Retrospective study of long-term outcomes of enzyme replacement therapy in Fabry disease: Analysis of prognostic factors

Effects of Enzyme Replacement Therapy on Cardiac MRI Findings in Fabry Disease: A Systematic Review and Meta-Analysis

Purpose To perform a systematic review and meta-analysis to assess the effect of enzyme replacement therapy on cardiac MRI parameters in patients with Fabry disease. Materials and Methods A systematic literature search was conducted from January 1, 2000, through January 1, 2024, in PubMed, ClinicalTrials.gov, Embase, and Cochrane Library databases. Study outcomes were changes in the following parameters: (a) left ventricular wall mass (LVM), measured in grams; (b) LVM indexed to body mass index, measured in grams per meters squared; (c) maximum left ventricular wall thickness (MLVWT), measured in millimeters; (d) late gadolinium enhancement (LGE) extent, measured in percentage of LVM; and (e) native T1 mapping, measured in milliseconds. A random-effects meta-analysis of the pooled mean differences between baseline and follow-up parameters was conducted. The study protocol was registered in PROSPERO (CRD42022336223). Results The final analysis included 11 studies of a total of 445 patients with Fabry disease (mean age ± SD, 41 years ± 11; 277 male, 168 female). Between baseline and follow-up cardiac MRI, the following did not change: T1 mapping (mean difference, 6 msec [95% CI: -2, 15]; two studies, 70 patients, I2 = 88%) and LVM indexed (mean difference, -1 g/m2 [95% CI: -6, 3]; four studies, 290 patients, I2 = 81%). The following measures minimally decreased: LVM (mean difference, -18 g [95% CI: -33, -3]; seven studies, 107 patients, I2 = 96%) and MLVWT (mean difference, -1 mm [95% CI: -2, -0.02]; six studies, 151 patients, I2 = 90%). LGE extent increased (mean difference, 1% [95% CI: 1, 1]; three studies, 114 patients, I2 = 85%). Conclusion In patients with Fabry disease, enzyme replacement therapy was associated with stabilization of LVM, MLVWT, and T1 mapping values, whereas LGE extent mildly increased. Keywords: Fabry Disease, Enzyme Replacement Therapy (ERT), Cardiac MRI, Late Gadolinium Enhancement (LGE) Supplemental material is available for this article. © RSNA, 2024.

The Effect of Fabry Disease Therapy on Bone Mineral Density

Fabry disease (FD) is an X-linked lysosomal storage disorder, characterised by the cellular accumulation of globotriaosylceramide due to impaired alpha-galactosidase A enzyme activity. FD may manifest with multisystem pathology, including reduced bone mineral density (BMD). Registry data suggest that the introduction of Fabry-specific therapies (enzyme replacement therapy or chaperone therapy) has led to significant improvements in overall patient outcomes; however, there are limited data on the impact on bone density. The aim of this study was to describe the effect of Fabry-specific therapies on longitudinal changes in bone mineral density (BMD) in FD. We performed a retrospective observational study analysing bone densitometry (DXA) in patients with genetically confirmed FD. Patients were grouped based on the use of Fabry-specific therapies. The between-group longitudinal change in BMD Z-score was analysed using linear mixed effects models. A total of 88 FD patients were analysed (50 untreated; 38 treated). The mean age at first DXA was 38.5 years in the untreated group (84% female) and 43.7 years in the treated group (34% female). There was no significant longitudinal between-group difference in the BMD Z-score at the lumbar spine. However, the Z-score per year at the total hip (β = -0.105, p < 0.001) and femoral neck (β = -0.081, p = 0.001) was significantly lower over time in the treated than the untreated group. This may reflect those receiving therapy having a more severe underlying disease. Nevertheless, this suggests that Fabry-specific therapies do not reverse all disease mechanisms and that the additional management of BMD may be required in this patient population.

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.

Long-term safety and efficacy of pegunigalsidase alfa: A multicenter 6-year study in adult patients with Fabry disease

PURPOSE

Fabry disease (FD) is a rare lysosomal storage disorder caused by pathogenic variants in the GLA gene encoding α-galactosidase (α-Gal)-A. We evaluated long-term safety/efficacy of pegunigalsidase alfa, a novel PEGylated α-Gal-A enzyme replacement therapy (ERT) now approved for FD.

METHODS

In a phase-1/2 dose-ranging study, 15 ERT-naive adults with FD completed 12 months of pegunigalsidase alfa and enrolled in this 60-month open-label extension of 1 mg/kg pegunigalsidase alfa infusions every 2 weeks.

RESULTS

Fifteen patients enrolled (8 males; 7 females); 10 completed ≥48 months (60 months total treatment), and 2 completed 60 months (72 months total treatment). During treatment, most treatment-emergent adverse events were mild/moderate in severity and all infusion-related reactions were mild/moderate in severity. Four patients were transiently positive for anti-pegunigalsidase alfa IgG. Patients showed continuous reduction in plasma lyso-Gb3 concentrations with mean (standard error) reduction of 76.1 [25.1] ng/mL from baseline to month 24. At 60 months, the estimated glomerular filtration rate slope was comparable to that observed in patients treated with other ERTs. Cardiac function assessments revealed stability; no cardiac fibrosis was observed.

CONCLUSION

In this first long-term assessment of pegunigalsidase alfa administration in patients with FD, we found favorable safety/efficacy. Our data suggest long-term continuous benefits of pegunigalsidase alfa treatment in adults with FD.

Fabry Disease Nephropathy: Histological Changes With Nonclassical Mutations and Genetic Variants of Unknown Significance

RATIONALE & OBJECTIVE

Fabry disease (FD) is an X-linked genetic disorder that causes lysosomal storage of glycosphingolipids, primarily globotriaosylceramide (Gb3) and its derivative globotriaosylsphingosine (lyso-Gb3), with multiorgan dysfunction including chronic kidney disease. Affected individuals may be carriers of gene variants that are of uncertain significance (GVUS). We describe kidney pathology at the early stages of FD-related kidney disease to gain insights into its association with GVUS and sex.

STUDY DESIGN

Single-center, case series.

SETTING & PARTICIPANTS

Thirty-five consecutively biopsied patients (aged 48.1±15.4 years, 22 females) from among 64 patients with genetically diagnosed FD. Biopsies were retrospectively screened using the International Study Group of Fabry Nephropathy Scoring System.

OBSERVATIONS

Genetic mutation type, p.N215S and D313Y, sex, age, estimated glomerular filtration rate (eGFR), plasma lyso-Gb3 (pLyso-Gb3) levels, and histological parameters, including Gb3 deposits were recorded. Genetic analyses showed mostly missense mutations, p.N215S variant in 15, and the "benign polymorphism" D313Y in 4 of the biopsied patients. Morphological lesions were similar for men and women except for interstitial fibrosis and arteriolar hyalinosis being more common in men. Early in their clinical course, patients with normal/mild albuminuria had podocyte, tubular, and peritubular capillary vacuoles/inclusions, and evidence of chronicity, i.e., glomerulosclerosis, interstitial fibrosis, tubular atrophy. These findings appeared to be associated with pLyso-Gb3, eGFR, and age.

LIMITATIONS

Retrospective design and inclusion of outpatients partially based on family pedigree.

CONCLUSIONS

In early stages of kidney disease in the setting of FD, numerous histological abnormalities are present. These observations suggest that kidney biopsies early in FD may reveal activity of kidney involvement that may inform clinical management.

Targeted literature review exploring the predictive value of estimated glomerular filtration rate and left ventricular mass index as indicators of clinical events in Fabry disease

BACKGROUND

Fabry disease is a rare, progressive X-linked lysosomal storage disorder. It is caused by mutations in the GLA gene resulting in deficiency of α-galactosidase A (α-Gal A), leading to peripheral neuropathy, cardiovascular disease, stroke, end-stage renal disease, gastrointestinal disorders and premature death. Given the long-term nature of disease progression, trials in Fabry disease are often not powered to capture these clinical events. Clinical measures such as estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMI) are often captured instead. eGFR and LVMI are believed to be associated with long-term Fabry disease clinical events of interest, but the precise relationships are unclear.

