Interferony-β představují účinnou léčbu klinicky izolovaného syndromu (CIS – clinically isolated syndrome) a roztroušené sklerózy (RS) v 1. linii terapie. Účinnost může být negativně ovlivněna rozvojem neutralizačních protilátek (NAbs – neutralizing antibodies) proti interferonům-β a špatnou adherencí pacientů k léčbě, v důsledku čehož pacienti zažívají častěji relaps svého onemocnění. Tyto aspekty nebývají dostatečně zachyceny a popsány v rámci klinických studií III. fáze, na rozdíl od běžné klinické praxe. Při definování skutečné přidané hodnoty konkrétního interferonu- β (jeho léčebného účinku v reálných podmínkách) je pak nutno tyto aspekty (výskyt NAbs, adherence) vzít maximálně v potaz. Intramuskulární (i. m.) interferon-β1a se vyznačuje vysokou adherencí a nízkým výskytem NAbs.

Background: Interferons- β represent effective treatment of first-line therapy clinically isolated syndrome (CIS) and multiple sclerosis (MS). Effectiveness may be negatively affected by development of neutralizing antibodies (NAbs) against interferon- β and non-adherence of patients, resulting in increased number of relapses. These aspects are not sufficiently captured by the phase III clinical trials compared to situation in clinical practice. Objective: o ompare clinical benefits (reduce of number of relapses) and costs associated with MS treatment with one of the interferon- β in the Czech Republic in five-year horizon based on development of NAbs and patient non-adherence. Intramuscular (IM) interferon- β 1a is characterized by very high adherence rate and low rate of NAbs production. Methods: Markov cohort model was developed with one-year cycle length. In the Czech Republic, patients with MS initiate treatment with one of the interferon- β . NAbs- -positive patients (in the model, NAbs are detected during the second year of treatment and thereafter) are switched/ escalated to a different disease modifying drugs; DMD (glatiramer acetate, fingolimod, natalizumab). If patients experience two or more relapses during one year of treatment, they are escalated to fingolimod or natalizumab. Adherence data, development of NAbs, relapse rate and costs were sourced from the literature. Results: One hundred patients, who initiated treatment with IM interferon- β -1a, experienced 287 relapses over years. Those, who started treatment with subcutaneous (SC) interferon- β 1a and interferon- β 1b , experienced by 15 and 19 relapses more. In one hundred patients, total cost of treatment with IM interferon- β 1a as 6.4 million € . This was about 139-200 thousand € less compared to SC interferon- β 1a and interferon- β 1b . Hence incremental cost-effectiveness ratio was –262 thousand € /relapse avoided and –285 thousand € /relapse avoided. Conclusions: Intramuscular interferon- β -1a represents dominant intervention in MS treatment, i.e. cost-saving treatment from payer’s perspective and simultaneously more efficacy intervention in terms of reduction in number of relapses due to better patient adherence and lower incidence of NAbs compare to the other interferons- β in the Czech Republic. The one-way sensitivity analyses showed that results are the most sensitive to DMD costs and relapse rate.

VALUE OUTCOMES s r o Praha

Převzato z Farmakoterapie 2014; 10(6): 758-768

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