Velaglucerase Alfa for the Management of Type 1 Gaucher Disease

Abstract

Abstract Background Gaucher disease (GD) is the most common lysosomal storage disease, (frequency of 1:40,000 to 1:60,000). Ninety-Five percent of patients have type 1 (nonneuropathic type). Symptomatic patients with type 1 GD are treated with enzyme replacement therapy (ERT) to improve disease-induced effects on hemoglobin, platelets, and liver and spleen volume. Currently, several ERTs are available. Objective The goal of this article was to review the pharmacology, efficacy, and safety data available for the use of a recently approved ERT, velaglucerase alfa, for the treatment of type 1 GD in symptomatic pediatric and adult patients. Methods Serial searches of MEDLINE, EMBASE, and Cochrane databases for English-language, peer-reviewed, clinical data (using the search term velaglucerase alfa ) were completed, with the final search in November 2011. All identified, peer-reviewed published human data were used for this review. Due to minimal peer-reviewed published data, those data reported via clinical trial registries or in the form of published abstracts were included. The manufacturer was contacted and given the opportunity to submit supplemental data for consideration of inclusion by the author. Results Velaglucerase alfa is produced through gene activation technology and is identical to wild-type enzyme. As with other ERTs for type 1 GD, velaglucerase alfa targets accumulated glucocerebroside primarily within the lysosome of the macrophages in the affected organs and systems. When administered at doses of 60 U/kg intravenously, velaglucerase alfa follows linear pharmacokinetics and is rapidly eliminated, with a mean (SD) residence time or time for 63% of the dose to be cleared from systemic circulation of 14 (4) minutes. Four trials and early access program data reporting efficacy were identified for this review: 5 peer-reviewed publications, 3 clinical trial registry reports, and 1 abstract-only publication. Phase I/II data with an extension phase (n = 12) showed significant improvements (all, P z score slope for both lumbar spine (0.14 z score unit per year; P z score unit per year; P P 9 /L [95% CI, 23.97 to 77.78]; 45 U/kg, 40.92 × 10 9 /L [95% CI, 11.2 to 70.64]), spleen volumes (60 U/kg, −1.92% of body weight [95% CI, −3.04 to −0.79]; 45 U/kg, −1.87% of body weight [95% CI, −3.17 to −0.57]), and hepatic volumes (60 U/kg, −0.84% of body weight [95% CI, −1.58 to −0.11]). A subanalysis of the pediatric population showed clinical improvements at 12 months in both dosing groups: hemoglobin concentrations (60 U/kg, 1.74 g/dL [95% CI, 0.72 to 2.78]; 45 U/kg, 2.77 g/dL [95% CI, −0.99 to 6.53]), platelet counts (60 U/kg, 49.9 × 10 9 /L [95% CI, −32.1 to 131.9]; 45 U/kg, 60.3 × 10 9 /L [95% CI, −103.1 to 223.7]), spleen volumes (60 U/kg, −2.1 cm 3 [95% CI, −5.3 to 1.1]; 45 U/kg, −0.7 cm 3 [95% CI, −2.6 to 1.2]), and hepatic volumes (60 U/kg, −0.7 cm 3 [95% CI, −1.4 to 0.0]; 45 U/kg, −0.3 cm 3 [95% CI, −1.7 to 1.1]). Data comparing velaglucerase alfa with imiglucerase identified similar changes in hemoglobin concentrations at 1.624 g/dL and 1.488 g/dL, respectively, after 9 months of therapy. Safety was reported in 3 identified studies and in data reported from the early access program: 3 peer-reviewed publications, 3 studies reported in clinical trial registries, and 1 abstract publication. Patients experienced a minimal number of adverse effects, and most reactions were mild to moderate in severity; 1 patient developed an anaphylactoid reaction and was discontinued from the trial. Antibody formation has been described with velaglucerase alfa but when compared with that of imiglucerase, seroconversion is less frequent (1% and 23%, respectively). Dosing regimens, from 30 to 60 U/kg intravenously every other week, have been assessed. Currently, the manufacturer recommends 60 U/kg intravenously every other week; however, further studies and evaluation of current study dosing regimens are needed to determine if there is a lower effective dose. Conclusions Although a minimal amount of data are available for this relatively new biological agent, velaglucerase alfa reportedly is effective in the achievement and maintenance of therapeutic goals in type 1 GD in both treatment-naive and patients previously treated with imiglucerase. This agent has been reasonably well tolerated in clinical trials and may be considered for use in symptomatic patients with type 1 GD.