Anti-α-galactosidase A antibody response to agalsidase beta treatment: data from the Fabry Registry.

Agalsidase beta, a form of recombinant human α-galactosidase A (αGAL), is approved for use as enzyme replacement therapy (ERT) for Fabry disease. An immunogenic response against a therapeutic protein could potentially impact its efficacy or safety. The development of anti-αGAL IgG antibodies was evaluated in 571 men and 251 women from the Fabry Registry who were treated with agalsidase beta. Most men developed antibodies (416 of 571, 73%), whereas most women did not (31 of 251, 12%). Women were also significantly more likely to tolerize than men; whereas 18 of 31 women tolerized (58%, 95%CI: 52%-64%), only 47 of 416 men tolerized during the observation period (11%, 95% CI: 8%-15%). Patients who eventually tolerized had lower median peak anti-αGAL IgG antibody titers than patients who remained seropositive at their most recent assessment (400 versus 3200 in men, 200 versus 400 in women, respectively). Patients with nonsense mutations in the GLA gene were more likely to develop anti-αGAL IgG antibodies than patients with missense mutations. Approximately 26% of men (151 of 571) reported infusion-associated reactions (IARs), compared to 11% of women (27 of 251). Men who developed anti-αGAL IgG antibodies were more likely to experience IARs compared to those who remained seronegative. Nine percent of seronegative men and women (34 of 375) reported IARs. The majority of IARs occurred during the first 6 to 12 months of agalsidase beta treatment and decreased over time, in both seroconverted and seronegative patients.

The long-term international safety experience of imiglucerase therapy for Gaucher disease.

BACKGROUND: Gaucher disease is a lysosomal storage disorder resulting from a deficiency of the lysosomal enzyme glucocerebrosidase. Since approval by the FDA in 1994 and EMEA in 1997, enzyme replacement therapy with Cerezyme (imiglucerase for injection) has been the standard of care for the treatment of Gaucher disease. OBJECTIVE: To review the long-term international safety experience of imiglucerase from 1994 through 2004. MATERIALS AND METHODS: All spontaneous adverse event reports captured in the pharmacovigilance database for imiglucerase from 1994 through 2004 were analyzed. All adverse events were classified using the current version of the Medical Dictionary for Regulatory Activities (MedDRA). Patients without prior exposure to imiglucerase from 1994 through 2005 were assessed for the development of antibodies to imiglucerase as detected by enzyme-linked immunosorbant and radioimmunoprecipitation assays. RESULTS: Analysis of the long-term safety experience with imiglucerase therapy demonstrates a stable and low rate of adverse events and seroconversion from 1994 through 2005. The majority of frequently reported adverse events related to imiglucerase were infusion-associated reactions which were predominantly self-limiting in nature and did not require discontinuation of treatment. Between 1994 and 2005, IgG antibodies to imiglucerase were detected in approximately 15% of treatment-naïve patients. CONCLUSIONS: The long-term stability of reported events and seroconversion is a reflection of a well-characterized cell expression system and a mature quality-controlled manufacturing process. Imiglucerase is a safe therapy for the treatment of Gaucher disease with a stable and low rate of reported adverse events and seroconversion.