Biogen/EisaiEisai and Biogen (Nasdaq:BIIB) today announced positive topline data from a Phase 3 trial of lecanemab for Alzheimer’s disease.

BIIB shares are skyrocketing on the back of the data today. They are up 37.6% at $272.12 apiece in mid-afternoon trading.

Lecanemab is an investigational anti-amyloid beta (Aβ) protofibril antibody. The global Phase 3 confirmatory Clarity AD clinical trial evaluated it for treating mild cognitive impairment (MCI) due to Alzheimer’s disease (AD) and mild AD (collectively known as early AD) with confirmed presence of amyloid pathology in the brain.

The drug met its primary endpoint and all key secondary endpoints with what the companies called “highly statistically significant results.” Eisai plans to discuss the data with regulatory authorities in the U.S., Japan and Europe. The company aims to file for traditional U.S. approval and authorization in Japan and Europe by the end of fiscal 2022 (March 31, 2023).

Additionally, Eisai intends to present the study data on November 29, 2022, at the Clinical Trials on Alzheimer’s Congress (CTAD) and publish the findings in a peer-reviewed medical journal.

Clarity AD evaluated 1,795 people with early AD in a placebo-controlled, double-blind, parallel-group format. The treatment group received 10 mg/kg bi-weekly of lecanemab, with participants allocated in a 1:1 ratio to receive either placebo or lecanemab. Eisai’s recruitment strategy aimed at better inclusion of ethnic and racial populations in the U.S., too. The company said approximately 25% of the total U.S. enrollment included Hispanic and African American persons.

The primary endpoint for the study was CDR-SB (Clinical Dementia Rating-Sum of Boxes) — a numeric scale for quantifying the severity of symptoms of dementia. Lecanemab met the endpoint and reduced clinical decline on the CDR-SB global cognitive and functional scale compared with placeby by 27% at 18 months.

As early as six months in, the treatment demonstrated statistically significant changes in SDR-SB from baseline compared to placebo.

Key secondary endpoints were change from baseline at 18 months compared with placebo of treatment in amyloid levels in the brain measured by amyloid positron emission tomography (PET), the AD Assessment Scale-cognitive subscale14 (ADAS-cog14), AD Composite Score (ADCOMS) and the AD Cooperative Study-Activities of Daily Living Scale for Mild Cognitive Impairment (ADCS MCI-ADL). The trial met all key secondary endpoints.

“The positive result of the lecanemab, an anti-Aβ protofibril antibody, pivotal study after almost 25 years since Aricept’s launch is an important milestone for Eisai in fulfilling our mission to meet the expectations of the Alzheimer’s disease community. Alzheimer’s disease not only presents a great challenge for patients and their families, but it also negatively impacts society, including decreased productivity, increased social costs and disease-related anxiety. We believe that helping to alleviate these burdens will positively impact society as a whole,” said Haruo Naito, CEO at Eisai. “Additionally, the lecanemab Clarity AD study results prove the amyloid hypothesis, in which the abnormal accumulation of Aβ in the brain is one of the main causes of Alzheimer’s disease, when targeted with a protofibril-binding therapy. Eisai believes these findings will create new horizons in the diagnosis and treatment of Alzheimer’s disease as well as further activate innovation for new treatment options.”

Biogen CEO Michel Vounatsos added that the data announcement “gives patients and their families hope” that, if approved, lecanemab can slow the progression of AD.

“Importantly, the study shows that removal of aggregated amyloid beta in the brain is associated with a slowing of disease in patients at the early stage of the disease,” said Vounatsos.

In July, the FDA accepted Eisai’s Biologics License Application (BLA) for lecanemab under the accelerated approval pathway and granted Priority Review. Results of Clarity AD can serve as the confirmatory study to verify the clinical benefit of lecanemab. The Prescription Drugs User Fee Act action date (PDUFA) is January 6, 2023.

Eisai added that it submitted the BLA through the accelerated approval pathway so the agency could complete its review with the exception fo the data from the confirmatory study in an effort to secure traditional approval as soon as possible.

GlobalData Senior Neurology Analyst Pippa Salter wrote in a report that, while the companies’ Aduhelm will have first-to-market advantage, GlobalData expects lecanemab to be “significantly more successful” on the back of the data reported today.

“After multiple failures, and the controversial approval and messy launch of Biogen’s anti-Aβ mAb Aduhelm (aducanumab), lecanemab has finally demonstrated in a large-scale pivotal trial that targeting Aβ can be a successful way to treat AD,” said Salter. “The primary endpoint that lecanemab met in the trial demonstrates that the drug is specifically effective for reducing cognitive decline. This is particularly important to lecanemab’s prospects, as it demonstrates that it has a significant clinical effect, unlike Aduhelm which failed to demonstrate this in its own clinical trials and was approved based on the surrogate endpoint of Aβ clearance.