From Scientific Evidence to Patient Care

Transcription

1 7 th Gaucher Leadership Forum From Scientific Evidence to Patient Care 31 March - 1 April 2017 Copenhagen, Denmark Report This meeting is sponsored by

2 7 th Gaucher Leadership Forum From Scientific Evidence to Patient Care 31 March - 1 April 2017 Copenhagen, Denmark Report

3 Table of Contents Scientific Steering Committee: Prof Claus Niederau, Katholisches Klinikum Oberhausen, St. Josef-Hospital, Germany Dr Allan Lund, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark Prof Hans Aerts, University of Leiden, The Netherlands Dr Nadia Belmatoug, Beaujon Hospital, Clichy, France Prof Maria Domenica Cappellini, Policlinico Foundation IRCCS, Milan University, Italy Prof Timothy Cox, University of Cambridge, UK Dr Derralynn Hughes, Royal Free London NHS Foundation Trust and University College London, UK Prof Pramod Mistry, Yale University School of Medicine, New Haven, US Dr Neal Weinreb, University of Miami Miller School of Medicine, US Faculty Members: Prof Stefan Karlsson, Lund University, Sweden Prof Timothy Cox, University of Cambridge, UK Dr Derralynn Hughes, Royal Free London NHS Foundation Trust and University College London, UK Prof Hans Aerts, University of Leiden, The Netherlands Dr Seng Cheng, Sanofi Genzyme, Framingham, USA Dr Hanna Rosenbaum, Clalit Clinic, Nazareth, Israel Prof Pramod Mistry, Yale University School of Medicine, New Haven, USA Prof David Kasper, University of Vienna & Archimed Life Science, Austria Prof Maria Domenica Cappellini, Policlinico Foundation IRCCS, Milan University, Italy Prof Andrea Pession, Sant Orsola-Malpighi University Hospital, Bologna, Italy Dr Ellen Sidransky, National Institutes of Health, Bethesda, USA Prof Alessio di Fonzo, Policlinico Hospital of Milan, Italy Dr Judith Peterschmitt, Sanofi Genzyme, Cambridge, USA Prof Neil Weinreb, University of Miami Miller School of Medicine, USA Prof Madhav Dhodapkar, Yale University, New Haven, USA Prof Stephan vom Dahl, University Hospital Düsseldorf, Germany Prof Paige Kaplan, University of Pennsylvania, Philadelphia, USA Prof Anna Tylki-Szymańska, Children s Memorial Health Institute, Warsaw, Poland Prof Magy Abdelwahab, Cairo University Pediatric Hospital, Egypt Dr Eugen Mengel, Children s Hospital, University of Mainz, Germany Dr Nadia Belmatoug, Beaujon Hospital, Clichy, France Prof Elena Lukina, National Research Center for Hematology, Moscow, Russia Introduction 5 Executive Summary 5 Welcome and Introduction 6 Prof Claus Niederau (Germany) and Dr Allan Lund (Denmark) Key note lecture: 8 Development of gene therapy for Gaucher disease Prof Stefan Karlsson (Sweden) Plenary Session 1: Translational Science 9 Underlying immunology in Gaucher disease 9 Dr Derralynn Hughes (UK) Alternative substrates, lipids and other biomarkers 10 Prof Hans Aerts (Netherlands) CNS inhibition 11 Dr Seng Cheng (US) Plenary Session 2: Diagnostic Challenges 13 Examining the gap between prevalence and diagnosis 13 Prof Pramod Mistry (US) Novel fully validated laboratory test for the measurement of glucosylsphingosine (lyso-gl-1) from dried blood spots in Gaucher disease Prof David Kasper (Austria) Approaches in specific situations the Italian experience 14 Prof Maria Domenica Cappellini (Italy) GAU-Ped Study: the chance of early diagnosis for pediatric hematologists/oncologists 15 Prof Andrea Pession (Italy) The enigmatic relationship of glucocerebrosidase and parkinsonism: Clinical and basic science implications Dr Ellen Sidransky (US) Working Group 1: Neurological aspects in Gaucher disease 16 Prof Timothy Cox, Dr Allan Lund, Prof Alessio Di Fonzo, Dr Judith Peterschmitt Working Group 2: Malignancy in Gaucher disease 18 Dr Neal Weinreb, Dr Derralynn Hughes, Prof Madhav Dhodapkar, Prof Stephan vom Dahl The presentations marked above in yellow are not included in this report on request of the presenters, due to data sensitivities. The statements and opinions expressed in this meeting are those of the speakers and are NOT necessarily endorsed by Sanofi Genzyme. All speakers reviewed and approved their presentation summaries included in this document. 2 3

4 Working Group 3: Optimal management of children with Gaucher disease 20 Prof Paige Kaplan, Prof Anna Tylki-Szymañska, Dr Eugen Mengel, Prof Magy Abdelwahab Introduction Working Group 4: Challenging clinical cases in Gaucher disease 23 Dr Nadia Belmatoug, Prof Claus Niederau, Prof Elena Lukina Plenary Session 3: Substrate Reduction Therapy 26 Substrate Reduction Therapy: Real world Experience 26 Prof Pramod Mistry (US) Long-Term Treatment Response to Oral Eliglustat in patients with Gaucher Disease Type 1 27 Prof Elena Lukina (Russia) Practical management of eliglustat therapy in Gaucher disease Type 1 28 Prof Claus Niederau (Germany) Substrate Reduction Therapy Treatment Guidelines 29 Dr Nadia Belmatoug (France) References 32 The statements and opinions expressed in this meeting are those of the speakers and are NOT necessarily endorsed by Sanofi Genzyme. All speakers reviewed and approved their presentation summaries included in this document. The 7 th Gaucher Leadership forum (GLF) was chaired by Professor Claus Niederau (Germany) and hosted by Dr Allan Lund (Denmark). The theme of the meeting was From Scientific Evidence to Patient Care focussing on advancing solutions towards meeting unmet needs in the management of Gaucher Executive summary Plenary sessions: Keynote speaker, Professor Stefan Karlsson (Sweden) reviewed recent advances in gene therapy for Gaucher disease using lentiviral vectors. Promising data in mice could pave the way for clinical trial protocols for type 1 Gaucher disease. Dr Derralynn Hughes (UK) provided a fascinating overview of the evolving understanding of underlying immunology in Gaucher disease. The emerging role of complement may provide a potential therapeutic target for the future. The biochemical functioning of the acid beta glucosidase (glucocerebrosidase or GCase) was at the center of Professor Hans Aert s (Netherlands) presentation which postulated that specific symptoms seen in patients with Gaucher disease could result from hydrolase and transglucosylase activities of mutated GCase and the availability of other acceptors in any given tissue. Addressing central nervous system (CNS) symptoms of neuronopathic Gaucher patients remains a challenge with current therapeutic options. Dr Seng Cheng (USA) outlined ongoing research efforts to develop CNS-penetrative small molecule drugs as a novel approach to treat patients with Gaucherrelated and non-related Parkinsonism. Professor Pramod Mistry (USA) discussed the variety of reasons for the apparent gap between prevalence and diagnosis of Gaucher disease. The majority of published literature has type 1 / N370S as its focus, yet worldwide L444P is the most common mutation and is strongly associated with more severe forms of Gaucher. Developing algorithms to improve the patients. Key aims of the meeting were to promote collaborations and help develop the next generation of clinicians and researchers. The meeting included presentations from international experts in GD and other relevant medical and research fields, together with interactive workshops and opportunities for discussion and networking. diagnosis of Gaucher disease was the subject of two presentations from Italy. Professor Maria Domenica Cappellini presented results of a study involving 33 hematology centers which used an algorithm focussing on splenomegaly and/ or thrombocytopenia as presenting symptoms and GCS activity via dried blood spots (DBS) testing. Professor Andreas Pession presented results using a similar algorithm in pediatric hematology centers. Real world experience with Substrate Reduction Therapy (SRT) was presented by Professor Pramod Mistry (USA) who shared his own center s experience of using eliglustat in over 40 patients over a period of 5 years. Professor Elena Lukina (Russia) presented long term (5 year) data from the Phase 2 and 3 eliglustat clinical trial program including hematological and visceral markers, biomarkers, bone data and safety / tolerability. Practical aspects of eliglustat therapy was the topic presented by Professor Claus Niederau (Germany), with a focus on managing potential drug:drug interactions. Professor Niederau shared his own center s experience of using eliglustat and discussed its place as an alternative first line therapy in eligible patients with type 1 Gaucher disease. Professor Nadia Belmatoug (France) presented an overview of European and US treatment guidelines for the use of eliglustat including how to initiate treatment in newly diagnosed Gaucher type 1 patients, and in patients on ERT who wish to switch to an oral therapy. 4 5

