Identification of Safe and Effective Intravenous Dose of AAVrh.10hFXN to Treat the Cardiac Manifestations of Friedreich's Ataxia.

Friedreich's ataxia (FA) is a life-threatening autosomal recessive disorder characterized by neurological and cardiac dysfunction. Arrhythmias and heart failure are the main cause of premature death. From prior studies in murine models of FA, adeno-associated virus encoding the normal human frataxin gene (AAVrh.10hFXN) effectively treated the cardiac manifestations of the disease. However, the therapeutic dose window is limited by high level of human frataxin (hFXN) gene expression associated with toxicity. As a therapeutic goal, since FA heterozygotes have no clinical manifestations of FA, we estimated the level of frataxin (FXN) necessary to convert the heart of a homozygote to that of a heterozygote. In noncardiac cells, FA heterozygotes have 30-80% of normal FXN levels (17.7-47.2 ng/mg, average 32.5 ng/mg) and FA homozygotes 2-30% normal levels (1.2-17.7 ng/mg, average 9.4 ng/mg). Therefore, an AAV vector would need to augment endogenous in an FA homozygote by >8.3 ng/mg. To determine the required dose of AAVrh.10hFXN, we administered 1.8 × 1011, 5.7 × 1011, or 1.8 × 1012 gc/kg of AAVrh.10hFXN intravenously (IV) to muscle creatine kinase (mck)-Cre conditional knockout Fxn mice, a cardiac and skeletal FXN knockout model. The minimally effective dose was 5.7 × 1011 gc/kg, resulting in cardiac hFXN levels of 6.1 ± 4.2 ng/mg and a mild (p < 0.01 compared with phosphate-buffered saline controls) improvement in mortality. A dose of 1.8 × 1012 gc/kg resulted in cardiac hFXN levels of 33.7 ± 6.4 ng/mg, a significant improvement in ejection fraction and fractional shortening (p < 0.05, both comparisons) and a 21.5% improvement in mortality (p < 0.001). To determine if the significantly effective dose of 1.8 × 1012 gc/kg could achieve human FA heterozygote levels in a large animal, this dose was administered IV to nonhuman primates. After 12 weeks, the vector-expressed FXN in the heart was 17.8 ± 4.9 ng/mg, comparable to the target human levels. These data identify both minimally and significantly effective therapeutic doses that are clinically relevant for the treatment of the cardiac manifestations of FA.

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

PURPOSE: Fabry disease is a rare multisystemic disorder caused by functional deficiency of the lysosomal enzyme alpha-galactosidase A. Gastrointestinal (GI) signs and symptoms are among the earliest clinical manifestations in patients with Fabry disease but are often nonspecific, misdiagnosed, and untreated. No instruments have been developed specifically to assess GI signs and symptoms in Fabry disease. The FABry disease Patient-Reported Outcome-GastroIntestinal (FABPRO-GI) was developed to address this unmet need and is intended for use in clinical trials (24-h FABPRO-GI) and real-world settings (7-day FABPRO-GI). METHODS: Findings from a literature review, expert advisory meetings, and patient concept elicitation interviews (CEIs) were summarized into conceptual models. These conceptual models were used to develop preliminary versions of the 24-h and 7-day FABPRO-GI. Cognitive debriefing interviews (CDIs) were conducted with additional patients to assess content validity, including understandability, relevance, and comprehensiveness of the preliminary versions of the 24-h and 7-day FABPRO-GI. RESULTS: Literature review (n = 17 articles), expert advisory meetings (n = 5), and patient CEIs (n = 17) identified mostly overlapping Fabry disease-related GI signs and symptoms, including abdominal cramps, bloating, and diarrhea, and informed development of the preliminary 24-h and 7-day FABPRO-GI. CDIs (n = 15) provided evidence of content validity and informed revisions of the 24-h and 7-day FABPRO-GI. CONCLUSION: With evidence of content validity, the 24-h and 7-day FABPRO-GI are the first Fabry disease-specific patient-reported outcomes to assess GI signs and symptoms in patients with Fabry disease with potential for use in clinical trials and real-world settings, respectively.

