The effectiveness of long-term agalsidase alfa therapy in the treatment of Fabry nephropathy

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.

Aseptic meningitis and Fabry disease

OBJECTIVE

Fabry disease is caused by enzymatic defects in alpha-galactosidase A that leads to the accumulation of glycosphingolipids throughout the body, resulting in a multisystemic disorder. The most common neurological manifestations are neuropathic pain, autonomic nervous system dysfunction and strokes, but some rarer neurological manifestations exist. Among these, aseptic meningitis is a possible complication. Our objectives were to measure the prevalence of this complication in a cohort of patients with Fabry disease, and to describe its clinical features.

METHODS

We conducted a retrospective review of Fabry disease patients followed at our tertiary referral center between 1995 and September 2023 with at least one episode of meningitis, and performed a systematic review to identify similar published cases.

RESULTS

Four patients out of 107 (3.7%) had at least one episode of aseptic meningitis. Our systematic review identified 25 other observations. The median age of these 29 patients was 29.0 years, the median cerebrospinal fluid leukocyte count was 24 cells/mm3 with a predominance of lymphocytes in 64.7% of cases. In 82.8% of the patients, the diagnosis of Fabry disease was unknown before the meningitis. Large artery stenosis was present in 17.2% of patients and 57.1% of patients had a recent stroke concomitant with the meningitis. Several differential diagnoses were evoked, such as multiple sclerosis or central nervous system vasculitis.

INTERPRETATION

Our study suggests that Fabry disease should be considered as a cause of aseptic meningitis. The pathophysiological mechanisms underlying meningeal inflammation remain largely unknown but may reflect the dysregulation of pro-inflammatory signaling pathways.

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.

The Importance of Early Treatment of Inherited Neuromuscular Conditions

There has been tremendous progress in treatment of neuromuscular diseases over the last 20 years, which has transformed the natural history of these severely debilitating conditions. Although the factors that determine the response to therapy are many and in some instance remain to be fully elucidated, early treatment clearly has a major impact on patient outcomes across a number of inherited neuromuscular conditions. To improve patient care and outcomes, clinicians should be aware of neuromuscular conditions that require prompt treatment initiation. This review describes data that underscore the importance of early treatment of children with inherited neuromuscular conditions with an emphasis on data resulting from newborn screening efforts.

Fabry Disease in Women: Genetic Basis, Available Biomarkers, and Clinical Manifestations

Fabry Disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene on the X chromosome, leading to a deficiency in α-galactosidase A (AGAL) enzyme activity. This leads to the accumulation of glycosphingolipids, primarily globotriaosylceramide (Gb3), in vital organs such as the kidneys, heart, and nervous system. While FD was initially considered predominantly affecting males, recent studies have uncovered that heterozygous Fabry women, carrying a single mutated GLA gene, can manifest a wide array of clinical symptoms, challenging the notion of asymptomatic carriers. The mechanisms underlying the diverse clinical manifestations in females remain not fully understood due to X-chromosome inactivation (XCI). XCI also known as "lyonization", involves the random inactivation of one of the two X chromosomes. This process is considered a potential factor influencing phenotypic variation. This review delves into the complex landscape of FD in women, discussing its genetic basis, the available biomarkers, clinical manifestations, and the potential impact of XCI on disease severity. Additionally, it highlights the challenges faced by heterozygous Fabry women, both in terms of their disease burden and interactions with healthcare professionals. Current treatment options, including enzyme replacement therapy, are discussed, along with the need for healthcare providers to be well-informed about FD in women, ultimately contributing to improved patient care and quality of life.

Prevalence of Kidney and Urinary Tract Complications in Fabry Disease from 2000 to 2020: A Global Cohort Study Including 10,637 Patients

BACKGROUND/AIM

Fabry disease, an X-linked lysosomal storage disorder, causes progressive globotriaosylceramide accumulation in cells throughout the body. Characteristic multiorgan manifestations include renal dysfunction (Fabry nephropathy) and associated urinary tract complications. Enzyme replacement therapy (ERT) has been available since 2001, but contemporary real-world data are lacking regarding Fabry nephropathy risks and treatment outcomes.

PATIENTS AND METHODS

This retrospective cohort study analyzed electronic medical records data for 10,637 Fabry disease patients from the TriNetX research database. Kidney and urinary tract outcomes were evaluated over two decades, 2000-2010 and 2011-2020. Outcomes assessed included chronic kidney disease (CKD), urinary tract infections, urinary incontinence, obstruction, renal insufficiency, and end-stage renal disease (ESRD).

RESULTS

The prevalence of stage 4-5 CKD nearly doubled between 2000-2010 and 2011-2020, while ESRD prevalence rose over 4-fold. Incidence rates showed similar marked elevations across renal and urologic complications. Females and Black patients experienced disproportionate escalations in kidney and urinary tract morbidity.

CONCLUSION

This large cohort study revealed significantly increased Fabry nephropathy and associated urologic complications over the past two decades, contradicting expectations of reduced morbidity with ERT availability. The findings highlight needs to optimize screening, treatment strategies, monitoring practices, and address disparities to curb rising disease burden and improve patient outcomes.

Treatment of Fabry Nephropathy: A Literature Review

Fabry disease is an X-linked inherited lysosomal storage disorder with a deficiency of α-galactosidase A activity, which results in the intracellular accumulation of globotriaosylceramide (Gb3) and related glycosphingolipids in various organs. Fabry nephropathy is one of the major complications of Fabry disease, and kidney damage is often related to cardiovascular disease and mortality. The treatment of Fabry nephropathy thus helps prolong life expectancy. Two treatment options for Fabry nephropathy and cardiopathy are now commercially available: enzyme replacement therapy (agalsidase α agalsidase β, and a biosimilar of agalsidase β) and pharmacological chaperone therapy (migalastat). In this review, we summarize the efficacy of these treatment options for Fabry nephropathy with respect to renal function, proteinuria, and renal pathological findings. We also describe the importance of adjunctive therapy for Fabry nephropathy.