OBJECTIVE

We aimed to identify published literature exploring the link between eGFR/LVMI and long-term clinical events in Fabry disease.

METHODS

A comprehensive literature search was conducted in Embase® and MEDLINE® (using Embase.com), and a targeted literature review was conducted. Studies reporting a quantitative relationship between eGFR and/or LVMI and clinical events in Fabry disease were extracted, and narrative synthesis was conducted to understand these predictive relationships.

RESULTS

Eight studies, consisting of seven patient-level retrospective analyses plus one prospective cohort study, met the inclusion criteria. Seven of these studies reported eGFR and six reported LVMI, with five reporting both. All studies presented results for either a composite measure including a range of key Fabry disease clinical events, or a composite outcome that included at least one key Fabry disease clinical event. All studies employed Cox proportional hazards survival modelling. The studies consistently reported that eGFR and LVMI are predictors of key clinical events in Fabry disease, with the findings remaining consistent regardless of the therapy received by patients in the studies.

CONCLUSIONS

The evidence identified suggests that eGFR and LVMI outcomes may be appropriate indicators for long-term clinical events in Fabry disease, and all identified papers implied the same directional relationship. However, additional research is needed to further understand the specific details of these relationships and to quantify them.

Early Risk Stratification for Natural Disease Course in Fabry Patients Using Plasma Globotriaosylsphingosine Levels

BACKGROUND

Fabry disease is a very heterogeneous X-linked lysosomal storage disease. Disease manifestations in the kidneys, heart, and brain vary greatly, even between patients of the same sex and with the same disease classification (classical or nonclassical). A biomarker with a strong association with the development of disease manifestations is needed to determine the need for Fabry-specific treatment and appropriate frequency of follow-up because clinical manifestations of the disorder may take decennia to develop.

METHODS

We investigated the levels of plasma lysoGb3 levels over time and its association with disease manifestations and disease course in 237 untreated patients with Fabry disease (median age 42 years, 38% male) using linear mixed-effect models.

RESULTS

LysoGb3 levels are stable over time in plasma of untreated patients with Fabry disease. Higher levels of lysoGb3 were associated with steeper decline in eGFR ( P = 0.05) and a faster increase in albuminuria (measured as the urinary albumin-to-creatinine ratio, P < 0.001), left ventricular mass (measured on echocardiography, P < 0.001), left atrial volume index ( P = 0.003), and Fazekas score ( P = 0.003). In addition, regardless of age, higher lysoGb3 levels were associated with higher relative wall thickness ( P < 0.001) and unfavorable functional markers on echocardiography, including septal mitral annular early diastolic velocity (e', P < 0.001) and the ratio of early transmitral velocity (E) to e' (E/e', P = 0.001).

CONCLUSIONS

In an individual patient with Fabry disease, the plasma lysoGb3 level reached a specific level in early childhood which, in the absence of Fabry-specific treatment, remained stable throughout life. The level of lysoGb3 in untreated patients was associated with nearly all Fabry-specific disease manifestations, regardless of the sex of the patient.

Consensus recommendations for the treatment and management of patients with Fabry disease on migalastat: a modified Delphi study

Objective

Fabry disease is a progressive disorder caused by deficiency of the α-galactosidase A enzyme (α-Gal A), leading to multisystemic organ damage with heterogenous clinical presentation. The addition of the oral chaperone therapy migalastat to the available treatment options for Fabry disease is not yet universally reflected in all treatment guidelines. These consensus recommendations are intended to provide guidance for the treatment and monitoring of patients with Fabry disease receiving migalastat.

Methods

A modified Delphi process was conducted to determine consensus on treatment decisions and monitoring of patients with Fabry disease receiving migalastat. The multidisciplinary panel comprised 14 expert physicians across nine specialties and two patients with Fabry disease. Two rounds of Delphi surveys were completed and recommendations on the use of biomarkers, multidisciplinary monitoring, and treatment decisions were generated based on statements that reached consensus.

Results

The expert panel reached consensus agreement on 49 of 54 statements, including 16 that reached consensus in round 1. Statements that reached consensus agreement are summarized in recommendations for migalastat treatment and monitoring, including baseline and follow-up assessments and frequency. All patients with Fabry disease and an amenable mutation may initiate migalastat treatment if they have evidence of Fabry-related symptoms and/or organ involvement. Treatment decisions should include holistic assessment of the patient, considering clinical symptoms and organ involvement as well as patient-reported outcomes and patient preference. The reliability of α-Gal A and globotriaosylsphingosine as pharmacodynamic response biomarkers remains unclear.

Conclusion

These recommendations build on previously published guidelines to highlight the importance of holistic, multidisciplinary monitoring for patients with Fabry disease receiving migalastat, in addition to shared decision-making regarding treatments and monitoring throughout the patient journey. GRAPHICAL ABSTRACT.

An expert consensus on the recommendations for the use of biomarkers in Fabry disease

Fabry disease is an X-linked lysosomal storage disorder caused by the accumulation of glycosphingolipids in various tissues and body fluids, leading to progressive organ damage and life-threatening complications. Phenotypic classification is based on disease progression and severity and can be used to predict outcomes. Patients with a classic Fabry phenotype have little to no residual α-Gal A activity and have widespread organ involvement, whereas patients with a later-onset phenotype have residual α-Gal A activity and disease progression can be limited to a single organ, often the heart. Diagnosis and monitoring of patients with Fabry disease should therefore be individualized, and biomarkers are available to support with this. Disease-specific biomarkers are useful in the diagnosis of Fabry disease; non-disease-specific biomarkers may be useful to assess organ damage. For most biomarkers it can be challenging to prove they translate to differences in the risk of clinical events associated with Fabry disease. Therefore, careful monitoring of treatment outcomes and collection of prospective data in patients are needed. As we deepen our understanding of Fabry disease, it is important to regularly re-evaluate and appraise published evidence relating to biomarkers. In this article, we present the results of a literature review of evidence published between February 2017 and July 2020 on the impact of disease-specific treatment on biomarkers and provide an expert consensus on clinical recommendations for the use of those biomarkers.

Cardiac magnetic resonance of hypertrophic heart phenotype: A review

Hypertrophic heart phenotype is characterized by an abnormal left ventricular (LV) thickening. A hypertrophic phenotype can develop as adaptive response in many different conditions such as aortic stenosis, hypertension, athletic training, infiltrative heart muscle diseases, storage disorders and metabolic disorders. Hypertrophic cardiomyopathy (HCM) is the most frequent primary cardiomyopathy (CMP) and a genetical cause of cardiac hypertrophy. It requires the exclusion of any other cause of LV hypertrophy. Cardiac magnetic resonance (CMR) is a comprehensive imaging technique that allows a detailed evaluation of myocardial diseases. It provides reproducible measurements and myocardial tissue characterization. In clinical practice CMR is increasingly used to confirm the presence of ventricular hypertrophy, to detect the underlying cause of the phenotype and more recently as an efficient prognostic tool. This article aims to provide a detailed overview of the applications of CMR in the setting of hypertrophic heart phenotype and its role in the diagnostic workflow of such condition.

Development of a Biosimilar of Agalsidase Beta for the Treatment of Fabry Disease: Preclinical Evaluation

BACKGROUND AND OBJECTIVE

Fabry disease (FD) is a rare lysosomal storage disorder caused by a deficiency of the enzyme α-galactosidase A (aGal A). Since 2001, two different enzyme replacement therapies have been authorized, with agalsidase beta being used in most parts of the Western world. Currently, biosimilars of several expensive enzyme therapies are under development to improve their accessibility for patients. We present the preclinical results of the development of a biosimilar to agalsidase beta.

METHODS

Produced in a Chinese hamster ovary (CHO)-cell system, the biosimilar aGal A Biosidus (AGABIO), was compared with agalsidase beta with respect to amino acid sequence, glycosylation, specific α-galactosidase activity, stability in plasma, and effects on cultured human Fabry fibroblasts and Fabry mice.

