Eli Lilly’s Phase II study for an investigational drug for Alzheimer’s disease has been terminated due to abnormal liver biochemical tests. The company says that clinical study investigators have been informed.

The compound in question, a beta secretase (beta-site APP cleaving enzyme, BACE) inhibitor called LY2886721, was being tested as a once-daily therapy to slow down Alzheimer’s disease progression.

Jan M. Lundberg, Ph.D., executive vice president, science and technology, and president, Lilly Research Laboratories, said:

“While stopping this Phase II study for our BACE inhibitor is disappointing, patient safety is of utmost importance to Lilly. Discovering and developing medicines for devastating diseases like Alzheimer’s is fraught with many challenges, but Lilly’s 25-year commitment to bringing medicines to the millions of Alzheimer’s disease patients who are waiting will not wane.”

Abnormal liver biochemical test results were identified as part of the trial’s routine monitoring, the company informed. All participants in the human study with abnormal liver biochemical tests will be carefully monitored, Lilly added. Abnormal liver tests could be a sign of liver inflammation or damage.

According to data gathered so far, Lilly believes that the abnormal liver biochemical tests found in this trial are not linked to the mechanism of BACE. Therefore, the company will continue to develop BACE inhibitors for the treatment of Alzheimer’s. Lilly wrote in an online communiqué “Lilly will further evaluate this data prior to determining next steps for the entire LY2886721 clinical development program.”

BACE inhibitors decrease the production of amyloid-beta by blocking BACE1, an enzyme, which in turn may decrease accumulation of amyloid-beta. However, accumulation is due to imbalances of production and clearance of amyloid-beta. BACE inhibitors do not have any effect on the clearance of amyloid-beta, only its production. Merck & Co, Roche and Eisai are also working on BACE inhibitors for the same indication.

BACE inhibitors have the potential to become pharmaceutical blockbusters with annual sales of at least $3 billion if their efficacy and safety can be proven. There is no medication on the market today that can slow the progression of Alzheimer’s disease, the major cause of dementia. In just the USA, at least 5 million people live with this disease.

Lilly has been investigating another experimental drug for Alzheimer’s, called Solanezumab, a monoclonal antibody. An antibody is a protein produced by an immune cell. Monoclonal means that the immune cells are all identical (like identical twins), so the antibody protein that the identical cells make will also be identical. Solanezumab initially disappointed in the slowing of the progression of Alzheimer’s in patients with mild-to-moderate symptoms.

In 2010, another Lilly trial using investigational drug semagacestat for Alzheimer’s was halted, after patients’ conditions got worse and researchers linked it to a higher risk of developing skin cancer.

There are 7.7 million new diagnoses of dementia annually worldwide, approximately one every four seconds. Different estimates have calculated that between 2% and 10% of all dementia onsets begin before the patient is 65 years old.

Old and advancing age is the main risk factor for Alzheimer’s. Age-specific prevalence nearly doubles every five years after the age of 65. In 2010, industry analysts estimated that dementia’s global costs were $601 billion.

Written by Christian Nordqvist