Clinical outcomes in elderly patients receiving agalsidase alfa treatment in the Fabry Outcome Survey.

BACKGROUND AND OBJECTIVES: Treatment with agalsidase alfa in patients with Fabry disease is most effective when initiated early in the disease course; however, the clinical benefits in elderly patients are less well established. This analysis assesses outcomes in patients aged 65 years or older from the Fabry Outcome Survey (FOS) who were treated with agalsidase alfa. METHODS: FOS data were extracted for adult patients aged 65 years or older who received agalsidase alfa, had baseline data and at least 3 years of post-baseline data, and had undergone no renal transplantation and/or dialysis before treatment. The data of patients who had undergone renal transplantation and/or dialysis during follow-up were excluded from estimated glomerular filtration rate (eGFR) analysis after the date of the renal transplantation and/or dialysis. Adult patients were stratified into two groups: those who started treatment before 65 years of age and who were still being treated when aged 65 years or older (group A), and those who started treatment when aged 65 years or older (group B). Mean annual changes in left ventricular mass index (LVMI), eGFR and proteinuria were assessed in group A (before and after the age of 65 years to understand if there was an age-related effect once patients turned 65 years of age) and in group B. RESULTS: Estimated mean (standard error [SE]) annual changes in LVMI were 0.46 (0.26) g/m2.7 and 0.21 (0.42) g/m2.7 in patients in group A when they were younger than 65 years and when they were aged 65 years or older, respectively, and 0.12 (0.65) g/m2.7 in patients in group B. For eGFR, mean (SE) annual changes were 0.83 (2.12) mL/min/1.73 m2 and 2.64 (2.18) mL/min/1.73 m2 in patients in group A when they were younger than 65 years and when they were aged 65 years or older, respectively, and 2.31 (1.44) mL/min/1.73 m2 in patients in group B. Proteinuria remained relatively stable in both subgroups of group A (before and after the age of 65 years) and group B. CONCLUSIONS: Continuation and initiation of agalsidase alfa treatment in patients aged 65 years or older with Fabry disease were associated with stabilization of proteinuria and minimal increases in cardiac (LVMI) and renal (eGFR) outcomes.

Treatment switch in Fabry disease- a matter of dose?

BACKGROUND: Patients with Fabry disease (FD) on reduced dose of agalsidase-beta or after switch to agalsidase-alfa show a decline in chronic kidney disease epidemiology collaboration-based estimated glomerular filtration rate (eGFR) and a worsened plasma lyso-Gb3 decrease. Hence, the most effective dose is still a matter of debate. METHODS: In this prospective observational study, we assessed end-organ damage and clinical symptoms in 78 patients who had received agalsidase-beta (1.0 mg/kg) for >1 year, which were assigned to continue this treatment (agalsidase-beta, regular-dose group, n=17); received a reduced dose of agalsidase-beta and subsequent switch to agalsidase-alfa (0.2 mg/kg) or a direct switch to 0.2 mg/kg agalsidase-alfa (switch group, n=22); or were re-switched to agalsidase-beta after receiving agalsidase-alfa for 12 months (re-switch group, n=39) with a follow-up of 88±25 months. RESULTS: No differences for clinical events were observed for all groups. Patients within the re-switch group started with the worst eGFR values at baseline (p=0.0217). Overall, eGFR values remained stable in the regular-dose group (p=0.1052) and decreased significantly in the re-switch and switch groups (p<0.0001 and p=0.0052, respectively). However, in all groups males presented with an annual loss of eGFR by -2.9, -2.5 and -3.9 mL/min/1.73 m² (regular-dose, re-switch, switch groups, all p<0.05). In females, eGFR decreased significantly only in the re-switch group by -2.9 mL/min/1.73 m² per year (p<0.01). Lyso-Gb3 decreased in the re-switch group after a change back to agalsidase-beta (p<0.05). CONCLUSIONS: Our data suggest that a re-switch to high dosage of agalsidase results in a better biochemical response, but not in a significant renal amelioration especially in classical males.

Fabry disease during the COVID-19 pandemic. Why and how treatment should be continued.

