Enzyme replacement therapy with velaglucerase alfa in Gaucher disease: Results from a randomized, double-blind, multinational, Phase 3 study

A multicenter open-label treatment protocol (HGT-GCB-058) of velaglucerase alfa enzyme replacement therapy in patients with Gaucher disease type 1: safety and tolerability

Purpose:

To evaluate the safety of velaglucerase alfa in patients with type 1 Gaucher disease who received velaglucerase alfa in the US treatment protocol HGT-GCB-058 (ClinicalTrials.gov identifier NCT00954460) during a global supply shortage of imiglucerase.

Methods:

This multicenter open-label treatment protocol enrolled patients who were either treatment naïve or had been receiving imiglucerase. Patients received intravenous velaglucerase alfa every other week at a dose of 60 U/kg (treatment naïve) or 15–60 U/kg (previously treated).

Results:

A total of 211 (including six treatment-naïve) patients were enrolled. Among the 205 previously treated patients, 35 (17.1%) experienced an adverse event considered related to study drug. Among the six treatment-naïve patients, one had an adverse event considered related to study drug. Infusion-related adverse events occurred in 28 (13.3%) of the 211 patients and usually occurred during the first three infusions. De novo, nonneutralizing, anti–velaglucerase alfa antibodies developed during treatment in one (<1.0%) previously treated patient and none of the treatment-naïve patients.

Conclusion:

The currently observed safety profile was consistent with those previously reported for imiglucerase and velaglucerase alfa phase III clinical trials. These results support the safety of initiating treatment with velaglucerase alfa or transitioning patients from imiglucerase therapy to velaglucerase alfa therapy.

Enzyme replacement in neuronal storage disorders in the pediatric population

OPINION STATEMENT

In the past 15 years, for select lysosomal storage diseases, there has been a shift from symptom management to disease modification in terms of treatment strategy, mainly related to use of enzyme replacement therapy (ERT). Yet the application of ERT is for very few diseases, and while beneficial, ERT does not represent a cure. For some disorders, the advent of ERT has made a dramatic impact, while for others, benefits have been much more modest. Understanding of the long-term effects as well as the appropriate time for initiation of ERT is under exploration in a number of diseases, while the feasibility of ERT is still being established for others. No definite effects of ERT on central nervous system manifestations of lysosomal storage diseases have been observed for any disease to date. New strategies, including intrathecal enzyme replacement, gene therapy and substrate reduction therapy are being developed in animal models and clinical trials, which hopefully will begin a new era of nervous system disease modification in neuronal storage disorders.

Safety and efficacy of velaglucerase alfa replacement therapy for patients with type 1 Gaucher disease

Gaucher disease is a multisystem disorder caused by deficiency of β-glucocerebrosidase. Exogenously delivered enzyme replacement therapy (ERT) is currently standard of care. Since 1994, intravenously delivered recombinant ERT with imiglucerase (Cerezyme; Genzyme Corporation, Cambridge, MA, USA) improves hematological, visceral and skeletal features of Gaucher disease at dosages of 15-60 units/kg bodyweight/infusion, administered every other week (EOW). Velaglucerase alfa (VPRIV^®; Shire HGT, MA, USA) is a human wild-type-sequenced ERT produced in human cell lines using proprietary Gene-Activation^® technology (Shire HGT). This article describes the results of a Phase I/II seminal trial in treatment-naive non-neuronopathic patients (including stepwise dose reduction to 30 units/kg/EOW) and three Phase III trials (two doses: 45 or 60 units/kg/EOW; switch-over from imiglucerase at identical dose; head-to-head with imiglucerase, 60 units/kg/EOW) and Phase III extension trial. Velaglucerase alfa was approved in 2010 in many countries; based on clinical trial experience, it is safe and effective in treatment-naive and switch-over patients, children and adults, splenectomized patients and those with an intact spleen.

Enzyme replacement therapy and substrate reduction therapy in lysosomal storage disorders with neurological expression

Lysosomal storage diseases (LSD) are inborn errors of metabolism secondary to lysosomal enzyme defects and are characterized by a progressive accumulation of nondigested macromolecules provoking cellular dysfunction and clinical manifestations. The diagnosis of these diseases can be confirmed easily in most cases by immuno-enzymatic techniques and molecular biology. Even though these enzymatic deficits result in an accumulation of pathological substrates, the underlying mechanisms responsible for the pathogenesis of the disease are not entirely known. Nevertheless, the distribution of the accumulated material determines the affected organs. More particularly in the central nervous system (CNS), neurons are often involved due to the accumulation of storage material and their incapacity of renewal. LSD can be responsible for mental retardation or for a neurodegenerative course in the central nervous system. The peripheral nervous system and the muscle can also be severely impaired. Hematopoietic stem cell transplantation was the first therapy, demonstrating efficacy especially on the neurological involvement of various LSD. Enzyme replacement therapy is now available for Gaucher disease, Fabry disease, mucopolysaccharidoses type I, type II, and type VI, and Pompe disease. Inhibition of the synthesis of the accumulated substrate by small molecules which also have the capacity to diffuse through the blood-brain barrier is another treatment option. New therapeutic strategies using the properties of molecular chaperones and of read-through molecules for nonsense mutations have been studied in vitro and hopefully will soon find clinical applications while intrathecal enzymes are currently studies in clinical trials for MPSII, MPS IIIA and MLD.