Shortly after discontinuing two late-stage trials of Alzheimer's disease drug aducanumab, Eisai Co. Ltd. said it started a global late-stage study of another drug for the disease.

The Japanese drugmaker said it initiated a phase 3 study of BAN2401 in patients with early Alzheimer's disease.

The trial, dubbed Clarity AD or Study 301, involves 1,566 patients with mild cognitive impairment due to Alzheimer's disease or mild Alzheimer's disease dementia with confirmed amyloid pathology in the brain.

Alzheimer's disease is the most common cause of dementia. The disorder is characterized by the progressive loss of memory and other mental functions.

Clarity AD's main goal is the change from baseline in the cognitive and functional performance of the patients, including memory, orientation, judgement and problem solving, community affairs, as well as home and hobbies, and personal care, after 18 months of treatment.

The Tokyo-based pharmaceutical company, which is co-developing the investigational drug with Biogen Inc., will use the study's results to support a regulatory filing for the drug. BAN2401 previously failed to meet the main goals of a mid-stage trial known as Study 201 in December 2017.

Eisai and Biogen discontinued two late-stage trials evaluating aducanumab, another Alzheimer's disease drug, after analysis showed the studies were unlikely to meet their main goals.