Vitamin C Urinary Loss in Fabry Disease: Clinical and Genomic Characteristics of Vitamin C Renal Leak

BACKGROUND

Reduced plasma vitamin C concentrations in chronic diseases may result from abnormal urinary excretion of vitamin C: a renal leak. We hypothesized that vitamin C renal leak may be associated with disease-mediated renal dysregulation, resulting in aberrant vitamin C renal reabsorption and increased urinary loss.

OBJECTIVES

We investigated the prevalence, clinical characteristics, and genomic associations of vitamin C renal leak in Fabry disease, an X-linked lysosomal disease associated with renal tubular dysfunction and low plasma vitamin C concentrations.

METHODS

We conducted a non-randomized cross-sectional cohort study of men aged 24-42 y, with Fabry disease (n = 34) and controls without acute or chronic disease (n = 33). To match anticipated plasma vitamin C concentrations, controls were placed on a low-vitamin C diet 3 wk before inpatient admission. To determine the primary outcome of vitamin C renal leak prevalence, subjects were fasted overnight, and matched urine and fasting plasma vitamin C measurements were obtained the following morning. Vitamin C renal leak was defined as presence of urinary vitamin C at plasma concentrations below 38 μM. Exploratory outcomes assessed the association between renal leak and clinical parameters, and genomic associations with renal leak using single nucleotide polymorphisms (SNPs) in the vitamin C transporter SLC23A1.

RESULTS

Compared with controls, the Fabry cohort had 16-fold higher odds of renal leak (6% vs. 52%; OR: 16; 95% CI: 3.30, 162; P < 0.001). Renal leak was associated with higher protein creatinine ratio (P < 0.01) and lower hemoglobin (P = 0.002), but not estimated glomerular filtration rate (P = 0.54). Renal leak, but not plasma vitamin C, was associated with a nonsynonymous single nucleotide polymorphism in vitamin C transporter SLC23A1 (OR: 15; 95% CI: 1.6, 777; P = 0.01).

CONCLUSIONS

Increased prevalence of renal leak in adult men with Fabry disease may result from dysregulated vitamin C renal physiology and is associated with abnormal clinical outcomes and genomic variation.

Fabry Disease: Current and Novel Therapeutic Strategies. A Narrative Review

BACKGROUND

Fabry disease (FD) is an inherited lysosomal storage disorder, leading to multisystemic manifestations and causing significant morbidity and mortality.

OBJECTIVE

The aim of this narrative review is to present the current and novel therapeutic strategies in FD, including symptomatic and specific treatment options.

METHODS

A systematic literature search was conducted to identify relevant studies, including completed and ongoing randomized-controlled clinical trials (RCTs), prospective or retrospective cohort studies, case series and case reports that provided clinical data regarding FD treatment.

RESULTS

A multidisciplinary symptomatic treatment is recommended for FD patients, personalized according to disease manifestations and their severity. During the last two decades, FD-specific treatments, including two enzyme-replacement-therapies (agalsidase alfa and agalsidase beta) and chaperone treatment with migalastat have been approved for use and allowed for symptoms' stabilization or even disease burden reduction. More therapeutic agents are currently under investigation. Substrate reduction therapies, including lucerastat and venglustat, have shown promising results in RCTs and may be used either as monotherapy or as complementary therapy to established enzymereplacement- therapies. More stable enzyme-replacement-therapy molecules that are associated with less adverse events and lower likelihood of neutralizing antibodies formation have also been developed. Ex-vivo and in-vivo gene therapy is being tested in animal models and pilot human clinical trials, with preliminary results showing a favorable safety and efficacy profile.

CONCLUSION

The therapeutic landscape in FD appears to be actively expanding with more treatment options expected to become available in the near future, allowing for a more personalized approach in FD patients.

Twenty years of the Fabry Outcome Survey (FOS): insights, achievements, and lessons learned from a global patient registry

Background

Patient registries provide long-term, real-world evidence that aids the understanding of the natural history and progression of disease, and the effects of treatment on large patient populations with rare diseases. The year 2021 marks the 20th anniversary of the Fabry Outcome Survey (FOS), an international, multicenter, observational registry (NCT03289065). The primary aims of FOS are to broaden the understanding of Fabry disease (FD), an X-linked lysosomal storage disorder, and to improve the clinical management of affected patients. Here, we review the history of FOS and the analyses and publications disseminated from the registry, and we discuss the contributions FOS studies have made in understanding FD.

Results

FOS was initiated in April 2001 and, as of January 2021, 4484 patients with a confirmed diagnosis and patient informed consent have been enrolled from 144 centers across 26 countries. Data from FOS have been published in nearly 60 manuscripts on a wide variety of topics relevant to FD. Analyses of FOS data have investigated the long-term effectiveness and safety of enzyme replacement therapy (ERT) with agalsidase alfa and its effects on morbidity and mortality, as well as the benefits of prompt and early treatment with agalsidase alfa on the progression of cardiomyopathy and the decline in renal function associated with FD. Based on analyses of FOS data, ERT with agalsidase alfa has also been shown to improve additional signs and symptoms of FD experienced by patients. FOS data analyses have provided a better understanding of the natural history of FD and the specific populations of women, children, and the elderly, and have provided practical tools for the study of FD. FOS has also provided methodology and criteria for assessing disease severity which contributed to the continuous development of medical practice in FD and has largely improved our understanding of the challenges and needs of long-term data collection in rare diseases, aiding in future rare disease real-world evidence studies.

Conclusion

FOS over the last 20 years has substantially increased the scientific knowledge around improved patient management of FD and continues to expand our understanding of this rare disease.

