Effects of enzyme replacement therapy on pain and health related quality of life in patients with Fabry disease: data from FOS (Fabry Outcome Survey)

A phase III, open-label clinical trial evaluating pegunigalsidase alfa administered every 4 weeks in adults with Fabry disease previously treated with other enzyme replacement therapies

Pegunigalsidase alfa, a PEGylated α-galactosidase A enzyme replacement therapy (ERT) for Fabry disease, has a longer plasma half-life than other ERTs administered intravenously every 2 weeks (E2W). BRIGHT (NCT03180840) was a phase III, open-label study in adults with Fabry disease, previously treated with agalsidase alfa or beta E2W for ≥3 years, who switched to 2 mg/kg pegunigalsidase alfa every 4 weeks (E4W) for 52 weeks. Primary objective assessed safety, including number of treatment-emergent adverse events (TEAEs). Thirty patients were enrolled (24 males); 23 previously received agalsidase beta. Pegunigalsidase alfa plasma concentrations remained above the lower limit of quantification throughout the 4-week dosing interval. Thirty-three of 182 TEAEs (in 9 patients) were considered treatment-related; all were mild/moderate. No patients developed de novo anti-drug antibodies (ADAs). In the efficacy analysis (n = 29), median (inter-quartile range) eGFR change from baseline over 52 weeks was -1.9 (-5.9; 1.8) mL/min/1.73 m2 (n = 28; males [n = 22]: -2.4 [-5.2; 3.2]; females [n = 6]: -0.7 [-9.2; 2.0]). Overall, median eGFR slope was -1.9 (-8.3; 1.9) mL/min/1.73 m2/year (ADA-negative [n = 20]: -1.2 [-6.4; 2.6]; ADA-positive [n = 9]: -8.4 [-11.6; -1.0]). Lyso-Gb3 concentrations were low and stable in females, with a slight increase in males (9/24 ADA-positive). The BRIGHT study results suggest that 2 mg/kg pegunigalsidase alfa E4W is tolerated well in stable adult patients with Fabry disease. Due to the low number of patients in this study, more research is needed to demonstrate the effects of pegunigalsidase alfa given E4W. Further evidence, outside of this clinical trial, should be factored in for physicians to prolong the biweekly ERT intervals to E4W. TAKE-HOME MESSAGE: Treatment with 2 mg/kg pegunigalsidase alfa every 4 weeks could offer a new treatment option for patients with Fabry disease.

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

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

Screening for health-related quality of life and its determinants in Fabry disease: A cross-sectional multicenter study

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by α-galactosidase A (α-Gal A) deficiency. The progressive accumulation of globotriaosylceramide results in life-threatening complications, including renal, cardiac, and cerebrovascular diseases. In order to improve health care of FD-patients, knowledge of its predictors is important. The aim of our study was to evaluate health-related quality of life (HrQol) in FD and to identify its independent determinants by exploring a wide range of demographic, social and clinical parameters.

RESULTS

In this cross-sectional multicenter study, 135 adult patients with FD were recruited at three specialized European centers in Germany and Switzerland. Demographics, social status and clinical parameters as well as data on HrQol (EQ5D, EQ VAS) and depression were collected by means of self-reporting questionnaires and confirmed by medical records. HrQol and its predictors were evaluated by univariate and multivariate regression analyses. The study population consisted of 78 female and 57 male FD patients (median age 48 yrs) of whom 80.7% (N = 109) were on enzyme replacement therapy (ERT) and 10.4% (N = 14) were on chaperone treatment. Univariate analysis revealed various factors reducing HrQol such as age > 40 years, classic phenotype, organ involvement (kidney and heart disease, stroke/transient ischemic attack (TIA), gastrointestinal disturbances), depression, and burning limb pain. However, only the following factors were identified as independent predictors of decreased HrQol: classic phenotype, kidney and heart disease, stroke/TIA, depression, and burning limb pain. ERT and chaperone therapy were independent determinants of increased HrQol.

CONCLUSIONS

Modifiable factors, such as burning limb pain and depression, identified as independent predictors of HrQol-deterioration should be addressed in programs aiming to improve HrQol in FD. A multidisciplinary approach is essential in FD-patients since diverse organ involvement prominently compromises HrQol in affected patients. Our findings showed that the classic phenotype is a strong predictor of worsening HrQol.

The estimation of health state utility values in rare diseases: do the approaches in submissions for NICE technology appraisals reflect the existing literature? A scoping review

BACKGROUND

Rare diseases negatively impact patients' quality of life, but the estimation of health state utility values (HSUVs) in research studies and cost-utility models for health technology assessment is challenging.

OBJECTIVES

This study compared the methods for estimating the HSUVs included in manufacturers' submissions of orphan drugs to the National Institute for Health and Care Excellence (NICE) with those of published studies addressing the same rare diseases to understand whether manufacturers fully exploited the existing literature in developing their economic models.

METHODS

All NICE Technology Appraisal (TA) and Highly Specialized Technologies (HST) guidance documents of non-cancer European Medicines Agency (EMA) orphan medicinal products were reviewed and compared with any published primary studies, retrieved via PubMed until November 2020, and estimating HSUVs for the same conditions addressed in manufacturers' submissions.

RESULTS

We identified 22 NICE TA/HST appraisal reports addressing 19 different rare diseases. Sixteen reports presented original HSUVs estimated using EQ-5D or Health Utility Index (n = 12), direct methods (n = 2) or mapping (n = 2), while the other six included values obtained from the literature only. In parallel, we identified 111 published studies: 86.6% used preference-based measures (mainly EQ-5D, 60.7%), 12.5% direct techniques, and 2.7% mapping. The collection of values from non-patient populations (using 'vignettes') was more frequent in manufacturers' submissions than in the literature (22.7% vs. 8.0%).

CONCLUSIONS

The agreement on methodological choices between manufacturers' submissions and published literature was only partial. More efforts should be made by manufacturers to accurately reflect the academic literature and its methodological recommendations in orphan drugs submissions.

