Rapid home therapy infusion of velaglucerase alfa in naïve patients with Gaucher disease.

BACKGROUND: Enzyme replacement therapy (ERT) has revolutionised the management of patients with Gaucher disease (GD). In 2018, we published the safety and efficacy of rapid 10-min infusion of velaglucerase alfa in previously treated patients, mostly on low-dose therapy. AIM: To improve quality of life (QoL) for patients needing lifelong bi-weekly infusions by introducing a 10-min infusion instead of 1 h per label in patients naive to ERT and on high-dose therapy. METHODS: Fifteen naive patients were enrolled; all received bi-weekly infusions of 60 units/kgBW velaglucerase alfa; the infusion rate was gradually reduced in the hospital, followed by home infusions. Each infusion was followed for safety. Efficacy parameters were assessed every 3 months. Patient-reported outcome questionnaires were collected at baseline and follow-up. RESULTS: Ten-minute rapid infusions were well tolerated without related severe adverse events (SAEs). Two patients experienced a non-related SAE and another a possibly related AE. In three patients, the infusion rate was increased to 30 or 60 min (two because of suboptimal response and one because of AE). Two patients dropped out because of an unwillingness to attend follow-up visits during the COVID-19 pandemic. All 13 remaining patients reached the 24-month end-point. The platelet counts increased by a median (range) of 68.38% (12.5-300%) and the lyso-Gb1 levels decreased by 62.6% (32.9-89.9%). CONCLUSION: Home therapy with rapid infusion of high-dose velaglucerase alfa was a safe, effective and preferable alternative for patients with GD naïve to treatment. We believe that shortening the infusion time improves the QoL of patients with GD who have a lifelong commitment to intravenous therapy.

Contribution of Glucosylsphingosine (Lyso-Gb1) to Treatment Decisions in Patients with Gaucher Disease.

Glucosylsphingosine (lyso-Gb1), the deacylated form of glucocerebroside, was shown to be the most specific and sensitive biomarker for diagnosing Gaucher disease (GD). The aim of this study is to assess the contribution of lyso-Gb1 at the time of diagnosis for treatment decisions in naïve patients with GD. Newly diagnosed patients from July 2014 to November 2022 were included in this retrospective cohort study. The diagnosis was done by sending a dry blood spot (DBS) sample for GBA1 molecular sequencing and lyso-Gb1 quantification. Treatment decisions were based on symptoms, signs, and routine laboratory tests. We diagnosed 97 patients (41 males), both type 1 (n = 87), and neuronopathic (n = 10). The median (range) age at diagnosis was 22 (1-78), with 36 children. In 65 patients, GD-specific therapy was started with a median (range) lyso-Gb1, 337 (60-1340) ng/mL, significantly higher than in patients who did not go on to treatment, 153.5 (9-442) ng/mL. Using a receiver operating characteristic (ROC) analysis, a cutoff of lyso-Gb1 > 250 ng/mL was associated with treatment with a sensitivity of 71% and specificity of 87.5%. Predictors of treatment were thrombocytopenia, anemia, and elevated lyso-Gb1 (>250 ng/mL). In conclusion, lyso-Gb1 levels contribute to the medical decision related to the initiation of treatment, mainly among mildly affected newly diagnosed patients. For patients with a severe phenotype, as for all patients, the main value of lyso-Gb1 would be to monitor response to therapy. The variable methodology and differences in the units of lyso-Gb1 measurements between laboratories prevent the adaptation of the exact cut-off we found in general practice. However, the concept is that a significant elevation, i.e., a several-fold increase from the diagnostic lyso-Gb1 cutoff, is related to a more severe phenotype and, accordingly, to the decision regarding the initiation of GD-specific therapy.

Gaucher Disease Diagnosis Using Lyso-Gb1 on Dry Blood Spot Samples: Time to Change the Paradigm?

