A single dose was shown to stop SMA progression and improve motor function

The ITVISMA clinical study measured outcomes up to 52 weeks.

Results in people with no prior treatment

The main study that evaluated ITVISMA was called the STEER study. The purpose of this study was to establish the efficacy and safety of ITVISMA in people with SMA, aged 2 to 17 years old, who had never been on SMA treatment. 126 people participated in the study. 75 of these participants were given ITVISMA, and 51 were part of a sham-control group (which means no drug was injected). All 126 participants were able to sit but never able to walk independently.

Efficacy was based on the change in baseline Hammersmith Functional Motor Scale - Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores at ~1 year.

Secondary result from the STEER study:

We cannot make conclusions from the following data. They are presented for observational purposes.*

•    People also saw a 2.44-point increase in their RULM score, a scale used to measure the strength and function of their hands and arms (vs a 0.92-point change in the sham-control group)

*These endpoints did not meet statistical significance as outlined in the study.
 

Results in people who stopped their previous treatment and started ITVISMA

There was also a supporting clinical study called the STRENGTH study. The STRENGTH study was an open-label study with no comparator group. This means that in this study all participants received ITVISMA, and participants and doctors both knew what treatment was being given. The results of this type of study could be influenced by the expectations of the patients and doctors. We cannot make conclusions from the following data.

The purpose of this study was to establish the safety and efficacy of ITVISMA in people with SMA, aged 2 to 18 years old, who had previously taken SPINRAZA^® (nusinersen) or EVRYSDI^® (risdiplam) and stopped those treatments. Before receiving ITVISMA, people in the study had been treated with other SMA therapies for several years—the study included people who received at least 4 loading doses of nusinersen or 3 months of risdiplam. All 27 participants were able to sit but not able to walk independently.

Efficacy was a secondary endpoint and was measured using the change from baseline in Hammersmith Functional Motor Scale – Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores at the end of the 52-week study.

About HFMSE and RULM scores 

Hammersmith Functional Motor Scale – Expanded (HFMSE) Assesses 33 activities including sitting, standing, and climbing stairs.  Each activity is graded from 0 (unable or less able to perform action) to 2 (able to perform action).  The total possible score is 66; a higher score means greater motor function.  On the HFMSE scale, a 1- to 2-point increase is considered a positive change. An improvement of ≥3 points is a clinically meaningful change.

Revised Upper Limb Module (RULM) Assesses 19 activities that involve the hands and arms, such as picking up or placing small items and pressing buttons. 18 of the 19 activities are graded from 0 (unable or less able to perform action) to 2 (able to perform action); 1 activity is scored on a scale from 0 (unable to perform action) to 1 (able to perform action).  The total score ranges from 0 to 37; a higher score means greater motor function.