Fabry disease with acute myocardial infarction, left ventricular thrombosis, and pericardial effusion: A case report

RATIONALE

Fabry disease (FD) is a rare, X-linked lysosomal deposition disease characterized by multi-system symptoms. The accumulation of globotriaosylceramide in various organs, such as the kidneys and heart, as well as the nervous system, has been speculated to be the mechanism involved in tissue damage, including vascular impairment with thrombotic events.

PATIENT CONCERNS

Here, we describe a 72-year-old male patient diagnosed with FD, who first presented with acute myocardial infarction, left ventricular thrombosis, and pericardial effusion, accompanied by cardiac hypertrophy.

DIAGNOSES

A physical examination showed that he was hemodynamically stable and an electrocardiogram showed ventricular tachycardia (Fig. 1A). The single obvious abnormality was an ST segment depression with a preterminal negative T wave in leads I and aVL (Fig. 1B). Coronary angiography revealed regular findings (Fig. 2). Echocardiogram conducted at our hospital revealed hypertrophy, ejection fraction 40%, pericardial effusion (Fig. 3). Speckle tracking two-dimensional echocardiography strain analysis technology confirmed left ventricular thrombosis, and also revealed decreased movement of the inferior and posterior walls, the basal segment of the posterior wall was locally fibrotic (Fig. 4A and B). Further, myocardial contrast echocardiography confirmed left ventricular thrombosis (Fig. 4C). Cardiovascular magnetic resonance imaging indicated biventricular uneven hypertrophy, which was considered metabolic cardiomyopathy, with diffuse fibrosis of biventricular walls, apical thrombosis, and ischemic cardiomyopathy in the basal segment of the left ventricular lateral wall and left ventricular anterior wall (Fig. 5). Serum alpha-galactosidase concentration was 0.7 nmol/h/mgPr (normal range, 29.0-64.4 nmol/h/mgPr). Subsequent genetic testing revealed that he was hemizygous for a previously reported missense mutation (c.902G>A) inexon 6 of the GLA gene,[1] which induce p.R301Q (p.Arg301Gln), confirming a diagnosis of FD (Fig. 6).

INTERVENTIONS

Orally administered drugs included rivaroxaban, sacubitril valsartan, beta blockers, dapagliflozin, and mineralocorticoid receptor antagonist. Cardiac resynchronization therapy with an implanted defibrillator was implemented to prevent sudden death.

OUTCOMES

At present, he is still in follow-up and there have been no adverse events.

CONCLUSION

Our case suggests that clinicians should consider the possibility of FD in patients with acute myocardial infarction and cardiomyopathy. A detailed analysis of subtle historical clues would help promote earlier diagnosis of FD.

Fabry nephropathy before and after enzyme replacement therapy: important role of renal biopsy in patients with Fabry disease

Background

In Fabry disease, the presence of globotriaosylceramide (GL3) deposits in various kidney cells leads to progressive renal dysfunction. However, kidney biopsy studies in patients with Fabry disease are limited. In the present study, the pathologic findings of patients with Fabry nephropathy receiving enzyme replacement therapy (ERT) and untreated patients without albuminuria were investigated.

Methods

The present study included 15 patients with Fabry disease who underwent renal biopsy while receiving ERT (group 1: n = 9, age 19–58 years, two males and seven females) or before ERT initiation (group 2: n = 6, age 11–66 years, one male and five females). All patients in group 2 were normoalbuminuric.

Results

Group 1 showed improved clinical symptoms, such as acroparesthesia. The ERT duration was 1.2 to 8 years and seven of the nine patients showed GL3 deposits in various kidney cells and segmental foot process effacement (FPE) of podocytes. GL3 deposits and FPE were not observed in the two remaining patients in group 1. Group 2 showed segmental FPE and podocyte GL3 deposits. Most patients in group 2 also showed GL3 deposits in the mesangium, endothelium, or tubular epithelium.

Conclusion

The study results showed that segmental FPE and GL3 deposits can persist in Fabry nephropathy despite ERT. In addition, segmental FPE and GL3 deposits were observed in various kidney cells in normoalbuminuric patients with Fabry disease. These findings indicated that kidney biopsies at baseline and follow-up evaluation of Fabry nephropathy are essential for timely ERT initiation and ERT response assessment.

The Safety of Agalsidase Alfa Enzyme Replacement Therapy in Canadian Patients with Fabry Disease Following Implementation of a Bioreactor Process

Background and Objective

Fabry disease, an X-linked lysosomal storage disorder characterized by absent or reduced alpha-galactosidase activity, is a lifelong disease that impairs patients’ quality of life. Patients with Fabry disease have a considerably shortened lifespan, with mortality being mainly due to renal failure, cardiovascular disease, or cerebrovascular disease. Enzyme replacement therapy with agalsidase alfa has been shown to attenuate the renal, cardiovascular, and neuropathic disease progression associated with Fabry disease. The objective of this study was to investigate the safety of a new animal component-free version of agalsidase alfa.

Methods

A phase III/IV, open-label, single-arm, multicenter safety study was conducted in Canadian patients with Fabry disease between August 2011 and September 2017 as a regulatory requirement to assess the safety of agalsidase alfa produced using an animal component-free bioreactor process. Eligible patients had a documented diagnosis of Fabry disease and satisfied current Canadian guidelines for receiving enzyme replacement therapy for Fabry disease. Following treatment with animal component-free bioreactor-processed agalsidase alfa, treatment-emergent adverse events were monitored, and post hoc analyses of infusion-related reactions by antidrug antibody and neutralizing antibody statuses were conducted. The data were analyzed using descriptive statistics.

Results

A total of 167 patients (mean [standard deviation] age, 48.9 [14.8] years), including six pediatric patients (< 18 years of age), received at least one full or partial infusion of agalsidase alfa animal component-free. Fewer than 5% of treatment-emergent adverse events (212/4446) observed in 40 patients were reported as infusion-related reactions. Antidrug antibody and neutralizing antibody status did not affect the proportion of patients with infusion-related reactions. No clinically significant changes in vital signs were observed in patients over the course of the study.

