Renal and multisystem effectiveness of 3.9 years of migalastat in a global real-world cohort: Results from the followME Fabry Pathfinders registry.

Fabry disease is a progressive, X-linked lysosomal disorder caused by reduced or absent α-galactosidase A activity due to GLA variants. The effects of migalastat were examined in a cohort of 125 Fabry patients with migalastat-amenable GLA variants in the followME Pathfinders registry (EUPAS20599), an ongoing, prospective, patient-focused registry evaluating outcomes for current Fabry disease treatments. We report annualised estimated glomerular filtration rate (eGFR) and Fabry-associated clinical events (FACEs) in a cohort of patients who had received ≥3 years of migalastat treatment in a real-world setting. As of August 2022, 125 patients (60% male) had a mean migalastat exposure of 3.9 years. At enrolment, median age was 58 years (males, 57; females, 60) with a mean eGFR of 83.7 mL/min/1.73 m2 (n = 122; males, 83.7; females, 83.8) and a median left ventricular mass index of 115.1 g/m2 (n = 61; males, 131.2; females, 98.0). Mean (95% confidence interval) eGFR annualised rate of change in the overall cohort (n = 116) was -0.9 (-10.8, 9.9) mL/min/1.73 m2/year with a similar rate of change observed across patients with varying levels of kidney function at enrolment. Despite population age and baseline morbidity, 80% of patients did not experience a FACE during the mean 3.9 years of migalastat exposure. The incidence of renal, cardiac, and cerebrovascular events was 2.0, 83.2, and 4.1 events per 1000 patient-years, respectively. These data support a role of migalastat in preserving renal function and multisystem effectiveness during ≥3 years of migalastat treatment in this real-world Fabry population.

Gene therapy for Fabry disease: Progress, challenges, and outlooks on gene-editing.

Gene therapy is the delivery of a therapeutic gene for endogenous cellular expression with the goal of rescuing a disease phenotype. It has been used to treat an increasing number of human diseases with many strategies proving safe and efficacious in clinical trials. Gene delivery may be viral or non-viral, performed in vivo or ex vivo, and relies on gene integration or transient expression; all of these techniques have been applied to the treatment of Fabry disease. Fabry disease is a genetic disorder of the α-galactosidase A gene, GLA, that causes an accumulation of glycosphingolipids in cells leading to cardiac, renal and cerebrovascular damage and eventually death. Currently, there are no curative treatments available, and the therapies that are used have significant drawbacks. These treatment concerns have led to the advent of gene therapies for Fabry disease. The first Fabry patients to receive gene therapy were treated with recombinant lentivirus targeting their hematopoietic stem/progenitor cells. Adeno-associated virus treatments have also begun. Alternatively, the field of gene-editing is a new and rapidly growing field. Gene-editing has been used to repair disease-causing mutations or insert genes into cellular DNA. These techniques have the potential to be applied to the treatment of Fabry disease provided the concerns of gene-editing technology, such as safety and efficiency, were addressed. This review focuses on the current state of gene therapy as it is being developed for Fabry disease, including progresses and challenges as well as an overview of gene-editing and how it may be applied to correct Fabry disease-causing mutations in the future.

Independent Registries Are Cost-Effective Tools to Provide Mandatory Postauthorization Surveillance for Orphan Medicinal Products.

OBJECTIVES: Orphan medicinal products (OMPs) often receive market authorization under conditions imposed by regulators for ongoing postauthorization surveillance (PAS) to answer questions that remain at the time of market entry. This surveillance may be provided through industry-funded registries (IFRs). Nevertheless, data in these registries may not be of sufficient quality to answer these questions and may not always be accessible for regulatory review. We propose that a mandatory independent registry is an efficient and cost-effective tool for PAS for OMPs. METHODS: Using data from the Canadian Fabry Disease Initiative, we reviewed costs per unique patient from sites participating in both the independent national registry and IFRs for Fabry disease and compared data completeness from the Canadian Fabry Disease Initiative to that in published documents from IFRs. RESULTS: The costs of data collection through the independent registry were 17% to 36% (depending on site) lower than costs to collect data in the IFRs, and completeness of data collected through the independent registry was higher than that through the IFRs. Data from the independent registry were reviewed annually to guide indications for publicly funded Fabry disease therapy. Even when enrollment ceased to be a requirement to receive therapy, 77% of patients continued to enroll in the registry, suggesting the structure was acceptable to patients. CONCLUSIONS: Independent registries are cost-effective and efficient tools and should be mandated by regulatory agencies as the preferred tool for PAS for OMPs. Countries with publicly funded health systems should consider investment in registry infrastructure for OMPs.