5 Welcome and introduction 2017 Working Groups Neurological aspects of Gaucher disease Gaucher type 1 patients have an increased risk for the development of Parkinson s disease and approximately 10% of patients with Parkinson s has one or more GBA mutation Prodromal symptoms of Parkinson s may be present up to 20 years before a diagnosis, including reduced sense of smell, microphagia, constipation and the presence of Rapid Eye Movement (REM) The cardinal symptoms of Parkinson s disease are resting tremor, bradykinesia and rigidity; a diagnosis is based on presence of two of these signs plus a response to levodopa treatment It is important to reassure Gaucher type 1 patients and families that the vast majority (>90%) will not develop Parkinson s disease Clinical trials are underway to investigate potential disease-modifying therapy for Parkinson s disease in patients carrying a GBA mutation Malignancy in Gaucher disease The increased risk among Gaucher patients of developing MGUS or B-cell malignancies such as multiple myeloma is well known from single center and Registry series; a potential increased risk for solid or multiple tumors needs further evaluation The risk of hepatocellular carcinoma (HCC) is significantly increased in Gaucher patients who have been splenectomized and it can occur without pre-existing cirrhosis. Good management includes ultrasound 6-12 monthly, the measurement of alpha-fetoprotein (AFP) and transient elastography GBA1 mutations are not directly oncogenic; it is the downstream effects of immune dysregulation and dysfunction that promote the emergence of malignancies As understanding of the underlying immunological processes and pathways improve, the potential for targeted therapies should emerge Experiments in mouse models have shown a reduction in anti-lipid antibodies and lipid-reactive clonal immunoglobulins through the use of SRT, but these studies need to be replicated in humanized murine models Optimal management of children with Gaucher disease Homozygosity for L444P is most likely associated with neuronopathic Gaucher disease (GD3) with a very wide phenotypic spectrum GD3 patients from an Egyptian cohort typically presented with mild psychomotor delay, organomegaly and occasionally mild bulbar symptoms, but severe visceral and hematological manifestations were also seen Additional neurological manifestations included oculomotor apraxia, squint and variable cognitive profile. Seizures, including sudden unexplained death from epilepsy, were also seen. Behavioral manifestations were common and in some cases led to a misdiagnosis of ADHD or psychiatric disorders Genotyping remains the gold standard method to predict individual patients clinical outcomes Patients should be monitored every 6-12 months for growth status, visceral volume, hematological parameters, bone and biomarker status. Ideally care should remain under the same physician for consistency and continuity of care Goals of treatment should be individualized for children with Gaucher disease given the dynamic nature of development The development of more sensitive and specific biomarkers such as glucosylosphingosine (Lyso- GL1) shows promise for the future Newborn screening for Gaucher disease could potentially reduce unnecessary diagnostic delays and the potential for disease complications Pre-symptomatic patients should be monitored every 6 months and ERT can be considered if symptoms appear or worsen Challenging clinical cases in Gaucher disease Dr Nadia Belmatoug, Professor Claus Niederau and Professor Elena Lukina discussed several challenging cases across a wide spectrum of clinical situations including: A type 1 Gaucher patient with CML treated with ERT and imatinib A patient presenting with recurrent bone manifestations, diagnosed with bilateral tuberculosis sacrolietis and treated with ERT, anti-tuberculosis therapy and surgery A patient who developed splenic pseudotumors Two patients presenting with dyspnea on exertion; one due to weight gain and the other diagnosed with mild pulmonary hypertension A misdiagnosis of type 1 in a patient with type 3 Gaucher disease Professor Claus Niederau (Katholisches Klinikum Oberhausen, St. Josef-Hospital, Germany) and Dr Allan Lund (Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark) Co-chair and first speaker, Dr Claus Niederau, opened the 7th European Gaucher Leadership Forum (GLF) by welcoming the delegates and faculty to the city of Copenhagen. He explained the GLF was now in its seventh year and was hosting delegates from 47 countries across the world. The theme for 2017 was From Scientific Evidence to Patient Care and focused on advancing the solutions for unmet needs in Gaucher disease, promoting research collaborations and helping to develop the next generation of clinician researchers and scientists. Briefly outlining the program, Dr Niederau explained there would be plenary sessions on basic science and substrate reduction therapy, as well as diagnosis that would focus on closing the gap between prevalence and diagnosis. Interactive working groups on specific aspects of Gaucher diseases would be run allowing the delegates to learn directly from experts in the field and take their knowledge back into their own clinical practice. Co-chair Dr Allan Lund introduced the Danish fairy tale character of Snøvsen who is always getting left behind and used him as an allegory for one of his patients. He had severe hepatosplenomegaly and felt as left behind as Snøvsen, until enzyme replacement therapy improved his visceral parameters. Unfortunately, over time he deteriorated, showing developmental delay and early signs of kyphosis. Dr Lund explained this patient highlights both our recent medical advances in Gaucher diseases and the problems still to be addressed it was these unmet needs that would be the main objective of the meeting. 6 7

6 Key note Lecture Plenary Session 1: Translational Science Chair: Professor Claus Niederau, Katholisches Klinikum Oberhausen, St. Josef-Hospital, Germany Chair: Professor Timothy Cox, University of Cambridge, UK Development of gene therapy for Gaucher disease Professor Stefan Karlsson, Lund University, Sweden Underlying immunology in Gaucher disease Dr Derralynn Hughes, Royal Free London NHS Foundation Trust and University College London, UK Gaucher disease is caused by an inherited deficiency of the enzyme glucocerebrosidase (GCase). Due to the lack of a fully functional enzyme there is progressive build-up of the lipid component glucosylceramide which results in hepatosplenomegaly, cytopenias and bone disease in patients. The keynote lecture discussed recent gene therapy studies in mice that provide evidence for a new option for patients who are unresponsive to enzyme replacement therapy and lack a suitable bone marrow donor. Using a mouse model of Gaucher disease type I 1, where glucosylceramide levels have been artificially increased, gene therapy using gammaretroviral vector with a strong viral promoter to drive acid β-glucosidase gene expression produced decreased glucosylceramide levels in combination with an increase in glucocerebrosidase. Further experiments showed only 6% of myeloid cells are needed to prevent glucosylceramide accumulation and thereby to avoid type 1 Gaucher disease pathology. The gammaretroviral vectors used in these experiments have now been superseded by safer self-inactivating lentiviral vectors (SIN LVs) with the GBA gene under the control of human phosphoglycerate kinase (PGK) and myeloid promoters (CD68), respectively. Using the SIN LVs in mice that had undergone disease induction but were not yet symptomatic, showed after 20 weeks PGK and CD86 promoters significantly increased glucocerebrosidase levels and reduced glucosylceramide almost to the level of the wild type group. A follow up experiment in 6-month-old mice, where Gaucher disease symptoms such as an enlarged spleen had become apparent, showed similar effects on enzyme levels as well as normalized hemoglobin levels and a reversal of splenomegaly. The SIN LVs used showed a minimal risk for insertional mutations as evidenced by a low number of integrations per cell and few insertions close to the transcription start site 2. The future development of these techniques will of course lead into trials in adult Gaucher patients. The aim is to mobilize stem cells in the blood bank, isolate CD34 cells, transduce with SIN LV vectors and return to the patient. Low dose busulfan, which has been used successfully in other diseases, will be given to encourage efficient engraftment for the gene modifying cells. The continued development of these safe lentiviral vectors appears to offer the opportunity to correct the metabolic defect in hematopoietic cells and macrophages and could provide the basis of future clinical gene therapy protocols for type 1 Gaucher disease. Understanding of the pathophysiology of Gaucher Disease (GD) has been driven by clinical phenotyping but understanding of the underlying mechanisms is not so advanced. Blood cell abnormalities in GD include thrombocytopenia and anemia as a result of splenomegaly and bone marrow abnormalities. Immunological problems have not been frequently described. The immune system is relevant to manifestations such as hematological malignancies and bone disease. There are descriptions of abnormalities in both innate and adaptive immunity in GD. Innate immunity refers to nonspecific defence mechanisms that come into play within hours of an antigen s appearance in the body; adaptive immunity refers to antigen-specific immune responses, with immunological memory making future responses to antigen more efficient. Immune abnormalities noted to date in Gaucher disease, include reduced B-cell activity in a patient with serial infections, reduced NK cells and increased inflammatory cytokine production by blood mononuclear cells along with increased tumor necrosis factor (TNF)-α-dependent osteoclastogenesis in patients with bone disease. Storage cells contain glucosylceramide (Gaucher cells), however the lipid component in their membranes is also abnormal. Lipidomic profiling predicted the type of disease, IL-6 production and correlated with immune function of alternatively activated macrophages which express immune-suppressing molecules such as IL-10. The sphingolipid can act as an antigen, and it has been demonstrated that plasma glucosylceramide (including the lyso-metabolites) may stimulate antibody production. The reduction of these lipids by substrate-reduction therapies also reduced antibodies in GBA-/- mice. 3,4 Antigen presentation is also relevant to antibody production. One study 5 showed dendritic cells in patients with GD are decreased in number but functionally normal, whereas another demonstrated upregulation of CD1d and MHC-class II.This suggests that whilst numbers are lower, the capability for antigen presentation is normal through increased expression of those molecules. 6 Plasmacytoid dendritic cells are innate cells found in blood and lymph nodes that secrete inflammatory cytokines in response to viruses Abnormal function of these cells, which improved with therapy, has been seen in GD. 7 Antigen is presented to T-cells and cytokine production ensues depending on the stimulus. T-helper cells Type 2 are usually involved in parasitic or certain allergens infections and have a role in immune tolerance. In GD Th2 cytokines appear decreased (in particular IL-10). 8 Natural Killer cells express Killer-cell immunoglobulin-like receptors (KIR) which interact with MHC-Class I molecules. NK T (Type I) cells react to glucosylceramide, but those found in Gaucher disease (NKT Type II cells) stimulate follicular T helper cells, which play a crucial part in the development of plasma cells and memory B cells. 9 A recent finding is that complement appears to 8 9