Conclusions

Long-term treatment with bioreactor-produced agalsidase alfa animal component-free did not reveal new safety signals in this population of Canadian patients with Fabry disease. The treatment-emergent adverse event profile was consistent with the clinical manifestations of the disease and the known safety profile of roller bottle-produced agalsidase alfa.

Clinical Trial Registration

ClinicalTrials.gov identifier NCT01298141.

Prompt Agalsidase Alfa Therapy Initiation is Associated with Improved Renal and Cardiovascular Outcomes in a Fabry Outcome Survey Analysis

Background

The timing of enzyme replacement therapy initiation in patients with Fabry disease is hypothesized to be critical. In this study, we used Fabry Outcome Survey data to assess the impact of prompt versus delayed initiation of treatment with agalsidase alfa on cardiovascular and renal events in patients with Fabry disease.

Methods

Available genetic data at baseline were used to define patients with mutations associated with classical versus late-onset Fabry disease. Time to cardiovascular or renal events, from treatment initiation until 120 months, was compared for patients in prompt versus delayed groups. "Prompt" was defined as treatment initiation <24 months from symptom onset (analysis A) or diagnosis (analysis B), and "delayed" was defined as ≥24 months from symptom onset (analysis A) or diagnosis (analysis B). Kaplan-Meier curves and Log rank tests compared event-free probabilities and time to first event. Multivariate Cox regression estimated hazard ratios (HRs).

Results

Analysis by time from symptom onset included 1374 patients (172 prompt, 1202 delayed). In a multivariate Cox regression analysis, prompt versus delayed treatment initiation significantly reduced the probability of cardiovascular (HR=0.62; P<0.001) and renal (HR=0.57; P=0.001) events. History of cardiovascular or renal events was associated with increased risk of respective events. Analysis by time from diagnosis included 2051 patients (1006 prompt, 1045 delayed). In a multivariate Cox regression analysis, prompt treatment initiation significantly reduced the probability of cardiovascular events (HR=0.83; P=0.003) after adjusting for history of cardiovascular events, sex, and age at treatment initiation. Univariate analysis showed that the probability of renal events was significantly lower in the prompt group (P=0.018); this finding was attenuated in the multivariate Cox regression analysis.

Conclusion

This analysis suggests that prompt treatment initiation with agalsidase alfa provided better renal and cardiovascular outcomes than delayed treatment in patients with Fabry disease.

Precision medicine in Fabry disease

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A (GLA) gene, leading to a deficiency in α-galactosidase A. The lysosomal accumulation of glycosphingolipids, primarily globotriaosylceramide (Gb3) and its deacylated form, globotriaosylsphingosine (lyso-Gb3), results in progressive renal failure, cardiomyopathy associated with cardiac arrhythmia and recurrent cerebrovascular events, significantly limiting life expectancy in affected patients. In male patients, a definitive diagnosis of FD involves demonstrating a GLA deficiency in leucocytes. In females, because of the potential high residual enzymatic activity, the diagnostic gold standard requires molecular genetic analyses. The current treatment options for FD include recombinant enzyme replacement therapies (ERTs) with intravenous agalsidase-α (0.2 mg/kg body weight) or agalsidase-β (1 mg/kg body weight) every 2 weeks as well as an oral pharmacological chaperone (migalastat 123 mg every other day) that selectively and reversibly binds to the active sites of amenable mutant forms of the GLA enzyme. These therapies facilitate cellular Gb3 clearance and an overall improvement of disease burden. However, ERT can lead to infusion-associated reactions, as well as the formation of neutralizing anti-drug antibodies in ∼40% of all ERT-treated males, leading to an attenuation of therapy efficacy. This article reviews the clinical presentation, diagnosis and interdisciplinary clinical management of FD and discusses the therapeutic options, with a special focus on precision medicine, accounting for individual variability in genetic mutations, Gb3 and lyso-Gb3 levels, allowing physicians to predict more accurately which prevention and treatment strategy is best for which patient.

Treatment of Anderson-Fabry Disease

Fabry disease is an X-linked disorder of glycosphingolipid metabolism that results in progressive accumulation of neutral glycosphingolipids, predominantly globotriaosylsphingosine (Gb3) in lysosomes, as well as other cellular compartments of several tissues, causing multi-organ manifestations (acroparesthesias, hypohidrosis, angiokeratomas, signs and symptoms of cardiac, renal, cerebrovascular involvement). Pathogenic mutations lead to a deficiency of the lysosomal enzyme alpha-galactosidase A (GLA). In the presence of high clinical suspicion, a careful physical examination and specific laboratory tests are required. Finally, the diagnosis of Fabry's disease is confirmed by the demonstration of the absence of or reduced alpha-galactosidase A enzyme activity in hemizygous men and gene typing in heterozygous females. Measurement of the biomarkers Gb3 and Lyso Gb3 in biological specimens may facilitate diagnosis. The current treatment of Anderson-Fabry disease is represented by enzyme replacement therapy (ERT) and oral pharmacological chaperone. Future treatments are based on new strategic approaches such as stem cell-based therapy, pharmacological approaches chaperones, mRNA therapy, and viral gene therapy. This review outlines the current therapeutic approaches and emerging treatment strategies for Anderson-Fabry disease.

