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.

Phase 1 Healthy Volunteer Study of AL01211, an Oral, Non-brain Penetrant Glucosylceramide Synthase Inhibitor, to Treat Fabry Disease and Type 1 Gaucher Disease

Glycosphingolipid (GSL) storage diseases are caused by deficiencies in the enzymes that metabolize different GSLs in the lysosome. Glucosylceramide synthase (GCS) inhibitors reduce GSL production and have potential to treat multiple GSL storage diseases. AL01211 is a potent, oral GCS inhibitor being developed for the treatment of Type 1 Gaucher disease and Fabry disease. AL01211 has minimal central nervous system penetration, allowing for treatment of peripheral organs without risking CNS-associated adverse effects. AL01211 was evaluated in a Phase 1 healthy volunteer study with single ascending dose (SAD) and multiple ascending dose (MAD) arms, to determine safety, pharmacokinetics including food effect, and pharmacodynamic effects on associated GSLs. In the SAD arm, AL01211 showed a Tmax of approximately 3.5 hours, mean clearance (CL/F) of 130.1 L/h, and t1/2 of 39.3 hours. Consuming a high-fat meal prior to dose administration reduced exposures 3.5-5.5-fold, indicating a food effect. In the MAD arm, AL01211 had an approximately 2-fold accumulation, reaching steady-state levels by 10 days. Increasing exposure inversely correlated with a decrease in GSL with plasma glucosylceramide and globotriacylceramide reduction from baseline levels, reaching 78% and 52% by day 14, respectively. AL01211 was generally well-tolerated with no AL01211 associated serious adverse events, thus supporting its further clinical development.

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.

Gaucher Disease: A Glance from a Medicinal Chemistry Perspective

Rare diseases are particular pathological conditions affecting a limited number of people and few drugs are known to be effective as therapeutic treatment. Gaucher disease, caused by a deficiency of the lysosomal enzyme glucocerebrosidase, belongs to this class of disorders, and it is considered the most common among the Lysosomal Storage Diseases. The two main therapeutic approaches are the Enzyme Replacement Therapy (ERT) and the Substrate Reduction Therapy (SRT). ERT, consisting in replacing the defective enzyme by administering a recombinant enzyme, is effective in alleviating the visceral symptoms, hallmarks of the most common subtype of the disease whereas it has no effects when symptoms involve CNS, since the recombinant protein is unable to significantly cross the Blood Brain Barrier. The SRT strategy involves inhibiting glucosylceramide synthase (GCS), the enzyme responsible for the production of the associated storage molecule. The rational design of new inhibitors of GCS has been hampered by the lack of either the crystal structure of the enzyme or an in-silico model of the active site which could provide important information regarding the interactions of potential inhibitors with the target, but, despite this, interesting results have been obtained and are herein reviewed.

Multivalent pyrrolidines acting as pharmacological chaperones against Gaucher disease

A concise asymmetric synthesis of clickable enantiomeric pyrrolidines was achieved using Crabbé-Ma allenation. The synthesized iminosugars were grafted by copper-free strain-promoted alkyne-azide cycloaddition onto phosphorus dendrimers. The hexavalent and dodecavalent pyrrolidines were evaluated as β-glucocerebrosidase inhibitors. The level of inhibition suggests that monofluorocyclooctatriazole group may contribute to the affinity for the protein leading to potent multivalent inhibitors. Docking studies were carried out to rationalize these results. Then, the iminosugars clusters were evaluated as pharmacological chaperones in Gaucher patients' fibroblasts. An increase in β-glucocerebrosidase activity was observed with hexavalent and dodecavalent pyrrolidines at concentrations as low as 1 µM and 0.1 µM, respectively. These iminosugar clusters constitute the first example of multivalent pyrrolidines acting as pharmacological chaperones against Gaucher disease.

