Pegzilarginase (Loargys®): What Canadians with ARG1-D Should Know
Loargys® (pegzilarginase) is an enzyme therapy for people living with Arginase 1 Deficiency (ARG1-D). In Canada, the treatment has completed major regulatory and health technology assessment milestones, including a positive final reimbursement recommendation from Canada's Drug Agency (CDA-AMC). The next phase involves reimbursement negotiations and public drug-plan funding decisions.
Positive CDA-AMC reimbursement recommendation
On August 12, 2026, CDA-AMC issued a final recommendation that Loargys be reimbursed with conditions for eligible patients living with ARG1-D.
This is an important milestone, but it does not mean public coverage is automatically available across Canada. Pricing negotiations and decisions by participating public drug plans are still required.
Recombinant human arginase 1 enzyme therapy for adults and children aged 2 years and older.
In the Phase 3 PEACE trial, 90.5% of treated participants reached normal plasma arginine levels at Week 24.
Positive final reimbursement recommendation. Pricing and public drug-plan funding decisions remain outstanding.
The Canadian access pathway
Loargys has progressed through several important steps toward Canadian treatment access.
Note: The formal pCPA negotiation status has not yet been confirmed on this page.
Understanding the reimbursement conditions
CDA-AMC recommended public reimbursement of Loargys for eligible people with ARG1-D, subject to clinical and pricing conditions.
The recommended initiation criteria include a confirmed ARG1-D diagnosis and a baseline plasma arginine level of at least 250 µmol/L.
Treatment should be prescribed and monitored by clinicians experienced in inherited metabolic diseases.
The recommendation describes an initial 24-week authorization period, followed by assessment of plasma arginine response when continued reimbursement is considered.
Families should discuss the complete renewal requirements and individual clinical circumstances with their metabolic care team.
The recommendation includes a requirement for a substantial price reduction. Public reimbursement also depends on subsequent negotiations and funding decisions.
Important: These are summaries of the reported recommendation conditions, not individual eligibility determinations. The exact clinical requirements should be checked against the official final recommendation. Public plans may establish their own implementation criteria.
Timeline: From clinical development toward Canadian access
CanPKU+ Advocacy: Community voice in the review
CanPKU+ participated in the CDA-AMC review on behalf of the community and provided feedback following the draft recommendation. Several important issues raised through that advocacy are reflected in the final guidance.
For a progressive condition, stabilization and prevention of further decline can represent meaningful treatment benefits.
Temporary increases in arginine should not automatically mean treatment has failed when the patient's broader clinical picture remains stable.
Changes in mobility, cognition and development may take 12 to 24 months or longer to become apparent.
Community language reflected in the final recommendation
Language submitted by CanPKU+ about meaningful treatment benefit, including preserving mobility, maintaining communication and participating in school and community life, is reflected in the final CDA-AMC implementation guidance.
This illustrates why patient and caregiver perspectives are essential in reimbursement decisions.
Our advocacy update compares what CanPKU+ raised during consultation with the final recommendation.
Read: What We Asked. What Changed. View the CDA-AMC Review
Patient and clinician input
Patient and clinician perspectives help decision-makers understand the impact of ARG1-D on daily life, treatment burden, unmet needs and outcomes that matter to families.
Trial information: What did the research show?
The key evidence for pegzilarginase comes from the Phase 3 PEACE trial, a randomized, double-blind, placebo-controlled, multicentre study involving children and adults with ARG1-D.
32 participants: 21 received pegzilarginase and 11 received placebo.
Plasma arginine fell from 354.0 to 86.4 µmol/L at Week 24 in the treatment group.
90.5% of treated participants reached normal plasma arginine levels versus 0% receiving placebo.
The published trial also reported functional mobility findings. The small trial population and differences between biochemical and functional outcomes are important considerations when interpreting the evidence.
Company information: Who developed Loargys?
Pegzilarginase was developed in clinical trials under the sponsorship of Aeglea BioTherapeutics, which sponsored the Phase 3 PEACE study.
The therapy is now being advanced commercially by Immedica Pharma AB, a pharmaceutical company headquartered in Stockholm, Sweden, that focuses on rare diseases.
What happens next? From recommendation to reimbursement
The positive CDA-AMC recommendation is a major milestone, but recommendation and reimbursement are not the same thing.
1. Price negotiations
The pan-Canadian Pharmaceutical Alliance (pCPA) conducts joint negotiations for participating public drug plans. A positive CDA-AMC recommendation can support consideration for this process, but does not establish that negotiations have started or concluded.
2. Public drug-plan decisions
Following applicable negotiations, participating federal, provincial and territorial public drug plans make their own decisions about funding and coverage criteria.
3. Individual access
Where public funding becomes available, patients may still need to meet clinical eligibility, specialist prescribing and renewal requirements. Timing and processes can vary by jurisdiction.
CanPKU+ will continue monitoring reimbursement developments and advocating for fair, timely and consistent treatment access for Canadians living with ARG1-D.
This page will be updated as additional pricing, reimbursement and public coverage milestones are confirmed.
Sources and further reading
- Canada's Drug Agency (CDA-AMC). Pegzilarginase reimbursement review.
- CDA-AMC. Loargys final reimbursement recommendation.
- CDA-AMC. Loargys reimbursement review - Main Report.
- CDA-AMC. Loargys reimbursement review - Supplemental Report.
- Patient and Clinician Group Input. CanPKU+ hosted document.
- CanPKU+. What We Asked. What Changed. Loargys Advocacy Update.
- Sanchez Russo R, Gasperini S, Bubb G, et al. Efficacy and safety of pegzilarginase in arginase 1 deficiency (PEACE): a phase 3, randomized, double-blind, placebo-controlled, multi-centre trial. EClinicalMedicine. 2024;68:102405.
- Immedica Pharma AB. Loargys regulatory and product information.
- National Institute for Health and Care Excellence (NICE). Pegzilarginase for treating arginase-1 deficiency in people 2 years and over (HST35).