Study	Reason for exclusion
AN072‐008 1995	This is a randomised, multicentre (USA), double‐blind, placebo‐controlled, single dose, four‐arm, dose‐finding parallel group design study. The follow‐up was 16 weeks. 85 participants were enrolled. Mean age was 53.2 years (18‐80). 38% of the participants were male and 62% were female. 95% were White. The study included both BtA‐responsive and ‐non‐responsive participants. The study drug (BtB) was provided by Athenas Neurociences, Inc. Each participant was randomly assigned to one of the 4 groups: placebo, 400 U, 1200 U or 2400 U of BtB. The study drug was injected into 2 to 4 superficial neck and/or shoulder muscle groups. Each participant received only one treatment. The primary efficacy outcome was the change in TWSTRS‐Total score (range 0 to 87). One participant in the placebo group withdrew because of an adverse effect. This study was excluded because data was not available
Chinnapongse 2010	This trial was a sequential dose‐escalation, safety, and tolerability study of BtB in subjects with cervical dystonia. Participants were assigned to one of three doses of BtB: 10,000 U, 12,500 U, and 15,000 U. Efficacy was evaluated using TWSTRS total and subscale scores and three VAS. The study was excluded for being open‐label and not having a placebo group
Cullis 2000	145 participants with cervical dystonia were enrolled. The study was open‐label and compared three different doses of BtB without a placebo group
Dressler 2005	This was a non‐randomised, non‐controlled study enrolling 9 participants with cervical dystonia aiming to test the immunogenicity of botulinum toxin type B in patients naïve to botulinum toxin treatment
Jacob 2003	This was a double‐blind study evaluating botulinum toxin type B diluted with preserved versus nonpreserved isotonic saline. Ten participants were treated on each half of the frontalis muscle with a total of 2400 units of botulinum toxin type B diluted either with preserved or nonpreserved saline. In addition to studying a different population, the study is not placebo‐controlled as both arms are treated with BtB
Jankovic 2006	This was a non‐randomised, non‐controlled, multicenter study enrolling 100 participants with cervical dystonia aiming to test the immunogenicity of botulinum toxin type B
Lew 2002	This paper describes an analysis of a subset of efficacy data from two randomised, double blind, placebo‐controlled clinical trials already included in this systematic review (Brashear 1999; Brin 1999)
Truong 1997	12 participants with cervical dystonia were enrolled. The study was open‐label and compared different doses of BtB without a placebo group