Aldurazyme (Laronidase): Uses, Dosage & Side Effects
A recombinant enzyme replacement therapy for the treatment of non-neurological symptoms of mucopolysaccharidosis type I (MPS I)
Aldurazyme (laronidase) is a recombinant enzyme replacement therapy (ERT) approved for the long-term treatment of mucopolysaccharidosis type I (MPS I). MPS I is a rare, inherited lysosomal storage disorder caused by a deficiency of the enzyme alpha-L-iduronidase, leading to progressive accumulation of glycosaminoglycans (GAGs) throughout the body. Aldurazyme replaces this missing enzyme, helping to reduce GAG storage and improve non-neurological symptoms including lung function, joint mobility, and hepatosplenomegaly. It is administered as a weekly intravenous infusion under medical supervision.
Quick Facts: Aldurazyme
Key Takeaways
- Aldurazyme is the first and only approved enzyme replacement therapy for MPS I, addressing the underlying cause of this rare genetic disease by replacing the deficient alpha-L-iduronidase enzyme.
- Treatment is administered as a weekly intravenous infusion (100 U/kg body weight) over approximately 3–4 hours, either in a clinical setting or at home for stable patients under professional supervision.
- Clinical trials have demonstrated improvements in forced vital capacity (lung function), 6-minute walk test distance, liver and spleen size, and joint range of motion in treated patients.
- Infusion-associated reactions are common but generally mild to moderate; premedication with antihistamines, antipyretics, or corticosteroids is recommended to reduce the risk. Serious anaphylactic reactions have been reported rarely.
- Aldurazyme does not cross the blood-brain barrier and therefore does not treat the neurological manifestations of severe MPS I (Hurler syndrome). For patients with significant CNS involvement, hematopoietic stem cell transplantation remains the treatment of choice.
What Is Aldurazyme and What Is It Used For?
Aldurazyme (laronidase) is a biotechnology-derived medicine developed for the treatment of mucopolysaccharidosis type I (MPS I), a rare inherited lysosomal storage disorder. MPS I encompasses a clinical spectrum that includes three historically recognized phenotypes: Hurler syndrome (MPS I-H, the most severe form), Hurler-Scheie syndrome (MPS I-H/S, intermediate severity), and Scheie syndrome (MPS I-S, the attenuated form). Today, clinicians increasingly classify MPS I along a severity continuum rather than as distinct subtypes, though the terminology remains in widespread use.
The underlying cause of MPS I is a deficiency or complete absence of the lysosomal enzyme alpha-L-iduronidase (IDUA), encoded by the IDUA gene on chromosome 4p16.3. This enzyme is essential for the degradation of two glycosaminoglycans (GAGs): dermatan sulfate and heparan sulfate. When alpha-L-iduronidase is absent or insufficiently active, these GAGs accumulate progressively in lysosomes throughout the body, leading to cellular and organ dysfunction. The disease is inherited in an autosomal recessive pattern, meaning both parents must carry a mutated copy of the IDUA gene for a child to be affected. The estimated incidence of MPS I is approximately 1 in 100,000 live births, though this varies by population.
Clinical manifestations of MPS I are multisystemic and progressive. They include coarsening of facial features, skeletal abnormalities (dysostosis multiplex), joint stiffness and contractures, hepatosplenomegaly (enlargement of the liver and spleen), cardiac valve disease, corneal clouding, hearing loss, upper airway obstruction, and recurrent respiratory infections. In severe forms, progressive intellectual disability and central nervous system involvement are also present. Without treatment, patients with severe MPS I typically do not survive beyond the first decade of life, while those with attenuated forms may survive into adulthood with varying degrees of morbidity.
Aldurazyme was the first enzyme replacement therapy (ERT) approved for MPS I. It was granted marketing authorization by the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) in 2003 under orphan drug designation, reflecting the rarity of MPS I. Laronidase is produced by recombinant DNA technology in Chinese hamster ovary (CHO) cells. The recombinant enzyme is glycosylated with mannose-6-phosphate residues, which enables it to be taken up into cells via mannose-6-phosphate receptors and delivered to lysosomes, where it can catalyze the breakdown of accumulated GAGs.
