Updated Evaluation of Agalsidase Alfa Enzyme Replacement Therapy for Patients with Fabry Disease: Insights from Real-World Data

The clinical use of agalsidase alfa as enzyme replacement therapy (ERT) for Fabry disease (FD) has spread since 2001, and a large body of evidence of its effectiveness has been collected. This review presents the clinical and laboratory results achieved with agalsidase alfa, which has been published in the literature. Agalsidase alfa infusion slows down or stops the progression of renal damage, expressed by reduction or stabilization of the annual decline of the glomerular filtration rate; yearly decrease of glomerular filtration rate (slope) sometimes is reduced until its stabilization. ERT prevents or reduces the occurrence of hypertrophic cardiomyopathy or slows the increase over time if it is already present. Moreover, regarding neurological manifestations, ERT improves neuropathic pain and quality of life, and recent data indicated that it may also prevent the burden of cerebrovascular disease. In addition to ERT's clinical benefits, crucial topics like the most appropriate time to start therapy and the role of anti-drug antibodies (ADA) are analyzed. Treatment with agalsidase alfa in patients with FD substantially improves their outcomes and enhances their quality of life in patients with FD.

Major cardiovascular adverse events in Fabry disease patients receiving agalsidase alfa

Cardiovascular mortality (CVM) has become the major contributor to overall Fabry disease (FD) mortality in the enzyme replacement therapy (ERT) era. Our objectives were to describe causes and potential predictors of mortality in FD adult patients in Argentina, and to assess risk of major adverse cardiovascular events (MACE) in the ERT era. We retrospectively studied 93 consecutive patients treated with alphagalactosidase A (median follow up: 9.5 years from start of ERT). Mean age at ERT starting was 35 ± 16.3 years. Prevalence of cardiomyopathy and renal disease reached 47% and 41%, respectively. Eleven subjects (11.8%, 95% CI: 5-18%) died during follow up (1.24/100 patient-years). Mean overall survival was 71 years (95% CI: 66-75 years). Seven cases were considered as CVM; main causes were sudden death and stroke. Risk of MACE was 14% (95% CI: 6.9-21.1%; 1.47 events/100 patient-years from start of ERT). All but 2 subjects had at least one comorbid cardiovascular risk factor; however, 86% of patients remained free of MACE during follow-up. CVM remained low and our study was underpowered for detection of predictors of mortality, but it is worth noting that age at diagnosis and ERT starting, left ventricular mass index and renal disease trended to correlate with CVM. Prevalence of hypertension, diabetes and dyslipidemia were lower in FD patients when compared to population level data. As in the Argentinean general population, CVM was the leading cause of mortality among this cohort of consecutive FD patients treated with agalsidase alfa.

Fabry Disease Therapy: State-of-the-Art and Current Challenges

Fabry disease (FD) is a lysosomal storage disorder caused by mutations of the GLA gene that lead to a deficiency of the enzymatic activity of α-galactosidase A. Available therapies for FD include enzyme replacement therapy (ERT) (agalsidase alfa and agalsidase beta) and the chaperone migalastat. Despite the large body of literature published about ERT over the years, many issues remain unresolved, such as the optimal dose, the best timing to start therapy, and the clinical impact of anti-drug antibodies. Migalastat was recently approved for FD patients with amenable GLA mutations; however, recent studies have raised concerns that "in vitro" amenability may not always reflect "in vivo" amenability, and some findings on real-life studies have contrasted with the results of the pivotal clinical trials. Moreover, both FD specific therapies present limitations, and the attempt to correct the enzymatic deficiency, either by enzyme exogenous administration or enzyme stabilization with a chaperone, has not shown to be able to fully revert FD pathology and clinical manifestations. Therefore, several new therapies are under research, including new forms of ERT, substrate reduction therapy, mRNA therapy, and gene therapy. In this review, we provide an overview of the state-of-the-art on the currently approved and emerging new therapies for adult patients with FD.

Effects of Baseline Left Ventricular Hypertrophy and Decreased Renal Function on Cardiovascular and Renal Outcomes in Patients with Fabry Disease Treated with Agalsidase Alfa: A Fabry Outcome Survey Study

PURPOSE

The initiation of enzyme-replacement therapy prior to the occurrence of substantial and irreversible organ damage in patients with Fabry disease is of critical importance. The Fabry Outcome Survey is an international disease registry of patients with a confirmed diagnosis of Fabry disease. In this study, data from the Fabry Outcome Survey were used for the assessment of the risks for cardiovascular and renal events in patients who received agalsidase alfa treatment.