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

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

Wound closure in epidermolysis bullosa: data from the vehicle arm of the phase 3 ESSENCE Study.

BACKGROUND: Chronic wounds are a fundamental issue for patients with epidermolysis bullosa (EB). Herein, we assess the natural history of wound closure in patients with EB who were randomly assigned to the vehicle-control arm of the multicenter, randomized, double-blind, phase 3 ESSENCE (NCT02384460) trial. METHODS: ESSENCE was designed to assess the efficacy and safety of a topical cream formulation of 6% allantoin (SD-101 6%) vs vehicle (SD-101 0%) in patients ≥1 month old who had a diagnosis of EB (simplex, recessive dystrophic, or intermediate junctional) and a target wound 10-50 cm2 present for ≥21 days. Time to complete target wound closure and the proportion of patients with target wound closure over time were analyzed overall and by parameters including patient age and baseline body surface area index (BSAi) of total wound burden (< 5% and ≥ 5%). Changes in BSAi of lesional skin, pain, and itching were also assessed. RESULTS: The vehicle-control arm included 87 patients. Mean (standard deviation [SD]) time to target wound closure within 3 months was 53.6 (28.6) days, with a range of 14 to 142 days. The proportion of patients with target wound closure increased over time from 7.1% at day 14 to 53.6% at month 3. Mean (SD) changes from baseline in BSAi of total wound burden and BSAi of lesional skin at month 3 were -2.3% (6.3) and -5.0% (13.5) of total body coverage, respectively. Reductions in pain and itching were observed at day 7 and maintained for 3 months. Faster healing times and a greater proportion of patients with wound closure were observed in patients aged 1 month to < 2 years; those with wounds < 30 days old, and in those with BSAi of total body wound burden < 5%. CONCLUSIONS: Treatment response observed in the vehicle-control arm of the ESSENCE study was unexpectedly high and may have been due to unforeseen benefits of vehicle or enhanced wound care provided by the clinical trial staff. These observations will help inform the study design of future trials in patients with EB. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02384460 ; Date of registration: February 13, 2015; First participant enrollment: March 11, 2015.

Efficacy and tolerability of the investigational topical cream SD-101 (6% allantoin) in patients with epidermolysis bullosa: a phase 3, randomized, double-blind, vehicle-controlled trial (ESSENCE study).

BACKGROUND: Epidermolysis bullosa (EB) is a rare genetic disorder that manifests as blistering and/or skin erosion. There is no approved treatment for EB; current standard of care consists of wound and pain management. SD-101 6% is a topical cream containing 6% allantoin that was developed for treating skin lesions in patients with EB. The aim of this phase 3, multicenter, randomized, double-blind, vehicle-controlled study was to assess the efficacy and safety of SD-101 6% cream versus vehicle (0% allantoin) on lesions in patients with EB. METHODS: Eligible patients were ≥1 month old, had a diagnosis of EB (simplex, recessive dystrophic, or intermediate junctional) and a target wound 10-50 cm2 in size that was present for ≥21 days. Patients were randomly assigned to SD-101 6% cream or vehicle, which was applied topically once a day to the entire body for 3 months. Primary efficacy endpoints were time to complete target wound closure within 3 months and the proportion of patients who experienced complete target wound closure within 3 months. Post hoc subgroup analyses were conducted by patient age and in those with body surface area index of total body wound burden ≥5% at baseline. RESULTS: In total, 169 patients were enrolled and randomly assigned to SD-101 6% (n = 82) or vehicle (n = 87). Baseline demographics and disease characteristics were similar between treatment groups. There were no statistically significant differences between treatment groups in time to target wound closure (hazard ratio, 1.004; 95% confidence interval [CI] 0.651, 1.549; P = 0.985) or proportion of patients with complete target wound closure within 3 months (odds ratio [95% CI], 0.733 [0.365, 1.474]; nominal P = 0.390). A positive trend toward faster wound closure with SD-101 6% versus vehicle was observed in patients aged 2 to <12 years and those with total body wound burden ≥5% at baseline. SD-101 6% cream was well tolerated. CONCLUSIONS: SD-101 6% cream for treatment of EB-associated lesions was not more effective than vehicle in shortening the time to complete target wound closure or achieving complete target wound closure within 3 months. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02384460; Date of trial registration, February 13, 2015; First participant enrolled, March 11, 2015.

