1. Name Of The Medicinal Product
Carbaglu 200 mg dispersible tablets
2. Qualitative And Quantitative Composition
Each tablet contains 200 mg of carglumic acid.
For a full list of excipients, see section 6.1
3. Pharmaceutical Form
Dispersible tablet
The tablets are white and elongated with three score marks.
The tablet can be divided into equal halves.
4. Clinical Particulars
4.1 Therapeutic Indications
Treatment of hyperammonaemia due to N-acetylglutamate synthase deficiency.
4.2 Posology And Method Of Administration
Carbaglu treatment should be initiated under the supervision of a physician experienced in the treatment of metabolic disorders.
Based on clinical experience, the treatment may be started as early as the first day of life.
The initial daily dose should be 100 mg/kg, up to 250 mg/kg if necessary.
It should then be adjusted individually in order to maintain normal ammonia plasma levels (see section 4.4).
In the long term, it may not be necessary to increase the dose according to body weight as long as adequate metabolic control is achieved; daily doses range from 10 mg/kg to 100 mg/kg.
Carglumic acid responsiveness test
It is recommended to test individual responsiveness to carglumic acid before initiating any long term treatment. As examples
- In a comatose child, start with a dose of 100 to 250 mg/kg/day and measure ammonia plasma concentration at least before each administration; it should normalise within a few hours after starting Carbaglu.
- In a patient with moderate hyperammonaemia, administer a test dose of 100 to 200 mg/kg/day for 3 days with a constant protein intake and perform repeated determinations of ammonia plasma concentration (before and 1 hour after a meal); adjust the dose in order to maintain normal ammonia plasma levels.
Based on pharmacokinetic data and clinical experience, it is recommended to divide the total daily dose into two to four doses to be given before meals or feedings. The breaking of the tablets in halves allows most of the required posology adjustments. Occasionally, the use of quarter tablets may also be useful to adjust the posology prescribed by the physician.
The tablets must be dispersed in a minimum of 5-10 ml of water and ingested immediately or administered by fast push through a syringe via a nasogastric tube.
The suspension has a slightly acidic taste.
4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients.
Breast-feeding during the use of carglumic acid is contraindicated (see sections 4.6 and 5.3).
4.4 Special Warnings And Precautions For Use
Therapeutic monitoring
Plasma levels of ammonia and amino acids should be maintained within normal limits.
As very few data on the safety of carglumic acid are available, systematic surveillance of liver, renal, cardiac functions and haematological parameters is recommended.
Nutritional management
Protein restriction and arginine supplementation may be indicated in case of low protein tolerance.
4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction
No specific interaction studies have been performed.
4.6 Pregnancy And Lactation
For carglumic acid no clinical data on exposed pregnancies are available.
Animal studies have revealed minimal developmental toxicity (see section 5.3). Caution should be exercised when prescribing to pregnant women.
Although it is not known whether carglumic acid is secreted into human milk, it has been shown to be present in the milk of lactating rats (see section 5.3). Therefore, breast-feeding during the use of carglumic acid is contraindicated. (see section 4.3).
4.7 Effects On Ability To Drive And Use Machines
No studies on the effects on the ability to drive and use machines have been performed.
4.8 Undesirable Effects
Clinical experience has been collected in about 170 patient-years.
Reported adverse reactions are listed below, by system organ class and by frequency. Frequencies are defined as: very common (
Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness
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4.9 Overdose
In one patient treated with carglumic acid, where the dose was increased up to 750 mg/kg/day, symptoms of intoxication occurred which can be characterised as a sympathomimetic reaction: tachycardia, profuse sweating, increased bronchial secretion, increased body temperature and restlessness. These symptoms resolved once the dose was reduced.
5. Pharmacological Properties
5.1 Pharmacodynamic Properties
Pharmacotherapeutic group: Amino acids and derivatives; ATC code: A16AA05
Carglumic acid is a structural analogue of N-acetylglutamate, which is the naturally occurring activator of carbamoyl phosphate synthetase, the first enzyme of the urea cycle.
Carglumic acid has been shown in vitro to activate liver carbamoyl phosphate synthetase. Despite a lower affinity of carbamoyl phosphate synthetase for carglumic acid than for N-acetylglutamate, carglumic acid has been shown in vivo to stimulate carbamoyl phosphate synthetase and to be much more effective than N-acetylglutamate in protecting against ammonia intoxication in rats. This could be explained by the following observations:
i) The mitochondrial membrane is more readily permeable for carglumic acid than for N-acetylglutamate
ii) Carglumic acid is more resistant than N-acetylglutamate to hydrolysis by aminoacylase present in the cytosol.
Other studies have been conducted in rats under different experimental conditions leading to increased ammonia availability (starvation, protein-free or high-protein diet). Carglumic acid was shown to decrease blood ammonia levels and increase urea levels in blood and urine, whereas the liver content of carbamoyl phosphate synthetase activators was significantly increased.
