Gon Yasuhiro, Ito Reiko, Maruoka Shuichiro, Mizumura Kenji, Kozu Yutaka, Hiranuma Hisato, Iida Yuko, Shikano Sotaro, Hashimoto Shu
Division of Respiratory Medicine, Nihon University School of Medicine, 30-1 Ohyaguchi-Kamicho, Itabashiku, Tokyo 173-8610 Japan.
Allergy Asthma Clin Immunol. 2017 Aug 31;13:39. doi: 10.1186/s13223-017-0211-z. eCollection 2017.
Omalizumab is a human IgG1 antibody against IgE used as a therapy for sever asthmatic patients with asthma. According to the guidelines of the Global Initiative for Asthma, omalizumab is an add-on drug at treatment step 5 that is used for severe asthma patients who are allergic to perennial allergens. The effects of omalizumab for severe asthma therapy have been validated in multiple clinical studies. However, the long-term effects of omalizumab on IgE production and possibility of resetting of administration dose of omalizumab remain unknown.
The serum total and free IgE levels were measured over time in a 63-year-old female patient with allergic asthma who was administered 375 mg omalizumab biweekly for 36 months. Her symptoms did not worsen and clinical course remained favorable after reducing the dose to 375 mg per month. The serum free IgE levels temporarily increased following a dose reduction of omalizumab. The serum free IgE trough level temporarily increased at 4 weeks after capable to reduce the dosage; however, thereafter, the serum free IgE level decreased to desired levels (below 30 ng/mL).
The present case shows the possibility of reducing the dose following the long-term use of omalizumab. Considering the high medical cost of omalizumab, the dose reduction may be a viable option. It may be useful to measure the serum free IgE level to appropriately identify patients in whom the dose can be reduced, and to carefully monitor the clinical course.
奥马珠单抗是一种抗IgE的人IgG1抗体，用于治疗重度哮喘患者。根据全球哮喘防治创议的指南，奥马珠单抗是治疗步骤5的附加药物，用于对常年性过敏原过敏的重度哮喘患者。奥马珠单抗治疗重度哮喘的疗效已在多项临床研究中得到验证。然而，奥马珠单抗对IgE产生的长期影响以及重新调整奥马珠单抗给药剂量的可能性仍不清楚。
对一名63岁的过敏性哮喘女性患者进行了长达36个月的观察，该患者每两周接受375mg奥马珠单抗治疗，期间定期检测血清总IgE和游离IgE水平。在将剂量减至每月375mg后，她的症状没有恶化，临床病程保持良好。奥马珠单抗剂量减少后，血清游离IgE水平暂时升高。在能够降低剂量后的第4周，血清游离IgE谷值水平暂时升高；然而，此后，血清游离IgE水平降至理想水平（低于30ng/mL）。
本病例显示了长期使用奥马珠单抗后降低剂量的可能性。考虑到奥马珠单抗的高医疗成本，降低剂量可能是一个可行的选择。检测血清游离IgE水平可能有助于适当识别可以降低剂量的患者，并仔细监测临床病程。