The pivotal phase III clinical trial of Aldurazyme demonstrated statistically significant improvements in two primary endpoints: forced vital capacity (FVC, a measure of lung function) and the 6-minute walk test (6MWT, a measure of exercise capacity). Secondary endpoints showed reductions in liver volume, urinary GAG excretion, and improvements in joint range of motion. These benefits were sustained in long-term extension studies, with data supporting continued efficacy over more than 10 years of treatment. However, it is important to understand that Aldurazyme primarily addresses the somatic (non-neurological) manifestations of MPS I. Because intravenously administered laronidase does not cross the blood-brain barrier in therapeutically meaningful amounts, it is not effective for treating the cognitive decline or other central nervous system complications associated with severe MPS I (Hurler syndrome).
What Should You Know Before Receiving Aldurazyme?
Contraindications
Aldurazyme is contraindicated in patients with a known severe or life-threatening hypersensitivity (allergy) to laronidase or to any of the excipients in the formulation. Prior anaphylactic reaction to laronidase is an absolute contraindication unless the treating physician determines that the potential benefits clearly outweigh the risks and appropriate desensitization and resuscitation measures are in place. It is important to note that while most infusion-associated reactions are manageable, some can be severe and potentially life-threatening, particularly in patients with pre-existing upper airway obstruction.
Warnings and Precautions
Serious allergic reactions, including anaphylaxis, have been reported during or up to 3 hours after Aldurazyme infusion. Some of these reactions were life-threatening and included severe respiratory distress, throat swelling, low blood pressure, and low blood oxygen levels. Emergency resuscitation equipment and trained personnel must be immediately available during all infusions. If a severe reaction occurs, the infusion must be stopped immediately and appropriate medical treatment initiated.
Before starting Aldurazyme treatment, your physician should carefully evaluate your overall health status, with particular attention to respiratory and cardiovascular function. The following precautions and considerations apply:
- Upper airway obstruction: Patients with MPS I frequently have pre-existing narrowing of the upper airways due to GAG deposition. These patients may be at increased risk of severe respiratory complications during infusion reactions, including bronchospasm, respiratory arrest, and airway obstruction. Close monitoring and airway management capabilities are essential.
- Infusion-associated reactions: Reactions occurring during or shortly after the infusion are common. Symptoms may include fever, chills, headache, nausea, vomiting, rash, flushing, elevated blood pressure, and increased heart rate. If such reactions occur, the infusion should be slowed or temporarily interrupted, and your doctor will decide on appropriate management and whether treatment can continue.
- Premedication: Your doctor may prescribe premedication with antihistamines (such as diphenhydramine or cetirizine), antipyretics (such as paracetamol/acetaminophen), and/or corticosteroids to reduce the risk and severity of infusion-associated reactions. This is particularly important for patients who have experienced previous reactions.
- Antibody formation: Most patients treated with Aldurazyme develop antibodies (immunoglobulin G, IgG) against laronidase. The development of antibodies is a common immunological response to exogenous proteins. In some cases, these antibodies may reduce the clinical efficacy of treatment. Some patients may also develop IgE antibodies, which are associated with a higher risk of anaphylaxis. Your doctor will monitor your antibody status as part of routine clinical care.
- Cardiac and pulmonary compromise: Patients with significant underlying cardiac or pulmonary disease may be more vulnerable to the fluid load and hemodynamic changes associated with intravenous infusion. Careful monitoring of vital signs throughout the infusion is recommended.
Caution should be exercised when administering Aldurazyme to patients experiencing an acute febrile or respiratory illness. The risks of the infusion should be weighed against the benefits, and the treating physician may decide to postpone the infusion until the patient has recovered. Febrile illness may increase the risk of infusion-associated reactions.
