Skip to content

Aducanumab is an investigational drug and is not approved for use in the U.S. or any other country.

Aducanumab Principal Investigators

Thank you for your support of the development of aducanumab. We understand that you may have many questions. We will try to answer them below.

  1. Does Biogen see a correlation between the amount of amyloid that was removed and the degree of clinical benefit?
    1. The results of the new analysis of the larger dataset demonstrate a time- and dose-dependent reduction of amyloid plaque and a slowing of clinical decline as measured by the pre-specified primary and secondary endpoints.
    2. This is technically not a correlation analysis.
  2. What is the study design of the re-dosing study?
    1. The trial’s primary objective is to evaluate the long-term safety and tolerability of aducanumab. The primary outcome measures are: number of participants with Adverse Events (AEs) and Serious Adverse Events (SAEs); number of participants with AEs to treatment discontinuation or trial withdrawal; number of patients with ARIA-E or ARIA-H; and number of patients with anti-aducanumab antibodies in serum.
    2. We have aimed to make the eligibility criteria as inclusive as possible, in line with study requirements. The trial will offer access to aducanumab to eligible patients actively enrolled in the aducanumab studies in March 2019, including the aducanumab Phase 3 studies (ENGAGE & EMERGE), the long-term extension study for the Phase 1b PRIME study and the EVOLVE safety study. For example, there are no minimum or maximum age limits for inclusion in the trial. There will not be the need to be above any threshold on cognitive tests. The study will be an open-label, single-arm longitudinal study, with all participants receiving aducanumab – including prior placebo arm participants.
    3. As with any clinical study research protocol, there are inclusion and exclusion criteria that must be met to ensure participants are safe and able to fulfill all the protocol requirements.
    4. More details are now available at
  3. Why did Biogen do a futility analysis?
    1. Futility analyses are common in large clinical studies and these analyses help ensure that patients are not unnecessarily exposed to investigational therapies that are unlikely to be effective.
    2. They use statistical modeling to attempt to predict the outcome of the studies based on a number of pre-specified assumptions and criteria. There are multiple methodologies that can be used for futility analyses, and the methodology we used is a well-accepted approach.
  4. What did Biogen present at the 12th Clinical Trials on Alzheimer’s Disease (CTAD)?
    1. On December 5, 2019, Biogen presented additional details from EMERGE and ENGAGE, two global Phase 3 studies for aducanumab at the 12th Clinical Trials on Alzheimer’s Disease (CTAD) Congress in San Diego, CA. During this presentation, Biogen shared the topline data on the primary and secondary clinical endpoints based on the pre-specified statistical analysis plan, as well as data from disease biomarker sub-studies, including amyloid PET, tau PET and tau CSF biomarkers. Furthermore, we presented patient demographic characteristics and safety results from each study. LEARN MORE
  5. When will I hear more?
    1. We are now moving forward on the ground of positive clinical results, in consultation with the FDA, with a sense of urgency as we feel a deep responsibility to bring this potential treatment to patients as soon as possible.