RESULTS

AGABIO had the same amino acid composition and similar glycosylation, enzymatic activity, and stability as compared with agalsidase beta. After uptake in fibroblasts, α-galactosidase A activity increased in a dose-dependent manner, with maximum uptake observed after 24 h, which remained stable until at least 48 h. Both enzymes were localized to lysosomes. Reduction of accumulated globotriaosylceramide (Gb3) and lysoGb3 in cultured Fabry fibroblasts by AGABIO and agalsidase beta showed comparable dose-response curves. In Fabry knockout mice, after a single injection, both enzymes were rapidly cleared from the plasma and showed equal reductions in tissue and plasma sphingolipids. Repeated dose studies in rats did not raise any safety concerns. Anti-drug antibodies from patients with FD treated with agalsidase beta showed equal neutralization activity toward AGABIO.

CONCLUSION

These findings support the biosimilarity of AGABIO in comparison with agalsidase beta. The clinical study phase is currently under development.

Palm-Plant Pain, Sign of a Severe Systemic Disease? Case Report and Review of Literature

Fabry disease is an X-linked lysosomal storage disease, second in prevalence after Gaucher disease. The onset of symptoms occurs in childhood or adolescence with palmo-plantar burning pains, hypo hidrosis, angiokeratomas, and corneal deposits. In the absence of diagnosis and treatment, the disease will progress to the late phase, characterized by progressive cardiac, cerebral and renal damage, and possible death. We present the case of an 11-year-old male boy who was transferred to the Pediatric Nephrology Department for palmo-plantar burning pain and end stage renal disease. Following the evaluations for the etiology of end stage renal disease we excluded the vasculitis, the neurologic diseases, extrapulmonary tuberculosis. Because of suggestive aspect at CT scan and lack of etiologic diagnosis of renal insufficiency we performed lymph node and kidney biopsy, with a surprising result for storage disease. The specific investigation confirmed the diagnosis.

Integrating Cardiac MRI Imaging and Multidisciplinary Clinical Care is Associated With Improved Outcomes in Patients With Fabry Disease

Given the inherent complexities of Fabry disease (FD) and evolving landscape of cardiovascular clinical management, there is no established ideal clinical care model for these patients. We identified clinical factors predictive of increased risk of major adverse cardiac events (MACE) in patients with FD targeted to improve clinical outcomes. Ninety-five patients studied over a median follow-up time of 6.3 years, and 26 patients reached the composite endpoint with a high prevalence of heart failure and cerebrovascular events and no cardiac-related mortality. Patients with MACE had worse health-related quality of life scores. Hypertrophy and presence of myocardial fibrosis increase risk of MACE by 4-5 times, and dyslipidemia increases risk of MACE by 3 times. Early Fabry-specific treatment and close monitoring of comorbidities reduce cardiac complications and mortality. These findings highlight the importance of comprehensive multidisciplinary management to help improve outcomes in FD patients.

Biopharmaceutical applications of α-galactosidases

α-Galactosidases are exoglycosidases that are active on galactose-containing side chains in oligosaccharides, polysaccharides, glycolipids, and glycoproteins. α-Galactosidases are gaining increased interest in human medicine, especially in the enzyme replacement therapy for Fabry's disease. α-Galactosidases with regioselectivity toward α-1,3-linked galactose find application in xenotransplantation and blood group transformation. The use of α-galactosidases as a therapeutic agent in alleviating the postprandial symptoms of irritable bowel syndrome is much acclaimed. The excellent therapeutic applications of α-galactosidases have led to an upwelling of worldwide research interventions to identify novel α-galactosidases with improved catalytic efficiency. In addition to these therapeutic applications, α-galactosidases also have interesting applications in the industrial sectors like food, feed, probiotics, sugar, and paper pulp. The current review focuses on the diverse therapeutic applications of α-galactosidases and their prospects.

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.

Olive Oil in the Mediterranean Diet and Its Biochemical and Molecular Effects on Cardiovascular Health through an Analysis of Genetics and Epigenetics

Human nutrition is a relatively new science based on biochemistry and the effects of food constituents. Ancient medicine considered many foods as remedies for physical performance or the treatment of diseases and, since ancient times, especially Greek, Asian and pre-Christian cultures similarly thought that they had beneficial effects on health, while others believed some foods were capable of causing illness. Hippocrates described the food as a form of medicine and stated that a balanced diet could help individuals stay healthy. Understanding molecular nutrition, the interaction between nutrients and DNA, and obtaining specific biomarkers could help formulate a diet in which food is not only a food but also a drug. Therefore, this study aims to analyze the role of the Mediterranean diet and olive oil on cardiovascular risk and to identify their influence from the genetic and epigenetic point of view to understand their possible protective effects.

Cardiac Magnetic Resonance in Fabry Disease: Morphological, Functional, and Tissue Features

Fabry disease (FD) is an X-linked inheritable storage disease caused by a deficiency of alpha-galactosidase causing lysosomal overload of sphingolipids. FD cardiomyopathy is characterized by left ventricular (LV) hypertrophy and should be considered in differential diagnosis with all the other causes of LV hypertrophy. An early diagnosis of FD is very important because the enzyme replacement therapy (ERT) may change the fate of patients by blocking both cardiac and systemic involvement and improving prognosis. Diagnosis may be relatively easy in young patients with the typical signs and symptoms of FD, but in male patients with late onset of disease and in females, diagnosis may be very challenging. Morphological and functional aspects are not specific to FD, which cannot be diagnosed or excluded by echocardiography. Cardiac magnetic resonance (CMR) with tissue characterization capability is an accurate technique for the differential diagnosis of LV hypertrophy. The finding of decreased myocardial T1 value in LV hypertrophy is specific to FD. Late gadolinium enhancement (LGE) is found in the late stage of the disease, but it is useful to predict the cardiac response to ERT and to stratify the prognosis.

Validated Model for Prediction of Adverse Cardiac Outcome in Patients With Fabry Disease

BACKGROUND

The cardiac manifestations of Fabry disease are the leading cause of death, but risk stratification remains inadequate. Identifying patients who are at risk of adverse cardiac outcome may facilitate more evidence-based treatment guidance. Contemporary cardiovascular cardiac magnetic resonance biomarkers have become widely adopted, but their prognostic value remains unclear.

OBJECTIVES

The objective of this study was to develop, internally validate, and evaluate the performance of, a prognostic model, including contemporary deep phenotyping, which can be used to generate individual risk estimates for adverse cardiac outcome in patients with Fabry disease.

METHODS

This longitudinal prospective cohort study consisted of 200 consecutive patients with Fabry disease undergoing clinical cardiac magnetic resonance. Median follow-up was 4.5 years (IQR: 2.7-6.3 years). Prognostic models were developed using Cox proportional hazards modeling. Outcome was a composite of adverse cardiac events. Model performance was evaluated. A risk calculator, which provides 5-year estimated risk of adverse cardiac outcome for individual patients, including men and women, was generated.

RESULTS

The highest performing, internally validated, parsimonious multivariable model included age, native myocardial T₁ dispersion (SD of per voxel myocardial T₁ relaxation times), and indexed left ventricular mass. Median optimism-adjusted c-statistic across 5 imputed model development data sets was 0.77 (95% CI: 0.70-0.84). Model calibration was excellent across the full risk profile.

CONCLUSIONS

This study developed and internally validated a risk prediction model that accurately predicts 5-year risk of adverse cardiac outcome for individual patients with Fabry disease, including men and women, which could easily be integrated into clinical care. External validation is warranted.

Cardiac involvement in Fabry disease - A non-invasive assessment and the role of specific therapies

Fabry disease is an X-linked inherited metabolic disorder due to the pathogenic mutation of the GLA gene, which codes lysosomal enzyme alpha-galactosidase A. The resultant accumulation of glycosphingolipids causes various systemic symptoms in childhood and adolescence, and major organ damage in adulthood. Cardiac involvement is important as the most frequent cause of death in Fabry disease patients. Progressive left ventricular hypertrophy with varying degrees of contractile dysfunction as well as conduction abnormalities and arrhythmias are typical cardiac features, and these findings can be evaluated in detail via non-invasive modalities, such as an electrocardiogram, echocardiography and cardiac magnetic resonance. In addition, specific therapies of enzyme replacement therapy and pharmacological chaperone therapy are available, and their beneficial effects on cardiac involvement have been reported. This minireview highlights recent evidence concerning non-invasive modalities for assessing cardiac involvement in Fabry disease and the effects of enzyme replacement therapy and pharmacological chaperone therapy on the findings of those modalities.

