Qualitative Study of the Patient Experience with Venglustat for Gaucher Disease Type 3 in a Phase 2 Open-Label, Multicenter, Multinational Study (LEAP).

INTRODUCTION: Gaucher disease type 3 (GD3) is a genetic, progressive lysosomal storage disorder characterized by visceral manifestations and chronic neurologic symptoms (e.g., horizontal ophthalmoplegia/supranuclear gaze palsy, ataxia, dystonia). The investigational agent venglustat is being studied in combination with imiglucerase as potential treatment for systemic and neuronopathic manifestations of GD3 in a single-arm, open-label, phase 2 trial (LEAP; N = 11). To understand perceived changes in GD3 symptoms from the perspectives of patients, caregivers, and clinicians, we conducted a qualitative case study of selected LEAP participants. METHODS: Four patients in LEAP (age range, 20-28 years), four of their caregivers, and three clinicians involved in LEAP were interviewed individually by moderators using semi-structured guides. Clinicians' perceptions were based on observation of interviewed patients and those in LEAP who were not interviewed, as well as information provided by other staff involved in LEAP, patients, and caregivers. RESULTS: Reported changes in GD3 symptoms varied among patients and among reporters. Only eye movement was spontaneously mentioned as improved by at least one patient, caregiver, and clinical expert. Symptom improvement also varied in terms of time to improvement. Within the first weeks, improvements were seen in understanding new information or complex instructions, remembering the weekday, eye movement, tremor, and seizures. Changes in alertness, engagement and responsiveness, memory, and concentration appeared after months or a year. Most caregivers and all clinical experts reported greater patient independence (e.g., increased ability to perform activities of daily living or travel independently during the trial) as a perceived treatment effect on a GD3 impact. For one patient who perceived benefits from venglustat therapy, pharmacokinetic analyses during LEAP found low to undetectable venglustat levels in their plasma and cerebrospinal fluid. CONCLUSION: Outcomes from this study provide insights into GD3 symptoms and the early signaling of changes reported during venglustat therapy. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT02843035.

A 10-year follow-up of high-dose ambroxol treatment combined with enzyme replacement therapy for neuropathic Gaucher disease.

High-dose ambroxol therapy combined with ERT in patients with neuropathic Gaucher disease.

Endocrinological and metabolic profile of Gaucher disease patients treated with enzyme replacement therapy.

OBJECTIVES: Gaucher disease (GD) is a lysosomal storage disease caused by glucocerebrosidase (GCase) enzyme deficiency. Gaucher cells transformed from the macrophages by progressive sphingolipid accumulation and infiltrate bone marrow, spleen, liver, and other organs. The accumulation of substrate causes inflammation, compromised cellular homeostasis, and disturbed autophagy. It has been hypothesized that this proinflammatory state of GD leads cytokines and chemokines release. As a result of inflammatory process, the cellular dysfunction caused by disruption of cellular signaling, organelle dysfunction, or autoimmune antibodies may affect endocrine profile of GD patients such as hormone levels, lipid profile, and bone mineral density status. METHODS: A total of 13 patients confirmed to have GD, 12 non-neuronopathic type and one subacute neuronopathic type, were enrolled in our study. RESULTS: The median treatment duration in the enzyme therapy was 13.33 years (9-26 years). At least one endocrinological abnormality was detected in blood tests of nine patients. Hyperinsulinism was the most common finding although fasting blood glucose levels HgbA1c levels were normal in all patients. Two patients had osteopenia, and osteoporosis was detected in two patients. Low HDL levels were detected in six patients, but HDL levels below 23 mg/dL associated with disease severity have been detected in two patients who have not receiving enzyme replacement therapy. None of patients had thyroidal dysfunction. CONCLUSIONS: This study had revealed endocrinological abnormalities in GD patients that have not led any severe morbidity in our patients. However, thyroid hormone abnormalities, insulin resistance, or lipid profile abnormalities may cause unpredictable comorbidities. Endocrinological assessment in GD patients in routine follow-up may prevent possible clinical manifestation in long term as well as can define efficacy of ERT on endocrine abnormalities.

GBA1 as a risk gene for osteoporosis in the specific populations and its role in the development of Gaucher disease.

