Onset and progression of the Anderson-Fabry disease related cardiomyopathy

The beneficial effects of long-term enzyme replacement therapy on cardiac involvement in Japanese Fabry patients

Fabry disease is a hereditary disorder that occurs due to the reduction or absence of alpha-galactosidase A activity, which leads to cardiac involvement including left ventricular hypertrophy (LVH). Enzyme replacement therapy (ERT) provides better patient outcomes by preventing serious complications. However, there have been very few studies on the long-term effects of ERT on the cardiac manifestations in Japanese Fabry patients. We retrospectively analyzed the data from the medical records of 42 Fabry patients (male, n = 17; female, n = 25) who were followed at Jikei University Hospital, and in whom the long-term effects of ERT could be evaluated (median follow-up period: male, 11 years; female, 8 years). The slope of the left ventricular mass (LVM) increase was 3.02 ± 3.41 g/m²/year in males and 1.69 ± 2.73 g/m²/year in females. In a subgroup analysis, the slopes of males with and without LVH did not differ to a statistically significant extent; however, the slope in female patients without LVH was significantly smaller than that of female patients with LVH. We then compared our data to the natural historical data that have previously been reported. In comparison to the previously reported data, we found a significant reduction in the LVM changes (g/height^2.7/year) of patients who received long-term ERT (male, 4.07 ± 1.03 to 1.25 ± 1.39; female, 2.31 ± 0.81 to 0.78 ± 1.23). Long-term ERT effectively prevents LVH in Fabry patients. This effect was also observed in the patients with LVH prior to the initiation of ERT.

Time of Anderson-Fabry Disease Detection and Cardiovascular Presentation

Background

Anderson-Fabry disease is an X-linked inherited disease, which manifests in a different manner depending on gender and genotype. Making a working diagnosis of Anderson-Fabry disease is difficult because of several reasons: (a) that it is a multiorgan disease with wide variety of phenotypes, (b) different timelines of presentation, (c) gender differences, and (d) possible coexistence with other comorbidities. Late-onset/cardiac type of presentation with minimal involvement of other organs can additionally make diagnosis difficult.

Aim

To describe different cardiac manifestations at different time points in the course of the disease: (1) 72-year-old female (echocardiography detection), heterozygote, significant left and mild right ventricular hypertrophy; (2) 62-year-old male (echocardiography detection), hemizygote, left ventricular hypertrophy, implanted cardiac pacemaker, a performed percutaneous coronary intervention after myocardial infarction, degenerative medium degree aortic valve stenosis; (3) 45-year-old female (asymptomatic/family screening), heterozygote, thickened mitral papillary muscle, mild left ventricular hypertrophy, first degree diastolic dysfunction; and (4) 75-year-old female (symptomatic/family screening), heterozygote, cardiomyopathy with reduced left ventricular ejection fraction after heart surgery (mitral valve annuloplasty and plastic repair of the tricuspid valve).

Conclusion

All patients have Anderson-Fabry disease but with different clinical presentations depending on the gender, the type of mutation, and the time of detection. All these features can make the patients' profiles unique and delay the time of detection.

Fabry disease revisited: Management and treatment recommendations for adult patients

Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the GLA gene leading to deficient α-galactosidase A activity, glycosphingolipid accumulation, and life-threatening complications. Phenotypes vary from the "classic" phenotype, with pediatric onset and multi-organ involvement, to later-onset, a predominantly cardiac phenotype. Manifestations are diverse in female patients in part due to variations in residual enzyme activity and X chromosome inactivation patterns. Enzyme replacement therapy (ERT) and adjunctive treatments can provide significant clinical benefit. However, much of the current literature reports outcomes after late initiation of ERT, once substantial organ damage has already occurred. Updated monitoring and treatment guidelines for pediatric patients with Fabry disease have recently been published. Expert physician panels were convened to develop updated, specific guidelines for adult patients. Management of adult patients depends on 1) a personalized approach to care, reflecting the natural history of the specific disease phenotype; 2) comprehensive evaluation of disease involvement prior to ERT initiation; 3) early ERT initiation; 4) thorough routine monitoring for evidence of organ involvement in non-classic asymptomatic patients and response to therapy in treated patients; 5) use of adjuvant treatments for specific disease manifestations; and 6) management by an experienced multidisciplinary team.

Comparison of Cardiac Magnetic Resonance Imaging and Echocardiography in Assessment of Left Ventricular Hypertrophy in Fabry Disease

BACKGROUND

Cardiac hypertrophy in Fabry disease can be assessed using the left ventricular mass index (LVMI) with either echocardiography (LVMI-ECHO) or magnetic resonance imaging (LVMI-CMR).

METHODS

A retrospective case series of patients with Fabry disease in Alberta involved a cross-sectional analysis of 32 patients and a longitudinal analysis of 14 of these patients with at least 4 serial CMR measurements.

RESULTS

The cross-sectional analysis showed the mean LVMI-ECHO was 97.8 ± 26.0 g/m², which was higher compared with LVMI-CMR at 81.1 ± 26.9 g/m² with a mean bias of 16.7 g/m² (P < 0.001). In the longitudinal analysis, LVMI-ECHO was higher, with an estimated marginal mean of 96.21 ± 6.13 (mean ± standard error of the mean [SEM]) compared with 71.18 ± 5.99 for LVMI-CMR (P < 0.01; generalized estimating equations). There was an association between an increase in LVMI-CMR over time with the presence of cardiac fibrosis, and patients treated with enzyme replacement therapy (ERT) had slower increases than those without therapy. LVMI-ECHO failed to detect these associations owing to the higher variability and tendency to overestimate the LVMI.

CONCLUSIONS

We propose the preferred method for measuring LVMI is CMR in patients with Fabry disease.

Interleukin-18 deteriorates Fabry cardiomyopathy and contributes to the development of left ventricular hypertrophy in Fabry patients with GLA IVS4+919 G>A mutation

RATIONALE

A high incidence of GLA IVS4+919 G>A mutation in patients with Fabry disease of the later-onset cardiac phenotype, has been reported in Taiwan. However, suitable biomarkers or potential therapeutic surrogates for Fabry cardiomyopathy (FC) in such patients under enzyme replacement treatment (ERT) remain unknown.

OBJECTIVE

Using FC patients carrying IVS4+919 G>A mutation, we constructed an induced pluripotent stem cell (iPSC)-based disease model to investigate the pathogenetic biomarkers and potential therapeutic targets in ERT-treated FC.

