Shares of Seattle Genetics were up 6% at $119.05 after the bell.
The drug, Padcev, is the first FDA approved treatment in the United States for patients with advanced or metastatic urothelial cancer, the companies said.
The drug will treat patients with advanced bladder cancer whose disease has progressed even after treatment with immunotherapy and chemotherapy.
The American Cancer Society estimates 17,670 people will die from bladder cancer in the United States this year.
The continued approval of the drug may depend upon verification of clinical benefit in confirmatory trials, the companies said, adding that a late-stage study is underway.
The FDA's accelerated approval program allows conditional approval of a medicine that fills an unmet medical need for a serious condition.