Context: The Department of Biotechnology (DBT) along with the Centre for Stem Cell Research (CSCR) at Christian Medical College (CMC), Vellore, Tamil Nadu has successfully executed a first-in-human gene therapy using lentiviral vectors to treat Haemophilia-A.
Relevance of the topic:
Prelims: Haemophilia; Gene Therapy Products; National Guidelines For Gene Therapy
Mains: Gene Therapy: Mechanism; Applications, Challenges
What is Haemophilia?
- Haemophilia is a rare genetic severe bleeding disorder caused by the deficiency of clotting Factor VIII, leading to spontaneous internal and external bleeding episodes.
- People with Haemophilia have lower levels of clotting factors (proteins in blood that help it clot). This can lead to excessive bleeding, even after a minor injury.
- It is an X-chromosome linked recessive disorder, which means that it is more common in males than in females. Females can carry the haemophilia gene, but they usually do not have symptoms unless they have two copies of the gene, one from each parent.
- India bears the world’s second-largest burden of Haemophilia.
- It is a lifelong condition with no permanent cure.
- Current treatments involve frequent Factor VIII replacement therapy (to replace the deficient clotting factor through infusions).

What is Gene Therapy?
- Gene therapy is a technique that seeks to modify or manipulate the expression of a gene or to alter the biological properties of living cells for therapeutic use (treat or cure disease).
- Gene therapies can work by several mechanisms:
- Inactivating a disease-causing gene that is not functioning properly.
- Replacing a disease-causing gene with a healthy copy of the gene.
- Introducing a new or modified gene into the body to help treat a disease.
Modes of Gene Therapy:
- Germline Gene Therapy:
- This involves modifying genes in reproductive cells (sperm or egg), which means the changes would be passed onto future generations.
- Gene editing of embryonic cells is banned across the world (and in India by ICMR Guidelines 2019)
- Somatic Gene Therapy:
- This involves modifying genes in any cell other than a reproductive cell. Changes made through somatic gene therapy affect only the treated individual and are not inherited by their offspring. This is the primary focus of current gene therapy research due to its safety and ethical considerations.

Gene Therapy Products:
- Gene Therapy Products (GTP) are biological substances designed to introduce genetic material into a patient's cells to treat or prevent a disease.
Key Components of GTP:
- Therapeutic Gene: This is the specific genetic material intended to treat the disease.
- Vector: A carrier that delivers the therapeutic gene into the target cells. This can be a virus (viral vector) or a synthetic carrier (non-viral vector).
- Other Components: Depending on the specific product, additional components may be included, such as promoters, enhancers, or markers to optimise gene expression.
Types of Gene Therapy Products:
- Plasmid DNA: Circular DNA molecules can be genetically engineered to carry therapeutic genes into human cells.
- Viral vectors:
- Viruses have a natural ability to deliver genetic material into cells, and therefore some gene therapy products are derived from viruses.
- Once viruses have been modified to remove their ability to cause infectious disease, these modified viruses can be used as vectors/vehicles to carry therapeutic genes into human cells.
- Bacterial vectors: Bacteria can be modified to prevent them from causing infectious disease and then used as vectors (vehicles) to carry therapeutic genes into human tissues.
- Patient-derived cellular gene therapy products: Cells are removed from the patient, genetically modified (often using a viral vector) and then returned to the patient.

Applications of Gene Therapy:
- Cardiovascular Diseases: Gene therapy is being explored to treat conditions like heart failure, coronary artery disease, and arrhythmias.
- Cancer: This is a major focus area for gene therapy, with various approaches being investigated, including CAR T-cell therapy, tumour suppressor gene therapy, and oncolytic viruses.
- Genetic Disorders: Gene therapy holds great promise for treating genetic diseases like cystic fibrosis, hemophilia, and muscular dystrophy by correcting the underlying genetic defect.
- Neurological Disorders: Conditions like Parkinson's disease, Alzheimer's disease, and spinal cord injuries are being targeted with gene therapy to restore neuronal function.
- Infectious Diseases: Gene therapy is being explored as a potential treatment for HIV/AIDS and other infectious diseases by enhancing the immune response.
Challenges involved in Gene Therapy:
- Delivery of genes: Effectively getting the genetic material to the target cells can be difficult.
- Immune response: The body might reject the introduced genetic material.
- Long-term effects: The long-term consequences of gene therapy are still being studied.
- Ethical Concerns: Germline Gene Therapy raises significant ethical concerns (designer babies, unintended consequences on future generations) and is currently banned in many countries.
National Guidelines For Gene Therapy:
- The Indian Council of Medical Research (ICMR) released National Guidelines for Gene Therapy Product Development and Clinical Trials in 2019. The guidelines are a crucial framework for the advancement of gene therapy in India.
- Purpose: To ensure the ethical, scientific, and safe conduct of gene therapy clinical trials and promote the development of gene therapies for treating genetic and rare diseases.
- Scope: Covers all aspects of gene therapy product development, from preclinical testing to clinical trials and post-market surveillance.
- Ethical Emphasis: Strong focus on patient safety, informed consent, and ethical considerations.
- GTAEC: Establishes the Gene Therapy Advisory and Evaluation Committee (GTAEC) to oversee gene therapy activities.
- Focus on Rare Diseases: Aims to address the unmet needs of patients with rare genetic disorders.
Mechanism used in the latest Gene Therapy to treat Haemophilia:
- The gene therapy approach uses a lentiviral vector to introduce a normal copy of the Factor VIII gene into autologous haematopoietic stem cells (HSCs).
- Lentiviral vectors are a type of viral vector that can be used to transfer genetic material into cells for gene therapy.
- These modified HSCs generate blood cells capable of producing functional Factor VIII over extended periods, thus terminating the need for repeated infusions.