Fabry disease is an X-linked disease due to a deficiency of the lysosomal enzyme alpha-galactosidase A. Clinical symptoms in classically affected males include acroparesthesia, anhydrosis and angiokeratoma, which may present during childhood followed by cardiac, cerebral and renal complications. Even though pulmonary involvement is not widely appreciated by clinicians, an obstructive lung disease is another recognized component of Fabry disease. Coronavirus Disease-19 (COVID-19), caused by the SARS-CoV-2 virus was labeled as a global pandemic and patients with Fabry disease can be considered at high risk of developing severe complications. The impact of COVID-19 on patients with Fabry disease receiving enzyme replacement therapy is still unknown. Many patients who receive treatment in the hospital experienced infusion disruptions due to fear of infection. Effects of temporary treatment interruption was described in more detail in other lysosomal storage diseases, but the recommencement of therapy does not fully reverse clinical decline due to the temporary discontinuation. When possible, home-therapy seems to be the most efficient way to maintain enzyme replacement therapy access during pandemic. Sentence take-home message: Home-therapy, when possible, seems to be the most efficient way to maintain enzyme replacement therapy access during pandemic in patients with Fabry disease.

The Interaction of Innate and Adaptive Immunity and Stabilization of Mast Cell Activation in Management of Infusion Related Reactions in Patients with Fabry Disease.

Fabry disease (FD) is an X-linked lysosomal disorder caused by mutations in GLA gene resulting in lack of or faulty α-galactosidase A (α-GalA) enzyme. Enzyme replacement therapy (ERT) with recombinant human α-GalA enzyme (agalsidase) is the standard treatment option for FD. Infusion-related reactions (IRRs), with symptoms ranging from rigors, to fever, pain, vomiting, angioedema and diarrhea, are often seen due to immune response against the exogenous enzyme. To elucidate the mechanisms causing the IRRs in FD, eight patients who developed IRRs were investigated. All, except one, tested negative for agalsidase-specific IgE and had normal tryptase levels. Circulating dendritic cells were drastically reduced during IRRs, suggesting possible sequestration to the sites of inflammation. An increase in NK cells and a decrease in T cells were also observed. Cytokines IL-4, IL-8 and TNF-α showed a significant increase, indicating nonspecific degranulation of mast cells. All IRRs were managed successfully using a combination of standard premedications and mast cell stabilizers without any interruption of therapy. Taken together, the results indicate crosstalk between immune cells resulting in IgE-independent mast-cell-specific allergic inflammation. Mast cell stabilizers could be used to control IRRs and for safe reintroduction of agalsidase in patients previously treated with ERT.

Agalsidase alfa versus agalsidase beta for the treatment of Fabry disease: an international cohort study.

BACKGROUND: Two recombinant enzymes (agalsidase alfa 0.2 mg/kg/every other week and agalsidase beta 1.0 mg/kg/every other week) have been registered for the treatment of Fabry disease (FD), at equal high costs. An independent international initiative compared clinical and biochemical outcomes of the two enzymes. METHODS: In this multicentre retrospective cohort study, clinical event rate, left ventricular mass index (LVMI), estimated glomerular filtration rate (eGFR), antibody formation and globotriaosylsphingosine (lysoGb3) levels were compared between patients with FD treated with agalsidase alfa and beta at their registered dose after correction for phenotype and sex. RESULTS: 387 patients (192 women) were included, 248 patients received agalsidase alfa. Mean age at start of enzyme replacement therapy was 46 (±15) years. Propensity score matched analysis revealed a similar event rate for both enzymes (HR 0.96, P=0.87). The decrease in plasma lysoGb3 was more robust following treatment with agalsidase beta, specifically in men with classical FD (ß: -18 nmol/L, P<0.001), persisting in the presence of antibodies. The risk to develop antibodies was higher for patients treated with agalsidase beta (OR 2.8, P=0.04). LVMI decreased in a higher proportion following the first year of agalsidase beta treatment (OR 2.27, P=0.03), while eGFR slopes were similar. CONCLUSIONS: Treatment with agalsidase beta at higher dose compared with agalsidase alfa does not result in a difference in clinical events, which occurred especially in those with more advanced disease. A greater biochemical response, also in the presence of antibodies, and better reduction in left ventricular mass was observed with agalsidase beta.

Dose-Dependent Effect of Enzyme Replacement Therapy on Neutralizing Antidrug Antibody Titers and Clinical Outcome in Patients with Fabry Disease.