METHODS

Eligible patients were males and females aged ≥18 years with Fabry disease treated with agalsidase alfa. Cardiovascular events included myocardial infarction, left ventricular hypertrophy (LVH), heart failure, arrhythmia, conduction abnormality, and cardiac surgery. Renal events included dialysis, transplantation, and renal failure. Kaplan-Meier curves and log-rank tests were used for comparing event-free probabilities and time to first cardiovascular or renal event, from agalsidase alfa initiation to a maximum of 120 months, in patients with LVH versus normal left ventricular mass index (LVMI; ≤50 g/m^2.7 in males and ≤48 g/m^2.7 in females) at treatment initiation (baseline), and in patients with a low estimated glomerular filtration rate (eGFR; <90 mL/min/1.73 m²) versus normal eGFR at baseline. Multivariate Cox regression analysis was used for examining the association between key study variables and the risks for cardiovascular and renal events.

FINDINGS

Among the 560 patients (269 males; 291 females) with available LVMI data, 306 (55%) had LVH and 254 (45%) had normal LVMI at baseline. The risk for a cardiovascular event was higher in the subgroup with LVH versus normal LVMI at baseline (hazard ratio [HR] = 1.57; 95% CI, 1.21-2.05; P < 0.001), but the risk for a renal event was similar between the 2 subgroups (HR = 1.90; 95% CI, 0.94-3.85; P = 0.074). Among the 1093 patients (551 males; 542 females) with available eGFR data, 433 (40%) had a low eGFR and 660 (60%) had a normal eGFR at baseline. The subgroup with a low eGFR at baseline had a significantly higher risk for a cardiovascular event (HR = 1.33; 95% CI, 1.04-1.70; P = 0.021) or a renal event (HR = 5.88; 95% CI, 2.73-12.68; P < 0.001) compared with patients with a normal eGFR at baseline.

IMPLICATIONS

In the present study, the presence of LVH and/or reduced renal function at agalsidase alfa initiation was associated with a significantly higher risk for a cardiovascular or renal event, indicating that cardiovascular and renal pathologies in Fabry disease may be inter-related. Early initiation of agalsidase alfa treatment prior to the onset of severe organ damage may improve outcomes. ClinicalTrials.gov identifier: NCT03289065.

Analysis of Renal and Cardiac Outcomes in Male Participants in the Fabry Outcome Survey Starting Agalsidase Alfa Enzyme Replacement Therapy Before and After 18 Years of Age

Purpose

To determine the impact of initiating enzyme replacement therapy (ERT) with agalsidase alfa early in the course of Fabry disease, we evaluated renal and cardiac outcomes for ≤10 years after ERT initiation in males from the Fabry Outcome Survey (FOS).

Patients and Methods

Male patients from FOS were stratified into three cohorts by age at ERT initiation: ≤18 years (cohort 1), >18 and ≤30 years (cohort 2), and >30 years (cohort 3). Analysis included age at symptom onset, diagnosis, and ERT initiation; ERT duration; FOS-Mainz Severity Score Index (FOS-MSSI); estimated glomerular filtration rate (eGFR); proteinuria level; and left ventricular mass indexed to height (LVMI). Mixed-effect models estimated renal and cardiac outcomes during follow-up between and within cohorts.

Findings

The analysis included 560 male patients: 151 (27.0%) in cohort 1, 155 (27.7%) in cohort 2, and 254 (45.4%) in cohort 3. Mean±SD duration of ERT for cohorts 1, 2, and 3 was 6.3±4.3, 8.6±4.9, and 7.9±4.9 years, respectively. Mean±SD baseline FOS-MSSI scores increased with age from 9.8±7.2 in cohort 1 to 24.7±11.4 in cohort 3. Cohort 3 showed the lowest baseline mean±SD value for eGFR (87.1±29.0 mL/min/1.73m²) and highest baseline mean±SD values for proteinuria (801.9±952.6 mg/day) and LVMI (56.7±16.0 g/m^2.7) among the three cohorts. Evaluation of mean annual rates of change in eGFR, proteinuria, and LVMI revealed no significant differences in any parameter for cohort 1. For cohort 2, proteinuria and LVMI remained stable, whereas eGFR significantly deteriorated annually (–1.12 mL/min/1.73m²; P<0.001). Cohort 3 demonstrated significant annual deteriorations in eGFR (–2.60 mL/min/1.73m²; P<0.001), proteinuria (+34.10 mg/day; P<0.001), and LVMI (+0.59 g/m^2.7; P=0.001).