Fabry disease-what cardiologists can learn from the nephrologist: a narrative review

Fabry disease (FD) is a rare, X-linked lysosomal storage disorder resulting in decreased or absent activity of the lysosomal enzyme alpha-galactosidase A. Subsequent accumulation of storage material can occur in virtually all cells of the body. Organs and structures affected by storage material deposition include the heart, the kidney, the central and peripheral nervous system and the cornea of the eyes. Progressive cardiac hypertrophy, arrhythmias, cardiac fibrosis, heart failure and cardiac death are common characteristics of cardiac involvement. Renal depositions of glycosphingolipids are already detectable in childhood. An early clinical sign of Fabry renal involvement is albuminuria, often preceding a detectable loss of kidney function. Later in life Fabry patients may exhibit a progressive decline of their kidney function leading to end-stage renal disease (ESRD). The clinical presentation of Fabry patients regarding renal involvement depends on the underlying mutation in the GLA gene. Classically affected males typically show a gradual decrease in kidney function, patients with mild or late onset mutations as well as a subgroup of females may exhibit only little or no renal abnormalities. This review summarizes the characteristics of renal involvement in FD, the diagnostics necessary to evaluate the degree of renal impairment and possible treatment options.

Contemporary therapeutics and new drug developments for treatment of Fabry disease: a narrative review

Fabry disease (OMIM 301500) is an X-linked (Xq22.1) lysosomal storage disorder leading to a progressive multisystem disease with high variability in both genotype and phenotype expression. The pathophysiological origin is found in an enzyme deficiency of the α-galactosidase A (enzyme commission no. 3.2.1.22) leading to accumulation of globotriaosylceramides in all lysosome carrying tissue. Especially organ manifestations of the heart, kidneys and nervous system are of significant prognostic value and might complicate with Fabry-associated pain, young aged cryptogenic stroke, proteinuria, kidney failure, hypertrophic cardiomyopathy, heart failure, malign cardiac rhythm disturbances and eventually sudden cardiac death. Up to the introduction of the first enzyme replacement agent in 2001, patients faced the disease's natural course with no disease-specific therapies available. Today, two recombinant enzyme replacement agents (Fabrazyme^®, Sanofi Genzyme, Cambridge, MA, USA; Replagal^®, Takeda Pharmaceutical, Tokio, Japan) and one oral chaperone therapy (Migalastat^®, Amicus Therapeutics, USA) are available and well-established in daily clinical practice. Substrate reduction therapy, second-generation enzyme replacement agents and different gene therapy approaches are currently undergoing preclinical and clinical trial phases and aim to improve therapeutic success and long-term outcome of patients with Fabry disease. This narrative review summarizes the currently available therapeutic options and future perspectives in Fabry disease.

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.

Kidney Transplant in Fabry Disease: A Revision of the Literature

Fabry disease is classified as a rare X-linked disease caused by a complete or partial defect of enzyme alpha-galactosidase, due to GLA gene mutations. This disorder leads to intracellular globotriaosylceramide (Gb3) deposition associated with increased Gb3 plasma levels. Most of the symptoms of the disease, involving kidneys, heart and nervous system, result from this progressive Gb3 deposition. The incidence is estimated in 1/50,000 to 1/117,000 in males. Fabry nephropathy begins with microalbuminuria and/or proteinuria, which, in the classic form, appear from childhood. Thus, a progressive decline of renal function can start at a young age, and evolve to kidney failure, requiring dialysis or renal transplantation. Enzyme replacement therapy (ERT), available since 2001 for Fabry disease, has been increasingly introduced into the clinical practice, with overall positive short-term and long-term effects in terms of ventricular hypertrophy and renal function. Kidney transplantation represents a relevant therapeutic option for Fabry nephropathy management, for patients reaching end-stage renal disease, but little is known about long-term outcomes, overall patient survival or the possible role of ERT after transplant. The purpose of this review is to analyze the literature on every aspect related to kidney transplantation in patients with Fabry nephropathy: from the analysis of transplant outcomes, to the likelihood of disease recurrence, up to the effects of ERT and its possible interference with immunosuppression.

Age-related renal function decline in Fabry disease patients on enzyme replacement therapy: a longitudinal cohort study

BACKGROUND

Nephropathy is common in Fabry disease (FD). Prior studies of renal function during enzyme replacement therapy (ERT) have primarily used estimated glomerular filtration rate (eGFR). We studied the attrition of renal function in FD by measured GFR (mGFR) and urine protein excretion, and explored the influence of age.

METHODS

This was a long-term observational study of a nationwide, family-screened cohort of FD patients. All Danish genetically verified FD patients on ERT, without end-stage renal disease at baseline and with three or more mGFR values were included.

RESULTS

In all, 52 patients with consecutive mGFR values (n = 841) over median 7 years (range 1-13) were evaluated. Blood pressure remained normal and urine protein excretion was unchanged. Plasma globotriaosylceramide (Gb-3) levels normalized while plasma lyso-Gb-3 remained abnormal in 34% of patients. Baseline mGFR was 90 ± 3 mL/min/1.73 m2 and rate of renal function loss 0.9 ± 0.2 mL/min/1.73 m2/year. Baseline eGFR was 97 ± 5 mL/min/1.73 m2 and rate of renal function loss 0.8 ± 0.3 mL/min/1.73 m2/year. mGFR was age- adjusted to renal healthy non-FD subjects, giving a standard deviation score of -0.8 ± 0.2 with an annual slope of -0.03 ± 0.01 (P = 0.099), without differences between genders. Age grouping of age-adjusted data showed exaggerated renal function loss with age. Urine albumin-creatinine ratio (UACR) >300 mg/g was associated with faster renal function loss, independent of baseline mGFR, age and gender.

CONCLUSIONS

ERT-treated FD patients did not have a faster attrition of renal function than renal healthy non-FD subjects (background population). The rate of renal function loss with age was independent of gender and predicted by high UACR. We suggest cautious interpretation of non-age-adjusted FD renal data.

