Gaucher Disease |
1 Haematology Department, Miguel Servet University Hospital, Zaragoza
2 CIBER de Enfermedades Raras (CIBERER)
3 Haematology Department, Basurto, Bilbao
4 Haematology Department, Virgen del Puerto Plasencia, Plasencia
5 Haematology Department, Ntra Sra de Sonsoles Hospital, Avila
6 Haematology Department, Punta Europa University Hospital, Cádiz
7 Haematology Department, Virgen del Rocío University Hospital, Sevilla
8 Haematology Department, Virgen de la Concha Hospital, Zamora
9 Spanish Foundation for the Study and Therapy of Gaucher Disease (FEETEG)
10 Biochemistry and Molecular and Cellular Biology Department, Zaragoza University, Zaragoza
11 Aragon Institute of Health Sciences (I+CS), Zaragoza, Spain
Correspondence: Pilar Giraldo, Sº Hematología, Hospital Universitario Miguel Servet, Pº Isabel La Católica 1–3, 50006 Zaragoza, Spain., E-mail: pgiraldo{at}salud.aragon.es
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Key words: type 1 Gaucher disease, substrate reduction therapy, efficacy and safety, maintenance, real clinical setting.
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Because GD1 is a chronic and non-curable disease, maintenance of therapeutic goals, quality of life and treatment cost-effectiveness in stabilized patients are key objectives during long-term treatment.6–8 Maintenance therapy using SRT with miglustat (Zavesca®), an oral inhibitor of the ceramide-specific enzyme, glucosyltransferase,9 may represent a valuable alternative treatment option in GD1 patients who have achieved therapeutic goals on ERT. There is limited published information on real-world clinical experience with miglustat in such patients. However, clinical trial findings10–13 and data from everyday clinical practice14,15 have indicated improvements across a range of efficacy endpoints in GD1, both in treatment-naïve patients and those previously or currently treated with ERT. Moreover, miglustat was well tolerated during trial extension studies.12,13
Following regulatory approval of miglustat in Spain, the prospective ZAGAL study was designed by the Spanish Gaucher Disease (GD) Foundation according to European Working Group on GD Advisory Council recommendations, and was subsequently approved by the Ethics Committee for Clinical Investigation of Aragon (CEICA). The aim of this study, which draws on data from the National Spanish GD Registry (SGDR), was to evaluate the efficacy, safety and tolerability of miglustat in patients with mild-to-moderate GD1 being treated in the real-world clinical practice setting. We have previously reported data on the short-term efficacy of miglustat in treatment-naïve patients and those switched from previous ERT.15 Here we present long-term efficacy and safety/tolerability findings recorded during up to 48 months of miglustat treatment in patients switched from previous ERT.
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The efficacy of miglustat as a maintenance therapy was evaluated based on organ size (liver size by abdominal clinical examination and spleen length by ultrasound), hemoglobin concentration, platelet count, and plasma biomarkers (chitotriosidase [CT] and CCL18/PARC). Changes in bone marrow infiltration were quantified using the Spanish MRI Scoring system.16 Assessments were performed at six, 12, 24, 36 and 48 months.
A neurological and neurophysiological study with superficial electroneurogram in sural and peroneal nerves, as well as a Memory Impairment Screen (MIS), was applied to all patients by the same specialist. Quality of life was evaluated using the SF-36 questionnaire, with assessments performed prior to commencement of miglustat therapy and two years after.
Statistical analyses were performed using an SPSS database; comparisons between means were conducted using the non-parametric Mann–Whitney U test.
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View this table: [in a new window] [Download PPT slide] |
Table 1. General patients characteristics.
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Figure 1. Algorithm with patients distribution.
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Figure 2. Changes from baseline in standard disease parameters at 48 months.
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Our data support findings from previous clinical trials with miglustat10–14 indicating that clinical and analytical responses obtained with ERT therapy are maintained in patients switched to miglustat. Our findings should also be considered alongside previously reported data comparing miglustat with ERT in the largest clinical trial in GD1 patients to date.14 Most patients were stabilized on miglustat therapy, given alone or in combination with ERT, on all key disease parameters assessed.14 In addition, data from post-marketing clinical experience with miglustat have so far confirmed that clinically relevant therapeutic benefits can be achieved with long-term miglustat therapy, with an acceptable safety/tolerability profile.17,18
Skeletal abnormalities are a serious manifestation of disease in GD1.19 Due to physico-chemical properties that enable a wide distribution throughout body tissues, miglustat has the potential to reach effector cells within bone. A pooled analysis of the effect of miglustat on bone manifestations and on bone mineral density (BMD), using data collected prospectively over two years from GD1 patients in three multinational, open-label clinical trials with miglustat, was published in 2007. Early and sustained increases in lumbar spine and femoral neck BMD were seen after starting miglustat monotherapy, with significant increases from baseline evident at six, 12, and 24 months. No bone crises, avascular necrosis or bone fractures were reported during two years of follow-up.20
No patients in our study reported bone pain or bone crisis during 48 months of therapy. Bone marrow infiltration in the spine was reduced by a mean of 2.9 points on the S-MRI scale (range, 1–4 points) during 36 months of miglustat therapy (Table 1). While the mechanism of action of miglustat on bone manifestations has not been fully clarified, it is known to affect osteoclastogenesis,21 and to penetrate bone sufficiently to reach deep-lying effector cells.22,23 For these reasons, miglustat might be a valuable treatment option for the improvement of bone disease in patients with GD1. However, further, dedicated studies may be required to fully evaluate this.
