The permanent J-code for ITVISMA^® is J3405, and goes into effect starting on July 1, 2026 for all sites of care.

Explore the clinical data. Scarlette lives with SMA and hasn't received ITVISMA. She was compensated for her time.

STRENGTH: supportive safety study in previously treated patients with SMA¹

STRENGTH study design

STRENGTH was an open-label, single-arm, multicenter, phase 3b, safety study with efficacy as a secondary endpoint in 27 patients with spinal muscular atrophy (SMA), aged 2 to <18 years, who discontinued previous SMA treatment and were able to sit independently* but have never taken steps independently.^1,†

*Independent sitting is defined as sitting up straight with the head erect for at least 10 seconds without using arms or hands to balance the body or support the position.¹
^†Previous SMA disease-modifying therapies (DMTs): risdiplam, n=4 (14.8%); nusinersen, n=21 (77.8%); nusinersen and risdiplam (non concurrently), n=2 (7.4%).¹

STRENGTH endpoints

STRENGTH enrollment criteria

Baseline demographics and characteristics

HFMSE score

HFMSE scores over 52 weeks with ITVISMA¹

Change from baseline to Week 52 in HFMSE total score for the overall study¹

Mean change from baseline in the HFMSE score with ITVISMA over a 52-week span.

Data are displayed as mean (SD) and LS mean (95% CI).¹

As a secondary endpoint, the mean (SD) change from baseline in Hammersmith Functional Motor Scale — Expanded (HFMSE) score at Week 52 was 0.17 (2.88) for patients treated with ITVISMA (n=21)¹
Additionally, as a secondary endpoint, the LS mean change from baseline in HFMSE score was 1.05 (95% CI: –0.21, 2.32) at Week 52, using the MMRM method (n=21)^1,‡

^‡Exploratory analyses used a mixed model with repeated measurement (MMRM) approach to calculate the LSMs.¹

RULM score

RULM score over 52 weeks with ITVISMA¹

Change from baseline to Week 52 in RULM total score for the overall study¹

Mean change from baseline in the RULM score with ITVISMA over a 52-week span.

Data are displayed as mean (SD) and LS mean (95% CI).¹

As a secondary endpoint, the mean (SD) change from baseline in RULM score at Week 52 was 0.29 (2.85) for ITVISMA (n=21)¹
Additionally, as an exploratory endpoint, the LS mean change from baseline in RULM score was 0.59 (95 % CI: -0.56, 1.73) at Week 52, using the MMRM method (n=21)¹

Some patients self-reported discontinuing previous SMA therapy¹

Of the 27 patients in STRENGTH, 6 patients (22.2%) self-reported at baseline that lack of efficacy was a reason to discontinue their previous SMA therapy.

Explore the pivotal trial in treatment-naive patients

See the data

AAV9, adeno-associated virus serotype 9; CI, confidence interval; HFMS, Hammersmith Functional Motor Scale; LS, least squares; LSM, least squares mean; SD, standard deviation; SMN1, survival motor neuron 1 gene; SMN2, survival motor neuron 2 gene.

Baseline demographics and characteristics¹
Characteristics	Total (N=27)
Age at symptom onset, years
Mean (SD)	0.8 (0.38)
Min–max	0.08–1.42
Age at diagnosis, years
Mean (SD)	1.0 (0.55)
Min–max	0.11–1.93
Age at ITVISMA dosing, years
Mean (SD)	7.4 (3.35)
Min–max	2.4–17.7
SMN2 copy number, n (%)
2	4 (14.8)
3	23 (85.2)
Sex, n (%)
Male	15 (55.6)
Female	12 (44.4)
Race, n (%)
White	13 (48.1)
Asian	6 (22.2)
Multiple	1 (3.7)
Not reported	7 (25.9)
Previous SMA DMTs, n (%)
Nusinersen	21 (77.8)
Risdiplam	4 (14.8)
Nusinersen and risdiplam (not concurrently)	2 (7.4)
Duration of nusinersen, years
n	23
Mean (SD)	4.3 (1.07)
Min–max	1.86–6.18
Duration of risdiplam, years
n	6
Mean (SD)	3.0 (2.02)
Min–max	0.39–6.28
HFMSE baseline score
Mean (SD)	24.3 (14.04)
Min–max	2.0–46.5
RULM baseline score
Mean (SD)	24.6 (7.44)
Min–max	7.5–36.0

STRENGTH: supportive safety study in previously treated patients with SMA¹