A patient living with a rare disease – defined as one that affects 1 in every 2,000 people 1– may understandably feel isolated. The number of patients that share their symptoms and struggles is inherently small. However, with around 7,000 different rare diseases identified to date, the rare disease community as a collective is surprisingly quite large.1,2
Dr. Gregory Costain, a medical geneticist and rare disease expert at SickKids, said that “rare diseases are collectively common.” He elaborated that “when we say rare, people immediately think it’s something that wouldn’t apply to them or their family members or their community, [but] a significant fraction of the Canadian population is impacted directly or indirectly by a rare disease.”
Indeed, the Canadian government estimates that 1 in 12 Canadians live with a rare disease.1 In the past few years, the government has launched multiple funding initiatives for rare disease research, indicating a growing awareness of this patient population at the federal level.
For example, Health Canada announced the National Strategy for Drugs for Rare Diseases in 2023, promising $1.4 billion over three years to streamline the research and treatment of rare diseases.3 The CIHR also began a Rare Disease Research Initiative in 2024 to award grants to researchers including Dr. Costain, whose ongoing clinical trial evaluates genome sequencing as a potential tool for diagnosing rare diseases.4,5
Costain is energized by these recent initiatives, and believes Canada fosters a productive environment for rare disease research. “Our public health care system […] gives [researchers] many advantages when we’re thinking about partnering with industry for clinical trials and for ultimately having drugs approved by our regulatory bodies,” Costain said.
In Canada, there are a few key agencies that help bring a drug to the market. First, Health Canada assesses the safety and efficacy of the drug. Next, groups like the Pan-Canadian Pharmaceutical Alliance settle on the drug cost. Finally, the Patented Medicine Prices Review Board (PMPRB) monitors the drug cost to ensure that it is not excessive.
Despite regulatory precautions, most rare disease therapies remain extremely expensive. Remarking on rare disease drug costs, PMPRB Executive Director Douglas Clark told the House of Commons in 2019 that “the best drug in the world won’t bring value to society if no one can afford it.” 2
One such unaffordable drug is the infamous Soliris, an antibody-based drug that treats the rare and life-threatening blood disease paroxysmal nocturnal hemoglobinuria (PNH). PNH causes extreme fatigue, anemia, and blood clots and affects only 6 in every million people a year.6 Back in 2009, the Canadian government approved Soliris as a PNH treatment, but this drug costs a staggering $700,000 per year.7
Alexion, the pharmaceutical company that developed Soliris, faced widespread criticism for the excessive price of their drug. The regulatory agency in New Zealand refused to cover the cost of Soliris in 2013, since the price was “out of line with other comparable innovative new medicines supplied by other companies.” 8
After an extensive investigation in Canada, the PMPRB capped the price of Soliris and ordered Alexion to refund $11.6 million to the Canadian government in 2022.9 The company had generated $6 billion in revenue from Soliris sales in just 8 years since the drug’s introduction.7
The Soliris case demonstrates that the rare disease research industry is highly lucrative, despite needing to market toward a small patient population. Fewer than 10% of all rare diseases have any available treatment, so each new drug treating a rare disease will likely have a monopoly.12 Indeed, Soliris is the only drug that can treat PNH, allowing Alexion to avoid competitive pricing.
Another company that has monopolized a specific rare disease treatment is PTC Therapeutics. In 2024, the company received FDA approval for Kebilidi, a gene therapy to treat an ultra-rare disease, aromatic l-amino acid decarboxylase (AADC) deficiency. AADC deficiency results from a genetic mutation that prevents the production of serotonin and dopamine, chemicals in the brain essential for controlling critical bodily functions such as breathing and moving.10 This disease currently affects fewer than 125 people worldwide, manifesting usually during the patient’s first year of life, through symptoms like seizures and an inability to hold up their head.10 As the only cure available for AADC deficiency, Kebilidi clearly dominates the market, costing over $3 million per treatment in the U.S.10
Though expensive drugs like Soliris and Kebilidi demonstrate the danger of monopolies in the rare disease industry, they also represent considerable scientific breakthroughs. As a gene-modifying treatment, Kebilidi delivers a functional copy of the AADC gene to the patient’s brain and drastically improves motor control.11 It is the first gene therapy approved to be injected directly into the brain, setting an example for treatment of more common neurological diseases.