Cardiovascular Involvement in Fabry's Disease: New Advances in Diagnostic Strategies, Outcome Prediction and Management

Cardiovascular involvement is common in Fabry's disease and is the leading cause of morbidity and mortality. The research is focused on identifying diagnostic clues suggestive of cardiovascular involvement in the preclinical stage of the disease through clinical and imaging markers. Different pathophysiologically driven therapies are currently or will soon be available for the treatment of Fabry's disease, with the most significant benefit observed in the early stages of the disease. Thus, early diagnosis and risk stratification for adverse outcomes are crucial to determine when to start an aetiological treatment. This review describes the cardiovascular involvement in Fabry's disease, focusing on the advances in diagnostic strategies, outcome prediction and disease management.

Shared decision making between patients with Fabry disease and physicians in Japan: An online survey

Background

Fabry disease is a rare, progressive genetic lysosomal disorder that can cause multisystem organ dysfunction. With increasing treatment options for Fabry disease, it is imperative that patients discuss and select treatment plans in conjunction with their physicians. Although shared decision making (SDM) should be recommended for clinical decision making in disease management, evidence is limited as to how patients in Japan are involved in the choice of their Fabry disease treatment and if other gaps exist with physicians in the perception of Fabry disease management.

Objective

The main objective of the study was to assess the degree of agreement between patients and treating physicians in the SDM process as assessed by the SDM-Q-9 and SDM-Q-Doc questionnaires. In parallel, this study also investigated other factors that might impact the SDM process.

Methods

This was a cross-sectional web-based questionnaire survey of Japanese patients with Fabry disease and their treating physicians conducted from February 2021 to June 2021. Online surveys were developed for patients and physicians, consisting of seven items, including the Japanese version of the 9-item SDM Questionnaire for patients (SDM-Q-9) and physicians (SDM-Q-Doc). Physicians were divided into two cohorts: non-paired and paired with patients. Only the paired cohort physicians answered the SDM questionnaire.

Results

A total of 99 physicians and 30 patients answered the respective questionnaires. Among these, 13 physicians were included in a paired SDM analysis with patients. Mean (standard deviation [SD]) patient age at diagnosis of Fabry disease was 47.5 (15.8) years, and 14 (46.7%) were male. Both physicians in the paired cohort and patients considered patient-reported outcomes (both 76.7%) and the findings from laboratory testing as important (90.0% and 60.0% respectively). However, regarding symptoms that affect quality of life of patients, perception gaps were identified in that physicians in the paired cohort placed less importance on patient-reported outcome-related symptoms such as sweating abnormalities and gastrointestinal symptoms than their patients (0% [0/17] and 44.4% [8/18], 11.8% [2/17] and 38.9% [7/18], respectively). In the paired analysis, there was no significant difference in total SDM score between patients and physicians (p = 0.82). However, the largest discordance in perception between patients and physicians was identified for the explanation of the advantages and disadvantages of the treatment options (weighted Kappa coefficient = 0.14).

Conclusion

This survey revealed a gap in the perception of disease burden affecting patients' quality of life, and a recognition gap between physicians and patients when they discussed the advantages and disadvantages of treatment options. To improve the SDM process in Fabry disease management and treatment, practical solutions for bridging these gaps should be considered.

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

Background

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

Results

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

Conclusion

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

Understanding and modifying Fabry disease: Rationale and design of a pivotal Phase 3 study and results from a patient-reported outcome validation study

The use of available treatments for Fabry disease (FD) (including enzyme replacement therapy [ERT]) may be restricted by their limited symptom improvement and mode of administration. Lucerastat is currently being investigated in the MODIFY study as oral substrate reduction therapy for the treatment of FD. By reducing the net globotriaosylceramide (Gb3) load in tissues, lucerastat has disease-modifying potential to improve symptoms and delay disease progression.

MODIFY is a multicenter, double-blind, randomized, placebo-controlled, parallel-group Phase 3 study (ClinicalTrial.gov: NCT03425539); here we present the rationale and design of this study. Eligible adults with a genetically confirmed diagnosis of FD and FD-specific neuropathic pain entered screening. Patients were randomized (2:1) to receive either oral lucerastat twice daily or placebo for 6 months; treatment allocation was stratified according to sex and ERT treatment status. The main objectives of MODIFY are to assess the effects of lucerastat on neuropathic pain, gastrointestinal (GI) symptoms, FD biomarkers, and determine its safety and tolerability.

Neuropathic pain and GI symptoms are key features of FD that have a significant impact on quality of life. Despite various tools available to assess pain and GI symptoms, there are currently limited tools available to assess neuropathic and GI symptoms in FD, validated according to health authority guidelines. Based on FDA recommendations, we undertook a patient-reported outcome (PRO) validation study, using a novel eDiary-based PRO tool to assess the validity of evaluating neuropathic pain as a primary efficacy endpoint in MODIFY. Results from the PRO validation study are included.

To date, MODIFY is the largest Phase 3 clinical study conducted in patients with FD. Enrollment to MODIFY is now complete, with 118 patients randomized. Results will be presented in a separate publication. Long-term effects of lucerastat are being assessed in the ongoing open-label extension study (NCT03737214).

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There remains a need for treating patients with Fabry disease.

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MODIFY investigated lucerastat as substrate reduction therapy for Fabry disease.

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Limited tools are available to assess neuropathic and GI symptoms in Fabry disease.

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MODIFY assessed neuropathic pain and GI symptoms as primary and secondary efficacy endpoints.

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MODIFY used FDA-recommended validated tools for primary and secondary efficacy endpoints.

Multidisciplinary Management of Fabry Disease: Current Perspectives

Fabry disease (FD) is a rare, recessive X-linked, multisystemic lysosomal storage disorder (LSD) that results from a deficiency in the hydrolase alpha-galactosidase A (α-GalA) caused by a GLA gene variant. The progressive accumulation of the glycosphingolipid globotriaosylceramide (Gb3) in organs such as skin, kidney, brain, joints, vascular walls and eyes are responsible for the wide spectrum of clinical manifestations, often unspecific. In result, clinically relevant and life-threatening complications, such as malignant ventricular arrhythmia, sudden cardiac death, end stage kidney failure and stroke may occur. In this review, we will describe the clinical features and the current perspectives in the multidisciplinary management Of FD patients.