In patients with N-acetylglutamate synthase deficiency, carglumic acid was shown to induce a rapid normalisation of plasma ammonia levels, usually within 24 hours. When the treatment was instituted before any permanent brain damage, patients exhibited normal growth and psychomotor development.
5.2 Pharmacokinetic Properties
The pharmacokinetics of carglumic acid has been studied in healthy male volunteers using both radiolabelled and unlabelled product.
Absorption
After a single oral dose of 100 mg/kg body weight, approximately 30% of carglumic acid is estimated to be absorbed. At that dose-level, in 12 volunteers given Carbaglu tablets, plasma concentration peaked at 2.6 μg/ml (median; range 1.8-4.8) after 3 hours (median; range 2-4).
Distribution
The plasma elimination curve of carglumic acid is biphasic with a rapid phase over the first 12 hours after administration followed by a slow phase (terminal half life up to 28 hours).
Diffusion into erythrocytes is non existent. Protein binding has not been determined.
Metabolism
A proportion of carglumic acid is metabolised. It is suggested that depending on its activity, the intestinal bacterial flora may contribute to the initiation of the degradation process, thus leading to a variable extent of metabolism of the molecule. One metabolite that has been identified in the faeces is glutamic acid. Metabolites are detectable in plasma with a peak at 36-48 hours and a very slow decline (half-life around 100 hours).
The end product of carglumic acid metabolism is carbon dioxide, which is eliminated through the lungs.
Elimination
After a single oral dose of 100 mg/kg body weight, 9% of the dose is excreted unchanged in the urine and up to 60% in the faeces.
Plasma levels of carglumic acid were measured in patients of all age categories, from newborn infants to adolescents, treated with various daily doses (7 – 122 mg/kg/day). Their range was consistent with those measured in healthy adults, even in newborn infants. Whatever the daily dose, they were slowly declining over 15 hours to levels around 100 ng/ml.
5.3 Preclinical Safety Data
Safety pharmacology studies have shown that Carbaglu administered orally at doses of 250, 500, 1000 mg/kg had no statistically significant effect on respiration, central nervous system and cardiovascular system.
Carbaglu showed no significant mutagenic activity in a battery of genotoxicity tests performed in vitro (Ames test, human lymphocyte metaphase analysis) and in vivo (micronucleus test in rat).
Single doses of carglumic acid up to 2800 mg/kg orally and 239 mg/kg intravenously did not induce any mortality or abnormal clinical signs in adult rats. In newborn rats receiving daily carglumic acid by oral gavage for 18 days as well as in young rats receiving daily carglumic acid for 26 weeks, the No Observed Effect Level (NOEL) was established at 500 mg/kg/day and the No Observed Adverse Effect Level (NOAEL) was established at 1000 mg/kg/day.
No adverse effects have been observed on male or female fertility. In rats and rabbits no evidence has been seen of embryotoxicity, foetotoxicity or teratogenicity up to maternotoxic doses leading to fifty times exposure as compared to humans in rats and seven times in rabbits. Carglumic acid is secreted in the milk of lactating rats and although developmental parameters were unaffected, there were some effects on body weight / body weight gain of pups breast-fed by dams treated with 500 mg/kg/day and a higher mortality of pups from dams treated with 2000/kg/day, a dose that caused maternotoxicity. The maternal systemic exposures after 500 and 2000 mg/kg/day were twenty five times and seventy times the expected human exposure.
No carcinogenicity study has been conducted with carglumic acid.
6. Pharmaceutical Particulars
6.1 List Of Excipients
Microcrystalline cellulose
sodium laurilsulfate
hypromellose
croscarmellose sodium
silica colloidal anhydrous
sodium stearyl fumarate
6.2 Incompatibilities
Not applicable
6.3 Shelf Life
30 months
After first opening of the tablet container: 1 month
6.4 Special Precautions For Storage
Store in a refrigerator (2°C – 8°C)
After first opening of the tablet container:
Do not refrigerate.
Do not store above 30°C.
Keep the container tightly closed in order to protect from moisture.
6.5 Nature And Contents Of Container
5- or 60- polypropylene tablet containers closed by a polyethylene cap with a desiccant unit.
6.6 Special Precautions For Disposal And Other Handling
No special requirements
7. Marketing Authorisation Holder
Orphan Europe
Immeuble “Le Wilson”
F-92058 Paris La Défense
France
8. Marketing Authorisation Number(S)
EU/1/02/246/002 (60 dispersible tablets)
EU/1/02/246/003 (5 dispersible tablets)
9. Date Of First Authorisation/Renewal Of The Authorisation
24 January 2003
24 January 2008
10. Date Of Revision Of The Text
Detailed information on this medicinal product is available on the website of the European Medicines Agency (EMEA) http://www.emea.europa.eu/.
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