Relief of gastrointestinal symptoms under enzyme replacement therapy [corrected] in patients with Fabry disease

Divergent Impact of Enzyme Replacement Therapy on Human Cardiomyocytes and Enterocytes Affected by Fabry Disease: Correlation with Mannose-6-phosphate Receptor Expression

Background: The impact of enzyme replacement therapy (ERT) on cardiomyocytes and intestinal cells, affected by Fabry disease (FD), is still unclear. Methods: Six patients with FD, including five family members with GLA mutation c.666delC and one with GLA mutation c.658C > T, manifesting cardiomyopathy and intestinal symptoms (abdominal pain, diarrhea and malabsorption) were included in the study. Clinical outcome, cardiac magnetic resonance (CMR), endomyocardial and gastro-intestinal biopsies were evaluated before and after 2 years of treatment with agalsidase-α (0.2 mg/kg every other week). Immunohistochemistry and Western blot assessments of mannose-6-phosphate receptors (IGF-II-R) on intestinal and myocardial frozen tissue were obtained at diagnosis and after 2 years of ERT. Results: After ERT left ventricular maximal wall thickness, ranging from pre (<10.5 mm) to mild (<15 mm) and moderate hypertrophy (16 mm), was not associated with significant changes at CMR. Degree of dyspnea, mean cardiomyocyte diameter and % vacuolated areas of cardiomyocytes, representing intracellular GL3, remained unmodified. In contrast, intestinal symptoms improved with disappearance of diarrhea, recovery of anemia and weight gain, correlating with near complete clearance of the enterocytes from GL3 inclusions. IGF-II-R expression was remarkably higher even at histochemistry in intestinal tissue compared with myocardium (p < 0.001) either at baseline and after ERT, thus justifying intestinal recovery. Conclusions: Human cells affected by FD may respond differently to ERT: while cardiomyocytes retain their GL3 content after 2 years of treatment, gastro-intestinal cells show GL3 removal with recovery of function. This divergent response may be related to differences in cellular turnover, as well as tissue IGF-II-R expression.

Fabry disease - a multisystemic disease with gastrointestinal manifestations

Nonspecific gastrointestinal (GI) symptoms, such as postprandial cramping pain, diarrhea, nausea and vomiting are typical symptoms for irritable bowel syndrome or inflammatory bowel disease, but may also be the first symptoms of Fabry disease (FD). This review focus on GI manifestations in FD, by providing an overview of symptoms, a proper diagnosis, an appropriate management by FD-specific and concomitant medications and lifestyle interventions. We provide comprehensive literature-based data combined with personal experience in the management of FD patients. Since FD is rare and the clinical phenotype is heterogeneous, affected patients are often misdiagnosed. Consequently, physicians should consider FD as a possible differential diagnosis when assessing unspecific GI symptoms. Improved diagnostic tools, such as a modified GI symptom assessment scale can facilitate the diagnosis of FD in patients with GI symptoms of unknown cause and thus enable the timely initiation of a disease-specific therapy. Expansive intravenous enzyme replacement therapy with α-galactosidase A or oral chaperone therapy for patients with amenable mutations improve the disease burden including GI symptoms, but a timely start of therapy is crucial for the prognosis. A special diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) or pro- and prebiotics might improve FD-typical GI symptoms. Furthermore, preliminary success was reported with the oral administration of α-galactosidase A. In addition to a timely initiation of FD-specific therapy, affected patients with GI symptoms might benefit from a FODMAP-low diet, pro- and prebiotics and/or low-cost oral substitution with AGAL to support digestion and reduce dysbiosis.

Fabry disease pain: patient and preclinical parallels

ABSTRACT

Severe neuropathic pain is a hallmark of Fabry disease, a genetic disorder caused by a deficiency in lysosomal α-galactosidase A. Pain experienced by these patients significantly impacts their quality of life and ability to perform everyday tasks. Patients with Fabry disease suffer from peripheral neuropathy, sensory abnormalities, acute pain crises, and lifelong ongoing pain. Although treatment of pain through medication and enzyme replacement therapy exists, pain persists in many of these patients. Some has been learned in the past decades regarding clinical manifestations of pain in Fabry disease and the pathological effects of α-galactosidase A insufficiency in neurons. Still, it is unclear how pain and sensory abnormalities arise in patients with Fabry disease and how these can be targeted with therapeutics. Our knowledge is limited in part due to the lack of adequate preclinical models to study the disease. This review will detail the types of pain, sensory abnormalities, influence of demographics on pain, and current strategies to treat pain experienced by patients with Fabry disease. In addition, we discuss the current knowledge of Fabry pain pathogenesis and which aspects of the disease preclinical models accurately recapitulate. Understanding the commonalities and divergences between humans and preclinical models can be used to further interrogate mechanisms causing the pain and sensory abnormalities as well as advance development of the next generation of therapeutics to treat pain in patients with Fabry disease.