BACKGROUND: Use of enzyme replacement therapy (ERT) to treat Fabry disease, caused by deficient lysosomal α-galactosidase A activity, can lead to formation of neutralizing antidrug antibodies (ADAs). These antibodies are associated with increased accumulation of plasma globotriaosylceramide (Gb3) and disease progression. Because agalsidase ERT can saturate ADA-binding sites during infusions (achieving agalsidase/antibody equilibrium), we investigated in this open cohort study whether saturated patients (who have excess agalsidase after infusions) experience better clinical outcomes compared with not saturated patients (who have excess ADAs after infusions). METHODS: We isolated ADAs from sera of 26 men with Fabry disease receiving ERT (for a median of 94 months) and determined the amount of agalsidase necessary for antibody saturation. Clinical and biochemical outcomes included measurements of eGFR, interventricular septum thickness, and lyso-Gb3. RESULTS: ADA titers decreased significantly in all patients during infusion. Agalsidase-α and agalsidase-ß had similar ADA-binding capacity and comparable ADA saturation frequency. Fourteen patients with saturated ADAs presented with mild (but significant) loss of eGFR, stable septum thickness, and significantly decreased lyso-Gb3 levels. The 12 not saturated patients had a more pronounced and significant loss of eGFR, increased septum thickness, and a smaller, nonsignificant reduction in lyso-Gb3, over time. In three patients, dose escalation resulted in partially elevated ADA titers, but importantly, also in reduced lyso-Gb3 levels. CONCLUSIONS: A not saturated ADA status during infusion is associated with progressive loss of eGFR and ongoing cardiac hypertrophy. Dose escalation can result in saturation of ADAs and decreasing lyso-Gb3 levels, but may lead to increased ADA titers.

Long-Term Effects of Enzyme Replacement Therapy for Anderson-Fabry Disease.

Anderson-Fabry disease is a rare X-linked lysosomal storage disease caused by α-galactosidase A (α-GalA) gene variants and characterized by a large genotypic and phenotypic spectrum. Enzyme replacement therapy (ERT) using recombinant α-GalA has been approved for > 10 years as a specific therapy for the disease. However, the long-term clinical efficacy for cardiac manifestations has been equivocal because it depends on several factors such as genotype, sex, age, and disease severity at the initiation of ERT. We report the differences in the clinical effects of ERT continued for > 10 years in three patients with the same genotype. Left ventricular hypertrophy and myocardial dysfunction progressed in the heterozygote proband even under ERT, although disease progression was prevented in two sons of Case 1.

The utility of the FIPI score in predicting long-term clinical outcomes in patients with Fabry disease receiving enzyme replacement therapy with agalsidase alfa.

Fabry disease is a rare X-linked lysosomal storage disorder in which there is deficiency of alpha galactosidase A. Enzyme replacement therapy (ERT) is commercially available and has been demonstrated to improve cardiac and renal outcomes. Predictive scores, such as the Fabry International Prognostic Index (FIPI), have been developed to stratify disease severity; however, these have not been validated to predict outcomes in patients receiving ERT. We show that the FIPI score at baseline can predict outcomes in a group of patients on long-term ERT.

Non-clinical evaluation of JR-051 as a biosimilar to agalsidase beta for the treatment of Fabry disease.

Fabry disease (FD) is an X-linked lysosomal storage disease. It is caused by deficiency of the enzyme α-galactosidase A (α-Gal A), which leads to excessive deposition of neutral glycosphingolipids, especially globotriaosylceramide (GL-3), in cells throughout the body. Progressive accumulation of GL-3 causes life-threatening complications in several tissues and organs, including the vasculature, heart, and kidney. Currently available enzyme replacement therapy for FD employs recombinant α-Gal A in two formulations, namely agalsidase alfa and agalsidase beta. Here, we evaluated JR-051 as a biosimilar to agalsidase beta in a non-clinical study. JR-051 was shown to have identical primary and similar higher-order structures to agalsidase beta. Mannose-6-phosphate content was higher in JR-051 than in agalsidase beta, which probably accounts for a slightly better uptake into fibroblasts in vitro. In spite of these differences in in vitro biological features, pharmacokinetic profiles of the two compounds in mice, rats, and monkeys were similar. The ability to reduce GL-3 accumulation in the kidney, heart, skin, liver, spleen, and plasma of Gla-knockout mice, a model of FD, was not different between JR-051 and agalsidase beta. Furthermore, we identified no safety concerns regarding JR-051 in a 13-week evaluation using cynomolgus monkeys. These findings indicate that JR-051 is similar to agalsidase beta in terms of physicochemical and biological properties.

