A 32-year-old woman with severe allergic asthma requiring frequent oral corticosteroid courses has a total IgE of 350 IU/mL and positive skin tests to perennial allergens. Which biologic is specifically indicated here and what does it bind?

• A Omalizumab, binding the Fc portion of free circulating IgE ✓
• B Mepolizumab, binding interleukin-5
• C Benralizumab, binding the IL-5 receptor alpha on eosinophils
• D Reslizumab, binding interleukin-5 in the airway lumen

Explanation

Omalizumab is a humanized monoclonal antibody against the C epsilon 3 domain of IgE. It binds free circulating IgE, preventing its attachment to Fc epsilon RI on mast cells and basophils, thereby reducing effector cell activation. Dosing depends on body weight and baseline serum IgE. The IL-5 agents listed are eosinophil-targeted biologics used for eosinophilic phenotypes rather than allergic IgE-driven disease.

Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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