Pegzilarginase

ARG1-D is an inherited metabolic disease characterized by deficiency of the arginase 1 enzyme and associated with the persistent elevation of plasma arginine. LOARGYS provides an exogenous source of the deficient human arginase 1 enzyme activity in patients with ARG1-D and reduces plasma arginine by converting it to urea and ornithine.

• LOARGYS is indicated for the treatment of hyperargininemia in adult and pediatric patients 2 years of age and older with Arginase 1 Deficiency (ARG1-D), in conjunction with dietary protein restriction. This indication is approved under accelerated approval based on reduction of plasma arginine [see Clinical Studies ( 14 )] .

• None. None.contraindicated

• Administer LOARGYS under the supervision of a health care provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis. ( 2.1 ) • Initiate LOARGYS in a healthcare setting with appropriate medical monitoring and support measures, including access to cardiopulmonary resuscitation equipment. ( 2.1 ) • Consider pre‑medication with antihistamines. ( 2.1 ) • Obtain a baseline plasma arginine concentration prior to initiating treatment. ( 2.1 ) • Recommended starting dosage of LOARGYS is 0.1 mg/kg administered by intravenous infusion once weekly. ( 2.2 ) • Maximum recommended dosage is 0.2 mg/kg once weekly. ( 2.2 ) • See the Full Prescribing Information for recommended titration and maintenance dosage and recommended plasma arginine level testing during treatment. ( 2.2 ) • After eight weeks of once weekly intravenous LOARGYS, patients may be switched to once weekly subcutaneous LOARGYS at the same dosage of intravenous therapy. ( 2.4 ) • See Full Prescribing Information for dosage and administration modifications due to hypersensitivity reactions. ( 2.5 ) • See Full Prescribing Information for instructions on preparation, storage, and administration. ( 2.7 , 2.8 , 2.9 , 2.10 ) 2.1 Recommendations Prior to LOARGYS Treatment • Administer LOARGYS under the supervision of a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis [see Warnings and Precautions ( 5.1 )] .

Hypersensitivity : If a severe hypersensitivity reaction occurs, discontinue LOARGYS and immediately initiate appropriate medical treatment, including epinephrine. ( 5.1 ) 5.1 Hypersensitivity Reactions Including Anaphylaxis Life-threatening hypersensitivity reactions, including anaphylaxis, have occurred in patients treated with enzyme replacement therapies (ERTs) including LOARGYS. Hypersensitivity reactions that were mild to moderate in severity occurred in 13% (6/48) of LOARGYS-treated patients in clinical trials [see Adverse Reactions ( 6 )] . Hypersensitivity reactions have included facial swelling, rash, flushing and dyspnea. The reactions generally occurred with the first few doses, but may also occur later in treatment. LOARGYS-treated patients who developed anti-drug antibodies (ADA) generally had a greater incidence of hypersensitivity reactions compared to those who did not develop ADA [see Adverse Reactions ( 6.1 )] . Anaphylaxis has occurred during the early course of ERT and after extended duration of ERT. Administration of LOARGYS should be supervised by a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis. Consider pre‑medication with an antihistamine. Corticosteroids can be considered in patients who have previously developed a hypersensitivity reaction. Initiate LOARGYS in a healthcare setting with appropriate medical monitoring and support measures, including access to cardiopulmonary resuscitation equipment.

The following adverse reactions are described below and elsewhere in the labeling: • Hypersensitivity Reactions [see Warnings and Precautions ( 5.1 )] . Most common adverse reactions (>10%) are vomiting, pyrexia, infusion associated reactions and constipation. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Immedica at toll-free phone 1-844-627-4687 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of LOARGYS was evaluated in a randomized, double-blind, placebo-controlled trial in pediatric and adult patients with ARG1-D (Trial 1). Additional safety information was derived from Trial 2, a Phase 1 open-label trial that evaluated 16 patients between the ages of 5 to 31 years to assess safety, PK and PD of LOARGYS, and Trial 3, an open-label extension including 14 patients from Trial 2. Adverse Reactions from Trial 1 (Double-Blind Period) A total of 21 patients between the ages of 2 and 28 years of age, at enrollment, received intravenous LOARGYS dosages up to 0.2 mg/kg once weekly and 11 patients received placebo for 24 weeks [see Clinical Studies ( 14 )] . Table 1 summarizes the adverse reactions reported in ≥ 2 LOARGYS-treated patients and at a higher incidence in LOARGYS-treated patients compared to placebo-treated patients in Trial 1.