Health-related quality of life in Norwegian adults with Fabry disease: Disease severity, pain, fatigue and psychological distress

Health-related quality of life (HRQOL) is reduced in Fabry disease (FD) and associated with clinical disease manifestations, but few have used Fabry-specific severity scores to study how disease burden interferes with quality of life. We investigated how the Fabry DS3, consisting of four somatic domains and one patient-reported item, associates with HRQOL, while also evaluating fatigue, pain and psychological distress as possible predictors. Thirty-six adults with FD completed the Short-form Health Survey (SF-36), the hospital anxiety and depression scale (HADS), the brief pain inventory (BPI) and reported fatigue on a visual analog scale. Clinical data were collected from the last multidisciplinary hospital visit. Using correlation and hierarchical linear regression analyses, we examined associations between demographic, clinical and self-reported predictors and the SF-36 physical (PCS) and mental (MCS) component summary scores. Males scored lower than the general population in all SF-36 domains (P < .05). General health and social functioning were reduced in females. Before including self-reported symptom scores, DS3 showed associations with PCS (P = .009). Our fully adjusted model explained 66% of the variation in PCS, where education (P = .040) and fatigue (P = .002) retained significance. With HADS depression score (P = .001) as the sole significant factor, our regression model explained 56% of the variation in MCS. The DS3 score has implications for HRQOL in FD. Low education and fatigue represent major barriers to physical well-being, while depression strongly influences mental quality of life. Fatigue should be recognized as an important endpoint in future FD trials. Increased efforts to diagnose and treat affective disorders are warranted.

Survey about the Quality of Life of Italian Patients with Fabry Disease

Fabry disease (FD) is a genetic disease included in the group of lysosomal storage disorders, caused by X-linked deficiency of the enzyme alpha-galactosidase A. The aim of this study was to evaluate different aspects related to the quality of life (QoL) of a multicentre cohort of Italian patients with FD. An observational survey was conducted to measure health-related quality of life (HR-QoL) in FD patients using the CAPI (Computer-Assisted Personal Interview) method: 106 patients (mostly women) responded to the questionnaire. Geographically, 53.7% of patients lived in northern Italy, 18.9% in central Italy and 27.4% in southern Italy or the Islands. All data were collected through a five-dimensional EuroQoL questionnaire referring to functional aspects (mobility, personal care, routine activities) and perception of physical/mental well-being (pain or discomfort, anxiety or depression). A descriptive analysis of responses was performed; FD patients were compared in terms of QoL with subjects suffering from other chronic diseases, such as Crohn’s disease, chronic hepatitis, cirrhosis and multiple sclerosis. Difficulty in normal daily activities was reported by 47.2% of FD patients. About one third of subjects also had mobility difficulties. Feelings of loneliness and isolation were reported by 33.3% of those being 60–69 years old. Anxiety was equally reported in both oldest and youngest patients (66.7%), while depression, relational problems, fear of other people’s judgement increased along with age, reaching 66.7% in the over-70-years group. Male patients were largely troubled about the risk of physical disability, particularly those aged 60 years or over. Furthermore, FD patients had a poorer QoL than people suffering from other chronic inflammatory disorders. Our study upholds that FD patients have a poor QoL, as already known, negatively impacting psychic well-being and social activities. Our survey has also found a worse QoL in FD patients compared with other severe chronic disorders.

The impact of demographic and clinical characteristics on the trajectories of health-related quality of life among patients with Fabry disease

Background

Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by multiorgan dysfunction. Since individuals with FD usually experience progressive clinical disease manifestations, their health-related quality of life (HRQOL) is expected to change over time. However, there is limited longitudinal research examining HRQOL outcomes in individuals with FD. We aimed to: assess longitudinal outcomes in HRQOL in adults with FD; examine the physical- and mental HRQOL trajectories at the initial registration (baseline), 3–5 year, and 7–13 year follow-ups; and evaluate the possible associations of age, sex and medical complications with the physical- and mental HRQOL trajectories.

Methods

Forty-three individuals with FD (53% female) who were aged 18 to 81 years at baseline attended clinical follow-up visits between 2006 and 2020. Medical records were extracted retrospectively. Demographics and the 36-item Short-Form Health Survey (SF-36) were recorded at scheduled visits, except for the last data collection which was prospectively obtained in 2020. The physical (PCS) and mental (MCS) composite scores (SF-36) were chosen as outcome measures.

Results

The eight SF-36 domain scores were stable over a span of 13 years, and only physical- and social functioning domains worsened clinically over this follow-up period. Mean baseline SF-36 domain scores were all significantly lower (decreased HRQOL) in the FD sample compared with Norwegian population norms. Two hierarchical linear models were run to examine whether demographics and medical complications (measured at the last clinical visit) predicted physical and mental HRQOL trajectories. Age above 47 years (p < 0.001), male sex (p = 0.027), small fibre neuropathy (p < 0.001), renal dysfunction (p < 0.001), and cerebrovascular events (p = 0.003) were associated with lower HRQOL over time. No significant interactions were found between the time of follow up and the abovementioned predictors of HRQOL.

Conclusions

Overall HRQOL trajectories remained stable between baseline, 3–5 year, and 7–13 year follow-ups, with the majority of individuals reporting decreased physical and mental HRQOL. Medical complications in combination with older age and male sex are important predictors of lower HRQOL in FD. Awareness of this relationship is valuable both for health care providers and for patients. The findings provide indicators that can guide treatment decisions to improve physical and mental HRQOL outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02066-y.

The future of newborn screening for lysosomal disorders

The goal of newborn screening is to enhance the outcome of individuals with serious, treatable disorders through early, pre-symptomatic detection. The lysosomal storage disorders (LSDs) comprise a group of more than 50 diseases with a combined frequency of approximately 1:7000. With the availability of existing and new enzyme replacement therapies, small molecule treatments and gene therapies, there is increasing interest in screening newborns for LSDs with the goal of reducing disease-related morbidity and mortality through early detection. Novel screening methods are being developed, including efforts to enhance accuracy of screening using an array of multi-tiered, genomic, statistical, and bioinformatic approaches. While NBS data for Gaucher disease, Fabry disease, Krabbe disease, MPS I, and Pompe disease has demonstrated the feasibility of widespread screening, it has also highlighted some of the complexities of screening for LSDs. These include the identification of infants with later-onset, untreatable, and uncertain phenotypes, raising interesting ethical concerns that should be addressed as part of the NBS implementation process. Taken together, these efforts will provide critical, detailed data to help guide objective, ethically sensitive decision-making about NBS for LSDs.

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.

