Phase 1/2 and extension study of velaglucerase alfa replacement therapy in adults with type 1 Gaucher disease: 48-month experience.

Enzyme replacement therapy is the standard of care for symptomatic Gaucher disease. Velaglucerase alfa is a human beta-glucocerebrosidase produced in a well-characterized human cell line. A 9-month phase 1/2 open-label, single-center trial and ongoing extension study were conducted to evaluate safety and efficacy of velaglucerase alfa. Twelve symptomatic adult type 1 Gaucher patients (intact spleens) received velaglucerase alfa (60 U/kg per infusion) during phase 1/2. An extension study was offered to patients completing the trial; step-wise dose reduction (to 30 U/kg per infusion) was instituted. Eleven patients completed phase 1/2; 10 entered the extension; 9 patients reached 39 months of extension. No drug-related serious adverse events or withdrawals, and no antibodies were observed. Home therapy was successfully implemented during the extension. Statistically significant improvements (P < .004) were noted in mean percentage change from baseline to 9 months and baseline to 48 months for hemoglobin (+19.2%, +21.7%, respectively), platelet counts (+67.6%, +157.8%, respectively), normalized liver volume (-18.2%, -42.8%, respectively), and normalized spleen volume (-49.5%, -79.3%, respectively). These significant clinical changes and safety profile led to phase 3 trials and highlight the potential of velaglucerase alfa as alternative therapy for type 1 Gaucher disease. The extension trial is registered at http://www.clinicaltrials.gov as NCT00391625.