Velaglucerase alfa as a therapeutic option for Gaucher disease

Gaucher disease (GD) is an inherited disorder characterized by deficiency of the lysosomal enzyme glucocerebrosidase and the accumulation of an incompletely metabolized substrate (glucocerebroside) in cells of monocyte lineage. Clinical manifestations include anemia, thrombocytopenia, hepatosplenomegaly and bone disease; in a subset of patients with the neuropathic form, additional problems related to primary CNS involvement develop, resulting in a shortened lifespan. Velaglucerase alfa is a human recombinant formulation of glucocerebrosidase; in clinical trials it has been shown to be safe and effective in reversing the cardinal systemic features of GD. Prior to the introduction of velaglucerase alfa, enzyme replacement therapy with imiglucerase for GD type 1 (the non-neuronopathic form) had been established as the standard of care. Problems with imiglucerase supply have resulted in the increased use of velaglucerase alfa, through an expanded access program prior to regulatory approval (which was obtained in February 2010 in the USA and more recently in countries of the EU). Thus far, the therapeutic profile for velaglucerase alfa appears comparable to the historical data set for imiglucerase, although the reported rate of antibody formation against velaglucerase alfa is lower (1 vs 15%). In addition, in vitrostudies involving human macrophages have demonstrated a more rapid internalization of velaglucerase alfa. The long-term implications of these observations need to be established. Moreover, factors that will influence the choice of treatment agent in GD patients will need to be determined.