Shares in AstraZeneca raced ahead on Friday after the pharmaceuticals giant announced a major breakthrough for a lung cancer drug.
The firm said that trials of Imfinzi showed it "significantly reduces the risk of disease worsening or death" in lung cancer sufferers.
The randomised trial produced "highly encouraging" results for patients with stage three lung cancer for whom surgery was not an option, AstraZeneca said.
Investors warmed to the potential of Imfinzi, which could help drive income at the firm.
The FTSE 100 firm's shares rose 6.5% to 5,057p in afternoon trading following the news.
Sean Bohen, the group's chief medical officer, said: "These are highly encouraging results for patients with locally-advanced lung cancer for whom surgery is not an option.
"We continue to explore Imfinzi's full potential as monotherapy as well as in combination with tremelimumab and other medicines in areas of continued unmet need across multiple types of cancer."
AstraZeneca said it will start to work with regulators around the world to bring Imfinzi to patients as soon as possible. The company said the disease affected around 100,000 patients in the G7 countries in 2016.
Nicholas Hyett, equity analyst at Hargreaves Lansdown, said: "The success of AstraZeneca's Pacific trial marks an important step forward for the group's immuno-oncology portfolio.
"Not only does the Imfinzi treatment look to have considerable potential in the treatment of lung cancer in its own right, but the underlying drug forms one half of the combined therapy being tested in the key Mystic trial."