Fabrazyme comes in 5 mg 35 mg powder for concentrate for solution for infusion
Fabrazyme 5 mg powder for concentrate for solution for infusion. Each vial of Fabrazyme contains a nominal value of 35 mg of agalsidase beta. After reconstitution with 7.2 ml water for injections, each vial of Fabrazyme contains 5 mg/ml (35 mg/7 ml) of agalsidase beta. The reconstituted solution must be diluted further Fabrazyme 5 mg powder for concentrate for solution for infusion Each vial of Fabrazyme contains a nominal value of 5 mg of agalsidase beta. After reconstitution with 1.1 ml water for injections, each vial of Fabrazyme contains 5 mg/ml of agalsidase beta. The reconstituted solution must be diluted further.
Agalsidase beta is a recombinant form of human α-galactosidase A and is produced by recombinant DNA technology using a mammalian Chinese Hamster Ovary (CHO) cell culture. The amino acid sequence of the recombinant form, as well as the nucleotide sequence which encoded it, are identical to the natural form of α-galactosidase A.
Fabrazyme is indicated for long-term enzyme replacement therapy in patients with a confirmed diagnosis of Fabry disease (α-galactosidase A deficiency).
Fabrazyme is indicated in adults, children and adolescents aged 8 years and older.
Fabrazyme treatment should be supervised by a physician experienced in the management of patients with Fabry disease or other inherited metabolic diseases.
The recommended dose of Fabrazyme is 1 mg/kg body weight administered once every 2 weeks as an intravenous infusion.
Lower dosing regimens have been used in clinical studies. In one of these studies, performed in adult male patients, after an initial dose of 1.0 mg/kg every 2 weeks for 6 months, 0.3 mg/kg every 2 weeks may maintain clearance of GL-3 in certain cell types in some patients; however, the long term clinical relevance of these findings has not been established.
The initial infusion rate should be no more than 0.25 mg/min (15 mg/hour) to minimise the potential occurrence of infusion-associated reactions. After patient tolerance is established, the infusion rate may be increased gradually with subsequent infusions.
Infusion of Fabrazyme at home may be considered for patients who are tolerating their infusions well. The decision to have a patient move to home infusion should be made after evaluation and recommendation by the treating physician. Patients experiencing adverse events during the home infusion need to immediately stop the infusion process and seek the attention of a healthcare professional. Subsequent infusions may need to occur in a clinical setting. Dose and infusion rate should remain constant while at home, and not be changed without supervision of a healthcare professional.
No dose adjustment is necessary for patients with renal insufficiency.
Studies in patients with hepatic insufficiency have not been performed.
The safety and efficacy of Fabrazyme in patients older than 65 years have not been established and no dosage regimen can presently be recommended in these patients.
The safety and efficacy of Fabrazyme in children aged 0 to7 years have not yet been established. No recommendation on posology can be made in children aged 5 to 7 years. No data are available in children 0 to 4 years
No dose adjustment is necessary for children 8-16 years
Since agalsidase beta (r-hαGAL) is a recombinant protein, the development of IgG antibodies is expected in patients with little or no residual enzyme activity. The majority of patients developed IgG antibodies to r-hαGAL, typically within 3 months of the first infusion with Fabrazyme. Over time, the majority of seropositive patients in clinical trials demonstrated either a downward trend in titers (based on a ≥ 4-fold reduction in titer from the peak measurement to the last measurement) (40% of the patients), tolerised (no detectable antibodies confirmed by 2 consecutive radioimmuno-precipitation (RIP) assays) (14% of the patients) or demonstrated a plateau (35% of the patients).
Patients with antibodies to r-hαGAL have a greater potential to experience infusion-associated reactions (IARs), which are defined as any related adverse event occurring on the infusion day. These patients should be treated with caution when re-administering agalsidase beta. Antibody status should be regularly monitored.