8.1 Pregnancy Risk Summary There are no available data on LOARGYS use in pregnant females to evaluate for a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. In animal reproduction studies, intravenous administration of pegzilarginase-nbln to pregnant rats and rabbits during organogenesis resulted in maternal toxicity with associated increased incidence of fetal growth deficiencies (see Data ) . The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data In an embryofetal development study in pregnant rats with normal circulating arginine levels, intravenous pegzilarginase-nbln was administered throughout organogenesis at 0.1, 0.3, and 1 mg/kg/dose on gestation days 6, 11, and 16.

Metabolism

The maximum plasma concentration (C max ) and area under the plasma concentration-time curve (AUC) of pegzilarginase-nbln at steady state following intravenous and subcutaneous administration of LOARGYS at the 0.1 mg/kg weekly dosage in adults and pediatric patients with ARG1‑D are summarized in Table 2 . Pegzilarginase-nbln exposures increased in an approximately dose-proportional manner at the recommended dosages.

• Feb 23, 2026BLABLA761211Immedica Pharma Ab

1. 1Ammonia Increased2100%
2. 2Hepatic Enzyme Increased2100%
3. 3Hyperammonaemia2100%

The 5 most recently updated of 5 ClinicalTrials.gov registrations naming Pegzilarginase as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Pegzilarginase in Subjects <24 Months Old With Arginase 1 Deficiency
  Completed · Phase 3 · Interventional · 3 enrolled · Immedica Pharma AB
  NCT06582524updated 2026-05-22
• Efficacy and Safety of Pegzilarginase in Patients With Arginase 1 Deficiency
  Completed · Phase 3 · Interventional · 32 enrolled · Aeglea Biotherapeutics
  NCT03921541updated 2024-11-19
• A Study of AEB1102 (Pegzilarginase) in Patients With Arginase I Deficiency
  Completed · Phase 2 · Interventional · 14 enrolled · Aeglea Biotherapeutics
  NCT03378531updated 2023-07-27
• A Study of Safety of Weekly Subcutaneous Pegzilarginase in Subjects With Arginase 1 Deficiency
  Terminated · Phase 3 · Interventional · 3 enrolled · Aeglea Biotherapeutics
  NCT05676853updated 2023-07-27
• Pegzilarginase and Pembrolizumab for Extensive Disease Small Cell Lung Cancer
  Completed · Phase 1 · Phase 2 · Interventional · 68 enrolled · Aeglea Biotherapeutics
  NCT03371979updated 2021-11-04

Frequently asked questions

How does Pegzilarginase work?

ARG1-D is an inherited metabolic disease characterized by deficiency of the arginase 1 enzyme and associated with the persistent elevation of plasma arginine. LOARGYS provides an exogenous source of the deficient human arginase 1 enzyme activity in patients with ARG1-D and reduces plasma arginine by converting it to urea and ornithine.

What is Pegzilarginase used for?

According to FDA labeling, Pegzilarginase carries indications including: LOARGYS is indicated for the treatment of hyperargininemia in adult and pediatric patients 2 years of age and older with Arginase 1 Deficiency (ARG1-D), in conjunction with dietary protein restriction. This indication is approved under accelerated approval based on reduction of plasma arginine [see Clinical Studies ( 14 )] .. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Pegzilarginase?

Pegzilarginase is classified as Enzymes, Enzymatic Activity.

What are the brand names for Pegzilarginase?

Pegzilarginase is marketed under brand names including Loargys.

What are the contraindications for Pegzilarginase?

Pegzilarginase labeling lists contraindications including: None. None.. Always consult the full prescribing information and a clinician.