Pharma giant Biogen and its Japanese partner Eisai have made the decision to halt two phase 3 trials of aducanumab, a drug created to slow Alzheimer’s by targeting brain-destroying beta-amyloid fragments. An independent monitoring committee decided that the drug was unlikely to benefit patients compared with a placebo.

This failure follows an earlier setback for fellow giant Roche in January, when it announced a halt to human trials of its Alzheimer’s drug crenezumab. As with Biogen’s drug, the early final result showed the drug neither reversed nor slowed the damage from Alzheimer’s.

Aducanumab was created by isolating a particular antibody in immune cells from particularly cognitively healthy senior citizens, which seemed to target the beta-amyloid proteins. Early results showed that the antibody safely cleared such plaques and improved cognitive functions.

The failure of the drug further weakens the beta-amyloid hypothesis in Alzheimer’s research, which suggests that Alzheimer’s is caused by debris containing the beta-amyloid protein.

During aducanumab’s development Biogen invested heavily in its success, resisting calls to diversify for protection.