BACKGROUND: Recently, collaboration between regulators and payers was set up and was mainly focused on evidence generation along product clinical development. However, neither the regulatory path nor the new active substance status (NASs) was considered. Granting NASs will provide the product with 8 years of data protection and 2 years of market exclusivity during which no generic could enter the market. OBJECTIVE: To review the economic impact (for payers) of NASs granted by the European Medicines Agency (EMA) for dimethyl fumarate (DMF), developed by Biogen and approved for multiple sclerosis (MS) as Tecfidera((R)) on 3 February 2014. METHOD: We reviewed the available DMF-containing products and identified their indication and price through relevant databases and official Web sites. The economic impact of Tecfidera((R)) on payers’ budgets was calculated assuming NASs was or was not granted. The forecast was identified in Datamonitor. RESULTS: Results identified four products already containing DMF as the main or unique active substance. This would have potentially prevented Tecfidera((R)) from being granted NASs. The EMA Committee for Medicinal Products for Human Use (CHMP) denied Tecfidera((R)) NASs and, following a company appeal, reversed its position opening as polemic. The impact of that decision has been evaluated at euro7 to euro10 billion over a 10-year period. CONCLUSION: NASs is a critical decision because it does have a major budget impact for payers, and it prevents generic competition. Current European Union (EU) regulations on that topic are unclear and open up too many interpretations thus distorting fair trade and affecting payers’ bills. Greater clarity and more stringent rules are required to prevent mistrust of this EMA decision.