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Autumn 2013, Vol. 21 No. 3

Hong Kong J. Dermatol. Venereol. (2013) 21, 114-123


Original Article

Evaluation of clinical efficacy and tolerability of azathioprine in adult Chinese atopic dermatitis patients in Hong Kong with pre-treatment thiopurine methyltransferase assessment

硫唑嘌呤在香港華裔異位性皮膚炎成年患者中的功效及耐受性評估,暨治療前硫嘌呤甲基轉移酶檢測

SM Wong 黃思敏 and KM Ho 何景文

Abstract

Background: Azathioprine (AZA) has been proposed as an off-label option in treating moderate-to-severe atopic dermatitis. Pre-treatment thiopurine methyltransferase (TPMT) assessment is commonly used in western countries, but TPMT test is not commonly available locally. Objective: We sought to evaluate the efficacy and tolerability of AZA in adult Chinese atopic dermatitis patients with pre-treatment TPMT assessment. Methods: Patients with atopic dermatitis seen in all government skin clinics in Hong Kong were screened to receive AZA for 12 weeks. The target dose of AZA was 2.5 mg/kg/day. The primary outcome was the change in disease activity as measured by the Six-area, Six sign Atopic Dermatitis (SASSAD) scores after treatment. Result: Thirty-six patients were recruited. The data were analysed on an intention-to-treat basis. The mean age was 26.9 years (range 18-63) with a male-to-female ratio of 1.4:1. After a treatment duration of 12 weeks, the disease activity was reduced by 52.1% (95%CI 47.6-52.6%) (p<0.05). Twenty-one patients (58.3%) achieved at least 50% reduction in disease activity (SASSAD50). The reduction in disease activity parallelled a significant improvement of symptoms and quality of life. The overall drug tolerability was good. Two patients discontinued AZA due to neutropaenia but both had a normal TPMT level. Other recognised adverse events such as nausea, rash, and raised liver enzymes were also observed. Conclusion: AZA can be considered as an effective and well-tolerated systemic treatment for patients with moderate-to-severe atopic dermatitis. Close blood monitoring is still warranted despite a normal level of thiopurine methyltransferase.

背景:硫唑嘌呤已被提議為治療中度至嚴重異位性皮膚炎的一種標籤外的治療選項。治療前的硫嘌呤甲基轉移酶檢測已是西方國家的常規,但在本地卻未普及。目的:我們試圖評估華裔異位性皮膚炎成年患者對硫唑嘌呤治療的療效及耐受性,並在治療前進行硫嘌呤甲基轉移酶水平的檢測。方法:在香港的所有政府皮膚科門診,對異位性皮膚炎患者進行篩選,參與者其後接受硫唑嘌呤共十二週的療程,目標劑量是服用者每天每公斤體重計為2.5毫克。主要療效指標定為治療後由六區域六體徵評分法(SASSAD)得分所反映的病情改變。結果:本研究共招募三十六例病患,平均年齡為26.9歲(範圍是十八歲至六十三歲),男性與女性的比例為1.4:1。數據基本採用意向治療分析,經過十二週的治療時間,疾病活躍性的減幅為52.1%(95%CI 47.6-52.6%)(p<0.05)。二十例(58.3%)的疾病活躍性(SASSAD50)達到五成或以上的減幅。此外,疾病活躍性的減少,與生活質量及顯著的症狀改善並行發展。整體藥物的耐受性良好,只有兩名硫嘌呤甲基轉移酶水平正常的患者因為中性粒細胞減少而須停服硫唑嘌呤,而其他觀察到的不良反應則包括噁心、皮疹和肝酶升高。結論:硫唑嘌呤對中度至嚴重病情的異位性皮膚炎患者來說,可視為有效和耐受性良好的全身治療。服用者即使有著正常水平的硫嘌呤甲基轉移酶,緊密的血液監測仍是不可或缺的。

Keywords: Atopic dermatitis, eczema, azathioprine, thiopurine methyltransferase, TPMT

關鍵詞: 異位性皮膚炎,濕疹,硫唑嘌呤,硫嘌呤甲基轉移酶,TPMT