BACKGROUND: Osteoporosis and its primary complication, fragility fractures, contribute to substantial global morbidity and mortality. Gaucher disease (GD) is caused by glucocerebrosidase (GBA1) deficiency, leading to skeletal complications. This study aimed to investigate the impact of the GBA1 gene on osteoporosis progression in GD patients and the specific populations. METHODS: We selected 8115 patients with osteoporosis (T-score ≤ - 2.5) and 55,942 healthy individuals (T-score > - 1) from a clinical database (N = 95,223). Monocytes from GD patients were evaluated in relation to endoplasmic reticulum (ER) stress, inflammasome activation, and osteoclastogenesis. An in vitro model of GD patient's cells treated with adeno-associated virus 9 (AAV9)-GBA1 to assess GBA1 enzyme activity, chitotriosidase activity, ER stress, and osteoclast differentiation. Longitudinal dual-energy X-ray absorptiometry (DXA) data tracking bone density in patients with Gaucher disease (GD) undergoing enzyme replacement therapy (ERT) over an extended period. RESULTS: The GBA1 gene variant rs11264345 was significantly associated [P < 0.002, Odds Ratio (OR) = 1.06] with an increased risk of bone disease. Upregulation of Calnexin, NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) and Apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) was positively associated with osteoclastogenesis in patients with GD. In vitro AAV9-GBA1 treatment of GD patient cells led to enhanced GBA1 enzyme activity, reduced chitotriosidase activity, diminished ER stress, and decreased osteoclast differentiation. Long-term bone density data suggests that initiating ERT earlier in GD leads to greater improvements in bone density. CONCLUSIONS: Elevated ER stress and inflammasome activation are indicative of osteoporosis development, suggesting the need for clinical monitoring of patients with GD. Furthermore, disease-associated variant in the GBA1 gene may constitute a risk factor predisposing specific populations to osteoporosis.

Advancements in Viral Gene Therapy for Gaucher Disease.

Gaucher disease, an autosomal recessively inherited lysosomal storage disorder, results from biallelic mutations in the GBA1 gene resulting in deficient activity of the enzyme glucocerebrosidase. In Gaucher disease, the reduced levels and activity of glucocerebrosidase lead to a disparity in the rates of formation and breakdown of glucocerebroside and glucosylsphingosine, resulting in the accumulation of these lipid substrates in the lysosome. This gives rise to the development of Gaucher cells, engorged macrophages with a characteristic wrinkled tissue paper appearance. There are both non-neuronopathic (type 1) and neuronopathic (types 2 and 3) forms of Gaucher disease, associated with varying degrees of severity. The visceral and hematologic manifestations of Gaucher disease respond well to both enzyme replacement therapy and substrate reduction therapy. However, these therapies do not improve the neuronopathic manifestations, as they cannot cross the blood-brain barrier. There is now an established precedent for treating lysosomal storage disorders with gene therapy strategies, as many have the potential to cross into the brain. The range of the gene therapies being employed is broad, but this review aimed to discuss the progress, advances, and challenges in developing viral gene therapy as a treatment for Gaucher disease.

Late-onset Myoclonic Seizure in a 78-year-old Woman with Gaucher Disease.

We herein report a 78-year-old woman with Gaucher disease (GD) who was initially diagnosed with GD type 1, had been receiving long-term enzyme replacement therapy since 58 years old, and developed neurological manifestations in her 70s. The neurological manifestations included myoclonic seizures and progressive cognitive decline. Although it is rare for GD patients to first develop neurologic manifestations at such an advanced age, physicians engaged in long-term care for GD patients should be alert for this possibility.

Levodopa-induced dyskinesia in early-onset Parkinson's disease (EOPD) associates with glucocerebrosidase mutation: A next-generation sequencing study in EOPD patients in Thailand.

