The problem of an adequate choice of a treatment method in multiple sclerosis (MS) remains one of the most urgent in modern neurology. The number of patients and the cost of drugs are increasing, leading to an increased MS societal burden. However, treatment costs can be reduced due to the introduction of generic drugs, including domestic ones, which price is significantly lower.Objective: to assess the attitude of Russian patients to the reproduced disease modifying therapies (DMTs) and features influencing an attitude to the replacement from the original to the reproduced drug.Patients and methods. We interviewed 300 patients from six regions of the Russian Federation, receiving interferon beta-1a 44 μg, interferon beta-1b, glatiramer acetate, and teriflunomide, who had an experience of switching from an original drug to a domestic biosimilar drug or generic not earlier than 2009.Results and discussion. The majority of patients (63%) do not notice any changes due to drug replacement from the original to the generic one, some (28%) experience a deterioration in their well-being, and others (7%) experience an improvement in their condition. Young patients (up to 30 years) are relatively less likely to notice a deterioration in well-being after drug replacement. The clinical deterioration after drug replacement is much more often experienced by the patients whose drug was replaced in a pharmacy (74% of cases) and not by the attending clinician (only 54% of cases of deterioration). The majority (87%) of patients with relapsing-remitting MS (RRMS) did not interrupt the treatment after replacement; 13% of respondents reported that they had stopped taking the drug. Among them, there were much more patients whose drug was replaced in a pharmacy, and not due to clinician recommendation (more than 80% of such cases). Adverse reactions to a new drug are another reason for drug withdrawal (20% of all withdrawals). Patients receiving interferon beta-1b have a higher negative attitude towards domestic DMTs: 52% of the respondents gave negative feedback (compared to 20–35% in other groups). Relatively higher loyalty to Russian DMTs was observed in patients receiving interferon beta-1a (20% of negative feedback, which is noticeably lower than in other groups) and teriflunomide (a relatively higher proportion of positive feedback to Russian drugs – 25% compared to 11–16% in other groups). The majority (76%) of the respondents noted that they are interested in learning more about the development and registration of new Russian drugs.Conclusion. The majority of RRMS patients do not tend to have a negative attitude towards Russian DMTs. Consequently, the proportion of ratings in favor of Russian DMTs exceeds the weight of ratings against them. The key priority in the formation of loyalty to Russian DMTs should be changing the perception of adverse reactions. This will significantly increase the adherence to therapy and the quality of the provided treatment.