The correlation of small fiber neuropathy with pain intensity and age in patients with Fabry's disease: A cross sectional study within a large Taiwanese family

Background

The relationships among small fiber neuropathy, age, sex and pain intensity in the context of Fabry's disease remain unclear. We aim to study the correlations of small fiber neuropathy, age, sex and pain intensity in Fabry patients.

Methods

We evaluated C-fiber function by recording the withdrawal latencies to painful heat stimulus (WLPHS) when each subject's right hand was immersed in a 50 °C hot water bath and correlated this parameter with the patient's perceived pain intensity and quality of life assessed by the short-form McGill Pain Questionnaire (SF-MPQ) in a large Taiwanese Fabry family and normal controls.

Results

Male Fabry patients showed a significantly increased WLPHS compared to that of normal controls. Furthermore, male Fabry patients showed a positive correlation of increased WLPHS with patient age. The SF-MPQ of male Fabry patients showed a bell distribution with age, and maximal pain scores were detected between the ages of the early 20s and late 40s. In contrast, the female Fabry patients had variable associations of WLPHS and SF-MPQ with age.

Conclusions

We proposed a probable mechanism by which globotriaosylceramide (Gb3) or globotriaosylsphingosine (lyso-Gb3) is gradually deposited into the small nerve bundles with increasing age, which induces continuous damage and produces injury discharges to sustain neuropathic pain in young male Fabry patients. However, once the small fibers are reduced to a certain degree, they no longer produce enough noxious discharges to sustain neuropathic pains in older male Fabry patients, which leads these patients to have lower SF-MPQ scores. In contrast, female Fabry patients had less and variable small fiber damage, pain intensity and clinical signs/symptoms.

Symptoms and Quality of Life in Patients with Fabry Disease: Results from an International Patient Survey

INTRODUCTION

Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency of α-galactosidase A. Symptoms include neuropathic pain and gastrointestinal problems, such as diarrhoea. To inform and support the design of a Phase III clinical trial for a new oral treatment for Fabry disease, this study evaluated patients' experiences of Fabry disease symptoms, the impact of symptoms on their quality of life, and their views on participating in clinical trials.

METHODS

An online survey questionnaire was distributed to patients with Fabry disease, through relevant patient organisations. The questionnaire consisted mainly of quantitative, closed questions with pre-defined response options. Fabry-specific pain intensity and its impact on quality of life were rated on a scale from 0 to 10.

RESULTS

In total, 367 patients completed the survey, of whom half reported frequent pain, moderate to severe pain, and pain in their hands and feet. Pain frequency, intensity and location were similar for males and females. There was no clear association between Fabry-specific pain and the use of enzyme replacement therapy (ERT), with moderate to severe pain reported by 80.4% of participants receiving ERT and by 75.0% of participants not receiving ERT. Of participants who were receiving ERT, 35.7% said they were willing to discontinue it to take part in a clinical trial testing a new oral drug for treating Fabry disease. Gastrointestinal symptoms were more heterogeneous in nature and frequency than Fabry-specific pain, but still affected a significant proportion of participants.

CONCLUSIONS

Both male and female patients with Fabry disease experience significant Fabry-specific pain, which affects their quality of life. Furthermore, frequent diarrhoea affects many patients. The symptoms occur independently of the use of ERT. This suggests the healthcare needs of patients with Fabry disease are not being fully met, and additional treatments are required to improve symptoms and quality of life.

FUNDING

This study was sponsored by Actelion Pharmaceuticals Ltd. Study sponsorship was transferred to Idorsia Pharmaceuticals Ltd in July 2018.

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

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

Patient and observer reported outcome measures to evaluate health-related quality of life in inherited metabolic diseases: a scoping review

Background

Health-related Quality of Life (HrQoL) is a multidimensional measure, which has gained clinical and social relevance. Implementation of a patient-centred approach to both clinical research and care settings, has increased the recognition of patient and/or observer reported outcome measures (PROMs or ObsROMs) as informative and reliable tools for HrQoL assessment. Inherited Metabolic Diseases (IMDs) are a group of heterogeneous conditions with phenotypes ranging from mild to severe and mostly lacking effective therapies. Consequently, HrQoL evaluation is particularly relevant.

Objectives

We aimed to: (1) identify patient and/or caregiver-reported HrQoL instruments used among IMDs; (2) identify the main results of the application of each HrQoL tool and (3) evaluate the main limitations of HrQoL instruments and study design/methodology in IMDs.

Methods

A scoping review was conducted using methods outlined by Arksey and O’Malley. Additionally, we critically analysed each article to identify the HrQoL study drawbacks.

Results

Of the 1954 studies identified, 131 addressed HrQoL of IMDs patients using PROMs and/or ObsROMs, both in observational or interventional studies. In total, we identified 32 HrQoL instruments destined to self- or proxy-completion; only 2% were disease-specific. Multiple tools (both generic and disease-specific) proved to be responsive to changes in HrQoL; the SF-36 and PedsQL questionnaires were the most frequently used in the adult and pediatric populations, respectively. Furthermore, proxy data often demonstrated to be a reliable approach complementing self-reported HrQoL scores. Nevertheless, numerous limitations were identified especially due to the rarity of these conditions.

Conclusions

HrQoL is still not frequently assessed in IMDs. However, our results show successful examples of the use of patient-reported HrQoL instruments in this field. The importance of HrQoL measurement for clinical research and therapy development, incites to further research in HrQoL PROMs’ and ObsROMs’ creation and validation in IMDs.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0953-9) contains supplementary material, which is available to authorized users.

Reaccumulation of globotriaosylceramide in podocytes after agalsidase dose reduction in young Fabry patients

Background

Agalsidase-α 0.2 mg/kg every other week (eow) and agalsidase-β 1.0 mg/kg/eow are licensed in Europe as equipotent treatment of the α-galactosidase deficiency in Fabry disease. This case series describes the effects of agalsidase dose adjustments in serial kidney biopsies in switch patients.

Methods

All treatment-naïve patients with classical Fabry disease in our centre started on agalsidase-β 1.0 mg/kg/eow and subsequently switched to agalsidase-α 0.2 mg/kg/eow were included ( n = 3). The median age at enzyme replacement therapy start was 11 (range 7-18) years. Kidney biopsies were performed at baseline, after 5 years of agalsidase-β 1.0 mg/kg/eow and after 3 subsequent years of agalsidase-α 0.2 mg/kg/eow. One patient was re-biopsied 2 years after reswitch to agalsidase-β 1.0 mg/kg/eow. The scoring system of the International Scoring Group of Fabry Nephropathy was used.

