AstraZeneca (AZ), Britain’s second-largest pharmaceuticals group, has cast fresh doubts over the prospects of one of its few remaining drugs in the late stages of development.

If successful, AGI-1067, an experimental treatment for atherosclerosis, or hardening of the arteries, is a potential blockbuster likely to generate billions of dollars a year in sales for AZ.

But in an interview with The Times, David Brennan, the group’s chief executive, sounded a gloomy note on the chances of success for the drug.

“We have a low probability of success from our perspective on it,” he said, adding that it was a “very high-risk project”.

Following a series of high-profile failures, AGI-1067 is one of just a handful of drugs that AZ has left in its pipeline of new products in advanced Phase III trials.

The company is seen as seriously vulnerable to any more disappointments over potential blockbusters. In October, £4.1 billion was wiped from its market value in a single day after it admitted that its stroke treatment, NXY-059, did not work.

Results of the group’s latest AGI-1067 study on 6,000 people are due in the first quarter of 2007.

The drug uses a scientific mechanism that remains unproven in humans and has been viewed as high-risk. UBS, the Swiss bank, this month cut its rating on the Anglo-Swedish company from “neutral” to “reduce” on expectations that the drug might fail.

“We believe there is a possibility that it could work, based on the Phase II data,” Mr Brennan told The Times. “It’s the same reason we went forward with NXY [a stroke drug that failed in trials in October].”

Mr Brennan continued: “If we get it, it will be significant. If we don’t, we have three other products in our pipeline that are moving along in Phase III — two oncology products and a platelet inhibitor — and we are actively looking for others.”

AZ struck a $50 million licensing deal for the rights to AGI-1067 with a US company called AtheroGenics in 2005.

“We bought an option for it if it’s successful,” Mr Brennan said. “So if it’s not, it cost us $50 million. If it is, we have a tremendous opportunity to develop a drug that has a new mechanism of action and will have demonstrated clinically significant decreases in morbidity and mortality.”

Mr Brennan declined to comment on AZ’s decision to consider a wide-ranging shake-up of its distribution chain in Britain.

The company has said that it is considering a variety of options designed to streamline its UK supply network. These may include handling UK distribution of its products on its own, with the assistance of a small number of distributor companies. AstraZeneca issued an invitation to tender to a variety of potential partners earlier this month, but has said that no final decisions have yet been taken.

Mr Brennan did say that AZ is facing growing pressure around the world from medicine counterfeiters. Counterfeiting is the same reason given by Pfizer, a rival to AZ, for striking a deal with UniChem to distribute all its products in the UK via a single channel.

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