Table 1
Withdrawal Data from Selected Retrospective Studies of Long-Term BoNT-A Treatment for CD in Clinical Practice
| Study Citation | N | Study Period (years) | Withdrawals/Total, Reasons n (%) | |||||
|---|---|---|---|---|---|---|---|---|
| Total | Primary Non-response | Secondary Non-response | AEs | Remission/Improvement | Other1 | |||
| Kessler et al.,26, 2 | 616 | 7 | 126 (20.5) | 33 (5.4) | 17 (2.8) | 27 (4.4) | 26 (4.2) | 34 (5.5) |
| Hsiung et al.28 | 106 | 10 | 49 (46.2) | 11 (10.4) | 9 (8.5) | 3 (2.8) | 4 (3.8) | 22 (20.8) |
| Haussermann et al.29 | 90 | 12 | 33 (36.7) | 1 (1.1) | 3 (3.3) | 11 (12.2) | 6 (6.7) | 12 (13.3) |
Table 2
Characteristics of Secondary Non-responders and Responders from Retrospective Clinical Practice Study of BoNT-A Treatment for CD (total N = 3571)
| Characteristic, median (range) | Secondary Non-responders (n = 17) | Responders (n = 303) | p-Value2 | |
|---|---|---|---|---|
| Ab+ (n = 9) | Ab− (n = 8) | |||
| Age at onset of symptoms, years | 30 (13–51) | 39 (28–55) | 41 (8–50) | 0.0073 |
| Duration of symptoms, months | ||||
| Before treatment | 38 (19–121) | 47 (12–192) | 58 (2–426) | n.d. |
| Before non-response | 36 (20–53) | 40 (29–72) | – | n.d. |
| MU per session | 875 (400–1750) | 820 (400–2000) | 750 (150–2250) | 0.00013 |
| Cumulative dose (MU) | 9000 (6455–12405) | 9675 (8475–18050) | 7430 (2700–22475) | 0.083 |
| Interval, days | 91 (11–271) | 91 (3–273) | 105 (1–874) | 0.00013 |
| No. of injections | 11 (7–14) | 14 (9–22) | 10.2±3.2 | n.d. |
| Booster4 | 4/96 injections (4.2%) | 7/117 injections (5.9%) | 41/3089 injections (1.3%) | 0.053,5 |
Ab, Neutralizing Antibodies; BoNT-A, Botulinum Toxin Type A; CD, Cervical Dystonia; MU, Mouse Units.
Non-parametric statistical comparisons (two-tailed Mann–Whitney U tests: χ2 only for the booster injections) were performed between the Ab+ group and the responders group.
1 Population included all clinic patients with cervical dystonia over a 7-year period who had received six or more botulinum toxin type A injections (54 patients discontinued; secondary non-response was never seen before the sixth injection).
{ label (or @symbol) needed for fn[@id='TFN08t02'] } Data were previously published by Kessler et al.26
Figure 1
Mean (SD) Toronto Western Spasmodic Torticollis Rating Scale Total Score.
Results at 4 weeks after each of five injection sessions. Error bars represent SD. *p<0.001; p-value is a one-sample t-test of change in TWSTRS total score from the injection visit to the visit 4 weeks later (with no replacement of missing data).
Table 3
Incidence of TEAEs by Interval Group (Pooled Data of Both Treatment Groups) in CD Patients Who Received ≥2 BoNT-A Injections (incobotulinumtoxinA 120 U or 240 U) During the Open Label Extension Phase of a Randomized, Placebo-Controlled Trial
| Interval Group | Number Patients | Incidence of TEAEs | Comparison of Frequency of TEAEs Between Interval Groups |
|---|---|---|---|
| Total N = 191 | Total N = 110 | ||
| n (%) | n (%) | ||
| ≤10 weeks | 43 (22.5) | 31 (72.1) | NS |
| >10 to ≤12 weeks | 47 (24.6) | 22 (46.8) | NS |
| >12 to ≤14 weeks | 37 (19.4) | 21 (56.8) | NS |
| >14 weeks | 64 (33.5) | 36 (56.3) | NS |
[ii] Data were previously published by Evidente et al.59