Treatment of Fabry disease with different dosing regimens of agalsidase: Effects on antibody formation and GL-3
ABSTRACT Two different enzyme preparations are used for the treatment of Fabry disease patients, agalsidase alpha (Replagal, Shire) and agalsidase beta (Fabrazyme, Genzyme). Therapeutic efficacy of both products has been variable probably due to differences in gender, severity, age and other patient characteristics. We studied the occurrence of alpha-Gal A antibodies and their effect on urinary and plasma globotriaosylceramide (GL-3), plasma chitotriosidase and clinical outcome in 52 patients after 12 months of treatment with either 0.2mg/kg agalsidase alppha (10 males, 8 females) or beta (8 males, 5 females) or 1.0mg/kg agalsidase beta (10 males, 11 females). Antibodies were detected in 18/28 male patients after 6 months. None of the females developed antibodies. Following 12 months of 0.2mg/kg treatment, urinary GL-3 decreased in antibody negative (AB-) but increased in antibody positive (AB+) patients. Treatment with 1.0mg/kg gave a reduction in urinary GL-3 in both AB- and AB+ patients. Levels of plasma GL-3 and chitotriosidase decreased in all patient groups. Twelve months of 0.2mg/kg treatment did not change renal function or left ventricular mass. Further, no change in renal function was seen following 1.0mg/kg treatment and left ventricular mass decreased in both AB- and AB+ patients. In summary, alpha-Gal A antibodies frequently develop in male Fabry disease patients and interfere with urinary GL-3 excretion. Infusion of a dose of 1.0mg/kg results in a more robust decline in GL-3, less impact, if any of antibodies, stable renal function and reduction of LVMass.
Article: Agalsidase Alfa[Show abstract] [Hide abstract]
ABSTRACT: The enzyme replacement therapy agalsidase alfa (Replagal®) has an amino acid sequence identical to that of native α-galactosidase A; intravenous agalsidase alfa 0.2 mg/kg every other week is indicated for the long-term treatment of patients with confirmed Fabry disease. This article reviews the efficacy and tolerability of agalsidase alfa in patients with Fabry disease, as well as summarizing its pharmacologic properties. Agalsidase alfa had beneficial effects in adult men with Fabry disease, according to the results of two randomized, double-blind, placebo-controlled, 6-month trials (n= 15 and 26). For example, left ventricular mass index was reduced to a significantly greater extent with agalsidase alfa than with placebo. Although the change in myocardial globotriaosylceramide content (primary endpoint in one study) did not significantly differ between agalsidase alfa and placebo recipients, the change in the Brief Pain Inventory (BPI) ‘pain at its worst’ score (reflecting neuropathic pain while without pain medications; primary endpoint in the second study) was improved to a significantly greater extent with agalsidase alfa than with placebo. In addition, the change in creatinine clearance, but not inulin clearance, significantly favored agalsidase alfa versus placebo recipients. Abnormalities in functional cerebral blood flow and cerebrovascular responses were also reversed with agalsidase alfa therapy. In extensions of these placebo-controlled trials, the reduction in left ventricular mass and improvements in BPI pain scores were maintained after longer-term agalsidase alfa therapy. The significant decline in estimated glomerular filtration rate (eGFR) seen after 48 months’ agalsidase alfa treatment was mainly driven by a marked decline in eGFR seen in four patients with stage 3 chronic kidney disease at baseline (although the progression of decline appeared slower than that seen in historic controls); renal function appeared stable in patients with stage 1 or 2 chronic kidney disease. Certain benefits of agalsidase alfa became apparent with longer-term therapy. For example, a significant reduction in cold and warm detection thresholds and a significant improvement in sweat function were seen after 3 years’ therapy. Final results from a head-to-head trial comparing the effects of agalsidase alfa and agalsidase beta at approved dosages are not yet available. The only available fully published study compared agalsidase alfa 0.2 mg/kg every other week with an off-label dosage of agalsidase beta 0.2 mg/kg every other week. This randomized, open-label, 24-month trial in adult men and women with Fabry disease generally found no significant differences in outcome between treatment arms. It should be noted that concerns were subsequently raised by the European Medicines Agency regarding the use of agalsidase beta at dosages other than the approved dosage of 1 mg/kg every other week. Preliminary results from an ongoing, randomized, open-label study suggest no differences in outcome between patients with Fabry disease receiving intravenous agalsidase alfa 0.2 mg/kg every other week and those receiving the approved regimen of agalsidase beta 1 mg/kg every other week. In three switching studies, no safety concerns were raised and disease stability was generally maintained following the switch from agalsidase beta 1 mg/kg every other