RESULTS AND METHODS

The iPSC-differentiated cardiomyocytes derived from FC-patients (FC-iPSC-CMs) carried IVS4+919 G>A mutation recapitulating FC characteristics, including low α-galactosidase A enzyme activity, cellular hypertrophy, and massive globotriaosylceramide accumulation. Microarray analysis revealed that interleukin-18 (IL-18), a pleiotropic cytokine involved in various myocardial diseases, was the most highly upregulated marker in FC-iPSC-CMs. Meanwhile, IL-18 levels were found to be significantly elevated in the culture media of FC-iPSC-CMs and patients' sera. Notably, the serum IL-18 levels were highly paralleled with the progression of left ventricular hypertrophy in Fabry patients receiving ERT. Finally, using FC-iPSC-CMs as in vitro FC model, neutralization of IL-18 with specific antibodies combined with ERT synergistically reduced the secretion of IL-18 and the progression of cardiomyocyte hypertrophy in FC-iPSC-CMs.

CONCLUSION

Our data demonstrated that cardiac IL-18 and circulating IL-18 are involved in the pathogenesis of FC and LVH. IL-18 may be a novel marker for evaluating ERT efficacy, and targeting IL-18 might be a potential adjunctive therapy combined with ERT for the treatment of advanced cardiomyopathy in FC patients with IVS4+919 G>A mutation.

Human-Induced Pluripotent Stem Cell-Based Modeling of Cardiac Storage Disorders

PURPOSE OF REVIEW

The aim of this study is to review the published human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) models of cardiac storage disorders and to evaluate the limitations and future applications of this technology.

RECENT FINDINGS

Several cardiac storage disorders (CSDs) have been modeled using patient-specific hiPSC-CMs, including Anderson-Fabry disease, Danon disease, and Pompe disease. These models have shown that patient-specific hiPSC-CMs faithfully recapitulate key phenotypic features of CSDs and respond predictably to pharmacologic manipulation. hiPSC-CMs generated from patients with CSDs are representative models of the patient disease state and can be used as an in vitro system for the study of human cardiomyocytes. While these models suffer from several limitations, they are likely to play an important role in future mechanistic studies of cardiac storage disorders and the development of targeted therapeutics for these diseases.

Long-term outcomes with agalsidase alfa enzyme replacement therapy: Analysis using deconstructed composite events

This is a retrospective analysis of Fabry Outcome Survey data from children/adults (n = 677) receiving agalsidase alfa enzyme replacement therapy for a median of 3 years, examining cerebrovascular, cardiac, and renal morbidity endpoints separately. Cardiac events occurred at younger ages than cerebrovascular or renal events, cerebrovascular events were more frequent in females than males, and males were more likely to experience cardiac and renal events at a younger age than females.

Segment-by-segment assessment of left ventricular myocardial affection in Anderson-Fabry disease by non-enhanced T1-mapping

Background Anderson-Fabry disease (AFD) is an X-linked lysosomal enzyme disorder associated with an intracellular accumulation of sphingolipids, which shorten myocardial T1 relaxation times. Myocardial affection, however, varies between different segments. Purpose To evaluate the specific segmental distribution and degree of segmental affection in AFD patients. Material and Methods Twenty-five patients with AFD, 14 patients with hypertrophic cardiomyopathy (HCM), and 21 controls were included. A Modified Look-Locker Inversion Recovery sequence (MOLLI) was used for non-enhanced T1 mapping at 1.5 T in addition to standard cardiac imaging in 10-12 short axis views. T1 values were evaluated with a mixed model ANOVA and regression analysis to determine the best diagnostic cutoff values for T1 for each myocardial segment. Results Regression analysis showed the best diagnostic cutoff compared to controls in cardiac segments 1-4, 8-9, and 14. Mean differences between T1 for AFD versus HCM were greatest in segment 3, 4, and 9 (99 ms, 103 ms, 86 ms, respectively). Overall T1 times were 888 ± 70 ms and 903 ± 14 ms (AFD with and without LVH); 1014 ± 17 ms and 1001 ± 22 ms (HCM and controls, P < 0.05). Conclusion Myocardial segments are affected by a varying degree of T1 shortening in AFD patients. Segment-specific cutoff values allow the most specific detection and quantification of the extent of myocardial affection.

Efficacy and safety of enzyme-replacement-therapy with agalsidase alfa in 36 treatment-naïve Fabry disease patients

Background

Fabry disease (FD) is an X-linked lysosomal storage disorder resulting from the α-galactosidase A gene mutations. Enzyme-replacement-therapy (ERT) products for FD currently used include agalsidase alfa and agalsidase beta. There are many reports on efficacy and safety of ERT. However, most of the previous studies are done as a retrospective medical records analysis.

Methods

The Japan Fabry Research - 002 (JFR-002) was a prospective observational clinical study of 36 ERT-naïve FD patients (14 men and 22 women) at baseline (BL) and after initiation of ERT with agalsidase alfa 0.2 mg/kg every two weeks, a median period 62.5 months. The parameters measured included globotriaosylceramide (Gb3), globotriaosylsphingosine (Lyso-Gb3), left ventricular mass index (LVMI), brain natriuretic peptide (BNP), high-sensitivity troponin I (hs-Trop I), estimated glomerular filtration rate (eGFR), and anti-agalsidase alfa IgG antibody formation.

Results

All parameters remained steady during ERT treatment period. BNP levels in 14 patients whose BL levels were within the normal range (<19.5 pg/mL) remained within the same range, while 22 patients whose BL levels were abnormally high (≥19.5 pg/mL) gradually showed decreased levels after start of ERT. Gb3 and Lyso-Gb3 levels remarkably decreased after the initiation of ERT and remained low.

Conclusion

The JFR-002 suggests that agalsidase alfa is effective in maintaining organ function in FD patients, and that the incidence of infusion reactions related to the treatment with agalsidase alfa is low, indicating the good tolerability to this ERT.

Trial registration

The JFR-002 was retrospectively registered at Japan Medical Association Center for Clinical Trials (Registration number: JMA-IIA00291) on May 19th, 2017.

Enzyme replacement therapy for Anderson-Fabry disease: A complementary overview of a Cochrane publication through a linear regression and a pooled analysis of proportions from cohort studies

BACKGROUND

Anderson-Fabry disease (AFD) is an X-linked recessive inborn error of glycosphingolipid metabolism caused by a deficiency of alpha-galactosidase A. Renal failure, heart and cerebrovascular involvement reduce survival. A Cochrane review provided little evidence on the use of enzyme replacement therapy (ERT). We now complement this review through a linear regression and a pooled analysis of proportions from cohort studies.

OBJECTIVES

To evaluate the efficacy and safety of ERT for AFD.

