Life-threatening hypersensitivity reactions, including anaphylaxis, have been reported in patients treated with enzyme replacement therapies, including FABRAZYME. In clinical trials and postmarketing safety experience with FABRAZYME, approximately 1% of patients developed anaphylaxis or severe hypersensitivity reactions. Reactions have included localized angioedema (including swelling of the face, mouth, and throat), bronchospasm, hypotension, generalized urticaria, dysphagia, rash, dyspnea, flushing, chest discomfort, pruritus, and nasal congestion.

In clinical trials with FABRAZYME, 10 of 238 patients developed IgE antibodies or skin test reactivity specific to FABRAZYME. Two of six patients in the rechallenge study discontinued treatment with FABRAZYME prematurely due to recurrent infusion-associated reactions. Four serious infusion-associated reactions occurred in three patients during FABRAZYME infusions, including bronchospasm, urticaria, hypotension, and development of FABRAZYME-specific antibodies. Other infusion-associated reactions occurring in more than one patient during the study included rigors, hypertension, nausea, vomiting, and pruritus.

Higher incidences of hypersensitivity reactions were observed in adult patients with persistent anti-FABRAZYME antibodies and in adult patients with high antibody titer compared to that in antibody-negative adult patients [see Adverse Reactions (6.2)].

Anaphylaxis has occurred during the early course of enzyme replacement therapy and after extended duration of therapy. Administration of FABRAZYME should be supervised by a healthcare provider knowledgeable in the management of hypersensitivity reactions including anaphylaxis. Prior to FABRAZYME administration, consider pretreating with antihistamines, antipyretics, and/or corticosteroids. Initiate FABRAZYME in a healthcare setting with appropriate medical monitoring and support measures, including access to cardiopulmonary resuscitation equipment.

  * If a severe hypersensitivity reaction (e.g., anaphylaxis) occurs, discontinue FABRAZYME and immediately initiate appropriate medical treatment, including use of epinephrine. Consider the risks and benefits of re-administering FABRAZYME following severe hypersensitivity reactions (including anaphylaxis). Inform patients of the symptoms of life-threatening hypersensitivity reactions, including anaphylaxis and to seek immediate medical care should symptoms occur.
    * Consider testing for IgE antibodies in FABRAZYME-treated patients who experienced severe hypersensitivity reactions, including anaphylaxis and consider the risks and benefits of continued treatment in patients with anti-FABRAZYME IgE antibodies. There are no marketed tests for antibodies against FABRAZYME. If testing is warranted, contact Genzyme Corporation at 1-800-745-4447 [see Adverse Reactions (6.2)].
    * Patients who have had a positive skin test to FABRAZYME or who have tested positive for FABRAZYME-specific IgE antibodies have been rechallenged with FABRAZYME using a rechallenge protocol. Rechallenge of these patients should only occur under the direct supervision of qualified personnel with appropriate medical monitoring and support measures readily available [see Dosage and Administration (2.3) and Adverse Reactions (6.2)].