Implications

Renal and/or cardiac disease progression appears attenuated in patients starting ERT in childhood or early adulthood versus patients starting ERT in later adulthood. These findings support early ERT initiation in Fabry disease. ClinicalTrials.gov identifier: NCT03289065.

Cardio- Renal Outcomes With Long- Term Agalsidase Alfa Enzyme Replacement Therapy: A 10- Year Fabry Outcome Survey (FOS) Analysis

Purpose

Following the publication of 5-year agalsidase alfa enzyme replacement therapy (ERT) outcomes data from the Fabry Outcome Survey (FOS), 10-year data were analyzed.

Patients and methods

FOS (ClinicalTrials.gov identifier: NCT03289065) data (April 2001 to August 2018) were retrospectively analyzed. Estimated glomerular filtration rate (eGFR) and left ventricular mass indexed to height (LVMI) were analyzed after treatment start (baseline) for patients with ≥3 measurements, including baseline and year 10.

Results

Median (range) age (years) of the evaluable treated renal cohort at treatment start was 48.8 (17.9–67.3) for females (n=62), 34.4 (18.0–66.8) for males (n=90). With eGFR ≥60 mL/min/1.73 m² at baseline, mean (95% CI) rate of eGFR change (eGFR/year) over 10 years was relatively stable in females (n=52; −0.55 [−1.12, +0.01]) and slightly declined in males (n=79; −1.99 [−2.45, −1.54]). With impaired kidney function (eGFR <60 mL/min/1.73 m²) at baseline, mean (95% CI) eGFR/year was stable in females (n=10; −0.14 [−1.43, +1.15]) and slightly declined in males (n=11; −2.79 [−4.01, −1.56]) over 10 years. Median (range) age (years) of the evaluable treated cardiac cohort at treatment start was 46.7 (3.7–67.3) for females (n=34), 28.2 (4.0–54.2) for males (n=35). With left ventricular hypertrophy (LVH; LVMI >48 g/m^2.7 in females, >50 g/m^2.7 in males) at baseline, mean (95% CI) LVMI/year slightly increased over 10 years in females (n=18; +1.51 [+0.91, +2.12]) and males (n=14; +0.87 (+0.19, +1.55). Without LVH at baseline, mean (95% CI) LVMI/year was stable in females (n=16; +0.52 [−0.13, +1.17]) and males (n=21; +0.57 [+0.02, +1.13]) over 10 years.

Conclusion

Agalsidase alfa-treated patients with 10-year FOS data and preserved kidney function and/or normal LVMI at baseline remained largely stable; those with decreased kidney function or LVH at baseline experienced modest declines in renal function and/or increases in LVMI.

Altered immune phenotypes in subjects with Fabry disease and responses to switching from agalsidase alfa to agalsidase beta

Fabry disease (FD) is a rare X-linked genetic disorder caused by mutations in the GLA gene encoding the lysosomal enzyme, α-galactosidase A (α-gal A). The mutations lead to lack of or faulty enzyme causing accumulation of globotriaosylceramide (Gb3) and related glycosphingolipids including globotriaosylsphingosine (lyso-Gb₃). Treatment options for FD include enzyme replacement therapy. There are two different recombinant α-gal A enzymes, where agalsidase beta has been approved by FDA for use in the USA while both agalsidase beta and agalsidase alfa are being prescribed in many other countries. Several FD patients in the USA were switched to agalsidase alfa for a certain period of time due to supply shortage of agalsidase beta but were switched back to agalsidase beta upon availability. Due to the fact that some glycolipids may serve as antigens, various immune abnormalities have been associated with several lysosomal storage disorders (LSDs). In the present clinical study we evaluated alterations in peripheral immune cell subsets in patients with FD (n=27) compared to healthy control group (n=27). Patients with FD showed persistent T cell associated abnormalities, including skewed T helper to cytotoxic T cell ratio and elevated fraction of memory T cells and expression of activation markers on T cell subsets. Further, the study elucidated the effect of switching from agalsidase alfa to agalsidase beta on immune system as well as other clinical markers. While there was relative decrease in plasma lyso-Gb₃ as well as urine lyso-Gb₃ over time, their levels remained above the reference values. The immune abnormalities did not correlate with gender, age or lyso-Gb₃ levels, indicating that these persistent changes were inherent to FD irrespective of the extent of substrate accumulation.