For years, the gold standard for diagnosing Gaucher disease (GD) has been detecting reduced ß-glucocerebrosidase (GCase) activity in peripheral blood cells combined with GBA1 mutation analysis. The use of dried blood spot (DBS) specimens offers many advantages, including easy collection, the need for a small amount of blood, and simpler transportation. However, DBS has limitations for measuring GCase activity. In this paper, we recount our cross-sectional study and publish seven years of experience using DBS samples and levels of the deacylated form of glucocerebroside, glucosylsphingosine (lyso-Gb1), for GD diagnosis. Of 444 screened subjects, 99 (22.3%) were diagnosed with GD at a median (range) age of 21 (1-78) years. Lyso-Gb levels for genetically confirmed GD patients vs. subjects negative to GD diagnosis were 252 (9-1340) ng/mL and 5.4 (1.5-16) ng/mL, respectively. Patients diagnosed with GD1 and mild GBA1 variants had lower median (range) lyso-Gb1, 194 (9-1050), compared to GD1 and severe GBA1 variants, 447 (38-1340) ng/mL, and neuronopathic GD, 325 (116-1270) ng/mL (p = 0.001). Subjects with heterozygous GBA1 variants (carrier) had higher lyso-Gb1 levels, 5.8 (2.5-15.3) ng/mL, compared to wild-type GBA1, 4.9 (1.5-16), ng/mL (p = 0.001). Lyso-Gb1 levels, median (range), were 5 (2.7-10.7) in heterozygous GBA1 carriers with Parkinson's disease (PD), similar to lyso-Gb1 levels in subjects without PD. We call for a paradigm change for the diagnosis of GD based on lyso-Gb1 measurements and confirmatory GBA1 mutation analyses in DBS. Lyso-Gb1 levels could not be used to differentiate between heterozygous GBA1 carriers and wild type.

A Comprehensive Assessment of Qualitative and Quantitative Prodromal Parkinsonian Features in Carriers of Gaucher Disease-Identifying Those at the Greatest Risk.

Carriers of GBA1 gene variants have a significant risk of developing Parkinson's disease (PD). A cohort study of GBA carriers between 40−75 years of age was initiated to study the presence of prodromal PD features. Participants underwent non-invasive tests to assess different domains of PD. Ninety-eight unrelated GBA carriers were enrolled (43 males) at a median age (range) of 51 (40−74) years; 71 carried the N370S variant (c.1226A > G) and 25 had a positive family history of PD. The Montreal Cognitive Assessment (MoCA) was the most frequently abnormal (23.7%, 95% CI 15.7−33.4%), followed by the ultrasound hyperechogenicity (22%, 95% CI 14−32%), Unified Parkinson's Disease Rating Scale part III (UPDRS-III) (17.2%, 95% CI 10.2−26.4%), smell assessment (12.4%, 95% CI 6.6−20.6%) and abnormalities in sleep questionnaires (11%, 95% CI 5.7−19.4%). Significant correlations were found between tests from different domains. To define the risk for PD, we assessed the bottom 10th percentile of each prodromal test, defining this level as "abnormal". Then we calculated the percentage of "abnormal" tests for each subject; the median (range) was 4.55 (0−43.5%). Twenty-two subjects had more than 15% "abnormal" tests. The limitations of the study included ascertainment bias of individuals with GBA-related PD in relatives, some incomplete data due to technical issues, and a lack of well-characterized normal value ranges in some tests. We plan to enroll additional participants and conduct longitudinal follow-up assessments to build a model for identifying individuals at risk for PD and investigate interventions aiming to delay the onset or perhaps to prevent full-blown PD.

Upgrading the evidence for the use of ambroxol in Gaucher disease and GBA related Parkinson: Investigator initiated registry based on real life data.