The isozyme selective phosphodiesterase-4 inhibitor, ABI-4, attenuates the effects of lipopolysaccharide in human cells and rodent models of peripheral and CNS inflammation.

Inhibitors of phosphodiesterase-4 (PDE4) have been approved for the treatment of inflammatory disorders, but are associated with dose-limiting nausea and vomiting. These side effects are hypothesized to be mediated by inhibition of the PDE4D isozyme. Here we demonstrate the anti-inflammatory effects of the novel brain penetrant PDE4D-sparing PDE4 inhibitor, ABI-4. ABI-4 was a potent (EC50∼14nM) inhibitor of lipopolysaccharide (LPS) induced TNF-α release from mouse microglia and human PBMCs. ABI-4 (0.32mg/kg) blocked LPS-induced release of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6) in blood and brain of mice. In a rat model of endotoxin induced uveitis, ABI-4 (0.03-0.3mg/kg) demonstrated steroid-like efficacy in preventing leucocyte infiltration of the aqueous humor when administered 4h after LPS. LPS (0.32mg/kg×5days) caused a 30% upregulation of translocator protein (TSPO) binding which was prevented by co-administration of ABI-4 (0.32mg/kg). In a paradigm to assess motivation, LPS (0.32mg/kg) reduced the number of rewards received, whereas the effect was significantly blunted in mice dosed with ABI-4 (P<0.05) or in PDE4B-/- mice. PDE4B was also shown to modulate brain and plasma levels of TNF-α and IL-1ß in aged mice. Aged mice dosed chronically with ABI-4 (0.32mg/kg) as well as aged PDE4B-/- mice, had significantly lower levels of TNF-α and IL-1ß in brain and plasma relative to vehicle treated or PDE4+/+ mice. Together these data demonstrate that the PDE4D sparing, PDE4 inhibitor, ABI-4 retains potency and efficacy in exerting anti-inflammatory effects. This mechanism warrants further investigation in human disorders involving neuroinflammation.

Reaccumulation of globotriaosylceramide in podocytes after agalsidase dose reduction in young Fabry patients.

BACKGROUND: Agalsidase-α 0.2 mg/kg every other week (eow) and agalsidase-ß 1.0 mg/kg/eow are licensed in Europe as equipotent treatment of the α-galactosidase deficiency in Fabry disease. This case series describes the effects of agalsidase dose adjustments in serial kidney biopsies in switch patients. METHODS: All treatment-naïve patients with classical Fabry disease in our centre started on agalsidase-ß 1.0 mg/kg/eow and subsequently switched to agalsidase-α 0.2 mg/kg/eow were included ( n = 3). The median age at enzyme replacement therapy start was 11 (range 7-18) years. Kidney biopsies were performed at baseline, after 5 years of agalsidase-ß 1.0 mg/kg/eow and after 3 subsequent years of agalsidase-α 0.2 mg/kg/eow. One patient was re-biopsied 2 years after reswitch to agalsidase-ß 1.0 mg/kg/eow. The scoring system of the International Scoring Group of Fabry Nephropathy was used. RESULTS: The patients completely cleared globotriaosylceramide (GL3) from mesangial and endothelial cells and partly cleared podocytes on agalsidase-ß 1.0 mg/kg/eow. Reaccumulation of GL3 in podocytes, but not in the mesangium or endothelium, occurred after 3 years of agalsidase-α 0.2 mg/kg/eow. Subsequent reduction of podocyte GL3 was observed in the single patient rebiopsied 2 years after reswitch to agalsidase-ß 1.0 mg/kg/eow. CONCLUSION: Partial clearance, reaccumulation and renewed partial clearance of podocyte GL3 deposits in serial kidney biopsies over 8-10 years were seen in parallel with agalsidase dose adjustments. Repeated kidney biopsies may impact therapeutic choices in Fabry disease.