7 Plenary Session 1: Translational Science Plenary Session 1: Translational Science have a role in glucosylceramide accumulation and tissue inflammation in GD. In mice deficient in glucocerebrosidase, formation of complement-activating GC-specific IgG autoantibodies, leading to complement activation and C5a generation is evident. A positive feedback loop ensues to further glucosylceramide accumulation. If deficient in both glucocerebrosidase and C5aR1, the mice were protected from early death and Alternative substrates, lipids and other biomarkers Professor Hans Aerts, University of Leiden, The Netherlands glucosylceramide accumulation. 10 Targeting C5aR1 may serve as a treatment option in GD. The key message from this talk was that sphingolipid storage material is itself an important antigen and that the immunology of Gaucher may be relevant outside of sphingolipidoses. activity in cell lines, as well as localization of active GCase in parts of the body. 14 Similar probes were developed that can act with other β-glucosidases, such non-lysosomal glucocerebrosidase, which is found in the membranes of the ER, Golgi and endosomes, but has the catalytic pocket facing the cytosol. 15 This technology can be applied to many other lysosomal enzymes involved in other lysosomal diseases. It is hypothetically possible that the hydrolytic step in the action of GCase can be facilitated by cholesterol instead of water, since the hydroxyl group is favourably placed. This would result in a glucosylated cholesterol molecule. This was shown to be the case in vitro using GlcCer as the donor and naturally occurring cholesterol as the acceptor, giving rise to GlcCho. Evidence for the presence of this compound was then shown in all tissues, but highest in sciatic nerve, lungs and thymus. Formation of GlcCho in vivo is largely through non-lysosomal glucocerebrosidase action and its degradation occurs in the lysosome by GCase. 16 Plasma GlcCho is reduced in treated Gaucher patients. In LSDs where there is an accumulation of cholesterol in the lysosomes (e.g., Niemann-Pick C), GCase can also transglucosylate cholesterol in the lysosome. In conclusion, GlcCer is an intermediary metabolite and a glucose donor. As such, the specific symptoms seen in individuals with Gaucher s could be a result of the specific hydrolase and transglucosylase activities of the mutated GBA and the availability of other acceptors in any given tissue. Glycosphingolipids (GSLs) are a class of membrane lipids, of which glucosylceramide (GlcCer) is a precursor. They play a role in intracellular membrane transport. If defective, some membrane proteins do not reach their intracellular destination resulting in dysfunctional differentiation and maturation of some intracellular organelles. Defects in glycosphingolipid synthesis and degradation interfere with crucial glycosphingolipidmediated signalling mechanisms, leading to diseases such as the lipid storage diseases, obesity and cancer. For example, GlcCer suppresses insulin signalling in adipocytes and, as an anti-apoptotic molecule, can potentially lead to drug resistance if overexpressed in cancer. Professor Aerts talk centred on the biochemical functioning of the enzyme glucocerebrosidase (GCase). This lysosomal hydrolase degrades GlcCer in the lysosomes (removes the glucose) and GBA mutations seen in Gaucher s result in the accumulation of GlcCer in the lysosomes of tissue macrophages. However, knowledge of the mutations in the gene does not accurately predict the severity, prognosis or response to therapy in individuals. In addition, knowledge of the molecules secreted into plasma from Gaucher cells, whilst useful in monitoring therapy efficacy, does not explain the heterogeneous multi-organ manifestations found in patients. Research undertaken in which the enzyme involved in GlcCer synthesis was inhibited in obese rodents, revealed broad positive effects on a number of parameters. 11 So, why does accumulation of GlcCer have such broad pathology, as seen in Gaucher, and reduction of GlcCer produce wide-ranging effects, as seen in the obesity model? The idea proposed was that GlcCer might be a substrate for other enzymes, and indeed, the lipid glucosylsphingosine is formed by the action of a lysosomal acid ceramidase and is excessively produced in Gaucher cells, even more than GlcCer itself. 12 This GlcSph can partially leave the body via bile and urine, but has been shown to increase B-cell proliferation and the risk of myeloma. 13 Thus, alternative lysosomal metabolism of GSLs may cause specific symptoms in lysosomal storage diseases. An example was given for Fabry disease, in which the additional metabolite from GlcSph is globotriaosylsphingosine (lyso-gb3), which has additional toxic effects in the kidney. Probes were developed using a mimic of glucose (cyclophellitol). The molecule can be recognized by GCase as glucose, cleaved from GlcCer and covalently bound to an amino acid of GCase in the first step of catalysis, but because the oxygen is not in the ring of this molecule, but rather an epoxide, the glucose can be not released through the second hydrolytic step. By adding a fluorescent tag, it becomes possible to visualize GCase within cells and thus measuring the amount of enzyme CNS inhibition Dr Seng H Cheng, Sanofi Genzyme, Framingham, USA Enzyme replacement therapy is the standard of care for Gaucher Type 1 patients and substrate reduction therapy represents an alternate, orally-available therapy for some patients. However, despite the availability of ERT and SRT, there remains an unmet medical need as neither therapy effectively addresses all aspects of the disease, especially CNS complications found in neuronopathic Gaucher patients. Developing CNS-permeant small molecule drugs appears to be a rational treatment approach, given the efficacy of substrate replacement therapy in the viscera. New chemical scaffolds that retain the ability to inhibit glucosylceramide synthase and can penetrate the CNS are being developed, including the investigational compound, venglustat (GZ/SAR ). Preclinical studies in rats showed the compound reduced the accumulation of glucosylceramide in the brain by around 40%. Treatment in mouse models of neuronopathic Gaucher disease showed lower levels of accumulation of glucosylceramide and other brain glycolipids, reduced the extent of gliosis and delayed the onset of motor function loss. These effects translated into a significant increase lifespan in treated mice of around 40%. 17 Clearly, if these findings are also realized in clinical studies, it would support the use of substrate reduction therapy as an approach to manage the CNS manifestations associated with patients with type 3 Gaucher disease. Moreover, as glucosylceramide synthase catalyses the first committed step in the synthesis of glycosphingolipids, the benefits of antagonizing this drug target may also be applicable to other neuronopathic lysosomal storage disorders, such as GM2-gangliosidoses

8 Plenary Session 1: Translational Science Plenary Session 2: Diagnostic Challenges Mutations in GBA1 have also been correlated with a heightened risk of developing synucleinopathies, such as Parkinson disease (PD). 18 Patients harboring mutations in GBA1 present higher prevalence and severity of motor and non-motor symptoms. Although the precise mechanisms by which mutations in GBA1 confer these properties remain unclear, a loss-of-function (reduced glucocerebrosidase activity) or a gain-of-toxic function (heightened accumulation of glycosphingolipids) have been proposed as potential contributing factors. Studies have shown that increasing brain glucocerebrosidase activity in the CNS of mouse models with established synucleinopathy reduces the accumulation of glucosylsphingosine and aggregated proteins and corrects memory deficits. 19 In addition, treatment of these same murine models of Gaucher-related PD with venglustat (GZ/SAR402671) to reduce the burden of accumulation of lipids in their CNS also significantly reduced the accumulation of hippocampal aggregates of α-synuclein, ubiquitin and tau. Associated with the lowering of these aggregates is a significant improvement in their memory deficits, which is maintained at nine months post treatment. Comparable results were also seen in mouse models of non-gaucherrelated Parkinsonism suggesting this approach may also have utility in the sporadic form of the disease. 20 In conclusion, augmenting CNS glucocerebrosidase activity and/or lowering glycosphingolipid levels may represent novel approaches to treat patients with both Gaucher-related and non-related Parkinsonism. Chair: Dr Hanna Rosenbaum, Clalit Clinic, Nazareth, Israel Examining the gap between prevalence and diagnosis Professor Pramod K Mistry, Yale University School of Medicine, New Haven, USA Gaucher disease is commonly misdiagnosed as cancer, something that started with Gaucher himself. His initial thesis, based on the abnormal autopsy findings, concluded his patient had a malignant neoplasm localized in the spleen. To this day, malignancy remains a common misdiagnosis. Only 20% of hematologists suspected Gaucher disease in a hypothetical case of a 42-year-old man presenting with the six common signs of Gaucher disease. 1 The confusion is understandable given the overlap in the symptoms with malignant disorders, but misdiagnosis can have severe consequences for the patient. Untreated Gaucher disease is progressive and has been associated with a range of complications including bone disease, bleeding complications, liver disease and a greatly impaired quality of life. 2-4 Biallelic mutation in GBA results in Gaucher disease. The GBA gene locus on chromosome 1q21 is highly gene dense and vulnerable to gene conversion events with close links to the highly homologous GBA pseudogene that harbors several mutations (i.e. L444P and D409H), which, when present in the active GBA, leads to neuronopathic GD. 5 The incidence of GD is estimated at ~ 1 per in the general population but clusters are common, with higher rates seen in Egypt, India, the Middle East and North Africa, and the highest prevalence seen in the Ashkenazi Jewish population (1 in 855). A recent newborn screening program that looked at almost 180,000 infants revealed 4 cases of GD suggesting an incidence of 1 in 45, Based on ICGG Registry data, only ~2500 patients with GD are known in US but the total number of patients are likely to be several times higher than this number as many patients with mild forms of GD do not seek treatment. A recent large screening program in New York city identified 31 N370S homozygotes of whom 65% were asymptomatic, despite most showing early symptoms and effects of their disease (hepatomegaly, splenomegaly, osteopenia etc.) 7 The mutation most commonly associated with type 1 Gaucher disease is N370S (p.n409s), a founder mutation from Eastern Europe. Most of the literature is European/N370S-centric, thus true global prevalence and distribution of mutation types may not accurately be reflected. In fact, the presence of at least one N370S allele precludes neuronopathic GD, which results in the most severe symptoms and reduced life expectancy. Worldwide, the L444P mutation is the most common, and this is strongly associated with the more severe type 2 and 3 Gaucher disease. 8 Screening programs that include Gaucher disease will eventually address the large gap between prevalence and diagnosed patients, particularly in the context of regional phenotypes, but there remains a need for increased awareness and education of physicians