Tetrahydrobiopterin deficiency in the pathogenesis of Fabry disease.

Fabry disease is caused by deficient activity of α-galactosidase A and subsequent accumulation of glycosphingolipids (mainly globotriaosylceramide, Gb3), leading to multisystem organ dysfunction. Oxidative stress and nitric oxide synthase (NOS) uncoupling are thought to contribute to Fabry cardiovascular diseases. We hypothesized that decreased tetrahydrobiopterin (BH4) plays a role in the pathogenesis of Fabry disease. We found that BH4 was decreased in the heart and kidney but not in the liver and aorta of Fabry mice. BH4 was also decreased in the plasma of female Fabry patients, which was not corrected by enzyme replacement therapy (ERT). Gb3 levels were inversely correlated with BH4 levels in animal tissues and cultured patient cells. To investigate the role of BH4 deficiency in disease phenotypes, 12-month-old Fabry mice were treated with gene transfer-mediated ERT or substrate reduction therapy (SRT) for 6 months. In the Fabry mice receiving SRT but not ERT, BH4 deficiency was restored, concomitant with ameliorated cardiac and renal hypertrophy. Additionally, glutathione levels were decreased in Fabry mouse tissues in a sex-dependent manner. Renal BH4 levels were closely correlated with glutathione levels and inversely correlated with cardiac and kidney weight. In conclusion, this study showed that BH4 deficiency occurs in Fabry disease and may contribute to the pathogenesis of the disease through oxidative stress associated with a reduced antioxidant capacity of cells and NOS uncoupling. This study also suggested dissimilar efficacy of ERT and SRT in correcting pre-existing pathologies in Fabry disease.

Agalsidase alfa versus agalsidase beta for the treatment of Fabry disease: an international cohort study.

BACKGROUND: Two recombinant enzymes (agalsidase alfa 0.2 mg/kg/every other week and agalsidase beta 1.0 mg/kg/every other week) have been registered for the treatment of Fabry disease (FD), at equal high costs. An independent international initiative compared clinical and biochemical outcomes of the two enzymes. METHODS: In this multicentre retrospective cohort study, clinical event rate, left ventricular mass index (LVMI), estimated glomerular filtration rate (eGFR), antibody formation and globotriaosylsphingosine (lysoGb3) levels were compared between patients with FD treated with agalsidase alfa and beta at their registered dose after correction for phenotype and sex. RESULTS: 387 patients (192 women) were included, 248 patients received agalsidase alfa. Mean age at start of enzyme replacement therapy was 46 (±15) years. Propensity score matched analysis revealed a similar event rate for both enzymes (HR 0.96, P=0.87). The decrease in plasma lysoGb3 was more robust following treatment with agalsidase beta, specifically in men with classical FD (ß: -18 nmol/L, P<0.001), persisting in the presence of antibodies. The risk to develop antibodies was higher for patients treated with agalsidase beta (OR 2.8, P=0.04). LVMI decreased in a higher proportion following the first year of agalsidase beta treatment (OR 2.27, P=0.03), while eGFR slopes were similar. CONCLUSIONS: Treatment with agalsidase beta at higher dose compared with agalsidase alfa does not result in a difference in clinical events, which occurred especially in those with more advanced disease. A greater biochemical response, also in the presence of antibodies, and better reduction in left ventricular mass was observed with agalsidase beta.

Screening, diagnosis, and management of patients with Fabry disease: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference.