Efficacy and safety of migalastat in a Japanese population: a subgroup analysis of the ATTRACT study.

BACKGROUND: Fabry disease is a progressive X-linked lysosomal disorder. In this subgroup analysis of the global phase III ATTRACT study, the efficacy and safety of oral migalastat, a pharmacologic chaperone, were investigated in Japanese patients with Fabry disease. METHODS: Patients were randomly assigned to receive migalastat (150 mg every other day) or to continue biweekly enzyme replacement therapy infusions (ERT; agalsidase alfa 0.2 mg/kg or agalsidase beta 1.0 mg/kg) for 18 months followed by a 12-month open-label extension during which all patients received migalastat. End points included glomerular filtration rate (estimated and measured), left ventricular mass index (LVMi), composite clinical outcomes, leukocyte alpha-galactosidase A activity, plasma globotriaosylsphingosine (lyso-Gb3), and safety. RESULTS: Data from 7 Japanese patients (migalastat, 5; ERT, 2), mean age 55 years, with high disease burden, were analyzed. All patients in the migalastat group completed the open-label comparison and extension periods. At 18 months, efficacy in the Japanese patient population was similar to that in the overall ATTRACT population. Migalastat treatment increased leukocyte alpha-galactosidase A activity, stabilized renal function, and decreased LVMi. Plasma lyso-Gb3 levels remained low and stable. Additionally, the long-term extension study showed that efficacy of migalastat was maintained for up to 48 months. Migalastat was safe and well tolerated in the Japanese patients, as in the overall ATTRACT population. CONCLUSION: Migalastat can be used to treat Japanese patients with Fabry disease with GLA mutations amenable to migalastat according to the dosage and administration approved in other countries. TRIAL REGISTRATION NUMBERS: ClinicalTrials.gov, NCT01218659 and NCT02194985.

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

PURPOSE: Outcomes in patients with Fabry disease receiving migalastat during the phase 3 FACETS trial (NCT00925301) were evaluated by phenotype. METHODS: Data were evaluated in two subgroups of patients with migalastat-amenable GLA variants: "classic phenotype" (n = 14; males with residual peripheral blood mononuclear cell α-galactosidase A <3% normal and multiorgan system involvement) and "other patients" (n = 36; males not meeting classic phenotype criteria and all females). Endpoints included estimated glomerular filtration rate (eGFR), left ventricular mass index (LVMi), Gastrointestinal Symptoms Rating Scale diarrhea subscale (GSRS-D), renal peritubular capillary (PTC) globotriaosylceramide (GL-3) inclusions, and plasma globotriaosylsphingosine (lyso-Gb3). RESULTS: Baseline measures in the classic phenotype patients suggested a more severe phenotype. At month 24, mean (SD) annualized change in eGFRCKD-EPI with migalastat was -0.3 (3.76) mL/min/1.73 m2 in the classic phenotype subgroup; changes in LVMi, GSRS-D, and lyso-Gb3 were -16.7 (18.64) g/m2, -0.9 (1.66), and -36.8 (35.78) nmol/L, respectively. At month 6, mean PTC GL-3 inclusions decreased with migalastat (-0.8) and increased with placebo (0.3); switching from placebo to migalastat, PTC inclusions decreased by -0.7. Numerically smaller changes in these endpoints were observed in the other patients. CONCLUSION: Migalastat provided clinical benefit to patients with Fabry disease and amenable variants, regardless of disease severity.

Pregnancy Outcome after Exposure to Migalastat for Fabry Disease: A Clinical Report.

