Oral maintenance clinical trial with miglustat for type I Gaucher disease: switch from or combination with intravenous enzyme replacement.

Enzyme replacement therapy (ERT) with imiglucerase reduces hepatosplenomegaly and improves hematologic parameters in Gaucher disease type 1 within 6-24 months. Miglustat reduces organomegaly, improves hematologic parameters, and reverses bone marrow infiltration. This trial evaluates miglustat in patients clinically stable on ERT. Tolerability of miglustat and imiglucerase, alone and in combination, pharmacokinetic profile, organ reduction, and chitotriosidase activity were assessed. Thirty-six patients stable on imiglucerase were randomized into this phase II, open-label trial. Statistically significant changes from baseline were assessed (paired t test) on primary objectives with secondary analyses on biochemical and safety parameters. Liver and spleen volume were unchanged in switched patients. No significant differences were seen between groups regarding mean change in hemoglobin. Mean change in platelet counts was only significant between miglustat and imiglucerase groups (P = .035). Chitotriosidase activity remained stable. In trial extension, clinical endpoints were generally maintained. Miglustat was well tolerated alone or in combination. Miglustat's safety profile was consistent with previous trials; moreover, no new cases of peripheral neuropathy were observed. Gaucher disease type 1 (GD1) parameters were stable in most switched patients. Combination therapy did not show benefit. Findings suggest miglustat could be an effective maintenance therapy in stabilized patients with GD1.

Uveitis in Gaucher disease.

PURPOSE: Chronic uveitis has been previously reported in a patient with Gaucher's disease and improved with enzyme replacement therapy. This report describes the course of uveitis in two other patients with type I Gaucher's disease. DESIGN: Observational case reports. METHODS: Review of all patients in a large referral clinic for Gaucher's disease for incidence of uveitis. RESULTS: Two patients with uveitis among 527 patients (0.4%) were found. Each had a different clinical outcome from the other and from the patient cited in the literature. CONCLUSIONS: Both patients have mild Gaucher's disease, but one patient has uveitis well controlled for 10 years solely by local corticosteroids, whereas the other has suffered progression of uveitis despite enzyme replacement therapy.

Bone density changes with enzyme therapy for Gaucher disease.

Gaucher disease is the most common lysosomal storage disease. Enzyme replacement therapy engenders improvement in hematological and visceral parameters; however, improvement in bone density (BMD) with treatment has not been confirmed. This study presents follow-up of BMD in the first ten patients in Israel treated with low-dose recombinant enzyme for up to 108 months. BMD at femoral neck and lumbar spine was determined by dual-energy X-ray absorptiometry (DEXA) at the start of the trial, after 3-6 months, after 18-24 months, and at the most recent follow-up. BMD in all patients was very low at onset and never normalized. There was a decrease in BMD in all patients at 3-6 months. Older patients (four women, two men; >30 years of age) showed some improvement in BMD during treatment. Younger patients (four females; 18-23 years of age) did not show a statistically significant improvement. These findings might reflect the failure of patients with Gaucher disease to achieve expected peak bone density at appropriate chronological milestones despite treatment. Nonetheless, the z-scores of the older patients were better than those of the younger patients, implying some catch-up period. Yet, some patients with Gaucher disease evince rapid onset of osteoporosis in early adulthood. Enzyme treatment per se, as well as attendant improved well-being and increased physical activity, may induce amelioration in BMD at this later stage. One may consider adding anti-osteoporosis therapy in young adults to induce earlier "catch up" to peak bone mass, and then enzyme replacement in later adulthood to prevent decrements in bone mass related to Gaucher cell infiltration.

Orthopedic considerations in Gaucher disease since the advent of enzyme replacement therapy.