Why systematic literature reviews in Fabry disease should include all published evidence

Fabry disease is an X-linked inherited, progressive disorder of lipid metabolism resulting from the deficient activity of the enzyme α-galactosidase. Enzyme replacement therapy (ERT) with recombinant agalsidase, with intravenous infusions of either agalsidase beta or agalsidase alfa, is available and clinical experience now exceeds 15 years. There are very few randomised, placebo-controlled clinical trials evaluating the outcomes of ERT. Data are often derived from observational, registry-based studies and case reports. Pooled analysis of data from different sources may be limited by the heterogeneity of the patient populations, outcomes and treatment. Therefore, comprehensive systematic literature reviews of unpooled data are needed to determine the effects of ERT on disease outcomes. A systematic literature search was conducted in the Embase and PubMed (MEDLINE) databases to retrieve original articles that evaluated outcomes of ERT in patients with Fabry disease; the outcome data were analysed unpooled. The literature analysis included the full range of published literature including observational studies and case series/case reports. Considerable heterogeneity was found among the studies, with differences in sample size, statistical methods, ERT regimens and patient demographic and clinical characteristics. We have demonstrated the value of performing an unpooled systematic literature review of all published evidence of ERT outcomes in Fabry disease, highlighting that in a rare genetic disorder like Fabry disease, which is phenotypically diverse, different patient populations can require different disease management and therapeutic goals depending on age, genotype, and disease severity/level of organ involvement. In addition, these findings are valuable to guide the design and reporting of new clinical studies.

Safety and effectiveness of enzyme replacement therapy with agalsidase alfa in patients with Fabry disease: Post-marketing surveillance in Japan

Fabry disease is a rare X-linked inherited multisystem disorder resulting from deficiency of the lysosomal enzyme alpha-galactosidase A. Currently, specific therapies, including enzyme replacement therapies, are available for Fabry disease, but clinical trials provide limited information on long-term safety and effectiveness. Agalsidase alfa was approved in Japan in 2006. The post-marketing surveillance study of all patients receiving agalsidase alfa to evaluate its long-term safety and effectiveness as a mandatory condition for its approval had been conducted for 8 years (from February 2007 to March 2015). A total of 493 patients were included in this analysis of safety and effectiveness. The overall mean follow-up period was 3.5 years (range, 0.0-7.9 years). The percentage of patients with adverse drug reactions was 24.5% (121/493) and 12.6% had infusion-related reactions (62/493). In the 256 patients without prior enzyme replacement therapy whose IgG antibody data were available, 17 were IgG antibody positive (6.6%). However, the chronological correlation between seroconversion and the incidence of infusion-related reactions was not clear. The mean brief pain inventory score of the worst pain decreased in patients with moderate and severe pain at baseline. Plasma Gb₃ and urine sediment Gb₃ in males with classical Fabry disease without prior enzyme replacement therapy significantly decreased. The mean yearly changes in eGFR (mL/min/1.73 m²) ranged from -2.88 to +1.00 in males with classical Fabry disease, from -2.04 to -0.95 in males with non-typical variant and from -2.64 to -1.02 in females. The lower eGFR or the more proteinuria at baseline, the faster the decrease in eGFR of the patients was observed. There was no substantial difference in cardiac parameters (left ventricular mass index, E/A wave ratio, ejection fraction, and QRS duration). In conclusion, agalsidase alfa, 0.2 mg/kg every other week, was well tolerated and controlled the progression of symptoms (especially renal and cardiac) of Fabry disease in adults. Enzyme replacement therapy should be started in Japanese patients before cardiac and/or renal symptoms of Fabry disease develop.

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

BACKGROUND

Heterozygous females with Fabry disease have a wide range of clinical phenotypes depending on the nature of their mutation and their X-chromosome inactivation pattern; it is therefore important to examine outcomes of enzyme replacement therapy (ERT) in the female patient population specifically. This paper presents the findings of a systematic literature review of treatment outcomes with ERT in adult female patients.

METHODS

A comprehensive systematic literature review was conducted through January 2017 to retrieve published papers with original data on ERT in the treatment of Fabry disease. The review included all original articles that presented ERT outcomes data on patients with Fabry disease, irrespective of the study type.

RESULTS

Clinical evidence for the efficacy of ERT in female patients was available from 67 publications including six clinical trial publications, and indicates significant reductions in plasma and urine globotriaosylceramide (GL-3) accumulation (in female patients with elevated pre-treatment levels) and improvements in cardiac parameters and quality of life (QoL). To date, data are insufficient to conclude on the effects of ERT on the nervous system, gastrointestinal manifestations, and pain in female patients with Fabry disease.

CONCLUSIONS

This review of available literature data demonstrates that ERT in adult female patients with Fabry disease has a beneficial effect on GL-3 levels and cardiac outcomes. The current evidence also suggests that ERT may improve QoL in this patient population, though further studies are needed to examine these results.

Efficacy of the pharmacologic chaperone migalastat in a subset of male patients with the classic phenotype of Fabry disease and migalastat-amenable variants: data from the phase 3 randomized, multicenter, double-blind clinical trial and extension study

PURPOSE

Outcomes in patients with Fabry disease receiving migalastat during the phase 3 FACETS trial (NCT00925301) were evaluated by phenotype.

METHODS

Data were evaluated in two subgroups of patients with migalastat-amenable GLA variants: "classic phenotype" (n = 14; males with residual peripheral blood mononuclear cell α-galactosidase A <3% normal and multiorgan system involvement) and "other patients" (n = 36; males not meeting classic phenotype criteria and all females). Endpoints included estimated glomerular filtration rate (eGFR), left ventricular mass index (LVMi), Gastrointestinal Symptoms Rating Scale diarrhea subscale (GSRS-D), renal peritubular capillary (PTC) globotriaosylceramide (GL-3) inclusions, and plasma globotriaosylsphingosine (lyso-Gb₃).

