This is a proposal to develop the orphan designated drug, nitisinone, for the treatment of a rare Mendelian disease, Alkaptonuria (AKU). Thanks to our existing successful fundamental and clinical research (cell models, animal models, natural history studies), we are now ready for this final stage of clinical development of nitisinone for AKU: a phase 3 clinical trial to prove efficacy. The results of DevelopAKUre will allow us to make the case to the European Medicines Agency for marketing authorisation of nitisinone for AKU, thereby contributing to the goal of the International Rare Diseases Research Consortium of developing 200 new therapies by 2020.