Lysosomal storage disorders: Clinical and therapeutic aspects.

The lysosomal storage disorders are hereditary metabolic disorders characterized by autosomal recessive inheritance, mainly caused by deficiency of an enzyme responsible for the intra-lysosomal breakdown of various substrates and products of cellular metabolism. This chapter examines the underlying defects, clinical manifestations, and provides context for the expected clinical outcome of various available therapy options employing enzyme replacement therapy, hematopoietic stem cell transplantation, substrate reduction, and enzyme enhancement therapies.

Abnormal N-glycan fucosylation, galactosylation, and sialylation of IgG in adults with classical galactosemia, influence of dietary galactose intake.

BACKGROUND: Classical galactosemia (CG) (OMIM #230400) is a rare disorder of carbohydrate metabolism, due to deficiency of galactose-1-phosphate uridyltransferase (EC 2.7.7.12). The pathophysiology of the long-term complications, mainly cognitive, neurological, and female infertility remains poorly understood. OBJECTIVES: This study investigated (a) the association between specific IgG N-glycosylation biomarkers (glycan peaks and grouped traits) and CG patients (n = 95) identified from the GalNet Network, using hydrophilic interaction ultraperformance liquid chromatography and (b) a further analysis of a GALT c.563A-G/p.Gln188Arg homozygous cohort (n = 49) with correlation with glycan features with patient Full Scale Intelligence Quotient (FSIQ), and (c) with galactose intake. RESULTS: A very significant decrease in galactosylation and sialylation and an increase in core fucosylation was noted in CG patients vs controls (P < .005). Bisected glycans were decreased in the severe GALT c.563A-G/p.Gln188Arg homozygous cohort (n = 49) (P < .05). Logistic regression models incorporating IgG glycan traits distinguished CG patients from controls. Incremental dietary galactose intake correlated positively with FSIQ for the p.Gln188Arg homozygous CG cohort (P < .005) for a dietary galactose intake of 500 to 1000 mg/d. Significant improvements in profiles with increased galactose intake were noted for monosialylated, monogalactosylated, and monoantennary glycans. CONCLUSION: These results suggest that N-glycosylation abnormalities persist in CG patients on dietary galactose restriction which may be modifiable to a degree by dietary galactose intake.

Lysosomal Acid Lipase Deficiency: Therapeutic Options.

Lysosomal acid lipase (LAL) deficiency is a metabolic (storage) disorder, encompassing a severe (Wolman disease) and attenuated (Cholesterol ester storage disease) subtype; both inherited as autosomal recessive traits. Cardinal clinical features include the combination of hepatic dysfunction and dyslipidemia, as a consequence of cholesteryl esters and triglyceride accumulation, predominately in the liver and vascular and reticuloendothelial system. Significant morbidity can arise, due to liver failure and/or atherosclerosis; in part related to the severity of the underlying gene defect and corresponding enzyme deficiency. Diagnosis is based on demonstration of decreased LAL enzyme activity, complemented by analysis of the cognate gene defects. Therapeutic options include dietary manipulation and the use of lipid-lowering drugs. Sebelipase alfa, a recombinant enzyme replacement therapy, has garnered regulatory approval, following demonstration of improvements in disease-relevant markers and clinical benefit in clinical trials, which included increased survival in the most severe cases.

Long-term comparative effectiveness of pegvaliase versus standard of care comparators in adults with phenylketonuria.

