To determine treatment effects in the unique and previously internationally unreported Japanese paediatric patient population with Gaucher disease (GD), we analysed six response parameters among 13 patients given enzyme replacement therapy (ERT). Also to obtain insights into optimising maintenance dosing, through subgroup analysis we retrospectively examined effects of three ERT dose reduction schedules from a starting regimen of 60 U/kg of body weight every 2 weeks. Our patients included 11 males and two females, 11 individuals with possible type 1 and two individuals with type 3b GD, six individuals with the L444P/F2131 genotype and five with the L444P/L444P genotype, and five who had been splenectomised. Despite different mutation prevalence, Japanese patients with GD, like their counterparts from other ethnic groups, generally benefitted from ERT. However, early and marked ERT dose reduction (from 60 U/kg to 30 or 15 U/ kg every 2 weeks within < or =6 months) was associated with insufficient improvement of mean haemoglobin level and relative height and with insufficient improvement or worsening of platelet count. Only the subgroup given 60 U/kg of ERT every 2 weeks for 36 months had significant improvement in mean haemoglobin, platelet count, angiotensin-converting enzyme and acid phosphatase levels and relative height at 36 months.
Conclusion: These data suggest that long-term high dose enzyme replacement therapy may be required to obtain sufficient improvement to maintain health among paediatric patients with severe Gaucher disease.