Soluble mannose receptor: A potential biomarker in Gaucher disease

PURPOSE

Soluble mannose receptor (sMR) relates to mannose receptor expression on macrophages, and is elevated in inflammatory disorders. Gaucher disease (GD) has altered macrophage function and utilises mannose receptors for enzyme replacement therapy (ERT) endocytosis. sMR has not previously been studied in GD.

METHODS

sMR was measured by ELISA and correlated with GD clinical features including spleen and liver volume, haemoglobin and platelet count, bone marrow burden (BMB) scores and immunoglobulin levels. sMR was compared with biomarkers of GD: chitotriosidase, lyso-GL1, PARC, CCL3, CCL4, osteoactivin, serum ACE and ferritin.

RESULTS

Median sMR in untreated GD patients was 303.0 ng/mL compared to post-treatment 190.9 ng/mL (p = .02) and healthy controls 202 ng/mL. Median sMR correlated with median spleen volume 455 mL (r = .70, p = .04), liver volume 2025 mL (r = .64, p = .04), BMB 7 (r = .8, p = .03), IgA 1.9 g/L (r = .54, p = .036), IgG 9.2 g/L (r = .57, p = .027), IgM 1.45 g/L (r = .86, p < .0001), with inverse correlation to median platelet count of 125 × 109/L (r = -.47, p = .08) and haemoglobin of 137 g/L (r = -.77, p = .0008). sMR correlated with established biomarkers: osteoactivin 107.8 ng/mL (r = .58, p = .0006), chitotriosidase 3042 nmol/mL/h (r = .52, p = .0006), PARC 800 ng/mL (r = .67, p = .0068), ferritin 547 μg/L (r = .72, p = .002) and CCL3 50 pg/mL (r = .67, p = .007).

CONCLUSIONS

sMR correlates with clinical features and biomarkers of GD and reduces following therapy.

Lysosomal storage, impaired autophagy and innate immunity in Gaucher and Parkinson's diseases: insights for drug discovery

Impairment of autophagic-lysosomal pathways is increasingly being implicated in Parkinson's disease (PD). GBA1 mutations cause the lysosomal storage disorder Gaucher disease (GD) and are the commonest known genetic risk factor for PD. GBA1 mutations have been shown to cause autophagic-lysosomal impairment. Defective autophagic degradation of unwanted cellular constituents is associated with several pathologies, including loss of normal protein homeostasis, particularly of α-synuclein, and innate immune dysfunction. The latter is observed both peripherally and centrally in PD and GD. Here, we will discuss the mechanistic links between autophagy and immune dysregulation, and the possible role of these pathologies in communication between the gut and brain in these disorders. Recent work in a fly model of neuronopathic GD (nGD) revealed intestinal autophagic defects leading to gastrointestinal dysfunction and immune activation. Rapamycin treatment partially reversed the autophagic block and reduced immune activity, in association with increased survival and improved locomotor performance. Alterations in the gut microbiome are a critical driver of neuroinflammation, and studies have revealed that eradication of the microbiome in nGD fly and mouse models of PD ameliorate brain inflammation. Following these observations, lysosomal-autophagic pathways, innate immune signalling and microbiome dysbiosis are discussed as potential therapeutic targets in PD and GD. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.

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.

Identification of ß-Glucocerebrosidase Activators for Glucosylceramide hydrolysis

Several novel chemical series were identified that modulate glucocerebrosidase (GCase). Compounds from these series are active on glucosylceramide, unlike other known GCase modulators. We obtained GCase crystal structures with two compounds that have distinct chemotypes. Positive allosteric modulators bind to a site on GCase and induce conformational changes, but also induce an equilibrium state between monomer and dimer.