Ambroxol hydrochloride is an oral mucolytic drug available over-the-counter for many years as cough medicine. In 2009 it was identified as a pharmacological chaperone for mutant glucocerebrosidase, albeit in a several-fold higher dose. Unfortunately, there have been no pharma-driven clinical trials to establish its use. Thus, real-world observational data are needed on the safety and efficacy of ambroxol for patients with Gaucher disease (GD) and GBA-Parkinson disease (GBA-PD). Clinicians treating patients with ambroxol for GD and GBA-PD were approached to collaborate in an investigator-initiated registry. Anonymized data were collected, including demographics, GD type, GD-specific therapy (when applicable), adverse events (AEs), and, when available, efficacy data. We report the data of the first 41 patients (25 females) at a median (range) age 17 (1.5-74) from 13 centers; 11 with GD type 1(four diagnosed with PD), 27 with neuronopathic GD (nGD), and three GBA mutation carriers with PD. The median (range) treatment period and maximum dose of ambroxol were 19 (1-76) months and 435 (75-1485) mg/day, respectively. One patient with type 2 GD died of her disease. No other severe AEs were reported. Twelve patients experienced AE, including minor bowel discomfort, cough, allergic reaction, mild proteinuria, dizziness and disease progression. Clinical benefits were reported in 25 patients, including stable or improved neurological status, increased physical activity, and reduced fatigue. Until the approval of specific therapies for nGD and disease-modification for GBA-PD, these preliminary data may be encouraging to physicians and patients who consider an off-label use of ambroxol.

Impact of Long-Term Enzyme Replacement Therapy on Glucosylsphingosine (Lyso-Gb1) Values in Patients with Type 1 Gaucher Disease: Statistical Models for Comparing Three Enzymatic Formulations.

For three decades, enzyme replacement therapy (ERT), and more recently, substrate reduction therapy, have been the standard-of-care for type I Gaucher disease (GD1). Since 2012, three different ERTs have been available. No clinical trial or academic study has ever compared these ERTs beyond one year. Herein we compare the impact of the ERTs on repeated measurements of glucosylsphingosine (lyso-Gb1; the most sensitive and GD-specific biomarker). A total of 135 adult patients (77 (57%) female) with GD1, followed from July 2014 to March 2020 and treated with a single ERT (imiglucerase (n = 41, 30.4%), taliglucerase alfa (n = 21, 15.6%) and velaglucerase alfa (n = 73, 54.1%)), were included. Disease severity was defined by genotypes (mild: N370S (c.1226A>G) homozygous and N370S/R496H (c.1604G) compound heterozygous; severe: all other genotypes) and by the severity score index (SSI; mild: <7; severe: ≥7). Lyso-Gb1 testing was performed at Centogene™ on dry blood spot samples collected during routine visits. Patients treated with imiglucerase had higher lyso-Gb1 levels at different time points. A huge variation in lyso-Gb1 levels was noticeable both inter-individually and intra-individually for all three ERTs. A steeper and faster decrease of lyso-Gb1 levels was shown in velaglucerase alfa. Nevertheless, the differences between medications were not very large, and bigger numbers and more pretreatment data are required for more powerful conclusions.

Response of ophthalmologists in Israel to the novel coronavirus (2019-nCoV) outbreak.

PURPOSE: The coronavirus disease (COVID-19) pandemic has evolved into a formidable healthcare crisis. Ophthalmologists are at daily personal risk of acquiring and transmitting the virus. Implementation of official practical and protective guidelines can be challenging and is often absent. The purpose of this study was to describe the status of ophthalmology practice in Israel, at the early stages of the outbreak. METHODS: A 17-item questionnaire was distributed to ophthalmologists practicing in Israel. Data was obtained regarding demographics and clinical and surgical practice during the pandemic. RESULTS: One hundred and sixty-seven ophthalmologists completed the survey from all regions of Israel. The survey was distributed during the early stages of the outbreak. At this time, no official government guidelines were in place. Most respondents reported no reduction of elective clinic visits and surgeries and no utilization of triage questionnaires. COVID-19 guidelines were reportedly promulgated to hospital ophthalmologists but not to community and private physicians. Personal protective equipment (PPE) measures were reportedly utilized; however, many respondents often acquired them individually. A majority of respondents advocated that healthcare institutions limit clinic and surgery services to emergency services. CONCLUSION: During the critical early stages of the COVID-19 outbreak in Israel, this study emphasizes the delay in development of emergency guidelines, necessary to protect patients and ophthalmologists from this highly transmissible disease.

Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer Thinning in Patients with Type-1 Gaucher Disease.

