| The majority of the related adverse events in the clinical trials were classified as infusion-associated reactions (IARs), experienced by 53% of the patients in the Phase 3 study (treated for up to 4 years) and 35% of the patients in the under 5 study (up to 1 year of treatment). Some of the IARs were severe. Over time the number of these reactions decreased. The most frequent adverse drug reactions (ADRs) were: headache, nausea, abdominal pain, rash, arthralgia, backpain, pain at extremity, flushing, pyrexia, infusion site reactions, blood pressure increased, oxygen saturation decreased, tachycardia and chills.ADRs to Aldurazyme reported during the Phase 3 study and its extension in a total of 45 patients age 5 years and older and treated up to 4 years are listed below using the following categories of frequency: very common ( 1/10); common ( 1/100 to <1/10), uncommon ( 1/1,000 to <1/100), rare ( 1/10,000 to <1/1,000), very rare (<1/10,000) and not known (cannot be estimated from the available data). Due to the small patient population, an ADR reported in a single patient is classified as common.| MedDRASystem Organ Class | MedDRAPreferred Term | Frequency | | Immune system disorders
| Anaphylactic reaction
| Common
| | Psychiatric disorders
| Restlessness
| Common
| | Nervous system disorders
| Headache
| Very common
| | Paraesthesia, dizziness
| Common
| | Cardiac disorders
| Tachycardia
| Common
| | Vascular disorders
| Flushing
| Very common
| | Hypotension, pallor, peripheral coldness
| Common
| | Respiratory, thoracic and mediastinal disorders
| Respiratory distress, dyspnoea, cough
| Common
| | Gastrointestinal disorders
| Nausea, abdominal pain
| Very common
| | Vomiting, diarrhoea
| Common
| | Skin and subcutaneous tissue disorders
| Rash
| Very common
| | Angioneurotic edema, swelling face, urticaria, pruritus, cold sweat, alopecia, hyperhidrosis
| Common
| | Musculoskeletal and connective tissue disorders
| Arthropathy, arthralgia, back pain, pain in extremity
| Very common
| | Musculoskeletal pain
| Common
| | | | | | | | | General disorders and administration site conditions
| Pyrexia, infusion site reaction
| Very common
| | Chills, feeling hot, feeling cold, fatigue, influenza like illness
| Common
| | Investigations
| Body temperature increased, oxygen saturation decreased
| Common
| A single patient with pre-existing airway compromise developed a severe reaction three hours from the start of the infusion (at week 62 of treatment) consisting of urticaria and airway obstruction, requiring tracheostomy. This patient tested positive for IgE.Post-marketing experience of infusion associated reactions revealed reporting of cyanosis, hypoxia, tachypnoea, pyrexia, vomiting, chills and erythema, in which some of these reactions were severe. Additionally, a few patients who had a prior history of severe MPS I- related upper airway and pulmonary involvement, experienced severe reactions including bronchospasm, respiratory arrest, and facial oedema (see section 4.4).There have been reports of extravasation in patients treated with Aldurazyme. Paediatric population ADRs to Aldurazyme reported during a Phase 2 study in a total of 20 patients, under 5 years of age and mainly of the severe phenotype, treated up to 12 months are listed below. ADRs were all mild to moderate in severity. | MedDRASystem Organ Class | MedDRA Preferred term | Frequency | | | | | | | | | Cardiac disorders
| tachycardia
| Very common
| | General disorders and administration site conditions
| pyrexia
| Very common
| | chills
| Very common
| | Investigations
| blood pressure increased
| Very common
| | oxygen saturation decreased
| Very common
| In a phase 4 study 33 MPS I patients received 1 of 4 dose regimens: 100 U/Kg IV every week (recommended dose), 200 U/Kg IV every week, 200 U/Kg IV every 2 weeks or 300 U/Kg IV every 2 weeks. The recommended dose group had the fewest number of patients who experienced ADRs and IARs. The type of IARs was similar to those seen in other clinical studies.Immunogenicity Almost all patients developed IgG antibodies to laronidase. Most patients seroconverted within 3 months of initiation of treatment; although seroconversion in patients under 5 years old with a more severe phenotype occurred mostly within 1 month (mean 26 days versus 45 days in patients 5 years and older). By the end of the Phase 3 study (or at time of early study withdrawal), 13/45 patients had no detectable antibodies by radioimmunoprecipitation (RIP) assay, including 3 patients that had never seroconverted. Patients with absent to low antibody levels showed a robust reduction in urinary GAG level, whereas patients with high antibody titers showed variable reduction in urinary GAG. The clinical significance of this finding is unknown since there were no consistent relationships between IgG antibody level and clinical efficacy endpoints.In addition 60 patients in the Phase 2 and 3 studies were tested for in-vitro neutralising effects. Four patients (three in the Phase 3 study and one in the Phase 2 study) showed marginal to low level in vitro inhibition of laronidase enzymatic activity, which did not appear to impact clinical efficacy and/or urinary GAG reduction.The presence of antibodies did not appear to be related to the incidence of IARs, although the onset of IARs typically coincided with the formation of IgG antibodies. The occurrence of IgE antibodies was not fully explored. | |