Analysis of data from the SF-36 assessment at 24 months revealed that improvements from baseline across all items were similar in miglustat-treated patients and those receiving ERT. The quality of life scores in this patient cohort were also similar to those recorded in the general Spanish population (data not shown).
With regards to safety and tolerability, 6 out of 28 patients (21%) complained of mild gastrointestinal disturbances which resolved after changing to a low-carbohydrate diet, in line with data from long-term extension trials.12,13 Patients receiving miglustat can be susceptible to gastrointestinal disturbances due to inhibitory effects on gut disaccharidases. In our cohort, low-dietary carbohydrate intake was recommended during the first weeks of miglustat therapy, with adjustments made thereafter according to individual tolerance. We consider that the occurrence of gastrointestinal adverse events in our patient cohort was lower than expected, likely due to the low-carbohydrate diet recommendation during the first weeks of therapy.
Five patients had moderate weight loss (mean [SD] 3.8 [2.38] kg; range 1–8 kg; representing a weight loss of 1.5 to 8.3% of total body weight). Conversely, 9 patients had moderate body weight gain (mean [SD] 1.3 [1.00] kg; range 1–4 kg). Body weight was stable in the remaining patients. Eight patients experienced a mild hand tremor during the first weeks after commencing treatment, but this had no effect on manual dexterity. No peripheral neuropathy or cognitive impairment was reported. The mean (SD) MIS score was 6.3 (1.66) points among the 22 patients evaluated at baseline, 6.4 (1.49) points in the 20 patients evaluated at 12 months, 6.2 (1.52) points in the 18 patients evaluated at 24 months, and 6.0 (1.50) in the 11 patients evaluated at 36 months. The range of MIS scores across all intervals was 4–8.
Of the patients who discontinued treatment, 3 patients discontinued due to poor compliance and one discontinued due to gastrointestinal discomfort related to the study drug (patient decided to stop therapy). Three patients died of unrelated diseases; one patient died after nine months on therapy because of melanoma complications, another died after seven months on therapy because of myocardial infarction, and one died after 18 months on therapy because of complications related to genital cancer. In summary, the results of this study confirm that miglustat is effective and well tolerated in patients with mild-to-moderate GD1 treated over the long term in everyday clinical practice. Miglustat is effective in the long-term maintenance of disease stability achieved on previous ERT, and has an acceptable safety and tolerability profile, which features preventable gastrointestinal effects.
All authors are members of the SGDG, which is supported by the Spanish Gaucher Disease Foundation (FEETEG). The corresponding author and some of the other authors are researchers at the Aragon Institute of Public Health (I+CS). This study was funded by FEETEG. PA, KA, MAFG, AB, RF, DA, AM, PL report no conflicts of interest. PG and MP have received consultancy fees from Actelion Pharmaceuticals Ltd. for participation in clinical trial programs and other projects, and speaker fees for participation in scientific congresses and sponsored events. PG and MP donate all fees to the National Gaucher Foundation, which supports research in the field of lysosomal storage disorders.
The authors would like to thank all the members of the Spanish Gaucher Disease Group (SGDG) who provided clinical data and samples. The complete list of physicians of the SGDG who have contributed is available at: www.feeteg.org.
The online version of this article contains a supplementary appendix.
PG: responsible for the Spanish Registry of Gaucher Disease, conducted the study, analyzed and interpreted the data, and drafted the manuscript; PL: contributed to the statistical analysis and to the manuscript; PA: contributed to the enzymatic, genetic, serum biomarker, and statistical analyses; KA, AB, RF, DA, AM and MAF-G: collected clinical, analytical and follow-up data and contributed to analyses; MP: helped conduct the study, interpreted genetic and biochemical data, and edited the manuscript.
Received for publication March 1, 2009. Revision received May 22, 2009. Accepted for publication June 5, 2009.
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