BACKGROUND: With the benefit of using next-generation sequencing (NGS), our aim was to examine the prevalence of known monogenic causes in early-onset Parkinson's disease (EOPD) patients in Thailand. The association between clinical features, such as levodopa-induced dyskinesia (LID), and genotypes were also explored. METHOD: NGS studies were carried out for EOPD patients in the Tertiary-referral center for Parkinson's disease and movement disorders. EOPD patients who had LID symptoms were enrolled in this study (n = 47). We defined EOPD as a patient with onset of PD at or below 50 years of age. LID was defined as hyperkinetic movements including chorea, ballism, dystonia, myoclonus, or any combination of these movements resulting from levodopa therapy, which could be peak-dose, off-period, or diphasic dyskinesias. RESULTS: Pathogenic variants were identified in 17% (8/47) of the Thai EOPD patients, of which 10.6% (5/47) were heterozygous GBA variants (c.1448T>C in 3 patients and c.115+1G>A in 2 patients), 4.3% (2/47) homozygous PINK1 variants (c.1474C>T) and 2.1% (1/47) a PRKN mutation (homozygous deletion of exon 7). The LID onset was earlier in patients with GBA mutations compared to those without (34.8±23.4 vs 106.2±59.5 months after starting levodopa, respectively, p = 0.001). LID onset within the first 30 months of the disease was also found to be independently associated with the GBA mutation (odds ratio [95% confidence interval] = 25.00 [2.12-295.06], p = 0.011). CONCLUSION: Our study highlights the high prevalence of GBA pathogenic variants in Thai patients with EOPD and the independent association of these variants with the earlier onset of LID. This emphasizes the importance of genetic testing in this population.

Phosphorus Dendrimers for Metal-Free Ligation: Design of Multivalent Pharmacological Chaperones against Gaucher Disease.

The first phosphorus dendrimers built on a cyclotriphosphazene core and decorated with six or twelve monofluorocyclooctyne units were prepared. A simple stirring allowed the grafting of N-hexyl deoxynojirimycin inhitopes onto their surface by copper-free strain promoted alkyne-azide cycloaddition click reaction. The synthesized iminosugars clusters were tested as multivalent inhibitors of the biologically relevant enzymes ß-glucocerebrosidase and acid α-glucosidase, involved in Gaucher and Pompe lysosomal storage diseases, respectively. For both enzymes, all the multivalent compounds were more potent than the reference N-hexyl deoxynojirimycin. Remarkably, the final dodecavalent compound proved to be one of the best ß-glucocerebrosidase inhibitors described to date. These cyclotriphosphazene-based deoxynojirimycin dendrimers were then evaluated as pharmacological chaperones against Gaucher disease. Not only did these multivalent constructs cross the cell membranes but they were also able to increase ß-glucocerebrosidase activity in Gaucher cells. Notably, dodecavalent compound allowed a 1.4-fold enzyme activity enhancement at a concentration as low as 100 nM. These new monofluorocyclooctyne-presenting dendrimers may further find numerous applications in the synthesis of multivalent objects for biological and pharmacological purposes.

Management, vaccination status and COVID-19 morbidity of patients with Gaucher disease in Germany during the COVID-19 pandemic.

BACKGROUND: Continuation of standard management of Gaucher disease (GD) has been challenging during the COVID-19 pandemic, resulting in infrequent/missed infusions and follow-up appointments. Little data are available on the consequences of these changes and on the SARS-CoV-2 vaccinations in German GD patients. METHODS: A survey with 22 questions about GD management during the pandemic was sent to 19 German Gaucher centres. It was answered by 11/19 centres caring for 257 GD patients (almost ¾ of the German GD population); 245 patients had type 1 and 12 had type 3 GD; 240 were ≥ 18 years old. RESULTS: Monitoring intervals were prolonged in 8/11 centres from a median of 9 to 12 months. Enzyme replacement therapy (ERT) was changed to home ERT in 4 patients and substituted by oral substrate reduction therapy (SRT) in 6 patients. From March 2020 to October 2021, no serious complications of GD were documented. Only 4 SARS-CoV-2 infections were reported (1.6%). Two infections were asymptomatic and two mild; all occurred in adult type 1, non-splenectomized patients on ERT. Vaccination rate in adult GD was 79.5% (95.3% mRNA vaccines). Serious vaccination complications were not reported. CONCLUSIONS: The COVID-19 pandemic has lowered the threshold for switching from practice- or hospital-based ERT to home therapy or to SRT. No major GD complication was documented during the pandemic. Infection rate with SARS-CoV-2 in GD may rather be lower than expected, and its severity is mild. Vaccination rates are high in GD patients and vaccination was well tolerated.

