(Reuters) - London-listed shares of AstraZeneca fell on Tuesday after results from the company's lung cancer trials showed that its experimental precision drug did not significantly improve overall survival results for patients.
The stock fell as much as 5.6% to 119.98 pounds in early trade.
The overall survival, or OS rates, in the TROPION-Lung01 trial "did not reach statistical significance", the company said in a presentation at the World Conference on Lung Cancer in San Diego on Monday.
AstraZeneca's shares, which have gained nearly 18% this year, are set for their biggest one-day drop in seven months, if losses hold.
The late-stage trial has been closely watched by investors and analysts who forecast that the drug, known as Dato-DXd, could potentially be another best-selling medicine for AstraZeneca.
The drug belongs to a promising class known as antibody drug conjugates (ADC), which consist of tumour-seeking monoclonal antibodies that are combined with a cell-killing chemotherapy payload. It has been developed jointly with Japan's Daiichi Sankyo.
(Reporting by Radhika Anilkumar in Bengaluru; Editing by Sonia Cheema and Sherry Jacob-Phillips)