(Adds details, competition)
Oct 21 (Reuters) - Merck & Co Inc said its immunotherapy, Keytruda, helped previously treated patients with advanced bladder cancer live longer in a late-stage study, prompting an independent monitoring panel to recommend stopping the trial early.
The blockbuster drug's benefit in patients with urothelial cancer, the most common form of bladder cancer, surpassed that of chemotherapy, meeting the main study goal of overall survival.
Bladder cancer occurs when cells in the urinary bladder start to grow uncontrollably. Urothelial carcinoma starts in the cells lining the bladder. Patients enrolled in the trial suffered from an advanced form of the cancer despite undergoing chemotherapy.
Keytruda, which belongs to a new class of medicines called PD-1 inhibitors that help the immune system unmask hidden cancer cells, generated second-quarter sales of $314 million.
The drug, along with rival Bristol-Myers Squibb & Co's Opdivo, is already approved to treat a common form of lung cancer.
Analysts expect that the treatments will rake in tens of billions of dollars in sales in the years ahead, as they are tested for other types of cancer.
A newer entrant to the immunotherapy space is Roche Holding AG, whose drug Tecentriq won U.S. approval in May for bladder cancer, followed by lung cancer this week.
(Reporting by Natalie Grover in Bengaluru; Editing by Martina D'Couto)