Gene therapy concept render

Gene therapy is a technique that modifies genes to treat or prevent diseases, offering hope for previously incurable conditions.

About this subject

Gene therapy is an innovative medical approach aimed at correcting genetic defects responsible for hereditary or acquired diseases. It works by introducing, removing, or altering genetic material within the patient's cells. Since the first experiments in the 1970s, the field has evolved significantly, with advances such as viral vectors (e.g., adeno-associated viruses) and gene editing technologies like CRISPR-Cas9. The first gene therapy treatment approved in the United States occurred in 2017 for a form of leukemia using CAR-T cells. Since then, regulatory approvals have expanded to include diseases such as spinal muscular atrophy and certain hereditary blindnesses.

Gene therapy can be administered in two main ways: ex vivo, where cells are modified outside the body and reintroduced, or in vivo, where the vector is injected directly into the patient. The technique faces challenges such as efficient gene delivery to target cells, immune response, and durability of effects. However, the therapeutic potential is immense: treatments already exist for hemoglobinopathies, severe combined immunodeficiencies, and some cancers. An estimated over 2,000 gene therapy clinical trials are ongoing worldwide.

Interestingly, the earliest cases of gene therapy date back to 1990, when a girl with adenosine deaminase (ADA) deficiency received modified cells. Although the treatment was not curative, it paved the way for future research. Today, gene therapy is considered one of the most promising frontiers of personalized medicine, with potential to treat not only monogenic diseases but also complex conditions like diabetes and cardiovascular diseases. The high cost (often exceeding $1 million per patient) and ethical issues related to germline editing remain topics of intense debate.

Frequently Asked Questions

How does gene therapy work?

Gene therapy corrects defective genes using vectors (such as inactivated viruses) to deliver a functional copy of the gene, or by directly editing DNA with tools like CRISPR-Cas9. Cells can be modified outside the body (ex vivo) or directly in the patient (in vivo).

Which diseases can already be treated with gene therapy?

Currently, approved treatments exist for spinal muscular atrophy, certain leukemias, hereditary blindness (e.g., Leber congenital amaurosis), and sickle cell disease, among others. Many clinical trials are ongoing for conditions like hemophilia and muscular dystrophy.

Is gene therapy safe?

Safety has improved with more precise vectors and immune management. However, risks remain including immune reactions, unwanted genomic insertion, and unknown long-term effects. Regulatory approval requires rigorous clinical trials.