[Genetic causes of stroke in young patients]

The paper addresses genetic causes of stroke: MELAS, antiphospholipid syndrome, CADASIL, Fabry disease. The etiology and pathogenesis, symptoms, diagnosis, treatment methods of these diseases are described.

The effect of enzyme replacement therapy on clinical outcomes in male patients with Fabry disease: A systematic literature review by a European panel of experts

Background

Enzyme replacement therapy (ERT) with recombinant human α-galactosidase has been available for the treatment of Fabry disease since 2001 in Europe and 2003 in the USA. Treatment outcomes with ERT are dependent on baseline patient characteristics, and published data are derived from heterogeneous study populations.

Methods

We conducted a comprehensive systematic literature review of all original articles on ERT in the treatment of Fabry disease published up until January 2017. This article presents the findings in adult male patients.

Results

Clinical evidence for the efficacy of ERT in adult male patients was available from 166 publications including 36 clinical trial publications. ERT significantly decreases globotriaosylceramide levels in plasma, urine, and in different kidney, heart, and skin cell types, slows the decline in estimated glomerular filtration rate, and reduces/stabilizes left ventricular mass and cardiac wall thickness. ERT also improves nervous system, gastrointestinal, pain, and quality of life outcomes.

Conclusions

ERT is a disease-specific treatment for patients with Fabry disease that may provide clinical benefits on several outcomes and organ systems. Better outcomes may be observed when treatment is started at an early age prior to the development of organ damage such as chronic kidney disease or cardiac fibrosis. Consolidated evidence suggests a dose effect. Data described in male patients, together with female and paediatric data, informs clinical practice and therapeutic goals for individualized treatment.

Evaluating enzyme replacement therapies for Anderson-Fabry disease: commentary on a recent report

Anderson-Fabry disease (AFD) is a rare lysosomal storage disorder. Randomized controlled clinical trials (RCTs) are preferred as the highest category of evidence, but limited availability of robust evidence in rare diseases may necessitate the use of less rigorous evidence. An analysis of cohort studies of enzyme replacement therapies for AFD published in 2017 by El Dib and coworkers made treatment recommendations that contradict previously published findings from RCTs and a systematic Cochrane review. Our commentary outlines concerns regarding selection criteria and statistical methods with their analysis.

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 (β: −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.

Gender Differences in the Application of Spanish Criteria for Initiation of Enzyme Replacement Therapy for Fabry Disease in the Fabry Outcome Survey

Both male/female patients with Fabry disease (FD) may receive enzyme replacement therapy (ERT). Previously published analyses of the Fabry Outcome Survey (FOS; Shire-sponsored) database suggested gender differences in timing of ERT initiation. We assessed alignment of criteria for ERT initiation in the Spanish adult population included in FOS with recommendations of a Spanish national consensus. This retrospective analysis examined baseline clinical data of 88 adults (49 females) enrolled in the FOS database up to August 2014. Thirty-five (39.8%) patients were not receiving ERT: five (12.8%) males and 30 (61.2%) females. Baseline disease severity on the FOS-derived Mainz Severity Score Index was lower in untreated males (median (interquartile range), 0.0 (0.0–1.0)) than treated males (TM; 15.0 (7.5–26.5)), and was similar in untreated and treated females. The percentage of untreated females with at least one criterion for treatment initiation was 76.7% versus 100.0% of treated females (p = 0.0340) and 97.1% (p = 0.0210) of TM. In discordance with Spanish consensus recommendations, a substantial number of females with evidence of FD who might benefit from ERT have not yet initiated treatment. These results suggest unequal gender perceptions with respect to ERT initiation in Spain.

An open-label clinical trial of agalsidase alfa enzyme replacement therapy in children with Fabry disease who are naïve to enzyme replacement therapy

Background

Following a drug manufacturing process change, safety/efficacy of agalsidase alfa were evaluated in enzyme replacement therapy (ERT)-naïve children with Fabry disease.

