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Page last checked: 29th November 2022
Last updated: 9th February 2022


This 26th January 2022 answer is on the NICE website.

What are the clinical circumstances under which it would be possible to switch from treatment with nusinersen to risdiplam or from risdiplam to nusinersen? Under what circumstances would it be possible to switch back to the original treatment?


In order to answer this question, it is important to explain how MAAs work.

Both nusinersen and risdiplam are only available under Managed Access Arrangements (MAAs). An MAA is put in place when a medicine shows promising potential but there is significant uncertainty in the longer-term clinical evidence. MAAs provide a way for patients to receive promising new treatments, while further evidence is collected to assess the long-term benefits of a new medicine.

Based on the evidence available when NICE made its decisions about recommending risdiplam and nusinersen, the long-term benefits for patients were still very uncertain. The MAAs have been designed to allow enough time for additional evidence to be generated for NICE.

At the end of the MAA period, NICE will review the new evidence and review its guidance to indicate whether the medicine should be recommended to use in the NHS – this may result in a difference to what the NHS will pay for the drug for example. While most topics recommended for managed access go on to be recommended for routine use on the NHS, there is no guarantee that it will be recommended when it is reviewed by NICE.

If patients switch between nusinersen and risdiplam, it is likely to be difficult and may not be possible to collect reliable evidence relating to the impact of each individual treatment., As a result, it is possible that the evidence generated under the MAA is insufficient to enable NICE to recommend one or both drugs for use on the NHS.

Patients and families should consider very carefully with their treating clinician whether there is a clinical reason to switch from one treatment (treatment A) to another (treatment B), as switching back to treatment A is only likely to be advisable if:

  • treatment B is causing side effects that preclude the administration of treatment B and/or


  • there is demonstrable deterioration in motor or respiratory function following the switch to treatment B.

It is recommended that treating clinicians seek advice from the NHS England SMA Clinical Panel in the event that there may be a case for switching back to treatment A.

Given the complex nature of decisions around treatment switching, all discussions must take place face-to-face between the patient / family and their treating clinician.

Where a switch between treatments is necessary, there should be a gap of four months between stopping treatment with nusinersen and starting treatment with risdiplam and a gap of 15 days between stopping treatment with risdiplam and starting treatment with nusinersen (this may be shortened exceptionally). It may be necessary for nusinersen loading doses to be administered again, if a patient switches from nusinersen to risdiplam and then switches back again.