Patients with Fabry Disease after Enzyme Replacement Therapy Dose Reduction and Switch-2-Year Follow-Up.

Because of the shortage of agalsidase-ß supply between 2009 and 2012, patients with Fabry disease either were treated with reduced doses or were switched to agalsidase-α. In this observational study, we assessed end organ damage and clinical symptoms with special focus on renal outcome after 2 years of dose-reduction and/or switch to agalsidase-α. A total of 89 adult patients with Fabry disease who had received agalsidase-ß (1.0 mg/kg body wt) for >1 year were nonrandomly assigned to continue this treatment regimen (regular-dose group, n=24), to receive a reduced dose of 0.3-0.5 mg/kg and a subsequent switch to 0.2 mg/kg agalsidase-α (dose-reduction-switch group, n=28), or to directly switch to 0.2 mg/kg agalsidase-α (switch group, n=37) and were followed-up for 2 years. We assessed clinical events (death, myocardial infarction, severe arrhythmia, stroke, progression to ESRD), changes in cardiac and renal function, Fabry-related symptoms (pain, hypohidrosis, diarrhea), and disease severity scores. Determination of renal function by creatinine and cystatin C-based eGFR revealed decreasing eGFRs in the dose-reduction-switch group and the switch group. The Mainz Severity Score Index increased significantly in these two groups (P=0.02 and P<0.001, respectively), and higher frequencies of gastrointestinal pain occurred during follow-up. In conclusion, after 2 years of observation, all groups showed a stable clinical disease course with respect to serious clinical events. However, patients under agalsidase-ß dose-reduction and switch or a direct switch to agalsidase-α showed a decline of renal function independent of the eGFR formula used.

Risk factors for severe clinical events in male and female patients with Fabry disease treated with agalsidase beta enzyme replacement therapy: Data from the Fabry Registry.

BACKGROUND: Fabry disease, an X-linked lysosomal storage disorder, causes intracellular accumulation of glycosphingolipids leading to progressive renal, cardiovascular, and cerebrovascular disease, and premature death. METHODS: This longitudinal Fabry Registry study analyzed data from patients with Fabry disease to determine the incidence and type of severe clinical events following initiation of enzyme replacement therapy (ERT) with agalsidase beta, as well as risk factors associated with occurrence of these events. Severe events assessed included chronic dialysis, renal transplantation, cardiac events, stroke, and death. RESULTS: The analyses included 969 male and 442 female Fabry patients. The mean age at first agalsidase beta infusion was 35 and 44, and median treatment follow-up 4.3years and 3.2years, respectively. Among males, cardiac events were the most common on-ERT events, followed by renal, stroke, and non-cardiac death. Among females, cardiac events were also most common followed by stroke and renal events. Patients with on-ERT events had significantly more advanced cardiac and renal disease at baseline as compared with patients without on-ERT events. Severe events were also associated with older age at ERT initiation (males and females), a history of pre-ERT events (females; approaching statistical significance in males), and a higher urinary protein/creatinine ratio (females). Approximately 65% of patients with pre-ERT events did not experience subsequent on-ERT events. Of patients without pre-ERT events, most (84% of males, 92% of females) remained event-free. CONCLUSIONS: Patients with on-ERT severe events had more advanced Fabry organ involvement at baseline than those without such events and patients who initiated ERT at a younger age had less residual risk of on-ERT events. The observed patterns of residual risk may aid clinicians in multidisciplinary monitoring of male and female patients with Fabry disease receiving ERT, and in determining the need for administration of adjunctive therapies.

Surges in proteinuria are associated with plasma GL-3 elevations in a young patient with classic Fabry disease.

UNLABELLED: Fabry disease is an X-linked glycosphingolipidosis caused by deficient synthesis of the enzyme α-galactosidase A, which results in accumulations of globotriaosylceramide (GL-3) in systemic tissues. Nephropathy is a dominant feature of Fabry disease. It still remains unclear how the nephropathy progresses. Recombinant agalsidase replacement therapy is currently the only approved, specific therapy for Fabry disease. The optimal dose of replacement enzyme also still remains unclear. The worldwide shortage of agalsidase-ß in 2009 forced dose reduction of administration. It showed that the proteinuria emerged like surges, followed by temporary plasma GL-3 elevations in the early stages of classic Fabry disease. Additionally, it also showed that 1 mg/kg of agalsidase-ß every other week could clear the GL-3 accumulations from podocytes and was required to maintain negative proteinuria and normal plasma GL-3 levels. CONCLUSION: This observation of a young patient with classic Fabry disease about 5 years reveals that the long-term, low-dose agalsidase-ß caused proteinuria surges, but not persistent proteinuria, followed by temporary plasma GL-3 elevations, and agalsidase-ß at 1 mg/kg every other week could clear accumulated GL-3 from podocytes and was required to maintain normal urinalysis and plasma GL-3 levels.