Rapid and long-lasting efficacy of high-dose ambroxol therapy for neuronopathic Gaucher disease: A case report and literature review

Gaucher disease (GD) is a lysosomal storage disorder caused by a deficiency in the GBA1-encoded enzyme, β-glucocerebrosidase. Enzyme replacement therapy is ineffective for neuronopathic Gaucher disease (nGD). High-dose ambroxol has been administered as an alternative treatment for a group of patients with nGD. However, little is known about the clinical indication and the long-term outcome of patients after ambroxol therapy. We herein report a case of a female patient who presented with a progressive disease of GD type 2 from 11 months of age and had the pathogenic variants of p.L483P (formerly defined as p.L444P) and p.R502H (p.R463H) in GBA1. A combined treatment of imiglucerase with ambroxol started improving the patient's motor activity in 1 week, while it kept the long-lasting effect of preventing the deteriorating phenotype for 30 months. A literature review identified 40 patients with nGD, who had received high-dose ambroxol therapy. More than 65% of these patients favorably responded to the molecular chaperone therapy, irrespective of p.L483P homozygous, heterozygous or the other genotypes. These results highlight the long-lasting effect of ambroxol-based chaperone therapy for patients with an expanding spectrum of mutations in GBA1.

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.

Posterior Segment Changes in Gaucher Disease

This case report discusses posterior segment characteristics in a patient aged 24 years with low vision and a history of Gaucher disease.

Identification of GM1-Ganglioside Secondary Accumulation in Fibroblasts from Neuropathic Gaucher Patients and Effect of a Trivalent Trihydroxypiperidine Iminosugar Compound on Its Storage Reduction

Gaucher disease (GD) is a rare genetic metabolic disorder characterized by a dysfunction of the lysosomal glycoside hydrolase glucocerebrosidase (GCase) due to mutations in the gene GBA1, leading to the cellular accumulation of glucosylceramide (GlcCer). While most of the current research focuses on the primary accumulated material, lesser attention has been paid to secondary storage materials and their reciprocal intertwining. By using a novel approach based on flow cytometry and fluorescent labelling, we monitored changes in storage materials directly in fibroblasts derived from GD patients carrying N370S/RecNcil and homozygous L444P or R131C mutations with respect to wild type. In L444P and R131C fibroblasts, we detected not only the primary accumulation of GlcCer accumulation but also a considerable secondary increase in GM1 storage, comparable with the one observed in infantile patients affected by GM1 gangliosidosis. In addition, the ability of a trivalent trihydroxypiperidine iminosugar compound (CV82), which previously showed good pharmacological chaperone activity on GCase enzyme, to reduce the levels of storage materials in L444P and R131C fibroblasts was tested. Interestingly, treatment with different concentrations of CV82 led to a significant reduction in GM1 accumulation only in L444P fibroblasts, without significantly affecting GlcCer levels. The compound CV82 was selective against the GCase enzyme with respect to the β-Galactosidase enzyme, which was responsible for the catabolism of GM1 ganglioside. The reduction in GM1-ganglioside level cannot be therefore ascribed to a direct action of CV82 on β-Galactosidase enzyme, suggesting that GM1 decrease is rather related to other unknown mechanisms that follow the direct action of CV82 on GCase. In conclusion, this work indicates that the tracking of secondary storages can represent a key step for a better understanding of the pathways involved in the severity of GD, also underlying the importance of developing drugs able to reduce both primary and secondary storage-material accumulations in GD.

pH-Responsive Trihydroxylated Piperidines Rescue The Glucocerebrosidase Activity in Human Fibroblasts Bearing The Neuronopathic Gaucher-Related L444P/L444P Mutations in GBA1 Gene

Engineering bioactive iminosugars with pH-responsive groups is an emerging approach to develop pharmacological chaperones (PCs) able to improve lysosomal trafficking and enzymatic activity rescue of mutated enzymes. The use of inexpensive l-malic acid allowed introduction of orthoester units into the lipophilic chain of an enantiomerically pure iminosugar affording only two diastereoisomers contrary to previous related studies. The iminosugar was prepared stereoselectively from the chiral pool (d-mannose) and chosen as the lead bioactive compound, to develop novel candidates for restoring the lysosomal enzyme glucocerebrosidase (GCase) activity. The stability of orthoester-appended iminosugars was studied by 1 H NMR spectroscopy both in neutral and acidic environments, and the loss of inhibitory activity with time in acid medium was demonstrated on cell lysates. Moreover, the ability to rescue GCase activity in the lysosomes as the result of a chaperoning effect was explored. A remarkable pharmacological chaperone activity was measured in fibroblasts hosting the homozygous L444P/L444P mutation, a cell line resistant to most PCs, besides the more commonly responding N370S mutation.