Phenylketonuria (PKU) is caused by phenylalanine hydroxylase (PAH) deficiency, resulting in high blood and brain Phenylalanine (Phe) concentrations that can lead to impaired brain development and function. Standard treatment involves a Phe-restricted diet alone or in conjunction with sapropterin dihydrochloride in responsive patients. The Food and Drug Administration approved pegvaliase enzyme substitution therapy for adults with blood Phe >600 µmol/L in the US. Recently, the European Commission also approved pegvaliase for treatment of PKU patients aged 16 years or older with blood Phe >600 µmol/L. The analyses presented below were conducted to provide comparative evidence on long-term treatment effectiveness of pegvaliase versus standard of care in adults with PKU. Adult patients (≥18 years) with baseline blood Phe >600 µmol/L who had enrolled in the pegvaliase phase 2 and phase 3 clinical trials were propensity score-matched to historical cohorts of patients treated with "sapropterin + diet" or with "diet alone". These cohorts were derived from the PKU Demographics, Outcome and Safety (PKUDOS) registry and compared for clinical outcomes including blood Phe concentration and natural intact protein intake after 1 and 2 years. Propensity scores were estimated using logistic regression with probability of treatment as outcome (i.e. pegvaliase, "sapropterin + diet", or "diet alone") and patient demographic and disease severity covariates as predictors. An additional analysis in adult PKU patients with baseline blood Phe ≤600 µmol/L comparing non-matched patient groups "sapropterin + diet" to "diet alone" using PKUDOS registry data only was also conducted. The analyses in patients with baseline blood Phe >600 µmol comparing pegvaliase with "sapropterin + diet" (N = 64 matched pairs) showed lower mean blood Phe concentrations after 1 and 2 years with pegvaliase (505 and 427 µmol/L) versus "sapropterin + diet" (807 and 891 µmol/L); mean natural intact protein intake after 1 and 2 years was 49 and 57 g/day respectively with pegvaliase versus 23 and 28 g/day with "sapropterin + diet". The analysis comparing pegvaliase with "diet alone" (N = 120 matched pairs) showed lower mean blood Phe at 1 and 2 years with pegvaliase (473 and 302 µmol/L) versus "diet alone" (1022 and 965 µmol/L); mean natural intact protein intake after 1 and 2 years was 47 and 57 g/day with pegvaliase and 27 and 22 g/day with "diet alone". Considerably more patients achieved blood Phe ≤600, ≤360, and ≤120 µmol/L and reductions from baseline of ≥20%, ≥30%, and ≥50% in blood Phe after 1 and 2 years of pegvaliase versus standard treatments. The analysis in patients with baseline blood Phe ≤600 µmol/L showed lower blood Phe after 1 and 2 years with "sapropterin + diet" (240 and 324 µmol/L) versus "diet alone" (580 and 549 µmol/L) and greater percentages of patients achieving blood Phe targets ≤600, ≤360, and ≤120 µmol/L and reductions from baseline of ≥20%, ≥30%, and ≥50% in blood Phe. These results support pegvaliase as the more effective treatment option to lower Phe levels in adults with PKU who have difficulty keeping blood Phe ≤600 µmol/L with "diet alone". For patients with blood Phe ≤600 µmol/L, adding sapropterin to dietary management is an appropriate treatment option, for those responsive to the treatment.

Metallosis mimicking a metabolic disorder: a case report.

Metalic prosthesis or occupational exposure are potential sources of systemic cobalt and chromium ion toxicity. The resultant multisystemic clinical presentation can lead to unnecessary investigations before a final etiologic diagnosis is made; with an average delay of a year or more commonly noted. A 58-year old man presented with cardiomyopathy, pericardial effusion, polycytaemia, polyneuropathy, visual impairment, sudden hearing loss and hypothyroidism over a 2-year period post a metal-on-polyethylene hip replacement surgery. Biochemistry test results showed serum lactate of 3.8 mmol/L (0.5-2.2 mmol/L). Urine organic acid screen showed mild increases in excretion of tricarboxylic acid cycle intermediates and 2-ethylhydracryllate; suggestive of primary or secondary mitochondrial dysfunction. There were also slight increases in excretion of 4-hydroxyphenyllactate and 4-hydroxyphenylpyruvate suggestive of liver dysfunction. Acylcarnitine profile showed slight increase in hydroxybutyrylcarnitine and tetradeceneoylcarnitine that may reflect ketosis. In view of his clinical presentation and abnormal metabolic investigations, the initial working diagnosis was mitochondrial disease. Subsequently, patient presented with hip pain, and radiologic and imaging studies revealed high density collections lateral to the right proximal part of the femur, and medial to the right ilium with signal changes suggestive of metallic content. This prompted toxicology screen which revealed elevated plasma cobalt concentration (903.32 µg/L; reference range: 0.1-0.4) and chromium (71.32 µg/L; <0.5). Six months post right hip prosthesis removal the concentrations have declined and was 61.72 µg/L and chromium 23.97 µg/L. Patient felt some improvement symptomatically, without evident deterioration in his vision or hearing. This case emphasises careful consideration of past medical history, in patients presenting with multisystemic disease suggestive of mitochondrial dysfunction, and potential causality related to exposure to toxic agents. In retrospect, the absence of a family history could be viewed as a pertinent negative finding. Not uncommonly, specialist focus on their favored system and may not search for a unifying diagnosis. It is likely further delays in diagnosis would have occurred had the patient not developed hip pains, and ultimately referred to the orthopedic surgeons more familiar with similar cases.