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 Patient-Reported Outcome-GastroIntestinal (FABPRO-GI): A new Fabry disease-specific gastrointestinal outcomes instrument

PURPOSE

Fabry disease is a rare multisystemic disorder caused by functional deficiency of the lysosomal enzyme alpha-galactosidase A. Gastrointestinal (GI) signs and symptoms are among the earliest clinical manifestations in patients with Fabry disease but are often nonspecific, misdiagnosed, and untreated. No instruments have been developed specifically to assess GI signs and symptoms in Fabry disease. The FABry disease Patient-Reported Outcome-GastroIntestinal (FABPRO-GI) was developed to address this unmet need and is intended for use in clinical trials (24-h FABPRO-GI) and real-world settings (7-day FABPRO-GI).

METHODS

Findings from a literature review, expert advisory meetings, and patient concept elicitation interviews (CEIs) were summarized into conceptual models. These conceptual models were used to develop preliminary versions of the 24-h and 7-day FABPRO-GI. Cognitive debriefing interviews (CDIs) were conducted with additional patients to assess content validity, including understandability, relevance, and comprehensiveness of the preliminary versions of the 24-h and 7-day FABPRO-GI.

RESULTS

Literature review (n = 17 articles), expert advisory meetings (n = 5), and patient CEIs (n = 17) identified mostly overlapping Fabry disease-related GI signs and symptoms, including abdominal cramps, bloating, and diarrhea, and informed development of the preliminary 24-h and 7-day FABPRO-GI. CDIs (n = 15) provided evidence of content validity and informed revisions of the 24-h and 7-day FABPRO-GI.

CONCLUSION

With evidence of content validity, the 24-h and 7-day FABPRO-GI are the first Fabry disease-specific patient-reported outcomes to assess GI signs and symptoms in patients with Fabry disease with potential for use in clinical trials and real-world settings, respectively.

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.

Pegunigalsidase alfa, a novel PEGylated enzyme replacement therapy for Fabry disease, provides sustained plasma concentrations and favorable pharmacodynamics: A 1-year Phase 1/2 clinical trial

Pegunigalsidase alfa, a novel PEGylated, covalently crosslinked form of α-galactosidase A developed as enzyme replacement therapy (ERT) for Fabry disease (FD), was designed to increase plasma half-life and reduce immunogenicity, thereby enhancing efficacy compared with available products. Symptomatic adults with FD participated in this open-label, 3-month dose-ranging study, followed by a 9-month extension. Three cohorts were enrolled in a stepwise manner, each receiving increased doses of pegunigalsidase alfa: 0.2, 1.0, 2.0 mg/kg, via intravenous infusion every other week. Pharmacokinetic analysis occurred on Day 1 and Months 3, 6, and 12. Kidney biopsies at baseline and Month 6 assessed peritubular capillary globotriaosylceramide (Gb3) content. Renal function, cardiac parameters, and other clinical endpoints were assessed throughout. Treatment-emergent adverse events (AEs) and presence of immunoglobulin G (IgG) antidrug antibodies (ADAs) were assessed. Sixteen patients completed 1 year's treatment. Mean terminal plasma half-life (each cohort) ranged from 53 to 121 hours. All 11 male and 1 of 7 female patients presented with classic FD phenotype, in whom renal peritubular capillary Gb3 inclusions were reduced by 84%. Mean estimated glomerular filtration rate was 111 mL/min/1.73 m² at baseline, remaining stable throughout treatment. Three patients developed treatment-induced IgG ADAs; following 1 year's treatment, all became ADA-negative. Nearly all treatment-emergent AEs were mild or moderate. One patient withdrew from the study following a serious related AE. Pegunigalsidase alfa may represent an advance in ERT for FD, based on its unique pharmacokinetics and apparent low immunogenicity.

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.

Major Organic Involvement in Women with Fabry Disease in Argentina

Fabry disease (FD) is an X-linked lysosomal storage disorder resulting from the deficiency or absence of the alpha galactosidase A enzyme. Organic involvement in men is well known, but in women it is controversial, partly due to the random X-chromosomes inactivation (Lyon hypothesis). The aim of this study was to describe the organic involvement in women at the time of FD diagnosis. A descriptive, cross-sectional and multicenter study was carried out. Thirty-five women with FD from three reference centers in Argentina were evaluated. The mean age of the whole group (n = 35) was 26.6 ± 16.9 years; 22 were adult (over 18) and 13 were paediatric patients. Enzymatic activity was performed in 29/35 patients, which was normal in 24/29 (82.8%). Seven different mutations of the GLA gene were found. The results showed urinary protein loss (45.7%) and decreased glomerular filtration rate (31.4%), mainly in adults. And also, cornea verticillata (56.5%), peripheral neuropathy (51.4%), cardiovascular manifestations (31.4%), hearing loss (20%), angiokeratomas (20%), central nervous system (17.1%), and gastrointestinal involvement (14.3%). Organic compromise in females with FD may be as severe as in men. This analysis has demonstrated a significant proportion of women with signs, symptoms, and major organic involvement at FD diagnosis.