Drug Interactions
There is limited formal drug interaction data for Aldurazyme. However, based on the mechanism of action and enzyme kinetics, the following considerations apply:
- Chloroquine and procaine: These drugs have the potential to inhibit intracellular uptake of laronidase. Chloroquine inhibits lysosomal enzyme activity by raising intralysosomal pH, while procaine may interfere with mannose-6-phosphate receptor-mediated endocytosis. Co-administration of these drugs with Aldurazyme should be avoided, as they could reduce the therapeutic efficacy of enzyme replacement therapy.
- Other medications: No other significant drug interactions have been identified. Aldurazyme is a protein therapeutic that is metabolized through normal protein catabolism and does not interact with the cytochrome P450 enzyme system. Therefore, it is unlikely to affect the metabolism of conventional small-molecule drugs. However, always inform your healthcare team about all medications, supplements, and herbal remedies you are taking.
Pregnancy and Breastfeeding
There is insufficient clinical experience regarding the use of Aldurazyme during pregnancy. Animal reproduction studies are not always predictive of human response, and the available preclinical data do not provide conclusive evidence of safety or harm. Aldurazyme should not be administered during pregnancy unless the treating physician determines that the potential benefit clearly justifies the potential risk to the fetus. Women of childbearing potential should discuss family planning with their metabolic disease specialist.
It is not known whether laronidase is excreted in human breast milk. Given the protein nature of the drug, some passage into breast milk is theoretically possible. The benefits of breastfeeding should be weighed against the potential risks to the nursing infant. The decision to discontinue breastfeeding or to discontinue Aldurazyme treatment should be made in consultation with the treating physician, taking into account the importance of the therapy for the mother and the potential impact on the infant.
No data are available regarding the effects of Aldurazyme on human fertility. Preclinical reproductive toxicology studies have not shown adverse effects on fertility at therapeutic doses, but comprehensive human data are lacking.
Driving and Operating Machinery
No formal studies on the effects of Aldurazyme on the ability to drive or operate machinery have been conducted. Given that the infusion is administered intravenously over several hours in a clinical setting, patients should assess how they feel after each infusion before driving or engaging in activities requiring alertness. Some infusion-associated reactions (such as dizziness or headache) may temporarily impair these abilities.
Each 5 ml vial of Aldurazyme contains approximately 30 mg of sodium (equivalent to 1.5% of the WHO-recommended maximum daily sodium intake for an adult). When calculating the total sodium load, consider the number of vials required per infusion, which depends on the patient's body weight. Patients on sodium-restricted diets should discuss this with their healthcare team.
How Does Aldurazyme Interact with Other Drugs?
Because Aldurazyme (laronidase) is a recombinant human protein, its metabolism follows standard protein degradation pathways rather than hepatic cytochrome P450 (CYP)-mediated metabolism. This means it is unlikely to have pharmacokinetic interactions with most conventional small-molecule drugs. Nevertheless, there are specific pharmacodynamic interactions that healthcare professionals should be aware of when managing patients receiving Aldurazyme.
Known Interactions
| Interacting Drug | Effect | Clinical Advice |
|---|---|---|
| Chloroquine | May inhibit intracellular uptake and lysosomal activity of laronidase by raising intralysosomal pH, potentially reducing the therapeutic benefit of enzyme replacement therapy | Avoid co-administration. If chloroquine therapy is medically necessary, discuss with your metabolic disease specialist to assess the risk-benefit balance. |
| Procaine | May interfere with mannose-6-phosphate receptor-mediated endocytosis, potentially reducing cellular uptake of laronidase and diminishing treatment efficacy | Avoid concurrent use. If local anesthesia is required, use alternative agents that do not interfere with lysosomal enzyme uptake. |
Premedication Interactions
Aldurazyme is frequently co-administered with premedication agents including antihistamines (e.g., diphenhydramine, cetirizine), antipyretics (e.g., paracetamol/acetaminophen, ibuprofen), and corticosteroids (e.g., hydrocortisone, methylprednisolone). These combinations are well-established in clinical practice and no adverse interactions have been reported. The premedication regimen is an integral part of safe Aldurazyme administration and should not be omitted without medical guidance.
