The EMA recommended approval for Drugs for Neglected Diseases initiative (DNDi) and Sanofi's fexinidazole for sleeping sickness. DNDi, a non-profit drug developer, celebrated the European approval as a first all-oral treatment for the parasitic tropical disease and the first new chemical entity that they have developed through to approval.

Fexinidazole is a 5-nitroimidazole derivative that was discovered in the 1980s by Hoechst (now Sanofi) and then abandoned for strategic reasons. DNDi and its collaborators rediscovered the drug while screening for anti-parasitic activity in 2005, and DNDi partnered with Sanofi to develop, manufacture and distribute the drug in 2009. DNDi says it executed this repurposing work for US$55 million, with funding from seven European countries, the Bill & Melinda Gates Foundation, Médecins Sans Frontières and others. DNDi hopes to apply this low-cost repurposing model more broadly.

Regulators approved at least two other repurposed or reprioritized drugs for neglected and tropical diseases in 2018. In June, the FDA approved Medicines Development for Global Health's (MDGH's) moxidectin for river blindness. Moxidectin is a macrocyclic lactone with a history as a veterinary anthelmintic drug. In July, the FDA approved the Medicines for Malaria Venture (MMV) and GlaxoSmithKline's tafenoquine for Plasmodium vivax malaria. Tafenoquine was discovered in 1978 as a potential anti-malarial, but languished in development lingo until the 2000s.

Both of these US approvals came with priority review vouchers (PRVs). MDGH plans to sell its PRV to enable its future non-profit drug development work. In a recent Viewpoint in PLoS Neglected Tropical Diseases, scientists from the WHO and MDGH caution that oversupply of PRVs, market values of less than $100 million for PRVs and other factors could undermine the ability of PRVs to support drug development costs.

MDGH estimates that the total cost to bring moxidectin to market probably exceeded $50 million. SIGA sold a PRV, gained for its approval of a smallpox drug, for $80 million in November.