Targeting the GBA1 pathway to slow Parkinson disease: Insights into clinical aspects, pathogenic mechanisms and new therapeutic avenues.

The GBA1 gene encodes the lysosomal enzyme glucocerebrosidase (GCase), which is involved in sphingolipid metabolism. Biallelic variants in GBA1 cause Gaucher disease (GD), a lysosomal storage disorder characterised by loss of GCase activity and aberrant intracellular accumulation of GCase substrates. Carriers of GBA1 variants have an increased risk of developing Parkinson disease (PD), with odds ratio ranging from 2.2 to 30 according to variant severity. GBA1 variants which do not cause GD in homozygosis can also increase PD risk. Patients with PD carrying GBA1 variants show a more rapidly progressive phenotype compared to non-carriers, emphasising the need for disease modifying treatments targeting the GBA1 pathway. Several mechanisms secondary to GCase dysfunction are potentially responsible for the pathological changes leading to PD. Misfolded GCase proteins induce endoplasmic reticulum stress and subsequent unfolded protein response and impair the autophagy-lysosomal pathway. This results in α-synuclein accumulation and spread, and promotes neurodegenerative changes. Preclinical evidence also shows that products of GCase activity can promote accumulation of α-synuclein, however there is no convincing evidence of substrate accumulation in GBA1-PD brains. Altered lipid homeostasis secondary to loss of GCase activity could also contribute to PD pathology. Treatments that target the GBA1 pathway could reverse these pathological processes and halt/slow the progression of PD. These range from augmentation of GCase activity via GBA1 gene therapy, restoration of normal intracellular GCase trafficking via molecular chaperones, and substrate reduction therapy. This review discusses the pathways associated with GBA1-PD and related novel GBA1-targeted interventions for PD treatment.

Interaction with ERp57 is required for progranulin protection against Type 2 Gaucher disease.

Gaucher disease (GD), one of the most common lysosomal storage diseases, is caused by GBA1 mutations resulting in defective glucocerebrosidase (GCase) and consequent accumulation of its substrates ß-glucosylceramide (ß-GlcCer). We reported progranulin (PGRN), a secretary growth factor-like molecule and an intracellular lysosomal protein was a crucial co-factor of GCase. PGRN binds to GCase and recruits Heat Shock Protein 70 (Hsp70) to GCase through its C-terminal Granulin (Grn) E domain, termed as ND7. In addition, both PGRN and ND7 are therapeutic against GD. Herein we found that both PGRN and its derived ND7 still displayed significant protective effects against GD in Hsp70 deficient cells. To delineate the molecular mechanisms underlying PGRN's Hsp70-independent regulation of GD, we performed a biochemical co-purification and mass spectrometry with His-tagged PGRN and His-tagged ND7 in Hsp70 deficient cells, which led to the identification of ERp57, also referred to as protein disulfide isomerase A3 (PDIA3), as a protein that binds to both PGRN and ND7. Within type 2 neuropathic GD patient fibroblasts L444P, bearing GBA1 L444P mutation, deletion of ERp57 largely abolished the therapeutic effects of PGRN and ND7, as manifested by loss of effects on lysosomal storage, GCase activity, and ß-GlcCer accumulation. Additionally, recombinant ERp57 effectively restored the therapeutic effects of PGRN and ND7 in ERp57 knockout L444P fibroblasts. Collectively, this study reports ERp57 as a previously unrecognized binding partner of PGRN that contributes to PGRN regulation of GD.

a-Synuclein and lipids in erythrocytes of Gaucher disease carriers and patients before and after enzyme replacement therapy.

