Gene therapy concept render

Gene therapy is an innovative medical approach that corrects defective genes to treat or prevent diseases, offering new hope for previously incurable conditions.

About this subject

Gene therapy involves the introduction, removal, or alteration of genetic material into a patient's cells to treat a disease. This technique operates mainly in two ways: ex vivo therapy, where cells are removed, modified in the lab, and reintroduced, and in vivo therapy, where the therapeutic vector is administered directly into the body. The most common vectors are modified viruses, such as adenoviruses or lentiviruses, that carry the functional gene to target cells.

Since the first experiments in the 1990s, gene therapy has advanced dramatically. In 2017, the FDA approved tisagenlecleucel (Kymriah) for acute lymphoblastic leukemia, marking the first gene-modified cell therapy. Other approvals include voretigene neparvovec (Luxturna) for inherited retinal dystrophy and onasemnogene abeparvovec (Zolgensma) for spinal muscular atrophy. These milestones demonstrate the potential of gene therapy for rare monogenic diseases.

However, challenges remain. High costs, often exceeding $1 million per patient, limit access. Additionally, risks such as adverse immune responses, insertional mutagenesis, and off-target effects require rigorous clinical trials. Germline editing, which would alter heritable DNA, raises profound ethical questions and is banned in many countries. Despite this, research with CRISPR-Cas9 and other genome editing tools promises to expand applications to complex diseases like HIV, hemophilia, and neurodegenerative disorders.

Frequently Asked Questions

How does gene therapy work?

Gene therapy corrects defective genes by introducing healthy copies, inactivating problematic genes, or editing DNA. It typically uses viral vectors to deliver the genetic material into the patient's cells.

Which diseases can be treated with gene therapy?

Currently approved for monogenic diseases such as spinal muscular atrophy, inherited retinal dystrophy, and certain leukemias. Clinical trials explore its use in HIV, hemophilia, sickle cell disease, and neurodegenerative disorders.

What are the risks of gene therapy?

Risks include immune reactions to the viral vector, insertion of the gene in the wrong location (insertional mutagenesis), and potential long-term side effects. Rigorous clinical trials are necessary to ensure safety.