Eli Lilly & Co. reports that it has stopped a mid-stage trial of an experimental Alzheimer’s drug designed to mimic the effect of a rare genetic mutation that may protect against the disease.

The drug was in the second of three phases of clinical trials typically required before regulatory approval and was being tested in about 150 patients.

The trial ended after participants showed abnormal liver biochemistry.

More than 5 million Americans have Alzheimer’s which is the sixth leading cause of death in the U.S. according to the Alzheimer’s Association.

There is no cure for Alzheimer's.