Prana Alzheimer's drug safe, shows some benefit

By Julie Steenhuysen

CHICAGO (Reuters) - The new drug PBT2 improves planning and thinking abilities in patients with Alzheimer's disease and cuts levels of a protein in spinal fluid that is associated with the disease, researchers said on Tuesday.

The drug, made by Prana Biotechnology Ltd (PBT.AX), aims to reduce levels of the protein called beta amyloid that forms sticky plaques in the brain.

"It reduced the level of beta amyloid in the spinal fluid. We think spinal fluid is the closest measure to what is happening in the brain," said Dr. Jeffrey Cummings of the University of California Los Angeles, chairman of Prana's research and development advisory board.

PBT2 is designed to keep beta amyloid from interacting with copper and zinc in the brain, which have been shown to promote the formation of beta amyloid plaques, which are thought to be toxic.

The primary goal of the study was to prove the compound was safe in patients with Alzheimer's. An earlier version of the drug, clioquinol, showed signs that it might work, but it also had some neurotoxic side effects.

"It's safe and well tolerated. This is a relatively new class of drugs that we have very limited experience with," said Cummings, who presented the findings at the Alzheimer's Association international conference in Chicago. The results were released online in the journal Lancet Neurology.

Cummings was encouraged because the drug showed signs that it reduced levels of the type of amino acids that form beta amyloid in spinal fluid.

In mice, the drug has shown it can restore normal function to brain connections or synapses that are impaired by beta amyloid, and helped improve brain function in the test animals.