Non-specific gastrointestinal features: Could it be Fabry disease?

Non-specific gastrointestinal symptoms, including pain, diarrhoea, nausea, and vomiting, can be the first symptoms of Fabry disease. They may suggest more common disorders, e.g. irritable bowel syndrome or inflammatory bowel disease. The confounding clinical presentation and rarity of Fabry disease often cause long diagnostic delays and multiple misdiagnoses. Therefore, specialists involved in the clinical evaluation of non-specific upper and lower gastrointestinal symptoms should recognize Fabry disease as a possible cause of the symptoms, and should consider Fabry disease as a possible differential diagnosis. When symptoms or family history suggest Fabry disease, in men, low alpha-galactosidase A enzyme levels, and in women, specific Fabry mutations confirm the diagnosis. In addition to symptomatic treatments, disease-specific enzyme replacement therapy with recombinant human alpha-galactosidase A enzyme or chaperone therapy (migalastat) in patients with amenable mutations can improve the disease, including gastrointestinal symptoms, and should be initiated as early as possible after Fabry disease has been confirmed; starting enzyme replacement therapy at as young an age as possible after diagnosis improves long-term clinical outcomes. Improved diagnostic tools, such as a modified gastrointestinal symptom rating scale, may facilitate diagnosing Fabry disease in patients with gastrointestinal symptoms of unknown cause and thus assure timely initiation of disease-specific treatment.

Chronic intestinal pseudo-obstruction. Did you search for lysosomal storage diseases?

Chronic intestinal pseudo-obstruction results in clinical manifestations that resemble intestinal obstruction but in the absence of any physical obstructive process. Fabry disease is an X-linked lysosomal storage disease characterized by the dysfunction of multiple systems, including significant gastrointestinal involvement. We report the occurrence of chronic intestinal pseudo-obstruction in two unrelated patients with Fabry disease and the possible explanation of a direct relation of these two disorders. In Fabry disease, gastrointestinal symptoms occur in approximately 70% of male patients, but the frequency ranges from 19% to 69% in different series. In some patients, colonic dysmotility due glycolipid deposition in autonomic plexus and ganglia can lead to the pseudo-obstruction syndrome, simulating intestinal necrosis. That is why up to this date colostomy has been performed in some cases, even for children with FD without cardiac, renal or cerebrovascular compromise. Early treatment with enzyme replacement therapy in asymptomatic or mildly symptomatic patients may be justified in order to prevent disease progression. Several studies have demonstrated that enzyme replacement therapy alleviates GI manifestations. Because of the non-specific nature of the gastrointestinal symptoms, diagnosis of Fabry disease is often delayed for several years. Gastrointestinal involvement is often misdiagnosed or under-reported. It is therefore very important to consider Fabry disease in the differential diagnosis of chronic intestinal pseudo-obstruction.

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.

Limited responsiveness related to the minimal important difference of patient-reported outcomes in rare diseases

OBJECTIVES

To explore the responsiveness of patient-reported outcomes (PROs) in interventional studies involving patients with rare lysosomal storage diseases (LSDs).

STUDY DESIGN AND SETTING

We searched eight databases for experimental and nonexperimental studies. Pairs of trained reviewers independently screened articles and subsequently extracted data from the eligible studies. Among studies with 10 or more patients using a valid PRO, we assessed the responsiveness of PROs based on a reanalysis of the data using minimal important difference estimates. Our analyses focused on statistically significant within-group differences in PROs for observational studies or the statistically significant between-group differences in PRO scores for controlled studies.

RESULTS

Of 2,679 unique records, 62 interventional studies addressing patients with Fabry (55%), Gaucher (19%), Pompe (16%), and mucopolysaccharidoses (11%) proved eligible. The most frequently used PROs were the Short-Form-36 (25 studies), Brief Pain Inventory (20 studies), EuroQoL-5D (9 studies), and the Fatigue Severity Scale (6 studies). Observational studies suggest that PROs sometimes detect significant within-group changes when present. Randomized trials raise questions regarding the responsiveness of PROs to small differences between groups.

CONCLUSIONS

Most studies have relied on generic PROs to evaluate quality of life and symptoms in patients with rare LSDs. PROs appear more responsive in observational studies than randomized trials.