Results

The patients completely cleared globotriaosylceramide (GL3) from mesangial and endothelial cells and partly cleared podocytes on agalsidase-β 1.0 mg/kg/eow. Reaccumulation of GL3 in podocytes, but not in the mesangium or endothelium, occurred after 3 years of agalsidase-α 0.2 mg/kg/eow. Subsequent reduction of podocyte GL3 was observed in the single patient rebiopsied 2 years after reswitch to agalsidase-β 1.0 mg/kg/eow.

Conclusion

Partial clearance, reaccumulation and renewed partial clearance of podocyte GL3 deposits in serial kidney biopsies over 8-10 years were seen in parallel with agalsidase dose adjustments. Repeated kidney biopsies may impact therapeutic choices in Fabry disease.

Phenotype, disease severity and pain are major determinants of quality of life in Fabry disease: results from a large multicenter cohort study

Quality of life (QoL) is decreased in patients with Fabry disease (FD). To improve QoL, it is important to understand the influence of FD related characteristics, symptoms, and complications. In this retrospective cohort study we explored the effect of pain (measured by the Brief Pain Inventory), phenotype, treatment, and FD-related complications on QoL. QoL data of Fabry patients as assessed by the EuroQol five dimension questionnaire (EQ-5D) from two international centers of excellence were collected. The aim of this study was to evaluate the effect of sex, phenotype, age, different states of disease severity, pain, and ERT on EQ-5D utilities. For 286 adult FD patients (mean age 42.5 years, 40% men, 60% classical phenotype) 2240 EQ-5Ds were available. QoL is decreased in men as well as women with FD, especially in older men with a classical phenotype. At age 50, utility was lower in men with classical FD compared to those with non-classical disease (β = -0.12, 95% CI: -0.23 - 0.01, p = 0.037) with further difference in the years thereafter. Cardiovascular complications, stroke or transient ischemic attacks, multiple FD-related complications and pain were also associated with decreased utilities. Overall, no change in utility was seen in patients on ERT over a mean follow-up of 6.1 years. FD leads to a decreased QoL compared to the general population. Disease complications and pain both negatively influence QoL. Adequate assessment and treatment of pain as well as improved strategies to prevent disease complications are needed to improve QoL in the FD population.

Causally treatable, hereditary neuropathies in Fabry's disease, transthyretin-related familial amyloidosis, and Pompe's disease

OBJECTIVES

Most acquired neuropathies are treatable, whereas genetic neuropathies respond to treatment in Fabry's disease (FD), transthyretin-related familial amyloidosis (TTR-FA), and Pompe's disease (PD). This review summarizes and discusses recent findings and future perspectives concerning etiology, pathophysiology, clinical presentation, diagnosis, treatment, and outcome of neuropathy in FD, TTR-FA, and PD.

METHODS

Literature review.

RESULTS

Neuropathy in FD concerns particularly small, unmyelinated, or myelinated sensory fibers (small fiber neuropathy [SFN]) and autonomic fibers, manifesting as acroparesthesias, Fabry's crises, or autonomous disturbances. FD neuropathy benefits from agalsidase alpha (0.2 mg/kg every second week intravenously) or from beta (1.0 mg/kg every second week intravenously). Neuropathy in TTR-FA is axonal and affects large and small sensory, motor, and autonomous fibers. Neuropathy in TTR-FA profits from liver transplantation and the TTR kinetic stabilizer tafamidis (20 mg/d). Neuropathy in PD particularly occurs in late-onset PD and manifests as mononeuropathy, polyneuropathy, or SFN. PD neuropathy presumably responds to alglucosidase-alpha (20 mg/kg every second week intravenously).

CONCLUSIONS

Neuropathy in FD, TTR-FA, and PD is predominantly a SFN and can be the dominant feature in FD and TTR-FA. SFN in FD, TTR-FA, and PD needs to be recognized and benefits from enzyme replacement treatment or TT-kinetic stabilizers.

Treatment of Depression in Adults with Fabry Disease

Fabry disease (FD) is a genetic X-linked, multisystemic, progressive lysosomal storage disorder (LSD). Depression has emerged as a disease complication, with prevalence estimates ranging from 15 to 62%. This is a pilot study examining the effects of psychological counseling for depression in FD on depression, adaptive functioning (AF), quality of life (QOL), and subjective pain experience. Telecounseling was also piloted, as it has beneficial effects in other chronic diseases which make in-person counseling problematic. Subjects completed 6 months of in-person or telecounseling with the same health psychologist, followed by 6 months without counseling. Self-report measures of depression, AF, QOL, and subjective pain were completed every 3 months. All subjects experienced improvements in depression, which were sustained during the follow-up period. Improvements in depression were correlated with improvements in mental health QOL and subjective pain severity, while improvements in mental health QOL were correlated with improvements in AF. While statistical comparison between counseling modes was not possible with the given sample size, relevant observations were noted. Recommendations for future research include replication of results with a larger sample size and a longer counseling period. The use of video counseling may be beneficial. In conclusion, the present pilot study supports the efficacy of psychological treatment for depression in people with FD, highlighting the importance of having health psychologists housed in LSD treatment centers, rather than specialty psychology/psychiatry settings, to increase participation and decrease potential obstacles to access due to perceived stigma.

Fabry Disease: A Disorder of Childhood Onset

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

The Psychosocial Impact of Fabry Disease on Pediatric Patients

Fabry disease (FD) is a multisystemic disease that has previously been reported to result in poorer quality of life and psychosocial functioning in impacted adults. However, prior to the current study, limited data were available on the impact of FD in children and adolescents. Therefore, the present study examined the differences of quality of life, psychosocial functioning, and depression in children with FD as compared with a healthy sample. Results indicated that children with FD were experiencing poorer quality of life than their healthy counterparts. Notably, results consistently identified adolescents with FD as more heavily impacted than younger children, although not to the same degree as adults with FD as reported in previous studies. Therefore, adolescence may be a critical point in the development of individuals with FD during which effective multidisciplinary interventions could be utilized to prevent poor quality of life and psychosocial functioning in adulthood.