9 Plenary Session 2: Diagnostic Challenges Plenary Session 2: Diagnostic Challenges Approaches in specific situations: the Italian experience Professor Maria Domenica Cappellini, Policlinico Foundation IRCCS, Milan University, Italy GAU-PED study: the chance of early diagnosis for pediatric hematologists/oncologists Professor Andrea Pession, Sant Orsola- Malpighi University Hospital, Bologna, Italy Diagnosis and follow up should be a multidisciplinary approach, but it is not the case. Usually the patient goes to the specialist based on their presenting symptom (rheumatologist, orthopedic, gynecologist etc.) and unfortunately there is little communication between the specialists. This is the main reason for the delay in diagnosis leading to serious and lethal complications. Based on these observations, a different approach is necessary to avoid under-diagnosis and/or diagnostic delays. The complexity and rarity of GD are inherent barriers to diagnosis meaning it is not high on the list of differential diagnoses. Often GD is considered only when all other possibilities have been excluded. So how can the awareness of GD be improved to the point where it is considered earlier in the differential diagnosis? As the presenting signs and symptoms are often related to the hematological manifestations of the disease (thrombocytopenia, anemia etc.), it is most likely that a hematologist will be the first physician consulted. However, many believe they are unlikely to miss a diagnosis of GD as they perform bone marrow biopsy to confirm the presence of Gaucher cells. Unfortunately, false negatives are common, often because cells are located at the periphery of the smear and can be easily missed. Two thirds of GD patients already show some clinical manifestations of the disease in childhood and most will be referred to a pediatric hematologist. Unfortunately, most are not familiar with the diagnosis of GD and this may lead to unnecessary invasive procedures, such as bone marrow aspirate or/and biopsy, as well as the increase in morbidity and mortality that is seen when GD is not diagnosed and treated promptly. Using a pediatric algorithm 10, designed to promote timely diagnosis and early access to treatment, the GAU-PED study involves 53 centers across Italy. 11 Patients referred to the pediatric hematology and oncology units for spleno- and or hepatomegaly and cytopenia (thrombocytopenia and/or anemia), where other causes of splenomegaly have been excluded, were tested for GCase activity though a DBS sample. Only patients with DBS showing a GCase activity below normal values were recalled for further testing of enzyme deficiency using the gold standard GCase analysis in cell homogenate. A total of 29 DBS have been collected, with values less than 4.4 pmol/punch -1 /h 1 found in 11 patients. The diagnosis of GD has been confirmed in 4 patients (2 male and 2 female) after molecular analysis, with 1 patient reporting negative and the remaining two yet to be tested. These preliminary results suggest a very high prevalence of GD (14%). A simple diagnostic algorithm for patients presenting with splenomegaly and/or thrombocytopenia has been proposed 3 and this was used in an observational study across 33 hematology centers in Italy to identify GD type 1 among subjects referred to Italian hematology outpatient units. A total of 196 subjects were identified based on the inclusion criteria of splenomegaly and/or thrombocytopenia and provided with a Dried Blood Spot (DBS) test to assay beta-glucosidase activity. Seven out of 196 enrolled patients returned a positive DBS, three of whom were confirmed with GD after molecular analysis. Of the 27 subjects with borderline DBS tests, a further 4 were confirmed as having GD by molecular analysis. These results suggest a prevalence of GD in this high-risk cohort of 4.11%. 9 Among them, 4 patients (2 females and 2 males) had only splenomegaly, whereas in 3 patients (all females) both splenomegaly and thrombocytopenia were detected. The study was extended at the request of several centers and, as of March 2016, a further three GD patients have been identified. A pediatric study using the same protocol has also been initiated and there are plans for a further study focusing on internists rather than hematologists. These results demonstrate an appropriate diagnostic algorithm is a valuable tool to increase the recognition of a rare disease even for not disease-expert physicians. Although some precautions should be taken when using DBS for diagnosing GD, the study showed the utility of the screening test for the early diagnosis of GD. After the conclusion of the study protocol period, the number of patients referred for GD testing from hematology units is significantly increased and new cases have been diagnosed. The mean age at diagnosis was 6.7 years (min 2 - max 13). The mean time from the initial clinical presentation and diagnosis has been 19 months (min 6 - max 50), while the mean time between the DBS test and the diagnosis has been 2 months. The preliminary results support the use of as screening test for GD in a selected population of children with splenomegaly and/or thrombocytopenia considered at increased risk for the disease. The use of an appropriate diagnostic algorithm is useful to increase awareness of GD among pediatric hematologists and to shorten the time to diagnosis. Considering the long-life expectancy of pediatric GD patients, such early diagnosis can only impact positively on their health and quality of life