MATERIALS AND METHODS

For the systematic review, a literature search was performed, from inception to March 2016, using Medline, EMBASE and LILACS. Inclusion criteria were cohort studies, patients with AFD on ERT or natural history, and at least one patient-important outcome (all-cause mortality, renal, cardiovascular or cerebrovascular events, and adverse events) reported. The pooled proportion and the confidence interval (CI) are shown for each outcome. Simple linear regressions for composite endpoints were performed.

RESULTS

77 cohort studies involving 15,305 participants proved eligible. The pooled proportions were as follows: a) for renal complications, agalsidase alfa 15.3% [95% CI 0.048, 0.303; I2 = 77.2%, p = 0.0005]; agalsidase beta 6% [95% CI 0.04, 0.07; I2 = not applicable]; and untreated patients 21.4% [95% CI 0.1522, 0.2835; I2 = 89.6%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; b) for cardiovascular complications, agalsidase alfa 28% [95% CI 0.07, 0.55; I2 = 96.7%, p<0.0001]; agalsidase beta 7% [95% CI 0.05, 0.08; I2 = not applicable]; and untreated patients 26.2% [95% CI 0.149, 0.394; I2 = 98.8%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; and c) for cerebrovascular complications, agalsidase alfa 11.1% [95% CI 0.058, 0.179; I2 = 70.5%, p = 0.0024]; agalsidase beta 3.5% [95% CI 0.024, 0.046; I2 = 0%, p = 0.4209]; and untreated patients 18.3% [95% CI 0.129, 0.245; I2 = 95% p < 0.0001]. Effect differences favored agalsidase beta over agalsidase alfa or untreated patients. A linear regression showed that Fabry patients receiving agalsidase alfa are more likely to have higher rates of composite endpoints compared to those receiving agalsidase beta.

CONCLUSIONS

Agalsidase beta is associated to a significantly lower incidence of renal, cardiovascular and cerebrovascular events than no ERT, and to a significantly lower incidence of cerebrovascular events than agalsidase alfa. In view of these results, the use of agalsidase beta for preventing major organ complications related to AFD can be recommended.

Biomarkers associated with clinical manifestations in Fabry disease patients with a late-onset cardiac variant mutation

BACKGROUND

Fabry disease is a lysosomal storage disorder with an incidence of 1:1600 for the late-onset IVS4+919G>A cardiac variant mutation in Taiwan. Signs and symptoms of this cardiac variant include left ventricular hypertrophy, mitral insufficiency and/or arrhythmias. The search for biomarkers that might predict the clinical outcomes and guide treatment options is important. We thus investigated relationships between Fabry disease biomarkers (such as globotriaosylceramide (Gb₃), globotriaosylsphingosine (lyso-Gb₃)/related analogues) and age, gender, enzyme activity, clinical manifestations and severity of the disease in these patients.

METHOD

Urine and plasma biomarkers were analyzed using tandem mass spectrometry. A large cohort of 191 adult and pediatric Fabry patients carrying the IVS4+919G>A mutation was studied. Some patients were members of the same family.

RESULTS

Our results show that the plasma lyso-Gb₃ level, and urinary analogue levels of lyso-Gb₃ at m/z (+16), (+34), and (+50) adjusted for gender and age had a positive association with the left ventricular mass index, and/or the Mainz Severity Score Index.

CONCLUSIONS

It might thus be of particular interest to monitor children with high levels of these biomarkers, as part of a longitudinal study in order to determine if the excretion profile at a young age is predictive of the outcomes of disease severity in adulthood.

Fabry disease: A fundamental genetic modifier of cardiac function

Fabry disease (FD) is an inherited X-linked metabolic storage disorder triggered by abnormalities in the GLA gene at Xq22, which leads to a deficiency in α-galactosidase A and massive accumulation of intralysosomal glycosphingolipids. Cardiac complications are very common in FD and are the main cause of late morbidity, as well as early mortality in both hemizygous men and heterozygous women. There is a need for a multidisciplinary approach to evaluation and management of FD patients as there is a wide range of presentation of FD, which varies with mutation and other organ involvement/dysfunction. An overview of common cardiac involvement and clinical characteristics in FD including: left ventricular hypertrophy (LVH), conduction abnormalities and arrhythmias, coronary artery disease and valvular infiltrative myopathy are provided in this review. Current therapeutic approaches such as enzyme replacement therapy as well as the emergence of novel therapeutic options such as gene therapy to optimize disease outcomes in FD patients will be highlighted in this paper.

Fabry Disease: A Disorder of Childhood Onset

BACKGROUND

Fabry disease, an X-linked disorder of glycosphingolipids, markedly increases the risk of systemic vasculopathy, ischemic stroke, small-fiber peripheral neuropathy, cardiac dysfunction, and chronic kidney disease.

METHODS

We performed an extensive PubMed search on the topic of Fabry disease and drew from our cumulative 43 years of experience.

RESULTS

Most of these complications are nonspecific in nature and clinically indistinguishable from similar abnormalities that occur in the context of more common disorders in the general population. This disease is caused by variants of the GLA gene, and its incidence may have been underestimated. However, one must also guard against overdiagnosis of Fabry disease and unjustified enzyme replacement therapy, because some of the gene variants are benign. Specific therapy for Fabry disease has been developed in the last few years, but its clinical effect has been modest. Novel therapeutic agents are being developed. Standard "nonspecific" medical and surgical therapy is necessary and effective in slowing deterioration or compensating for organ failure in patients with Fabry disease.

CONCLUSIONS

Fabry disease is a treatable and modifiable genetic risk factor for a myriad of clinical organ complications. Fabry disease may be frequently overlooked but on occasion overdiagnosed.

Fabry's disease: an example of cardiorenal syndrome type 5

Cardiorenal syndrome type 5 (CRS-5) includes conditions where there is a simultaneous involvement of the heart and kidney from a systemic disorder. This is a bilateral organ cross talk. Fabry's disease (FD) is a devastating progressive inborn error of metabolism with lysosomal glycosphingolipid deposition in variety of cell types, capillary endothelial cells, renal, cardiac and nerve cells. Basic effect is absent or deficient activity of lysosomal exoglycohydrolase a-galactosidase A. Renal involvement consists of proteinuria, isosthenuria, altered tubular function, presenting in second or third decade leading to azotemia and end-stage renal disease in third to fifth decade mainly due to irreversible changes to glomerular, tubular and vascular structures, especially highlighted by podocytes foot process effacement. Cardiac involvement consists of left ventricular hypertrophy, right ventricular hypertrophy, arrhythmias (sinus node and conduction system impairment), diastolic dysfunction, myocardial ischemia, infarction, transmural replacement fibrosis, congestive heart failure and cardiac death. Management of FD is based on enzymatic replacement therapy and control of renal (with anti-proteinuric agents such as angiotensin-converting enzyme inhibitors-and/or angiotensin II receptor blockers), brain (coated aspirin, clopidogrel and statin to prevent strokes) and heart complications (calcium channel blockers for ischemic cardiomyopathy, warfarin and amiodarone or cardioverter device for arrhythmias).