Patients with MPS I frequently require additional medications for their various organ system complications, including cardiac medications, respiratory treatments, and pain management. No clinically significant interactions between Aldurazyme and these supportive therapies have been identified in post-marketing surveillance or clinical studies. However, all patients should ensure their metabolic disease specialist and other healthcare providers are fully informed of all concurrent medications to enable comprehensive monitoring.
Some patients who develop significant anti-drug antibodies (particularly IgE antibodies leading to anaphylaxis) may require immunomodulatory protocols to enable continued Aldurazyme treatment. These protocols, which may include medications such as methotrexate, rituximab, or other immune-modulating agents, should only be prescribed and managed by experienced metabolic disease specialists in collaboration with clinical immunologists.
What Is the Correct Dosage of Aldurazyme?
Aldurazyme dosing is weight-based and consistent across all age groups and MPS I phenotypes. The drug must be diluted before administration and given as an intravenous infusion by or under the supervision of a healthcare professional experienced in the management of patients with MPS I or other lysosomal storage disorders. Treatment should be initiated as early as possible in the disease course for maximum benefit.
Standard Dosing (All Patients)
Intravenous Infusion
Dose: 100 U/kg body weight once weekly
Initial infusion rate: 2 U/kg/hour
Rate escalation: May be increased every 15 minutes if tolerated, doubling the rate at each step
Maximum infusion rate: 43 U/kg/hour
Total infusion time: Approximately 3–4 hours
Dilution: Diluted in 0.9% sodium chloride solution; total infusion volume of 100 ml (body weight ≤20 kg) or 250 ml (body weight >20 kg)
Children and Adolescents
The dosage of Aldurazyme for children and adolescents is the same as for adults: 100 U/kg body weight once weekly. There is no requirement for dose adjustment based on age. Clinical trials and post-marketing experience have included pediatric patients from infancy onwards. Early initiation of treatment in young children is associated with better long-term outcomes, as GAG accumulation and organ damage are less advanced at earlier stages of the disease. In clinical practice, enzyme replacement therapy may be initiated as soon as the diagnosis of MPS I is confirmed, regardless of the patient's age.
Pediatric patients, particularly infants and young children, may require careful attention to infusion volume and rate due to their smaller blood volume. The dilution volume is adjusted based on body weight (100 ml for patients weighing 20 kg or less). Infusion rates should be increased cautiously, with close monitoring of vital signs throughout the procedure.
Elderly Patients
Due to the natural history of severe MPS I, there is limited clinical experience with Aldurazyme in elderly patients. However, patients with attenuated MPS I (Scheie syndrome and Hurler-Scheie syndrome) may survive into adulthood and older age, and these patients may benefit from enzyme replacement therapy. No specific dose adjustment for elderly patients has been established. The standard dose of 100 U/kg once weekly is recommended, with careful monitoring for infusion-associated reactions and attention to any concurrent cardiac, respiratory, or renal impairment that may affect the patient's ability to tolerate the infusion.
Home Infusion
After an initial period of infusions in a clinical setting (typically several months during which the patient's tolerance is established), the treating physician may consider transitioning to home infusion for stable patients who have not experienced significant infusion-associated reactions. Home infusion must be administered by a trained healthcare professional with access to emergency medical equipment. The decision to allow home infusion should be made jointly by the patient, their family or caregivers, and the metabolic disease specialist, taking into account the patient's clinical status, prior infusion history, and the availability of appropriate home care support.
Missed Dose
If a scheduled Aldurazyme infusion is missed, contact your treating physician as soon as possible to arrange a replacement infusion. Enzyme replacement therapy works by continuously replacing the deficient enzyme; missed doses may lead to re-accumulation of GAGs and potential worsening of symptoms. The infusion should be rescheduled at the earliest convenient time. Do not attempt to administer a double dose to compensate for a missed infusion.
Overdose
There are no reports of overdose with Aldurazyme. If an excessive dose is administered or the infusion rate is too fast, patients may experience nausea, abdominal pain, headache, dizziness, and dyspnea (difficulty breathing). In such cases, the infusion should be immediately stopped or the rate significantly reduced, and the patient should be monitored. Supportive care should be provided as needed. Contact your healthcare provider for guidance on whether and how to resume treatment.