Our patient was a 37-year-old woman with Fabry disease (GLA p.R112H) with a medical history of recurrent headache, nausea, vomiting, vertigo, and tobacco use (20 cigarettes/day). Fabry disease was diagnosed in 2005 when she experienced proteinuria, preeclampsia, and hypertension (201/130 mm Hg) during pregnancy (delivered 50 cm, 3.4 kg healthy boy; GLA wild type [WT]). Enzyme replacement therapy was initiated in 2009. The patient enrolled in the phase 3 ATTRACT trial (ClinicalTrials.gov; NCT01218659) and started migalastat in May 2012 while taking hormonal contraceptives. Two years after initiating migalastat, the patient had proteinuria (2166 mg/24 h) without hypertension (131/68 mm Hg), which persisted (788 mg/24 h a month later). Kidney biopsy results were consistent with existing Fabry disease. A serum pregnancy test and ultrasound confirmed pregnancy (18 weeks' gestation). Migalastat and hormonal contraceptives were stopped; the patient continued to smoke. Fetal MRI was normal at ~29 weeks' gestation. In October 2014, at 37+ weeks' gestation, the patient delivered a 45-cm, 2.29-kg healthy girl (GLA WT). Excepting low birth weight, which may be related to the patient's smoking, pregnancy outcome was normal despite exposure to migalastat for 18 weeks. Migalastat therapy during pregnancy is not advised.

Migalastat improves diarrhea in patients with Fabry disease: clinical-biomarker correlations from the phase 3 FACETS trial.

BACKGROUND: Fabry disease is frequently characterized by gastrointestinal symptoms, including diarrhea. Migalastat is an orally-administered small molecule approved to treat the symptoms of Fabry disease in patients with amenable mutations. METHODS: We evaluated minimal clinically important differences (MCID) in diarrhea based on the corresponding domain of the patient-reported Gastrointestinal Symptom Rating Scale (GSRS) in patients with Fabry disease and amenable mutations (N = 50) treated with migalastat 150 mg every other day or placebo during the phase 3 FACETS trial (NCT00925301). RESULTS: After 6 months, significantly more patients receiving migalastat versus placebo experienced improvement in diarrhea based on a MCID of 0.33 (43% vs 11%; p = .02), including the subset with baseline diarrhea (71% vs 20%; p = .02). A decline in kidney peritubular capillary globotriaosylceramide inclusions correlated with diarrhea improvement; patients with a reduction > 0.1 were 5.6 times more likely to have an improvement in diarrhea than those without (p = .031). CONCLUSIONS: Migalastat was associated with a clinically meaningful improvement in diarrhea in patients with Fabry disease and amenable mutations. Reductions in kidney globotriaosylceramide may be a useful surrogate endpoint to predict clinical benefit with migalastat in patients with Fabry disease. TRIAL REGISTRATION: NCT00925301 ; June 19, 2009.

Low frequency of Fabry disease in patients with common heart disease.

PURPOSE: To test the hypothesis that undiagnosed patients with Fabry disease exist among patients affected by common heart disease. METHODS: Globotriaosylceramide in random whole urine using tandem mass spectroscopy, α-galactosidase A activity in dried blood spots, and next-generation sequencing of pooled or individual genomic DNA samples supplemented by Sanger sequencing. RESULTS: We tested 2,256 consecutive patients: 852 women (median age 65 years (19-95)) and 1,404 men (median age 65 years (21-92)). The primary diagnoses were coronary artery disease (n = 994), arrhythmia (n = 607), cardiomyopathy (n = 138), and valvular disease (n = 568). Urinary globotriaosylceramide was elevated in 15% of patients and 15 males had low α-galactosidase A activity. GLA variants found included R118C (n = 2), D83N, and D313Y (n = 7); IVS6-22 C>T, IVS4-16 A>G, IVS2+990C>A, 5'UTR-10 C>T (n = 4), IVS1-581 C>T, IVS1-1238 G>A, 5'UTR-30 G>A, IVS2+590C>T, IVS0-12 G>A, IVS4+68A>G, IVS0-10 C>T, IVS2-81-77delCAGCC, IVS2-77delC. Although the pathogenicity of several of these missense mutations and complex intronic haplotypes has been controversial, none of the patients screened in this study were diagnosed definitively with Fabry disease. CONCLUSION: This population of patients with common heart disease did not contain a substantial number of patients with undiagnosed Fabry disease. GLA gene sequencing is superior to urinary globotriaosylceramide or α-galactosidase A activity in the screening for Fabry disease.

