Trials of Cerovive, a treatment to limit the damage caused by strokes and one of AstraZeneca's most important experimental drugs, have shown conflicting results in protecting patients, the company said yesterday.
AstraZeneca intends to continue two other big trials before drawing conclusions about the drug's effectiveness, and said it still planned to file for regulatory approval in the second half of 2006.
In a study of more than 1,700 patients, the drug was shown to reduce the disability caused by a stroke using one method of measurement; however, another found the drug made no difference to patients.
Cerovive has become more important to AstraZeneca after problems with its new blood-thinning drug, Exanta, and cancer treatment Iressa.
Both had been considered important to the firm's financial health but their potential is now thought negligible, making investors focus on the rest of the pipeline. Cerovive is licensed from American firm Renovis and the drug is one of only two from AstraZeneca in late-stage clinical trials.
Measuring the effects of a stroke objectively can be difficult. The Rankin scale scores patients on their ability to do everyday tasks and their need for nursing care. Another neurological stroke assessment requires doctors to measure patients' consciousness, facial muscle weakness and ability to hold up their limbs.
Cerovive made patients better in the first measure but not the latter, AstraZeneca revealed yesterday.
Professor Kennedy Lees at the University of Glasgow, the lead investigator for the clinical trials, said this might still be acceptable. "Regulatory authorities would not accept the neurological scale without the Rankin scale being positive but might do the other way around," he said.
The firm has not revealed exactly how much the drug helped patients, but a spokesman said they would publish the data in a journal or reveal it at an academic meeting. One analyst, who declined to be named, said the detail was needed before a judgment could be made.
"It is the difference between a patient doing up their own shoelaces in 45 seconds or 30 seconds, or whether or not they know their relatives," said the analyst.
· US regulatory scientists are to scrutinise Serevent, GlaxoSmithKline's asthma treatment, following warnings that it may increase the risk of asthma-related deaths.
Also known as Salmeterol, the drug was said to be risky by Dr David Graham, a regulatory scientist at the US food and drug administration, at a controversial senate hearing last year. The drug is one half of the asthma treatment Advair, the firm's best-selling drug.
The FDA's pulmonary and allergy advisory committee will look at the issue in July. In the study that showed an increased death risk, Serevent was not used in the way Glaxo recommends, analysts said.