An expert consensus on practical clinical recommendations and guidance for patients with classic Fabry disease

Fabry disease is an X-linked inherited lysosomal disorder that causes accumulation of glycosphingolipids in body fluids and tissues, leading to progressive organ damage and reduced life expectancy. It can affect both males and females and can be classified into classic or later-onset phenotypes. In classic Fabry disease, α-galactosidase A (α-Gal A) activity is absent or severely reduced and disease manifestations have an early onset that can affect multiple organs. In contrast, in later-onset Fabry disease, patients have residual α-Gal A activity and clinical features are primarily confined to the heart. Individualized therapeutic goals in Fabry disease are required due to varying phenotypes and patient characteristics, and the wide spectrum of disease severity. An international group of expert physicians convened to discuss and develop practical clinical recommendations for disease- and organ-specific therapeutic goals in Fabry disease, based on expert consensus and evidence identified through a structured literature review. Biomarkers reflecting involvement of various organs in adult patients with classic Fabry disease are discussed and consensus recommendations for disease- and organ-specific therapeutic goals are provided. These consensus recommendations should support the establishment of individualized approaches to the management of patients with classic Fabry disease by considering identification, diagnosis, and initiation of disease-specific therapies before significant organ involvement, as well as routine monitoring, to reduce morbidity, optimize patient care, and improve patient health-related quality of life.

Renoprotective Effect of Agalsidase Alfa: A Long-Term Follow-Up of Patients with Fabry Disease

Fabry disease is a rare lysosomal storage disorder caused by mutations in the GLA gene, which, without treatment, can cause significant renal dysfunction. We evaluated the effects of enzyme replacement therapy with agalsidase alfa on renal decline in patients with Fabry disease using data from the Fabry Outcome Survey (FOS) registry. Male patients with Fabry disease aged >16 years at agalsidase alfa start were stratified by low (≤0.5 g/24 h) or high (>0.5 g/24 h) baseline proteinuria and by ‘classic’ or ‘non-classic’ phenotype. Overall, 193 male patients with low (n = 135) or high (n = 58) baseline proteinuria were evaluated. Compared with patients with low baseline proteinuria, those with high baseline proteinuria had a lower mean ± standard deviation baseline eGFR (89.1 ± 26.2 vs. 106.6 ± 21.8 mL/min/1.73 m2) and faster mean ± standard error eGFR decline (−3.62 ± 0.42 vs. −1.61 ± 0.28 mL/min/1.73 m2 per year; p < 0.0001). Patients with classic Fabry disease had similar rates of eGFR decline irrespective of baseline proteinuria; only one patient with non-classic Fabry disease had high baseline proteinuria, preventing meaningful comparisons between groups. In this analysis, baseline proteinuria significantly impacted the rate of eGFR decline in the overall population, suggesting that early treatment with good proteinuria control may be associated with renoprotective effects.

Metabolic Fingerprinting of Fabry Disease: Diagnostic and Prognostic Aspects

Fabry disease (FD) is an X-linked lysosomal disease due to a deficiency in the activity of the lysosomal-galactosidase A (GalA), a key enzyme in the glycosphingolipid degradation pathway. FD is a complex disease with a poor genotype–phenotype correlation. In the early stages, FD could involve the peripheral nervous system (acroparesthesias and dysautonomia) and the ski (angiokeratoma), but later kidney, heart or central nervous system impairment may significantly decrease life expectancy. The advent of omics technologies offers the possibility of a global, integrated and systemic approach well-suited for the exploration of this complex disease. In this narrative review, we will focus on the main metabolomic studies, which have underscored the importance of detecting biomarkers for a diagnostic and prognostic purpose in FD. These investigations are potentially useful to explain the wide clinical, biochemical and molecular heterogeneity found in FD patients. Moreover, the quantitative mass spectrometry methods developed to evaluate concentrations of these biomarkers in urine and plasma will be described. Finally, the complex metabolic biomarker profile depicted in FD patients will be reported, which varies according to gender, types of mutations, and therapeutic treatment.

Rare Metabolic and Endocrine Diseases with Cardiovascular Involvement: Insights from Cardiovascular Magnetic Resonance - A Review

The identification of rare diseases with cardiovascular involvement poses significant diagnostic challenges due to the rarity of the diseases, but also due to the lack of knowledge and expertise. Most of them remain underrecognized and undiagnosed, leading to clinical mismanagement and affecting the patients' prognosis, as these diseases are per definition life-threatening or chronic debilitating. This article reviews the cardiovascular involvement of the most well-known rare metabolic and endocrine diseases and their diagnostic approach through the lens of cardiovascular magnetic resonance (CMR) imaging and its prognostic role, highlighting its fundamental value compared to other imaging modalities.

Early start of enzyme replacement therapy in pediatric male patients with classical Fabry disease is associated with attenuated disease progression

BACKGROUND

Enzyme replacement therapy (ERT) slows disease progression of Fabry disease (FD), especially when initiated before the onset of irreversible organ damage. However, with the clinically asymptomatic progression of renal, cardiac and cerebral disease manifestations spanning decades, optimal timing of ERT initiation remains unclear.

METHODS

In this cross-sectional retrospective study, seven male FD patients with a classical disease phenotype (cFD) who started treatment with agalsidase-beta in childhood were evaluated after 10 years of treatment (median age at evaluation 24 years, range 14-26). Cardiac imaging (echocardiography and MRI), electrophysiological and biochemical data of these patients were compared to those of untreated male cFD patients (n = 23, median age 22 years, range 13-27).

RESULTS

Albuminuria was less common and less severe in treated patients (albumin to creatinine ratio, ACR 0-8.8 mg/mmol, median 0.4) compared to untreated patients (ACR 0-248 mg/mmol, median 3.7, p = 0.02). The treated group had a lower left ventricular mass, measured using echocardiography (median 80 g/m² versus 94 g/m², p = 0.02) and MRI (median 53 g/m² versus 68 g/m², p = 0.02). Myocardial fibrosis was absent in all included patients. eGFR was normal in all treated patients whereas 7/23 (30%) of untreated patients had abnormal eGFR. Cerebral manifestations did not differ.

CONCLUSIONS

Start of treatment with ERT before age 16, in male cFD patients is associated with reduced occurrence of renal and cardiac manifestations of FD, as assessed by intermediate endpoints. Confirmation that this approach delays or even prevents renal failure and cardiac events requires another decade of follow-up.

Clinical Characteristics, Renal Involvement, and Therapeutic Options of Pediatric Patients With Fabry Disease

Inherited renal diseases represent 20% of the causes of end-stage renal diseases. Fabry disease, an X-linked lysosomal storage disorder, results from α-galactosidase A deficient or absent activity followed by globotriaosylceramide (Gb3) accumulation and multiorgan involvement. In Fabry disease, kidney involvement starts early, during intrauterine life by the Gb3 deposition. Even if chronic kidney disease (CKD) is discovered later in adult life in Fabry disease patients, a decline in glomerular filtration rate (GFR) can occur during adolescence. The first clinical sign of kidney involvement is represented by albuminuria. So, early and close monitoring of kidneys function is required: albuminuria and proteinuria, urinary albumin-to-creatinine ratio, serum creatinine, or cystatin C to estimate GFR, while urinary sediment with phase-contrast microscopy under polarized light may be useful in those cases where leucocyte α-Gal A activity and GLA genotyping are not available. Children with Fabry disease and kidney involvement should receive enzyme replacement therapy and nephroprotective drugs (angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) to prevent or slow the progressive loss of kidney functions. Early diagnosis of Fabry disease is important as enzyme replacement therapy reduces symptoms, improves clinical features and biochemical markers, and the quality of life. More importantly, early treatment could slow or stop progressive organ damage in later life.

