There are many success stories. Here are a few:

Deaths Reduced by 97%
Viet Nam reduced malaria death 97% in five years, thanks to free treatment and insecticide treated nets. The number of malaria cases fell by almost 60%. By focusing on training, reporting, mobile health teams, and volunteer workers, the government made malaria a priority. Artemisinin was developed and locally manufactured. Additionally the govenement expanded preventative measures. The number of people covered by ITNs jumped from 300,000 to 10 million in five years. The nets were free.

To read more about this amazing story, see the WHO article Viet Nam Reduces Malaria Death Toll by 97% within Five Years.