When is enough enough? The need for a robust pipeline of high-quality antimalarials.

Malaria kills an estimated one million people a year--mostly children under 5. State-of-the-art medicines known as artemisinin combination therapies (ACTs) are available, and successfully cure up to 99% of patients. Additionally, insecticide-treated bed nets and insecticide spraying are helping to prevent the disease, while a vaccine is in clinical development. With all these tools at hand, you might ask why we need more new medicines. Why not just concentrate on improving the distribution of existing ones? Whilst access to medicines is clearly a major challenge, there are several reasons why new antimalarials are urgently needed--and will continue to be needed until we have finally defeated the parasite. First, the emergence of drug resistance to any infectious disease treatment is inevitable. A range of medicines with varying mechanisms of action are needed to stem the tide of drug resistance as well as fill the gap when it takes hold. Second, malaria is a disease predominantly affecting children and expectant mothers. These vulnerable patient groups require medicines tailored to their needs with robust safety profiles. Third, of the five species of malarial parasites that infect humans, two can relapse, and there is currently no safe medicine to combat the relapse for all patients. Finally, in order to ultimately eradicate malaria, medicines are needed that go a step beyond simple treatment and break the transmission of the parasite from patient to patient.