Diagnosis and Management of Cardiovascular Involvement in Fabry Disease

Fabry disease (FD, OMIM 301500) is an X-linked lysosomal storage disease caused by pathogenic variants in the GLA gene. Cardiac involvement is common in FD and is responsible for impaired quality of life and premature death. The classic cardiac involvement is a nonobstructive form of hypertrophic cardiomyopathy, usually manifesting as concentric left ventricular hypertrophy, with subsequent arrhythmogenic intramural fibrosis. Treatment of patients with FD should be directed to prevent the disease progression to irreversible organ damage and organ failure. The aim of this review is to describe the current state of knowledge regarding cardiovascular involvement in FD, focusing on clinical and instrumental features, cardiovascular management, and targeted therapy.

Predictors of outcome in a Spanish cohort of patients with Fabry disease on enzyme replacement therapy

Fabry disease may be treated by enzyme replacement therapy (ERT), but the impact of chronic kidney disease (CKD) on the response to therapy remains unclear. The aim of the present study was to analyse the incidence and predictors of clinical events in patients on ERT.

STUDY DESIGN

Multicentre retrospective observational analysis of patients diagnosed and treated with ERT for Fabry disease. The primary outcome was the first renal, neurological or cardiological events or death during a follow-up of 60 months (24-120).

RESULTS

In 69 patients (42 males, 27 females, mean age 44.6±13.7 years), at the end of follow-up, eGFR and the left ventricular septum thickness remained stable and the urinary albumin: creatinine ratio tended to decrease, but this decrease only approached significance in patients on agalsidase-beta (242-128mg/g (p=0.05). At the end of follow-up, 21 (30%) patients had suffered an incident clinical event: 6 renal, 2 neurological and 13 cardiological (including 3 deaths). Events were more frequent in patients with baseline eGFR≤60ml/min/1.73m² (log Rank 12.423, p=0.001), and this remained significant even after excluding incident renal events (log Rank 4.086, p=0.043) and in males and in females. Lower baseline eGFR was associated with a 3- to 7-fold increase the risk of clinical events in different Cox models.

CONCLUSIONS

GFR at the initiation of ERT is the main predictor of clinical events, both in males and in females, suggesting that start of ERT prior to the development of CKD is associated with better outcomes.

Parsing Fabry Disease Metabolic Plasticity Using Metabolomics

Background: Fabry disease (FD) is an X-linked lysosomal disease due to a deficiency in the activity of the lysosomal α-galactosidase A (GalA), a key enzyme in the glycosphingolipid degradation pathway. FD is a complex disease with a poor genotype–phenotype correlation. FD could involve kidney, heart or central nervous system impairment that significantly decreases life expectancy. The advent of omics technologies offers the possibility of a global, integrated and systemic approach well-suited for the exploration of this complex disease. Materials and Methods: Sixty-six plasmas of FD patients from the French Fabry cohort (FFABRY) and 60 control plasmas were analyzed using liquid chromatography and mass spectrometry-based targeted metabolomics (188 metabolites) along with the determination of LysoGb3 concentration and GalA enzymatic activity. Conventional univariate analyses as well as systems biology and machine learning methods were used. Results: The analysis allowed for the identification of discriminating metabolic profiles that unambiguously separate FD patients from control subjects. The analysis identified 86 metabolites that are differentially expressed, including 62 Glycerophospholipids, 8 Acylcarnitines, 6 Sphingomyelins, 5 Aminoacids and 5 Biogenic Amines. Thirteen consensus metabolites were identified through network-based analysis, including 1 biogenic amine, 2 lysophosphatidylcholines and 10 glycerophospholipids. A predictive model using these metabolites showed an AUC-ROC of 0.992 (CI: 0.965–1.000). Conclusion: These results highlight deep metabolic remodeling in FD and confirm the potential of omics-based approaches in lysosomal diseases to reveal clinical and biological associations to generate pathophysiological hypotheses.

Role of serial cardiac 18F-FDG PET-MRI in Anderson-Fabry disease: a pilot study

Aim

We investigated the value of serial cardiac ¹⁸F-FDG PET-MRI in Anderson–Fabry disease (AFD) and the potential relationship of imaging results with FASTEX score.

Methods and results

Thirteen AFD patients underwent cardiac ¹⁸F-FDG PET-MRI at baseline and follow-up. Coefficient of variation (COV) of FDG uptake and FASTEX score were assessed. At baseline, 9 patients were enzyme replacement therapy (ERT) naïve and 4 patients were under treatment. Two patients presented a FASTEX score of 0 indicating stable disease and did not show any imaging abnormality at baseline and follow-up PET-MRI. Eleven patients had a FASTEX score > 20% indicating disease worsening. Four of these patients without late gadolinium enhancement (LGE) and with normal COV at baseline and follow-up had a FASTEX score of 35%. Three patients without LGE and with abnormal COV at baseline and follow-up had a FASTEX score ranging from 30 to 70%. Three patients with LGE and abnormal COV at baseline and follow-up had a FASTEX score between 35 and 75%. Finally, one patient with LGE and normal COV had a FASTEX score of 100%. Of the 12 patients on ERT at follow-up, FASTEX score was significantly higher in those 4 showing irreversible cardiac injury at baseline compared to 8 with negative LGE (66 ± 24 vs. 32 ± 21, p = 0.03).

Conclusion

¹⁸F-FDG PET-MRI may be effective to monitor cardiac involvement in AFD.

X Chromosome Inactivation in Carriers of Fabry Disease: Review and Meta-Analysis

Anderson-Fabry disease is an X-linked inborn error of glycosphingolipid catabolism caused by a deficiency of α-galactosidase A. The incidence ranges between 1: 40,000 and 1:117,000 of live male births. In Italy, an estimate of incidence is available only for the north-western Italy, where it is of approximately 1:4000. Clinical symptoms include angiokeratomas, corneal dystrophy, and neurological, cardiac and kidney involvement. The prevalence of symptomatic female carriers is about 70%, and in some cases, they can exhibit a severe phenotype. Previous studies suggest a correlation between skewed X chromosome inactivation and symptoms in carriers of X-linked disease, including Fabry disease. In this review, we briefly summarize the disease, focusing on the clinical symptoms of carriers and analysis of the studies so far published in regards to X chromosome inactivation pattern, and manifesting Fabry carriers. Out of 151 records identified, only five reported the correlation between the analysis of XCI in leukocytes and the related phenotype in Fabry carriers, in particular evaluating the Mainz Severity Score Index or cardiac involvement. The meta-analysis did not show any correlation between MSSI or cardiac involvement and skewed XCI, likely because the analysis of XCI in leukocytes is not useful for predicting the phenotype in Fabry carriers.

Defective lysosomal storage in Fabry disease modifies mitochondrial structure, metabolism and turnover in renal epithelial cells

Fabry disease (FD) is an X-linked lysosomal storage disorder. Deficiency of the lysosomal enzyme alpha-galactosidase (GLA) leads to accumulation of potentially toxic globotriaosylceramide (Gb3) on a multisystem level. Cardiac and cerebrovascular abnormalities as well as progressive renal failure are severe, life-threatening long-term complications. The complete pathophysiology of chronic kidney disease (CKD) in FD and the role of tubular involvement for its progression are unclear. We established human renal tubular epithelial cell lines from the urine of male FD patients and male controls. The renal tubular system is rich in mitochondria and involved in transport processes at high-energy costs. Our studies revealed fragmented mitochondria with disrupted cristae structure in FD patient cells. Oxidative stress levels were elevated and oxidative phosphorylation was upregulated in FD pointing at enhanced energetic needs. Mitochondrial homeostasis and energy metabolism revealed major changes as evidenced by differences in mitochondrial number, energy production and fuel consumption. The changes were accompanied by activation of the autophagy machinery in FD. Sirtuin1, an important sensor of (renal) metabolic stress and modifier of different defense pathways, was highly expressed in FD. Our data show that lysosomal FD impairs mitochondrial function and results in severe disturbance of mitochondrial energy metabolism in renal cells. This insight on a tissue-specific level points to new therapeutic targets which might enhance treatment efficacy.