Patients with Fabry disease (FD) are at a high risk for developing chronic kidney disease and cardiovascular disease. The availability of specific but costly therapy has elevated the profile of this rare condition. This KDIGO conference addressed controversial areas in the diagnosis, screening, and management of FD, and included enzyme replacement therapy and nonspecific standard-of-care therapy for the various manifestations of FD. Despite marked advances in patient care and improved overall outlook, there is a need to better understand the pathogenesis of this glycosphingolipidosis and to determine the appropriate age to initiate therapy in all types of patients. The need to develop more effective specific therapies was also emphasized.

Chronic kidney disease and an uncertain diagnosis of Fabry disease: approach to a correct diagnosis.

BACKGROUND AND OBJECTIVES: Screening for Fabry disease (FD), an X-linked lysosomal storage disorder, reveals a significant number of individuals with a genetic variant of unknown significance without classical FD manifestations; these variants in the α-galactosidase A gene often result in a high residual leukocyte α-galactosidase A and it is unclear whether these individuals suffer from FD. Therefore, a structured diagnostic approach is warranted. We present a diagnostic algorithm on how to approach adults with chronic kidney disease and an uncertain diagnosis of FD nephropathy. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: A modified Delphi procedure was conducted to reach consensus among 11 FD experts. A systematic review was performed to identify possible criteria that could confirm or exclude FD nephropathy. RESULTS: The gold standard for FD nephropathy was defined as characteristic storage on electron microscopy (EM) in a kidney biopsy in the absence of medication that may induce similar storage. The suggested criteria to confirm FD nephropathy are as follows: 'renal cysts', 'Maltese cross sign', 'immunohistochemical staining of Gb3 in urine' and 'high urinary Gb3'; and to exclude FD nephropathy: 'absence of renal cysts', 'small kidneys' and 'high protein excretion' were rejected because of low or uncertain specificity. Urinary Gb3 may be increased in other kidney diseases and there was no agreement on this criterion, although a third of the panel indicated that it is sufficient to diagnose FD nephropathy. The 'Maltese cross sign' and 'high urinary Gb3' were selected as red flags to suggest the possibility of FD nephropathy, but are not sufficient for a definite diagnosis of FD nephropathy. CONCLUSIONS: In adults with chronic kidney disease, an α-galactosidase A gene variant and an uncertain diagnosis of FD, a kidney biopsy with EM analysis should be performed to confirm or reject the diagnosis of FD nephropathy. Other criteria currently cannot substitute for a biopsy in these cases.

Fabry disease biomarkers in patients switched from enzyme-replacement therapy to migalastat oral chaperone therapy.

Background: A biomarker profile was evaluated longitudinally in patients with Fabry disease switched from enzyme-replacement therapy (ERT) to migalastat. Methods: 16 Gb3 isoforms and eight lyso-Gb3 analogues were analyzed in plasma and urine by LC-MS/MS at baseline and at three different time points in naive participants and participants switching from either agalsidase α or ß to migalastat. Results: 29 adult participants were recruited internationally (seven centers). The Mainz Severity Score Index and mean biomarker levels remained stable (p ≥ 0.05) over a minimum of 12 months compared with baseline following the treatment switch. Conclusion: In this cohort of patients with Fabry disease with amenable mutations, in the short term, a switch from ERT to migalastat did not have a marked effect on the average biomarker profile.

Safety and efficacy of pegunigalsidase alfa in patients with Fabry disease who were previously treated with agalsidase alfa: results from BRIDGE, a phase 3 open-label study.