In clinical trials, sixty seven percent (67 %) of the patients experienced at least one infusion-associated reaction. The frequency of IARs decreased over time. Patients experiencing mild or moderate infusion-associated reactions when treated with agalsidase beta during clinical trials have continued therapy after a reduction in the infusion rate (~0.15 mg/min; 10 mg/hr) and/or pre-treatment with antihistamines, paracetamol, ibuprofen and/or corticosteroids.
A small number of patients have experienced reactions suggestive of immediate (Type I) hypersensitivity. If severe allergic or anaphylactic-type reactions occur, immediate discontinuation of the administration of Fabrazyme should be considered and appropriate treatment initiated. The current medical standards for emergency treatment are to be observed.
With careful rechallenge Fabrazyme has been re-administered to all 6 patients who tested positive for IgE antibodies or had a positive skin test to Fabrazyme in a clinical trial. In this trial, the initial rechallenge administration was at a low dose and a lower infusion rate (1/2 the therapeutic dose at 1/25 the initial standard recommended rate). Once a patient tolerates the infusion, the dose may be increased to reach the therapeutic dose of 1 mg/kg and the infusion rate may be increased by slowly titrating upwards, as tolerated.
The effect of Fabrazyme treatment on the kidneys may be limited in patients with advanced renal disease.
Fabrazyme should not be administered with chloroquine, amiodarone, benoquin or gentamycin due to a theoretical risk of inhibition of intra-cellular α-galactosidase A activity.
There are no adequate data from the use of agalsidase beta in pregnant women.
Animal studies do not indicate direct or indirect harmful effects with respect to embryonal/foetal development
Fabrazyme should not be used during pregnancy unless clearly necessary.
Agalsidase beta may be excreted in milk. Because there are no data available on effects in neonates exposed to agalsidase beta via breast milk, it is recommended to stop breast-feeding when Fabrazyme is used.
Summary of the safety profile
Since agalsidase beta (r-hαGAL) is a recombinant protein, the development of IgG antibodies is expected in patients with little or no residual enzyme activity. Patients with antibodies to r-hαGAL have a greater potential to experience infusion-associated reactions (IARs). Reactions suggestive of immediate (Type I) hypersensitivity have been reported in a small number of patients (see section 4.4).
Very common adverse reactions included chills, pyrexia, feeling cold, nausea, vomiting, headache and paraesthesia. Sixty seven percent (67%) of the patients experienced at least one infusion-associated reaction. Anaphylactoid reactions have been reported in the postmarketing setting.
The rationale for enzyme replacement therapy is to restore a level of enzymatic activity sufficient to clear the accumulating substrate in the organ tissues; thereby, preventing, stabilizing or reversing the progressive decline in function of these organs before irreversible damage has occurred.
After intravenous infusion, agalsidase beta is rapidly removed from the circulation and taken up by vascular endothelial and parenchymal cells into lysosomes, likely through the mannose-6 phosphate, mannose and asialoglycoprotein receptors.
Efficacy and safety of Fabrazyme was evaluated in two studies with children, one dose-finding study, two double-blind placebo-controlled studies, and one open-label extension study in both male and female patients.
In the dose finding study, the effects of 0.3, 1.0 and 3.0 mg/kg once every 2 weeks and 1.0 and 3.0 mg/kg once every 2 days were evaluated. A reduction in GL-3 was observed in kidney, heart, skin and plasma at all doses. Plasma GL-3 was cleared in a dose dependent manner, but was less consistent at the dose of 0.3 mg/kg. In addition, infusion-associated reactions were dose dependent.
In the first placebo-controlled clinical trial, Fabrazyme was effective in clearing GL-3 from the vascular endothelium of the kidney after 20 weeks of treatment. This clearance was achieved in 69% (20/29) of the Fabrazyme treated patients, but in none of the placebo patients (p<0.001). This finding was further supported by a statistically significant decrease in GL-3 inclusions in kidney, heart and skin combined and in the individual organs in patients treated with agalsidase beta compared to placebo patients (p<0.001). Sustained clearance of GL-3 from kidney vascular endothelium upon agalsidase beta treatment was demonstrated further in the open label extension of this trial. This was achieved in 47 of the 49 patients (96%) with available information at month 6, and in 8 of the 8 patients (100%) with available information at the end of the study (up to a total of 5 years of treatment). Clearance of GL-3 was also achieved in several other cell types from the kidney. Plasma GL-3 levels rapidly normalised with treatment and remained normal through 5 years.