Gastrointestinal Symptoms of Patients with Fabry Disease

In order to characterize gastrointestinal (GI) symptoms of 50 patients with Fabry disease (FD) (22 M; age range: 4–70 y; 35 adults and 15 children), validated questionnaires of GI symptoms were used to diagnose the functional gastrointestinal disorders (FGIDs) of the patients with GI symptoms (33/50 (66%); 25/35 adults and 8/15 children) according to Rome III criteria. In 16/25 of these adults and 2/8 of these children, the symptoms mimicked FGID. The adult subgroup included patients with unspecified functional bowel disorder (n = 9), functional bloating (n = 7), and IBS (n = 5), and the child subgroup included patients with abdominal migraine (n = 1) and IBS (n = 1). Among the 25 adults, 14 reported feeling full after a regular-size meal, and 12 complained of abdominal bloating/distension. All of the children with GI symptoms complained of low abdominal pain associated with changes in the form of the stool/improvements with defecation. In conclusion, according to Rome III criteria, the most frequent diagnoses of FGID among the adults with FD were unspecified functional bowel disorder, followed by functional bloating and IBS. The most frequent GI symptom in the children in our population was IBS-like abdominal pain, while the adults exhibited a full feeling following a regular-size meal and abdominal bloating/distension.

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

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

Update on role of agalsidase alfa in management of Fabry disease

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

Enzyme replacement therapy for Fabry disease: some answers but more questions

Fabry disease (FD) is a multisystem, X-linked disorder of glycosphingolipid metabolism caused by enzyme deficiency of α-galactosidase A. Affected patients have symptoms including acroparesthesias, angiokeratomas, and hypohidrosis. More serious manifestations include debilitating pain and gastrointestinal symptoms, proteinuria and gradual deterioration of renal function leading to end-stage renal disease, hypertrophic cardiomyopathy, and stroke. Heterozygous females may have symptoms as severe as males with the classic phenotype. Before 2001, treatment of patients with FD was supportive. The successful development of enzyme replacement therapy (ERT) has been a great advancement in the treatment of patients with FD and can stabilize renal function and cardiac size, as well as improve pain and quality of life of patients with FD. In this review, we have provided a critical appraisal of the literature on the effects of ERT for FD. This analysis shows that data available on the treatment of FD are often derived from studies which are not controlled, rely on surrogate markers, and are of insufficient power to detect differences on hard clinical endpoints. Further studies of higher quality are needed to answer the questions that remain concerning the efficacy of ERT for FD.

Therapeutic goals in the treatment of Fabry disease

PURPOSE

Fabry disease is a progressive multiorgan, multisystem disorder that is caused by a deficiency in the lysosomal enzyme α-galactosidase A. Serious renal, cardiac, and cerebrovascular involvement are responsible for much of the morbidity and premature mortality associated with Fabry disease, and neuropathic pain, gastrointestinal problems, and hypohidrosis negatively affect quality of life of patients with Fabry disease. Fabry disease is X-linked, but women are often symptomatic and may be as severely affected as men.

METHODS

We propose a series of therapeutic and symptomatic goals for use in setting the expectations of enzyme replacement therapy and for assessing the response to enzyme replacement therapy in the treatment of Fabry disease.

RESULTS

Enzyme replacement therapy has been available since 2001 and has been associated with benefit in clinical trials, including stabilization of kidney function, improvement of cardiac structure and function, reduction in severity of neuropathic pain, and improvement in gastrointestinal involvement.

CONCLUSIONS

The presentation of these therapeutic goals will aid in the evaluation of response to enzyme replacement therapy and be useful in establishing an overall management plan for individual patients.

Effects of enzyme replacement therapy in Fabry disease--a comprehensive review of the medical literature

Enzyme replacement therapy with α-galactosidase A has been used to treat Fabry disease since 2001. This article reviews the published evidence for clinical efficacy of the two available enzyme preparations. We focused on heart, kidney, and nervous system manifestations, which impact both quality of life and overall prognosis. A literature search was undertaken to identify prospective open or randomized controlled trials of enzyme replacement therapy in patients with Fabry disease published since 2001. To date, no definitive conclusion can be drawn from studies that have directly compared therapeutic responses between the two commercially available enzyme preparations. Significant clinical benefits of enzyme replacement therapy have been demonstrated, mainly in patients at an early phase of the disease, with beneficial effects on heart, kidneys, pain, and quality of life in treated patients. Incidence of antibodies against agalsidase alfa and agalsidase beta observed during major clinical studies suggests a greater antigenic response to agalsidase beta. Further studies are required to confirm the long-term clinical benefits of enzyme replacement therapy. More studies with female patients are needed as are investigations of early initiation of enzyme replacement therapy to determine the optimal time to start treatment to prevent irreversible organ damage. The value of adjunctive and supportive therapies should also be rigorously analyzed.

