In the partnership that spawned aducanumab, Eisai Co Ltd (OTC:ESALY) and Biogen Inc (NASDAQ:BIIB) have released more data on lecanemab, another anti-Alzheimer's drug. 

• The lecanemab's Phase 2b study data were presented at the annual AD/PD meeting.
• The ratio of amyloid-related imaging abnormality (ARIA) in the Core study was 9.9% (16/161) of patients treated with the drug's 10 mg/kg dose biweekly, compared with 0.8% (2/245) of placebo patients.
• Over 40% of approximately 12 treatment-naïve patients in the open-label extension (OLE) were amyloid negative as early as three months. More than 80% were amyloid negative by 12 months. 
• Related: Eisai Posts New Lecanemab Data From Mid-Stage Alzheimer's Trial.
• The OLE results are consistent with core phase results in which 65% were amyloid negative at 12 months, and 81% of participants were amyloid negative at 18 months in 161 subjects treated with 10 mg/kg biweekly dose. 
• Robust amyloid reduction in those receiving lecanemab in the Core study was maintained while off-treatment over the Gap period. 
• Lecanemab is in the middle of a Phase 3 trial, expected to have a readout sometime this fall.
• Price Action: BIIB shares are up 2.07% at $211.10 during the market session on the last check Tuesday.