Enzyme replacement therapy for Anderson-Fabry disease.

BACKGROUND: Anderson-Fabry disease is an X-linked defect of glycosphingolipid metabolism. Progressive renal insufficiency is a major source of morbidity, additional complications result from cardio- and cerebro-vascular involvement. Survival is reduced among affected males and symptomatic female carriers.This is an update of a Cochrane review first published in 2010, and previously updated in 2013. OBJECTIVES: To evaluate the effectiveness and safety of enzyme replacement therapy compared to other interventions, placebo or no interventions, for treating Anderson-Fabry disease. SEARCH METHODS: We searched the Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register (date of the most recent search: 08 July 2016). We also searched 'Clinical Trials' on The Cochrane Library, MEDLINE, Embase and LILACS (date of the most recent search: 24 September 2015). SELECTION CRITERIA: Randomized controlled trials of agalsidase alfa or beta in participants diagnosed with Anderson-Fabry disease. DATA COLLECTION AND ANALYSIS: Two authors selected relevant trials, assessed methodological quality and extracted data. MAIN RESULTS: Nine trials comparing either agalsidase alfa or beta in 351 participants fulfilled the selection criteria.Both trials comparing agalsidase alfa to placebo reported on globotriaosylceramide concentration in plasma and tissue; aggregate results were non-significant. One trial reported pain scores measured by the Brief Pain Inventory severity, there was a statistically significant improvement for participants receiving treatment at up to three months, mean difference -2.10 (95% confidence interval -3.79 to -0.41; at up to five months, mean difference -1.90 (95% confidence interval -3.65 to -0.15); and at up to six months, mean difference -2.00 (95% confidence interval -3.66 to -0.34). There was a significant difference in the Brief Pain Inventory pain-related quality of life at over five months and up to six months, mean difference -2.10 (95% confidence interval -3.92 to -0.28) but not at other time points. Death was not an outcome in either of the trials.One of the three trials comparing agalsidase beta to placebo reported on globotriaosylceramide concentration in plasma and tissue and showed significant improvement: kidney, mean difference -1.70 (95% confidence interval -2.09 to -1.31); heart, mean difference -0.90 (95% confidence interval -1.18 to -0.62); and composite results (renal, cardiac, and cerebrovascular complications and death), mean difference -4.80 (95% confidence interval -5.45 to -4.15). There was no significant difference between groups for death; no trials reported on pain.Only two trials compared agalsidase alfa to agalsidase beta. One of them showed no significant difference between the groups regarding adverse events, risk ratio 0.36 (95% confidence interval 0.08 to 1.59), or any serious adverse events; risk ratio 0.30; (95% confidence interval 0.03 to 2.57).Two trials compared different dosing schedules of agalsidase alfa. One of them involved three different doses (0.2 mg/kg every two weeks; 0.1 mg/kg weekly and; 0.2 mg/kg weekly), the other trial evaluated two further doses to the dosage schedules: 0.4 mg/kg every week and every other week. Both trials failed to show significant differences with various dosing schedules on globotriaosylceramide levels. No significant differences were found among the schedules for the primary efficacy outcome of self-assessed health state, or for pain scores.One trial comparing agalsidase alfa to agalsidase beta showed no significant difference for any adverse events such as dyspnoea and hypertension.The methodological quality of the included trials was generally unclear for the random sequence generation and allocation concealment. AUTHORS' CONCLUSIONS: Trials comparing enzyme replacement therapy to placebo show significant improvement with enzyme replacement therapy in regard to microvascular endothelial deposits of globotriaosylceramide and in pain-related quality of life. There is, however, no evidence identifying if the alfa or beta form is superior or the optimal dose or frequency of enzyme replacement therapy. With regards to safety, adverse events (i.e., rigors, fever) were more significant in the agalsidase beta as compared to placebo. The long-term influence of enzyme replacement therapy on risk of morbidity and mortality related to Anderson-Fabry disease remains to be established. This review highlights the need for continued research into the use of enzyme replacement therapy for Anderson-Fabry disease.