Preparation and Administration
Aldurazyme must be prepared using aseptic technique by a healthcare professional. Each vial is for single use only. The concentrate must be diluted in 0.9% sodium chloride infusion solution before administration. The required number of vials is determined by the patient's body weight. Vials should be removed from refrigeration approximately 20 minutes before use to allow them to reach room temperature (below 30°C). Each vial should be visually inspected for particles or discoloration before use; the solution should be clear to slightly opalescent and colorless to pale yellow. The diluted solution should be administered using an infusion set equipped with a 0.2 μm in-line filter.
What Are the Side Effects of Aldurazyme?
As with all biological medicines, Aldurazyme can cause side effects, although not everyone experiences them. The majority of adverse effects are infusion-associated reactions, meaning they occur during the infusion or within the hours following it. The frequency and severity of these reactions tend to decrease with continued treatment as patients develop tolerance to the infused enzyme. Clinical trial data and post-marketing surveillance provide a comprehensive picture of the safety profile of Aldurazyme.
Very Common
- Headache: One of the most frequently reported symptoms during infusion
- Nausea: Feeling sick, usually mild and self-limiting
- Abdominal pain: Stomach discomfort during or after infusion
- Rash: Skin eruption, usually mild and transient
- Arthropathy: Joint disease or joint-related symptoms
- Arthralgia: Joint pain, may affect various joints
- Back pain: Discomfort in the back region
- Pain in extremity: Pain in arms or legs
- Flushing: Redness and warmth of the skin, particularly the face
- Pyrexia: Fever, commonly associated with infusion reactions
- Chills: Shivering and feeling cold
- Tachycardia: Increased heart rate
- Blood pressure increased: Transient elevation during infusion
- Infusion site reactions: Swelling, redness, fluid accumulation, discomfort, itching, pale skin, discoloration, or warmth at the infusion site
Common
- Body temperature increased: Measured elevated temperature beyond normal range
- Paraesthesia: Tingling or numbness sensation
- Dizziness: Feeling lightheaded or unsteady
- Cough: New or worsened cough during or after infusion
- Dyspnea: Difficulty breathing or shortness of breath
- Vomiting: Being sick
- Diarrhea: Loose or frequent stools
- Angioedema: Rapid swelling under the skin in areas such as the face, throat, arms, and legs; can be life-threatening if affecting the throat
- Urticaria: Hives or itchy welts on the skin
- Pruritus: Itching of the skin
- Alopecia: Hair loss
- Cold sweat, hyperhidrosis: Excessive sweating
- Myalgia: Muscle pain
- Pallor: Pale skin appearance
- Cold extremities: Cold hands or feet
- Feeling hot, feeling cold: Altered temperature sensation
- Fatigue: Tiredness and lack of energy
- Influenza-like illness: Flu-like symptoms following infusion
- Injection site pain: Pain at the needle insertion site
- Restlessness: Feeling agitated or unable to relax
- Anaphylactic reaction: Severe allergic reaction with potential drop in blood pressure, breathing difficulty, and swelling of face and throat
- Facial oedema: Swelling of the face
Frequency Not Known
- Hypersensitivity: Allergic reactions of varying severity
- Bradycardia: Abnormally slow heart rate
- Hypertension: Abnormally high blood pressure
- Laryngeal oedema: Swelling of the voice box, causing breathing difficulty
- Cyanosis: Bluish discoloration of the skin due to low blood oxygen
- Tachypnea: Abnormally rapid breathing
- Erythema: Skin redness
- Infusion site extravasation: Leakage of drug into surrounding tissue, potentially causing local damage
- Respiratory failure: Lungs unable to adequately oxygenate the blood
- Laryngeal oedema: Swelling of the throat and airway
- Stridor: High-pitched breathing sound indicating airway narrowing
- Bronchospasm: Sudden constriction of the airways causing breathing difficulty
- Lip swelling, tongue swelling: Localized swelling that may affect breathing or swallowing
- Peripheral oedema: Swelling of ankles and feet due to fluid retention
- Drug-specific antibody: Immune response producing antibodies against laronidase
- Neutralizing antibody: Antibodies that may reduce the effectiveness of the drug
Stop the infusion and seek emergency medical attention immediately if you experience any of the following during or after an Aldurazyme infusion: severe difficulty breathing or wheezing; swelling of the face, lips, tongue, or throat; a sudden drop in blood pressure (feeling faint, dizzy, or light-headed); rapid or irregular heartbeat; bluish skin color; severe rash with blistering; or loss of consciousness.
