The new findings center on a subset of 22 participants who received amyloid-removing drugs the longest, on average eight years. Long-term amyloid removal cut in half their risk of symptom onset, researchers reported Wednesday in the journal Lancet Neurology.

For the first time, scientists say, they have evidence that using a biologic drug to remove sticky beta amyloid plaques from the brains of people destined to develop Alzheimer’s dementia can delay the disease.