The primary objective of this study was to assess subject-centered, function-related goal attainment (Goal Attainment Scale T-Score) after multiple/repeated abobotulinumtoxinA injections in pediatric patients with lower limb spasticity. Effectiveness of abobotulinumtoxinA in injected muscle groups via the Modified Ashworth Scale (MAS) was also assessed.

AbobotulinumtoxinA is approved for treatment of pediatric lower limb spasticity (PLLS). Treatment and goals need to be individualized according to patient needs.

This phase IV study (NCT03017729) was designed to collect real-world data on the clinical use of abobotulinumtoxinA for the treatment of PLLS (aged 2–17 years). Prescription decision was made prior to, and independent from, study enrollment, with abobotulinumtoxinA used according to local prescribing information. Functional goals (utilizing the T-score) were identified at baseline by patient/parent/caregiver in consultation with investigators. Muscle tone was assessed using the MAS at baseline and at subsequent visits. Adverse events were collected throughout the study.

Of 144 patients who had their second injection and were included in this first interim analysis, 76.4% (n=110) were botulinum neurotoxin (BoNT)?non-naïve. At time of enrollment, 76.4% were aged 2–9 years. At the end of treatment cycle 1, mean T-score (SD) for the total population was 52.41 (11.76); BoNT-naïve (N=34) was 53.59 (13.63) versus BoNT?non-naïve 52.05 (11.16). In patients aged 2–9 years, T-score was 51.78 (11.01) versus 54.46 (13.88) in patients aged 10–17 years. MAS responses (≥1 point reduction from baseline) were similarly observed in gastrocnemius (29.9%, n=23/77), soleus (22.0%, n=9/41), and hamstrings (21.6%, n=8/37), but less frequently in adductors (4.8% 1/21).

Goal attainment outcomes were better than expected (T-score >50.0) for the overall PLLS population as well as for BoNT-naïve/non-naïve patients and both age subgroups. Injected muscles demonstrated tone reduction via MAS evaluations. Safety data will be presented at next interim analysis.