Type-1 Gaucher disease (GD1) is considered to be non- neuronopathic however recent evidence of neurological involvement continues to accumulate. There is limited evidence of retinal abnormalities in GD1. The purpose of this study was to evaluate the retinal findings of patients with GD1. Thirty GD1 individuals and 30 healthy volunteers between the ages 40-75 years were prospectively enrolled. Macular and optic nerve optical coherence tomography (OCT) scans of both eyes of each patient were performed and thickness maps were compared between groups. Patients with a known neurodegenerative disease, glaucoma, high myopia and previous intraocular surgeries were excluded. It was shown that patients with GD1 presented with higher incidence of abnormal pRNFL OCT scan and showed significantly thinner areas of pRNFL and macular ganglion cell complex (GCC) when compared to a healthy control population. Changes in retinal thickness were not associated with GD1 genotype, treatment status, disease monitoring biomarker (lyso-Gb1) and severity score index (Zimran SSI). Further investigations are needed to determine whether these findings possess functional visual implications and if retinal thinning may serve as biomarker for the development of future neurodegenerative disease in this population.

Glucosylsphingosine (lyso-Gb1) as a Biomarker for Monitoring Treated and Untreated Children with Gaucher Disease.

The role of glucosylsphingosine (lyso-Gb1), a downstream metabolic product of glucosylceramide, for monitoring treated and untreated children with Gaucher disease (GD) has not yet been studied. We reviewed the clinical charts of 81 children (<18 years), 35 with mild type 1 GD (GD1), 34 with severe GD1 and 12 with type 3 GD (GD3), followed at Shaare Zedek Medical Center between 2014-2018. Disease severity for GD1 was based on genotypes. Forty children (87%) with severe GD1 and GD3 received enzyme replacement therapy (ERT) compared to two children (6%) with mild GD1. Lyso-Gb1 measurements were conducted on dried blood spot samples taken at each clinic visit. Lyso-Gb1 levels were significantly lower in children with mild compared to severe GD1 (p = 0.009). In untreated children, lyso-Gb1 levels were inversely correlated with platelet counts. During follow-up, lyso-Gb1 increased in almost 50% of untreated children, more commonly in younger children. In treated children, lyso-Gb1 levels were inversely correlated with hemoglobin levels. The increase of lyso-Gb1 while receiving ERT, seen in eight children, was partly associated with compliance and weight gain. Lyso-Gb1 seems to be a useful biomarker for monitoring children with GD and should be included in the routine follow-up. Progressive increase in lyso-Gb1 levels in untreated children suggests ERT initiation.

Gne depletion during zebrafish development impairs skeletal muscle structure and function.

GNE Myopathy is a rare recessively inherited neuromuscular disorder caused by mutations in the GNE gene, which codes for the key enzyme in the metabolic pathway of sialic acid synthesis. The process by which GNE mutations lead to myopathy is not well understood. By in situ hybridization and gne promoter-driven fluorescent transgenic fish generation, we have characterized the spatiotemporal expression pattern of the zebrafish gne gene and have shown that it is highly conserved compared with the human ortholog. We also show the deposition of maternal gne mRNA and maternal GNE protein at the earliest embryonic stage, emphasizing the critical role of gne in embryonic development. Injection of morpholino (MO)-modified antisense oligonucleotides specifically designed to knockdown gne, into one-cell embryos lead to a variety of phenotypic severity. Characterization of the gne knockdown morphants showed a significantly reduced locomotor activity as well as distorted muscle integrity, including a reduction in the number of muscle myofibers, even in mild or intermediate phenotype morphants. These findings were further confirmed by electron microscopy studies, where large gaps between sarcolemmas were visualized, although normal sarcomeric structures were maintained. These results demonstrate a critical novel role for gne in embryonic development and particularly in myofiber development, muscle integrity and activity.

Survival-apoptosis associated signaling in GNE myopathy-cultured myoblasts.

