2.7 Gene therapy
Gene therapy represents a paradigm shift in medicine, moving beyond symptom management to address the root genetic causes of diseases. This approach involves introducing, removing, or changing genetic material within a patient’s cells to treat or prevent illness. As of early 2024, the field has seen remarkable growth, with over 4,000 gene, cell, and RNA therapies in development globally, and a significant number of regulatory approvals. For example, the FDA approved the first-ever CRISPR-based gene editing therapy, Casgevy, in late 2023 for sickle cell disease and transfusion-dependent beta-thalassemia. Clinical trial data for Casgevy are highly encouraging, with 96.7% of SCD patients achieving freedom from vaso-occlusive crises for at least 12 consecutive months post-treatment, underscoring the therapy’s potential for durable, transformative results (CLIMB-121 trial).
The ongoing success in trials for rare monogenic disorders like Spinal Muscular Atrophy, and Leber’s Congenital Amaurosis, validates gene therapy as a viable therapeutic modality (ASGCT.org). Promising early data for Huntington’s disease has also been reported, with a gene therapy delivered via neurosurgery showing a 75% slowing of disease progression in patients three years post-treatment (Bokinni 2025).
Despite these breakthroughs, challenges remain, primarily concerning delivery, long-term safety, and extraordinary cost. The use of viral vectors to deliver the corrective gene can occasionally trigger immune responses, as observed in some early trials.
Furthermore, the high cost of one-time treatments, such as Hemgenix for hemophilia B, which is priced at $3.5 million per dose in the US, raises significant questions about accessibility and healthcare system sustainability.
Nevertheless, the field continues to expand rapidly, with over 600 clinical trials for somatic cell gene therapy underway in the US alone, focusing on severe genetic disorders like immunodeficiencies and hemophilia, demonstrating a strong commitment to translating this technology into widespread clinical benefit.