Fabry disease in patients with hypertrophic cardiomyopathy: a practical approach to diagnosis

This study aimed to develop a new set of screening criteria that is easily applicable and highly sensitive for the detection of patients at high risk of Fabry disease (FD) among hypertrophic cardiomyopathy (HCM) patients. We prospectively studied 273 consecutive unrelated patients who were referred to HCM clinic for unknown left ventricular hypertrophy. Among the 273 patients, we selected 65 high-risk patients who fulfilled at least one of our newly proposed screening criteria. All 273 patients were assayed for plasma α-galactosidase A (α-GAL A) activity. The new screening criteria were: (1) atypical HCM, (2) history or presence of documented arrhythmia, (3) short PR interval defined as <120 ms on electrocardiogram, and (4) symptoms of autonomic dysfunction. From this screening study, three unrelated patients (4.6%; 2 females and 1 male) were newly diagnosed with FD using α-GAL A activity and mutation analysis of the GLA gene. Using the screening method based on the newly proposed criteria, the prevalence of FD in our HCM population was 4.6% if at least one criterion was met and 18.8% if ⩾3 criteria were met. Therefore, our proposed criteria are easily applicable and highly sensitive for classifying patients at high risk of FD from HCM patients.

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.

The value of ECG parameters as markers of treatment response in Fabry cardiomyopathy

OBJECTIVE

Best treatment outcomes in Fabry disease (FD) associated cardiomyopathy can be obtained when treatment is started as early as possible. The rationale of this study was to assess the role of ECG changes for identification of cardiac involvement and patients at an earlier stage of the disease more likely deriving a benefit from enzyme replacement therapy (ERT).

METHODS

A retrospective analysis of patient data was performed from an observational, longitudinal, prospective cohort. Treatment response was defined as absence or presence of disease progression, defined as new onset or increase in left ventricular (LV) mass >10%. Demographic, clinical, ECG and echocardiographic parameters at baseline were tested for their value in determining absence or presence of disease progression under ERT at 5-year follow-up.

RESULTS

The study population consisted of a total of 38 patients (25 men, mean age 36±13 years, overall median follow-up duration 6.4±1.2 years). Patients in the progression group (14 men, 4 women) had a longer QRS duration (99±11 ms vs 84±13 ms, p<0.05 for men, 93±9 years vs 81±5 years, p<0.05 for women) and QTc interval (401±15 ms vs 372±10 ms, p<0.005 for men) and a higher amount of ECG abnormalities (86% vs 18%, p<0.005 for men and 100% vs 0%, p<0.005 for women) at the time of ERT initiation. An abnormal baseline ECG was significantly associated with disease progression (sensitivity 94.1%, specificity 88.9%, positive likelihood ratio of 8.47, p<0.005).

CONCLUSIONS

An abnormal ECG at the time of treatment initiation is significantly associated with cardiac disease progression in FD. This effect seems to be independent of age, gender or LV mass at baseline and suggests maximal treatment benefit when ERT is initiated before ECG abnormalities develop.

Electrocardiographic Changes and Arrhythmia in Fabry Disease

Fabry disease is an X-chromosome-linked lysosomal storage disease characterized by a deficient activity or, in most males, absence of the enzyme α-galactosidase A (a-Gal A) leading to systemic, primary lysosomal accumulation of globotriaosylceramide (Gb3) (1). Recent literature refers to an overall birth prevalence of 1:40,000–170,000; however, such data do not allow an estimation on an actual patient number suffering from Fabry disease (2). Multisystem morbidity commonly develops in childhood and, with progression of the disease, life-threatening complications often occur in adulthood, including renal failure, cardiovascular dysfunction, neuropathy, and stroke (3–6). Life expectancy is reduced by an average of 15 years in female patients and 20 years in male patients (7, 8). The pathognomonic Gb3 accumulation has been repeatedly observed over the past decades by many groups in vascular endothelial and smooth muscle cells, cardiomyocytes, cardiac conduction tissue, and valvular fibroblasts (3). Although incompletely described, it is likely that inflammatory and neurohormonal mechanisms are involved in subsequent cellular and vascular dysfunction, leading to tissue ischemia, hypertrophy, and fibrosis (9). Furthermore, recently published works on cardiomyocyte dysfunction and conduction tissue involvement have suggested that cardiac dysfunction may reflect increased myocardial nitric oxide production with oxidative damage of cardiomyocyte myofilaments and DNA, causing cell dysfunction and death, and accelerated conduction with prolonged refractoriness and electric instability (10, 11).

Effectiveness of agalsidase alfa enzyme replacement in Fabry disease: cardiac outcomes after 10 years' treatment

BACKGROUND

To explore long-term effects of agalsidase alfa on Fabry disease cardiomyopathy in adults.

METHODS

Retrospective analysis of prospectively collected data at a single center in Mainz, Germany, revealed that 45 adult patients (21 men, 24 women) had received agalsidase alfa for approximately 10 years. Data were extracted for cardiac and heart failure status, echocardiographic evaluations of cardiac structure and function, and renal function at treatment start and during agalsidase alfa treatment.

RESULTS

After 10 years of agalsidase alfa treatment, heart failure classification had improved by at least 1 class in 22/42 patients, and angina scores were stable or improved in 41/42 patients. During treatment, no patients without left ventricular hypertrophy (LVH) at treatment initiation developed LVH, and no patients with LVH at treatment initiation showed a decline in left ventricular mass.

CONCLUSIONS

Approximately 10 years of agalsidase alfa treatment appeared to have beneficial effects for controlling progression and improving some symptoms of Fabry-associated cardiomyopathy.

Evaluation of the efficacy and safety of three dosing regimens of agalsidase alfa enzyme replacement therapy in adults with Fabry disease

Purpose

Efficacy and safety of agalsidase alfa at 0.2 mg/kg weekly were compared with 0.2 mg/kg every other week (EOW). Exploratory analyses were performed for 0.4 mg/kg weekly.