10 Working Group 1. Neurological aspects of Gaucher disease Working Group 1. Neurological aspects of Gaucher disease Chairs: Professor Timothy Cox, UK & Dr Allan Lund, Denmark Speakers: Professor Alessio Di Fonzo, Italy & Dr Judith Peterschmitt, US Gaucher and Parkinsonism: prevalence, mutations and counselling Dr Allan Lund, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark The association between Gaucher disease and Parkinson s was first reported in 1996 in the Israeli Gaucher population 2 and since then there have been many other studies that support the findings. 3,4 It is now clear that GBA mutations are the most important susceptibility factor for the development of Parkinson s. Naturally this association has caused anxiety in patients with Gaucher disease and their relatives, as evidence suggests they are at increased risk of developing Parkinson s disease too. Overall, the life time risk of a Gaucher patient developing Parkisnon s is fold higher than the general population with prevalence rates in the studies ranging from 2 40%. Men appear to be at slightly higher risk and older age remains a significant factor with prevalence rising as patients age. 4-8 For those who carry GBA mutations, e.g. the parents to a patient with Gaucher, the risk of Parkisnon s disease is very similar with studies suggesting a prevalence of between 2 and 15%, but there is evidence the disease will have an earlier onset of between 2 and 6 years. 9 The GBA mutations seen in Parkison s are dominated by N370S and L444P, but there are many others. There appears to be a gene-dose effect with those with two mutations having a higher level of burden of motor/ cognitive impairment, olfactory scores and hallucinations than those with one mutation, although further studies will be needed to confirm this link. 10 How should physicians counsel Gaucher patients and their families about the increased risk of Parkinson s? A through family and clinical history is the first step, focused on any neurological complaints that may have been seen. The clinical signs of Parkinson s should be explained, along with the potential treatment options and inheritance patterns. When it comes to discussing the absolute risk, it should be made clear that more than 90% of Gaucher patients will never develop Parkinson s disease, but that it is a complex disorder with various GBA mutations acting together with other causal factors. 11 Given the frequency rates seen in the general population and in those with Gaucher disease, the risk of Parkinson s in Gaucher patients, or those who carry the disease mutations, can be estimated to be approximately 6.5% Clinical signs and diagnostic approach to Parkinsonism in patients with Gaucher disease Professor Alessio di Fonzo, Policlinico Hospital of Milan, Italy Planned and ongoing early clinical studies in Gaucher-Parkinson s disease Dr. Judith Peterschmitt, Sanofi Genzyme, Cambridge, USA Neurological involvement in Gaucher disease is well described. Patients with Gaucher disease Type 2 will often show seizures, spasticity and a poor ability to suck and swallow and those with type 3 may start to show myoclonic epilepsy, ocular motor apraxia and poor coordination as the disease becomes apparent. Recently it has been discovered that patients with type 1 GD may also have neurological involvement, in particular an increased risk for Parkinson s disease from the age of 35 years. 1 Parkinson s disease is the second most common neurodegenerative disorder after Alzheimer s disease with 1% of the population affected after 60 years and 4% after 80 years. It is generally sporadic but approximately 15% of cases are familial and 5% show a clear Mendelian traits. GBA mutations are the most frequent risk factor for Parkinson s, with at least one GBA mutation found in approximately 10% of PD patients Parkinson s disease is due to the loss of dopaminergic neurons and the accumulation of alpha-synuclein leading to the three cardinal features resting tremor, bradykinesia and rigidity. The presence of two of these signs (and a response to levodopa treatment) allows for a clinical diagnosis. However, a patient may suffer from prodromal symptoms for up to 20 years before the diagnosis of Parkinson s becomes apparent. A reduced sense of smell, micrographia, constipation, Rapid Eye Movement and behavior disorder may all be present and should trigger further investigations. A neurological examination and neuropsychological tests should be done, and SPECT analysis of dopaminergic neurons in the striatum can help confirm the diagnosis. Parkinson s disease is progressive; worsening of motor functions, dyskinesias or akinesias and cognitive impairment will be seen as the disease progresses, so early diagnosis is important. There are effective pharmacological treatments to control both motor and non-motor symptoms and patients can be offered physical therapy and psychological support, all of which will improve their quality of life. Venglustat (GZ/SAR402671) is a novel glucosylceramide synthase inhibitor which is being investigated as a potential disease-modifying therapy for Parkinson s disease carrying a glucocerebroside gene mutation (GBA-PD) The MOVES-PD trial (NCT ), which has recently been started, is a phase 2 study to assess drug dynamics, efficacy and safety of venglustat in GBA-PD. The clinical trial will be split in 2 parts: a dose escalation study followed by an efficacy and safety study. Both parts will be randomized, double-blind, placebo-controlled studies at more than 50 sites worldwide. The study will enrol approximately 250 patients with early stage Parkinson s disease and who carry a GBA mutation who will be given venglustat 4, 8, and 15mg administered orally once daily using a sequential cohort design. Endpoints in part 1 will include drug safety and tolerability as well as the pharmacokinetic (PK) profile of the drug in plasma and cerebrospinal fluid and the second part will examine the changes in MDS-Unified PD Rating Scale (UPDRS) and the Parkinson s cognitive rating scale over a period of 52 weeks, with further long term follow up visits planned out to 162 weeks. Parkinson s disease is the second most common neurodegenerative disorder in the world GBA mutations are an important risk factor for Parkinson s disease at least one GBA mutation is found in approximately 10% of Parkinson s disease patients The life time risk of a Gaucher disease patient developing Parkinson s disease is fold higher than the general population Physicians should discuss the increased risk of Parkinson s disease to their Gaucher disease patients, but also reassure them that the overall absolute risk is low Research into the association between Gaucher disease and Parkinson s disease is ongoing the MOVES-PD trial is assessing the efficacy and safety of venglustat in Parkinson s patients who carry a glucocerebroside gene mutation

11 Working Group 2. Malignancy in Gaucher disease Working Group 2. Malignancy in Gaucher disease Chairs: Professor Neal Weinreb, US & Dr Derralynn Hughes, UK Speakers: Professor Madhav Dhodapkar, US & Professor Stephan vom Dahl, Germany New insights into host response to Lysolipids and Monoclonal Gammopathies Professor Madhav Dhodapkar, Yale University, New Haven, USA Cancer cells spend the majority of their life as premalignant lesions rather than a real malignancy. 7 One of the greatest puzzles in cancer biology is why do only some of these premalignancies develop into cancerous cells and how can the process be interrupted. To do this the identity of the antigenic triggers needs to be clear, reagents to identify antigen-specific immune cells are need and in vivo models are needed to test the hypothesis. Approximately 75% of patients with GD have lipidreactive immunoglobulins suggesting they play a role in a significant proportion of GD gammopathies so will targeting the antigen prevent disease? 8 In GD mice, the addition of substrate reduction therapy to their diet led to a reduction in anti-lipid antibodies and lipid-reactive clonal immunoglobulin, which other groups have confirmed reduces the number of gammopathies. 8,9 However, these findings have not yet been replicated in human studies. A first step would be to grow human pre-neoplastic gammopathies in vivo but the lack of cross-reactivity of murine cytokines prevents the engraftment of specific types of human malignant hematopoietic cells. Humanising murine models may be a way to overcome these problems and the MISTRG6 mouse seems to have a better capacity for the growth, in the same environment, of primary myeloma cells and the precursor cells than traditional models. 10 This model, and others in development, are providing new insights into disease biology including showing the clonal stability observed in patients may at least in part be dependent on tumor-extrinsic events and that the high-risk minor (but functional) subclones that often typify recurrent disease can be detected at baseline even in premalignant states. Gaucher disease and malignancy Professor Neil Weinreb, University of Miami Miller School of Medicine, USA Liver manifestations of Gaucher disease Professor Stephan vom Dahl, University Hospital Düsseldorf, Germany Multiple case studies describing malignancies in patients with Gaucher disease (GD) have appeared in the literature since the 1960s. The first population-based study was published in 2005 when the prevalence of malignancies in 2,742 GD patients in the ICGG Registry was reported. There was a higher than expected incidence of some cancers, particularly multiple myeloma and hematologic cancers such as acute myeloid leukemia and non-hodgkin lymphoma. The prevalence of some common solid tumor cancers such as lung cancer was less than expected. However, as a registry study the data were not systematically collected and many cases may have gone unreported. 1 Later studies in smaller single center European and USA GD patient cohorts followed for up to 20 years have confirmed that patients with GD have as much as a 50-fold risk for developing MGUS and myeloma and a significantly increased risk for other B-cell malignancies, myelodysplasia, myeloid leukemia and hepatocellular carcinoma. These studies also suggest perhaps a 2-fold increased risk for other malignancies as well as risk multiple cancers but this requires further evaluation. 2-4 As genomic analysis becomes more widespread and economical, purported associations between GD and malignancies in dually affected individuals will require scrutiny for coexistence of other cancer-promoting germline and somatic mutations that may either act independently or potentially be modulated by or themselves modulate GD pathophysiology. 5 Although GBA1 mutations are not oncogenic per se, the abnormal lipid biochemistry characteristic of GD promotes complement activation and aberrant innate immune cell dysregulation and dysfunction, which in turn can abet emergence and proliferation of malignant clones in specifically susceptible organs. As these pathways and mechanisms are further defined, opportunities should arise to develop preventative and targeted interventions. The effect of GD mutations on the function of macrophage sub-populations such as those specifically associated with tumor growth and metastasis (TAMs) is another fertile area for future investigation. 6 There is an increased chance of hepatocellular carcinoma (HCC) in Gaucher disease patients so awareness from treating physicians is extremely important. 2 HCC can occur without pre-existing cirrhosis and splenectomized patients are at a significantly higher risk. Good management should include a high-end ultrasound, sometimes with contrast dye, at least annually, but preferably every six months. Alphafetoprotein (AFP) is a protein made by the liver and yolk sac of the developing fetus and normally found in fetal blood. In healthy adults, AFP is present in extremely low levels. Normal adult values are low, but one half of liver cancers produce AFP so regular testing in GD patients is recommended. Transient elastography to quantify live fibrosis should also be performed regularly and those patients with elevated values (FS 7 kpa) need to be supervised more closely. Malignancy was first associated with Gaucher disease in the 1960s Data from the ICGG Registry showed an increased incidence of multiple myeloma and hematologic cancers - Some evidence of protective effects against some cancers has also seen although these findings remain unconfirmed GBA1 mutations are not oncogenic on their own but 75% of Gaucher disease patients have lipidreactive immunoglobulins that may promote the growth of malignancy New animal models are in development to study the pathophysiology of Gaucher disease-related malignancies Hepatocellular carcinoma is a particular concern in Gaucher disease patients, particularly in those who have undergone splenectomy Gaucher disease physicians should be aware of the increased risks of malignancy in their patients and ensure pre-screening programs are adhered to 18 19

