Gene therapy may become the major way to prevent or treat diseases in the future and replace all the medical procedures we are following at present. However, it is still in the initial stages. Scientists have to conduct a lot of research in this field before it can be used for the benefit of humankind.
Gene Therapy – Understanding the Basics
Gene therapy is an experimental medical procedure used to prevent or treat diseases with the help of genes. In the future, doctors may use this procedure to insert healthy genes into the cells of a patient or remove/modify faulty genes from cells to cure disorders instead of using surgical procedures, chemotherapy, drugs, or any of the medical procedures currently in use.
Right now, medical scientists are experimenting with a variety of approaches to gene therapy, including:
- Replacing disease-causing genes with healthy copies of the same genes
- Inactivating or removing faulty genes that are no longer able to function
- Introducing brand new genes into cells to cure diseases
It is quite clear that gene therapy has the potential to become the number one treatment option for several diseases, especially certain types of cancer, genetic disorders, and viral infections. But it is still in the experimental stage. Dealing with genes is not without risks and humankind has to research gene therapy for many more decades before it becomes safe for use.
Currently, medical scientists are experimenting with gene therapy as a cure for incurable disorders only.
Let us consider the example of pituitary tumours.
Usually, pituitary tumours are benign and slow-growing but may invade surrounding tissues and cause serious problems such as blindness and headache. Moreover, deficiency or hyper-secretion of pituitary hormones may cause major health issues that require expensive medical treatment.
The medical world has been researching pituitary tumours for the past two or three decades, but the condition is still incurable. In the future, gene therapy may prove to be an effective way to cure pituitary tumours.
Developments in the Last Five Years
Gene therapy has witnessed the following developments in the last five years:
- After several decades of research and experimentation, therapies like oligonucleotide-based therapies, in-vivo gene therapies, and cell therapies have received approval. They are now used to treat disorders like cancer, inherited blindness, neuromuscular diseases, and many others.
- The above-mentioned therapies have saved the lives of several patients. Also, they also form the basis on which researchers can develop treatments for other life-threatening and incurable disorders.
- For example, the success of gene transfer procedures led to the development of several AAV-based therapies involving the delivery of genes to skeletal muscles and the liver to treat Hemophilia I and Duchenne Muscular Dystrophy II, respectively.
- And here is another example. Research in adoptive cell immunotherapy was expanded to studies in modifying hematopoietic stem cells, which further enabled the development of therapies for several genetic disorders like Beta Thalassemia and Sickle Cell Disease. The European Union has recently approved these therapies, and the US is currently reviewing them.
Gene Editing Therapies
Gene therapy is not limited to gene delivery alone but also to gene editing, which involves the treatment of disorders by modifying genome sequences. Research on gene editing began in 2010 to find a way to stop HIV infection of T cells, but gene-editing therapies showed signs of efficacy only last year when it was used to treat Beta Thalassemia and Sickle Cell Disease. The method was not only successful but also safe, and this success has paved the way for several on-going clinical trials of in-vivo gene editing.
The National Institutes of Health recently announced that it would provide $190 million over six years to fund a Somatic Cell Genome Editing Consortium, which will address a variety of challenges to using in-vivo genome editing for treating medical disorders. The findings of this consortium are expected to accelerate the progress of research in gene editing therapies in the following decade.
At present, gene-editing procedures involve the use of nuclease-based systems to remove DNA strands and stimulate the pathway of DNA repair to obtain the desired changes in the genome sequence. Although gene-editing technology is in a stage of infancy, several next-generation editing technologies have come up to improve the accuracy, efficiency, applicability, and specificity of gene editing in the treatment of a variety of diseases.
The example, prime editing and base editing are brand new editing technologies that make it easier to alter genome sequences without breaking DNA strands and relying on repair pathways. Editing technologies targeting RNA enable reversible and temporary modification of genome sequences, making the gene-editing procedure safer and more efficient.
We also have to mention epigenome editing technologies, which come with benefits like reversibility and sustainability.
Challenges to Gene Therapy Research
Although research in gene and cell therapy is moving forward at a rapid pace, these therapies are unable to receive the required safety and efficacy certificates from regulatory bodies.
According to current regulatory models, a treatment procedure has to be used successfully on a large number of patients before it can receive the efficacy and safety stamp. These regulations do not apply to a curative technology that can be used to address a faulty gene found in one patient or a small number of patients.
Also, gene therapy is risky. Doctors cannot insert a gene directly into your cells. They have to deliver these genes to your cells through a vector. Usually, these vectors are viruses owing to their ability to recognize certain cells and carry the genetic material directly to those cells.
Before injecting these viruses into the patient, researchers remove the disease-causing genes from them and replace them with genes required to stop the disorder. When this is done, you have to face the following risks:
- Your immune system will attack the viruses leading to undesired effects like organ failure and inflammation.
- The viruses may carry the genetic material to more than one type of cells, damaging healthy cells and causing illness.
- Once inside your body, the viruses may regain their original ability to cause diseases.
- If the genetic material reaches the wrong place in your DNA, it may lead to the development of tumours.
Wrapping it up, we can say that gene therapy is exciting and has the potential to change the way we treat diseases in the next few decades. It has also inspired new research in areas like cell reprogramming, synthetic biology, functional genomics, and many others, which will revolutionize the way we perceive diseases and their treatment.
When it comes to gene therapy, we have a long way to go before we can call it a safe way to treat diseases.