Patients and methods

This was a 53-week, Phase III/IV, multicenter, open-label study (NCT01124643) in treatment-naïve adults (≥18 years) with Fabry disease. Inclusion criteria were left ventricular hypertrophy at baseline, defined as left ventricular mass indexed to height >50 g/m^2.7 for males and >47 g/m^2.7 for females. Primary endpoint was reduction of left ventricular mass indexed to height as assessed by echocardiography. Secondary endpoints included cardiac (peak oxygen consumption, 6-minute walk test, Minnesota Living with Heart Failure Questionnaire, New York Heart Association classification), renal (Modification of Diet in Renal Disease, estimated glomerular filtration rate), and biomarker (plasma globotriaosylceramide) assessments. Safety endpoints were adverse events and anti–agalsidase alfa antibodies.

Results

Twenty patients were randomized to 0.2 mg/kg EOW (mean age, 50.3 years; 70% male), 19 to 0.2 mg/kg weekly (51.8 years; 53% male), and 5 to 0.4 mg/kg weekly (49.4 years; 40% male). The mean change in left ventricular mass indexed to height by Week 53 in the 0.2-mg/kg EOW and weekly groups was 3.2 g/m^2.7 and 0.5 g/m^2.7, with no significant difference between groups. No clinically meaningful changes by Week 53 were found within or between the 0.2-mg/kg groups for peak oxygen consumption, 6-minute walk test, or Minnesota Living with Heart Failure Questionnaire. Two patients in each group improved by ≥1 New York Heart Association classification. No significant differences were found between 0.2 mg/kg EOW and weekly for mean change in estimated glomerular filtration rate (−1.21 mL/min/1.73 m² vs −3.32 mL/min/1.73 m²) or plasma globotriaosylceramide (−1.05 nmol/mL vs −2.13 nmol/mL), respectively. Infusion-related adverse events were experienced by 25% and 21% in the 0.2-mg/kg EOW and weekly groups. Tachycardia, fatigue, and hypotension were experienced by two or more patients overall. Anti–agalsidase alfa antibodies were detected in 11.4% of patients and neutralizing antibodies in 6.8%. Infusion-related reactions did not appear to be correlated with antibody status.

Conclusion

No efficacy or safety differences were found when the approved EOW dosage of agalsidase alfa was increased to weekly administration. Exploratory analyses for 0.4 mg/kg weekly showed similar results.

Effect and Tolerability of Agalsidase Alfa in Patients with Fabry Disease Who Were Treatment Naïve or Formerly Treated with Agalsidase Beta or Agalsidase Alfa

OBJECTIVES

In a multicenter, open-label, treatment protocol (HGT-REP-059; NCT01031173), clinical effects and tolerability of agalsidase alfa (agalα; 0.2 mg/kg every other week) were evaluated in patients with Fabry disease who were treatment naïve or switched from agalsidase beta (switch). Over 24 months, data were collected on the safety profile; renal and cardiac parameters were assessed using estimated glomerular filtration rate (eGFR), left ventricular mass index (LVMI), and midwall fractional shortening (MFS).

RESULTS

Enrolled patients included 71 switch (median [range] age, 46.6 [5-84] years; male to female [M:F], 40:31) and 29 treatment naïve (38.7 [12-74] years; M:F, 14:15). Adverse events (AEs) were consistent with the known safety profile of agalα. Two switch patients had hospitalization due to possibly/probably drug-related serious AEs (one with transient ischemic attack, one with infusion-related AEs). One switch and two treatment-naïve patients discontinued treatment because of AEs. Three patients (one each switch, treatment naïve, and previous agalα) died; no deaths were considered drug-related. There was no significant change from baseline in LVMI or MFS in either group. Similarly, eGFR remained stable; mean ± standard error annualized change in eGFR (mL/min/1.73 m(2)) was -2.40 ± 1.04 in switch and -1.68 ± 2.21 in treatment-naïve patients.

CONCLUSIONS

This is the largest cohort of patients with Fabry disease who were started on or switched to agalα in an FDA-accepted protocol during a worldwide supply shortage of agalsidase beta. Because this protocol was primarily designed to provide access to agalα, there were limitations, including not having stringent selection criteria and the lack of a placebo group.

Long-term effectiveness of agalsidase alfa enzyme replacement in Fabry disease: A Fabry Outcome Survey analysis

Outcomes from 5 years of treatment with agalsidase alfa enzyme replacement therapy (ERT) for Fabry disease in patients enrolled in the Fabry Outcome Survey (FOS) were compared with published findings for untreated patients with Fabry disease. Data were extracted from FOS, a Shire-sponsored database, for comparison with data from three published studies. Outcomes evaluated were the annualized rate of change in estimated glomerular filtration rate (eGFR) and left ventricular mass indexed to height (LVMI) as well as time to and ages at a composite morbidity endpoint and at death. FOS data were extracted for 740 treated patients who were followed for a median of ~ 5 years. Compared with no treatment, patients treated with agalsidase alfa demonstrated slower decline in renal function and slower progression of left ventricular hypertrophy. Treated male patients with baseline eGFR < 60 mL/min/1.73 m² had a mean (standard error of the mean [SEM]) annualized change in eGFR of − 2.86 (0.53) mL/min/1.73 m²/y compared with − 6.8 (1.5) in the published untreated cohort. The mean (SEM) rate of LVMI increase with treatment was 0.33 (0.10) g/m^2.7/y in males and 0.48 (0.09) in females, compared with 4.07 (1.03) in untreated males and 2.31 (0.81) in untreated females. Morbidity occurred later in treated patients, with ~ 16% risk of a composite morbidity event (26% in males) after 24 months with ERT versus ~ 45% without treatment, with first events and deaths also occurring at older ages in patients administered ERT (e.g., estimated median survival in treated males was 77.5 years versus 60 years in untreated males). Findings from these retrospective comparisons of observational data and published literature support the long-term benefits of ERT with agalsidase alfa for Fabry disease in slowing the progression of renal impairment and cardiomyopathy. Treatment also appeared to delay the onset of morbidity and mortality. Interpretation of these findings should take into account that they are based on retrospective comparisons with previously published data.

Agalsidase alfa in pediatric patients with Fabry disease: a 6.5-year open-label follow-up study

Background

Signs and symptoms of the X-linked disorder, Fabry disease (FD), can occur early during childhood with heterogeneous clinical manifestations including potential cardiac and renal dysfunction. Several studies support the efficacy of the enzyme replacement therapy (ERT) agalsidase alfa, in adults with FD, though published data on the long-term safety and efficacy of agalsidase alfa in children are limited. As early treatment with ERT has the potential to reduce complications arising from disease progression, children in particular could benefit. The objective of this study was to evaluate the safety and efficacy of long-term agalsidase alfa ERT in children with FD.

