No difference in efficacy between Xeomin® and Botox® in the treatment of cervical dystonia – a detailed subgroup analysis

Introduction: Treatment of cervical dystonia (CD) with the highly purified Botulinum neurotoxin type A (BTX-A) free of complexing proteins (Xeomin) is mainly based on the largest controlled study of BTX-A ever performed (Benecke et al. 2005) demonstrating that Xeomin is non-inferior to Botox and that in average the efficacy of one Xeomin unit is equivalent to one Botox unit.

To support this dose ratio, we re-analysed the data of this study whether various subgroups of patients revealed a different response to Xeomin or Botox.

Results: The separate analysis of the TWSTRS – Severity score with regard to subgroups by age (<50 years vs. ≥50 years) and gender revealed a higher improvement of the score in the younger patients which was additionally slightly more pronounced in male than in female patients.

No difference between Xeomin or Botox could be detected. The change in the TWSTRS Severity score was higher in the low dose group (≤120 U) in comparison to the high dose group (>120 U): Xeomin: -6.6,-6.4, Botox®: -6.7, -6.0, respectively).

The percentage of non-responders (≤20% improvement) or “golden“ responders (>70% improvement) did not differ significantly in the individual severity subgroups. The treatment effect increases with higher baseline severity. No difference between Xeomin and Botox was found regardless whether mildly, moderately, or severely affected patients were treated.

Change in TWSTRS-Severity score after 4 weeks

Xeomin
TWSTRS Severity at baseline	N	Mean (SD)
Mild (<15)	58	-5.6 (3.3)
Moderate (16–21)	140	-6.6 (4.0)
Severe (>22)	32	-8.2 (5.0)
Botox
TWSTRS Severity at baseline
Mild (<15)	60	-5.1 (3.8)
Moderate (16–21)	127	-6.4 (3.7)
Severe (>22)	39	-8.1 (4.0)

Conclusions: In summary, the present detailed subgroups analysis between Xeomin or Botox did not reveal any statistically significant differences. Therefore no relevant difference in medical practice can be expected (as long as quality standards for Xeomin and Botox are kept constant).