New data from the long-term extension phase of two phase 3 trials evaluating aducanumab-avwa in early Alzheimer disease showed that patients continued to experience significant reductions in amyloid beta plaques and plasma p-tau181.

The randomized, double-blind, placebo-controlled, global, EMERGE ( Identifier: NCT02484547) and ENGAGE ( Identifier: NCT02477800) trials evaluated the efficacy and safety of aducanumab-avwa, an amyloid beta-directed antibody, in a total of 3285 adults aged 50 to 85 years with early Alzheimer disease. In June 2021, the Food and Drug Administration (FDA) granted accelerated approval to aducanumab-avwa (marketed under the brand name Aduhelm®) for the treatment of Alzheimer disease based on 78-week data from both trials.

Data from the long-term extension study showed that continued treatment with aducanumab-avwa significantly reduced amyloid beta plaque levels out to week 132, and continued to decrease plasma p-tau181 levels at week 128. Moreover, patients who experienced more effective amyloid beta clearance (standardized uptake value ratio [SUVR] lower than 1.1 by 78 weeks) had greater reductions in p-tau181 at week 128.

In both studies, there was a positive correlation between plasma p-tau181 reduction and less clinical decline in all 4 clinical outcome measures of cognition and function at week 78 including Clinical Dementia Rating Sum of Boxes Score (CDR-SB), Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale–Cognitive Subscale (ADAS-Cog 13), and Alzheimer Disease Cooperative Study/Activities of Daily Living scale adapted for MCI (ADCS-ADL-MCI). 

“These are meaningful findings, which further our understanding of amyloid and downstream biomarkers, such as p-tau181, in Alzheimer disease and can help inform how long patients may benefit from treatment to reduce amyloid beta plaque,” said Samantha Budd Haeberlein, PhD, SVP, Head of Neurodegeneration Development at Biogen. “These data demonstrate that long-term treatment with Aduhelm continues to reduce the underlying pathologies of Alzheimer disease beyond 2 years.”


  1. Long-term phase 3 data show Aduhelm® continues to reduce underlying pathologies of Alzheimer’s disease in patients treated for more than two years. News release. Biogen Inc. Accessed March 16, 2022. 
  2. Biogen announces peer-reviewed publication of Aduhelm® phase 3 EMERGE and ENGAGE data in the journal of prevention of Alzheimer’s disease. News release. Biogen Inc. Accessed March 16, 2022.