A prospective 10-year study of individualized, intensified enzyme replacement therapy in advanced Fabry disease.

OBJECTIVES: To test the hypothesis that more frequent enzyme replacement therapy (ERT) slows the decline in kidney function in adult patients with Fabry disease. METHODS: A single center open label 10-year prospective clinical trial of 12 patients with advanced Fabry disease who, after having experienced an ongoing decline in renal function after 2-4 years of receiving ERT at the approved dose of 0.2 mg/kg agalsidase alfa every other week (EOW), were switched to weekly (EW) ERT at the same dose. We used linear regression to fit each individual patient's longitudinal estimated glomerular filtration rate (eGFR) record in order to compare the deterioration rates between EOW and EW ERT. RESULTS: For the entire group, mean slope on agalsidase alfa every 2 weeks was -7.92 ± 2.88 ml/min/1.73 m(2)/year and 3.84 ± 4.08 ml/min/1.73 m(2)/year on weekly enzyme infusions (p = 0.01, two-tailed paired t test). Three patients (25 %) completed the entire study with relatively preserved renal function while 50 % of patients reached end-stage renal disease (ESRD) during the 10 years of this study. The estimated average delay to ESRD was 13.8 years [n = 11; 95 % CI 0.66, 27]. One patient had a positive eGFR slope on weekly infusions while the patient with the highest antibody titer had a steeper slope after switching. Mean globotriaosylceramide concentrations in urine and plasma as well as urine protein excretion remained unchanged. CONCLUSIONS: Weekly enzyme infusions slow the decline of renal function in a subgroup of more severe patients thus showing that existing ERT can be further optimized.

Patients with Fabry disease after enzyme replacement therapy dose reduction versus treatment switch.

Because of the shortage of agalsidase-beta in 2009, many patients with Fabry disease were treated with lower doses or were switched to agalsidase-alfa. This observational study assessed end-organ damage and clinical symptoms during dose reduction or switch to agalsidase-alfa. A total of 105 adult patients with Fabry disease who had received agalsidase-beta (1.0 mg/kg body weight) for ≥1 year were nonrandomly assigned to continue this treatment regimen (regular-dose group, n=38), receive a reduced dose of 0.3-0.5 mg/kg (dose-reduction group, n=29), or switch to 0.2 mg/kg agalsidase-alfa (switch group) and were followed prospectively for 1 year. We assessed clinical events (death, myocardial infarction, severe arrhythmia, stroke, progression to ESRD); changes in cardiac, renal, and neurologic function; and Fabry-related symptoms (neuropathic pain, hypohidrosis, diarrhea, and disease severity scores). Organ function and Fabry-related symptoms remained stable in the regular-dose group. In contrast, estimated GFR decreased by about 3 ml/min per 1.73 m(2) (P=0.01) in the dose-reduction group, and the median albumin-to-creatinine ratio increased from 114 (0-606) mg/g to 216 (0-2062) mg/g (P=0.03) in the switch group. Furthermore, mean Mainz Severity Score Index scores and frequencies of pain attacks, chronic pain, gastrointestinal pain, and diarrhea increased significantly in the dose-reduction and switch groups. In conclusion, patients receiving regular agalsidase-beta dose had a stable disease course, but dose reduction led to worsening of renal function and symptoms. Switching to agalsidase-alfa is safe, but microalbuminuria may progress and Fabry-related symptoms may deteriorate.

Agalsidase benefits renal histology in young patients with Fabry disease.