12 Working Group 3. Optimal management of children with Gaucher disease Working Group 3. Optimal management of children with Gaucher disease Chairs: Professor Paige Kaplan (US), Professor Anna Tylki-Szymañska, Poland Speakers: Professor Magy Abdelwahab, Egypt misdiagnosis of ADHD or other psychiatric disorders. Outside of the classic organomegaly, bicytopenia and bone involvement, the cohort also showed pulmonary complications (recurrent infection, chronic cough, wheezing). After controlling the acute episode, these symptoms can be controlled by prophylactic antibiotic and bronchodilator therapy if severe and/or recurrent. Other non-neurological complications included lymphadenopathy (commonly involving mesenteric and mediastinal lymph nodes), eye complications (infiltrates of the cornea, vitreous and retina) that caused visual impairments in some patients, dental (infiltration of the pulps with Gaucher cells), cardiac (valve lesions, coarctation of the aorta, valvular and intercardiac calcifications etc.) and kyphoscoliosis. Data collected from this cohort shows that GD3 has a very wide phenotypic spectrum both neurological and non-neurological and uncommon presentations of GD3 should be looked for. Regular follow up of patients is important, even if they are only mildly affected, to avoid the patient suffering unnecessary adverse events. Monitoring what and when Professor Anna Tylki-Szymańska, Children s Memorial Health Institute, Warsaw, Poland Genotype phenotype correlation in children beyond N370S Professor Magy Abdelwahab, Cairo University Pediatric Hospital, Egypt Although three phenotypes of Gaucher disease have been described based on the presence or absence of neurological manifestations, the imprecise demarcation between them means it is more accurate to consider such phenotypes as a continuum of the disease. Homozygosity for L444P is most likely associated with neuronopathic Gaucher disease (GD3) with a very wide phenotypic spectrum across the world. 1 What are the most common neurological and nonneurological manifestations of neuronopathic Gaucher disease and how can you manage them? Data from an Egyptian cohort of GD3 patients showed they generally present in infancy with mild psychomotor delay, organomegaly and occasionally mild bulbar symptoms, but others may have severe visceral and hematological manifestations. Other neurological manifestations of GD 3 patients include oculomotor apraxia, squint and a variable cognitive profile, with a mean IQ ranging from There were three unique findings in this cohort of patients seizures, sudden unexplained death of epilepsy and behavioral abnormalities. Seizures were seen in 33% of patients and usually were not myoclonic in nature. Fourteen of the cohort died unexpectedly, nine of whom died after a seizure of only a few seconds and with no history of EEG abnormalities. Similar deaths have recently also been reported in a UK cohort. Behavioral abnormalities seen were mainly irritability, antisocial behavior, anger and physical/verbal aggression and there is a danger these symptoms may lead to a When presented with a potential Gaucher disease patient, what should be your strategy for diagnosing, monitoring and setting therapeutic goals? Diagnosis may come about from either newborn screening programs, where patients are still pre-symptomatic, or through a patient presenting later in life with classic symptoms. Diagnosis remains focused on the measurement of enzyme activity in leucocytes and fibroblasts, either through the use of the dried blood spot (DBS) test or measurement of biomarkers such as Lyso-GL1 and chitotriosidase. However enzyme activity is measured in vitro, it will not reflect the severity of the disease and to understand an individual patient s clinical outcome, genotyping remains the gold standard. Once diagnosed pre-symptomatic patients should be monitored at least annually, but preferably every six months. Standard checks should be made on clinical status (growth, body mass etc.), visceral volume, hematological parameters and biomarker status. For patients with neuronopathic GD a neurological consultation, IQ testing, ECG and ophthalmologic consultations should also be done. Ideally, the patient should remain under the care of the same physician to ensure continuity of care. Defining the therapeutic goals for each patient requires two components a quantitative goal and an expected time frame to achieve that goal. Such goals should be set for each component of the disease (anemia, thrombocytopenia, bone disease etc.). It is sometimes more difficult to define therapeutic goals for children due to the intense dynamics of development and therefore should be individually determined. Biomarkers such as chitotriosidase have always played an important role in the diagnosis and monitoring of patients with Gaucher disease, and the development of new biomarkers such as Lyso-GL1 that offer more sensitivity and specificity, promises to increase their role further

13 Working Group 3. Optimal management of children with Gaucher disease Working Group 4. Challenging clinical cases in Gaucher disease Family testing/diagnosis and neonatal screening Professor Paige Kaplan, University of Pennsylvania, Philadelphia, USA Chairs: Dr Nadia Belmatoug, France & Professor Claus Niederau, Germany Speaker: Professor Elena Lukina, Russia Traditionally, newborn screening (NBS) has been performed if intervention prior to clinical signs and symptoms can improve outcomes. More recently other benefits have become apparent including genetic counselling on the recurrence risk for siblings or prenatal diagnosis. It can also help identify any other undiagnosed family members who may have the disease, helping to reduce the consequences a delayed diagnosis can bring. Why should there be newborn screening for Gaucher disease? In children with Gaucher disease, in general, the diagnosis is delayed for many years after symptoms first appear. Although it is more prevalent in Ashkenazi Jews, Gaucher disease affects people of all ethnicities and race, so the majority of children with Gaucher disease are not Ashkenazi Jews. product is approved for GD type 2 or management of neurological manifestations in GD type 3. The efficacy of stem cell transplant for neuropathic Gaucher disease is not known. For those with a Type I genotype treatment can be delayed until there are physical signs and symptoms, such as a slowing in growth, bone pain, decreased blood count or increasing biomarkers. NBS has many positives as it can prevent unnecessary invasive diagnostic tests and potential morbidity as well as allow the child s family access to genetic counselling and prenatal testing for future children, should they want it. However, being presented with a diagnosis so soon after the birth of their child can lead to anxiety for the family and good physician-patient communication are needed to alleviate these worries. Protocols for NBS 4-7 suggest that once an infant has received a positive screening result they should be evaluated as soon as possible at a metabolic center to confirm the potential diagnosis by enzyme assay and genotype sequencing. If the enzyme assay is normal and only one mutation is present then it is possible the infant is a carrier and the family should be counselled over its impact and the child asked to return for follow up in late adolescence for genetic counselling. The presence of two mutations and deficient enzyme is evidence to confirm the infant has Gaucher disease; the genotype determines the type of Gaucher disease. Children at risk of developing Type 1 manifestations should be monitored every six months, and ERT can be considered if symptoms appear or worsen. Each child should be checked for fatigue, bone pain (which is often overlooked as Growing pains ), height and weight (as growth retardation is often one of the initial symptoms) and an abdominal examination. Annually the patients should have a full blood count and biomarkers such as chitotriosidase and lyso GL1 assessed for any changes. Abdominal ultrasound and MRI scans are appropriate if there are severe symptoms, biomarkers or a significant increase in spleen size by palpation. DEXA scans are usually performed every one or two years once the child has reached the age for which there are normal data. Prompt management of infants with type II/III genotypes is important- usually the two subtypes cannot be distinguised in early infancy. No ERT Diagnosis of Gaucher disease is often focused on the measurement of enzyme activity in leucocytes and fibroblasts, although genotyping remains the gold standard Once diagnosed, pre-symptomatic patients should be monitored every six months - Monitoring should include clinical status, visceral volume, hematological parameters and biomarker status Neuronopathic Gaucher disease presents across a wide phenotypic spectrum and regular follow up of patients is important - A neurological consultation, IQ testing, ECG and ophthalmologic consultations should be done Ideally, Gaucher disease patients should remain under the care of the same physician to ensure continuity of care Newborn screening is indicated if intervention prior to clinical signs and symptoms can improve outcomes, and can provide the opportunity to identify other family members with the disease - Those at risk of developing Type 1 manifestations should be monitored every six months and ERT considered if symptoms appear Whatever the approach to diagnosis and monitoring, good communication between the physician (and their wider team) and the patient (and their family) is vital to ensure the best outcomes for the patient Dr Nadia Belmatoug, Professor Claus Niederau and Professor Elena Lukina discussed a range of challenging cases across a wide spectrum of clinical situations. Case 1 discussion (Elena Lukina) Professor Lukina s first case was a 58-year-old woman with Gaucher disease Type 1 who responded well to two years of enzyme replacement therapy (ERT) but then deteriorated, presenting with weakness, fatigue, weight loss and a progressive enlargement of the spleen. Upon examination it became clear that symptoms were not Gaucher disease related, but rather manifestations of chronic myeloid leukemia (CML). Her ERT dose was reduced from 30 U/kg/every two weeks to 12 U/kg/ every two weeks and tyrosine kinase inhibitor (TKI ) therapy initiated (imatinib 400mg/day). Treatment The audience were asked questions at every stage of the diagnostic journey to help reinforce key information from the cases. placed the CML into molecular remission and there was no further sign of Gaucher disease worsening. Worsening symptoms is not necessarily directly related to Gaucher disease Regular testing for malignancies in Gaucher disease patients is universally recommended given the evidence of an increased risk 22 23

