Updated: Sep 12, 2018
Trends in Gene Therapies for Rare Diseases
Written by: Sam Bott
Edited by: Genese Hendrickson
"Doctors are men who prescribe medicines of which they know little, to cure diseases of which they know less, in human beings of whom they know nothing."
The term “gene therapy” is used frequently in healthcare discussion, but what does it really mean and what implications does this hold for patients with rare disease?
Gene therapy is an exciting new class of therapies that function simply by introducing new genetic material into the body via a vector of viral or non-viral origin. This genetic material (DNA or RNA) is then used by the cell to exert an effect on the patient, whether that is a new effect or replacing a defective function.
Gene therapy presents as a lucrative opportunity for patients with rare diseases due to the nature of the conditions. There are approximately 7,000 identified rare diseases with about 80% of these being considered monogenic; single gene mutation in cause.
Examples of monogenic rare diseases are:
- Cystic Fibrosis
- Sickle Cell Anemia
- Duchenne Muscular Dystrophy
- Spinal Muscular Atrophy
There are currently six FDA-approved gene therapies for indications ranging from Melanoma to pediatric Acute Lymphoblastic Leukemia but only one for genetic, rare diseases. In late 2017, the FDA approved Luxturna, as the first gene therapy approved for patients with inherited retinal disease due to mutations in both copies of the RPE65 gene. This marks the first time a gene therapy was approved by the FDA for a genetic mutation disorder. A handful more have been approved in Europe with one therapy developed by uniQure, Glybera, being touted as the “most expensive drug in the world” at slightly more than $1 million as a one-time treatment for an ultra-rare and genetic liposome storage disorder. Slightly less than 5 years after its approval, uniQure announced that it would not renew EMA authorization of the product, thus serving as a lesson to the healthcare community that more intuitive reimbursement structures are necessary in order to accommodate for high-cost, one-time treatments.
Distribution of these therapies will most certainly flow through inpatient/outpatient hospital as well as specialty pharmacy settings due to the variety of therapy types within this category. Classical gene therapies such as Luxturna, which do not involve biologic material, have the opportunity to fit well within the specialty pharmacy model due to the “drug-like” characteristics. Cellular gene therapies, which utilize the patient’s own cells and short turnaround times, do not fit the typical mold of a specialty pharmaceutical product due to the “procedure-like” characteristics. As more and more therapies enter the market, innovative distribution and support models will need to be implemented in order to ensure maximum access to novel gene therapies.
Safety concerns for the patient will always be a topic of great interests when it comes to new classes of therapies. Gene therapy brings the typical safety concerns of traditional therapies that are infused or injected as well as the potential for unknowns that are possible for a therapy that edits the genome. Last month, the FDA issued update on the long-term follow-up guidance for manufacturers of rare disease therapies. The agency recommended a follow-up period of up to 15 years for most types of gene therapy vector except for Adeno-associated Virus (AAV) vectors due to the lack of integration into the genome, so these patients may not experience the same follow-up burden that others may experience. Overall, the industry is taking the right path forward in providing the framework for introducing these therapies to the patients that truly need them.
Patients stand to be the biggest winners from the commercialization of gene therapy. Although gene therapy will undoubtedly be very-high cost, it offers a patient who was dealt a bad hand an opportunity to live a normal life, potentially for the first time. Manufacturers of these therapies will need to take a patient-centric approach to access and create patient-assistance to account for the high costs. The entry of new therapies to the market will always be a welcome addition to the therapeutic arsenal that patients have access to and gene therapies have the potential to offer the next big shift in treatment paradigms. We at Vivaleas are very excited to see what gene therapies will be able to offer patients, and we are committed to maximizing the promise of these therapies for patients suffering from rare diseases.