Age adjusting severity scores for Anderson-Fabry disease

Anderson-Fabry Disease (AFD) is a life-threatening X-linked lysosomal storage disorder, caused by a deficiency of alpha galactosidase A. The disease affects males and females, and may present in childhood or adulthood. In the absence of a biomarker of disease burden or therapeutic response, scoring systems based on clinical manifestations, have been developed. Such global scores e.g. the Mainz Severity Score Index (MSSI) are confounded by the natural history of disease that deteriorates with age, making comparisons across age groups invalid. In this study the baseline MSSI, as adapted for data collected in the Fabry Outcome Survey (FOS) database (FOS-MSSI), was calculated for 655 females and 617 males with confirmed AFD. Using an ANCOVA model, equations for the predicted FOS-MSSI based on age were derived for males and females from data where patients from the UK or outside Europe were excluded. The initially excluded patients were used for validation. The predicted severity scores of UK and non-Europe-cohorts of adult and paediatric patients were found to follow the model produced for the European cohort thereby providing validation of the methodology. Deviation of the actual FOS-MSSI from the predicted was calculated and termed the age-adjusted score. Examples of the use of the age-adjusted score in individual patients, in comparison of mutations and in investigation of early factors which may impact on later severity of Fabry disease are given. This validated age and gender adjusted scoring system allows the comparison of disease severity in different subgroups such as genotypes without age or sex as confounding factors.

Agalsidase alfa for enzyme-replacement therapy in Fabry disease

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

The use of agalsidase alfa enzyme replacement therapy in the treatment of Fabry disease

BACKGROUND

Fabry disease is an X-linked lysosomal storage disease caused by deficiency of alpha-galactosidase A (alpha-Gal A), encoded by the GLA gene. The deficiency causes accumulation of neutral glycosphingolipids in various tissues, leading to neuronopathic pain, progressive renal dysfunction, cardiomyopathy and stroke. Enzyme replacement therapy (ERT) with agalsidase alfa (Replagal, Shire Human Genetic Therapies) is approved for use by 40 countries, but not the US.

OBJECTIVE

To evaluate agalsidase alfa in therapy of Fabry disease.

METHODS

An examination of relevant reports.

RESULTS/CONCLUSIONS

Clinical trials data, along with experience of the treatment collected through participation of treating physicians in a world-wide Fabry disease registry, have demonstrated that it improves pain and stabilizes renal function, as well as cardiomyopathy, in some patients. More data are needed to evaluate the role of treatment with this drug in the prevention of stroke and adverse cardiac events, and its overall effect on the lifespan and quality of life of affected individuals.

Early therapeutic intervention in females with Fabry disease?

Anderson-Fabry disease is an X-linked lysosomal storage disorder resulting from deficiency of alpha-galactosidase A. The subsequent accumulation of globotriaosylceramide (Gb3) in cells and tissues of the body has multisystemic effects and significantly impacts upon quality of life and survival of individuals with this condition. In general, Anderson-Fabry disease is more severe in male patients; however, despite X-linkage, females may develop severe signs and symptoms of the disease, although there is considerable phenotypic heterogeneity, which correlates most closely with age. Histological analyses of biopsies have shown evidence of Gb3 storage in the kidney and heart in female patients. Gb3 levels are also elevated in the urine of females, although plasma Gb3 levels are not reliably elevated. The efficacy of enzyme replacement therapy (ERT) with recombinant human alpha-galactosidase A has been demonstrated in females in a clinical trial and in observational studies, including those using data from outcome surveys. Benefits include a reduction in left ventricular mass, stabilization of renal function and improvements in pain and quality of life.

CONCLUSION

If early intervention with ERT in females is to be advocated, it is necessary to demonstrate not only that females with Anderson-Fabry disease have clinical and biochemical features of alpha-galactosidase A deficiency and respond to ERT, but also that early intervention prevents the onset of the later manifestations of the disorder. Any strategy for early therapy should also balance future advantages against any impact on quality of life.

Females with Fabry disease frequently have major organ involvement: lessons from the Fabry Registry

Fabry disease (FD) is an X-linked lysosomal storage disease caused by alpha-galactosidase A deficiency. The Fabry Registry is a global clinical effort to collect longitudinal data on FD. In the past, most "carrier" females were usually thought to be clinically unaffected. A systematic effort has been made to enroll all FD females, regardless of symptomology. Of the 1077 enrolled females in the Registry, 69.4% had symptoms and signs of FD. The median age at symptom onset among females was 13 years, and even though 84.1% had a positive family history, the diagnosis was not made until a median age of 31 years. Twenty percent experienced major cerebrovascular, cardiac, or renal events, at a median age of 46 years. Among adult females with estimated glomerular filtration rate (eGFR) data (N=638), 62.5% had an eGFR <90 ml/min/1.73 m2 and 19.0% had eGFR <60 ml/min/1.73 m2. Proteinuria 300 mg/day was present in 39.0% of females, and 22.2% had >1 gram/day. Quality of life (QoL), as measured by the SF-36((R)) survey, was impaired at a later age than in males, but both genders experience significantly impaired QoL from the third decade of life onward. Thus, females with FD have a significant risk for major organ involvement and decreased QoL. Females should be regularly monitored for signs and symptoms of FD, and considered for enzyme replacement therapy.