GNE Myopathy (GNEM) is a neuromuscular disorder caused by mutations in the GNE gene. It is a slowly progressive distal and proximal muscle weakness sparing the quadriceps. In this study, we applied our model of mutated M743T GNE enzyme skeletal muscle-cultured myoblasts and paired healthy controls to depict the pattern of signaling proteins controlling survival and/or apoptosis of the PI3K/AKT, BCL2, ARTS/XIAP pathways, examined the effects of metabolic changes/stimuli on their expression and activation, and their potential role in GNEM. Immunoblot analysis of the GNEM myoblasts indicated a notable increased level of activated PTEN and PDK1 and a trend of relative differences in the expression and activation of the examined signaling molecules with variability among the cultures. ANOVA analysis showed a highly significant interaction between the level of PTEN and the patients groups. In parallel, the interaction between the level of BCL2, BAX and PTEN with the specific PI3K/AKT inhibitor-LY294002 was highly significant for BCL2 and nearly significant for PTEN and BAX. The pattern of the ARTS/XIAP signaling proteins of GNEM and the paired controls was variable, with no significant differences between the two cell types. The response of the GNEM cells to the metabolic changes/stimuli: serum depletion and insulin challenge, as indicated by expression of selected signaling proteins, was variable and similar to the control cells. Taken together, our observations provide a clearer insight into specific signaling molecules influencing growth and survival of GNEM muscle cells.

The Bone Biomarker of Quantitative Chemical Shift Imaging in Patients with Type 1 Gaucher Disease Receiving Low-Dose Long-Term Enzyme Replacement Therapy.

Quantitative chemical shift imaging (QCSI) is the most sensitive imaging biomarker to assess bone marrow involvement in Gaucher disease. Widespread QCSI use is limited by test availability. Anecdotal reports describe two patients demonstrating significant improvement in fat fraction (FF) assessed by QCSI following a switch from imiglucerase to taliglucerase alfa. This analysis evaluated bone marrow involvement in adults with Type 1 Gaucher disease receiving low-dose enzyme replacement therapy (ERT) with imiglucerase and/or velaglucerase alfa. We report baseline data for 30 patients meeting eligibility criteria. Median (range) duration and dose of ERT were 18 (5-26) years and 30 (30-60) U/kg/month, respectively. Low FF scores (<0.30) were observed for seven patients (23%; 95% confidence interval, 10-42%) and were more common in females (n = 6) versus males (n = 1; p < 0.025); one female was menopausal. These baseline data demonstrate that prolonged low-dose ERT with imiglucerase or velaglucerase alfa led to an adequate bone response, assessed by QCSI, in the majority of patients. A minority of such patients with suboptimal bone response require therapeutic change. The next phase of the study will address the effect of switching to taliglucerase alfa on bone status for patients with less than optimal QCSI scores (<0.30).

Real-Life Experience with Oral Eliglustat in Patients with Gaucher Disease Previously Treated with Enzyme Replacement Therapy.

Three types of enzyme replacement therapies (ERTs) and two substrate reduction therapies (SRTs) are approved for symptomatic patients with type 1 Gaucher disease (GD1). Eliglustat is the second SRT approved, yet the first to be approved as first-line therapy for any adult patients with compatible CYP2D6 metabolizer genotype. Herein we report safety and efficacy data of the first 29 patients switched from ERT to eliglustat from the Gaucher Unit at Shaare Zedek Medical Center (SZMC) between 07/2017 and 06/2022; the median (range) time on ERT was 13 (0.66-30) years, and the median (range) time on eliglustat was 7 (1-52) months. Most patients switched due to oral preference or sub-optimal response to low-dose ERT. Twelve patients stopped eliglustat after a median (range) of 4 (1-18) months; 11 due to adverse events (AEs) and one due to personal request. There were no drug-related serious AEs and no drug-related cardiac events. Most AEs were mild and transient, mainly dyspepsia. Efficacy achievements were reflected by maintaining stability. We concluded that switching from ERT to eliglustat is safe if choosing the appropriate patients. Reassuring patients to tolerate early AEs may reduce discontinuation. Following the response and compliance to therapy is important to ensure long-term efficacy.

Platelet Activation and Reactivity in a Large Cohort of Patients with Gaucher Disease.

