Breaking through: Gene therapy and the potential for treatment of rare diseases

The ability to manipulate genes for the prevention and treatment of human disease has been a quest for science and medicine for decades. This pursuit has enjoyed successes and failures, progress, and unfulfilled hype. But in recent years, breakthroughs in the development of gene therapies, coupled with advancements in diagnostics, have led to innovative treatment strategies, particularly for those with rare diseases.

While the number of people with an individual disease may be small (e.g., fewer than 1 in 100,000), the Canadian Organization for Rare Disorders estimates that as many as 1 in 12 Canadians are affected by a rare disorder.

Most rare diseases arise from mutations in a single gene, making them more attractive targets for gene therapies than common, genetically complex diseases. There have been promising reports from some clinical trials, but despite the potential for treating rare diseases, gene therapies have raised difficult ethical, legal, and social questions. For instance, because the potential market for these treatments is small, companies may be less inclined to invest in the costly R&D necessary to develop them. It is also harder to generate the depth of data necessary for pre-approval testing, and for post-market surveillance because of the smaller patient pools to draw from. This may lengthen time to market and reduce the capacity of regulators to offer assurances of safety and efficacy.

Moreover, treatment affordability is a concern, which is exacerbated by the already high costs of gene therapy development: some patient groups may have more money to finance the development of new therapies, while in other cases, new drugs or therapies are out of reach for the majority of patients because of price. For example, Spinraza (used to treat Spinal Muscular Atrophy, which affects approximately 1 in 6,000 babies in Canada) is one of just three gene therapies currently approved for use in Canada, but costs hundreds of thousands of dollars a year, leaving public and private payers across the country grappling with difficult decisions.

In Budget 2019, the Canadian federal government pledged to develop a national strategy for high-cost drugs for rare diseases to help Canadians get better access to the effective treatments they need.

Given that so few gene therapies have made their way to the bedside, it is not surprising that less attention has been given to the challenges and impediments relating to access and affordability than for the issues that arise in discovery research and early development. But access and availability issues are now before us.

This is the context for a request from the National Research Council, which asked the CCA to undertake an assessment on the key legal, ethical, social, and policy challenges specific to the approval and use of somatic gene and engineered cell therapies in Canada. Our assessment will inform Canadian policy on this complex issue. The final report will be released in 2020.

Eric M. Meslin, PhD, FCAHS
President and CEO, Council of Canadian Academies