Reduction of podocyte globotriaosylceramide content in adult male patients with Fabry disease with amenable GLA mutations following 6 months of migalastat treatment.

OBJECTIVE: Deficiency of α-galactosidase A (αGal-A) in Fabry disease leads to the accumulation mainly of globotriaosylceramide (GL3) in multiple renal cell types. Glomerular podocytes are relatively resistant to clearance of GL3 inclusions by enzyme replacement therapy (ERT). Migalastat, an orally bioavailable small molecule capable of chaperoning misfolded αGal-A to lysosomes, is approved in the European Union for the long-term treatment of patients with Fabry disease and amenable GLA (α-galactosidase A enzyme) mutations. We aimed to examine if migalastat reduces GL3 content of podocytes in Fabry disease. METHODS AND ANALYSIS: We compared paired renal biopsies of eight adult men with amenable Fabry disease mutations at baseline and after 6 months of treatment with 150 mg migalastat every other day using quantitative unbiased electron microscopic morphometric methods. RESULTS: Migalastat treatment led to a reduction in mean total GL3 inclusion volume per podocyte in renal biopsies from baseline to 6 months. This reduction correlated precisely with reduced mean podocyte volume. There was also a direct relationship between reduction in podocyte foot process width and the reduction in mean total podocyte GL3 content following 6 months of migalastat treatment, suggestive of reduced podocyte injury. CONCLUSION: Migalastat treatment of 6 months duration in eight male patients with Fabry disease demonstrated effective GL3 clearance from the podocyte, an important and relatively ERT-resistant glomerular cell.

Duvoglustat HCl Increases Systemic and Tissue Exposure of Active Acid α-Glucosidase in Pompe Patients Co-administered with Alglucosidase α.

Duvoglustat HCl (AT2220, 1-deoxynojirimycin) is an investigational pharmacological chaperone for the treatment of acid α-glucosidase (GAA) deficiency, which leads to the lysosomal storage disorder Pompe disease, which is characterized by progressive accumulation of lysosomal glycogen primarily in heart and skeletal muscles. The current standard of care is enzyme replacement therapy with recombinant human GAA (alglucosidase alfa [AA], Genzyme). Based on preclinical data, oral co-administration of duvoglustat HCl with AA increases exposure of active levels in plasma and skeletal muscles, leading to greater substrate reduction in muscle. This phase 2a study consisted of an open-label, fixed-treatment sequence that evaluated the effect of single oral doses of 50 mg, 100 mg, 250 mg, or 600 mg duvoglustat HCl on the pharmacokinetics and tissue levels of intravenously infused AA (20 mg/kg) in Pompe patients. AA alone resulted in increases in total GAA activity and protein in plasma compared to baseline. Following co-administration with duvoglustat HCl, total GAA activity and protein in plasma were further increased 1.2- to 2.8-fold compared to AA alone in all 25 Pompe patients; importantly, muscle GAA activity was increased for all co-administration treatments from day 3 biopsy specimens. No duvoglustat-related adverse events or drug-related tolerability issues were identified.

Oral pharmacological chaperone migalastat compared with enzyme replacement therapy in Fabry disease: 18-month results from the randomised phase III ATTRACT study.

BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder caused by GLA mutations, resulting in α-galactosidase (α-Gal) deficiency and accumulation of lysosomal substrates. Migalastat, an oral pharmacological chaperone being developed as an alternative to intravenous enzyme replacement therapy (ERT), stabilises specific mutant (amenable) forms of α-Gal to facilitate normal lysosomal trafficking. METHODS: The main objective of the 18-month, randomised, active-controlled ATTRACT study was to assess the effects of migalastat on renal function in patients with Fabry disease previously treated with ERT. Effects on heart, disease substrate, patient-reported outcomes (PROs) and safety were also assessed. RESULTS: Fifty-seven adults (56% female) receiving ERT (88% had multiorgan disease) were randomised (1.5:1), based on a preliminary cell-based assay of responsiveness to migalastat, to receive 18 months open-label migalastat or remain on ERT. Four patients had non-amenable mutant forms of α-Gal based on the validated cell-based assay conducted after treatment initiation and were excluded from primary efficacy analyses only. Migalastat and ERT had similar effects on renal function. Left ventricular mass index decreased significantly with migalastat treatment (-6.6 g/m2 (-11.0 to -2.2)); there was no significant change with ERT. Predefined renal, cardiac or cerebrovascular events occurred in 29% and 44% of patients in the migalastat and ERT groups, respectively. Plasma globotriaosylsphingosine remained low and stable following the switch from ERT to migalastat. PROs were comparable between groups. Migalastat was generally safe and well tolerated. CONCLUSIONS: Migalastat offers promise as a first-in-class oral monotherapy alternative treatment to intravenous ERT for patients with Fabry disease and amenable mutations. TRIAL REGISTRATION NUMBER: NCT00925301; Pre-results.

