Johnson & Johnson's unit Janssen Pharmaceuticals Inc. discontinued the development of its investigational drug atabecestat, which was being developed to slow cognitive decline in people at risk for Alzheimer's dementia.

The company stopped the clinical program for the drug after some study participants recieving atabecestat, which blocks an enzyme called BACE, showed an increase in liver enzymes that were found to be "serious in nature."

Based on an evaluation of liver safety data from its studies, the J&J unit stopped the screening, randomization and dosing of atabecestat in its phase 2b/3 study in late-onset preclinical stage Alzheimer's disease and in a phase 2 long-term safety study.

The company concluded that the benefit-risk ratio was no longer favorable to continue development of atabecestat in patients with late-onset preclinical stage Alzheimer's disease.

More than 600 people received atabecestat or placebo in these studies. The company is updating the study protocol for longer-term follow up of participants who received atabecestat after they discontinue treatment.

In April, Janssen signed a collaboration agreement with Miraca Holdings Inc. unit Fujirebio Inc. to develop and commercialize atabecestat.