BACKGROUND: Pegunigalsidase alfa is a novel, PEGylated α-galactosidase-A enzyme-replacement therapy approved in the EU and US to treat patients with Fabry disease (FD). OBJECTIVE/METHODS: BRIDGE is a phase 3 open-label, switch-over study designed to assess safety and efficacy of 12 months of pegunigalsidase alfa (1 mg/kg every 2 weeks) treatment in adults with FD who had been previously treated with agalsidase alfa (0.2 mg/kg every 2 weeks) for ≥ 2 years. RESULTS: Twenty-seven patients were screened; 22 met eligibility criteria; and 20 (13 men, 7 women) completed the study. Pegunigalsidase alfa was well-tolerated, with 97% of treatment-emergent adverse events (TEAEs) being of mild or moderate severity. The incidence of treatment-related TEAEs was low, with 2 (9%) discontinuations due to TEAEs. Five patients (23%) reported infusion-related reactions. Overall mean (SD; n = 22) baseline estimated glomerular filtration rate (eGFR) was 82.5 (23.4) mL/min/1.73 m2 and plasma lyso-Gb3 level was 38.3 (41.2) nmol/L (men: 49.7 [45.8] nmol/L; women: 13.8 [6.1] nmol/L). Before switching to pegunigalsidase alfa, mean (standard error [SE]) annualized eGFR slope was - 5.90 (1.34) mL/min/1.73 m2/year; 12 months post-switch, the mean eGFR slope was - 1.19 (1.77) mL/min/1.73 m2/year; and mean plasma lyso-Gb3 reduced by 31%. Seven (35%) out of 20 patients were positive for pegunigalsidase alfa antidrug antibodies (ADAs) at ≥ 1 study timepoint, two of whom had pre-existing ADAs at baseline. Mean (SE) changes in eGFR slope for ADA-positive and ADA-negative patients were + 5.47 (3.03) and + 4.29 (3.15) mL/min/1.73 m2/year, respectively, suggesting no negative impact of anti-pegunigalsidase alfa ADAs on eGFR slope. CONCLUSION: Pegunigalsidase alfa may offer a safe and effective treatment option for patients with FD, including those previously treated with agalsidase alfa. TRN: NCT03018730. Date of registration: January 2017.

Persistent hematopoietic polyclonality after lentivirus-mediated gene therapy for Fabry disease.

The safety and efficacy of lentivirus-mediated gene therapy was recently demonstrated in five male patients with Fabry disease-a rare X-linked lysosomal storage disorder caused by GLA gene mutations that result in multiple end-organ complications. To evaluate the risks of clonal dominance and leukemogenesis, which have been reported in multiple gene therapy trials, we conducted a comprehensive DNA insertion site analysis of peripheral blood samples from the five patients in our gene therapy trial. We found that patients had a polyclonal integration site spectrum and did not find evidence of a dominant clone in any patient. Although we identified vector integrations near proto-oncogenes, these had low percentages of contributions to the overall pool of integrations and did not persist over time. Overall, we show that our trial of lentivirus-mediated gene therapy for Fabry disease did not lead to hematopoietic clonal dominance and likely did not elevate the risk of leukemogenic transformation.

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

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

Do clinical guidelines facilitate or impede drivers of treatment in Fabry disease?

BACKGROUND: Variable disease progression confounds accurate prognosis in Fabry disease. Evidence supports the long-term benefit of early intervention with disease-specific therapy, but current guidelines recommend treatment initiation based on signs that may present too late to avoid irreversible organ damage. Findings from the 'PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease' (PREDICT-FD) initiative included expert consensus on 27 early indicators of disease progression in Fabry disease and on drivers of and barriers to treatment initiation in Fabry disease. Here, we compared the PREDICT-FD indicators with guidance from the European Fabry Working Group and various national guidelines to identify differences in signs supporting treatment initiation and how guidelines themselves might affect initiation. Finally, anonymized patient histories were reviewed by PREDICT-FD experts to determine whether PREDICT-FD indicators supported earlier treatment than existing guidance. RESULTS: Current guidelines generally aligned with PREDICT-FD on indicators of renal involvement, but most lacked specificity regarding cardiac indicators. The prognostic significance of neurological indicators such as white matter lesions (excluded by PREDICT-FD) was questioned in some guidelines and excluded from most. Some PREDICT-FD patient-reported signs (e.g., febrile crises) did not feature elsewhere. Key drivers of treatment initiation in PREDICT-FD were: (A) male sex, young age, and clinical findings (e.g., severe pain, organ involvement), (B) improving clinical outcomes and preventing disease progression, and (C) a family history of Fabry disease (especially if outcomes were severe). All guidelines aligned with (A) and several advocated therapy for asymptomatic male patients. There was scant evidence of (B) in current guidance: for example, no countries mandated ancillary symptomatic therapy, and no guidance advocated familial screening with (C) when diagnosis was confirmed. Barriers were misdiagnosis and a lack of biomarkers to inform timing of treatment. Review of patient histories generally found equal or greater support for treatment initiation with PREDICT-FD indicators than with other guidelines and revealed that the same case and guideline criteria often yielded different treatment recommendations. CONCLUSIONS: Wider adoption of PREDICT-FD indicators at a national level could promote earlier treatment in Fabry disease. Clearer, more concise guidance is needed to harmonize treatment initiation in Fabry disease internationally.