Gastrointestinal symptoms in 342 patients with Fabry disease: prevalence and response to enzyme replacement therapy

BACKGROUND & AIMS

Fabry disease is an X-linked deficiency of alpha-galactosidase A, resulting in lysosomal deposition of globotriaosylceramide in nearly all tissues. The disease frequently causes diarrhea and abdominal pain, which are assumed to arise from malfunction of enteric neurons and which mimic diarrhea-predominant irritable bowel syndrome (IBS). There are limited data about the prevalence and nature of gastrointestinal symptoms in patients with Fabry disease and the response to enzyme replacement therapy (ERT) in large cohorts. The aims of this study were to evaluate the nature and prevalence of gastrointestinal symptoms and their impact on health-related quality of life (HRQoL) in patients with Fabry disease and to analyze changes after 12 and 24 months of treatment with agalsidase alfa.

METHODS

Information about gastrointestinal symptoms was obtained from regular interviews before and during the time of ERT. Data on HRQoL were collected by using the EQ-5D questionnaire.

RESULTS

The overall prevalence of gastrointestinal symptoms was 52%, with abdominal pain and diarrhea being most frequent. Female patients were more frequently affected than male patients, and there was a high prevalence in children (abdominal pain, 49.3%; diarrhea 25.4%). ERT with agalsidase alfa reduced the prevalence of abdominal pain, with a statistically significant decrease in male patients and in children after 12 months of treatment.

CONCLUSIONS

The gastrointestinal symptomatology of Fabry disease is very similar to diarrhea-predominant IBS; however, pathophysiologic similarities remain to be elucidated. ERT reduced the prevalence of gastrointestinal symptoms in Fabry disease, particularly in children and male patients.

Novel therapeutic targets for the treatment of Fabry disease

Fabry disease is an X-linked lysosomal storage disorder resulting from deficient activity of alpha-galactosidase A. The traditional concept that is used to explain the complications of the disease involves progressive accumulation of globotriaosylceramide in endothelial and smooth muscle cells, resulting in vascular damage. Clinically, progressive renal insufficiency, cardiac involvement and brain pathology evolves. Two pharmaceutical companies have developed enzyme replacement therapy in Fabry disease. Although the first clinical trials showed great promise, it is clear that long-term effects are not as robust as was anticipated. Stabilisation of renal function and decreases in cardiac hypertrophy has been observed, but some patients may experience progressive complications. As there are recent indications that serum components contribute to the pathophysiology of Fabry disease, fundamental studies are needed to unravel the precise role and identity of these factors. Combination of these basic studies with clinical follow up may ultimately reveal when the 'point of no return' is reached. Advanced renal insufficiency seems to be a clinical indicator of lack of response, but other signs and symptoms are probably related to adverse outcome. It is anticipated that in the future controlled studies in early symptomatic or presymptomatic patients will be required. In addition, alternative strategies such as substrate reduction or chaperone therapy, either alone or in combination with enzyme replacement therapy, should be explored. Because Fabry disease is rare, collaborative efforts should be undertaken and openness of data should be strived for.

Weekly enzyme replacement therapy may slow decline of renal function in patients with Fabry disease who are on long-term biweekly dosing

This study was performed to determine whether adult male patients with Fabry disease who demonstrate a continuing decline in renal function despite 2 to 4 yr of conventionally dosed agalsidase alfa therapy (0.2 mg/kg every other week [EOW]) show an improved slope of decline with weekly administration using the same dosage. Eleven (27%) of 41 adult male patients with Fabry disease who participated in long-term agalsidase alfa clinical trials and who had demonstrated a slope of decline in estimated GFR (eGFR) of > or =5 ml/min per 1.73 m(2)/yr while receiving long-term treatment with agalsidase alfa at the currently recommended dosage of 0.2 mg/kg, infused EOW, were enrolled in this open-label, prospective study. Patients were switched from EOW to weekly infusions and followed for an additional 24 mo. Before switching to weekly dosing, eGFR was 53.7 +/- 6.3 ml/min per 1.73 m(2) (mean +/- SEM), and mean rate of change in eGFR was -8.0 +/- 0.8 ml/min per 1.73 m(2)/yr. During the 24-mo follow-up period after switching to weekly dosing, the mean rate of change in eGFR was observed to slow to -3.3 +/- 1.4 ml/min/1.73 m(2)/yr (P = 0.01 versus EOW). After switching to weekly dosing, three patients demonstrated an improvement in eGFR and six patients demonstrated a slowing in the rate of eGFR decline; only two patients failed to improve their eGFR slope. A multiple regression model confirmed that the weekly infusion regimen was the strongest explanatory variable for the change in eGFR (P = 0.0008), with a weaker contribution from the concomitant use of angiotensin converting enzyme inhibitors/angiotensin receptor blockers (P = 0.02). These results suggest that weekly infusions of agalsidase alfa at a dosage of 0.2 mg/kg may be beneficial in the subgroup of patients who have Fabry disease and whose kidney function continues to decline after 2 to 4 yr or more of standard EOW dosing.