Costain points to Kebilidi’s success as an example of how rare disease research can advance common disease research. “Because that disease [AADC deficiency] involves a specific neurotransmitter pathway in the brain, it’s now giving us the opportunity to explore re-applying or repurposing that gene therapy to treat Parkinson’s,” Costain said. “Again and again, we are seeing these examples of rare diseases allowing us to make the large problem more tractable.”
The scientific insights that rare disease research can uncover may outweigh the risk of burdening health care systems with expensive drugs. “I don’t think we will get all the insights we need to get in the more common diseases from studying rare diseases, but in our opinion, that’s been one economic and scientific justification for the investment that we are making,” Costain said.
References
- “Building a National Strategy for High-Cost Drugs for Rare Diseases: A Discussion
Paper for Engaging Canadians.” Health Canada. January 2021.
https://www.canada.ca/en/health-canada/programs/consultation-national-strategy-high-
cost-drugs-rare-diseases-online-engagement/discussion-paper.htmlCanada.ca - Canadians Affected By Rare Diseases and Disorders: Improving Access To Treatment:
Report of the Standing Committee on Health.” Canadian House of Commons. February
2019.
https://www.ourcommons.ca/Content/Committee/421/HESA/Reports/RP10349306/hesar
p22/hesarp22-e.pdf - “The National Strategy for Drugs for Rare Diseases.” Health Canada. December 2024.
https://www.canada.ca/en/health-canada/services/health-care-systems/national-
pharmacare/strategy-drugs-rare-diseases.html - “CIHR Rare Disease Research Initiative: Results.” Canadian Institutes of Health
Research. https://cihr-irsc.gc.ca/e/53941.html - Stanley, K. J., et al. (2025). TRIAGE-GS: Protocol for a randomised controlled trial of a
genomics-first approach to rare disease diagnosis for patients awaiting assessment by a
clinical geneticist. BMJ Open, 15(8), e107603. https://doi.org/10.1136/bmjopen-2025-
107603 - “Paroxysmal Nocturnal Hemoglobinuria.” Cleveland Clinic.
https://my.clevelandclinic.org/health/diseases/22871-paroxysmal-nocturnal-
hemoglobinuria - “U.S. drug company sues Canada for trying to lower cost of $700K-a-year drug.” CBC
News. September 2015. https://www.cbc.ca/news/health/u-s-drug-company-sues-canada-
for-trying-to-lower-cost-of-700k-a-year-drug-1.3242172 - “IN THE MATTER OF Alexion Pharmaceuticals Inc. and the medicine ‘Soliris.’:
Decision.” Patented Medicine Prices Review Board. September 2017. https://pmprb-
cepmb.gc.ca/CMFiles/Hearings%20and%20Decisions/Decisions%20and%20Orders/solir
is_decision_public_version.pdf - “Board Order – Soliris.” Patented Medicine Prices Review Board. June 2022.
https://www.canada.ca/en/patented-medicine-prices-review/services/hearings/decisions-
and-orders/board-order-soliris.html - “Pharmacy Focus:Kebilidi™ — New Gene Therapy for Aromatic L-amino Acid
Decarboxylase (AADC) Deficiency.” HM Life Insurance Company.
https://www.hmig.com/content/dam/hmig/en/website/documents/pdf/v1/pharmacy_focus
_kebilidi.pdf - “The dopamine reset: Restoring what’s missing in AADC deficiency.” Boston Children’s
Hospital. July 2025. https://answers.childrenshospital.org/dopamine-reset-aadc/
Annie Mitchell