RESULTS

Baseline measures in the classic phenotype patients suggested a more severe phenotype. At month 24, mean (SD) annualized change in eGFR_CKD-EPI with migalastat was -0.3 (3.76) mL/min/1.73 m² in the classic phenotype subgroup; changes in LVMi, GSRS-D, and lyso-Gb₃ were -16.7 (18.64) g/m², -0.9 (1.66), and -36.8 (35.78) nmol/L, respectively. At month 6, mean PTC GL-3 inclusions decreased with migalastat (-0.8) and increased with placebo (0.3); switching from placebo to migalastat, PTC inclusions decreased by -0.7. Numerically smaller changes in these endpoints were observed in the other patients.

CONCLUSION

Migalastat provided clinical benefit to patients with Fabry disease and amenable variants, regardless of disease severity.

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.

New Fabry disease mutation confirms cardiomyopathy aetiology: a case report

Background

Aetiologic diagnosis should be a priority in cardiomyopathy patients, as some of them may benefit from efficient specific treatment. To achieve this, the best approach is to look for clinical and paraclinical ‘red flags’.

Case summary

A 55-year-old woman was referred to our centre with the diagnoses of hypertrophic cardiomyopathy (HCM), high blood pressure and dyslipidaemia. The only symptom she declared was long-term acroparesthaesia with an otherwise normal clinical exam. Lab work-up showed slightly above normal values of troponin and brain natriuretic peptide (BNP), and chronic kidney disease Stage IIIA. Both the electrocardiogram (ECG) and the echocardiography showed signs of biventricular HCM, with short PR interval on the ECG and longitudinal systolic dysfunction on the echo. Family history revealed that her son and brother had been diagnosed with Fabry disease (FD). She was then tested for FD and the results confirmed the diagnosis. Alpha-galactosidase (AGAL) levels were low and she had a severe mutation on the GLA gene (gross deletion of 3’ region of the GLA gene including coding parts of exon 7), not described before. The patient was started on specific enzyme therapy.

Discussion

Fabry disease is a rare X-linked disease caused by mutations on the GLA gene, which leads to low levels of AGAL and accumulation of globotriaosylceramide in the lysosomes of most tissues. Even though FD is X-linked, current medical knowledge states that most females are not mere carriers, but often present with a milder or later-onset phenotype.

European expert consensus statement on therapeutic goals in Fabry disease

BACKGROUND

Fabry disease, an inherited lysosomal storage disorder, causes multi-organ pathology resulting in substantial morbidity and a reduced life expectancy. Although Fabry disease is an X-linked disorder, both genders may be affected, but generally to a lesser extent in females. The disease spectrum ranges from classic early-onset disease to non-classic later-onset phenotypes, with complications occurring in multiple organs or being confined to a single organ system depending on the stage of the disease. The impact of therapy depends upon patient- and disease-specific factors and timing of initiation.

METHODS

A European panel of experts collaborated to develop a set of organ-specific therapeutic goals for Fabry disease, based on evidence identified in a recent systematic literature review and consensus opinion.

RESULTS

A series of organ-specific treatment goals were developed. For each organ system, optimal treatment strategies accounted for inter-patient differences in disease severity, natural history, and treatment responses as well as the negative burden of therapy and the importance of multidisciplinary care. The consensus therapeutic goals and proposed patient management algorithm take into account the need for early disease-specific therapy to delay or slow the progression of disease as well as non-specific adjunctive therapies that prevent or treat the effects of organ damage on quality of life and long-term prognosis.

CONCLUSIONS

These consensus recommendations help advance Fabry disease management by considering the balance between anticipated clinical benefits and potential therapy-related challenges in order to facilitate individualized treatment, optimize patient care and improve quality of life.

Fabry Nephropathy: An Evidence-Based Narrative Review

Fabry disease (FD) is a rare, X-linked disorder caused by mutations in the GLA gene encoding the enzyme α-galactosidase A. Complete or partial deficiency in this enzyme leads to intracellular accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in many cell types throughout the body, including the kidney. Progressive accumulation of Gb3 in podocytes, endothelial cells, epithelial cells, and tubular cells contribute to the renal symptoms of FD, which manifest as proteinuria and reduced glomerular filtration rate leading to renal insufficiency. A correct diagnosis of FD, although challenging, has considerable implications regarding treatment, management, and counseling. The diagnosis may be confirmed by demonstrating the enzyme deficiency in males and by identifying the specific GLA gene mutation in male and female patients. Treatment with enzyme replacement therapy, as part of the therapeutic strategy to prevent complications of the disease, may be beneficial in stabilizing renal function or slowing its decline, particularly in the early stages of the disease. Emergent treatments for FD include the recently approved chaperone molecule migalastat for patients with amenable mutations. The objective of this report is to provide an updated overview on Fabry nephropathy, with a focus on the most relevant aspects of its epidemiology, diagnosis, pathophysiology, and treatment options.

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.

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.

The Coexistence of Multiple Myeloma-associated Amyloid Light-chain Amyloidosis and Fabry Disease in a Hemodialysis Patient

Fabry disease (FD) is an inherited lysosomal disorder caused by an X-linked α-galactosidase A deficiency. We report the case of a 50-year-old male FD patient on hemodialysis who presented with macroglossia-related speaking difficulty and gastrointestinal symptoms. An endoscopic analysis revealed multiple gastric ulcers, and a histological examination led to a diagnosis of amyloid light-chain amyloidosis. Serum free light-chain and bone marrow analyses detected multiple myeloma (MM). Treatment with bortezomib and dexamethasone significantly improved the patient's symptoms. This is the first case to demonstrate a potential pathogenic relationship between FD and MM. The similar gastrointestinal manifestations might have contributed to the diagnostic difficulty.

Multicenter Female Fabry Study (MFFS) - clinical survey on current treatment of females with Fabry disease

BACKGROUND

The aim of the present study was to assess manifestations of and applied treatment concepts for females with Fabry disease (FD) according to the current European Fabry Guidelines.

METHODS

Between 10/2008 and 12/2014, data from the most recent visit of 261 adult female FD patients from six German Fabry centers were retrospectively analyzed. Clinical presentation and laboratory data, including plasma lyso-Gb3 levels were assessed.