Human α-Galactosidase A Mutants: Priceless Tools to Develop Novel Therapies for Fabry Disease

Fabry disease (FD) is a lysosomal storage disease caused by mutations in the gene for the α-galactosidase A (GLA) enzyme. The absence of the enzyme or its activity results in the accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3), in different tissues, leading to a wide range of clinical manifestations. More than 1000 natural variants have been described in the GLA gene, most of them affecting proper protein folding and enzymatic activity. Currently, FD is treated by enzyme replacement therapy (ERT) or pharmacological chaperone therapy (PCT). However, as both approaches show specific drawbacks, new strategies (such as new forms of ERT, organ/cell transplant, substrate reduction therapy, or gene therapy) are under extensive study. In this review, we summarize GLA mutants described so far and discuss their putative application for the development of novel drugs for the treatment of FD. Unfavorable mutants with lower activities and stabilities than wild-type enzymes could serve as tools for the development of new pharmacological chaperones. On the other hand, GLA mutants showing improved enzymatic activity have been identified and produced in vitro. Such mutants could overcome several complications associated with current ERT, as lower-dose infusions of these mutants could achieve a therapeutic effect equivalent to that of the wild-type enzyme.

Enzyme Replacement Therapy for Genetic Disorders Associated with Enzyme Deficiency

Mutations in human genes might lead to loss of functional proteins, causing diseases. Among these genetic disorders, a large class is associated with the deficiency in metabolic enzymes, resulting in both an increase in the concentration of substrates and a loss in the metabolites produced by the catalyzed reactions. The identification of therapeutic actions based on small molecules represents a challenge to medicinal chemists because the target is missing. Alternative approaches are biology-based, ranging from gene and stem cell therapy, CRISPR/Cas9 technology, distinct types of RNAs, and enzyme replacement therapy (ERT). This review will focus on the latter approach that since the 1990s has been successfully applied to cure many rare diseases, most of them being lysosomal storage diseases or metabolic diseases. So far, a dozen enzymes have been approved by FDA/EMA for lysosome storage disorders and only a few for metabolic diseases. Enzymes for replacement therapy are mainly produced in mammalian cells and some in plant cells and yeasts and are further processed to obtain active, highly bioavailable, less degradable products. Issues still under investigation for the increase in ERT efficacy are the optimization of enzymes interaction with cell membrane and internalization, the reduction in immunogenicity, and the overcoming of blood-brain barrier limitations when neuronal cells need to be targeted. Overall, ERT has demonstrated its efficacy and safety in the treatment of many genetic rare diseases, both saving newborn lives and improving patients' life quality, and represents a very successful example of targeted biologics.

[Chaperone molecules: The example of Fabry disease]

Fabry disease is due to mutations in the GLA gene that cause a deficiency of the activity of the lysosomal enzyme alpha-galactosidase A (α-gal A) resulting in intra-tissue accumulation of globotriaosylceramide. Recently, a novel therapeutic approach based on the pharmacological chaperone migalastat has been developed. It binds, in a specific and reversible manner, to the catalytic site of α-gal A mutants, to prevent their degradation by the quality control system of the endoplasmic reticulum and allow them to catabolize globotriaosylceramide in the lysosomes. This treatment concerns approximately 35% of the GLA gene mutations recognized as sensitive to migalastat according to an in vitro pharmacogenetic test. Two pivotal Phase III studies, FACETS: migalastat vs. placebo and ATTRACT: migalastat vs. enzyme replacement therapy analyzed the in vivo effects of migalastat. Despite some methodological limitations, promising results were found. Migalastat seems to be more effective than enzyme replacement therapy in reducing left ventricular mass index in case of cardiac hypertrophy and has comparable renal effects. This oral treatment is the first personalized treatment, based on the genetic profile of Fabry patients and opens a new era in the management of conformational diseases.

Fabry disease: what the cardiologist should consider in non-cardiac screening, diagnosis, and management-narrative review

Fabry disease (FD) is a rare X chromosomally transmitted lysosomal storage disorders with an absence or deficiency of the enzyme alpha-galactosidase. The deposition of globotriaosylceramide (Gb3) may cause damage to all organs, particularly brain, heart and kidney. While acroparaesthesia, hypo- or anhydrosis and diarrhoea are the main symptoms in childhood, cardiac involvement with left ventricular hypertrophy (LVH), renal insufficiency, diffuse pain attacks and apoplexy are the main symptoms in adulthood. Regular examinations are necessary to record organ involvement and its progression. A major challenge is therefore to make a diagnosis at an early disease stage. This is the only way that treatment can be started if there is an indication. If FD is suspected, alpha-galactosidase should be tested in male patients and genetic testing should be performed in females to confirm the diagnosis. Since 2001, enzyme replacement therapy (ERT) has been available as a causal therapy. In 2016, chaperone therapy with the drug Migalastat was approved in the European Union, which leads to stabilisation of the defective alpha-galactosidase. Studies on gene therapy to cure FD in phase I/II. This review summarizes which patient should be screened, how to confirm the diagnosis and which examinations should be performed in FD patients during the course of the disease.

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.

Predictors of outcome in a Spanish cohort of patients with Fabry disease on enzyme replacement therapy

Fabry disease may be treated by enzyme replacement therapy (ERT), but the impact of chronic kidney disease (CKD) on the response to therapy remains unclear. The aim of the present study was to analyse the incidence and predictors of clinical events in patients on ERT.

STUDY DESIGN

Multicentre retrospective observational analysis of patients diagnosed and treated with ERT for Fabry disease. The primary outcome was the first renal, neurological or cardiological events or death during a follow-up of 60 months (24-120).

RESULTS

In 69 patients (42 males, 27 females, mean age 44.6±13.7 years), at the end of follow-up, eGFR and the left ventricular septum thickness remained stable and the urinary albumin: creatinine ratio tended to decrease, but this decrease only approached significance in patients on agalsidase-beta (242-128mg/g (p=0.05). At the end of follow-up, 21 (30%) patients had suffered an incident clinical event: 6 renal, 2 neurological and 13 cardiological (including 3 deaths). Events were more frequent in patients with baseline eGFR≤60ml/min/1.73m2 (log Rank 12.423, p=0.001), and this remained significant even after excluding incident renal events (log Rank 4.086, p=0.043) and in males and in females. Lower baseline eGFR was associated with a 3- to 7-fold increase the risk of clinical events in different Cox models.

CONCLUSIONS

GFR at the initiation of ERT is the main predictor of clinical events, both in males and in females, suggesting that start of ERT prior to the development of CKD is associated with better outcomes.

Quantification of myocardial deformation in patients with Fabry disease by cardiovascular magnetic resonance feature tracking imaging

Background

Cardiac involvement is a major contributor of morbidity and mortality in Fabry disease (FD). Early detection and accurate evaluation of the disease progression is important in management. Cardiovascular magnetic resonance (CMR) derived feature fracking (FT) is a validated quantitative method of assessing myocardial deformation which may reflect early changes of myocardial function and track disease severity. We sought to evaluate the utility of CMR-FT as a measure of myocardial dysfunction in FD.

Methods

Twenty FD patients (12 males, 40.8±14.9 years) and 20 age and sex matched healthy controls (10 males, 40.5±7.2 years) were prospectively enrolled. Subjects underwent CMR including cine, pre-/post-contrast T1 mapping and late gadolinium enhancement (LGE). FD patients were divided into three groups; group 1: patients without left ventricular hypertrophy (LVH) and LGE negative; group 2: patients with LVH positive, LGE either positive or negative; group 3: patients with LGE positive, LV wall thinning and heart failure. FT derived strain indices were measured and its associations with other processes were investigated.