Methods

TKT029 was a 6.5-year open-label, multicenter, extension study of children who completed TKT023 (26-week, open-label, every-other-week, intravenous 0.2 mg/kg agalsidase alfa). TKT029 was divided into two phases (before and after an agalsidase alfa manufacturing process change); only patients who participated in both phases were included in the analysis. Primary endpoints included safety, tolerability, and heart rate variability (HRV). Additional efficacy parameters included left ventricular mass index (LVMI), estimated glomerular filtration rate (eGFR), and plasma/urine globotriaosylceramide (Gb₃).

Results

Eleven patients participated (phase 1 baseline median [range] age: 10.8 [8.6–17.3] years; 10 [90.9%] males). During TKT029 (6.5 years), all patients experienced ≥1 treatment-emergent adverse event (AE); eight patients had ≥1 possibly/probably drug-related AE. Six patients experienced infusion-related AEs, but none discontinued due to AEs. Eight serious AEs arose (two patients); none were deemed drug-related. No deaths occurred. Three patients developed anti-agalsidase alfa antibodies, with IgG antibodies in one patient that were agalsidase alfa neutralizing, but without apparent clinical impact. Renal (eGFR) endpoints remained generally in normal range. Cardiac endpoints remained stable within normal range for LVMI and a trend towards improved HRV, although some patients experienced a reduction in heart rate. Plasma and urinary Gb₃ reductions were maintained.

Conclusions

TKT029 represents the longest assessment of ERT in children with FD in a clinical trial setting. Overall, agalsidase alfa was well tolerated and demonstrated a stabilizing clinical effect. Agalsidase alfa may be a useful clinical therapeutic option for long-term treatment initiated during childhood in patients with FD.

Trial registration

http://ClinicalTrials.gov identifier NCT00084084.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-014-0169-6) contains supplementary material, which is available to authorized users.

Effective clearance of GL-3 in a human iPSC-derived cardiomyocyte model of Fabry disease

Fabry disease, a rare X-linked α-galactosidase A deficiency, causes progressive lysosomal accumulation of globotriaosylceramide (GL-3) in a variety of cell types. As the disease progresses, renal failure, left ventricular hypertrophy, and strokes may occur. Enzyme replacement therapy (ERT), with recombinant α-galactosidase A, is currently available for use to reduce GL-3 deposits. However, although it improves cardiac function and decreases left ventricular mass, GL-3 clearance upon ERT has been demonstrated in cardiac capillary endothelium but not in cardiomyocytes of patients. Relevant models are needed to understand the pathogenesis of cardiac disease and explore new therapeutic approaches. We generated induced pluripotent stem cells (iPSC) from Fabry patients and differentiated them into cardiomyocytes. In these cells, GL-3 accumulates in the lysosomes over time, resulting in phenotypic changes similar to those found in cardiac tissue from Fabry patients. Using this human in vitro model, we demonstrated that substrate reduction therapy via glucosylceramide synthase inhibition was able to prevent accumulation and to clear lysosomal GL-3 in cardiomyocytes. This new in vitro model recapitulates essential features of cardiomyocytes from patients with Fabry disease and therefore provides a useful and relevant tool for further investigations of new therapy.

Endomyocardial biopsies in patients with left ventricular hypertrophy and a common Chinese later-onset Fabry mutation (IVS4 + 919G > A)

BACKGROUND

In Taiwan, DNA-based newborn screening showed a surprisingly high incidence of a cardiac Fabry mutation (IVS4 + 919G > A). The prevalence of this mutation is too high to be believed that it is a real pathogenic mutation. The purpose of this study is to identify the cardiac pathologic characteristics in patients with left ventricular hypertrophy and this mutation

METHODS AND RESULTS

Endomyocardial biopsies were obtained in 22 patients (Median age: 61, males: 17; females: 5) with left ventricular hypertrophy and the IVS4 + 919G > A mutation; five patients had not received enzyme replacement therapy (ERT) before biopsy, while the other 17 patients had received ERT from 8 months to 51 months. Except for three patients who had received ERT for more than 3 years, all other patients showed significant pathological change and globotriaosylceramide (Gb3) accumulation in their cardiomyocytes. In contrast to classical Fabry patients, no Gb3 accumulation was found in the capillary endothelial cells of any of our patients. Fourteen patients (63.6%) were found to have myofibrillolysis.

CONCLUSIONS

All of the untreated and most of the treated IVS4 + 919G > A patients showed typical pathological changes of Fabry disease in their cardiomyocytes. No endothelial accumulation of Gb3 was found, which is similar to the findings of several previous reports regarding later-onset Fabry disease. This result highly suggests that the IVS4 + 919G > A is a real pathogenic later-onset Fabry mutation.

Natural course of Fabry disease and the effectiveness of enzyme replacement therapy: a systematic review and meta-analysis: effectiveness of ERT in different disease stages

OBJECTIVE

Current available evidence on long-term effectiveness of enzyme replacement therapy (ERT) for Fabry disease is limited. More insight is needed whether ERT effectiveness differs in patients with and without baseline end-organ damage.

DESIGN

Through a systematic review, untreated and ERT treated males and females with Fabry disease were compared for main clinical outcomes: renal function, left ventricular mass (LVmass), cerebral white matter lesions (WMLs) and end-organ complications. Through a meta-analysis ERT effectiveness was estimated in different disease stages.

DATA EXTRACTION

Two reviewers assessed quality of the included studies according to guidelines for prognosis research. Data were synthesized using a random effects meta-analysis.

RESULTS

Thirty-one studies were systematically reviewed while six studies were included in the meta-analysis. In patients with a GFR > 60 ml/min/1.73 m(2), decline of renal function was similar for treated and untreated patients. Only ERT treated males with a GFR < 60 ml/min/1.73 m(2) had a slower rate of decline in renal function, possibly attributable to anti-proteinuric therapy. Regardless of left ventricular hypertrophy (LVH) at baseline, LVmass remained stable or increased in males despite ERT, however at a slower rate compared to untreated male patients. In ERT treated females with LVH LVmass decreased, and remained stable in females without LVH. WMLs can not be prevented by ERT. Stroke, cardiac and end-stage renal complications develop, though the incidence of new complications seems to be reduced during ERT.

CONCLUSION

ERT is effective in reducing LVH, but has a limited effect on renal function. Improved treatment options are needed for Fabry disease.