Treatment-naive and post-treatment glucosylsphingosine (lyso-GL1) levels in a cohort of pediatric patients with Gaucher disease

Glucosylsphingosine (lyso-GL1) is a biomarker used to monitor disease and treatment response in Gaucher disease. Data from adults show that higher values of lyso-GL1 are associated with increased disease progression, however similar data in the pediatric population is lacking. In a cohort of pediatric patients, we present a relationship between lyso-GL1 value and Gaucher type, age, and treatment response. Data from this study may serve as a reference for providers monitoring children with Gaucher disease.

Enhancing access to treatment for Gaucher disease in India: The need for indigenous manufacturing

Gaucher disease (GD) is a prevalent lysosomal storage disorder (LSD) that significantly impacts individuals' lives. However, the exorbitant prices of GD medications pose a major hurdle in ensuring widespread availability and affordability of treatment in India. The country heavily relies on imported medications, leading to high costs and limited access for many patients. This article aims to address this issue by advocating for the establishment of indigenous manufacturing capabilities for GD medicines in India. Through an examination of the current landscape of GD treatment, including the availability, affordability, and challenges associated with imported medications, this article highlights the urgent need for localized production. By focusing on the potential benefits of indigenous manufacturing, such as reduced costs, increased accessibility, and enhanced availability, this research aims to provide insights and recommendations to policymakers, healthcare professionals, and relevant stakeholders. The findings underscore the importance of developing domestic manufacturing capabilities to address the affordability and accessibility challenges faced by GD patients in India. The research also emphasizes the potential positive impact on the healthcare system, the pharmaceutical industry, and the overall well-being of individuals with GD. Ultimately, this article seeks to stimulate discussions and actions towards creating a sustainable framework for indigenous manufacturing of GD medicines, thereby improving the lives of those affected by this rare and debilitating condition.

Real life data: follow-up assessment on Spanish Gaucher disease patients treated with eliglustat. TRAZELGA project

BACKGROUND

The availability of multiple treatments for type 1 Gaucher disease increases the need for real-life studies to evaluate treatment efficacy and safety and provide clinicians with more information to choose the best personalized therapy for their patients.

AIMS

To determine whether treatment with eliglustat produces, in adult GD1 patients, ans optimal response in daily clinical practice.

METHODS

We designed a real-life study with 2 years of follow-up (TRAZELGA [GEE-ELI-2017-01]) to uniformly evaluate the response and adverse events to eliglustat treatment. This study, conducted in 30 patients across Spain and previously treated with other therapies, included the evaluation of safety and efficacy by assessing visceral enlargement, bone disease (DEXA and T and Z scores), concomitant treatments and adverse events, as well as a quality of life evaluation (SF-36). In addition, the quantification of classical biomarkers (chitotriosidase activity, CCL18/PARC and glucosylsphingosine (GluSph)) and new candidates for GD biomarkers (YKL-40, cathepsin S, hepcidin and lipocalin-2 determined by immunoassay) were also assessed. Non-parametric statistical analysis was performed and p < 0.05 was considered statistically significant.

MAIN RESULTS

Thirty patients were enrolled in the study. The median age was 41.5 years and the male-female ratio was 1.1:1. 84% of the patients had received ERT and 16% SRT as previous treatment. The most common symptoms at baseline were fatigue (42%) and bone pain (38%), no patient had a bone crisis during the study, and two years after switching, 37% had reduced their use of analgesics. Patient-reported outcomes showed a significant increase in physical function scores (p = 0.027) and physical pain scores (p = 0.010). None of the enrolled patients discontinued treatment due to adverse events, which were mild and transient in nature, mainly gastrointestinal and skin dryness. None of the biomarkers show a significant increase or decompensation after switching. CCL18/PARC (p = 0.0012), YKL-40 (p = 0.00004) and lipocalin-2 (p = 0.0155) improved after two years and GluSph after one year (p = 0.0008) and two years (p = 0.0245) of oral therapy.