It is well established that patients with Gaucher disease, as well as carriers of the disease have an increased risk for developing Parkinson's disease. A plethora of evidence suggests that disturbed α-Synuclein homeostasis is the link between Gaucher disease and Parkinson's disease. The pathogenic mechanism linking these entities is still a topic of debate and both gain- and loss-of-function theories have been put forward, which however are not mutually exclusive. In the present study we expanded our previous studies to include not only Gaucher disease patients but also Gaucher disease carriers and Gaucher disease patients following Enzyme Replacement Therapy. In these groups we investigated α-Synuclein in red blood cell membranes in association with lipid abnormalities described in Gaucher disease. These included glucosylceramide and its species, glucosylsphingosine, glucosylcholesterol and plasmalogens. Increased oligomerization of α-Synuclein in red blood cell membranes was observed not only in Gaucher disease patients but also in carriers of the disease. There were no qualitative differences in the lipids identified in the groups studied. However, significant quantitative differences compared to controls were observed in Gaucher disease patients but not in Gaucher disease carriers. Enzyme Replacement Therapy reversed the biochemical defects and normalized α-Synuclein homeostasis, providing for the first time evidence in human subjects that such homeostatic dysregulation is reversible. Further studies investigating α-Synuclein status during the differentiation of erythroid progenitors could provide new data on the pathogenic mechanism of α-Synuclein oligomerization in this system.

Direct activation of microglia by ß-glucosylceramide causes phagocytosis of neurons that exacerbates Gaucher disease.

Gaucher disease (GD) is the most common lysosomal storage disease caused by recessive mutations in the degrading enzyme of ß-glucosylceramide (ß-GlcCer). However, it remains unclear how ß-GlcCer causes severe neuronopathic symptoms, which are not fully treated by current therapies. We herein found that ß-GlcCer accumulating in GD activated microglia through macrophage-inducible C-type lectin (Mincle) to induce phagocytosis of living neurons, which exacerbated Gaucher symptoms. This process was augmented by tumor necrosis factor (TNF) secreted from activated microglia that sensitized neurons for phagocytosis. This characteristic pathology was also observed in human neuronopathic GD. Blockade of these pathways in mice with a combination of FDA-approved drugs, minocycline (microglia activation inhibitor) and etanercept (TNF blocker), effectively protected neurons and ameliorated neuronopathic symptoms. In this study, we propose that limiting unrestrained microglia activation using drug repurposing provides a quickly applicable therapeutic option for fatal neuronopathic GD.

Understanding patient and parent/caregiver perceptions on gene therapy in Gaucher disease: an international survey.

BACKGROUND: Gaucher disease is a rare, autosomal recessive genetic disorder. It is caused by a lack of sufficient activity of the lysosomal enzyme known as glucocerebrosidase, which leads to an accumulation of glucocerebroside, a fatty substance, in the spleen, liver, bone marrow, and rarely, the lungs or central nervous system. While there are several treatments available for people with Type 1 Gaucher disease and the visceral aspects of Type 3 Gaucher disease, no cure is present for any type of Gaucher disease. Clinical trials are currently underway to investigate the safety and efficacy of gene therapy in Gaucher disease, which has the potential to become a new type of (curative) treatment in the future. Gene therapy is a relatively new therapeutic approach, and with the desire to keep the community informed about new treatment developments, the International Gaucher Alliance (IGA) set-up a Gaucher disease specific survey to gauge current perceptions. The survey aimed to benchmark understanding of, and the educational needs surrounding, gene therapy among the Gaucher disease community. BODY: An international, online survey was developed, comprising twelve questions ranging from multiple choice, Likert scale, single tick-box, ranking and open questions. The survey was developed following three patient and caregiver focus groups and underwent review from members of the IGA for readability and accuracy before going live to respondents. The survey was available for two months and shared to audiences via specific Gaucher community channels. CONCLUSION: Over 100 patients and parents/caregivers from the Gaucher disease community completed the survey, including people living with Type 1 Gaucher disease (52.88%), people living with Type 3 Gaucher disease (3.85%), parents/caregivers of people living with Type 1, 2 or 3 Gaucher disease (39.42%), and other (3.85%) who were defined as parents of multiple people with Gaucher disease. The survey uncovered various commonalities in perception of gene therapy among all groups, with large knowledge gaps identified on the mode of action, the usefulness of gene therapy and overall understanding of the therapeutic area. This survey provides an overview of the type of information that could be valuable to the Gaucher disease community when developing educational materials.

Splenic Gaucheroma Leading to Incidental Diagnosis of Gaucher Disease in a 46-Year-Old Man with a Rare GBA Mutation: A Case Report.

