CLINICAL STUDIES
Cervical Dystonia
XEOMIN has been investigated in a Phase 3, randomized, double-blind, placebo-controlled, multi-center trial in a total of 233 patients with cervical dystonia. Patients had a clinical diagnosis of predominantly rotational cervical dystonia, with baseline Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score ≥20, TWSTRS severity score ≥10, TWSTRS disability score ≥3, and TWSTRS pain score ≥1. For patients who had previously received a botulinum toxin treatment for cervical dystonia, the trial required that ≥10 weeks had passed since the most recent botulinum toxin administration. Patients with swallowing disorders or any significant neuromuscular disease that might interfere with the study were excluded from enrollment. Patients were randomized (1:1:1) to receive a single administration of XEOMIN 240 Units (n=81), XEOMIN 120 Units (n=78), or placebo (n=74). Each patient received a single administration of 4.8 mL of reconstituted study agent (XEOMIN 240 Units, XEOMIN 120 Units, or placebo). The investigator at each site decided which muscles would receive injections of the study agent, the number of injection sites, and the volume at each site. The muscles most frequently injected were the splenius capitis/semispinalis, trapezius, sternocleidomastoid, scalene, and levator scapulae muscles. Table 2 indicates the average XEOMIN dose, and percentage of total dose, injected into specific muscles in the pivotal clinical trial.
Table 4: XEOMIN 120 Units Initial Dose (Units and % of the Total Dose) by Unilateral Muscle Injected During Double Blind Pivotal Phase 3 Study
|
|
XEOMIN Dose Injected |
|
Number of Patients Injected Per Muscle |
Median XEOMIN Units |
75th percentile XEOMIN Units |
|
Sternocleidomastoid
|
63 |
25 |
35 |
|
Splenius capitis/ Semispinalis capitis
|
78 |
48 |
63 |
|
Trapezius
|
55 |
25 |
38 |
|
Levator scapulae
|
49 |
25 |
25 |
|
Scalenus (medius and anterior)
|
27 |
20 |
25 |
Most patients received a total of 2-10 injections into the selected muscles. Patients were assessed by telephone at one week post-injection, during clinic visits at Weeks 4 and 8, and then by telephone assessments or clinic visits every two weeks up to Week 20.
The mean age of the study patients was 53 years, and 66% of the patients were women. At study baseline, 61% of patients had previously received a botulinum toxin as treatment for cervical dystonia. The study was completed by 94% of study patients. Three patients discontinued the study prematurely due to adverse events: two patients in the 240 Unit group experienced musculoskeletal pain and muscle weakness, and one patient in the 120 Unit group experienced nausea and dizziness.
The primary efficacy endpoint was the change in the TWSTRS total score from baseline to Week 4 post-injection, in the intent-to-treat (ITT) population, with missing values replaced by the patient's baseline value. In the ITT population, the difference between the XEOMIN 240 Unit group and the placebo group in the change of the TWSTRS total score from baseline to Week 4 was -9.0 points, 95% confidence interval (CI) -12.0; -5.9 points; the difference between the XEOMIN 120 Unit group and the placebo group in the change of the TWSTRS total score from baseline to Week 4 was -7.5 points, 95% CI -10.4; -4.6 points.
Figure 1 illustrates the cumulative percentage of patients from each of the three treatment groups who had attained the specified change in TWSTRS Score from baseline versus 4 weeks post-injection. Three change scores have been identified for illustrative purposes, and the percent of patients in each group achieving that result is shown.
Figure 1: Cumulative Percentage of Patients with Specified Changes from Baseline TWSTRS Total Score at Week 4
The curves demonstrate that both patients assigned to placebo and XEOMIN have a wide range of responses, but that the active treatment groups are more likely to show greater improvements. A curve for an effective treatment would be shifted to the left of the curve for placebo, while an ineffective or deleterious treatment would be superimposed upon or shifted to the right of the curve for placebo.
Comparison of each XEOMIN group to the placebo group was statistically significant at p<0.001. Initial XEOMIN doses of 120 Units and 240 Units demonstrated no significant difference in effectiveness between the doses. The efficacy of XEOMIN was similar in patients who were botulinum toxin naive and those who had received botulinum toxin prior to this study.
Examination of age and gender subgroups did not identify differences in response to XEOMIN among these subgroups. There were too few African-American patients to adequately assess efficacy in that population.
Blepharospasm
XEOMIN has been investigated in a Phase 3, randomized, double-blind, placebo-controlled, multi-center trial in a total of 109 patients with blepharospasm. Patients had a clinical diagnosis of benign essential blepharospasm, with baseline Jankovic Rating Scale (JRS) Severity subscore ≥2, and a stable satisfactory therapeutic response to previous administrations of onabotulinumtoxinA (Botox). At least 10 weeks had to have elapsed since the most recent onabotulinumtoxinA administration. Patients with any significant neuromuscular disease that might interfere with the study were excluded from enrollment. Patients were randomized (2:1) to receive a single administration of XEOMIN (n=75) or placebo (n=34). Each patient in the XEOMIN group received a XEOMIN treatment (dose, volume, dilution, and injection sites per muscle) that was similar to the most recent onabotulinumtoxinA injection sessions prior to study entry. The highest dose permitted in this study was 50 Units per eye; the mean XEOMIN dose was 33 Units per eye.
In Table 5 the most frequently injected sites, the median dose per injection site, and the median number (and range) of injection sites per eye are presented.
Table 5: Median Dose and Median Number of Injection Sites per Eye (Blepharospasm)
| Injection Area |
Median Units XEOMIN |
Median Number of Injection Sites
(Min-Max) |
|
Temporal Area
|
13 |
2 (1 — 6) |
|
Eyebrow Area
|
5 |
1 (1 — 4) |
|
Upper Lid Area
|
10 |
2 (1 — 4) |
|
Lower Lid Area
|
8 |
2 (1 — 3) |
|
Orbital Rim
|
5 |
1 (1 — 3) |
Patients were assessed during clinic visits at Weeks 3 and 6, and then by telephone or at clinic visits every two weeks up to Week 20.
The mean age of the study patients was 62 years, and 65% of the patients were women. The study was completed by 94% of study patients. Approximately one third of patients had other dystonic phenomena; in all but 1% this was limited to facial, cervical, perioral and mandibular muscles. No patients discontinued the study prematurely due to adverse events.
The primary efficacy endpoint was the change in the JRS Severity subscore from baseline to Week 6 post-injection, in the intent-to-treat (ITT) population, with missing values replaced by the patient's most recent value (i.e., last observation carried forward). In the ITT population, the difference between the XEOMIN group and the placebo group in the change of the JRS Severity subscore from baseline to Week 6 was -1.0 (95% CI -1.4; -0.5) points. Comparison of the XEOMIN group to the placebo group was statistically significant at p<0.001.
Figure 2: Frequency Distribution of Changes from Baseline JRS Severity Subscore at Week 6
Examination of age and gender subgroups did not identify substantial differences in response to XEOMIN among these subgroups. There were too few African-American patients to assess efficacy in that population.
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