Eisai Co. Ltd. and Biogen Inc. said their experimental Alzheimer's disease drug showed positive results in a final analysis of a mid-stage study.
An earlier 12-month analysis of the same study had failed to meet the criteria for success, the companies said in December 2017.
Topline results released July 5 from the phase 2 trial, called Study 201, showed that cognitive abilities of Alzheimer's patients receiving the highest dose of the medicine BAN2401 declined more slowly than those taking a placebo.
Full results of the trial which lasted 18 months will be released at future academic conferences, Biogen and Eisai said in the release.
BAN2401 works by binding to and clearing beta-amyloid — abnormal proteins that accumulate in the brain of patients with Alzheimer's disease. So far, researchers focusing on this area have failed to find a strong correlation between the severity of the disease and amount of beta-amyloid accumulation.
"This is the first late-stage anti-amyloid antibody study to successfully achieve statistically significant results at 18 months, further validating the amyloid hypothesis," said Lynn Kramer, chief clinical officer and chief medical officer at Eisai's neurology unit, said in a news release.
Study 201 enrolled 856 patients showing early onset of Alzheimer's with three groups getting biweekly BAN2401 doses of 2.5, 5 or 10 miligrams; two groups getting monthly BAN2401 doses of 5 or 10 mg; and one group receiving placebo.
Additionally, patients who received the highest dose of BAN2401 saw statistically significant clinical benefit as early as six months into the trial. At 18 months, BAN2401 proved most effective in the group receiving the biweekly 10 mg dose. The disease progressed more slowly and there was a reduction in the accumulated amyloid in the group.
The drug was well tolerated with mostly mild to moderate adverse reactions seen.
"We will discuss these very encouraging results with regulatory authorities to determine the best path forward," said Kramer.
The companies did not give any details about their plans for advancing the study into phase 3, which is the final stage of testing before the drug can be approved for market.
The study had not achieved its primary outcome measure based on the analysis at 12 months of treatment which would have helped it gain a more rapid entry into phase 3 development, the release said. Many Alzheimer's drugs which have moved to the phase 3 stage have failed or were pulled out of the late trials — for example Eli Lilly and Co. and AstraZeneca PLC's experimental drug lanabecestat.
Aside from BAN2401, Eisai and Biogen are also collaborating on two other drugs to treat the disease that has long stumped researchers and drug developers. Aducanumab and E2609, or elenbecestat, are among the top drugs for Alzheimer's in the global product pipeline, according to EvaluatePharma's 2022 consensus forecast, published in 2017.
Alzheimer's is the most common cause of dementia, which is characterized by the progressive loss of memory and other cognitive functions. While there is no cure for the disease yet, the pharmaceutical industry has struggled to get a drug to market, spending billions of dollars in failed trials in the process.