Renal function, as measured by glomerular filtration rate and serum creatinine, as well as proteinuria, remained stable in the majority of the patients. However, the effect of Fabrazyme treatment on the kidney function was limited in some patients with advanced renal disease.
Although no specific study has been conducted to assess the effect on the neurological signs and symptoms, the results also indicate that patients may achieve reduced pain and enhanced quality of life upon enzyme replacement therapy.
Another double-blind, placebo-controlled study of 82 patients was performed to determine whether Fabrazyme would reduce the rate of occurrence of renal, cardiac, or cerebrovascular disease or death. The rate of clinical events was substantially lower among Fabrazyme-treated patients compared to placebo-treated patients (risk reduction = 53% intent-to-treat population (p=0.0577); risk reduction = 61 % per-protocol population (p=0.0341)). This result was consistent across renal, cardiac and cerebrovascular events.
The results of these studies indicate that Fabrazyme treatment at 1 mg/kg every other week provides clinical benefit on key clinical outcomes in patients with early and advanced Fabry disease. Because this condition is slowly progressive, early detection and treatment is critical to achieve the best outcomes.
In an additional study, 21 male patients were enrolled to follow GL3 clearance in kidney and skin tissues at an alternative dosing regimen. Following treatment with 1 mg/kg every other week for 24 weeks, a dose regimen of 0.3 mg/kg every 2 weeks for 18 months was able to maintain the clearance of cellular GL-3 in the capillary endothelium of the kidney, other kidney cell types and skin (superficial skin capillary endothelium) in the majority of patients. However, at the lower dose, IgG antibodies may play a role with respect to GL-3 clearance in some patients. Due to the limitations of the study design (small number of patients), no definitive conclusion regarding the dose maintenance regimen can be drawn, but these findings suggest that, after an initial debulking dose of 1.0 mg/kg every 2 weeks, 0.3 mg/kg every 2 weeks may be sufficient in some patients to maintain clearance of GL-3.
In the postmarketing setting, experience was gained in patients who initiated treatment at a dose of 1 mg/kg every 2 weeks and subsequently received a reduced dose for an extended period. In some of these patients, an increase of some of the following symptoms was spontaneously reported: pain, paraesthesia and diarrhoea, as well as cardiac, central nervous system and renal manifestations. These reported symptoms resemble the natural course of Fabry disease.
In one open-label paediatric study, sixteen patients with Fabry disease (8-16 years old; 14 males, 2 females) had been treated for one year at 1.0 mg/kg every 2 weeks. Clearance of GL-3 in the superficial skin vascular endothelium was achieved in all patients who had accumulated GL-3 at baseline. The 2 female patients had little or no GL-3 accumulation in the superficial skin vascular endothelium at baseline, making this conclusion applicable in male patients only.
In an additional 5-year open-label paediatric study, 31 male patients aged 5 to 18 years were randomized prior to the onset of clinical symptoms involving major organs and treated with two lower dose regimens of agalsidase beta, 0.5 mg/kg every 2 weeks or 1.0 mg/kg every 4 weeks. Results were similar between the two treatment groups. Superficial skin capillary endothelium GL-3 scores were reduced to zero or maintained at zero at all time points post-baseline upon treatment in 19/27 patients completing the study without a dose increase. Both baseline and 5-year kidney biopsies were obtained in a subset of 6 patients: in all, kidney capillary endothelium GL-3 scores were reduced to zero but highly variable effects were observed in podocyte GL-3, with a reduction in 3 patients. Ten (10) patients met per protocol dose increase criteria, two (2) had a dose increase to the recommended dose of 1.0 mg/kg every 2 weeks.