The validation of pharmacogenetics for the identification of Fabry patients to be treated with migalastat.

PURPOSE: Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A gene. Migalastat, a pharmacological chaperone, binds to specific mutant forms of α-galactosidase A to restore lysosomal activity. METHODS: A pharmacogenetic assay was used to identify the α-galactosidase A mutant forms amenable to migalastat. Six hundred Fabry disease-causing mutations were expressed in HEK-293 (HEK) cells; increases in α-galactosidase A activity were measured by a good laboratory practice (GLP)-validated assay (GLP HEK/Migalastat Amenability Assay). The predictive value of the assay was assessed based on pharmacodynamic responses to migalastat in phase II and III clinical studies. RESULTS: Comparison of the GLP HEK assay results in in vivo white blood cell α-galactosidase A responses to migalastat in male patients showed high sensitivity, specificity, and positive and negative predictive values (≥0.875). GLP HEK assay results were also predictive of decreases in kidney globotriaosylceramide in males and plasma globotriaosylsphingosine in males and females. The clinical study subset of amenable mutations (n = 51) was representative of all 268 amenable mutations identified by the GLP HEK assay. CONCLUSION: The GLP HEK assay is a clinically validated method of identifying male and female Fabry patients for treatment with migalastat.Genet Med 19 4, 430-438.

Treatment of Fabry's Disease with the Pharmacologic Chaperone Migalastat.

BACKGROUND: Fabry's disease, an X-linked disorder of lysosomal α-galactosidase deficiency, leads to substrate accumulation in multiple organs. Migalastat, an oral pharmacologic chaperone, stabilizes specific mutant forms of α-galactosidase, increasing enzyme trafficking to lysosomes. METHODS: The initial assay of mutant α-galactosidase forms that we used to categorize 67 patients with Fabry's disease for randomization to 6 months of double-blind migalastat or placebo (stage 1), followed by open-label migalastat from 6 to 12 months (stage 2) plus an additional year, had certain limitations. Before unblinding, a new, validated assay showed that 50 of the 67 participants had mutant α-galactosidase forms suitable for targeting by migalastat. The primary end point was the percentage of patients who had a response (≥50% reduction in the number of globotriaosylceramide inclusions per kidney interstitial capillary) at 6 months. We assessed safety along with disease substrates and renal, cardiovascular, and patient-reported outcomes. RESULTS: The primary end-point analysis, involving patients with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy, did not show a significant treatment effect: 13 of 32 patients (41%) who received migalastat and 9 of 32 patients (28%) who received placebo had a response at 6 months (P=0.30). Among patients with suitable mutant α-galactosidase who received migalastat for up to 24 months, the annualized changes from baseline in the estimated glomerular filtration rate (GFR) and measured GFR were -0.30±0.66 and -1.51±1.33 ml per minute per 1.73 m(2) of body-surface area, respectively. The left-ventricular-mass index decreased significantly from baseline (-7.7 g per square meter; 95% confidence interval [CI], -15.4 to -0.01), particularly when left ventricular hypertrophy was present (-18.6 g per square meter; 95% CI, -38.2 to 1.0). The severity of diarrhea, reflux, and indigestion decreased. CONCLUSIONS: Among all randomly assigned patients (with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy), the percentage of patients who had a response at 6 months did not differ significantly between the migalastat group and the placebo group. (Funded by Amicus Therapeutics; ClinicalTrials.gov numbers, NCT00925301 [study AT1001-011] and NCT01458119 [study AT1001-041].).

