Efficacy of incobotulinumtoxinA for the treatment of adult lower-limb post-stroke spasticity, including pes equinovarus

Abstract

Background: Lower-limb spasticity can impair ambulation and gait, impacting quality of life.

Objectives: This ancillary analysis of the TOWER study (NCT01603459) assessed the efficacy of incobotulinumtoxinA for lower-limb post-stroke spasticity including pes equinovarus.

Methods: Participants received escalating incobotulinumtoxinA doses (400-800U) across 3 injection cycles. Changes were compared for those treated in the lower limb (with/without upper-limb treatment) or the upper limb only or for participants treated or untreated for pes equinovarus. Outcome measures were those used in the seminal study: resistance to passive movement scale (REPAS), Ashworth Scale (AS), functional ambulation and lower-limb goal attainment.

Results: Among 132/155 (85%) participants with post-stroke spasticity, in cycles 1, 2 and 3, 99, 119 and 121 participants received lower-limb treatment with mean (SD) total limb incobotulinumtoxinA doses of 189.2 (99.2), 257.1 (115.0) and 321.3 (129.2) U, respectively. Of these, 80, 105 and 107, respectively, were treated for pes equinovarus. The mean (SD) improvement in REPAS lower-limb score was greater with treatment in the lower limb versus the upper limb only: -1.6 (2.1) versus-0.4 (1.4); -1.9 (1.9) versus -0.6 (1.6); -2.2 (2.2) versus -1.0 (0.0) (P=0.0005, P=0.0133 and P=0.3581; analysis of covariance [ANCOVA], between-group differences) in cycles 1, 2 and 3, respectively. For all cycles, the mean improvement in ankle joint AS score from injection to 4 weeks post-treatment was greater for participants treated versus not treated for pes equinovarus, with a significant between-group difference in cycle 1 (P=0.0099; ANCOVA). At the end of cycle 3, 42% of participants walked independently and 63% achieved 2 of 2 lower-limb treatment goals (baseline 23% and 34%, respectively).

Conclusions: This study supports the efficacy of incobotulinumtoxinA for treatment of pes equinovarus and other patterns of lower-limb post-stroke spasticity.

Keywords: Botulinum neurotoxin; IncobotulinumtoxinA; Lower limb; Pes equinovarus; Rehabilitation; Spasticity.