CONCLUSION

In summary, this real-life study, showed that eliglustat maintains stability and can improve quality of life with few side effects. Significant reductions in classic and other novel biomarkers were observed after two years of therapy.

The international cooperative Gaucher group (ICCG) Gaucher registry

Gaucher disease GD), is a rare lysosomal storage disorder caused by deficient acid β-glucosylceramidase activity and accumulation of glucosylceramide in tissue macrophages. With the 1991 advent of alglucerase enzyme replenishment therapy (ERT), the manufacturer (Genzyme Corporation) created the ICGG Gaucher Registry to collect longitudinal observational "real word" information about GD world-wide in heterogeneous patient populations, to annotate phenotypes and genotypes that define the natural history of GD in untreated patients, and to document and analyze treatment outcomes for alglucerase and any other future treatments. For 32 years, the ICGG Gaucher Registry has functioned as an educational tool for patients, clinicians, and other stakeholders to increase scientific knowledge of GD, to provide practical management guidance, and to positively impact patient care. This paper illustrates how an industry sponsored registry guided by a company independent scientific advisory board has successfully addressed its mission and evolved in step with technologic and scientific advances.

Identification of novel glucocerebrosidase chaperones by unexpected skeletal rearrangement reaction

Compound 5 was identified from a high-throughput screening campaign as a small molecule pharmacological chaperone of glucocerebrocidase (GCase), a lysosomal hydrolase encoded by the GBA1 gene, variants of which are associated with Gaucher disease and Parkinson's disease. Further investigations revealed that compound 5 was slowly transformed into a regio-isomeric compound (6) in PBS buffer, plausibly via a ring-opening at hemiaminal moiety accompanied by subsequent intramolecular CC bond formation. Utilising this unexpected skeletal rearrangement reaction, a series of compound 6 analogues was synthesized which yielded multiple potent GCase pharmacological chaperones with sub-micromolar EC50 values as exemplified by compound 38 (EC50 = 0.14 μM).

Patient reported outcomes of patients with Gaucher disease type 1 treated with eliglustat in real-world settings: The ELIPRO study

INTRODUCTION

Gaucher disease type 1 (GD1) is a rare genetic lysosomal storage disorder. Eliglustat is a first-line oral therapy for adult patients with GD1. The aim of the ELIPRO (ELIglustat Patient Reported Outcomes) study was to assess real-world outcomes of eliglustat treatment for over 1 year in patients with GD1, with a focus on patient-reported outcomes (PROs), including treatment adherence.

METHODS

This was a non-interventional, prospective, multicentric study. Patients were stratified according to their previous time on eliglustat: >6 months (Group1) and ≤ 6 months (Group2). The primary endpoint was adherence to eliglustat, measured by the eight-items Morisky Medication Adherence Scale (MMAS-8; scale of 0-8) at 6 months in Group2. Secondary endpoints were quality of life (QoL) measured by patient input using the European Quality of Life five-dimensional three-level [EQ-5D-3L] questionnaire, fatigue and pain measured by numeric rating scale [NRS; on a scale of 0-10], the evaluation of patient satisfaction level regarding eliglustat treatment measured by Likert scale [scale of 0-7] and treatment adherence at 12 months in both groups. The study also evaluated the safety and effectiveness of eliglustat in the adult GD1 population.

