The stock rose 70.5p, or nearly 1.7%, to 4254.5p as the Food & Drug Administration (FDA) designated its durvalumab drug as a "breakthrough therapy".
Breakthrough therapy designation (BTD) is designed to speed up development of drugs for serious conditions which have shown encouraging early clinical results, improvements over existing treatments or potential to address significant unmet medical need.
AstraZeneca's senior vice-president and head of immuno-oncology in global medicines development, Robert Iannone, said: "Metastatic bladder cancer is an area of enormous unmet medical need.
"We are encouraged by this breakthrough therapy designation. We look forward to working closely with the FDA to bring durvalumab to bladder cancer patients as soon as possible."
The designation, based on early clinical data from a phase one trial in patients with advanced urothelial bladder cancer, is said to be the third BTD that AstraZeneca has received for an oncology medicine.