The development of anti-laronidase antibodies is an expected immunological response and occurs in the majority of treated patients. In clinical trials, approximately 90% of patients developed IgG antibodies against laronidase within the first few months of treatment. The presence of antibodies does not necessarily correlate with reduced clinical efficacy or increased adverse events, although some patients with high antibody titers may show diminished response to therapy. A small proportion of patients develop IgE-mediated antibodies, which are associated with a higher risk of anaphylactic reactions. Regular antibody monitoring is recommended as part of the ongoing clinical management of patients receiving Aldurazyme.
The frequency and severity of infusion-associated reactions generally decrease with continued treatment, as most patients develop immunological tolerance over time. If you experience any side effects during or after your infusion, report them to your healthcare team so that appropriate management can be implemented. You can also report suspected side effects directly to your national pharmacovigilance authority, such as the MHRA Yellow Card scheme in the UK, the FDA MedWatch program in the US, or the EMA EudraVigilance system in Europe.
How Should You Store Aldurazyme?
Proper storage of Aldurazyme is critical to maintaining the stability and potency of this biological medicine. Unlike small-molecule drugs, protein therapeutics are sensitive to temperature, light, and mechanical stress. The following storage guidelines apply:
- Unopened vials: Store in a refrigerator at 2°C to 8°C (36°F to 46°F). Do not freeze. Do not use vials that have been frozen. Store in the original packaging to protect from light.
- Pre-infusion preparation: Remove the required number of vials from the refrigerator approximately 20 minutes before use to allow them to reach room temperature (below 30°C / 86°F). Do not heat artificially.
- Diluted solution: From a microbiological safety perspective, the diluted solution should be used immediately. If immediate use is not possible, the diluted solution may be stored for up to 24 hours at 2°C to 8°C, provided that dilution was performed under controlled and validated aseptic conditions.
- Incompatibilities: Aldurazyme must not be mixed with other medicinal products in the same infusion. Use only 0.9% sodium chloride solution for dilution.
- Expiry date: Do not use Aldurazyme after the expiry date (EXP) stated on the vial label. The expiry date refers to the last day of the stated month.
- Child safety: Keep all medicines out of the sight and reach of children.
- Disposal: Each vial is for single use only. Any unused product or waste material should be disposed of in accordance with local requirements for biological waste.
Healthcare professionals administering Aldurazyme should visually inspect each vial before use. The solution should be clear to slightly opalescent and colorless to pale yellow. Do not use vials that contain visible particles, are cloudy, or show signs of discoloration. Any vials that do not meet these criteria should be discarded according to appropriate waste disposal guidelines.
What Does Aldurazyme Contain?
Aldurazyme is supplied as a concentrate for solution for infusion. Understanding its composition is important for healthcare professionals preparing and administering the drug, as well as for patients and caregivers who should be aware of all ingredients in case of allergies or dietary considerations.
Active Ingredient
Laronidase: Each milliliter of concentrate contains 100 units (U) of laronidase. Each vial contains 5 ml, providing a total of 500 U of laronidase per vial. Laronidase is a recombinant form of human alpha-L-iduronidase, produced by recombinant DNA technology in Chinese hamster ovary (CHO) cells. It is a glycoprotein with a molecular weight of approximately 83 kDa. The enzyme is manufactured using advanced biotechnology processes to ensure purity, potency, and consistency.