The effect of early-onset enzyme replacement therapy on renal morphologic features in Fabry disease is largely unknown. Here, we evaluated the effect of 5 years of treatment with agalsidase alfa or agalsidase beta in 12 consecutive patients age 7-33 years (median age, 16.5 years). We performed renal biopsies at baseline and after 5 years of enzyme replacement therapy; 7 patients had additional biopsies after 1 and 3 years. After a median of 65 months, biopsy findings from all patients showed total clearance of glomerular endothelial and mesangial cell inclusions, and findings from 2 patients showed complete clearance of inclusions from epithelial cells of the distal tubule. The 4 patients who received the highest dose of agalsidase exhibited substantial clearance of podocyte inclusions, and the youngest patient had nearly complete clearance of these inclusions. Linear regression analysis showed a highly significant correlation between podocyte globotriaocylceramide clearance and cumulative agalsidase dose (r=0.804; P=0.002). Microalbuminuria normalized in five patients. In summary, long-term enzyme replacement therapy in young patients can result in complete globotriaocylceramide clearance of mesangial and glomerular endothelial cells across all dosage regimens, and clearance of podocyte inclusions is dose-dependent.

Effects of switching from agalsidase-α to agalsidase-ß on biomarkers, renal and cardiac parameters, and disease severity in fabry disease forming neutralizing antidrug antibodies: a case report.

Fabry disease is an X-linked hereditary disorder caused by deficient α-galactosidase A (GLA) activity. Patients with Fabry disease are often treated with enzyme replacement therapy (ERT). However, ERT often induces the formation of neutralizing antidrug antibodies (ADAs), which may impair the therapeutic efficacy. Here, we report the case of a 32-year-old man with Fabry disease and resultant neutralizing ADAs who was treated by switching from agalsidase-α to agalsidase-ß. We monitored biomarkers, such as plasma globotriaosylsphingosine (lyso-Gb3), urinary globotriaosylceramide (Gb3), urinary mulberry bodies, renal and cardiac parameters, and disease severity during the treatment period. Although plasma lyso-Gb3 and urinary Gb3 levels quickly decreased within two months after the initiation of ERT with agalsidase-α, they gradually increased thereafter. The urinary mulberry bodies continued to appear. Both the ADA titer and serum mediated GLA inhibition rates started to increase after two months. Moreover, 3.5 years after ERT, the vacuolated podocyte area in the renal biopsy decreased slightly from 23.1 to 18.9%. However, plasma lyso-Gb3 levels increased, and urinary Gb3, mulberry body levels, and ADA titers remained high. Therefore, we switched to agalsidase-ß which reduced, but did not normalize, plasma lyso-Gb3 levels and stabilized renal and cardiac parameters. Disease severity was attenuated. However, urinary Gb3 and mulberry body levels did not decrease noticeably in the presence of high ADA titers. The kidneys take up a small amount of the administered recombinant enzyme, and the clearance of Gb3 that has accumulated in the kidney may be limited despite the switching from agalsidase-α to agalsidase-ß.

Changes in plasma and urine globotriaosylceramide levels do not predict Fabry disease progression over 1 year of agalsidase alfa.

PURPOSE: Globotriaosylceramide concentrations were assessed as potential predictors of change from baseline after 12 months by estimated glomerular filtration rate and left-ventricular mass index using pooled data from three randomized, placebo-controlled agalsidase alfa trials and open-label extensions of patients with Fabry disease. METHODS: Males (aged 18 years or older) with Fabry disease received agalsidase alfa (0.2 mg/kg every other week for 12 months). A backward-elimination approach evaluated potential predictors (baseline estimated glomerular filtration rate and left-ventricular mass index; age at first dose; baseline and change from baseline at 12 months of globotriaosylceramide (urine, plasma); urine protein excretion; and systolic and diastolic blood pressure). Subgroups included patients randomized to placebo or agalsidase alfa (double-blind phase), then to agalsidase alfa (open-label extensions; placebo→agalsidase alfa or agalsidase alfa→agalsidase alfa, respectively) and stage 2/3 chronic kidney disease patients. RESULTS: Baseline estimated glomerular filtration rate, age at first dose, baseline urine globotriaosylceramide excretion, and baseline and change from baseline urine protein excretion significantly predicted change from baseline estimated glomerular filtration rate in the analysis population (N = 73; all P<0.05), although not in all subgroups. Change from baseline urine and plasma globotriaosylceramide (baseline and change from baseline) concentrations did not predict change from baseline estimated glomerular filtration rate. No predictors of left-ventricular mass index were significant. CONCLUSION: Changes in globotriaosylceramide concentrations do not appear to be useful biomarkers for prediction of Fabry disease-related changes in estimated glomerular filtration rate or left-ventricular mass index.