Results

In FD patients, 14 (70%) had LVH and 4 (20%) had LGE. Compared with normal controls, LV global longitudinal strain (GLS) were reduced significantly in all three Fabry groups (all P<0.05), global circumferential strain (GCS) were reduced only in group 2 and group 3 (P<0.05). Among three FD groups, there were significant differences of LV GLS, GCS, native T1 value and extracellular volume fraction (ECV) (all P<0.01), group 1 had mild LV strain indices impairment, group 3 had the most severe LV strain indices. When compared between FD subgroups, GLS and GCS showed significant difference between each two groups (all P<0.05). There were weak correlations between the LV functional parameters (ejection fraction, LV mass index), maximal wall thickness, T1 mapping indices (native T1, ECV) and LV strain indices. The strongest relation was between global longitudinal early diastolic strain rate and native T1 value (r=0.783, P<0.01).

Conclusions

CMR strain imaging identifies myocardial deformation in FD in different stages. Strain imaging can track disease severity and may be an alternative method for follow-up of FD patients.

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

PURPOSE

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

METHODS

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

FINDINGS

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

IMPLICATIONS

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

Early indicators of disease progression in Fabry disease that may indicate the need for disease-specific treatment initiation: findings from the opinion-based PREDICT-FD modified Delphi consensus initiative

OBJECTIVES

The PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease (PREDICT-FD) initiative aimed to reach consensus among a panel of global experts on early indicators of disease progression that may justify FD-specific treatment initiation.

DESIGN AND SETTING

Anonymous feedback from panellists via online questionnaires was analysed using a modified Delphi consensus technique. Questionnaires and data were managed by an independent administrator directed by two non-voting cochairs. First, possible early indicators of renal, cardiac and central/peripheral nervous system (CNS/PNS) damage, and other disease and patient-reported indicators assessable in routine clinical practice were compiled by the cochairs and administrator from panellists' free-text responses. Second, the panel scored indicators for importance (5-point scale: 1=not important; 5=extremely important); indicators scoring ≥3 among >75% of panellists were then rated for agreement (5-point scale: 1=strongly disagree; 5=strongly agree). Indicators awarded an agreement score ≥4 by >67% of panellists achieved consensus. Finally, any panel-proposed refinements to consensus indicator definitions were adopted if >75% of panellists agreed.

RESULTS

A panel of 21 expert clinicians from 15 countries provided information from which 83 possible current indicators of damage (kidney, 15; cardiac, 15; CNS/PNS, 13; other, 16; patient reported, 24) were compiled. Of 45 indicators meeting the importance criteria, consensus was reached for 29 and consolidated as 27 indicators (kidney, 6; cardiac, 10; CNS/PNS, 2; other, 6; patient reported, 3) including: (kidney) elevated albumin:creatinine ratio, histological damage, microalbuminuria; (cardiac) markers of early systolic/diastolic dysfunction, elevated serum cardiac troponin; (CNS/PNS) neuropathic pain, gastrointestinal symptoms suggestive of gastrointestinal neuropathy; (other) pain in extremities/neuropathy, angiokeratoma; (patient-reported) febrile crises, progression of symptoms/signs. Panellists revised and approved proposed chronologies of when the consensus indicators manifest. The panel response rate was >95% at all stages.

CONCLUSIONS

PREDICT-FD captured global opinion regarding current clinical indicators that could prompt FD-specific treatment initiation earlier than is currently practised.

Detection of novel Fabry disease-associated pathogenic variants in Japanese patients by newborn and high-risk screening

Background

In Japan, newborn and high‐risk screening for Fabry disease (FD), an inherited X‐linked disorder caused by GLA mutations, using dried blood spots was initiated in 2006. In newborn screening, 599,711 newborns were screened by December 2018, and 57 newborns from 54 families with 26 FD‐associated variants were detected. In high‐risk screening, 18,235 individuals who had symptoms and/or a family history of FD were screened by March 2019, and 236 individuals from 143 families with 101 FD‐associated variants were detected. Totally 3, 116 variants were detected; 41 of these were not registered in Fabry‐database.org or ClinVar and 33 were definitely novel. Herein, we report the clinical outcomes and discuss the pathogenicity of the 41 variants.

Methods

We traced nine newborns and 46 individuals with the 33 novel variants, and nine newborns and 10 individuals with eight other variants not registered in the FD database, and analyzed the information on symptoms, treatments, and outcomes.

Results

Thirty‐eight of the 46 individuals with the 33 novel variants showed symptoms and received enzyme‐replacement therapy and/or chaperone treatment.

Conclusion

Delayed diagnosis should be avoided in patients with FD. Our results will help clinicians diagnose FD and determine the appropriate treatment for patients with these variants.

Nine newborns and 46 individuals with 33 novel variants, and nine newborns and 10 individuals with eight other variants not registered in the FD database were traced and the information on symptoms, treatments, and outcomes was analyzed. Thirty‐eight of 46 individuals with 33 novel variants had symptoms and received enzyme replacement therapy and/or chaperone treatment.

Assessment of plasma lyso-Gb3 for clinical monitoring of treatment response in migalastat-treated patients with Fabry disease

PURPOSE

To assess the utility of globotriaosylsphingosine (lyso-Gb₃) for clinical monitoring of treatment response in patients with Fabry disease receiving migalastat.

METHODS

A post hoc analysis evaluated data from 97 treatment-naive and enzyme replacement therapy (ERT)-experienced patients with migalastat-amenable GLA variants from FACETS (NCT00925301) and ATTRACT (NCT01218659) and subsequent open-label extension studies. The relationship between plasma lyso-Gb₃ and measures of Fabry disease progression (left ventricular mass index [LVMi], estimated glomerular filtration rate [eGFR], and pain) and the relationship between lyso-Gb₃ and incidence of Fabry-associated clinical events (FACEs) were assessed in both groups. The relationship between changes in lyso-Gb₃ and kidney interstitial capillary (KIC) globotriaosylceramide (Gb₃) inclusions was assessed in treatment-naive patients.

RESULTS

No significant correlations were identified between changes in lyso-Gb₃ and changes in LVMi, eGFR, or pain. Neither baseline lyso-Gb₃ levels nor the rate of change in lyso-Gb₃ levels during treatment predicted FACE occurrences in all patients or those receiving migalastat for ≥24 months. Changes in lyso-Gb₃ correlated with changes in KIC Gb₃ inclusions in treatment-naive patients.

CONCLUSIONS

Although used as a pharmacodynamic biomarker in research and clinical studies, plasma lyso-Gb₃ may not be a suitable biomarker for monitoring treatment response in migalastat-treated patients.

Therapeutic advances in Fabry disease: The future awaits

Fabry disease (FD) is an X-linked disorder caused by mutations in GLA gene responsible for coding of the lysosomal enzyme alpha-galactosidase A(α-GAL). The resultant accumulation of globotriaosylceramide (Gb-3) leads to multisystemic disease including progressive chronic kidney disease, hypertrophic cardiomyopathy, stroke, angiokeratomas and corneal whorls. Current treatments include enzyme replacement therapy (ERT), along with recent advent of chaperone therapy. ERT has not shown to have dramatic improvement in outcomes for all organ systems, with benefit mostly seen in kidney disease and reduction in left ventricular hypertrophy. ERT, however, is associated with formation of anti-drug antibodies and requirement of long-term venous access, while chaperone therapy can only be used in amenable mutations. A multitude of therapies are now under investigation in various phases of clinical trials. These include pegylated form of α-GAL (pegunigalsidase alpha), gene therapy (both in-vivo and ex-vivo methods), mRNA therapy (inducing production of α-GAL) and substrate reduction therapy (inhibitors of glucosylceramide synthase leading to reduction of Gb-3). This review encapsulates literature pertaining to current and investigational therapies for FD.

