- New data from the RESPOND study show that neurofilament levels, an indicator of neurodegeneration, were reduced in nearly all study participants treated with SPINRAZA
- Reductions in biomarker complement previously reported RESPOND efficacy results showing improved motor function in most participants treated with SPINRAZA after gene therapy
Today Biogen, Inc. announced interim 6-month biomarker data from the initial 29 participants in the open-label RESPOND study.* The Phase 4 study evaluates clinical outcomes and safety following treatment with SPINRAZA over a 2-year period in infants and toddlers with spinal muscular atrophy (SMA) who have unmet clinical needs after treatment with Zolgensma® (onasemnogene abeparvovec). The new data show that plasma neurofilament light chain (NfL) levels, an objective biomarker of axonal injury and neurodegeneration, were reduced in nearly all study participants treated with SPINRAZA.
NfL data from study participants treated with SPINRAZA for 6 months show:
Among participants with 2 SMN2 copies:
- All participants had elevated baseline NfL levels relative to healthy children of similar age
- In infants (n=11) who were 9 months or younger at first SPINRAZA dose (mean baseline NfL: 148.3 pg/mL), NfL levels decreased by a mean of 70% from baseline.
- In children (n=11) over 9 months of age at first SPINRAZA dose (mean baseline NfL: 121.8 pg/mL), NfL levels decreased by a mean of 78% from baseline.
Among participants with 3 SMN2 copies:
- Baseline NfL levels were elevated in 2 of 3 children (mean: 60.6 pg/mL).
- NfL reductions were observed in those with elevated levels at baseline and remained stable in the participant without an elevated level at baseline.
As reported at the SMA Research & Clinical Care Meeting in June 2023 from the same 29 participants, improvements in motor function were observed in most participants as measured by increased mean total Hammersmith Infant Neurological Examination Section 2 (HINE-2) score from baseline.1 No new emerging safety concerns have been identified in enrolled RESPOND participants who received SPINRAZA after Zolgensma. After a median of 230.5 days in the study, serious adverse events (AEs) were reported in 13/38 (34%) participants. Any AEs were reported in 31/38 (81.6%) participants. No serious AEs were considered related to SPINRAZA or led to study withdrawal, although some were related to administration.
*Clinical outcomes and NfL were analyzed in the 29 participants who had the opportunity for at least six months of treatment at the time of the interim analysis. Analysis of mean change in NfL includes participants with baseline and Day 183 assessments; a mean change from baseline was not reported in the 3 SMN2 copies group, due to the small number of participants. Safety data are reported in all participants (n=38) who received at least one dose of SPINRAZA in the trial.