Neurocognitive assessments and long-term outcome in an adult with 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency.

BACKGROUND: 2-Methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency (MHBDD) is a rare X-linked disorder associated with the accumulation of 2-methyl-3-hydroxybutyric acid in body fluids as a consequence of a disruption in isoleucine metabolism. The clinical presentation is heterogeneous, including a neurodegenerative course with retinopathy and cardiomyopathy leading to death in early childhood and a slowly progressive disease associated with learning disability and survival into adulthood. The condition is often diagnosed in childhood. RESULTS: This paper outlines the long-term neurocognitive outcomes in a 38-year old man with MHBDD. Several psychometric tests were used to assess his cognitive ability and adaptive functioning in childhood during an acute illness and in adulthood when the patient showed deterioration in the ability to walk or speak. CONCLUSIONS: There is an increasing demand for an accurate and objective measure of cognitive functioning that can be used to follow the natural progression of MHBDD. Psychological assessment may enable the identification of organic problems. The application and interpretation of psychometric tests used in children may vary from those used in adults.

The benefits of a Neurogenetics clinic in an adult Academic Teaching Hospital.

Genetics is the backbone of Neurology, where a number of disorders have a genetic aetiology and are complex, requiring a dedicated Neurogenetics clinic. Genetics in the Republic of Ireland is under-resourced, with the lowest number of consultants per million of population in Europe. In November 2014, we established the monthly adult Neurogenetics clinic in Ireland, staffed by 2 consultants and 2 registrars from each speciality. We see patients with complex rare neurological conditions that may potentially have an underlying genetic basis, in the presence or absence of a family history. We performed a retrospective cohort analysis, reviewing symptoms and work-up data. Twenty-seven patients attended a pilot clinic over 12 months. Conditions encountered included Parkin-related PD, leucodystrophy, ataxia, fronto-temporal lobar degeneration, spinocerebellar ataxia type 6 (SCA6) and ataxia-telangiectasia. Identification of pathogenic mutations directed screening, treatment and facilitated onward genetic counselling (n = 10, 33%). A number of novel mutations were identified in MAPT gene ("missing tau mutation" McCarthy et al., Brain, 2015), SLCA1 gene and GRN (progranulin). Phenotypic features not previously reported were seen; e.g. writer's cramp in SCA6; paroxysmal myoclonus in the glucose transporter protein type 1 (GLUT1) deficiency. Breast cancer screening for ATM mutations carriers and referral to international experts in two undiagnosed patients were arranged. The establishment of a Neurogenetics clinic has addressed a gap in service and allowed identification of rare and atypical diagnoses.

Chitinase-3-like Protein 1: A Progranulin Downstream Molecule and Potential Biomarker for Gaucher Disease.

We recently reported that progranulin (PGRN) is a novel regulator of glucocerebrosidase and its deficiency associates with Gaucher Diseases (GD) (Jian et al., 2016a; Jian et al., 2018). To isolate the relevant downstream molecules, we performed a whole genome microarray and mass spectrometry analysis, which led to the isolation of Chitinase-3-like-1 (CHI3L1) as one of the up-regulated genes in PGRN null mice. Elevated levels of CHI3L1 were confirmed by immunoblotting and immunohistochemistry. In contrast, treatment with recombinant Pcgin, a derivative of PGRN, as well as imigluerase, significantly reduced the expressions of CHI3L1 in both PGRN null GD model and the fibroblasts from GD patients. Serum levels of CHIT1, a clinical biomarker for GD, were significantly higher in GD patients than healthy controls (51.16±2.824ng/ml vs 35.07±2.099ng/ml, p<0.001). Similar to CHIT1, serum CHI3L1 was also significantly increased in GD patients compared with healthy controls (1736±152.1pg/ml vs 684.7±68.20pg/ml, p<0.001). Whereas the PGRN level is significantly reduced in GD patients as compared to the healthy control (91.56±3.986ng/ml vs 150.6±4.501, p<0.001). Collectively, these results indicate that CHI3L1 may be a previously unrecognized biomarker for diagnosing GD and for evaluating the therapeutic effects of new GD drug(s).