Quality of life in patients with Fabry disease: a systematic review of the literature

Fabry disease (FD), caused by deficiency of the lysosomal enzyme α-galactosidase-A, is a progressive multisystem disease. The disease is X-linked with generally more severe manifestations in males, but can impact on quality of life (QoL) of both male and female patients. The purpose of this literature review is to analyse the currently available data concerning QoL measurement, specifically which questionnaires have been used to measure QoL, how patients with FD score compared to the general population, and the effects of enzyme replacement therapy (ERT) on QoL. Fifty-four articles were relevant for this literature review. Patients with FD had a lower QoL compared to the general population. No definite conclusions could be drawn from the studies on the effect of ERT on QoL; natural history data is scarce, changes observed were limited and the cohorts were of small size. We propose that a FD specific questionnaire be made to accurately assess QoL in patients with FD.

Fabry disease mimicking multiple sclerosis: Lessons from two case reports

Fabry disease is an X-linked lysosomal storage disorder that can mimic multiple sclerosis. We present two cases of heterozygous adult women where clinical and radiological features initially suggested a diagnosis of multiple sclerosis. This led us to review the early clinical course and neurological features of Fabry disease and highlight the importance of assessing non-neurologic (systemic) symptoms when considering a diagnosis of multiple sclerosis and the need for specialist interpretation of neuroradiological findings.

Psychological health in adults with morquio syndrome

Mucopolysaccharidosis type IV (MPSIV), also known as Morquio syndrome, is a progressive genetic condition which predominantly affects skeletal development. Research thus far has focused on physical manifestations, with little attention to psychological characteristics. As a first step in determining the natural occurrence of psychological symptoms in this population, we administered Achenbach measures of psychological functioning (ASEBA ASR and OASR), quality of life (SF-36), and pain severity (BPI) questionnaires to 20 adults with Morquio syndrome. 11/20 subjects (55%) scored within the symptomatic range on at least one or more ASEBA problem scales. These subjects also had higher pain severity scores (p = 0.051) and pain interference scores (p = 0.03) on the BPI. However, subjects with psychological symptoms did not differ significantly on QOL measures from those without psychological symptoms. Overall, subjects scored below the US mean only in physical health QOL (p < 0.001) on the SF-36, not mental health QOL. Implications of this study include the need for greater attention to psychological health in persons with Morquio syndrome, including regular assessment for psychological symptoms in addition to the quality of life measures typically used, as the latter may miss important information. Greater attention to psychological symptoms may help maximize overall health in adults with Morquio syndrome. Comparison with psychological studies on other lysosomal storage diseases suggests these results may be disease specific, rather than the result of living with chronic pain or having an LSD in general.

Kidney function as an underestimated factor for reduced health related quality of life in patients with Fabry disease

Background

Impairments of health related quality of life (HRQoL) are frequently observed in Fabry disease (FD) and are known to be related to neuropathic pain and cardiovascular events. This study aimed to explore the role of chronic kidney disease (CKD) in a large cohort of patients with FD.

Methods

In 96 patients (53% female; age 40 ± 12 yrs) with genetically proven FD, HRQoL was assessed by the Medical Outcomes Study (SF-36) questionnaire. All patients were naïve to enzyme replacement therapy. Three categories for kidney dysfunction were chosen, eGFR ≥/<60 ml/min/1.73 m² or need of renal replacement therapy (RRT). Minor (e.g. arrhythmia, angina pectoris, etc.) and major (e.g. myocardial infarction, coronary artery bypass, stroke or implantable cardioverter-defibrillator) vascular events as well as pain and pain therapy were considered in linear regression analyses with the dimensions of HRQoL.

Results

Ten patients (10%) had impaired kidney function and a further nine were on RRT (9.4%). Kidney function and pain emerged as the main factors associated with lower scores on the SF 36, in particular on physical components (PCS beta-coefficients for CKD −6.2, for RRT −11.8, for pain −9.1, p < 0.05, respectively), while controlling for gender, vascular event and pain-therapy. Relationships were found for mental aspects of HRQoL. Age and history of vascular events were not related to HRQoL.

Conclusion

Cardiovascular events and pain are important factors related to HRQoL, social functioning and depression. Our study highlights impaired chronic kidney disease, in particular after initiation of RRT, as a strong determinant of reduced HRQoL in FD.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2369-15-188) contains supplementary material, which is available to authorized users.

Gene therapy for fabry disease: a review of the literature

Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency of the lysosomal enzyme, α-galactosidase A. The lack of adequate enzymatic activity results in a systemic accumulation of neutral glycosphingolipids, predominantly globotriaosylceramide, in the lysosomes of, especially, endothelial and smooth muscle cells of blood vessels. Enzyme replacement therapy is at present the only available specific treatment for Fabry disease; however, this therapy has important drawbacks. Gene-mediated enzyme replacement is a reasonable and highly promising approach for the treatment of Fabry disease. It corresponds to a single gene disorder in which moderately low levels of enzyme activity should be sufficient for clinical efficacy and, thanks to cross-correction mechanisms, the transfection of a small number of cells will potentially correct distant cells too. This article summarizes the studies that have been carried out concerning gene therapy for the treatment of Fabry disease. We briefly review the literature from earlier studies in the 1990s to the current achievements.

A randomised, double-blind, placebo-controlled, crossover study to assess the efficacy and safety of three dosing schedules of agalsidase alfa enzyme replacement therapy for Fabry disease

Anecdotal reports suggest that the currently approved dosing interval of agalsidase alfa (0.2 mg/kg/2 weeks) for Fabry disease treatment is too long. This randomised, double-blind, placebo-controlled, crossover study investigated three altered dosing intervals. 18 Fabry patients received three agalsidase alfa dosing schedules, each for four weeks (A: 0.2 mg/kg∗2 weeks, B: 0.1 mg/kg/week, C: 0.2 mg/kg/week). Health state, pain levels, sweat volume and latency and plasma and urinary globotriaosylceramide levels were recorded throughout the study. No significant differences were found among the schedules for the primary efficacy outcome of self-assessed health state, or for pain scores. A trend toward increased sweat volume on QSART testing, and reduced urine globotriaosylceramide concentration were seen with treatment schedule C. Agalsidase alfa was safe and well tolerated with all schedules. In conclusion, the primary analyses did not find weekly infusions of agalsidase alfa to be statistically better than the approved dosing schedule however the data indicates that further studies with more patients over a longer period are required to more accurately determine the optimum dose and schedule.

