Lilly says Alzheimer's antibody drug safe

By Julie Steenhuysen

CHICAGO (Reuters) - Eli Lilly and Co's antibody drug for Alzheimer's disease was safe and appeared to be dissolving sticky brain plaques, but a three-month study was too short to show any improvement in memory, company researchers said on Wednesday.

The infused therapy, known by the experimental name LY2062430, attempts to remove a brain-damaging protein called beta amyloid via antibodies that attach to individual, free-floating molecules of the protein before they can form clumps known as plaques.

"The safety profile for our antibody seems to be very, very good. We were not able to identify any side effects we could relate to the antibody," Dr. Eric Siemers, medical director of Lilly's Alzheimer's disease research, said in an interview.

That may be significant.

People with Alzheimer's disease have too much beta amyloid plaque in the brain, and the prevailing theory is that removing the plaque may slow disease progression.

Rivals Elan Corp Plc and Wyeth, which are developing a drug with a similar approach, said on Tuesday that 12 people in a larger, longer study treated with their antibody developed vasogenic edema, a condition marked by a build-up of fluid in the brain, although the side effect appeared to be manageable.

Siemers said the Lilly drug may avoid damaging the brain because it does not attack plaque. "It binds to individual amyloid beta molecules," he said.

FINDING THE TOXIN

"One of the big questions is what is really the toxic part of beta amyloid. There is good evidence that it is not the plaque itself," said Siemers, who presented the findings at an Alzheimer's Association conference in Chicago.

Lilly's study involved 52 people with mild-to-moderate Alzheimer's disease and 16 healthy people who received 30-minute infusions of the drug or a placebo for 12 weeks.

The goal was to test for safety and to see if tests of blood and spinal fluid could detect changes in protein levels that would suggest it was working.

They found that after giving the antibody, more beta amyloid appeared in patients' blood and spinal fluid. The company sees this as a sign the antibody is clearing out the beta amyloid.

They used a type of brain imaging known as SPECT to measure plaque in the brains of 24 Alzheimer's patients and 13 healthy people.

In people who got the highest dose of the antibody, a type of beta amyloid typically found only in plaque appeared in their blood. "It appears the plaque started to dissolve around the edges," Siemers said.

The study found no evidence that this made any difference at improving memory, but Siemers said researchers did not expect it would in such a short time.