LONDON, April 26 (Reuters) - A clinical study testing AstraZeneca's experimental immunotherapy drugs in lung cancer patients who have already received at least two previous treatments will take longer than initially expected to produce results.
According to an update on the website clinicaltrials.gov, run by the U.S. National Institutes of Health, the so-called ARCTIC study is now due to complete on Nov. 15. AstraZeneca had previously said it expected results in the first half of 2017.
A company spokeswoman said the delay was because the trial had not yet observed enough clinical events in patients.
"This trial, like most other oncology trials, is event-driven so it is not unusual for the timeline to change slightly," she said.
The Phase III ARCTIC study is testing whether durvalumab on its own or in combination with tremelimumab can increase overall survival or delay the time it takes for lung cancer to worsen, when given as a third-line treatment.
The durva/treme drug cocktail is viewed as a potential multibillion-dollar market opportunity for AstraZeneca. However, the number of patients who might receive third-line treatment is relatively small.
Investor attention is focused primarily on giving the drug combination to previously untreated, or first-line, patients. Results from the closely watched MYSTIC trial in this much larger patient group are expected mid-year.
Reporting by Ben Hirschler; Editing by Adrian Croft