Prevalence of Fabry disease in male patients with unexplained left ventricular hypertrophy in primary cardiology practice: prospective Fabry cardiomyopathy screening study (FACSS)

BACKGROUND

A number of studies have already investigated the prevalence of Fabry disease (FD) in adult patients with unexplained left ventricular hypertrophy (LVH) with rates varying from 0 % up to 12 % reflecting referral and gender bias as well as differences in diagnostic methodology. We aimed to perform a prospective screening study evaluating the prevalence of FD in male patients older than 30 years with strictly defined unexplained LVH followed by general cardiologists.

METHODS

A predefined number of 100 men with unexplained LVH, defined as maximal wall thickness ≥ 13 mm, were identified during an echocardiographic examination in primary cardiology practice and screened by assessing α-galactosidase A activity in dried blood spots (DBS) or in plasma.

RESULTS

Four men (52 ± 4 years, maximal LV wall thickness 18 ± 3 mm) were diagnosed with FD confirmed by enzyme analysis in leukocytes as well as by genetic analysis. Mild extracardiac manifestations of FD were present in two of them.

CONCLUSIONS

The prevalence of FD in our cohort of male patients followed in primary cardiology practice with strictly defined otherwise unexplained LVH was 4 %. We recommend systematic screening for FD in all men older than 30 years with LVH of unknown etiology even in the absence of obvious extracardiac manifestations of FD.

Analysis of left ventricular mass in untreated men and in men treated with agalsidase-β: data from the Fabry Registry

PURPOSE

The aim of this study was to evaluate the progression of left ventricular hypertrophy in untreated men with Fabry disease and to assess the effects of agalsidase-β (recombinant human α-galactosidase A) on left ventricular hypertrophy.

METHODS

Longitudinal Fabry Registry data were analyzed from 115 men treated with agalsidase-β (1 mg/kg/2 weeks) and 48 untreated men. Measurements included baseline left-ventricular mass and at least one additional left-ventricular mass assessment over ≥ 2 years. Patients were grouped into quartiles, based on left-ventricular mass slopes. Multivariate logistic regression analyses identified factors associated with left ventricular hypertrophy progression.

RESULTS

For men in whom treatment was initiated at the age of 18 to <30 years, mean left ventricular mass slope was -3.6 g/year (n = 31) compared with +9.5 g/year in untreated men of that age (n = 15) (P < 0.0001). Untreated men had a 3.4-fold higher risk of having faster increases in left-ventricular mass compared with treated men (odds ratio: 3.43; 95% confidence interval: 1.05-11.22; P = 0.0415). A baseline age of ≥ 40 years was also associated with left--ventricular hypertrophy progression (odds ratio: 5.03; 95% confidence interval: 1.03-24.49; P = 0.0457) compared with men younger than 30 years.

CONCLUSION

Agalsidase-β treatment for ≥2 years may improve or stabilize left-ventricular mass in men with Fabry disease. Further investigations may determine whether early intervention and stabilization of LVM are correlated with clinical outcomes.

Early cardiac changes in children with anderson-fabry disease

OBJECTIVE

Limited evidence is available about the early cardiac manifestation of Fabry disease (FD) in children. We aimed to evaluate cardiac involvement in children with FD by analysing serial structural and electrocardiographic changes.

METHODS

The data were acquired from 22 children with FD [11 males; median age 9.8 (ranging 2.5-16) years]. Seven patients (5 males) were on enzyme replacement therapy (ERT) with Agalasidase alpha. Echocardiography, ECG and 24-h ECG monitoring recordings were acquired during routine annual clinical controls. ECG data were compared to a group of age-and gender-matched controls.

RESULTS

At baseline, ECG and ECHO parameters of left ventricular mass were similar in both males and females. Three boys (all were on ERT) developed left ventricular hypertrophy (LVH) during two-year follow-up. The progression to LVH was accompanied by the appearance of frequent ventricular premature beats in two cases and supraventricular premature beats (SPBs) with T wave inversion in one case. T wave inversion and SPBs were detected in two younger relatives of a patient with LVH, in the absence of detectable LVH. Seven out of 22 patients had T wave abnormalities. Five of them were males (p = 0.03) all carrying the N215S mutation (p = 0.03). At baseline, median PR intervals were prolonged in FD subjects compared to controls [143 (122-177) vs. 122 (82-165) ms; p < 0.0001].

CONCLUSIONS

Cardiac complications of FD become apparent in childhood as subtle changes with slow but detectable progression over time, with males more frequently affected than females. Progression of LVH was apparent in three children despite ERT.

Cardiac disease in children and young adults with various lysosomal storage diseases: Comparison of echocardiographic and ECG changes among clinical groups

BACKGROUND

Lysosomal storage disease (LSD) is a rare inherited disease group. Consecutively there are few data on cardiac changes in mucopolysaccharidosis (MPS), Anderson Fabry disease (AFD), and other LSD (oLSD) including Pompe disease (PD) and Danon disease (DD), I-cell disease ICD and mucolipidosis III (ML III).

METHODS

Between 1994 and 2011, we identified 39 patients with LSD: 25 with MPS, 8 with AFD, and 6 with oLSD including PD (1), ML III (2), DD (1), and ICD (2) at our institution fulfilling the inclusion criteria of at least one echocardiogram and ECG.

RESULTS

Median age was 11.4 years (range: 2-27), 22 were females (56%). Normal echocardiograms were present in 12 patients (31%): 4 with MPS (16%), 7 AFD (88%), and 1 oLSD (17%). Valvular heart disease was present in 23 patients (59%) occurring more often in MPS (76%) and oLSD (67%) than in AFD (0%) (p < 0.001). The most common ECG abnormality was a short PR interval in 10 of 35 patients (29%) occurring in all LSD groups. Median follow-up was 5.8 (0.2-22.2) years showing diminished 5-year survival compared to an age-matched group. However, no patient died due to a cardiac cause and no cardiovascular intervention was necessary.

CONCLUSION

Echocardiographically detectable cardiovascular involvement in children with LSD is mostly confined to MPS and oLSD. Valve thickening in echo and a short PR interval in the ECG are the most frequent abnormalities. Routine repeat assessment is recommended in LSD. However, significant cardiac disease necessitating cardiac intervention is rare during a short follow-up.