RESULTS

Fifty-five percent of females were on enzyme replacement therapy (ERT), according to recent European FD guidelines. Thirty-three percent of females were untreated although criteria for ERT initiation were fulfilled. In general, the presence of left ventricular hypertrophy (LVH) seemed to impact more on ERT initiation than impaired renal function. In ERT-naïve females RAAS blockers were more often prescribed if LVH was present rather than albuminuria. Affected females with missense mutations showed a similar disease burden compared to females with nonsense mutations. Elevated plasma lyso-Gb3 levels in ERT-naïve females seem to be a marker of disease burden, since patients showed comparable incidences of organ manifestations even if they were ~8 years younger than females with normal lyso-Gb3 levels.

CONCLUSION

The treatment of the majority of females with FD in Germany is in line with the current European FD guidelines. However, a relevant number of females remain untreated despite organ involvement, necessitating a careful reevaluation of these females.

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.

Pathological Renal Findings of Chronic Renal Failure in a Patient with the E66Q Mutation in the α-galactosidase A Gene

A 66-year-old Japanese man was diagnosed with interstitial nephritis on a renal biopsy at 45 years of age and began to receive hemodialysis at 65 years of age. He was suspected of having Fabry disease as a result of a screening study for Fabry disease performed in hemodialysis patients. He had an E66Q mutation in the α-galactosidase A gene. We conducted an electron microscopic examination of a renal biopsy specimen obtained when the patient was diagnosed with chronic renal failure at 45 years of age in order to elucidate the pathogenicity of the E66Q mutation. Interestingly, an electron microscopic examination of the renal biopsy specimen indicated no characteristic findings of Fabry disease.

The prevalence and epidemiology of genetic renal disease amongst adults with chronic kidney disease in Australia

BACKGROUND

There are an established and growing number of Mendelian genetic causes for chronic kidney disease (CKD) in adults, though estimates of prevalence have been speculative. The CKD Queensland (CKD.QLD) registry enables partial clarification of this through the study of adults with CKD receiving nephrology care throughout Queensland, Australia.

METHODS

Data from the first 2,935 patients consented to the CKD.QLD registry across five sites was analysed, with a comparison between those with and without Genetic Renal Disease (GRD). Prevalence of GRD amongst those with diagnosed CKD, the general population, and commencing renal replacement therapy (RRT) was calculated using the CKD.QLD registry, national census data and extracted Australian and New Zealand Dialysis and Transplantation (ANZDATA) registry report data respectively.

RESULTS

Patients with GRD constituted 9.8% of this Australian adult CKD cohort (287/2935). This was lower than in local incident RRT cohorts (2006-2011: 9.8% vs 11.3%, x2 = 0.014). Cases of adult CKD GRD were more likely to be female (54.0% vs 45.6%; x2 = 0.007), younger (mean 52.6 yrs vs 69.3 yrs, p < 0.001), have a higher eGFR (mean 49.7 ml/min/1.73 m2 vs 40.4 ml/min/1.73 m2, p < 0.001), and have earlier stage renal disease (CKD Stage 1: 15.7% vs 5.1%, x2 < 0.0005) than those without GRD.

CONCLUSIONS

The proportion of GRD amongst an Australian adult CKD population in specialty renal practice is similar to past estimations. GRD is a significant cause for CKD and for RRT commencement, presenting opportunities for ongoing longitudinal study, directed therapeutics and clinical service redesign.

The kidney in Fabry's disease

Fabry disease (FD) is an X-linked disease in which mutations of the GLA gene result in a deficiency of the enzyme α-galactosidase A and subsequent progressive, intralysosomal deposition of undegraded glycosphingolipid products, primarily globotriaosylceramide, in multiple organs. Progressive nephropathy is one of the main features of FD and is marked by an insidious development, with an overall rate of progression of chronic kidney disease (CKD) very similar to diabetic nephropathy. Untreated patients usually develop end stage renal disease in their 50s. The decline in renal function in FD is adversely affected by male gender, advanced CKD, hypertension and, in particular, severe proteinuria. Enzyme replacement therapy (ERT) has been shown to slow the progression of Fabry nephropathy. The current consensus is that ERT should be started in all men and women with signs of renal involvement.

Fabry nephropathy: a review - how can we optimize the management of Fabry nephropathy?

Fabry disease is a rare, X-linked, lysosomal storage disease caused by mutations in the gene encoding the enzyme alpha-galactosidase A. Complete or partial deficiency in this enzyme leads to intracellular accumulation of globotriaosylceramide (Gb₃) and related glycosphingolipids in many cell types throughout the body, including the kidney. Progressive accumulation of Gb₃ in podocytes, epithelial cells and the tubular cells of the distal tubule and loop of Henle contribute to the renal symptoms of Fabry disease, which manifest as proteinuria and reduced glomerular filtration rate leading to chronic kidney disease and progression to end-stage renal disease. Early diagnosis and timely initiation of treatment of Fabry renal disease is an important facet of disease management. Initiating treatment with enzyme replacement therapy (ERT; agalsidase alfa, Replagal^®, Shire; agalsidase beta, Fabrazyme^®, Genzyme) as part of a comprehensive strategy to prevent complications of the disease, may be beneficial in stabilizing renal function or slowing its decline. Early initiation of ERT may also be more effective than initiating therapy in patients with more advanced disease. Several strategies are required to complement the use of ERT and treat the myriad of associated symptoms and organ involvements. In particular, patients with renal Fabry disease are at risk of cardiovascular events, such as high blood pressure, cardiac arrhythmias and stroke. This review discusses the management of renal involvement in Fabry disease, including diagnosis, treatments, and follow-up, and explores recent advances in the use of biomarkers to assist with diagnosis, monitoring disease progression and response to treatment.

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.

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.