14 Working Group 4. Challenging clinical cases in Gaucher disease Working Group 4. Challenging clinical cases in Gaucher disease Case 2 discussion (Elena Lukina) Case 6 discussion (Claus Niederau) Prof Lukina s second case was a 28-year-old splenectomized man who presented with pathological femoral neck fracture and hepatomegaly. The patient was started on ERT and underwent a total hip replacement, which did not heal properly. The patient deteriorated further and developed fistulas on the buttocks. Further testing revealed he had bilateral tuberculosis sacroiliitis. The hip replacement was removed and replaced following TB and adjusted ERT treatment and the patient is now doing well. Case 3 discussion (Claus Niederau) Unclear deterioration of the clinical condition in Gaucher patients receiving ERT is an indication for additional diagnostic processes, including examination for tuberculosis Bone fragility and osteonecrosis are known factors in patients with Gaucher disease and it may be appropriate to alter ERT treatment in order to stabilize the patient before surgery. Dr Niederau s final case was a 48-year old splenectomized woman with Gaucher disease type 1 who had a good visceral and bone response to ERT but developed significant weight gain and dyspnea on exertion. Lung X-ray and CT scans were normal, as was her ECG, but after a right heart catheterization she was diagnosed with mild pulmonary hypertension. Her ERT dose was increased, she was instructed to lose some weight and is now doing well. Weight gain is normal in ERT-treated patients - Energy consumption is reduced while energy uptake is unchanged - Meal size may increase due to reduction in hepato-splenomegaly - Patients feel better after starting therapy and have more enjoyment of a good meal The risk of pulmonary hypertension is high in splenectomized women with Gaucher disease Increasing the dose of ERT in these patients may be necessary as a higher dose is needed to ensure the enzyme reaches the lung tissue Dr Niederau s first case was a 36-year old woman recently diagnosed with Gaucher disease type 1 and about to begin ERT. A tumor was discovered between the kidney and spleen and a fine-needle biopsy showed only Gaucher cells without any other parenchymal cells. This suggested a Gaucheroma rather than malignancy. The patient was started on ERT (60 U/kg/every 2 weeks and responded well. The Gaucheroma has decreased in size over the course of ERT. Case 4 discussion (Claus Niederau) Dr Niederau s second case was a 51-year old woman with Gaucher disease type 1 who responded well to ERT but who later developed bone pain. An increase in the dose of ERT did not ameliorate the problem and a biopsy discovered a B-cell lymphoma. Appropriate treatment was started and the patient is now doing well. Case 5 discussion (Claus Niederau) Dr Niederau s third case was a 51- year old woman with Gaucher disease type 1 who had started ERT in In 2007 she presented with increase fatigue as well as noncharacteristic muscle and bone pain. The patient s symptoms were unfortunately caused by liver metastases of bilateral breast cancer and she died soon afterwards. Previously she had refused premalignancy screenings. Gaucheromas can be mistaken for other more serious and potentially life-threatening conditions and they need immediate investigation Needle biopsies are effective in distinguishing Gaucheromas from malignancies, but should not be done in patients with bone infarcts or other crises as they can introduce bacteria to the site The relative risk of multiple myeloma increases by between 6 and 50 times in patients with Gaucher disease It is important to consider myelomas when new or worsening symptoms appear Given the evidence for increased malignancies in Gaucher disease patients, the importance of screening programs should be made abundantly clear to patients Case 7 discussion (Nadia Belmatoug) Dr Belmatoug s first case was a 22-year old Algerian woman presenting with menometrorrhagia, and history of hepatosplenomegaly, transfusion, hearing loss and strabismus. Unfortunately, the patient did not speak French and the clinical history taken missed several important facts such as past learning and attention difficulties and memory disorders. Eventually a molecular analysis revealed a homozygous D409H genotype and a diagnosis of Gaucher disease type 3c was made. Case 8 discussion (Nadia Belmatoug) Dr Belmatoug s final patient was a 60-year-old man with Gaucher disease who had been treated with ERT through a venous central catheter since He developed acute intermittent fever and painful cervical adenopathies and was eventually hospitalized. Bacterial cultures were taken and showed a Propionobacterium acnes infection related to the catheter. The patient was successfully treated with antibiotics and was switched to oral substrate reduction therapy despite the presence of cardiac risk factors that need close monitoring. A complete examination of the patient, including genotyping, is crucial A better understanding of the pathophysiology and prognosis in Gaucher disease type 3c patients is necessary Take home message: Always investigate patients who have been stable on treatment but who develop new symptoms or an unexpected recurrence of old symptoms 24 25

15 Plenary Session 3: Substrate Reduction Therapy Plenary Session 3: Substrate Reduction Therapy Chair: Professor Hans Aerts, University of Leiden, The Netherlands Substrate Reduction Therapy: Real world Experience Professor Pramod Mistry, Yale University School of Medicine, New Haven, US Enzyme Replacement (ERT) and Substrate Reduction Therapies (SRT) have unique, independent and in theory complementary mechanisms of action, and the availability of eliglustat has increased therapeutic options for the effective clinical management of type 1 Gaucher disease. Eliglustat is a glucosylceramide analogue acting as an inhibitor of glucosylceramide synthase and pharmacological studies indicated a high therapeutic index and good oral bioavailability. To date there have been over 1400 patient-years of eliglustat exposure and it has generally been well tolerated and effective as both monotherapy in de novo treated patients and as a maintenance therapy after stable patients were switched from ERT. 1 When deciding on treatment physicians should consider all available therapeutic options and take time to explain carefully the pros and cons of both ERT and SRT to the patient. The potential for non-compliance must always be assessed but many patients, especially those of younger age or who travel frequently, do appreciate the convenience of an oral formulation. Therapeutic goals should be agreed and are likely to be similar to those for ERT a reduction of hepatosplenomegaly, improvements in cytopenia and a decrease in bone pain. Based on the clinical trial data it is reasonable to expect bone density and bone marrow burden score to improve within 1 to 2 years of treatment. Eliglustat patient monitoring is similar to that required for ERT. A clinic appointment at three months should check compliance, monitor biomarker changes and ask the patient about any side effects. A further follow up at 6 months followed by regular annual clinic assessments should then be sufficient to identify clinical progress and any potential problems. The Yale Cohort of eliglustat patients has experienced the effectiveness of this monitoring regimen, as well as the overall efficacy of treatment. 2 Of the 44 patients on treatment, 8 have been on eliglustat longer than five years and 13 longer than two years. Gaucher disease patients are often highly motivated and this has been seen in very high (>95%) compliance rates. Few patients have suffered significant adverse events and only two have switched back to ERT after complaining of fatigue. Visceral and hematologic responses have been similar to those seen in the clinical trial program and long-term responses have been maintained. For patients starting treatment with eliglustat it is incumbent on the physician to carefully explain the mechanism of action in a form they can understand to help allay any fears patients may have over the potential for side effects and drug interactions. The latter is a natural concern of older patients, as they may be on multiple concomitant medications for other diseases, but clinical experience suggests eliglustat remains well tolerated across the adult-aged population. To date the real-world experience of eliglustat has matched that seen in the clinical trial program. Continuing to follow patients over the longer-term will increase our understanding of the disease as well as provide more information on how treatment affects the longer-term complications of Gaucher disease, such as avascular necrosis. Long-Term Treatment Response to Oral Eliglustat in patients with Gaucher Disease Type 1 Professor Elena Lukina, National Research Center for Hematology, Moscow, Russia As part of the eliglustat clinical trial program, the largest to date in Gaucher disease, three Phase 2 and 3 trials were undertaken. The Phase 2 trial was an open-label study in 26 treatment-naïve patients 3, and the two Phase 3 trials were both randomized. ENGAGE 1 was a placebocontrolled study of 40 treatment-naïve patients and ENCORE 4 was an imiglucerase-controlled trial in 159 patients previously stabilized on 3 years of enzyme replacement therapy. Hematological and visceral improvements were seen in the phase 2 and ENGAGE studies. After four years of treatment in the Phase 2 trial platelets had increased by 95%, hemoglobin by 2.3 g/dl from baseline and liver and spleen volumes decreased by 28% and 63%, respectively. Comparable results were seen after 4.5 years in the ENGAGE where platelets increased by 87%, hemoglobin by 1.4 g/dl and reductions in liver and spleen volumes by 23% and 66%. 1,3 Hematological and visceral parameters were successfully maintained throughout the 4 year follow up period of the ENCORE trial. 4 Skeletal responses were also encouraging. In the Phase 2 trial, lumbar spine T-scores improved by 0.8 after four years, moving patients from a level consistent with osteopenia to one of normal bone density. In the ENGAGE study, bone marrow burden (which reflects the level of bone marrow infiltration of Gaucher cells) reduced significantly after four years with bone density increasing over the same time frame. In patients previously stabilized on ERT (ENCORE), bone mineral density remained stable over the four years of the trial. 1,3,4 Biomarker responses were also consistently improved. GL-1, Lyso-GL1, CCL18 and chitotriosidase all fell to around 20% of their baseline values after 4 years in the Phase 2 study with broadly comparable results in ENGAGE. In ENCORE, where previous treatment with ERT had stabilized biomarkers into a normal range, eliglustat maintained these effects for up to four years. 1,3,4 For the Phase 2 and ENGAGE trials, four therapeutic goals were defined as clinically relevant reductions in spleen and liver size and increases in hemoglobin and platelet levels. In the Phase 2 study all patients met at least 3 of these goals of these goals 4 years, 100% of patients met the therapeutic goals established for long-term ERT treatmentfor spleen volume and hemoglobin level, 94% met the goal for liver volume, and 47% met the goal for platelet count. In the ENGAGE study, among the patients with 2.5 years of data, the majority met all 4 goals, and 91% met at least 3 goals. In the ENCORE study, more than 90% of patients maintained the therapeutic goals they had achieved during pre-trial ERT treatment. 1,3,4 In all 3 trials, eliglustat was generally well tolerated. Only 21 patients across the three trials withdrew nine due to adverse events, four to pregnancy and the remainder for unspecified reasons. Across the studies, most adverse events were mild and considered unrelated to treatment. In the Phase 2 study there was one serious adverse event that was considered possibly related to eliglustat an incidence of non-symptomatic non-sustained ventricular tachycardia that required hospitalization and in ENGAGE two events of mild atrioventricular block were reported in a single patient and considered possibly related to treatment. 1,3,4 In summary, long term eliglustat was associated with continued improvements in hematological, visceral, biomarker and bone parameters in de novo adult patients with GD1. In adult GD1 patients previously treated with ERT, eliglustat maintained therapeutic goals in more than 90% patients over 4 years. 1,3,4