Methods

In an open-label, multicenter, Phase II study (HGT-REP-084; Shire), 14 children aged ≥7 years received 0.2 mg/kg agalsidase alfa every other week for 55 weeks. Primary endpoints: safety, changes in autonomic function (2-hour Holter monitoring). Secondary endpoints: estimated glomerular filtration rate, left ventricular mass index (LVMI), midwall fractional shortening, pharmacodynamic parameters, and patient-reported quality-of-life.

Results

Among five boys (median 10.2 [range 6.7, 14.4] years) and nine girls (14.8 [10.1, 15.9] years), eight patients experienced infusion-related adverse events (vomiting, n=4; nausea, n=3; dyspnea, n=3; chest discomfort, n=2; chills, n=2; dizziness, n=2; headache, n=2). One of these had several hypersensitivity episodes. However, no patient discontinued for safety reasons and no serious adverse events occurred. One boy developed immunoglobulin G (IgG) and neutralizing antidrug antibodies. Overall, no deterioration in cardiac function was observed in seven patients with low/abnormal SDNN (standard deviation of all filtered RR intervals; <100 ms) and no left ventricular hypertrophy: mean (SD) baseline SDNN, 81.6 (20.9) ms; mean (95% confidence interval [CI]) change from baseline to week 55, 17.4 (2.9, 31.9) ms. Changes in SDNN correlated with changes in LVMI (r=−0.975). No change occurred in secondary efficacy endpoints: mean (95% CI) change from baseline at week 55 in LVMI, 0.16 (−3.3, 3.7) g/m^2.7; midwall fractional shortening, −0.62% (−2.7%, 1.5%); estimated glomerular filtration rate, 0.15 (−11.4, 11.7) mL/min/1.73 m²; urine protein, −1.8 (−6.0, 2.4) mg/dL; urine microalbumin, 0.6 (−0.5, 1.7) mg/dL; plasma globotriaosylceramide (Gb₃), −5.71 (−10.8, −0.6) nmol/mL; urinary Gb₃, −1,403.3 (−3,714.0, 907.4) nmol/g creatinine, or clinical quality-of-life outcomes.

Conclusion

Fifty-five weeks’ agalsidase alfa ERT at 0.2 mg/kg every other week was well tolerated. Disease progression may be slowed when ERT is started prior to major organ dysfunction.

Trial registration

https://ClinicalTrials.gov identifier NCT01363492.

Fabry disease and enzyme replacement therapy in classic patients with same mutation: different formulations--different outcome?

We describe the results of the multidisciplinary evaluation in patients with Fabry disease and the same genetic mutation and their outcomes using different approved enzyme replacement therapy (ERT). We measured baseline data and serial results of neuropathic pain assessment and renal, cardiac and cerebrovascular functioning. Pain scale showed improvement in all male cases treated with agalsidasa beta. A mild improvement was detected in agalsidasa alfa-treated patients after 1 year with posterior increase. During the agalsidase beta shortage, two male patients were switched to agalsidasa alfa, after 1 year both cases presented an increase in scale values. Renal evolution showed a tendency toward a decrease in proteinuria in patients using agalsidase beta and worsening with agalsidase alfa. We found improvement in two females using agalsidase beta and no changes in the other cases regarding cardiac functioning. Brain magnetic resonance imaging (MRI) showed increase of white matter lesions in four patients. Improvement and stabilization in neuropathic pain, renal and cardiac functioning and brain MRI were found mainly in patients treated with agalsidase beta. Following the reported recommendations on reintroduction of agalsidase beta after the enzyme shortage, we decided to switch all patients to agalsidase beta.

Clinical observations on enzyme replacement therapy in patients with Fabry disease and the switch from agalsidase beta to agalsidase alfa

BACKGROUND

Fabry disease is an X-linked inherited lysosomal storage disease that can be treated with the enzymes of agalsidase beta (Fabrazyme) and agalsidase alfa (Replagal). Since June 2009, viral contamination of Genzyme's production facility has resulted in a worldwide shortage of agalsidase beta, leading to the switch to agalsidase alfa for patients with Fabry disease in Taiwan.

METHODS

The medical records were retrospectively reviewed for nine male patients with Fabry disease from the start of agalsidase beta treatment until the switch to agalsidase alfa for at least 1 year.