Oral Migalastat HCl Leads to Greater Systemic Exposure and Tissue Levels of Active α-Galactosidase A in Fabry Patients when Co-Administered with Infused Agalsidase.

UNLABELLED: Migalastat HCl (AT1001, 1-Deoxygalactonojirimycin) is an investigational pharmacological chaperone for the treatment of α-galactosidase A (α-Gal A) deficiency, which leads to Fabry disease, an X-linked, lysosomal storage disorder. The currently approved, biologics-based therapy for Fabry disease is enzyme replacement therapy (ERT) with either agalsidase alfa (Replagal) or agalsidase beta (Fabrazyme). Based on preclinical data, migalastat HCl in combination with agalsidase is expected to result in the pharmacokinetic (PK) enhancement of agalsidase in plasma by increasing the systemic exposure of active agalsidase, thereby leading to increased cellular levels in disease-relevant tissues. This Phase 2a study design consisted of an open-label, fixed-treatment sequence that evaluated the effects of single oral doses of 150 mg or 450 mg migalastat HCl on the PK and tissue levels of intravenously infused agalsidase (0.2, 0.5, or 1.0 mg/kg) in male Fabry patients. As expected, intravenous administration of agalsidase alone resulted in increased α-Gal A activity in plasma, skin, and peripheral blood mononuclear cells (PBMCs) compared to baseline. Following co-administration of migalastat HCl and agalsidase, α-Gal A activity in plasma was further significantly increased 1.2- to 5.1-fold compared to agalsidase administration alone, in 22 of 23 patients (95.6%). Importantly, similar increases in skin and PBMC α-Gal A activity were seen following co-administration of migalastat HCl and agalsidase. The effects were not related to the administered migalastat HCl dose, as the 150 mg dose of migalastat HCl increased α-Gal A activity to the same extent as the 450 mg dose. Conversely, agalsidase had no effect on the plasma PK of migalastat. No migalastat HCl-related adverse events or drug-related tolerability issues were identified. TRIAL REGISTRATION: ClinicalTrials.gov NCT01196871.

Ataluren treatment of patients with nonsense mutation dystrophinopathy.

INTRODUCTION: Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of cases. Ataluren was developed to enable ribosomal readthrough of premature stop codons in nonsense mutation (nm) genetic disorders. METHODS: Randomized, double-blind, placebo-controlled study; males ≥ 5 years with nm-dystrophinopathy received study drug orally 3 times daily, ataluren 10, 10, 20 mg/kg (N=57); ataluren 20, 20, 40 mg/kg (N=60); or placebo (N=57) for 48 weeks. The primary endpoint was change in 6-Minute Walk Distance (6MWD) at Week 48. RESULTS: Ataluren was generally well tolerated. The primary endpoint favored ataluren 10, 10, 20 mg/kg versus placebo; the week 48 6MWD Δ=31.3 meters, post hoc P=0.056. Secondary endpoints (timed function tests) showed meaningful differences between ataluren 10, 10, 20 mg/kg, and placebo. CONCLUSIONS: As the first investigational new drug targeting the underlying cause of nm-dystrophinopathy, ataluren offers promise as a treatment for this orphan genetic disorder with high unmet medical need.