week to agalsidase alfa 0.2 mg/kg every other week. Agalsidase alfa also demonstrated beneficial effects, including in women and pediatric patients, in non-comparative studies and in the Fabry Outcome Survey. Agalsidase alfa was generally well tolerated in patients with Fabry disease, with infusion reactions (e.g. rigors, pyrexia, flushing) being the most commonly occurring adverse event. IgG antibodies developed in ≈24% of male patients with Fabry disease who received agalsidase alfa. After 12–54 months of treatment, 17% of agalsidase alfa recipients were still IgG antibody positive, with immunologic tolerance developing in 7% of agalsidase alfa recipients. No IgE antibodies have been detected in any patient receiving agalsidase alfa. No antibody formation was reported in women receiving agalsidase alfa in noncomparative studies. In conclusion, agalsidase alfa is an effective and well tolerated treatment option for use in patients with Fabry disease.BioDrugs 10/2012; 26(5). DOI:10.1007/BF03261891 · 2.12 Impact Factor
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ABSTRACT: Fabry disease is an X-linked genetic disorder caused by defects in the α-galactosidase A (GLA) gene, and heterogeneous mutations lead to quantitative and/or qualitative defects in GLA protein in male patients with Fabry disease. Random X-chromosomal inactivation modifies the clinical and biochemical features of female patients with Fabry disease. Functional polymorphisms have been frequently reported in recent times, and these increase the difficulty of understanding the pathogenetic basis of the disease. To date, GLA protein level has been measured using an enzyme-linked immunosorbent assay (ELISA). However, ELISA is not highly sensitive due to the high background noise. In this paper, we introduce a novel application of the immuno-polymerase chain reaction (PCR) method (termed Multiple Simultaneous Tag [MUSTag]) for measurement of the GLA protein level in blood samples. We compared the sensitivities of the MUSTag method with plates or magnetic beads with those of ELISA for recombinant human GLA and found that the apparent maximal sensitivity was higher for the former than for the latter. We then measured the GLA concentrations in serum and plasma from male patients with classic Fabry disease (Male Fabry), females with Fabry disease (Female Fabry), male subjects harboring the functional polymorphism p.E66Q (E66Q), and control (Control) subjects. Our results revealed that compared to the MUSTag plate and ELISA, the MUSTag beads assay afforded a clearer estimation of the GLA protein levels in the serum and plasma with minimal or no background noise, although all the methods could differentiate between the Male Fabry, E66Q, and Control groups. The Female Fabry group showed characteristic heterogeneity, which was consistent with the X-linked inheritance. This novel method is expected to be useful for the sensitive determination of GLA level in blood and elucidation of the pathogenetic basis of Fabry disease.PLoS ONE 11/2013; 8(11):e78588. DOI:10.1371/journal.pone.0078588 · 3.53 Impact Factor
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ABSTRACT: Fabry disease is an X-linked inborn error of glycolipid metabolism caused by deficiency of the human lysosomal enzyme, α-galactosidase A (αGal), leading to strokes, myocardial infarctions, and terminal renal failure, often leading to death in the fourth or fifth decade of life. The enzyme is responsible for the hydrolysis of terminal α-galactoside linkages in various glycolipids. Enzyme replacement therapy (ERT) has been approved for the treatment of Fabry disease, but adverse reactions, including immune reactions, make it desirable to generate improved methods for ERT. One approach to circumvent these adverse reactions is the development of derivatives of the enzyme with more activity per mg. It was previously reported that carboxyl-terminal deletions of 2 to 10 amino acids led to increased activity of about 2 to 6-fold. However, this data was qualitative or semi-quantitative and relied on comparison of the amounts of mRNA present in Northern blots with αGal enzyme activity using a transient expression system in COS-1 cells. Here we follow up on this report by constructing and purifying mutant enzymes with deletions of 2, 4, 6, 8, and 10 C-terminal amino acids (Δ2, Δ4, Δ6, Δ8, Δ10) for unambiguous quantitative enzyme assays. The results reported here show that the kcat/Km approximately doubles with deletions of 2, 4, 6 and 10 amino acids (0.8 to 1.7-fold effect) while a deletion of 8 amino acids decreases the kcat/Km (7.2-fold effect). These results indicate that the mutated enzymes with increased activity constructed here would be expected to have a greater therapeutic effect on a per mg basis, and could therefore reduce the likelihood of adverse infusion related reactions in Fabry patients receiving ERT treatment. These results also illustrate the principle that in vitro mutagenesis can be used to generate αGal derivatives with improved enzyme activity.PLoS ONE 01/2015; 10(2):e0118341. DOI:10.1371/journal.pone.0118341 · 3.53 Impact Factor