Taliglucerase alfa: safety and efficacy across 6 clinical studies in adults and children with Gaucher disease.

Taliglucerase alfa is an enzyme replacement therapy (ERT) approved for treatment of adult and paediatric patients with Type 1 Gaucher disease (GD) in several countries and the first plant cell-expressed recombinant therapeutic protein approved by the US Food and Drug Administration for humans. Here, we review the findings across six key taliglucerase alfa clinical studies. A total of 33 treatment-naïve adult patients were randomized to taliglucerase alfa 30 U/kg or 60 U/kg in a 9-month, multicentre, randomized, double-blind, parallel-group, dose-comparison pivotal study, after which eligible patients continued into two consecutive extension studies; 17 treatment-naïve adult patients completed 5 total years of treatment with taliglucerase alfa. In the only ERT study focused on exclusively paediatric patients with GD, 11 treatment-naïve children were randomized to taliglucerase alfa 30 U/kg or 60 U/kg in a 12-month, multicentre, double-blind study; nine completed 3 total years of treatment in a dedicated paediatric extension study. The effect of switching patients from imiglucerase to taliglucerase alfa was also investigated in a separate 9-month study that included 26 adults and five children; 10 adults completed a total of 3 years and two children completed a total of 2.75 years of taliglucerase alfa treatment in the extension studies. All studies evaluated safety and spleen volume, liver volume, platelet count, haemoglobin concentration, and biomarkers as measures of efficacy. Detailed results from baseline through the end of these studies are presented. Taliglucerase alfa was well tolerated, and adverse events were generally mild/moderate in severity and transient. Treatment with taliglucerase alfa resulted in improvements (treatment-naïve patients) or stability (patients switched from imiglucerase) in visceral, haematologic, and biomarker parameters. Together, this comprehensive data set supports the treatment of adult and paediatric patients with GD who are naïve to ERT or who have previously been treated with imiglucerase.

Two Uneventful Pregnancies in a Woman with Glutaric Aciduria Type 1.

Glutaric aciduria type 1 (GA1) is an autosomal recessive rare disorder caused by mutations in the GCDH gene resulting in deficiency of glutaryl-CoA dehydrogenase, leading to accumulation of the amino acids lysine, hydroxylysine and tryptophan and other metabolites. The phenotypic spectrum of disease is broad. Stress caused by infection and fever and possibly pregnancy may lead to worsening of the signs and symptoms, often with uncertain recovery.We describe a case of a female patient with GA1 who had two clinically uneventful pregnancies.At the age of 11 she was diagnosed with GA1 by family screening. The cultured skin fibroblast showed reduced glutaryl-CoA dehydrogenase activity (0.16 mg protein per min).The initial diagnostic urine glutaric acid level for this patient was 1,784 µmol/mmol creatinine. Mutation analysis showed compound heterozygosity for the p.(Gly185Arg), c.553G>A in exon 7 and p.(Arg402Trp), c.1204C.T in exon 11 mutations of the GCDH.Her pregnancy at the age of 23 was complicated by pre-eclampsia and required treatment with beta-blockers. Four years later the second pregnancy was uncomplicated. The management plan during the caesarean section included intravenous dextrose and lipid infusions. The patient rapidly recovered from both surgeries.Both babies have had normal development to date. On newborn screening, plasma acylcarnitine showed a transient increase in glutarylcarnitine, and the urine organic acid analysis showed a trace of 3-hydroxyglutarylcarnitine, likely to be of maternal transfer.The multidisciplinary team, consisting of metabolic, dietetic and obstetric care providers, have responsibility to ensure the risk of acute decompensation in pregnant GA1 women is minimal.

Cardiopulmonary Exercise Testing Reflects Improved Exercise Capacity in Response to Treatment in Morquio A Patients: Results of a 52-Week Pilot Study of Two Different Doses of Elosulfase Alfa.