Cost-effectiveness of enzyme replacement therapy for Fabry disease

Background

The cost-effectiveness of enzyme replacement therapy (ERT) compared to standard medical care was evaluated in the Dutch cohort of patients with Fabry disease.

Methods

Cost-effectiveness analysis was performed using a life-time state-transition model. Transition probabilities, effectiveness data and costs were derived from retrospective data and prospective follow-up of the Dutch study cohort consisting of males and females aged 5–78 years. Intervention with ERT (either agalsidase alfa or agalsidase beta) was compared to the standard medical care. The main outcome measures were years without end organ damage (renal, cardiac en cerebrovascular complications), quality adjusted life years (QALYs), and costs.

Results

Over a 70 year lifetime, an untreated Fabry patient will generate 55.0 years free of end-organ damage (53.5 years in males, 56.9 years in females) and 48.6 QALYs (47.8 in males, 49.7 in females). Starting ERT in a symptomatic patient increases the number of years free of end-organ damage by 1.5 year (1.6 in males, 1.3 in females), while the number of QALYs gained increases by a similar amount (1.7 in males, 1.4 in females). The costs of ERT starting in the symptomatic stage are between €9 - €10 million (£ 7.9 - £ 8.8 million, $13.0- $14.5 million) during a patient’s lifetime. Consequently, the extra costs per additional year free of end-organ damage and the extra costs per additional QALY range from €5.5 - €7.5 million (£ 4.8 – £ 6.6 million, $ 8.0 – $ 10.8 million), undiscounted.

Conclusions

In symptomatic patients with Fabry disease, ERT has limited effect on quality of life and progression to end organ damage. The pharmaco-economic evaluation shows that this modest effectiveness drives the costs per QALY and the costs per year free of end-organ damage to millions of euros. Differentiation of patients who may benefit from ERT should be improved to enhance cost-effectiveness.

Effectiveness of a calcium sodium phosphosilicate-containing prophylaxis paste in reducing dentine hypersensitivity immediately and 4 weeks after a single application: a double-blind randomized controlled trial

Aims

The aim of this single-site, randomized, controlled, double-blind, 3-arm parallel study was to determine the effectiveness of a prophylaxis paste containing 15% calcium sodium phosphosilicate (CSPS; NovaMin®) with and without fluoride in reducing dentine hypersensitivity immediately after a single application and 28 days following dental scaling and root planing.

Materials & Methods

Overall, 151 subjects were enrolled in this study. All subjects received a scaling and root planing procedure followed by a final prophylaxis step using one of three different prophylaxis pastes: Test-A (15% NovaMin® and NaF), Test-B (15% NovaMin®) and a control. Dentine hypersensitivity was assessed by tactile stimulus (Yeaple Probe®) and by air blast (Schiff scale) at baseline, immediately after and 28 days after a prophylaxis procedure. One hundred and forty-nine subjects completed the study.

Results

Subjects having received the test prophylaxis pastes showed statistically lower (anova, p < 0.05) dentine hypersensitivity compared with the control group immediately after the prophylaxis procedure (Yeaple Probe®: Test-A = 20.9 ± 12.6, Test-B = 22.7 ± 12.9, Control=11.2 ± 3.1; Schiff score: Test-A = 1.1 ± 0.6, Test-B = 1.1 ± 0.6, Control = 2.0 ± 0.7) and after 28 days (Yeaple probe: Test-A = 21.5 ± 11.9, Test-B = 20.6 ± 11.3, Control = 11.8 ± 6.0; Schiff score: Test-A = 1.0 ± 0.6, Test-B = 1.0 ± 0.6, Control = 2.0 ± 0.7).

Conclusions

In conclusion, the single application of both fluoridated and non-fluoridated prophylaxis pastes containing 15% CSPS (NovaMin®) provided a significant reduction of dentine hypersensitivity up to at least 28 days.

Management of painful neuropathies

Neuropathic pain is the most common type of pain in neuropathy. In painful polyneuropathies the pain usually has a "glove and stocking" distribution. The pain may be predominantly spontaneous, e.g., with a burning, pricking, or shooting character or characterized by evoked pain such as mechanical or cold allodynia. In the clinical setting, the prevention of painful neuropathies and treatment of underlying neuropathy remains inadequate and thus symptomatic treatment of the pain and related disability needs to be offered. Most randomized, double-blind, placebo-controlled trials (RCTs) published in painful neuropathy have been conducted in patients with diabetes and to what extent a treatment which is found effective in painful diabetic polyneuropathy can be expected to relieve other conditions like chemotherapy- or HIV-induced neuropathy is unknown. Tricyclic antidepressants (TCAs), gabapentin, pregabalin, and serotonin noradrenaline reuptake inhibitors (SNRIs) are first drug choices. In patients with localized neuropathic pain, a topical lidocaine patch may also be considered. Second-line treatments are tramadol and other opioids. New types of treatment include botulinum toxin type A (BTX-A), high-dose capsaicin patches, and cannabinoids. Other types of anticonvulsant drugs such as lamotrigine, oxcarbazepine, and lacosamide have a more questionable efficacy in painful polyneuropathy but may have an effect in a subgroup of patients. Combination therapy may be considered in patients with insufficient effect from one drug. Treatment is usually a trial-and-error process and has to be individualized to the single patient, taking into account all comorbidities such as possible concomitant depression, anxiety, diseases, and drug interactions. Side-effects to antidepressants include dry mouth, nausea, constipation, orthostatic hypotension, and sedation. ECG should always be obtained prior to treatment with TCAs, which also should not be used in patients with cardiac incompensation and epilepsy. The most common side-effects of gabapentin and pregabalin are CNS-related side-effects with dizziness and somnolence. Peripheral edema, weight gain, nausea, vertigo, asthenia, dry mouth, and ataxia may also occur. Topical treatments are better tolerated due to lack of systemic side-effects but there is still limited evidence for the long-term efficacy of these drugs. With available drugs, the average pain reduction is about 20-30%, and only 20-35% of the patients will achieve at least 50% pain reduction, which stresses the need of a multidisciplinary approach to pain treatment.

