Clinical trials are a scientific way to measure and compare the effectiveness and safety of a treatment with something else, to determine if a treatment can help patients. The data can be analyzed by statistical tests to check that the observation is not random chance.
Clinical trials in patients 5 years and older
The safety and efficacy of ELAPRASE were evaluated in a 12-month clinical study of 96 patients with Hunter syndrome aged 5 years and older. The trial was a double-blind, placebo-controlled study, meaning that it compared the effects of using ELAPRASE in some patients with using no ELAPRASE in other patients, without the doctors knowing which patient was treated with what (so that the measurements could not be biased by this information).
This study looked at the possibility of two different ELAPRASE dosing schedules, comparing them to placebo.These data were used to support the approved dosing of the 0.5 mg per kg of body weight once per week infusion schedule.
Hypersensitivity reactions were reported in 69% (22 of 32) of patients in the ELAPRASE once-weekly group.
Adverse reactions that occurred in at least three patients (≥9%) in the ELAPRASE once-weekly group and had a higher incidence than in the placebo group included:1
|System organ class
(0.5 mg/kg weekly)
|Diarrhea||3 (9%)||1 (3%)|
connective tissue disorders
|Musculoskeletal pain||4 (13%)||1 (3%)|
|Nervous system disorders|
|Headache||9 (28%)||8 (25%)|
|Respiratory, thoracic and
|Cough||3 (9%)||1 (3%)|
|Skin and subcutaneous
|Pruritus||8 (25%)||3 (9%)|
|Urticaria||5 (16%)||0 (0%)|
Additional adverse reactions that occurred in at least 9% of patients (≥3 patients) in the ELAPRASE 0.5 mg/kg once every other week group and occurred more frequently than the placebo group included rash (19%), flushing (16%), fatigue (13%), rapid heart rate (9%), and chills (9%).
Read more about Elaprase Important Safety Information here.
The primary endpoint of the trial was a two-component
score based on the analysis of:
The distance walked
during a 6-minute
walking test (6-MWT)
An assessment of lung
function called % predicted
forced vital capacity (% FVC)
Patients in the ELAPRASE weekly treatment group exhibited a significant improvement in the primary efficacy endpoint, as compared to patients who received placebo
When the individual components were examined separately, patients receiving ELAPRASE treatment for 12 months could walk an average 35 meters more in 6 minutes than patients receiving placebo – this difference was statistically significant. The difference in % predicted FVC was not statistically significant.
The clinical trial also measured levels of GAGs in patient’s urine and the size of their liver and spleen to assess whether GAG storage levels inside the body were improved by ELAPRASE. Results showed that the placebo did not reduce liver and spleen size, whereas ELAPRASE once weekly reduced liver and spleen size. Additionally, the placebo did not alter urine GAG levels; ELAPASE once weekly reduced urine GAG levels, although in half of the patients, the urine GAG levels were still considered higher than normal.
Clinical trial in patients 7 years and younger
A clinical trial evaluating the safety of ELAPRASE in 28 patients aged 16 months to 7 years was carried out, but did not measure walking ability as it was impractical to do so due to age group based on disease state. However, treatment with ELAPRASE was shown to reduce spleen size in patients aged 16 months to 5 years, which was similar to the spleen size reduction shown with ELAPRASE in the clinical trial of patients 5 years and older.
The safety results of this study showed that patients with certain types of genetic mutations experienced a higher number of allergic reactions, serious side effects, and development of an immune response to treatment. This immune response may interfere with the effectiveness of ELAPRASE. Talk to your healthcare team about whether you or your child may be at risk.
Patients experienced similar adverse reactions as those observed in clinical trials in patients 5 years and older, with the most common adverse reactions following ELAPRASE treatment being allergic (hypersensitivity) reactions (57%). A higher incidence of the following common hypersensitivity reactions were reported in this younger age group: fever (36%), rash (32%), and vomiting (14%). The most common serious adverse reactions occurring in at least 10% of patients (≥3 patients) included: bronchopneumonia/pneumonia (18%), ear infection (11%), and fever (11%).
RISK OF SERIOUS ALLERGIC REACTIONS
Some patients have experienced serious allergic reactions (including life-threatening anaphylactic reactions) during and up to 24 hours after treatment, regardless of how long they were taking ELAPRASE. Anaphylactic reactions are immediate and include breathing problems, low oxygen levels, low blood pressure, hives and/or swelling of the throat or tongue. If a patient (you or your child) has experienced an anaphylactic reaction, the patient may require an extended period of observation by the patient’s healthcare team. If you or your child has breathing problems, a fever, or a respiratory illness, you or your child may be at risk of life-threatening worsening of those conditions due to allergic reactions from ELAPRASE. Your healthcare team should be advised of those conditions before treatment with ELAPRASE because the information may affect the timing of ELAPRASE treatment.
You or your child should be closely watched during and after ELAPRASE treatment and you should confirm with your healthcare team in advance of treatment that it is prepared to manage serious allergic reactions, including anaphylactic reactions. Tell your healthcare team immediately if any signs of an allergic reaction happen. Those signs may include breathing problems, low blood pressure, rash, hives, itching, flushing, fever and/or headache.
When serious allergic reactions happened during clinical trials, later ELAPRASE treatments were managed with allergy-controlling drugs before or during treatment, a slower rate of ELAPRASE treatment, and/or early discontinuation of treatment.
Children with serious genetic mutations may be at risk for allergic reactions, serious side effects and antibody development. In a clinical study of children 7 years and younger, patients with certain types of genetic mutations experienced a higher number of allergic reactions, serious side effects, and development of an immune response to treatment. This immune response may interfere with the effectiveness of ELAPRASE. Talk to your healthcare team about whether you or your child may be at risk.
If you or your child has breathing problems, other respiratory illness, heart problems, or susceptibility to fluid overload, you or your child may be at higher risk of fluid overload during ELAPRASE treatment. Your healthcare team should be advised of those problems before treatment and you should confirm with your healthcare team in advance of treatment that it is appropriately trained to watch for signs of fluid overload and provide the necessary medical support. Patients at risk for fluid overload may require longer observation time.
What are possible side effects of ELAPRASE?
The most common side effects of ELAPRASE include:
The most common side effects needing medical attention were allergic reactions, and included rash, hives, itching, flushing, fever, and headache. Tell your healthcare team immediately if any signs of an allergic reaction happen. These are not all the possible side effects of ELAPRASE.
What is ELAPRASE (idursulfase)?
ELAPRASE is a prescription medicine for patients with Hunter syndrome. ELAPRASE has been shown to improve walking ability in patients 5 yrs and older. In patients 16 months to 5 years old, ELAPRASE did not show improvement in disease-related symptoms or long-term clinical results; however, treatment with ELAPRASE has reduced spleen size similarly to patients 5 yrs and older. It is not known if ELAPRASE is safe and effective in children under 16 months old.