Enzyme therapy in Fabry disease: severe adverse events associated with anti-agalsidase cross-reactive IgG antibodies.

AIMS: To report a severe adverse event related to enzyme replacement therapy with agalsidase in an hemizygous male patient treated for Fabry disease.
METHODS: Retrospective analysis of clinical, radiological and biochemical data in a patient who suffered adverse events related to both agalsidase alfa and agalsidase beta treatments.
RESULTS: A hemizygous male patient was first treated for Fabry disease with agalsidase alfa. After more than 1 year of therapy, infusion-related symptoms necessitated systemic steroids and antihistaminic therapy. Decline in kidney function prompted a switch for agalsidase beta. Anaphylactoid shock occurred after the second infusion. No serum IgE antibodies were disclosed. Skin-test reactivity to agalsidase beta was negative. Following a published rechallenge infusion protocol, agalsidase beta was reintroduced, leading to a second anaphylactoid shock episode. Enzyme replacement therapy was stopped and the patient was treated with symptomatic therapy only. This case was referred to the pharmacovigilance department.
CONCLUSION: The negativity of immunological tests (specific anti-agalsidase IgE antibodies and skin tests) does not rule out the risk of repeated anaphylactoid shock following agalsidase infusion.