Lew M F, Brashear A, Factor S
University of Southern California School of Medicine, Los Angeles, 90033, USA.
Neurology. 2000;55(12 Suppl 5):S29-35.
Cervical dystonia (CD) is characterized by abnormal, involuntary contractions of the cervical and/or shoulder muscles. Direct injection of Botulinum toxin type A (BTX-A) into the affected muscles has been used successfully to treat this condition. However, clinical resistance to BTX-A therapy develops in a limited number of patients. Moreover, an unknown proportion of treated patients have a suboptimal response to their present therapy. BTX-B is antigenically distinct from BTX-A and possesses a different mechanism of action. Three randomized, double-blind, placebo-controlled clinical trials evaluated the safety and efficacy of BTX-B (Elan's BTX-B evaluated as NeuroBloc) as a treatment for patients with CD. Patients received a single dose of BTX-B ranging from 2,500 to 10,000 U. The primary efficacy evaluation for each of these studies used the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score. Additional efficacy measures included the TWSTRS severity, disability, and pain subscale scores, as well as the Patient Analog Pain Assessment and Patient's and Physician's Global Assessments of Change. In all three studies, groups receiving BTX-B displayed statistically significant improvements in TWSTRS total score and other efficacy end points compared with those who received placebo treatment. The clinical benefits after BTX-B treatment lasted 12 to 16 weeks and were observed in both BTX-A-responsive and BTX-A-resistant patients. In general, treatment with BTX-B was well tolerated and most of the reported adverse events were of short duration, mild to moderate in severity, and anticipated. The results from the three controlled clinical trials demonstrate the safety and efficacy of BTX-B in the treatment of patients with CD, including those who are resistant to BTX-A treatment.
颈部肌张力障碍（CD）的特征是颈部和/或肩部肌肉出现异常的、不自主的收缩。将A型肉毒杆菌毒素（BTX-A）直接注射到受影响的肌肉中已成功用于治疗这种疾病。然而，少数患者会对BTX-A治疗产生临床耐药性。此外，在接受治疗的患者中，有一部分对当前治疗的反应并不理想，比例尚不清楚。BTX-B与BTX-A在抗原性上不同，作用机制也不同。三项随机、双盲、安慰剂对照的临床试验评估了BTX-B（以NeuroBloc评估的伊兰公司的BTX-B）治疗CD患者的安全性和有效性。患者接受了2500至10000单位的单剂量BTX-B。这些研究中的每一项的主要疗效评估都使用了多伦多西部痉挛性斜颈评定量表（TWSTRS）总分。其他疗效指标包括TWSTRS严重程度、残疾程度和疼痛子量表得分，以及患者模拟疼痛评估和患者及医生对变化的整体评估。在所有三项研究中，与接受安慰剂治疗的患者相比，接受BTX-B治疗的组在TWSTRS总分和其他疗效终点方面均有统计学上的显著改善。BTX-B治疗后的临床益处持续12至16周，在对BTX-A有反应和对BTX-A耐药的患者中均有观察到。总体而言，BTX-B治疗耐受性良好，报告的大多数不良事件持续时间短，严重程度为轻至中度，且在预期范围内。三项对照临床试验的结果证明了BTX-B治疗CD患者的安全性和有效性，包括那些对BTX-A治疗耐药的患者。
