Prana Biotech Plunges 76%; Drug Fails in Alzheimer Study

Prana Biotechnology Ltd. (PBT) plunged as much as 76 percent in trading before U.S. exchanges opened after the company’s experimental drug for Alzheimer’s disease failed to help patients in a clinical trial.

The treatment, PBT2, didn’t show a statistically significant reduction in the levels of beta-amyloid plaques in the brains of people with mild Alzheimer’s, the Armadale, Australia-based company said in a statement today. PBT2 also led to no improvement in brain metabolic activity, cognition and function, Prana said.

“Whilst not meeting all of our hopes, this result does not deter us from the future development of PBT2, a safe and well-tolerated drug candidate for Alzheimer’s disease,” Chief Executive Officer Geoffrey Kempler said in the statement.

The failure adds to the list of once-promising experimental treatments for Alzheimer’s that have proven disappointing in clinical trials. Since 1998, there have been more than 100 unsuccessful attempts to develop a drug for the malady, which is the most common form of dementia. Worldwide about 35.6 million people have dementia, the World Health Organization estimated in 2012.

Prana’s American depositary receipts plunged 62 percent to $3.70 at 7:10 a.m. in New York. The ADRs rose 41 percent this year through yesterday, valuing the company at $423.5 million.

PBT2 aims to prevent the accumulation of amyloid plaques, growths in the brain that are hallmark of Alzheimer’s, by interfering with metal ions that let them aggregate. The mid-stage study, dubbed Imagine, looked at 42 people with Alzheimer’s. PBT2 was given to 27 of them, and the other 15 received a placebo.

To contact the reporter on this story: Phil Serafino in Paris at

To contact the editors responsible for this story: Phil Serafino at Marthe Fourcade, Thomas Mulier

Press spacebar to pause and continue. Press esc to stop.

Bloomberg reserves the right to remove comments but is under no obligation to do so, or to explain individual moderation decisions.

Please enable JavaScript to view the comments powered by Disqus.