Enzyme replacement therapy in patients with Fabry disease: state of the art and review of the literature

Anderson-Fabry disease is an X-linked lysosomal storage disorder resulting from the deficiency of the hydrolytic enzyme alpha galactosidase A, with consequent accumulation of globotrioasoyl ceramide in cells and tissues of the body, resulting in a multi-system pathology including end organ failure. In the classical phenotype, cardiac failure, renal failure and stroke result in a reduced median life expectancy. The current causal treatment for Fabry disease is the enzyme replacement therapy (ERT): two different products, Replagal (agalsidase alfa) and Fabrazyme (agalsidase beta), have been commercially available in Europe for almost 10 years and they are both indicated for long-term treatment. In fact, clinical trials, observational studies and registry data have provided many evidences for safety and efficacy of ERT in improving symptoms of pain, gastrointestinal disturbances, hypohidrosis, left ventricular mass index, glomerular filtration rate and quality of life. Few data are available on comparison of the two treatments and on the clinical course of the disease. This article reviews the published evidence for clinical efficacy of the two available enzyme preparations.

Effects of switching from agalsidase Beta to agalsidase alfa in 10 patients with anderson-fabry disease

Anderson-Fabry disease (AFD) is a multiorgan X-linked lysosomal storage disease that particularly affects the heart, kidneys, and cerebrovascular system. Current treatment is enzyme replacement therapy (ERT) with agalsidase beta (Fabrazyme(®), Genzyme Corporation, Cambridge, MA, USA) or agalsidase alfa (Replagal(®), Shire Human Genetic Therapies AB, Lund, Sweden). It was recommended that patients switch to agalsidase alfa due to a manufacturing shortage of agalsidase beta beginning in June 2009. This study assessed the effect of switching to agalsidase alfa on clinical outcomes in patients with AFD previously treated with agalsidase beta. Ten patients (seven male, three female) with genetically confirmed AFD and at least 48 months' continuous data collected during treatment with agalsidase beta 1 mg/kg every other week were switched to agalsidase alfa 0.2 mg/kg every other week for at least 20 months, with prospective clinical evaluations every 6 months. Pre-switch data was collected retrospectively from patient charts. Cardiac functional parameters were assessed using magnetic resonance imaging. Results showed that renal function was normal (estimated glomerular filtration rate ≥90 mL/min/1.73 m(2)) in 8 of 10 patients prior to agalsidase alfa and generally remained stable after the switch. Cardiac mass decreased significantly (p < 0.05 vs pre-ERT) after agalsidase beta and remained unchanged after switching to agalsidase alfa. Symptoms of pain and health status scores did not deteriorate during agalsidase alfa therapy. Adverse events were mostly mild and infusion related. In conclusion, switching to agalsidase alfa was relatively well tolerated and associated with stable clinical status and preserved renal and cardiac function.

Increased arterial stiffness is associated with high cardiovascular mortality in male Fabry patients

Cardiovascular survival in a cohort of 33 male Fabry patients followed for a median of 7.3 years at a single centre was most strongly associated in a Cox proportional hazard regression model with age and elevated arterial stiffness at baseline. Seven patients died of cardiovascular causes. The presence of cardiomyopathy and renal involvement (either clinical nephropathy or CKD stage >1) were also negatively associated with survival when analysed as single factors. In this small study, presence of hypertension and hypercholesterolemia at baseline did not significantly predict cardiovascular death. The significant effect of elevated arterial stiffness, especially in a small cohort, argues for its clinical utility in individual patient risk assessment and for further intervention studies focusing on therapeutic reduction.

Prevalence of Fabry disease in a predominantly hypertensive population with left ventricular hypertrophy

BACKGROUND

Patients with Fabry disease (FD) develop progressive left ventricular hypertrophy (LVH). In screening studies in patients with LVH, the prevalence of FD ranges from 0 to 12%. This variability is attributable to different factors like diverging inclusion and exclusion criteria, the evaluation of selected populations and suboptimal screening methods. In this study, we aimed to determine the prevalence of FD in an unselected population of everyday clinical practice presenting LVH, defined as a maximal end-diastolic septal or posterior wall thickness ≥ 13 mm, without exclusion of patients with arterial hypertension or valvular pathology, and using optimal screening methods.

METHODS

In adult males, a two-tier approach was used; α-Galactosidase A (aGAL A) activity was measured using a dried bloodspot test (DBS) and diagnosis was confirmed by mutation analysis of the GLA gene. In females, mutation analysis was the primary screening tool.

RESULTS

362 men and 178 women were screened. Six patients were diagnosed with a genetic sequence alteration of the GLA gene. One man had a novel mutation, GLA p.Ala5Glu (c.44C>A), presenting as classical FD. Another man and three women had the previously described GLA p.Ala143Thr (c.427G>A) mutation, which generally presents as an attenuated phenotype. One woman had a novel sequence alteration c.639+6A>C, which appeared to be a polymorphism. All true Fabry patients had arterial hypertension (AHT), and one had hypertrophic obstructive cardiomyopathy (HOCM).

CONCLUSIONS

In a group of unselected patients with LVH, we found a prevalence of Fabry disease of 0.9%. AHT or type of hypertrophy should not be an exclusion criterion for screening for FD.

Effects of enzyme replacement therapy in adult patients with Fabry disease on cardiac structure and function: a retrospective cohort study of the Fabry Munster Study (FaMuS) data

OBJECTIVE

Fabry disease (FD) is an X-linked inborn error of glycosphingolipid catabolism caused by deficient lysosomal α-galactosidase A activity. Progressive accumulation of globotriaosylceramide and related glycosphingolipids in vascular endothelial lysosomes of the heart, kidneys and brain is responsible for the main disease manifestations. The aim of our study was to assess short-term and long-term effects of enzyme replacement therapy (ERT) on cardiac mass and function.

DESIGN

Retrospective cohort study.

SETTING

Hospital outpatient clinic.

PARTICIPANTS

40 FD patients (21 men, 19 women) receiving agalsidase β-ERT.

OUTCOME MEASURES

The focus at baseline and follow-up examinations was on structural, functional (Doppler-echocardiography) as well as electrical changes (ECG) and blood pressure.

RESULTS

In the Early Group, systolic and diastolic blood pressures significantly decreased. Left-ventricular (LV) also decreased; however, wall thickness and LV mass index showed no further increase. VE as an indicator for diastolic function significantly improved (64±21 vs 75±27 cm/s, p=0.038). There were no significant changes of ECG parameters. There were few relevant changes in the Late Group, albeit systolic blood pressure significantly decreased and QRS duration significantly increased. In conclusion, echocardiographic left-ventricular mass index, interventricular septum thickness, left-ventricular posterior wall, left-ventricular end-diastolic dimension) and diastolic function parameters are valuable for follow-up and guidance of therapy.

CONCLUSIONS

The primary positive impact of ERT appears to be an early effect after the start of therapy, and early initiation of ERT should be recommended.