NEW YORK (Reuters) - Merck & Co Inc on Tuesday said it will end another late-stage trial of an Alzheimer’s drug because it was unlikely to work, adding to the pile-up of failures to find an effective treatment for the mind-wasting disease.

The company was testing the drug, Verubecestat, in patients with very early, or prodromal, Alzheimer’s disease. It scrapped the study almost exactly one year after ending a different late-stage trial of the same drug in patients with mild to moderate Alzheimer’s disease.

Verubecestat belongs to a class of experimental Alzheimer’s drugs called BACE1 inhibitors that target an enzyme involved in the formation of the toxic amyloid protein that turns into plaques in the brains of Alzheimer’s patients.

There have been a number of high-profile failures in Alzheimer’s drug development in recent years. Pfizer Inc said last month that it was abandoning research to find new drugs aimed at treating Alzheimer’s and Parkinson’s disease.

Lilly previously endured multiple failures with its solanezumab, which also targets beta amyloid, but in a different way. In the most recent setback, Lilly said that drug failed to slow declines in mental capacity of patients with even mild symptoms.