Challenges Facing the Future of Gene Therapy
Last week Cellix attended the impressive BIO International. With over 17,000 attendees it's one of the world’s biggest and best biotech and pharma conferences, celebrating the globally important innovations in biotechnology. The top companies in the field come together to share ideas and initiate collaborations, driving the future of biotech and medicine. Aside from the thousands of meetings (over 48,000!), there were also some fantastic talks from industry leaders.
These talks spanned many topics but of particular interest to us, and a focus at the conference this year, was the field of gene therapy and what the future held for it. What hurdles have to be overcome before we can fully harness the next stages of this treatment, gene therapy 2.0?
"Gene therapy has always been very dramatic. In the 90s when the first therapies were being tested in humans, we talked about altering people's fates and retooling the genetic code, the language of life.
Then there was this tragedy story where gene therapy fell apart. And then in 2010 we started to see a more positive outlook again."
- Ryan Cross
A Brief History
Despite the hype, gene therapy has had a bit of a rocky past. The first therapy approved in Europe in 2012, known as Glybera, held the top spot for the most expensive drug in the world and was not a commercial success.
The unfortunate failure of Glybera was actually an attempted comeback for gene therapy after an even worse incident in 1999. A series of mishaps during a clinical trial resulted in the unfortunate death of Jesse Gelsinger. After this the industry took a really big hit, new therapy developments ceased and much of the research in the area was put on standstill. There were clear safety issues that still needed to be met and a more fundamental understanding of the science behind the treatment was needed.
It has been a long time since then and gene therapy now is in a very different place. Thanks to dedicated researchers, the science is much further developed and the possibility of another incident like this has been essentially eliminated.
With that said, the first hurdle for the future of gene therapy is getting over its own past. Many people still associate gene therapy with unaffordable costs and life-threatening side effects. It’s going to take time and effort to let the world know that gene therapy moving toward a very different place.
"I think manufacturing needs to be the focus of the gene therapy field in the future. The ability to produce AV vectors of quality that is suitable for clinical application and also being able to produce large quantities of these viruses."
– Federico Mingozzi
Optimising manufacturing is still a big challenge for gene therapy. As it stands for many genetically modified cell therapies, a patient’s genetic sample is sent off to one of a very small number of central manufacturing plants around the world to be edited. Aside from the costs and logistics, the turnaround time at these plants can take up to several weeks!
Manufacturing is a massive bottleneck for the industry and is obviously a significant part of why gene therapy is still rarely carried out. Much work needs to be done toward optimising the process in a way that is quick, robust, reproducible and cost-effective.
For now, it appears that central manufacturing plants will be the only method of safely developing these types of gene therapies. Future therapies, however, may come from a manufacturing process that is so small and efficient, we won’t need to rely on shipping back and forth to these large plants.
Today, viral transfection is the main method of introducing new genes to treat patients; however, there are many drawbacks to it.
First of all, it has a massive influence on the manufacturing process. Manufacturing viral therapies is not currently cost-effective and virally transfecting cells with new DNA at a manufacturing plant is a lengthy process. Not to mention the intensive quality control required to make sure the therapy is safe for use.
On top of this, a large percentage of the population actually have antibodies against AAV, which is the normal vector for many gene therapies. This will greatly reduce the efficacy of treatment for large subsets of patients. For many others, the vast majority of AAVs don’t pass onto daughter cells which means that the next cells to grow may need another treatment. A very costly problem.
And finally, there is the fact that AAV viral vectors only have around 4.7kB of data carrying capacity. This is enough for most current clinical applications but it limits future therapies that require the editing of more than just a small piece of DNA.
"We are going to need all of these tools. To me that is the meaning of gene therapy 2.0. We are at the very beginning of all of this and it is a battle that is going to be fought, lessons learned, literally by disease, by tissue, by cell type over the course of decades."
– Eric David
There is still currently much to be figured out in terms of tailoring gene therapy to specific patients. For example – what dosage to use? Like drug dosages, genetic therapies will affect different people in different ways but unlike normal drugs, over-expression of a gene can have drastically different effects to overdosing on a pill. It’s very important that we figure this out.
Targeting is another issue here; getting the therapy to go where you need it. This often depends on many factors including the disease, the tissue, the cells and they can all vary from person to person. Appropriate targeting is of particular importance in the cancer space.
The vast array of things that we need gene therapy to do actually suggests that there won’t be one single method in the future. We will need as many tools as possible to properly tailor treatments to treat each individual.
Can we afford it?
The cost of gene therapy is another serious obstacle that needs to be overcome to make this type of treatment available widely to those who really need it. New innovative pricing models are being developed to try to allow for this.
Disruptive innovations in the areas featured above will definitely lower the overall price. Despite this, biologic products are always going to be expensive. Therefore, companies are looking at other ways to reach more people.
One method some companies have been discussing is to create a value-based pricing scheme. As most treatments are new there is no definite guarantee that they will be effective in the long term and given this many people can be deterred by the thought of paying so much for something that may not work. Therefore, companies are looking at different efficacy based and reimbursement models for therapies.
For example, one possible model involves paying 20% upfront and then another 20% each additional year that the therapy is still working. If the therapy stops working after a certain period of time then you get a portion of the cost reimbursed.
The most important note here is that future developments in gene therapy are not all scientific. With such ground-breaking technology, we need to develop new business models and paradigms as well.
Gene Therapy 2.0
The feeling from BIO was that we are still certainly in the early stages of gene therapy. There remains decades worth of learning to be done but with the way things are looking, there is no doubt that gene therapy stands to have a immense impact on the future of medicine.
Intensive research is still needed in many areas, spanning from delivery methods to manufacturing processes, and it will need to be specific for each therapy. In addition to the scientific side, new business models will need to be developed to facilitate a treatment unlike any we've seen before. As the field develops there will be more and more applications for the technology and gene therapy will become more accessible to the patients that desperately need it.
Photos courtesy of Biotechnology Innovation Organisation.