Gene Therapy

Genes are the blueprints of the human body. They instruct the body’s cells on how to make proteins critical to their function. Many diseases and disorders are caused by the faulty expression of proteins from faulty or missing genes.

What is gene therapy?

Gene therapy turns what has long only been wishful thinking into a reality: addressing an inherited or acquired disease at its root cause by using genetic material as a treatment. This can mean, for instance, the removal or change of a faulty or missing gene, or the introduction of genetic material into certain cells of the patient. In this sense, gene therapy represents a paradigm-shift in how healthcare systems can address diseases as it has the potential to address areas of high unmet medical need, where current treatment options so far can only provide limited or insufficient care for patients.

Science and technology

For introducing genetic material, gene therapies add a functional copy of the gene that is faulty or missing to the patient’s cells. This copy will then promote the production of the desired protein in the patient’s body, which can be for example an enzyme, a blood coagulation factor or other. This way, the therapeutic gene helps the cells to function correctly, and the functional protein can be restored. For this kind of gene therapy the genetic material is only introduced to some cells in the patient’s body, like liver cells for example. 

To be successful and ensure targeted and safe delivery of the genetic material, the gene therapy product requires three components, including a vector, a promoter, and the transgene. Unlike small molecules, for example, genes cannot simply be ingested or injected, since they would be cleared or broken down after entering the bloodstream unprotected. Instead, genes require a vector, a kind of shuttle that gets them to the targeted cell. The most common vectors used in current FDA-approved gene therapy treatments are  modified viruses. Though it might sound paradoxical at first, viruses are perfect for this – after all, they are nature’s experts at delivering genetic material to specific cells. Before using the virus as a vector, its DNA is removed, leaving only the shell, also known as capsid, which is then filled with copies of the healthy genetic material. Viruses used that way do not cause diseases but make for suitable gene therapy vectors. Beyond viral vectors, researchers are also investigating other ways to deliver gene therapies, such as lipid nanoparticles. 

Of the other two components, the transgene holds all the genetic information for the cells to deliver the therapeutic response. Once packed into the vector, it travels to the target cell and delivers the correct instructions. The promoter, on the other hand, is needed to drive the expression of the transgene in the target cells. It is basically a piece of DNA sitting in front of the therapeutic transgene and can be designed to act like a switch, regulating the activity of the transgene in selected tissues of interest.

Whether viral or not, once the shuttles are carrying their genetic load, they can be injected into the body of the patient. There they find the intended cell and deliver the genes, which then make the cell function as it should – potentially stopping an illness for many years, ending it, or even reversing it with only one treatment.