Eisai, Biogen's lecanemab cognitive improvement bodes well for Alzheimer's approval
travellinglight

Top-line phase 3 data from Eisai (OTCPK:ESALY) and Biogen (NASDAQ:BIIB) Alzheimer's candidate lecanemab that showed the improvement in clinical decline increased over time could help seal its approval by the US FDA.
Lecanemab was found to cut the cognitive and functional decline of patients with early stage of the disease by 27% compared to placebo over 18 months. This was based on the Clinical Dementia Rating scale sum of boxes (CDR-SB), the primary endpoint, a scale that assesses the severity of a wide range of stages of dementia.
But even more striking was that the improvement was seen as little as six months after treatment began and the effect grew with time. Lecanemab is given via infusion twice a month.
That's significant given that other Alzheimer's therapies have done well initially in terms of cognitive improvement only to taper off if not decline over time.
Both companies' stocks have surged Wednesday morning on the news. Biogen is up 38%, while Eisai (OTCPK:ESALY) is up 62%.
In a conference call this morning, Eisai (OTCPK:ESALY) also said results indicated that lecanemab demonstrated a disease-modifying effect.
Results also showed that clinical decline of cognitive function (ADAS-Cog14) was also reduced at an early stage. 
One potential cause for concern, however, was the incidence of a type of brain bleeding and swelling that is often present with anti-amyloid antibodies. In the treatment group, the rate of ARIA was 21.3% compared to 9.3% in the placebo group. The companies said this figure was "within expectations."
But it may not necessarily be smooth sailing for FDA approval for lecanemab given Biogen (BIIB) and Eisai's (OTCPK:ESALY) history with its other Alzheimer's drug, Aduhelm (aducanumab). While Aduhelm won FDA approval -- even though only one of two pivotal trials was successful -- in April, the Centers for Medicare & Medicaid Services (CMS) severely limited coverage of Aduhelm, essentially eliminating its market.
That decision also impacts other treatments that target amyloid plaque in the brain, which lecanemab does. It remains to be seen if CMS changes its policy on amyloid-targeting therapies. 
However, lecanemab has efficacy advantages over Aduhelm. While lecanemab slowed clinical decline by 27% compared to placebo, a similar aducanumab trial showed only 22% improvement. Also, the CDR-SB benefit was .45 points better with lecanemab against placebo compared to .39 points with aducanumab. 
The next steps for Biogen (BIIB) and Eisai (OTCPK:ESALY) for lecanemab are to formally present the data at the Clinical Trials on Alzheimer's Disease Conference in late November as well as in a medical journal.
The FDA has set Jan. 6, 2023 as a decision date for conditional approval of the candidate. The agency would base its decision on a smaller trial the companies conducted showing a reduction in amyloid plaque in the brain with treatment.
Eisai (OTCPK:ESALY) said the new data from the Clarity AD trial would be used for full approval in the US, Europe, and Japan by the end of the company's fiscal year, which is March 31, 2023.
But lecanemab has competition, namely from Roche (OTCQX:RHHBY) and Eli Lilly (LLY). Roche (OTCQX:RHHBF) is slated to present phase 3 data on gantenerumab in early Alzheimer's in Q4, while Lilly (LLY) will have phase 3 data on donanemab in mid-2023.