Gastrointestinal symptoms in Fabry disease: everything is possible, including treatment

Gastrointestinal symptoms in Fabry disease were first described independently by William Anderson and Johannes Fabry. Case reports and case series suggest that the whole gastrointestinal tract may be affected in patients with Fabry disease. The Fabry Outcome Survey (FOS) database supports these observations. The overall prevalence of gastrointestinal involvement reported in a study of 342 patients (271 adults; 71 children) enrolled in FOS was 52% (49.8% in adults, 60.8% in children). Abdominal pain was the most prevalent symptom. The median age at onset of gastrointestinal symptoms was 14 years, similar to the age at onset of acroparaesthesia. The prevalence of gastrointestinal symptoms was reduced in patients after receiving enzyme replacement therapy with agalsidase alfa for 12 and 24 months. There was no correlation between gastrointestinal symptoms and body mass index.

CONCLUSION

Gastrointestinal symptoms in Fabry disease may have been underestimated. The FOS database supports previous reports of beneficial effects of enzyme replacement therapy on gastrointestinal symptoms in Fabry disease.

Agalsidase alfa therapy for Fabry disease

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

A diagnosis of Fabry gastrointestinal disease by chance: a case report

Fabry disease is an X-linked lysosomal storage disease caused by a deficiency of alpha-galactosidase A. This determines an accumulation of globotriaosylceramide within lysosomes. The clinical picture is highly variable and depends on cellular storage deposition. Renal, cardiac and nervous system are the most frequent organs involved. Gastrointestinal involvement is also present, associated with other clinical signs of Fabry disease and sometimes can be a prominent clinical manifestation. We describe a Fabry disease case in which gastrointestinal involvement was the first and the only clinical sign of Fabry disease and a diagnosis of Fabry disease was made by chance during a family screening. Enzyme replacement therapy was started and after 3 months, there was a complete disappearance of signs.

Clinical results of enzyme replacement therapy in Fabry disease: a comprehensive review of literature

Enzyme replacement therapy (ERT) has been used to treat Fabry disease - a progressive lysosomal storage disorder - since 2001. Two preparations of the enzyme alpha-galactosidase A are available in Europe: agalsidase alpha, produced in a human cell line, and agalsidase beta, produced in Chinese hamster ovary cells. To review critically the published evidence for the clinical efficacy of these two enzyme preparations. A systematic literature search was undertaken to identify open or randomised controlled trials published on Fabry disease since 2001. Eleven trials fulfilled the criteria for inclusion in this review, of a total of 586 references on Fabry disease. To date, no direct comparisons exists between the two available enzyme preparations. Significant clinical benefits compared with placebo, however, have been demonstrated with ERT, with positive effects on the heart, kidneys, nervous system and quality of life. The quality of most of these publications was less than optimal. Further prospective studies are required to confirm the long-term clinical benefits of ERT. More studies are also needed on the effects of ERT in women and on the use of ERT early in the course of Fabry disease, to prevent organ damage. Large national and international outcomes databases will also be invaluable in evaluating treatment effects and safety.

[Fabry disease in Spain: first analysis of the response to enzyme replacement therapy]

BACKGROUND AND OBJECTIVE

Fabry disease is a X-linked lysosomal disorder caused by a deficient activity of the enzyme alfa-galactosidase A. Lack of enzyme activity results in progressive accumulation of globotriaosylceramide (Gb3) leading to multiorgan dysfunction and early death. Enzyme replacement therapy (ERT) has recently become available and the database Fabry Outcome Survey (FOS) of Spain gives us the opportunity to asses the efficacy of this therapy. Our objective is to describe the safety and the effects on renal, cardiac and neurological (pain) aspects of ERT with agalsidase alfa.

PATIENTS AND METHOD

The effects of 1, 2, 3 and 4 years of ERT with agalsidase alfa on renal function (assessed by estimated glomerular filtration rate), proteinuria, heart size (assessed by echocardiography), arrhythmias, cardiac valvular anomalies and pain (assessed by the need of concomitant pain therapy) were analyzed in 33 patients under treatment. Safety of ERT was assessed by the reported infusion-related reactions in FOS.

RESULTS

Overall, treatment with agalsidase alfa stabilized renal function, but the final result depends on the onset of ERT: there is a tendency to stabilization of renal function in those patients with mild deterioration of renal function, a tendency to improve in those patients with moderate deterioration and to worse in those with severe deterioration of renal function. Proteinuria and left ventricular heart size also estabilized under ERT, and pain improved. TSE infusion-related reactions occurred with an incidence of 0.7%.