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.

Primary Hyperoxaluria Type 1 (PH1) Presenting With End-Stage Kidney Disease and Cutaneous Manifestations in Adulthood: A Case Report.

RATIONALE: Primary hyperoxaluria (PH) is a rare autosomal recessive disorder more commonly diagnosed in children or adolescents. Owing to its rarity and heterogeneous phenotype, it is often underrecognized, resulting in delayed diagnosis, including diagnosis after end-stage kidney disease (ESKD) has occurred or recurrence after kidney-only transplantation. CASE PRESENTATION: A 40-year-old Caucasian Canadian woman with a history of recurrent nephrolithiasis since age 19 presented with ESKD and cutaneous symptoms. She had no known prior kidney disease and no family history of kidney disease or nephrolithiasis. DIAGNOSIS: A diagnosis of primary hyperoxaluria type 1 (PH1) due to homozygous splice donor mutation (AGXT c.680+1G>A) was made with kidney and cutaneous pathology demonstrating calcium oxalate deposition and ultrasound suggestive of nephrocalcinosis. INTERVENTIONS: She was initiated on frequent, high-efficiency, high-flux conventional hemodialysis and oral pyridoxine. Lumasiran was added 11 months later, after she developed bilateral swan-neck deformities. OUTCOMES: After 14 months of high-intensity dialysis and 3 months of lumasiran, there have been no signs of renal recovery, and extra-renal involvement has increased with progressive swan-neck deformities, reduced cardiac systolic function, and pulmonary hypertension. The patient has been waitlisted for kidney-liver transplantation. TEACHING POINTS: This case report describes an adult presentation of PH1. The case highlights the importance of timely workup of metabolic causes of recurrent nephrolithiasis or nephrocalcinosis in adults which can be a presenting sign of PH and genetic testing for PH to facilitate early diagnosis and treatment especially in the era of novel therapeutics that may alter disease course and outcomes. The case also demonstrates the value of testing for PH in adults presenting with unexplained ESKD and a history of recurrent nephrolithiasis or nephrocalcinosis due to implications for organ transplantation strategy and presymptomatic family screening.

