The serum to Bledsoe's disease was a cure that prevented the lethality of Bledsoe's.
This serum was created by Doctor Kaaldar, who also engineered a strain of the disease. The serum required a brief period of time to take effect, during which the person afflicted with the disease would no longer suffer its more serious symptoms, but would remain contagious until their organism was cleared.
C. 0 ABY, Luke Skywalker contracted Bledsoe's from a squill bite on Tatooine. He and Anduvil managed to get in the Imperial Garrison Base, and forced Dr. Kaaldar to give Luke the serum, which prevented his death.