By Joel Werner | The Wire

A clinical trial for the drug semagacestat has been halted. Image: rodrigo senna

A clinical trial of a drug to treat Alzheimer’s disease has been stopped after US researchers found the drug was actually making patients worse.

The drug, called semagacestat, has been taken out of development by Eli Lilly & Co after it was discovered that patients taking the drug had faster cognitive decline and greater difficulties carrying out the activities of daily living than those given a placebo.

“The investigators have a drug monitoring committee and they’re always monitoring for side effects,” said Professor Henry Brodaty, lead investigator of the Australian trial.

“They did an interim analysis before the trial finished, and once they saw this trend they immediately sent around an email saying to stop.”

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The late stage trial has been stopped at all international sites, including one at the Prince of Wales hospital in Sydney. At present it is unclear whether the adverse effects seen in the U.S. trial have been observed elsewhere.

“All I have seen are the media reports, I haven’t seen the actual numbers,” said Brodaty. “Whether the differences are statistically significant or just random differences in favour of placebo over the drug I can’t tell just now.”

For the patients whose trial was halted, there is no interruption to their regular treatment schedule, and they will be offered the opportunity to participate in other drug trials.

“This was an add-on study – so they didn’t have to give up their normal treatment,” said Brodaty. “We have other trials that we’re recruiting for, and we’re hopeful that some of those will be successful, so we’ll let our patients know about those trials.”

The announcement has lead to speculation on Wall Street concerning the future of Eli Lilly & Co. Brodaty was not surprised, saying: “It’s a huge gamble for these companies.”

“They’re putting in lots and lots of money, and if an untoward side effect occurs or it doesn’t show a positive effect, the drug is dead and it’s back to the drawing board.”

Although a setback in the search for a cure for Alzheimer’s, failed drug trials do not significantly impact the treatment of the disease. Drug therapies are only a small part of each patient’s treatment.

“We’d all love to have a magic bullet,” said Brodaty. “If we could give everyone destined to get Alzheimer’s disease a vaccine … that would stop them developing it, then we wouldn’t need all the other things. But currently, drug treatment is just a small part of the package of interventions.”

Alzheimer’s disease currently affects 250 000 Australians. If you or a family member has Alzheimer’s disease and are interested in participating in a drug trial, call Lynne at the Sydney Centre for Clinical Cognitive Research on (02) 9382 3733.