SMA Newsroom

Sep 17, 2021

Biogen to start new trial to evaluate higher doses of nusinersen in later-onset SMA

Biogen plans to initiate a new clinical trial called ASCEND, which will evaluate whether treatment with a higher dose of nusinersen has the potential to improve clinical outcomes and address unmet medical needs in people with later-onset SMA who were previously treated with risdiplam.

Study overview

The ASCEND study will assess if nusinersen at an investigational higher dose may address outstanding clinical needs among people with later-onset SMA, who were treated with risdiplam and want to make a change in their treatment regimen. This includes both adults who have been treated with nusinersen prior to risdiplam, as well as children, teens and adults who have only been treated with risdiplam and have not previously received nusinersen.

Study design

The ASCEND protocol has been submitted to regulatory authorities.

  • Time scale: ASCEND will last approximately 2.5 years
  • Participants:
    • Up to 135 later-onset, non-ambulatory (unable to walk independently) people with SMA aged 5-39 will be enrolled
    • All participants must have been treated with the maximum dose of 5 mg of risdiplam before joining the study, and be willing and able to change their treatment regimen to a higher dose of nusinersen
    • Further eligibility criteria also apply.
  • Doses: All participants will receive 2 initial nusinersen doses of 50mg two weeks apart, followed by a maintenance dose of 28mg every 4 months over the remaining study period. The 50 mg and 28 mg doses of nusinersen are not approved doses and are higher than the currently approved 12mg nusinersen dose. These higher doses are also being evaluated in the DEVOTE study.

Patient outcomes

In this study, efficacy is planned to be assessed using a motor function tool called the Revised Upper Limb Module (RULM). Additional clinical outcomes include safety, motor function using the Hammersmith Functional Motor Scale Expanded (HFMSE) and caregiver burden. A protein found in neurons called neurofilament, will be explored as a biological marker of disease activity. In participants aged 13 years and older, upper limb fine motor function will also be assessed using a mobile application.


The first eligible participants are expected be enrolled in the ASCEND study later in 2021. Further information on the study will soon be available on

Working in partnership

A consultation process with the SMA community has been conducted in order to shape the design of this study and ensure that the clinical outcome measures being used are those that matter most to people living with SMA.