OBJECTIVE: To assess impact of a 52-week elosulfase alfa enzyme replacement therapy (ERT) on exercise capacity in Morquio A patients and analyze cardiorespiratory and metabolic function during exercise to uncover exercise limitations beyond skeletal abnormalities. METHODS: Morquio A patients aged ≥7 years, able to walk >200 m in the 6-minute walk test (6MWT), received elosulfase alfa 2.0 mg/kg/week (N = 15) or 4.0 mg/kg/week (N = 10) for 52 weeks in the randomized, double-blind MOR-008 study ( ClinicalTrials.gov NCT01609062) and its extension. Exercise capacity was assessed by 6MWT, 3-minute stair climb test (3MSCT), and cardiopulmonary exercise test (CPET; N = 15 dosage groups combined). RESULTS: Changes over 52 weeks in 6MWT and 3MSCT were minimal. Baseline CPET results showed impaired weight-adjusted peak oxygen uptake (VO2), partly attributable to inability to increase tidal volume during exercise. CPET measures of exercise function showed significant improvement at 25 and/or 52 weeks in exercise duration, peak workload, O2 pulse, and peak tidal volume (% increases in duration, 16.9 (P = 0.0045) and 9.4 (P = 0.0807); peak workload, 26.5 (P = 0.0026) and 21.2 (P = 0.0132); O2 pulse, 10.7 (P = 0.0187) and 2.3 (P = 0.643); peak tidal volume, 11.7 (P = 0.1117) and 29.1 (P = 0.0142)). In addition, decreased VO2/work ratio was noted (% decrease -7.6 [-11.9, 1.3] and -9.2 [-25.7, 5.1]), indicating performance of work at reduced oxygen cost. CONCLUSIONS: CPET uncovers limitation in exercise capacity in Morquio A related to reduced lung function. ERT improves exercise capacity and efficiency of oxygen utilization, not attributable to changes in cardiac or pulmonary function. Further study of the long-term impact of ERT on exercise capacity and the clinical relevance of the observed changes is warranted.

Lysosomal Storage Disorders and Malignancy.

Lysosomal storage disorders (LSDs) are infrequent to rare conditions caused by mutations that lead to a disruption in the usual sequential degradation of macromolecules or their transit within the cell. Gaucher disease (GD), a lipidosis, is among the most common LSD, with an estimated incidence of 1 in 40,000 among the Caucasian, non-Jewish population. Studies have indicated an increased frequency of polyclonal and monoclonal gammopathy among patients with GD. It has been shown that two major sphingolipids that accumulate in GD, namely, ß-glucosylceramide 22:0 (ßGL1-22) and glucosylsphingosine (LGL1), can be recognized by a distinct subset of CD1d-restricted human and murine type II natural killer T (NKT) cells. Investigations undertaken in an affected mouse model revealed ßGL1-22- and LGL1-specific NKT cells were present and constitutively promoted the expression of a T-follicular helper (TFH) phenotype; injection of these lipids led to downstream induction of germinal center B cells, hypergammaglobulinemia, and the production of antilipid antibodies. Subsequent studies have found clonal immunoglobulin in 33% of sporadic human monoclonal gammopathies is also specific for the lysolipids LGL1 and lysophosphatidylcholine (LPC). Furthermore, substrate reduction ameliorated GD-associated gammopathy in mice. It had been hypothesized that chronic antigenic stimulation by the abnormal lipid storage and associated immune dysregulation may be the underlying mechanism for the increased incidence of monoclonal and polyclonal gammopathies, as well as an increased incidence of multiple myeloma in patients with GD. Current observations support this proposition and illustrate the value of investigations into rare diseases, which as 'experiments of nature' may provide insights into conditions found in the general population that continue to remain incompletely understood.

Exploring the patient journey to diagnosis of Gaucher disease from the perspective of 212 patients with Gaucher disease and 16 Gaucher expert physicians.

