Modified protocol for desensitization to glatiramer acetate

MODIFIED PROTOCOL FOR DESENSITIZATION TO GLATIRAMER ACETATE To the Editor: I am grateful to Bains et al1 for sharing their protocol for glatiramer acetate desensitization. A 46-year-old woman with multiple sclerosis was self-administering glatiramer acetate injections daily for approximately 4 weeks. She reported frequent injection site reactions that were tolerable, but on 1 occasion she developed acute onset of localized urticaria, nasal congestion, palpitations, diffuse flushing, and hoarseness within minutes of injection. Her injections were discontinued. Results of percutaneous skin testing to full-strength glatiramer acetate were positive, with negative results in a control subject. We attempted desensitization per the protocol published by Bains et al.1 When the patient reached the first full-strength dose (0.2 mL), she developed acute onset of palmar pruritus and throat irritation, followed by diffuse and severe flushing and nasal congestion. She had no respiratory or cardiac manifestations of anaphylaxis and no associated angioedema. The desensitization was aborted, and she was treated for anaphylaxis. Given the necessity of the medication, we reattempted the desensitization 2 weeks later. The protocol published by Bains et al1 was modified to include a more gradual increase in doses, and the patient was premedicated with high-dose prednisone (50 mg given orally Disclosures: Authors have nothing to disclose. © 2010 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.anai.2010.06.003

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13, 7, and 1 hour before) and diphenhydramine (50 mg given orally 1 hour before). The protocol was modified so that the following doses of the full strength (20 mg/mL) were administered after the 1-mL dose of 2 mg/mL: 0.05, 0.1, 0.2, 0.3, and 0.4 mL. The patient experienced mild facial flushing after the last dose was administered, but this resolved without intervention. The desensitization was successful. She was maintained on a tapering dose of prednisone for 10 days after the procedure and on cetirizine, 10 mg daily, for 21 days after the procedure. She has been receiving glatiramer acetate daily and has been tolerating it well, although she continues to experience local site reactions, including mild pruritus. It is unknown whether this desensitization was successful because of the more gradual increase in doses, the aggressive premedication, or both. This case (1) displays the potential beneficial role of premedication in those who fail traditional desensitization and (2) proposes a modified and more gradual protocol for desensitization to glatiramer acetate. SHASHANK S. SHETH, MD* MARK A. POSNER, MD* *Allergy & Asthma Specialists PC Blue Bell, Pennsylvania [email protected] 1. Bains SN, Hsieh FH, Rensel MR, et al. Glatiramer acetate: successful desensitization for treatment of multiple sclerosis. Ann Allergy Asthma Immunol. 2010;104: 321–325.

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