RESULTS

Sixty patients with GD1 (approximatively 52% male, mean age: 46.6 ± 13.9 years) were analyzed: 29 in Group1 and 31 in Group2. GD1 was mostly of mild severity (90%) and 95% of patients had extensive CYP2D6 metabolizer phenotype. Fifty-seven patients had previously received treatment for GD1 (91% enzyme replacement therapy) and 15% were splenectomized. Groups1 and 2 were not necessarily matching for all characteristics. At 6 months, 58% of Group2 patients showed medium adherence (6 < MMAS-8 < 7.75) while 21% showed high adherence (MMAS-8: 8) (mean MMAS-8: 6.7 ± 1.0); similar results were obtained in Group1 (50% showed high compliance, 35% showed medium compliance; mean MMAS-8: 6.8 ± 1.4). The mean MMAS-8 for Group1 and Group2 were 7.1 ± 1.2 (vs 7.0 ± 1.0 at baseline) and 6.5 ± 1.0, respectively, at 12 months. At 12 months, the mean NRS scores in Group1 and Group2 were 72.0 ± 18.5 and 77.3 ± 13.7 for QoL (vs. 71.7 ± 18.4 and 80.2 ± 12.4, respectively at baseline), 4.8 ± 2.6 and 3.6 ± 2.7 for fatigue (vs. 4.6 ± 2.7 and 3.6 ± 2.6, respectively at baseline) and 3.3 ± 2.7 and 2.3 ± 2.3 for pain (vs. 3.3 ± 2.7 and 2.0 ± 2.4, respectively at baseline). GD1 assessments (biological, clinical and imaging parameters) remained stable during 12 months in both groups. At the end of the study, majority (97.4%) of patients were satisfied with their treatment with eliglustat (satisfaction score over 5 out of 7). Sixty-six percent of patients (n = 41) experienced mostly mild adverse events (AE) (including four study withdrawals), of whom 27.4% (n = 17) of patients experienced eliglustat-related AEs. Treatment adherence remained stable during 12 months in both groups.

CONCLUSIONS

Eliglustat treatment compliance was good and sustained, along with overall health state, fatigue and pain levels, which was consistent with overall patients' clinical status. Eliglustat was well tolerated, and had a good safety profile, aligned with a good patient satisfaction. Our study should encourage greater use of PROs for evaluation of impact of the GD treatment on patient's symptoms and well-being.

Effectiveness and Safety of Eliglustat Treatment in Gaucher Disease: Real-life Unicentric Experience

PURPOSE

The therapy and management of Gaucher disease (GD) have radically changed with the use of substrate reduction therapy, of which eliglustat is the most widely known drug, allowing it to overcome the limits of enzyme replacement therapy (ERT). The rarity of GD and the limited use of eliglustat outside clinical trials require further study of its strengths and weaknesses.

METHODS

In this study, we evaluated the effectiveness and safety of eliglustat in a cohort of 12 patients with GD followed up in our center, reporting a reduction in both chitotriosidase (394.3 vs 181.1 nmol/h/mL, P = 0.027) and glucosylsphingosine values (45.1 vs 18.9 ng/mL, P <0.001) after at least 12 months of therapy compared with baseline, regardless of patient demographic characteristics and GD characteristics.

FINDINGS

There were no drug-related serious adverse effects and no drug-related cardiac events. Most adverse events were mild and transient, mainly dyspepsia and abdominal pain. Of interest, we reported an absence of statistical difference in terms of response regarding glucosylsphingosine reduction in relation to naive or prior exposure to ERT (P = 0.296), which was confirmed also when patients were placed in naive and treated groups for <5 vs >5 years (P = 0.667).

IMPLICATIONS

The use of eliglustat immediately after diagnosis may guarantee the best treatment for patients with milder phenotypes or with aggressive disease after an initial stabilization with ERT compared with ERT, which cannot adequately remove the disease burden despite the apparent response, thus potentially reducing future complications caused by substrate deposits.

Gaucher Disease Types I and III Responded Well to Substrate Reduction Therapy Using Eliglustat

Gaucher disease (GD) causes the accumulation of glucocerebrosides in various organs, resulting in hepatosplenomegaly, anemia, decreased platelet counts, and bone disorders. Glucosylsphingosine accumulates in the brain and causes central nervous system (CNS) disorders. GD can be classified into types I (without CNS disorders), II, and III. Substrate reduction therapy (SRT) is an oral therapy that improves patients' quality of life; however, its effect on type III GD is unknown. We administered SRT to GD types I and III patients and found it effective. Malignancy is a late complication of GD, but this is the first report of Barrett adenocarcinoma.

