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Page last updated: 11th March 2024

Biogen recently announced interim 6-month data from the RESPOND Trial of Spinraza™ that indicates the treatment is able to reduce the levels of a key disease-indicator protein neurofilament.

Neurofilament (also known as neurofilament light chain, or NfL) is released into the blood when neurons degenerate or die, and can therefore be used to measure the progression of nervous system conditions, such as SMA. For this reason, neurofilament is known as a ‘blood biomarker’. As the nervous system becomes more affected and a condition gets worse, the amount of neurofilament that can be detected in blood increases. Similarly, if a treatment is able to reduce the effects of the condition, the amount of detectable neurofilament can be lower.

The RESPOND Trial is a phase 4 study evaluating the benefit of Spinraza™ in infants with SMA previously treated with Zolgensma™. Only those who have been determined by an investigator to have the potential for additional clinical improvement have been included in the trial.

Previously released preliminary data indicate that 24 participants with two copies of the SMN2 gene showed an average improvement of more than 5 points on the Hammersmith Infant Neurological Examination Section 2 (HINE-2) score, compared to their baseline score before treatment. Furthermore, all participants with three copies of SMN2 also showed improvements in HINE-2.

The latest reported data show that neurofilament levels in the blood were reduced in almost all participants treated with Spinraza™ for 6 months.

As expected, neurofilament at baseline was increased in almost all participants compared with unaffected children of a similar age. In Spinraza™-treated infants with two copies of SMN2, neurofilament levels decreased on average 70-80% from baseline. In those with three SMN2 copies, baseline levels were reduced in two out of the three participants. Spinraza treatment reduced neurofilament in those two patients and stabilised neurofilament in the participant without elevation at baseline.

These positive data support that Spinraza™ treatment after receiving Zolgensma™ is having a positive effect on the blood biomarker neurofilament, suggesting that the dual treatment approach can have added benefit in, at least some, people with SMA.

Biogen aim to recruit a total of 60 participants in the RESPOND trial, which has an estimated completion date of late 2024.


Further information:

Biogen Press Release >

Clinical Trial Page >

Previous Updates

 

2nd August:

Biogen recently announced the latest data from the RESPOND trial, which is a phase 4 study designed to assess the safety and efficacy of Spinraza (nusinersen) in infants and children up to age 3 years with SMA who are determined by the investigator to have the potential for additional clinical improvement following previous treatment with Zolgensma (onasemnogene abeparvovec).

In a presentation given at the 2023 SMA Research & Clinical Care in Florida, Biogen provided interim results showing that Spinraza treatment resulted in motor function gains in most participants.

Initiated in July 2020, RESPOND is an actively recruiting (not in the UK) two-year, open label study that seeks to understand if the increased and continuous production of SMN protein by nusinersen provides any additional benefits to patients previously treated with Zolgensma.

Motor function of treated individuals was assessed using the Hammersmith Infant Neurological Examination Section 2 (HINE-2) score. 24 participants with two copies of the SMN2 gene showed an average improvement of more than 5 points on HINE-2 compared to their baseline score before treatment. Furthermore, all participants with three copies of SMN2 also showed improvements in HINE-2 – however, the average change in score was not calculated due to only three participants in this category being included in the trial thus far.

In addition, no Spinraza-related safety concerns were reported, and no serious adverse events led to withdrawal from the study.

Biogen aim to recruit a total of 60 participants in the RESPOND trial, which has an estimated completion date of September 2024.

Biogen’s Press Release >


The study groups:

  1. The primary study group aims to include 40 infants aged 9 months or younger (at the time of first nusinersen dose), who have two copies of SMN2 (thus likely to develop SMA Type 1) and received SMN gene therapy (Zolgensma) at 6 months old or younger.
  2. The second study group will include 20 children and will generate data in patients with a broader age range (up to age 3 at the time of the first nusinersen dose). After a screening period, participants will receive the approved 12 mg dose of nusinersen administered intrathecally by lumbar puncture on Days 1, 15, 29, and 64 (loading doses), followed by a maintenance period during which the participants will receive 12 mg nusinersen intrathecally every 4 months for two years5.

RESPOND is a phase 4, open-label study, so both the patient’s caregiver and their physician are aware that they are being treated with nusinersen. The study will be conducted at approximately 20 sites worldwide.


1. Zolgensma EU Summary of Product Characteristics (SmPC). Available here. Accessed on Oct. 12, 2020.

2. Finkel R, et al. Presented at the Muscular Dystrophy Association’s (MDA) 2020 Clinical & Scientific Conference.

3. Harada Y, et al. Presented at the Muscular Dystrophy Association’s (MDA) 2020 Clinical & Scientific Conference.

4. Finkel R, et al. Presented at the World Muscle Society (WMS) 2020 Virtual Congress.

5. Spinraza U.S. Prescribing information available, here.

23rd June: Data presented by Biogen showed that all enrolled study participants reported suboptimal clinical status across a variety of measures at baseline, with 13 of 16 showing this in multiple areas, including motor and respiratory functions and swallowing / feeding ability.

After beginning Spinraza treatment, initial safety findings showed three participants experienced a serious adverse event during the study period; none of these events were considered related to Spinraza.

11th January: Biogen announces first child treated as part of the Respond study.

21st July: Biogen announces intention to initiate the RESPOND Study.