Post hoc analysis of the improvement in shoulder spasticity and safety observed following treatment with incobotulinumtoxinA

The Titration study in lOWer and uppER-limb spasticity (TOWER) study (NCT01603459), evaluated incobotulinumtoxinA for upper- and lower-limb spasticity. This post hoc analysis assessed shoulder spasticity in patients who received injections into the shoulder. Subjects received 3 injection cycles with escalating incobotulinumtoxinA doses on the same side (400, 600, 600-800 U; ≤ 600 U per limb including optional shoulder dose, planned range 100-250 U). Joint function was assessed with the Ashworth Scale shoulder sumscore (AS-SSS) in subjects treated in the shoulder vs those who were not. Safety was assessed in subjects treated in the shoulder, and in those who had upper-limb treatment without shoulder treatment. The proportion of subjects receiving shoulder treatment increased with escalating dose at each cycle (n = 84/140 (60.0%) by cycle 3; mean (standard deviation (SD)) shoulder dose 118.4 U (SD 60.2)). From baseline to 4-weeks post-injection, mean AS-SSS improved by -1.1 (SD 1.9), -1.7 (SD 1.8) and -1.7 (1.8) in cycles 1, 2 and 3, respectively, in subjects treated in the shoulder, and -0.5 (SD 1.3), -0.8 (SD 1.6) and -0.9 (SD 1.4) in subjects who were not. A significant dose effect on AS-SSS was observed in cycle 3 (p = 0.0081). No unexpected safety concerns were reported. The results demonstrate an improvement in shoulder spasticity and safety following incobotulinumtoxinA treatment.