Eisai and Biogen have had confirmation from US regulators that they can progress their BACE inhibitor E2609 into Phase III clinical trials to test its safety and efficacy in Alzheimer's disease.

Based on clinical and preclinical findings the US Food and Drug Administration has confirmed that there is sufficient data to start late-stage testing. The firms said they now intend to talk to regulators in Japan and Europe with the view to conducting the study globally, starting within the financial year 2016.

The study protocol will be a placebo-controlled design in patients with early Alzheimer's disease where the treatment group will be administered a dosage of 50 mg/day of E2609 with the primary outcome endpoint assessed at 24 months. The primary endpoint will be the Clinical Dementia Rating Sum of Boxes (CDR-SB), with routine safety assessment.

E2609 is believed to inhibit beta-secretase cleaving enzyme (BACE), a key enzyme in the production of amyloid beta. By inhibiting BACE, E2609 decreases amyloid beta proteins in the brain, potentially improving symptoms and slowing disease progression.

Eisai says data from the Phase II trial Study 202, in which the drug was dosed at 5mg, 15mg and 50mg per day in patients with early to moderate Alzheimer's disease, showed amyloid beta levels in the plasma and cerebrospinal fluid were reduced in a dose-dependent manner.