Gaucher disease, the most prevalent lysosomal storage disorder, is characterized by hepatosplenomegaly, hypersplenism, and rarely, neurological involvement. The most variable symptoms relate to skeletal disease, and both onset and progression are difficult to predict on the basis of genotype. This review describes findings from a large referral clinic (> 500 patients) and from the literature in the decade since the advent of specific enzyme replacement therapy. Such therapy is effective in reducing visceral and hematological involvement, but its greatest advantage as regards the skeleton is prevention of irreversible damage. Avascular necrosis of the joints-particularly the hips but also the knees and shoulders-and pathological fractures of the long bones including the ribs, as well as episodic "crises' of bone pain in children and young adults, are common manifestations. Various imaging modalities should be performed at baseline for life-long monitoring, and then as required because of specific complaints. Surgical interventions such as joint arthroplasties are important adjuvant treatments in this population; presurgical hematological profiling plus antibiotic cover and postoperative pain control are equally critical. Opportunities for orthopedic consultations with senior surgeons are not abused by our patients. These reflect disease-related morbidity, with greater numbers of requests being made by patients requiring enzyme therapy, who by definition have more severe disease characteristics.

Type I Gaucher disease in children with and without enzyme therapy.

This retrospective study describes the course of 56 children with non-neuronopathic Gaucher disease who presented at <16 years and were followed at 6- to 12-month intervals for 3-9 years. Massive splenomegaly and height retardation marked those who required treatment. Enzyme replacement significantly increased hemoglobin levels; platelet counts were divergent at presentation and follow-up, regardless of therapy. Among treated patients there was a significant reduction in liver and spleen index volumes, and a significant increase in height z-scores. None of the children required splenectomy or developed lung involvement. Many patients diagnosed due to large-scale screening were very mildly affected and remain untreated.

Thrombocytosis associated with enzyme replacement therapy in Gaucher disease.

We describe a patient with an intact spleen and moderately severe symptoms of Gaucher disease in whom, after initiation of (low-dose) enzyme replacement therapy (ERT), thrombocytosis (720 x 10(9)/l) was documented. Checking the International Gaucher Registry database revealed that this patient is the only nonsplenectomized patient of more than 1,000 treated patients to experience ERT-induced thrombocytosis. Platelet counts dropped immediately after the discontinuation of ERT.

Gaucher disease: pediatric concerns.

Gaucher disease, the most prevalent lysosomal storage disorder, is inherited as an autosomal recessive condition. The gold standard for diagnosis is decreased acid beta-glucosidase activity in the lymphocytes or fibroblasts; molecular analysis of mutations allows for some prognostication of disease severity. Prenatal diagnosis and carrier testing for at-risk families are currently available. There is tremendous phenotypic heterogeneity in the non-neuronopathic form (type I), ranging from clinically asymptomatic to massive hepatomegaly, hypersplenism, growth retardation in children and extensive involvement of bone and lungs. Presence on one allele of the most common mutation, N370S, which is the most prevalent among Ashkenazi Jews for whom there is a predilection for Gaucher disease, is protective of neurological involvement. Some mutations, such as 84GG and IVS2+1, are associated with more severe disease manifestations when appearing as compound heterozygotes with N370S, but when occurring in the homozygous state are not compatible with life. Other mutations, such as L444P, are associated with severe non-neurological disease when occurring as compound heterozygotes with N370S, but when occurring in the homozygous state may be predictive of neurological disease of either acute (type II) or subacute (type III) forms. In the past decade, enzyme replacement therapy has become available which has resulted in a reduction in liver and spleen volume and consequently improved anemia and thrombocytopenia in most patients. It has also engendered catch-up growth in many children, induced improvement in lung involvement secondary to Gaucher disease, and to some extent ameliorated episodes of bone pain. By virtue of treatment, many children who may have been severely affected no longer need to undergo splenectomy to treat hypersplenism, and therefore they are not at risk of bone involvement consequent to the loss of the preferred reservoir for lipid-laden 'Gaucher cells'. However, enzyme treatment is ineffective in reversing neurological signs, requires a lifelong commitment to intravenous infusions, thereby reducing quality of life, and is relatively expensive for many national health schemes. Hence, alternative forms of treatment, such as substrate balance, are being explored. Symptomatic management, including orthopedic surgery, pain relief for bone pain and even splenectomy, still has importance for patients with Gaucher disease. In addition, there is the potential for bone marrow transplantation and, in the future, gene therapy to be curative, particularly for patients with the neuronopathic forms.