16 Plenary Session 3: Substrate Reduction Therapy Plenary Session 3: Substrate Reduction Therapy Practical management of eliglustat therapy in Gaucher disease type 1 Professor Claus Niederau, Katholisches Klinikum Oberhausen, St. Josef-Hospital, Germany Practical management of eliglustat therapy in Gaucher disease includes aspects of patient selection, CYP2D6 genotyping, monitoring of effects, safety and adherence, and observing potential drug-drug-interactions. 5,6 Eliglustat is indicated for the treatment of adult patients with Gaucher disease type 1 who are poor, intermediate or extensive metabolizers 5 ; it is not approved for use in Gaucher disease type 2 or type 3. In routine clinical practice, it is difficult to measure serum trough levels of eliglustat, which was the basis of dosing in the clinical trial program, so prospective patients should be genotyped for CYP2D6 to determine their metabolizer status. Intermediate Metabolizers (IM) and Extensive Metabolizers (EM) receive 84 mg eliglustat twice daily while Poor Metabolizers (PM) receive 84 mg eliglustat once daily. Eliglustat should not be given in Ultrarapid Metabolizers (URM) nor in patients in whom the metabolizer type cannot be determined. Although over 90% of patients in the clinical trial program were IM or EM, but there will be certain geographical regions (such as North Africa or Arabia) where the percentage of URM may be much higher. Eliglustat is metabolized by the cytochrome P450 enzymes CYP2D6 and CYP3A and therefore has the potential to interact with several commonly co-prescribed medications. 5 Co-administration of eliglustat with CYP3A inducers may significantly decrease eliglustat exposure, and thus the use of eliglustat with strong CYP3A inducers (e.g. rifampicin, carbamazepine, phenobarbital, phenytoin, rifabutin and St. John s wort) is not recommended. 5 In contrast, drugs that inhibit CYP2D6 and CYP3A pathways may significantly increase the exposure to eliglustat. Thus, some inhibitors of CYP2D6 and CYP3A are contraindicated with eliglustat or may require dosage adjustment of eliglustat depending on the patient s CYP2D6 metabolizer status (see full prescribing information for details) 5. Eliglustat is contraindicated and/ or may need to be used with caution in patients who are CYP2D6 intermediate metabolizers (IMs) or extensive metabolizers (EMs) taking a strong (e.g. paroxetine, fluoxetine, quinidine) or moderate (e.g. duloxetine, terbinafine) CYP2D6 inhibitor concomitantly with a strong (e.g. clarithromycin, itraconazole) or moderate (e.g. erythromycin, fluconazole) CYP3A inhibitor, and in patients who are CYP2D6 poor metabolizers (PMs) taking a strong CYP3A inhibitor. Dose reduction or caution should also be taken with a single concomitant CYP450 inhibitors with a variety of commonly co-prescribed medications, such as anti-depressants, fungal treatments and antibiotics (see full prescribing information for details). Grapefruit products contain one or more components that inhibit CYP3A and can increase plasma concentrations of eliglustat. Consumption of grapefruit or its juice should be avoided. 5 Since eliglustat is also an inhibitor of P-gp and CYP2D6, co-administration of eliglustat with drugs that are substrates for P-gp or CYP2D6 may result in increased concentrations of the concomitant drug. In the latter case, it is advized to monitor the concentration of the concomitant drug or to consider to reduce the dosage of the concomitant drug and to titrate it to its clinical effect. Caution is necessary in particular for co-medications that have a small therapeutic window such as digoxin or dabigatran (see full prescribing information for details). 5 Because eliglustat is predicted to cause mild increases in ECG intervals at substantially elevated plasma concentrations, its use should be avoided in patients with cardiac disease (congestive heart failure, recent acute myocardial infarction, bradycardia, heart block, ventricular arrhythmia), long QT syndrome, and in combination with Class IA (e.g. quinidine) and Class III (e.g. amiodarone, sotalol) antiarrhythmic medicinal products. 5 Prior to starting eliglustat, it should be checked whether the patient is pregnant or plans to become so, as eliglustat should be avoided during pregnancy. 5 Practical experience in fifty adult German patients with type 1 Gaucher disease shows that thirteen patients are taking eliglustat, all of whom were genotyped for CYP2D6 prior to therapy and found to be IMs and EMs. Substrate Reduction Therapy Treatment Guidelines Dr Nadia Belmatoug, Beaujon Hospital, Clichy, France Two treatment guideline papers have been published, one in the EU and one in the USA. 6,7 The EU report brought together 14 experts from across the continent, featuring a multidisciplinary group including a cardiologist specialising in cardiac arrhythmias. The aim of the group was to help physicians prescribe eliglustat appropriately by providing simple, clear and practical guidelines. Eliglustat was approved in the USA in August 2014 and in Europe five months later for use in the long-term treatment of adult patients with Gaucher disease type 1, who are CYP2D6 PMs, IMs or EMs. It can be used as a first-line therapy in treatment-naïve patients and for patients who are stable on ERT and wish to transition to an oral maintenance therapy. Genotyping is mandatory prior to treatment as it should not be used in ultrarapid metabolizers or those who are indeterminate metabolizers. The metabolism of eliglustat is strongly dependent on CYP2D6 and (to a lesser extent) CYP3A of the cytochrome P450 pathway, which means that drug interactions and CYP2D6 metabolizer status are significant determinants for drug eligibility and dosing. These potential interactions mean eliglustat is contraindicated with drug combinations of strong/ moderate CYP2D6 and CYP3A4 inhibitors (IMs and EMs) and with strong CYP3A4 inhibitors (PMs). Eliglustat has not been studied in patients with renal or hepatic impairment and therefore no dose recommendations can be made. At 11-fold higher than usual therapeutic concentrations, eliglustat is predicted to cause mild Patients taking eliglustat were significantly younger than those still on ERT mostly because they had a lower rate of comorbidity and co-medication. Eliglustat adherence was as yet not a significant issue, but should be checked regularly with clinical and laboratory responses the most effective way of revealing any problems. As a first-line or switch therapy for eligible adults with Gaucher disease type 1, eliglustat offers patients a convenient, effective and well tolerated oral therapy, but physicians should carefully assess each patient to determine their appropriateness and continue to monitor their response to treatment and any change in concomitant medications to ensure the best outcome. 6 increases in QTc, PR and QRS intervals and eliglustat is not recommended in patients with pre-existing cardiac disease such as congestive heart failure, bradycardia, long QT syndrome on in combination with certain anti-arrhythmia medications. 5-7 For patients taking a short course of a potentially QT-prolonging drug, such as cold or flu medicine, the physician should consider temporarily discontinuing eliglustat until the course is finished. 6,7 Results from eliglustat studies in post-kidney transplantation or in patients with hepatic impairment are not yet available, so no dose recommendations 28 29

17 Plenary Session 3: Substrate Reduction Therapy can be made. Nor have there been any adequate, well controlled studies during pregnancy or lactation and therefore eliglustat should be avoided at these times. 5-7 Patients who are switching from ERT to eliglustat should be thoroughly assessed before treatment starts for concurrent illness, concomitant medications, likelihood of adherence and pregnancy. In these circumstances, physicians should undertake a rigorous clinical and biological evaluation of the patient s disease to provide baseline readings before the switch. Eliglustat should be started within two weeks of the final ERT infusion and the patient monitored for efficacy and any emergence of adverse events. 6,7 Given the potential for drug-drug interactions, patients should be advized to inform any other treating physician about their eliglustat use, and reminded to consult their physician before using any over the counter medications or herbal supplements. 6,7 Eliglustat is an effective and well tolerated treatment, but requires a thorough evaluation of the patient prior to, and regular monitoring during, treatment. 6,7 The faculty of the 7 th Gaucher Leadership Forum 30 31