We all have people living with diabetes and heart ailments in our families getting "treated" with medicines all these days. And when they are getting "treated", in reality, they are being managed of their disorders. For e.g. A diabetic patient is being managed with drugs, diet and exercise so that her blood sugar levels are around the normal levels most of the time. Similarly a heart patient is being managed with drugs, diet and exercise to keep his cholesterol levels, blood pressure, Sodium levels etc. at optimum levels. That's going to change in the years to come... Going forward a patient could be treated with a gene therapy, which would replace/repair a mutant gene thereby slowing or even stopping the progression of the disease.... yes you heard it right! There are technologies being developed successfully now that can stop the progression of a disease, at least those disease that are mapped to a mutant gene or an allele, with just ONE dose of a gene therapy!!!
Genes are made up of DNA, which are blueprints to build enzymes and proteins that make our body work. As far as we know, humans have between 20,000 and 25,000 genes. We typically get two copies of each gene from our parents. They influence everything from the color of our hair to our immune system, but genes aren’t always built correctly. A small adjustment to them can change how our proteins work, which then alter the way we breathe, walk or even digest food. Genes can change as they go through inherited mutations, as they age, or by being altered or damaged by chemicals and radiation.
How Gene therapy works?
As mentioned earlier, gene therapy may be able to help in cases of those disease where it is mapped to a gene mutation. For e.g. Huntington's disease, Spinal Muscular Atrophy, cancers, diabetes, heart disease etc. Gene therapy is the introduction, removal or change in genetic material—specifically DNA or RNA—into the cells of a patient to treat a specific disease. The transferred genetic material changes how a protein—or group of proteins—is produced by the cell.
Now how do we introduce this genetic material in to human body so that they penetrate in to our cells and reach the gene? This new genetic material or working gene is delivered into the cell by using a vector (or a carrier). Typically, viruses are used as vectors because they have evolved to be very good at sneaking into and infecting cells. But in this case, their motive is to insert the new genes into the cell. Some types of viruses being used are typically not known to cause disease and other times the viral genes known to cause disease are removed. Regardless of the type, all viral vectors are tested many times for safety prior to being used.
Currently for many diseases the treatments are limited to only symptomatic treatments using currently available drugs. For e.g. drugs are typically used to manage disease or infection symptoms to relieve pain, inflammation, cognition etc., while gene therapy targets the cause of the disease. It is not provided in the form of a pill, inhalation or surgery, it is provided through an injection or IV.
Economic Implications:
Since these include very high research, development and manufacturing costs, gene therapies are going to be very expensive when compared to the current treatment costs. Novartis launched Zolgensma for Spinal Muscular Atrophy (SMA) in 2018 for a whooping $2.1 million for one dose! Again, you heard it right. Is this sticker shock that bad as it sound? It depends... Let us see what are the options. If not for a gene therapy, an SMA patient would be treated with symptomatic treatments managing the symptoms and the patient would die in a span of 3 - 4 years time since diagnosis. The health care cost during this time would include the symptomatic treatment costs, hospital costs, care giver costs since the patient would soon become dependent as the disease progresses, assisted living costs etc. followed by death in 3-4 years time. Instead, Zolgensma demonstrated slowing of disease progression and life year extension to around 12 years! It is indeed a massive step towards providing advanced care for many under treated, rare and ultra rare diseases.
Gene therapies with such price tags definitely have limitations when it comes to accessibility to patients. Even in the developed markets like the US, EU5 and Japan, where these high value products are initially getting launched, payers / insurance companies are figuring out ways to evaluate the cost benefit analysis for these medications in the proper manner.
According to a latest report by American Biopharmaceutical Companies group,
- there are 5 disease currently treated by cell and gene therapies
- more than 100 disease are being explored for cell and gene therapies
- there are about 300 cell and gene therapies in development
- development led by cancers, neurological disorders and blood disorders
Ongoing excitement is assured in this space as it might transform the way we diagnose, treat, pay and follow-up some of the deadly diseases in the days to come.