Volume. 35, No. 2 july. 2011 - The Chest and Heart Association of ...

Incorporating Omalizumab into Asthma Management: A ReviewMd. Khairul Hassan Jessy et al.day, and had had at least one visit to the emergencydepartment in the past year. Patients requiringdaily oral corticosteroids to control their asthmamay be less likely to have a response toOmalizumab.A total serum IgE level should be measured in allpatients who are being considered for treatmentwith Omalizumab, because the dose of Omalizumabis determined on the basis of the IgE level andbody weight. The recommended dose is 0.016 mgper kilogram of body weight per international unitof IgE every four weeks, administeredsubcutaneously at either two-week or four-weekintervals (Table 1). This dose is based on theestimated amount of the drug that is required toreduce circulating free IgE levels to less than 10IU per milliliter.Monitoring of total serum IgE levels during thecourse of therapy with Omalizumab is notindicated, because these levels will be elevated asa result of the presence of circulating IgE–anti-IgE complexes. No other laboratory tests seem tobe necessary, since there have been no clinicallysignificant laboratory abnormalities noted duringtreatment. 7,9,10* Adapted from the Xolair package insert. Therecommended dose is 0.016 mg per kilogram ofbody weight per international unit of IgE everyfour weeks, administered subcutaneously at eitherfour-week or two-week intervals for adults andadolescents (persons 12 years of age and older) withallergic asthma. Dashes indicate that no doseshould be prescribed. 6Preparation for UseOmalizumab is supplied as a lyophilized, sterilepowder in single-use, 5-ml vials designed to delivereither 150 or 75 mg on reconstitution with sterilewater (not normal saline) for injection. The powderrequires 15 to 20 minutes or more to dissolve.There are fewer injection-site reactions when thesolution is not injected until it is completely clear.The solution is viscous and must be carefully drawnup into the syringe before it is administered. Theinjection itself may take 5 to 10 seconds toadminister. Once prepared, the drug must be usedwithin four hours if at room temperature or eighthours if refrigerated. Because of theserequirements for preparation and the high cost ofthe drug, some practitioners require patients toschedule appointments for injection, and many donot prepare the injection until the patient arrives.This results in visits that take 60 minutes or more,since 30 minutes of observation is recommendedafter the injection. In general, current asthmasymptoms are not a contraindication to theadministration of Omalizumab.Total serum IgE levels will generally increaseduring treatment, because of the presence ofcirculating IgE–anti-IgE complexes. Aninvestigative method for measuring free serum IgElevels has recently been reported and may providean opportunity for monitoring optimal Omalizumabdosing. In addition, recent in vitro studies of theeffect of Omalizumab on the accuracy andreproducibility of assays of total and allergenspecificIgE antibodies suggest that the use of aspecified Commercial assay may help optimizeTable-IDosing Schedule for omalizumab, According to the Baseline Serum IgE Leveland Body weight,Baseline SerumBody weightIgE Level 30-60 kg 61-70 kg 71-80 kg 81-90 kg 91-150 kgIU/mldose in milligrams30-100 150 150 150 150 300101-200 300 300 300 300 225201-300 300 225 225 225 300301-400 225 225 300 300 -401-500 300 300 375 375 -501-600 300 375 - - -601-700 375 - - - -123