BACKGROUND: Gaucher disease is a common lysosomal storage disease caused by the deficiency of the ß-glucosidase enzyme, leading to sphingolipid accumulation in the reticuloendothelial system in Gaucher cells. Clinical findings are quite variable and some patients may remain asymptomatic lifelong. However, even when patients have mild symptoms, there is a significant increase in their quality of life with enzyme replacement therapy. We aimed to reveal the relationship between a rare mutation in the Glucosylceramidase Beta (GBA) gene and clinical signs and symptoms. Another aim of the study was to show the effect of enzyme replacement therapy on the quality of life, even in patients with mild symptoms. CASE PRESENTATION: Here, we report a 46-year-old male diagnosed with Gaucher disease based on splenic Gaucheromas incidentally discovered in a cardiac computerized tomography scan. In GBA gene analysis, the extremely rare R87W mutation was detected in a homozygous state. In retrospect, the patient had nonspecific symptoms such as fatigue and bone pain for a long time, which were substantially ameliorated by enzyme replacement therapy. CONCLUSION: In patients with adult-onset Gaucher disease, the symptoms may be mild, causing significant diagnostic delay. Gaucher disease may be included in the differential diagnosis of abdominal malignancies. Early diagnosis and treatment can improve quality of life and prevent unnecessary procedures.

A Systematic Review and Meta-analyses of Longitudinal Studies on Drug Treatments for Gaucher Disease.

OBJECTIVE: Gaucher disease (GD) is a rare disorder linked to the absence/deficiency of glucocerebrosidase. GD can be treated by enzyme replacement therapy (ERT) and substrate reduction therapy (SRT). The aim of this systematic review (SR) is to assess the effectiveness of drugs used for GD treatment. DATA SOURCES: Searches were conducted in PubMed and Scopus, in April 2021. The search strategies encompassed the name of the disease and of the drug treatments. Manual search was also conducted. STUDY SELECTION AND DATA EXTRACTION: Observational and interventional longitudinal studies evaluating ERT and SRT for GD were included. Single mean meta-analyses were conducted for each drug using R. DATA SYNTHESIS: The initial search retrieved 2246 articles after duplicates were removed. Following screening and eligibility assessment, 68 reports were included. The studies evaluated imiglucerase, velaglucerase alfa, taliglucerase alfa, miglustat, and eliglustat. The results showed that ERT is effective as a treatment in both naïve and experienced patients. Miglustat did not significantly improve blood outcomes in naïve patients and resulted in a decrease in the platelet levels of experienced patients. Eliglustat was mainly assessed for experienced patients and resulted in stable outcome values. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This extensive SR confirms the effectiveness of GD treatments in short- and long-term follow-ups. CONCLUSIONS: The results were favorable for all ERTs and for eliglustat. Based on the assessed evidence, miglustat did not achieved expressive results. However, all evidence should be interpreted considering its limitations and does not replace well-conducted randomized trials.

Long-term effects of eliglustat on skeletal manifestations in clinical trials of patients with Gaucher disease type 1.

PURPOSE: Most patients with Gaucher disease have progressive and often disabling skeletal manifestations. We examined the long-term effect of eliglustat treatment on bone outcomes in clinical trials in adults with Gaucher disease type 1. METHODS: Data from 4 completed phase 2 and 3 trials were evaluated in treatment-naïve patients or patients switching to eliglustat from enzyme replacement therapy (ERT). RESULTS: Overall, 319 of 393 (81%) eliglustat-treated patients remained in their trials until completion or commercial eliglustat became available. Mean eliglustat treatment duration ranged from 3.3 to 6.5 years. In treatment-naïve patients and ERT-switch patients, frequency and severity of bone pain decreased during eliglustat treatment. Mean lumbar spine T-scores shifted from abnormal to normal in treatment-naïve patients and remained in the healthy reference range or improved modestly in ERT-switch patients. Mean total bone marrow burden score shifted from marked-to-severe to moderate in treatment-naïve patients and remained moderate in ERT-switch patients. MIP-1ß (marker of active bone disease) was elevated at baseline and decreased to the healthy reference range in treatment-naïve patients and remained in the healthy reference range among ERT-switch patients. CONCLUSION: These findings confirm the long-term efficacy of eliglustat on skeletal complications of Gaucher disease in treatment-naïve and ERT-switch patients.