OBJECTIVES: Patients with Gaucher disease (GD) are at increased risk of bleeding and have varying degrees of thrombocytopenia, making the analysis of platelet function difficult. This study aimed to provide a clinically relevant quantitative assessment of platelet function and determine its relationship with bleeding and GD-related data. METHODS: Unstimulated and stimulated platelet function was measured by whole blood flow cytometry of platelet surface-activated αIIbß3 integrin (detected with monoclonal antibody PAC1), P-selectin (CD62P), and lysosomal-associated membrane protein (LAMP3/CD63) in 149 GD patients. RESULTS: GD patients had a higher level of unstimulated CD63 expression than healthy subjects, which was mildly correlated with glucosylsphingosine (lyso-Gb1) levels (r = 0.17, p-value = 0.042). Splenectomized GD patients had a higher level of unstimulated αIIbß3 integrin and P-selectin expression. Reduced platelet reactivity (-2 standard deviation of reference range) was found in 79 (53%, 95% confidence interval [CI]: 44-61%) patients, of whom 10 (6.7%, 95% CI: 3.3-12%) had more severe platelet dysfunction. In a multivariate model, only lyso-Gb1 levels were associated with the more severe platelet dysfunction. Fifty-four (49%) of 128 adult patients who completed the bleeding tendency questionnaire reported positive bleeding history. In a multivariate logistic model, older age (odds ratio [OR]: 1.05, 95% CI: 1.01-1.1) and low P-selectin reactivity (OR: 2.03, 95% CI: 1.25-3.35) were associated with more than one bleeding manifestation. CONCLUSION: Flow cytometry enables the study of platelet function in thrombocytopenic GD patients. A platelet degranulation defect, but not αIIbß3 integrin activation defect, is associated with clinical bleeding. In vivo increased CD63 expression may be related to GD-related inflammation.

Pre Clinical Assessment of AAVrh74.MCK.GNE Viral Vector Therapeutic Potential: Robust Activity Despite Lack of Consistent Animal Model for GNE Myopathy.

BACKGROUND: GNE myopathy is a unique adult onset rare neuromuscular disease caused by recessive mutations in the GNE gene. The pathophysiological mechanism of this disorder is not well understood and to date, there is no available therapy for this debilitating disease. We have previously established proof of concept that AAV based gene therapy can effectively deliver the wild type human GNE into cultured muscle cells from human patients and in mice, using a CMV promoter driven human wild type GNE plasmid delivered through an adeno associated virus (AAV8) based platform. OBJECTIVE: In the present study we have generated a muscle specific GNE construct, driven by the MCK promoter and packaged with the AAVrh74 serotype for efficacy evaluation in an animal model of GNE Myopathy. METHODS: The viral vector was systemically delivered at 2 doses to two age groups of a Gne-/- hGNED207V Tg mouse described as a preclinical model of GNE Myopathy, and treatment was monitored for long term efficacy. RESULTS: In spite of the fact that the full described characteristics of the preclinical model could not be reproduced, the systemic injection of the rAAVrh74.MCK.GNE viral vector resulted in a long term presence and expression of human wt GNE in the murine muscles and in some improvements of their mild phenotype. The Gne-/- hGNED207V Tg mice are smaller from birth, but cannot be differentiated from littermates by muscle function (grip strength and Rotarod) and their muscle histology is normal, even at advanced age. CONCLUSIONS: The rAAVrh74.MCK.GNE vector is a robust tool for the development of GNE Myopathy therapies that supply the intact GNE. However, there is still no reliable animal model to fully assess its efficacy since the previously developed Gne-/- hGNED207V Tg mice do not present disease characteristics.

Parkinson's Clustering in Families of Non-Neuronopathic N370S GBA Mutation Carriers Indicates the Presence of Genetic Modifiers.

Low penetrance of Parkinson's disease (PD) associated with GBA pathogenic variants indicates the presence of modifiers genes. Clusters of PD cases in certain families with GBA variants would serve as a strong evidence for the clinical relevance of such modifiers. We studied eight family trees of non-Parkinsonian, GBA-N370S homozygote, Gaucher probands, with multiple cases of PD. Differences in PD risk associated with different GBA variants were balanced by variant homozygosity. In these families, all PD cases stemmed from only one of the proband's parents. This observation provides a direct epidemiological evidence for genetic modifiers determining PD risk in GBA variant carriers.