RESULTS

After 12-112 months of enzyme replacement therapy (ERT), decreased plasma globotriaosylsphingosine (lyso-Gb3) was found in five out of seven patients, indicating improvement in disease severity. Among the six patients with available echocardiographic data at baseline and after ERT, all six experienced reductions of left ventricular mass index. Renal function, including microalbuminuria and estimated glomerular filtration rate, showed stability after ERT. Mainz Severity Score Index scores revealed that all nine patients remained stable at 12 months after switching to agalsidase alfa. ERT improved or stabilized cardiac status and stabilized renal function, while reducing plasma lyso-Gb3. ERT was well tolerated, even among the three patients who had hypersensitivity reactions.

CONCLUSION

The switch of ERT from agalsidase beta to agalsidase alfa appears to be safe after 1 year of follow-up for Taiwanese patients with Fabry disease.

Update on role of agalsidase alfa in management of Fabry disease

Fabry disease (FD) is an X-linked lysosomal storage disorder that affects both men and women. The manifestations of this heterogeneous disease are multisystemic and progressive. Prior to the development of enzyme replacement therapy, the management and treatment for Fabry disease was largely nonspecific and supportive. Because enzyme replacement therapy became commercially available in 2001, a variety of clinical benefits in Fabry patients have been consistently reported, including improved renal pathology and cardiac function, and reduced severity of neuropathic pain and improved pain-related quality of life. This update focuses on published data on the efficacy and tolerability of enzyme replacement therapy with agalsidase alfa, and gives a brief overview on some of the outstanding management issues in the treatment of this complex disease.

Agalsidase alfa for enzyme-replacement therapy in Fabry disease

Fabry disease is an X-linked lysosomal storage disorder that is caused by a deficiency in the enzyme α-galactosidase A. Manifestations emerge during childhood, including neuropathic pain, hypohidrosis and gastrointestinal problems. Major organ involvement typically occurs during adulthood and includes progressive kidney dysfunction, cardiomyopathy and valve disease, and stroke. Enzyme-replacement therapy with agalsidase alfa has been available since 2001 and is associated with clinical benefit in adult men and women, as well as in children, with Fabry disease. The responses to agalsidase alfa include reduction in the severity of neuropathic pain, stabilization of kidney function and reduction in left ventricular mass in patients with baseline left ventricular hypertrophy. Several issues, including when to initiate treatment and whether long-term treatment will extend survival, remain to be answered. This article covers the clinical development of agalsidase alfa and the postmarketing reports of its safety and effectiveness.

Agalsidase alfa (Replagal) in the treatment of Anderson-Fabry disease

Anderson-Fabry disease (AFD) is an X-linked storage disorder caused by a deficiency of the lysosomal hydrolase a-galactosidase A (AGAL) and the resultant accumulation of its glycosphingolipid substrate (Gb3) in several tissue types. Major morbidity and reduced life expectancy among affected individuals are a consequence of renal, cardiac and cerebrovascular involvement. Symptomatic males and females with AFD have been described, although the onset of clinical manifestations may be delayed and more variable among the latter patient group, partly attributed to lyonization. Agalsidase alfa (Replagal()) is a recombinant formulation of human AGAL which has been demonstrated to modify the course of AFD in treated patients. Factors that may influence clinical outcomes include disease stage at the point of treatment initiation and antibody formation. There is incomplete understanding of AFD pathophysiology. Early diagnosis and timely intervention may be essential. The use of adjunctive therapies, directed at risk reduction (eg, aspirin for stroke prophylaxis), require careful scrutiny, but such agents are likely to be vital components of a comprehensive approach to patient care. Long-term studies may clarify the optimal dose and frequency of enzyme administration. Meanwhile, budding strategies such as chaperone-mediated enzyme enhancement may offer the potential for an alternative or multimodality approach to the management of AFD.

Agalsidase alfa therapy for Fabry disease

Fabry disease is a lysosomal storage disorder that results in neuropathic pain, progressive renal dysfunction, cardiomyopathy and stroke in affected individuals. The disease is caused by mutations in the GLA gene coding for α galactosidase A. The resulting deficiency of this enzyme causes accumulation of neutral glycosphingolipids in various tissues. Recombinant human agalsidase alfa has been developed to treat patients with Fabry disease. Preliminary data on this form of enzyme replacement therapy suggest that it improves pain, stabilizes renal function and improves cardiac hypertrophy in some patients. More data are needed on the ability of this therapy to prevent cardiac events, stroke and death.