JUSTIFICATION: L'hyperoxalurie primaire (HP) est un trouble récessif autosomique rare plus souvent rencontré chez les enfants ou les adolescents. En raison de sa rareté et de son phénotype hétérogène, cette affection est fréquemment sous-reconnue, ce qui entraîne un retard dans le diagnostic, et ce, même après l'apparition d'une insuffisance rénale terminale (IRT) ou une récidive suivant une greffe simple de rein. PRÉSENTATION DU CAS: Nous présentons le cas d'une Canadienne de race blanche âgée de 40 ans avec des antécédents de néphrolithiase récurrente depuis l'âge de 19 ans. La patiente était atteinte d'IRT et présentait des symptômes cutanés. Elle n'avait aucun antécédent connu de maladie rénale ou antécédent familial de maladie rénale ou de néphrolithiase. DIAGNOSTIC: Une pathologie rénale et cutanée montrant des dépôts d'oxalate de calcium et une échographie suggérant une néphrocalcinose ont permis de poser un diagnostic d'hyperoxalurie primaire de type 1 (HP1) due à une mutation de donneur d'épissage homozygote (AGXT c.680+1G>A). INTERVENTIONS: La patiente a amorcé des traitements d'hémodialyse conventionnelle à grande fréquence, à haut rendement et à flux élevé, et a reçu de la pyridoxine par voie orale. Un traitement par lumasiran a été ajouté 11 mois plus tard, après le développement de déformations bilatérales en col de cygne. RÉSULTATS: Après quatorze mois de dialyze à haute intensité et trois mois de lumasiran, aucun signe de récupération rénale n'a été observé. L'intervention d'épuration extra-rénale a été augmentée en raison de déformations progressives en col de cygne, d'une réduction de la fonction cardiaque systolique et d'une hypertension pulmonaire. La patiente a été placée sur la liste d'attente pour une transplantation rénale et hépatique. ENSEIGNEMENTS TIRÉS: Ce rapport de cas décrit une présentation adulte d'HP1. Ce cas souligne l'importance de traiter rapidement les causes métaboliques de la néphrolithiase ou de la néphrocalcinose récidivante chez les adultes, car celles-ci peuvent être des signes d'hyperoxalurie primaire (HP). Ce cas souligne en outre l'importance de procéder à des tests génétiques pour l'HP afin de permettre le diagnostic et le traitement précoces, en particulier à l'ère de nouveaux traitements susceptibles d'infléchir l'évolution et les résultats de la maladie. Enfin, il démontre la valeur du dépistage de l'HP chez les adultes présentant une IRT inexpliquée et des antécédents de néphrolithiase ou de néphrocalcinose récidivante, en raison de ses implications sur la stratégie de transplantation d'organes et sur le dépistage pré-symptomatique de la famille.

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

BACKGROUND AND OBJECTIVE: Fabry disease, an X-linked lysosomal storage disorder characterized by absent or reduced alpha-galactosidase activity, is a lifelong disease that impairs patients' quality of life. Patients with Fabry disease have a considerably shortened lifespan, with mortality being mainly due to renal failure, cardiovascular disease, or cerebrovascular disease. Enzyme replacement therapy with agalsidase alfa has been shown to attenuate the renal, cardiovascular, and neuropathic disease progression associated with Fabry disease. The objective of this study was to investigate the safety of a new animal component-free version of agalsidase alfa. METHODS: A phase III/IV, open-label, single-arm, multicenter safety study was conducted in Canadian patients with Fabry disease between August 2011 and September 2017 as a regulatory requirement to assess the safety of agalsidase alfa produced using an animal component-free bioreactor process. Eligible patients had a documented diagnosis of Fabry disease and satisfied current Canadian guidelines for receiving enzyme replacement therapy for Fabry disease. Following treatment with animal component-free bioreactor-processed agalsidase alfa, treatment-emergent adverse events were monitored, and post hoc analyses of infusion-related reactions by antidrug antibody and neutralizing antibody statuses were conducted. The data were analyzed using descriptive statistics. RESULTS: A total of 167 patients (mean [standard deviation] age, 48.9 [14.8] years), including six pediatric patients (< 18 years of age), received at least one full or partial infusion of agalsidase alfa animal component-free. Fewer than 5% of treatment-emergent adverse events (212/4446) observed in 40 patients were reported as infusion-related reactions. Antidrug antibody and neutralizing antibody status did not affect the proportion of patients with infusion-related reactions. No clinically significant changes in vital signs were observed in patients over the course of the study. CONCLUSIONS: Long-term treatment with bioreactor-produced agalsidase alfa animal component-free did not reveal new safety signals in this population of Canadian patients with Fabry disease. The treatment-emergent adverse event profile was consistent with the clinical manifestations of the disease and the known safety profile of roller bottle-produced agalsidase alfa. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01298141.

Lentivirus-mediated gene therapy for Fabry disease.

Enzyme and chaperone therapies are used to treat Fabry disease. Such treatments are expensive and require intrusive biweekly infusions; they are also not particularly efficacious. In this pilot, single-arm study (NCT02800070), five adult males with Type 1 (classical) phenotype Fabry disease were infused with autologous lentivirus-transduced, CD34+-selected, hematopoietic stem/progenitor cells engineered to express alpha-galactosidase A (α-gal A). Safety and toxicity are the primary endpoints. The non-myeloablative preparative regimen consisted of intravenous melphalan. No serious adverse events (AEs) are attributable to the investigational product. All patients produced α-gal A to near normal levels within one week. Vector is detected in peripheral blood and bone marrow cells, plasma and leukocytes demonstrate α-gal A activity within or above the reference range, and reductions in plasma and urine globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3) are seen. While the study and evaluations are still ongoing, the first patient is nearly three years post-infusion. Three patients have elected to discontinue enzyme therapy.

