 15 years? Therapeutic Advances in Rare Disease, 2022, 3: 26330040221100840.
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