Long-term efficacy and safety of migalastat treatment in Fabry disease: 30-month results from the open-label extension of the randomized, phase 3 ATTRACT study

Results from the 18-month randomized treatment period of the phase 3 ATTRACT study demonstrated the efficacy and safety of oral migalastat compared with enzyme replacement therapy (ERT) in patients with Fabry disease who previously received ERT. Here, we report data from the subsequent 12-month, migalastat-only, open-label extension (OLE) period. ATTRACT (Study AT1001-012; NCT01218659) was a randomized, open-label, active-controlled study in patients aged 16-74 years with Fabry disease, an amenable GLA variant, and an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m². During the OLE, patients who received migalastat 150 mg every other day (QOD) during the randomized period continued receiving migalastat (Group 1 [MM]); patients who received ERT every other week discontinued ERT and started migalastat treatment (Group 2 [EM]). Outcome measures included eGFR, left ventricular mass index (LVMi), composite clinical outcome (renal, cardiac or cerebrovascular events), and safety. Forty-six patients who completed the randomized treatment period continued into the OLE (Group 1 [MM], n = 31; Group 2 [EM], n = 15). eGFR remained stable in both treatment groups. LVMi decreased from baseline at month 30 in Group 1 (MM) in patients with left ventricular hypertrophy at baseline. Only 10% of patients experienced a new composite clinical event with migalastat treatment during the OLE. No new safety concerns were reported. In conclusion, in patients with Fabry disease and amenable GLA variants, migalastat 150 mg QOD was well tolerated and demonstrated durable, long-term stability of renal function and reduction in LVMi.

Developments in the treatment of Fabry disease

Enzyme replacement therapy (ERT) with recombinant α-galactosidase A (r-αGAL A) for the treatment of Fabry disease has been available for over 15 years. Long-term treatment may slow down disease progression, but cardiac, renal, and cerebral complications still develop in most patients. In addition, lifelong intravenous treatment is burdensome. Therefore, several new treatment approaches have been explored over the past decade. Chaperone therapy (Migalastat; 1-deoxygalactonojirimycin) is the only other currently approved therapy for Fabry disease. This oral small molecule aims to improve enzyme activity of mutated α-galactosidase A and can only be used in patients with specific mutations. Treatments currently under evaluation in (pre)clinical trials are second generation enzyme replacement therapies (Pegunigalsidase-alfa, Moss-aGal), substrate reduction therapies (Venglustat and Lucerastat), mRNA- and gene-based therapy. This review summarises the knowledge on currently available and potential future options for the treatment of Fabry disease.

Predicting the Development of Anti-Drug Antibodies against Recombinant alpha-Galactosidase A in Male Patients with Classical Fabry Disease

Fabry Disease (FD) is a rare, X-linked, lysosomal storage disease that mainly causes renal, cardiac and cerebral complications. Enzyme replacement therapy (ERT) with recombinant alpha-galactosidase A is available, but approximately 50% of male patients with classical FD develop inhibiting anti-drug antibodies (iADAs) that lead to reduced biochemical responses and an accelerated loss of renal function. Once immunization has occurred, iADAs tend to persist and tolerization is hard to achieve. Here we developed a pre-treatment prediction model for iADA development in FD using existing data from 120 classical male FD patients from three European centers, treated with ERT. We found that nonsense and frameshift mutations in the α-galactosidase A gene (p = 0.05), higher plasma lysoGb3 at baseline (p < 0.001) and agalsidase beta as first treatment (p = 0.006) were significantly associated with iADA development. Prediction performance of a Random Forest model, using multiple variables (AUC-ROC: 0.77) was compared to a logistic regression (LR) model using the three significantly associated variables (AUC-ROC: 0.77). The LR model can be used to determine iADA risk in individual FD patients prior to treatment initiation. This helps to determine in which patients adjusted treatment and/or immunomodulatory regimes may be considered to minimize iADA development risk.

Switch from enzyme replacement therapy to oral chaperone migalastat for treating fabry disease: real-life data

The treatment options for Fabry disease (FD) are enzyme replacement therapy (ERT) with agalsidase alfa or beta, and the oral pharmacological chaperone migalastat. Since few data are available on the effects of switching from ERT to migalastat, we performed a single-center observational study on seven male Fabry patients (18-66 years) to assess the effects of the switch on renal, cardiac, and neurologic function, health status, pain, lyso-Gb3, α-Gal A activity and adverse effects. Data were retrospectively collected at time of diagnosis of FD (baseline, T0), and after 12 months of ERT (T1), and prospectively after 1 year of therapy with migalastat (T2). No patient died or reported renal, cardiac, or cerebrovascular events during the study period. The predefined measures for cardiac, renal and neurologic function, and FD-related symptoms and questionnaires were stable between baseline and the switch, and remained unchanged with migalastat. However, a significant improvement was observed in left ventricular mass index from baseline to T2 (p = 0.016), with a significative difference between the treatments (p = 0.028), and in median proteinuria from T2 vs T1 (p = 0.048). Moreover, scores of the BPI improved from baseline to T1, and remained stable with migalastat. Plasma lyso-Gb3 levels significantly decreased from baseline to T1 (P = 0.007) and T2 (P = 0.003), while did not significantly differ between the two treatments. α-Gal A activity increased from T0 to T2 (p < 0.0001). The frequency of adverse effects under migalastat and ERT was comparable (28% for both drugs). In conclusion, switching from ERT to migalastat is valid, safe and well tolerated.

Left Ventricular Mass and Wall Thickness Measurements Using Echocardiography and Cardiac MRI in Patients with Fabry Disease: Clinical Significance of Discrepant Findings

Purpose

To compare transthoracic echocardiography (TTE) and cardiac MRI measurements of left ventricular mass (LVM) and maximum wall thickness (MWT) in patients with Fabry disease and evaluate the clinical significance of discrepancies between modalities.

Materials and Methods

Seventy-eight patients with Fabry disease (mean age, 46 years ± 14 [standard deviation]; 63% female) who underwent TTE and cardiac MRI within a 6-month interval between 2008 and 2018 were included in this retrospective cohort study. The clinical significance of measurement discrepancies was evaluated with respect to diagnosis of left ventricular hypertrophy (LVH), eligibility for disease-specific therapy, and prognosis. Statistical analysis included paired-sample t test, Cox proportional hazard models, Akaike information criterion (AIC), and intraclass correlation coefficients.

Results

LVM indexed to body surface area (LVMI) and MWT were significantly higher at TTE compared with MRI (105 g/m² ± 48 vs 78 g/m² ± 36, P < .001 and 14 mm ± 4 vs 13 mm ± 5, P = .008, respectively). LVH classification was discordant between modalities in 23 patients (29%) (P < .001). Eligibility for disease-specific therapy based on MWT was discordant between modalities in 20 patients (26%) (P < .001). LVMI assessed with MRI was a better predictor of the combined endpoint compared with LVMI assessed with TTE (AIC, 127 vs 131). Interobserver agreement for LVMI and MWT was higher for MRI (intraclass correlation coefficient, 0.951 and 0.912, respectively) compared with TTE (intraclass correlation coefficient, 0.940 and 0.871; respectively).

Conclusion

TTE overestimates LVM and MWT and has lower reproducibility compared with cardiac MRI in Fabry disease. Measurement discrepancies between modalities are clinically significant with respect to diagnosis of LVH, prognosis, and treatment decisions.© RSNA, 2020.

A Proteomics-Based Analysis Reveals Predictive Biological Patterns in Fabry Disease

Background: Fabry disease (FD) is an X-linked progressive lysosomal disease (LD) due to glycosphingolipid metabolism impairment. Currently, plasmatic globotriaosylsphingosine (LysoGb3) is used for disease diagnosis and monitoring. However, this biomarker is inconstantly increased in mild forms and in some female patients. Materials and Methods: We applied a targeted proteomic approach to explore disease-related biological patterns that might explain the disease pathophysiology. Forty proteins, involved mainly in inflammatory and angiogenesis processes, were assessed in 69 plasma samples retrieved from the French Fabry cohort (FFABRY) and from 83 healthy subjects. For predictive performance assessment, we also included other LD samples (Gaucher, Pompe and Niemann Pick C). Results: The study yielded four discriminant proteins that include three angiogenesis proteins (fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor C (VEGFC)) and one cytokine interleukin 7 (IL-7). A clear elevation of FGF2 and IL-7 concentrations was observed in FD compared to other LD samples. No correlation was observed between these proteins and globotriaosylsphingosine (LysoGb3). A significant correlation exists between IL-7 and residual enzyme activity in a non-classical phenotype. This highlights the orthogonal biological information yielded by these proteins that might help in stratifying Fabry patients. Conclusion: This work highlights the potential of using proteomics approaches in exploring FD and enhancing FD diagnosis and therapeutic monitoring performances.