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Sephience (sepiapterin):

What Canadians with PKU Should Know

Sephience is a treatment for sepiapterin-responsive phenylketonuria (PKU). Health Canada has already authorized Sephience for sale in Canada, but regulatory approval is only one step in the broader access pathway. Public reimbursement decisions are made separately, and those decisions can still take additional time after approval.[1][2][3]

Drug type
A sepiapterin therapy used with a phenylalanine-restricted diet for adults and pediatric patients 1 month of age and older with sepiapterin-responsive PKU.[1][2]
Clinical finding
In the Phase 3 APHENITY study, blood phenylalanine fell by 63% with sepiapterin compared with 1% with placebo in the primary analysis set after 6 weeks.[4]
Canada status
Health Canada issued a Notice of Compliance on October 7, 2025. Health Canada's product database lists Sephience as marketed, with an original market date of December 1, 2025.[1][2]
Jump to:
Timeline Trial information Company information Access in Canada Resources References
Timeline: From clinical development to Canada
September 30, 2021 to April 3, 2023
The Phase 3 APHENITY study was conducted across 34 sites globally. The trial evaluated orally administered sepiapterin in children and adults with PKU.[4]
October 2024
Results from APHENITY were published in The Lancet, reporting a statistically significant reduction in blood phenylalanine in the sepiapterin group compared with placebo.[4]
July 28, 2025
The U.S. Food and Drug Administration approved Sephience for hyperphenylalaninemia in adults and pediatric patients 1 month of age and older with sepiapterin-responsive PKU, to be used with a phenylalanine-restricted diet.[6]
October 7, 2025
Health Canada issued a Notice of Compliance for Sephience. The submission was listed as a New Drug Submission with priority review.[1]
December 1, 2025
Health Canada's Drug Product Database lists Sephience as marketed, with an original market date of December 1, 2025.[2]
December 10, 2025
PTC Therapeutics Canada ULC publicly announced Health Canada approval and stated that Sephience was commercially available in Canada.[5]
Trial information: What did the research show?

The key evidence for Sephience comes from the Phase 3 APHENITY trial, an international, randomized, double-blind, placebo-controlled study in children and adults with PKU.[4]

Study design
Phase 3, randomized, double-blind, placebo-controlled trial conducted across 34 sites globally.[4]
Enrollment
156 participants were evaluated in Part 1. Of these, 114 were identified as sepiapterin-responsive. The primary analysis set in Part 2 included 98 participants, split evenly between placebo and sepiapterin.[4]
Primary biochemical result
After 6 weeks in the primary analysis set, blood phenylalanine decreased by 63% with sepiapterin compared with 1% with placebo.[4]
Extension findings
Company-reported extension data described durable treatment effect and improved dietary phenylalanine tolerance over time.[5]

Health Canada's Summary Basis of Decision states that the overall benefit-harm-uncertainty profile for Sephience was favourable for the approved indication in sepiapterin-responsive PKU.[3]

Company information: Who developed and manufactures it?

Sephience is made by PTC Therapeutics International Limited, which is the manufacturer listed in Health Canada's Notice of Compliance and Drug Product Database records.[1][2]

Health Canada's Summary Basis of Decision describes sepiapterin as a metabolic precursor of tetrahydrobiopterin (BH4), an important co-factor involved in phenylalanine hydroxylase activity.[3]

PTC states that Sephience is approved in multiple regions, including Canada, the United States, and the European Economic Area.[5][6]

Access in Canada: What approval means and what may still happen next

Sephience is approved in Canada. Health Canada issued a Notice of Compliance on October 7, 2025, and the product is listed as marketed in Health Canada's database.[1][2]

What we know so far

  • Health Canada authorized Sephience for adults and pediatric patients 1 month of age and older with sepiapterin-responsive PKU, used with a phenylalanine-restricted diet.[1][3]
  • Health Canada's product database lists Sephience as marketed, with an original market date of December 1, 2025.[2]
  • PTC announced on December 10, 2025 that Sephience was commercially available in Canada.[5]
  • Regulatory approval and public reimbursement are separate processes in Canada. Coverage decisions may still vary by province or territory and may take additional time.[7]

What access can still depend on

Even after a drug is approved, routine public access often depends on several additional steps:

1. Market launch
2. Reimbursement review
3. Pricing discussions
4. Provincial or territorial funding decisions
5. Local implementation

This page is intended to explain the process in a neutral, informational way. It is not medical advice and should not replace guidance from a metabolic specialist or care team.

Resources and updates

The items below may help families, caregivers, and clinicians follow the Canadian access landscape and learn more about Sephience.

CanPKU+ may continue to collect community experiences for educational and awareness purposes, including stories shared in written, audio, or video format where appropriate.

Why this matters for Canadians living with PKU

PKU is a lifelong metabolic condition that can require careful dietary management and regular monitoring. Additional treatment options may be meaningful for some individuals and families, especially when they support better phenylalanine control or help expand dietary flexibility.[4][5]

For Canadians, understanding the difference between regulatory approval, commercial availability, and public reimbursement can help set realistic expectations about how access may unfold.

This page is intended as an educational and awareness resource and should not replace individualized medical advice from a metabolic specialist or care team.

Sources and references
  1. Health Canada. Notice of Compliance Information: SEPHIENCE. Notice of Compliance date: October 7, 2025.
    https://health-products.canada.ca/noc-ac/nocInfo?no=36125
  2. Health Canada. Drug Product Database: SEPHIENCE product information. Listed as marketed; original market date December 1, 2025.
    https://health-products.canada.ca/dpd-bdpp/info?code=106476&lang=eng
  3. Health Canada. Summary Basis of Decision for Sephience.
    https://dhpp.hpfb-dgpsa.ca/review-documents/resource/SBD1766001787668/
  4. Muntau A, Longo N, Ezgu F, et al. Effects of oral sepiapterin on blood Phe concentration in a broad range of patients with phenylketonuria (APHENITY): results of an international, phase 3, randomised, double-blind, placebo-controlled trial. The Lancet. 2024;404:1333-1345.
    https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2824%2901556-3/fulltext
    https://clinicaltrials.gov/study/NCT05099640
  5. PTC Therapeutics Canada ULC. PTC Therapeutics Announces Health Canada Approval of Sephience (sepiapterin) for the Treatment of Children and Adults Living with Phenylketonuria (PKU). December 10, 2025.
    https://www.newswire.ca/news-releases/ptc-therapeutics-announces-health-canada-approval-of-sephience-tm-sepiapterin-for-the-treatment-of-children-and-adults-living-with-phenylketonuria-pku--894716546.html
  6. U.S. Food and Drug Administration. Sephience (sepiapterin) approval package and labeling. Approval date: July 28, 2025.
    https://www.accessdata.fda.gov/drugsatfda_docs/nda/2025/219666Orig1s000Approv.pdf
    https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/219666s000lbl.pdf
  7. Canada's Drug Agency (CDA-AMC). Reimbursement Reviews. Overview of how public reimbursement review fits after Health Canada approval.
    https://www.cda-amc.ca/reimbursement-reviews