Effects of repeated abobotulinumtoxinA injections in upper limb spasticity

Abstract

Introduction: The efficacy of single injections of abobotulinumtoxinA (Dysport) is established in adults with upper limb spasticity. In this study we assessed the effects of repeated injections of abobotulinumtoxinA over 1 year.

Methods: Patients (n = 258, safety population) received 500 U, 1,000 U, or 1,500 U (1,500-U dose included 500-U shoulder injections) for up to 4 or 5 treatment cycles. Assessments included treatment-emergent adverse events (TEAEs), muscle tone, passive and active range of motion (X_V1, X_A ), angle of catch (X_V3 ), Disability Assessment Scale (DAS) score, Modified Frenchay Scale (MFS) score, and Physician Global Assessment (PGA) score.

Results: The incidence of TEAEs decreased across cycles. Muscle tone reduction and X_V1 remained stable across cycles, whereas X_V3 and X_A continued to improve at the finger, wrist, and elbow flexors. DAS and PGA improved across cycles. MFS improved best with 1,500 U.

Discussion: A favorable safety profile and continuous improvements in active movements and perceived and active function were associated with repeated abobotulinumtoxinA injections in upper limb muscles. Muscle Nerve 57: 245-254, 2018.

Keywords: active function; botulinum toxin; open label; stroke; traumatic brain injury; upper limb spasticity.

Figure 1

Disposition of patients. Differences in patient numbers between cycles due to patients entering the observational phase (OP) or ending the study after 12 months of follow‐up. Patients in the OP were followed up every 4 weeks until they required reinjection or completed 12 months of follow‐up. ^aIndicates newly recruited patients only. UL, upper limb; LL, lower limb; AE (UTT), adverse event (unrelated to treatment); WD, withdrawn.

Figure 2

Passive range of motion (X_V1), angle of catch (X_V3), and active range of motion (X_A) at baseline and week 4 of each cycle in each primary target muscle group for all patients and all doses pooled. Values are presented as mean (standard deviation). BSL, baseline of double‐blind study; DB, double‐blind.

Figure 3

Disability Assessment Scale responders for each domain by abobotulinumtoxinA dose at week 4 of each cycle. Data for 500 U are not presented for cycles 1–4 due to small patient numbers, which provide little statistical value. N values are presented in order of doses shown (500 U, 1,000 U, 1,500 U). DAS, Disability Assessment Scale; DB, double‐blind.

Figure 4

Mean change in Modified Frenchay Scale overall score by abobotulinumtoxinA dose at week 4 of each cycle. Values are presented as mean (standard deviation). Data for 500 U are not presented due to small patient numbers, which provide little statistical value. N values are presented as those for 1,000 U and 1,500 U. The dotted line indicates change from baseline to cycle 2 for 1,500 U, as patients could not receive this dose in the DB study and at cycle 1. BSL, baseline of DB study; DB, double‐blind; MFS, Modified Frenchay Scale.