Restoration of β-GC trafficking improves the lysosome function in Gaucher disease

Lysosomes function as a primary site for catabolism and cellular signaling. These organelles digest a variety of substrates received through endocytosis, secretion and autophagy with the help of resident acid hydrolases. Lysosomal enzymes are folded in the endoplasmic reticulum (ER) and trafficked to lysosomes via Golgi and endocytic routes. The inability of hydrolase trafficking due to mutations or mutations in its receptor or cofactor leads to cargo accumulation (storage) in lysosomes, resulting in lysosome storage disorder (LSD). In Gaucher disease (GD), the lysosomes accumulate glucosylceramide because of low β-glucocerebrosidase (β-GC) activity that causes lysosome enlargement/dysfunction. We hypothesize that improving the trafficking of mutant β-GC to lysosomes may improve the lysosome function in GD. RNAi screen using high throughput based β-GC activity assay followed by reporter trafficking assay utilizing β-GC-mCherry led to the identification of nine potential phosphatases. Depletion of these phosphatases in HeLa cells enhanced the β-GC activity by increasing the folding and trafficking of Gaucher mutants to the lysosomes. Consistently, the lysosomes in primary fibroblasts from GD patients restored their β-GC activity upon the knockdown of these phosphatases. Thus, these studies provide evidence that altering phosphatome activity is an alternative therapeutic strategy to restore the lysosome function in GD.

Novel beta-glucocerebrosidase chaperone compounds identified from cell-based screening reduce pathologically accumulated glucosylsphingosine in iPS-derived neuronal cells

The beta-glucocerebrosidase (GBA1) gene encodes the lysosomal beta-glucocerebrosidase (GCase) that metabolizes the lipids glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph). Biallelic loss-of-function mutations in GBA1 such as L444P cause Gaucher disease (GD), which is the most prevalent lysosomal storage disease and is histopathologically characterized by abnormal accumulation of the GCase substrates GlcCer and GlcSph. GD with neurological symptoms is associated with severe mutations in the GBA1 gene, most of which cause impairment in the process of GCase trafficking to lysosomes. Given that recombinant GCase protein cannot cross the blood-brain barrier due to its high molecular weight, it is invaluable to develop a brain-penetrant small-molecule pharmacological chaperone as a viable therapeutic strategy to boost GCase activity in the central nervous system. Despite considerable efforts to screen potent GCase activators/chaperones, cell-free assays using recombinant GCase protein have yielded compounds with only marginal efficacy and micromolar EC50 that would not have sufficient clinical efficacy or an acceptable safety margin. Therefore, we utilized a fluorescence-labeled GCase suicide inhibitor, MDW933, to directly monitor lysosomal GCase activity and performed a cell-based screening in fibroblasts from a GD patient with homozygotic L444P mutations. Here, we identified novel compounds that increase the fluorescence signal from labeled GCase with L444P mutations in a dose-dependent manner. Secondary assays using an artificial cell-permeable lysosomal GCase substrate also demonstrated that the identified compounds augment lysosomal GCase L444P in the fibroblast. Moreover, those compounds increased the total GCase L444P protein levels, suggesting the pharmacological chaperone-like mechanism of action. To further elucidate the effect of the compounds on the endogenous GCase substrate GlcSph, we generated iPSC-derived dopaminergic neurons with a GBA1 L444P mutation that exhibit GlcSph accumulation in vitro. Importantly, the identified compounds reduce GlcSph in iPSC-derived dopaminergic neurons with a GBA1 L444P mutation, indicating that the increase in lysosomal GCase resulting from application of the compounds leads to the clearance of pathologically-accumulated GlcSph. Together, our findings pave the way for developing potent and efficacious GCase chaperone compounds as a potential therapeutic approach for neurological GD.