Inactive Ingredients (Excipients)
The excipients in Aldurazyme serve to stabilize the protein, maintain appropriate pH, and ensure compatibility with intravenous infusion:
- Sodium chloride: Provides isotonicity and helps maintain the stability of the protein solution.
- Sodium phosphate monobasic monohydrate: Buffering agent that helps maintain the pH of the solution within the optimal range for protein stability.
- Sodium phosphate dibasic heptahydrate: Additional buffering component for pH control.
- Polysorbate 80: A non-ionic surfactant that prevents protein aggregation and adsorption to container surfaces, helping to maintain the integrity and bioactivity of laronidase.
- Water for injections: Highly purified water that serves as the solvent for the concentrate.
Each 5 ml vial of Aldurazyme contains approximately 30 mg of sodium, equivalent to 1.5% of the WHO-recommended maximum daily sodium intake for an adult. The total sodium load per infusion depends on the number of vials required (based on patient body weight) plus the sodium from the 0.9% saline diluent. This should be taken into consideration for patients on a controlled sodium diet.
Appearance and Packaging
Aldurazyme is supplied as a clear to slightly opalescent, colorless to pale yellow solution in single-use glass vials. The vials are available in pack sizes of 1, 10, or 25 vials per carton, although not all pack sizes may be marketed in every country. The marketing authorization holder is Sanofi B.V. (Amsterdam, Netherlands), and the product is manufactured by Genzyme Ireland Ltd. (Waterford, Ireland).
Frequently Asked Questions About Aldurazyme
Aldurazyme (laronidase) is used to treat mucopolysaccharidosis type I (MPS I), a rare inherited lysosomal storage disorder. It is an enzyme replacement therapy that provides the missing enzyme alpha-L-iduronidase, which is needed to break down glycosaminoglycans (GAGs) in the body. Without this enzyme, GAGs accumulate in cells and tissues, causing progressive damage to organs including the lungs, heart, joints, liver, and spleen. Aldurazyme treats the non-neurological manifestations of MPS I across all disease phenotypes (Hurler, Hurler-Scheie, and Scheie syndromes).
Aldurazyme is given once weekly as an intravenous infusion. Each infusion takes approximately 3 to 4 hours to complete. The dose is 100 U per kilogram of body weight. The infusion is started at a slow rate and gradually increased if the patient tolerates it well. Treatment is typically lifelong, as stopping therapy would lead to re-accumulation of glycosaminoglycans and worsening of symptoms. Initial infusions are given in a clinical setting, but stable patients may transition to home infusion under professional supervision.
No, Aldurazyme does not effectively treat the neurological (brain) symptoms of MPS I. When given intravenously, laronidase does not cross the blood-brain barrier in significant amounts. Therefore, it cannot address the cognitive decline, developmental delay, or central nervous system GAG storage that occurs in severe MPS I (Hurler syndrome). For patients with significant neurological involvement, hematopoietic stem cell transplantation (HSCT) is the recommended treatment, ideally performed before the age of 2 years. Some treatment centers use a combination of HSCT and Aldurazyme ERT. Research into intrathecal enzyme delivery and gene therapy for CNS-targeted treatment is ongoing.
Infusion reactions are side effects that occur during or shortly after the Aldurazyme infusion. They are common, especially during the early months of treatment, and can include symptoms such as fever, chills, headache, nausea, rash, flushing, and changes in heart rate or blood pressure. Most reactions are mild to moderate and tend to decrease in frequency and severity over time. They are managed by slowing or temporarily stopping the infusion, and by administering premedication (antihistamines, paracetamol, and/or corticosteroids) before future infusions. In rare cases, serious anaphylactic reactions may occur, which require immediate emergency treatment.
Yes, Aldurazyme is generally considered a lifelong therapy for patients with MPS I. Because the underlying genetic defect means the body cannot produce adequate alpha-L-iduronidase on its own, external enzyme replacement must be continued indefinitely to maintain the clinical benefits and prevent re-accumulation of glycosaminoglycans. Stopping treatment has been associated with clinical deterioration in case reports. The long-term safety and efficacy of Aldurazyme have been documented in extension studies spanning more than a decade. Any decision to modify or discontinue treatment should be made in close consultation with a specialist in metabolic diseases.