Gaucher disease (GD) is a rare hereditary disorder caused by a deficiency of the lysosomal enzyme ß-glucocerebrosidase. Diagnosis is challenging owing to a wide variability in clinical manifestations and severity of symptoms. Many patients may experience marked delays in obtaining a definitive diagnosis. The two surveys reported herein aimed to explore the patient journey to diagnosis of GD from the perspectives of Gaucher expert physicians and patients. Findings from the surveys revealed that many patients experienced diagnostic delays and misdiagnoses, with nearly 1 in 6 patients stating that they were not diagnosed with GD for 7years or more after first consulting a doctor. Physicians and patients both reported multiple referrals to different specialties before a diagnosis of GD was obtained, with primary care, haematology/haematology-oncology and paediatrics the main specialties to which patients first presented. Splenomegaly, thrombocytopenia, anaemia and bone pain were reported as the most common medical problems at first presentation in both surveys. These findings support a clear need for straightforward and easy-to-follow guidance designed to assist non-specialists to identify earlier patients who are at risk of GD.

Home infusion of intravenous velaglucerase alfa: Experience from pooled clinical studies in 104 patients with type 1 Gaucher disease.

The introduction of a home therapy option during clinical trials of velaglucerase alfa in patients with type 1 Gaucher disease marked the first time that home infusions have been permitted during a clinical trial for an investigational drug for Gaucher disease. Home infusions were an available option in 4 open-label velaglucerase alfa clinical studies to eligible patients who received their initial infusions at a clinic. Patients who participated in the home therapy option and received at least 10% of their infusions at home (n=100) received a range of 11.6%-100% of their scheduled infusions at home (median 87.5%), excluding infusions received at the clinic during protocol-mandated visits. The length of time over which individual patients received home therapy ranged from 13days to 4.56years (median 0.57years). During the time that home therapy was available, 2904 of 3572 (81.3%) infusions were administered at home. Ten patients experienced 62 infusion-related adverse events (IRAEs) during 38 home infusions, with malaise, pain, hypertension, fatigue, and headache being reported most frequently. No notable differences were found between the type and severity of IRAEs experienced at home and those experienced at the clinic. Home infusions administered by trained and qualified medical personnel were successfully introduced into the velaglucerase alfa clinical development program, and fewer than 10% of patients experienced IRAEs in the home setting. Local labeling and practice guidelines should be consulted for administration of velaglucerase alfa infusions at home.

Spotlight on taliglucerase alfa in the treatment of pediatric patients with type 1 Gaucher disease.

Gaucher disease (GD) is a heritable storage disorder caused by functional defects of the lysosomal acid ß-glucosidase and the accumulation of glucosylceramide within macrophages, resulting in multiple organ dysfunction. There are three commercially available enzyme replacement therapy (ERT) products for the treatment of GD type 1 (GD1): imiglucerase, velaglucerase alfa, and taliglucerase alfa. Imiglucerase and velaglucerase alfa are produced in different mammalian cell systems; imiglucerase requires postproduction deglycosylation to expose terminal α-mannose residues, which are required for mannose receptor-mediated uptake by target macrophages. These steps are critical to the success of ERT for the treatment of visceral and hematologic manifestations of GD. Taliglucerase alfa is the first US Food and Drug Administration-approved plant-cell-expressed recombinant human protein, using carrot root cell cultures. Furthermore, it does not require postproduction glycosidic modifications. It is indicated for treatment of adults with GD1 in the US, Israel, Australia, Canada, Chile, Brazil, and other countries, and it is additionally approved for the treatment of pediatric patients in the US, Australia, and Canada and for the treatment of hematologic manifestations in pediatric patients with Type 3 GD in Canada and other countries. Our review focuses on the role of taliglucerase alfa in the pediatric population. A literature search through PubMed (from 1995 up till November 2016) of English language articles was performed with the following terms: Gaucher disease, lysosomal storage disease, taliglucerase. Secondary and tertiary references were obtained by reviewing related articles as well as the website www.Clinicaltrials.gov. It has been demonstrated that taliglucerase alfa is efficacious, with a well-established safety profile in pediatric, ERT-naïve patients with symptomatic GD1, as well as for those patients previously treated with imiglucerase.