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.

Measuring patient experiences in Fabry disease: validation of the Fabry-specific Pediatric Health and Pain Questionnaire (FPHPQ)

Introduction

Common symptoms for children with Anderson-Fabry Disease (FD) such as acroparaesthesia and gastrointestinal manifestations can only be objectively assessed in patients using a valid instrument. To date, no such instrument exists.

Methods

A preliminary 40-item measure of symptoms and experience with FD, the Fabry-specific Paediatric Health and Pain Questionnaire (FPHPQ) was developed, but lacked a formal assessment of its measurement properties. The FPHPQ was used in the Fabry Outcome Survey (FOS), a registry for all patients with a confirmed diagnosis of FD who are receiving agalsidase alfa, or are treatment naïve and who are managed by physicians participating in FOS. After an item analysis to explore how items performed and combined into domains, a battery of psychometric analyses was performed to assess the measurement properties of this new instrument.

Results

Eighty-seven children (ages 4-18 years) completed the questionnaire. Twenty-three items in three subscales of the questionnaire emerged: pain associated with heat or exertion, pain associated with cold, and abdominal pain and fatigue symptoms. Internal consistency reliability for all three subscales was good (Cronbach alpha ≥ 0.84). Reliability was equally high for all age groups (4-7, 8-12, and 13-18). Test-retest reliability was high for all three subscales (intraclass correlation coefficient ≥ 0.74). Construct validity was demonstrated by moderate correlation with brief pain inventory (BPI), KINDL, and EQ-5D. Known group validity showed all subscales were able to discriminate between Fabry disease severity groups as classified by above or below median of the FOS MSSI (Mainz Severity Score Index) grade. The heat or exertion subscale was responsive to change in symptoms between responders and non-responders as defined by change in EQ-5D index scores between the first and second visit.

Conclusions

Preliminary results indicate that the measurement properties of FPHPQ are valid and reliable for assessing patient-reported symptoms of FD. The questionnaire could be a useful tool for clinicians to understand the progression of disease and monitor treatment effects. FPHPQ will be further validated and refined as the FOS registry is continuously adding more patients.

Neurological features of Fabry disease: clinical, pathophysiological aspects and therapy

Fabry disease is a multisystem, X-linked, lysosomal storage disorder caused by a mutation in the GLA gene on chromosome Xq22 resulting in alpha-galactosidase A enzyme (α-Gal A) deficiency. Neurological manifestations other than cerebrovascular accidents include small fibre neuropathy and dysautonomic disorders, which may be the presenting clinical features in a proportion of patients. An atypical disease onset may be misdiagnosed until the emergence of a more typical clinical picture, characterized by chronic renal and cardiac failure. Thus, neurologists should consider Fabry disease in differential diagnosis and provide an appropriate diagnostic work up. This review focuses on central and peripheral nervous system involving available diagnostic tools and diagnostic work up in Fabry disease. It also covers the most recent evidence regarding enzyme replacement therapy.

Inborn errors of metabolism: psychosocial challenges and proposed family systems model of intervention

Inborn errors of metabolism result in psychosocial crises that challenge individual and familial modes of functioning across the life cycle. Increased stress, mood disorders, interpersonal challenges, decreased quality of life, and grief reactions are all common for patients and their families. To effectively care for these patients, a holistic approach to their care, which incorporates their social context, is essential. Patients and their families need support as they focus on immediate practical demands, grieve over illness-related losses, and reorient future expectations. A family systems based model provides a flexible and individualized approach to care that allows for optimal psychosocial adjustment throughout the disease process.

Quality of life among polish Fabry patients — a cross-sectional study quality of life among polish Fabry patients

This study sought to explore the following issues 1) health-related quality of life (HRQoL) in Fabry patients relative to the general population 2) the quality of life (QoL) level in heterozygous females as compared to hemizygous males and the general population. A prospective, cross-sectional study was performed in patients diagnosed with Fabry disease in Poland (n=33). HRQoL was assessed with two generic questionnaires: the Medical Outcomes Study Short Form-36 (SF-36) and EuroQol questionnaire (EQ-5D), which includes the EQ-5D descriptive system and the EQ-visual analogue scale (EQ VAS), as well as a disease-specific author’s questionnaire. When measured with EQ-VAS, the subjective perception of health status was significantly lower in Fabry patients than that of the general population. SF-36 norm-based scores showed that patients are disadvantaged mainly in social functioning, bodily pain, and mental health. Objective assessments of HRQoL according to the EQ-5D Index tend to be lower for males than for females. Only male patients experienced extreme problems identified by the EQ-5D descriptive system. HRQoL of Fabry patients, measured by EQ-5D and SF-36, is lower as compared with that of the general population. Fabry disease effects QoL in its physical, mental and social dimensions.

Fabry disease in Spain: description of Spanish patients and a comparison with other European countries using data from the Fabry Outcome Survey (FOS)

AIMS

Fabry disease (FD) is an X-chromosome-linked transmitted lysosomal storage disorder as a result of the deficient activity of enzyme α-galactosidase A. This leads to accumulation of neutral glycosphingolipids associated with organ involvement and premature death. We report the clinical characteristics of Spanish patients enrolled on the Fabry Outcome Survey (FOS; an international multicentre registry for the disease) and also compare these data with those from the rest of Europe.

METHODS

Baseline clinical data of 92 patients (41 males and 51 females) are described and analysed globally and according to gender. We compare the data of Spanish patients with those previously published from the rest of Europe patients in FOS.

RESULTS

Mean age of onset of symptoms in men was 20, and 24 years in women, with a mean delay of 11 years to the diagnosis in both genders. The predominant clinical involvement in male patients was renal (69%), cardiac (66%) and neurological (60%), and for female patients, it was neurological (42%), cardiac (33%), keratopathy (30%) and nephropathy (28%). Disease severity was significantly higher in male patients. Compared to the rest of European FOS-patients, Spanish patients were diagnosed at an earlier age with a smaller proportion of disease-related involvement for most organ irrespective of gender, though not its global severity in male patients.

CONCLUSIONS

We present the largest cohort of Spanish patients diagnosed with FD. The pattern of involvement (though not its global severity) could be different in Spanish patients in comparison with others from Europe. Expanding the knowledge of FD will permit early diagnosis as well as the possibility of starting the specific treatment.

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.