What is gene and cell therapy?

Gene and cell therapy is the use of genes and cells to treat disease. A gene is the unit of DNA that contains hereditary information that is passed down from generation to generation. All genes together are called the genome. Genes may contain information about visible traits, such as height or eye colour. Many genes contain the instructions for RNA or protein molecules that are not visible from the outside, but perform important functions in the body's cells. Cells are the building blocks of plants and animals (including humans). They are small functional units that work together to form organs and tissues.

Genetic diseases are caused by errors, or mutations, in genes that result in a loss or change of function of  RNA or protein molecules. These mutations can be passed down from parents to children or can happen spontaneously. Humans have two copies of each gene, one inherited from their mother and one inherited from their father. Dominant mutations cause disease when only one of the copies has the mutation, while recessive mutations only cause disease if both copies are affected by the mutation. As long as an individual has one healthy copy (scientists call this wild type) of a recessive gene, they will be healthy. We call these individuals carriers. This explains why in some families some children (those with two copies of the mutation) are ill, while others (those with one wild type and one mutated copy) are healthy carriers.

Video from the US Food and Drug Administration (FDA)

Gene therapy is the use of genetic material to treat genetic diseases. This may involve adding a wild type copy of the gene (gene addition) or altering a gene with mutation to the wild type gene (gene editing). The treatment may take place outside of the body (ex vivo) or inside the body (in vivo). To get the gene into the genome inside the cells, modified viruses or other vectors are used.

Cell therapy is the use of cells that are taken either from the patient themselves or a donor to treat diseases. Cells used for cell therapy are often stem cells, cells that can mature into different types of specialised cells. Cells used for cell therapy may or may not be genetically altered. It is sometimes easier to remove cells from the body, treat them with gene therapy and then place them back than treating the cells inside the body. This is the case for gene therapy for blood disorders. Gene and cell therapy therefore often go together, which is reflected in the name of our society.

For more information on stem cells, please see the EuroStemCell website. Further informative videos about gene therapy include those by gene therapy companies AGCT and bluebird bio.

Current developments in gene and cell therapy

All medicines and treatments go through stringent testing in the lab (pre-clinical research) and in small groups of patients (clinical research). Enormous progress has been made in gene and cell therapy research since the the 1970s and 1980s. The first clinical successes in patients were in the 1990s and the first treatments were approved for general use in the past decade. Gene and cell therapy products approved for use in patients now include: Glybera, Strimvelis, Yescarta, Kymriah.

Gene and cell therapy technology is evolving rapidly and we are now closer than ever to gene and cell therapies for many different diseases. However, gene and cell therapies remain experimental medicines and much more research is needed before many of these therapies are available to all patients everywhere.

Some developments that have been crucial for gene and cell therapies are gene editing (particularly CRISPR, which is more efficient and more precise than zinc finger nucleases and TALENs), induced pluripotent (iPS) cells and safer viral vectors for gene delivery.

For more information on gene editing, please see this video from the Royal Society. More information on iPS cells is available on the EuroStemCell website.

Clinical trials

Clinical trials are an extremely important part of research. In taking part in a clinical trial a patient is informing future treatment of the disease they suffer from and may gain early access to potential treatments. However, the treatments are not guaranteed to work and there may be risks involved in taking part in a clinical trial. We recommend that you discuss the potential risks and benefits with a trusted qualified physician before enrolling in a clinical trial.

For more information on regulation of medicines, please see the EMA website (EU) and the FDA website (USA). Current clinical trials are listed on the EU Clinical Trials Register and ClinicalTrials.gov (USA).

Patient perspective

In 2017 we celebrated our 25th anniversary as a society. To illustrate the progress that gene and cell therapy has made since ESGCT was founded in 1992, we made made an overview of patients who have been treated with these therapies and the effect this had on their lives.

Our members and others all over the world work hard everyday to change many more lives over the next 25 years and beyond. Many disorders for which gene therapies are being developed have patient organisations. Patient organisations are often involved in patient advocacy and providing information and peer support. They may also be involved in research or fundraising for research. Most patient organisations can be easily found through their websites and social media presence and some can be found on our Gene and Cell Therapy Community Heatmap.