Ataluren for the treatment of nonsense-mutation cystic fibrosis: a randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND: Ataluren was developed to restore functional protein production in genetic disorders caused by nonsense mutations, which are the cause of cystic fibrosis in 10% of patients. This trial was designed to assess the efficacy and safety of ataluren in patients with nonsense-mutation cystic fibrosis. METHODS: This randomised, double-blind, placebo-controlled, phase 3 study enrolled patients from 36 sites in 11 countries in North America and Europe. Eligible patients with nonsense-mutation cystic fibrosis (aged ≥ 6 years; abnormal nasal potential difference; sweat chloride >40 mmol/L; forced expiratory volume in 1 s [FEV1] ≥ 40% and ≤ 90%) were randomly assigned by interactive response technology to receive oral ataluren (10 mg/kg in morning, 10 mg/kg midday, and 20 mg/kg in evening) or matching placebo for 48 weeks. Randomisation used a block size of four, stratified by age, chronic inhaled antibiotic use, and percent-predicted FEV1. The primary endpoint was relative change in percent-predicted FEV1 from baseline to week 48, analysed in all patients with a post-baseline spirometry measurement. This study is registered with ClinicalTrials.gov, number NCT00803205. FINDINGS: Between Sept 8, 2009, and Nov 30, 2010, 238 patients were randomly assigned, of whom 116 in each treatment group had a valid post-baseline spirometry measurement. Relative change from baseline in percent-predicted FEV1 did not differ significantly between ataluren and placebo at week 48 (-2.5% vs -5.5%; difference 3.0% [95% CI -0.8 to 6.3]; p=0.12). The number of pulmonary exacerbations did not differ significantly between treatment groups (rate ratio 0.77 [95% CI 0.57-1.05]; p=0.0992). However, post-hoc analysis of the subgroup of patients not using chronic inhaled tobramycin showed a 5.7% difference (95% CI 1.5-10.1) in relative change from baseline in percent-predicted FEV1 between the ataluren and placebo groups at week 48 (-0.7% [-4.0 to 2.1] vs -6.4% [-9.8 to -3.7]; nominal p=0.0082), and fewer pulmonary exacerbations in the ataluern group (1.42 events [0.9-1.9] vs 2.18 events [1.6-2.7]; rate ratio 0.60 [0.42-0.86]; nominal p=0.0061). Safety profiles were generally similar for ataluren and placebo, except for the occurrence of increased creatinine concentrations (ie, acute kidney injury), which occurred in 18 (15%) of 118 patients in the ataluren group compared with one (<1%) of 120 patients in the placebo group. No life-threatening adverse events or deaths were reported in either group. INTERPRETATION: Although ataluren did not improve lung function in the overall population of nonsense-mutation cystic fibrosis patients who received this treatment, it might be beneficial for patients not taking chronic inhaled tobramycin. FUNDING: PTC Therapeutics, Cystic Fibrosis Foundation, US Food and Drug Administration's Office of Orphan Products Development, and the National Institutes of Health.

Phase 2a study of ataluren-mediated dystrophin production in patients with nonsense mutation Duchenne muscular dystrophy.

BACKGROUND: Approximately 13% of boys with Duchenne muscular dystrophy (DMD) have a nonsense mutation in the dystrophin gene, resulting in a premature stop codon in the corresponding mRNA and failure to generate a functional protein. Ataluren (PTC124) enables ribosomal readthrough of premature stop codons, leading to production of full-length, functional proteins. METHODS: This Phase 2a open-label, sequential dose-ranging trial recruited 38 boys with nonsense mutation DMD. The first cohort (n = 6) received ataluren three times per day at morning, midday, and evening doses of 4, 4, and 8 mg/kg; the second cohort (n = 20) was dosed at 10, 10, 20 mg/kg; and the third cohort (n = 12) was dosed at 20, 20, 40 mg/kg. Treatment duration was 28 days. Change in full-length dystrophin expression, as assessed by immunostaining in pre- and post-treatment muscle biopsy specimens, was the primary endpoint. FINDINGS: Twenty three of 38 (61%) subjects demonstrated increases in post-treatment dystrophin expression in a quantitative analysis assessing the ratio of dystrophin/spectrin. A qualitative analysis also showed positive changes in dystrophin expression. Expression was not associated with nonsense mutation type or exon location. Ataluren trough plasma concentrations active in the mdx mouse model were consistently achieved at the mid- and high- dose levels in participants. Ataluren was generally well tolerated. INTERPRETATION: Ataluren showed activity and safety in this short-term study, supporting evaluation of ataluren 10, 10, 20 mg/kg and 20, 20, 40 mg/kg in a Phase 2b, double-blind, long-term study in nonsense mutation DMD. TRIAL REGISTRATION: ClinicalTrials.gov NCT00264888.