Quebec's INESSS Recommends Against Reimbursement of Loargys
October 19, 2026 | Advocacy | Treatment Access
Quebec's Institut national d'excellence en santé et en services sociaux (INESSS) has recommended against public reimbursement of Loargys (pegzilarginase), a treatment for people living with arginase 1 deficiency (ARG1-D).
This is a recommendation, not a final government coverage decision. Quebec's Minister of Health has not yet announced a final decision.
What is ARG1 deficiency?
ARG1 deficiency is an ultra-rare inherited metabolic disorder belonging to the family of urea cycle disorders (UCDs).
People with ARG1 deficiency cannot properly break down arginine, an amino acid found in protein. Elevated arginine levels can contribute to progressive neurological complications, including difficulties with walking, muscle stiffness, developmental challenges and seizures.
Traditional management involves dietary protein restriction, specialized medical nutrition and medications to help manage complications. Despite these interventions, controlling arginine levels can remain challenging.
What makes Loargys different?
Loargys is an enzyme replacement treatment designed to reduce excess arginine in the bloodstream.
It is used in patients aged two years and older and is administered weekly by intravenous or subcutaneous injection.
Clinical evidence reviewed by INESSS demonstrated that Loargys substantially reduced blood arginine levels. However, questions remain about how these improvements translate into better long-term mobility, neurological outcomes and survival.
Why did INESSS recommend against reimbursement?
INESSS acknowledged the treatment's ability to reduce arginine concentrations but raised concerns about its cost relative to the clinical benefits demonstrated to date.
The agency estimated approximately $25.4 million in additional public expenditure over three years for four patients.
This illustrates a recurring challenge in rare disease treatment assessment: therapies may demonstrate important biological improvements while longer-term clinical outcomes remain difficult to establish because patient populations are exceptionally small.
What happens next?
The recommendation will be considered as part of Quebec's reimbursement decision-making process.
Until a final decision is announced, it is important not to interpret the INESSS recommendation as a definitive refusal of coverage by the Quebec government.
CanPKU+ perspective
CanPKU+ advocates for equitable and timely access to appropriate treatments for people living with phenylketonuria (PKU), urea cycle disorders (UCDs), homocystinuria (HCU), maple syrup urine disease (MSUD) and related inherited metabolic disorders.
Ultra-rare diseases present unique challenges for traditional drug assessment processes. Small patient populations, limited long-term evidence and high treatment costs can complicate reimbursement decisions.
Patient and caregiver experiences, clinical expertise and the consequences of untreated or inadequately managed disease are important considerations in these assessments.
CanPKU+ will continue following developments concerning Loargys and opportunities for meaningful patient involvement in reimbursement discussions.
Official source:
INESSS: Loargys (ARG1-D), October 2026 recommendation
This article is provided for information and advocacy awareness. Treatment decisions should be discussed with the patient's metabolic healthcare team.