Impact of Elosulfase Alfa on Pain in Patients with Morquio A Syndrome over 52 Weeks: MOR-008: A Randomized, Double-Blind, Pilot Study

Abstract Patients with mucopolysaccharidosis (MPS), and Morquio A syndrome (MPS IVA) in particular, often report substantial pain burden. MOR-008 was a randomized, double-blind, pilot study assessing the safety and efficacy, including impact on patient-reported pain, of 52 weeks of treatment with elosulfase alfa (at a dose of 2.0 or 4.0 mg/kg/week) in patients with Morquio A syndrome (?7 years old). Assessment of pain at baseline revealed that patients (N = 25) had a mean number of pain locations of 5.7, mean pain intensity score of 4.6 (indicative of medium pain), and a mean number of selected pain descriptors of 7.4 words. Treatment with elosulfase alfa improved subjective pain score (reduced to 3.2), pain locations (reduced by a mean of 1 location), and pain descriptor words (reduced to 4.9 words) over 1 year (52 weeks), suggesting that elosulfase alfa can reduce pain in some patients with Morquio A.

Glucosylsphingosine is a key biomarker of Gaucher disease.

Gaucher disease (GD) involves the accumulation of glucosylceramide (GL1) and its deacylated lysolipid, glucosylsphingosine (lyso-GL1) which is implicated in mediating immune dysregulation and skeletal disease. The aim of our study was to assess plasma Lyso-GL1 as a biomarker of GD and its response to therapy. Plasma lyso-GL1 in 169 patients with GD type 1 (GD1) was measured by LC-MS/MS. Significant predictors of plasma LGL1 were assessed by Pearson's correlation coefficient, Wilcoxon Mann Whitney test and multiple linear regression. Propensity scores were used to match patients on treatment mode: Enzyme Replacement Therapy (ERT) vs. Eliglustat Tartrate SRT (ELI-SRT). Plasma Lyso-GL1 levels in healthy controls averaged 1.5 ng/ml (1.3-1.7; 95% CI). In untreated GD patients, the levels were massively elevated (180.9 ng/ml: 95% CI, 145.4-216.5) and imiglucerase ERT resulted in marked reduction (89 ng/ml: 95% CI, 69.2-129.4) (P < 0.001). Lyso-GL1 correlated with chitotriosidase (r = 0.59 P < 0.001), CCL18 (r = 0.62 P <0.001), hepatomegaly (r = 0.28 P < 0.001), splenomegaly (r = 0.27 P = 0.003), splenectomy (P = 0.01) and treatment mode (P < 0.001). By multiple linear regression, the strongest predictors of lyso-GL1 were age (P < 0.001), splenectomy (P = 0.02), Chitotriosidase (P < 0.001) and CCL18 levels (P = 0.001). After propensity score matching to obtain comparable groups of patients on ERT vs ELI-SRT, lyso-GL1 levels were lower among patients receiving ELI-SRT by 113 ng/ml (95% CI: 136-90.3 ng/ml P < 0.001). Plasma lyso-GL1 is a key biomarker of GD. ERT reduced lyso-GL1 levels. By propensity scoring, ELI-SRT resulted in greater reduction of lyso-GL1 than ERT. Am. J. Hematol. 91:1082-1089, 2016. © 2016 Wiley Periodicals, Inc.

Development of anti-velaglucerase alfa antibodies in clinical trial-treated patients with Gaucher disease.

Anti-drug antibodies may develop with biological therapies, possibly leading to a reduction of treatment efficacy and to allergic and other adverse reactions. Patients with Gaucher disease were tested for anti-drug antibodies every 6 or 12weeks in clinical studies of velaglucerase alfa enzyme replacement therapy, as part of a range of safety endpoints. In 10 studies between April 2004 and March 2015, 289 patients aged 2-84years (median 43years) were assessed for the development of anti-velaglucerase alfa antibodies. Sixty-four patients were treatment-naïve at baseline and 225 patients were switched to velaglucerase alfa from imiglucerase treatment. They received velaglucerase alfa treatment for a median of 36.4weeks (interquartile range 26.4-155.4weeks). Four patients (1.4%) became positive for anti-velaglucerase alfa IgG antibodies, two of whom had antibodies that were neutralizing in vitro, but there were no apparent changes in patients' platelet counts, hemoglobin levels or levels of CCL18 and chitotriosidase, suggestive of clinical deterioration after anti-velaglucerase alfa antibodies were detected, and no infusion-related adverse events were reported. Less than 2% of patients exposed to velaglucerase alfa tested positive for antibodies and there was no apparent correlation between anti-velaglucerase alfa antibodies and adverse events or pharmacodynamic or clinical responses.