CONCLUSIONS

ERT with agalsidase alfa is safe and stabilized the abnormal clinical parameters observed in patients with Fabry disease.

Heterozygous Fabry women are not just carriers, but have a significant burden of disease and impaired quality of life

PURPOSE

To determine if there is significant symptomatology in women with heterozygous alpha-galactosidase mutations.

METHODS

Data from medical records of the 44 heterozygous females followed at Cedars-Sinai Medical Center were compiled and analyzed for symptoms of Fabry disease. Quality of life data were also analyzed.

RESULTS

Seventy-six percent were referred due to an affected male relative; 76% reported acroparesthesias as their first symptom. A mean of 15.7 years elapsed from onset of first symptoms to the diagnosis. Quality of life, measured by the SF-36 survey, was globally reduced. Pain affected mood and enjoyment of life. Central/peripheral nervous, cardiopulmonary, and renal system manifestations of Fabry disease were present far above that predicted for random X-inactivation of the normal allele. Fatigue, present in 59%, was associated with reduced maximum oxygen consumption (P=0.049); exercise intolerance, present in 83%, was associated with reduced maximal heart rate during exercise testing (P=0.0089). Women diagnosed via family history experienced more angina (P=0.035), decreased vibration sense (P=0.026), and had a worse percentage predicted FEF25-75 (P=0.037) compared to women diagnosed because of symptoms.

CONCLUSIONS

This study indicates that the asymptomatic female carrier of Fabry disease is the exception, not the rule: heterozygotes suffer from significant multisystemic disease and reduced quality of life and must be monitored and treated accordingly.

Enzyme replacement therapy with agalsidase alfa in children with Fabry disease

AIM

To assess the effects of enzyme replacement therapy (ERT) in children with Fabry disease.

METHODS

Safety and efficacy of ERT with agalsidase alfa, 0.2 mg/kg infused over 40 minutes every 2 weeks for 23 weeks, were studied in a multicentre open-label trial in nine boys and four girls. Median age at the start of the study was 11.0 years (range 3.5-18 years).

RESULTS

Fifty-four adverse events were reported in 11 patients. No serious adverse events related to ERT were reported. Twelve of the 54 adverse events were considered possibly or probably related to ERT. Infusion reactions (8 mild, 3 moderate) occurred in four boys, in seven infusions. One boy developed IgG antibodies, although he continued to make good clinical progress. At the end of the study, two of the four boys and the one girl on regular pain medication at baseline had stopped taking analgesics. Brief Pain Inventory (BPI) scores decreased in most patients by week 12 and were sustained until the end of the study. This change was greater in the boys, who had higher (worse) BPI scores at baseline. Pain-related quality of life (QoL) scores also decreased during the study. Plasma globotriaosylceramide concentrations and urinary globotriaosylceramide:sphingomyelin ratios decreased after 12 and 23 weeks of therapy, particularly in the boys. Increases in sweat volume were recorded in three out of five of the boys and in one of two girls tested after 23 weeks of treatment.

CONCLUSION

ERT with agalsidase alfa in children with Fabry disease is well tolerated and, in the short term, appears to decrease pain and to improve pain-related QoL.

Gastrointestinal manifestations of Fabry disease: clinical response to enzyme replacement therapy

Gastrointestinal symptoms are often an early and prominent manifestation of Fabry disease, an X-linked inborn error of metabolism caused by the deficient activity of the lysosomal enzyme, alpha-galactosidase A. This enzyme deficiency results in the progressive accumulation of globotriaosylceramide and other glycosphingolipids in tissue lysosomes throughout the body. In classically affected patients, glycosphingolipid accumulation in the vascular endothelium eventually culminates in life-threatening renal, cardiac, and cerebrovascular disease. In addition, over 50% of patients experience post-prandial abdominal pain and diarrhea that interferes with the ability to work and quality of life. Here, we describe four males aged 17-40 years with classic Fabry disease and severe gastrointestinal symptoms who participated in clinical trials of enzyme replacement therapy with agalsidase beta (Fabrazyme, 1 mg/kg every 2 weeks). Before therapy, the three adult patients experienced post-prandial abdominal pain, bloating, and severe diarrhea with 7-10 bowel movements per day every day and the 17-year-old had weekly episodes of diarrhea with six bowel movements per day. Other symptoms included vomiting, food intolerance, and poor weight gain. All patients took medications for these symptoms (diphenoxylate-atropine [Lomotil], ranitidine hydrochloride [Zantac], or sulfasalazine). After 6-7 months of agalsidase beta therapy, all patients reported "no or only occasional" abdominal pain or diarrhea, had discontinued their gastrointestinal medications, and had gained 3-8 kg. These marked improvements in gastrointestinal symptoms have persisted for over 3 years of treatment. In such patients, enzyme replacement at 1 mg/kg effects an early and significant clinical improvement in the gastrointestinal manifestations of Fabry disease.