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.

Renal-Limited Antiglomerular Basement Membrane Disease Related To Alemtuzumab: A Case Report.

RATIONALE: Alemtuzumab is a monoclonal antibody approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Many autoimmune-mediated adverse events have been associated with alemtuzumab, including renal-limited anti-glomerular basement membrane (GBM) disease. PRESENTING CONCERN: A 52-year-old female with RRMS presented with acute kidney injury 39 months after receiving 1 cycle of alemtuzumab. She had a history of alemtuzumab-associated hypothyroidism and thrombocytopenia, urinary tract infections, and chronically abnormal urinalyses. DIAGNOSIS: A diagnosis of renal-limited anti-GBM disease was made based on renal biopsy and positive anti-GBM serology. Alemtuzumab was thought to be the trigger of the anti-GBM disease as there were no other exposures or serologic findings suggesting other causes. INTERVENTIONS: She was treated with corticosteroids, cyclophosphamide, and plasmapheresis. She required hemodialysis for acute renal failure. OUTCOMES: Despite treatment, the patient's renal function did not recover. She remained dialysis-dependent and anti-GBM antibody titers remained elevated 6 months after presentation. TEACHING POINTS: Anti-GBM disease is a life-altering adverse event that can be associated with alemtuzumab. Our case highlights the limitations of monitoring urinalyses as a trigger for anti-GBM antibody testing in patients who have received alemtuzumab and have baseline abnormal urinalyses; such patients may require further protocolized anti-GBM antibody testing, although the optimal frequency of such antibody screening remains unclear.

JUSTIFICATION: L'alemtuzumab est un anticorps monoclonal approuvé pour le traitement de la sclérose en plaque récurrente-rémittente (SPRR). De nombreux événements indésirables à médiation auto-immune ont été associés à ce traitement, notamment la glomérulonéphrite auto-immune (maladie anti-MBG). PRÉSENTATION DU CAS: Une femme de 52 ans atteinte de SPRR présentant une insuffisance rénale aiguë 39 mois après avoir reçu un cycle d'alemtuzumab. La patiente avait des antécédents d'hypothyroïdie et de thrombocytopénie liées à la prise d'alemtuzumab, en plus de présenter des tests urinaires anormaux et de souffrir d'infections des voies urinaires de façon chronique. DIAGNOSTIC: Un diagnostic de glomérulonéphrite auto-immune a été établi sur la base d'une biopsie rénale et d'une sérologie anti-MBG positive. On a suspecté l'alemtuzumab d'être à l'origine de la glomérulonéphrite auto-immune puisqu'aucun résultat sérologique ou exposition ne suggérait d'autres causes. INTERVENTIONS: La patiente a été traitée aux corticostéroïdes, au cyclophosphamide et par plasmaphérèse. L'insuffisance rénale aiguë a requis un traitement d'hémodialyse. RÉSULTATS: Malgré le traitement, la fonction rénale de la patiente ne s'est pas rétablie. La patiente a dû poursuivre les traitements de dialyse et ses titres d'anticorps demeuraient élevés six mois après la présentation des symptômes. LEÇONS TIRÉES: La glomérulonéphrite auto-immune est un événement indésirable aux conséquences dévastatrices et cette affection peut être associée à la prise d'alemtuzumab. Notre cas met en lumière les limites du suivi des analyses urinaires comme critère de dépistage des anticorps anti-MBG chez les patients ayant reçu de l'alemtuzumab et dont les analyses urinaires préalables sont anormales. Ces patients pourraient nécessiter des tests de détection des anticorps anti-MBG supplémentaires, bien que leur fréquence optimale demeure incertaine.