Yes, home infusion of Aldurazyme is possible for patients who have demonstrated good tolerance to the treatment over an extended period of infusions in a clinical setting. The treating physician will assess whether home infusion is safe and appropriate based on the patient's clinical status, infusion history, and access to trained home healthcare support. A qualified healthcare professional must administer the infusion at home, and appropriate emergency equipment and medications must be available. If any adverse reactions occur during a home infusion, the healthcare professional can stop the infusion and initiate appropriate treatment. Home infusion can significantly improve quality of life by reducing the burden of weekly hospital visits.
References
This article is based on current international medical guidelines, regulatory documents, and peer-reviewed research. All sources meet evidence level 1A standards.
- European Medicines Agency (EMA). Aldurazyme (laronidase) – Summary of Product Characteristics. EMA; 2024. Comprehensive regulatory document covering indications, dosing, contraindications, and safety data for the European market.
- U.S. Food and Drug Administration (FDA). Aldurazyme (laronidase) – Prescribing Information. FDA; 2024. Full prescribing information including pharmacokinetics, clinical trial data, and post-marketing safety updates.
- Wraith JE, Clarke LA, Beck M, et al. Enzyme replacement therapy for mucopolysaccharidosis I: a randomized, double-blinded, placebo-controlled, multinational study of recombinant human alpha-L-iduronidase (laronidase). The Journal of Pediatrics. 2004;144(5):581-588. doi:10.1016/j.jpeds.2004.01.046
- Clarke LA, Wraith JE, Beck M, et al. Long-term efficacy and safety of laronidase in the treatment of mucopolysaccharidosis I. Pediatrics. 2009;123(1):229-240. doi:10.1542/peds.2007-3847
- Muenzer J, Wraith JE, Clarke LA. Mucopolysaccharidosis I: management and treatment guidelines. Pediatrics. 2009;123(1):19-29. doi:10.1542/peds.2008-0416
- Jameson E, Jones S, Remmington T. Enzyme replacement therapy with laronidase (Aldurazyme) for treating mucopolysaccharidosis type I. Cochrane Database of Systematic Reviews. 2019;(6):CD009354. doi:10.1002/14651858.CD009354.pub4
- de Ru MH, Boelens JJ, Das AM, et al. Enzyme replacement therapy and/or hematopoietic stem cell transplantation at diagnosis in patients with mucopolysaccharidosis type I: results of a European consensus procedure. Orphanet Journal of Rare Diseases. 2011;6:55. doi:10.1186/1750-1172-6-55
- Giugliani R, Federhen A, Rojas MV, et al. Mucopolysaccharidosis I, II, and VI: Brief review and guidelines for treatment. Genetics and Molecular Biology. 2010;33(4):589-604. doi:10.1590/S1415-47572010005000093
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023. Reference for global essential medicines including enzyme replacement therapies for lysosomal storage disorders.
- Sifuentes M, Doroshow R, Hoft R, et al. A follow-up study of MPS I patients treated with laronidase enzyme replacement therapy for 6 years. Molecular Genetics and Metabolism. 2007;90(2):171-180. doi:10.1016/j.ymgme.2006.08.007
Editorial Team
This article has been written and reviewed by the iMedic medical editorial team according to our strict editorial standards. Our team consists of licensed physicians, pharmacists, and medical researchers with expertise in clinical pharmacology, metabolic medicine, and rare diseases.
Content developed by iMedic's medical writing team based on current international guidelines (EMA, FDA, ACMG) and peer-reviewed pharmacological and clinical research on enzyme replacement therapy.
Independently reviewed and fact-checked by the iMedic Medical Review Board, comprising board-certified specialists in clinical pharmacology, metabolic medicine, and rare diseases.
All medical claims are supported by Level 1A evidence (systematic reviews, meta-analyses, and randomized controlled trials) following the GRADE evidence framework.
iMedic receives no commercial funding from pharmaceutical companies. All content is editorially independent with no conflicts of interest.