Pharmacotherapeutic group: other muscle relaxants, peripherally acting agents,
ATC code: M03AX01
Botulinum neurotoxin type A blocks cholinergic transmission at the neuromuscular junction by inhibiting the release of acetylcholine. The nerve terminals of the neuromuscular junction no longer respond to nerve impulses, and secretion of the neurotransmitter at the motor endplates is prevented (chemical denervation). Recovery of impulse transmission is re-established by the formation of new nerve terminals and reconnection with the motor endplates.
Mechanism of action
The mechanism of action by which Botulinum neurotoxin type A exerts its effects on cholinergic nerve terminals can be described by a four-step sequential process which includes the following steps:
• Binding: The heavy chain of Botulinum neurotoxin type A binds with exceptionally high selectivity and affinity to receptors only found on cholinergic terminals.
• Internalisation: Constriction of the nerve terminal's membrane and absorption of the toxin into the nerve terminal (endocytosis).
• Translocation: The amino-terminal segment of the neurotoxin's heavy chain forms a pore in the vesicle membrane, the disulphide bond is cleaved and the neurotoxin's light chain passes through the pore into the cytosol.
• Effect: After the light chain is released, it very specifically cleaves the target protein (SNAP 25) that is essential for the release of acetylcholine.
Complete recovery of endplate function/impulse transmission after intramuscular injection normally occurs within 3‑4 months as nerve terminals sprout and reconnect with the motor endplate.
Results of the clinical studies
Therapeutic equivalence of XEOMIN as compared to the comparator product Botox containing the Botulinum toxin type A complex (onabotulinumtoxinA, 900 kD) was shown in two comparative single-dosing Phase III studies, one in patients with blepharospasm (study MRZ 60201-0003, n=300) and one in patients with cervical dystonia (study MRZ 60201-0013, n=463). Study results also suggest that XEOMIN and this comparator product have a similar efficacy and safety profile in patients with blepharospasm or cervical dystonia when used with a dosing conversion ratio of 1:1 (see section 4.2).
Blepharospasm
XEOMIN has been investigated in a Phase III, randomised, 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 the comparator product (onabotulinumtoxinA).
Patients were randomised (2:1) to receive a single administration of XEOMIN (n=75) or placebo (n=34) at a dose that was similar (+/- 10 %) to the 2 most recent Botox injection sessions prior to study entry. The highest dose permitted in this study was 50 units per eye; the mean XEOMIN dose was 32 units per eye.
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 (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 and statistically significant (p<0.001).
Patients could continue with the Extension Period if a new injection was required. The patients received up to five injections of XEOMIN with a minimum interval between two injections of at least six weeks (48‑69 weeks total study duration and a maximum dose of 50 units per eye. Over the entire study, the median injection interval in subjects treated with Xeomin ranged between 10.14 (1st interval) and 12.00 weeks (2nd to 5th interval).
Another double-blind, placebo-controlled Phase III clinical trial with an open-label extension period investigated efficacy of XEOMIN in a total of 61 patients, with a clinical diagnosis of benign essential blepharospasm and baseline Jankovic Rating Scale (JRS) severity subscore ≥ 2, who were Botulinum toxin treatment-naïve, i.e., who had not received any Botulinum toxin treatment of blepharospasm for at least 12 months prior to administration of XEOMIN. In the main period (6‑20 weeks), the patients were randomised to receive a single administration of XEOMIN at the doses of 12.5 units per eye (n=22), 25 units per eye (n=19) or placebo (n=20), respectively. The patients requiring a new injection could continue with the extension period and received one further injection of XEOMIN.
In the main period, the median duration of the treatment interval was 6 weeks in the placebo group, 11 weeks in the group treated with 12.5 units per eye, and 20 weeks in the group treated with 25 units per eye. The ANCOVA LS mean difference vs. placebo (95% CI) in the change of the JRS severity subscore from baseline to week 6 was -1.2 (-1.9, -0.6) in the group administered 25 units XEOMIN per eye and found statistically significant, whereas the respective difference vs. placebo in the group given XEOMIN 12.5 units was -0.5 (-1.1, 0.2) which was not statistically significant.
During the extension period the patients received an injection of XEOMIN (n=39) at a mean dose close to 25 units (range: 15‑30 units) per eye, and the median duration of the treatment interval was 19.9 weeks.
Spasmodic torticollis
XEOMIN has been investigated in a Phase III, randomised, 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. Patients were randomised (1:1:1) to receive a single administration of XEOMIN 240 units (n=81), XEOMIN 120 units (n=78), or placebo (n=74). The number and sites of the injections were to be determined by the Investigator.
The primary efficacy variable was the LS mean change from Baseline to Week 4 following injection in the TWSTRS-Total score, in the Intent-to-Treat (ITT) Population with missing values replaced by the patient's baseline value (full statistical model). The change in TWSTRS-Total score from Baseline to Week 4 was significantly greater in the Xeomin groups, compared with the change in the placebo group (p<0.001 across all statistical models). These differences were also clinically meaningful: e.g. ‑9.0 points for 240 units vs. placebo, and ‑7.5 points for 120 units vs. placebo in the full statistical model.
Patients could continue with the Extension Period if a new injection was required. The patients received up to five injections of 120 units or 240 units of XEOMIN with a minimum interval between two injections of at least six weeks (48‑69 weeks total study duration). Over the entire study, the median injection interval in subjects treated with Xeomin ranged between 10.00 (1st interval) and 13.14 weeks (3rd and 6th interval). Based on the patient's request for retreatment, the median duration of response following Xeomin treatment in this study (both double-blind and the open-label extension period) was 12 weeks (Interquartile ranges: 9 to 15 weeks). In the majority of injection cycles (96.3%) the time to retreatment was between 6 and 22 weeks and in individual cases up to 28 weeks.
Focal spasticity of the upper limb (adults)
In the pivotal study (double-blind, placebo-controlled, multicentre) conducted in patients with post-stroke spasticity of the upper limb, 148 patients were randomised to receive XEOMIN (n=73) or Placebo (n=75). The cumulative dose after up to 6 repeated treatments in a clinical trial was in average 1333 units (maximum 2395 units) over a period of up to 89 weeks.
As determined for the primary efficacy parameter (response rates for the wrist flexors Ashworth Scale score at Week 4, response defined as improvement of at least 1‑point in the 5‑point Ashworth Scale score), patients treated with XEOMIN (response rate: 68.5 %) had a 3.97 fold higher chance of being responders relative to patients treated with placebo (response rate: 37.3 %; 95 % CI: 1.90 to 8.30; p<0.001, ITT population).
This fixed dose study was not designed to differentiate between female and male patients, nevertheless in a post-hoc analysis the response rates were higher in female (89.3 %) compared to male (55.6 %) patients, the difference being statistically significant for women only. However, in male patients response rates in Ashworth Scale after 4 weeks in XEOMIN treated patients were consistently higher in all muscle groups treated compared to placebo. Based on the patient's request for retreatment, the median duration of effect in this pivotal study followed by the open-label extension period was 14 weeks (Interquartile ranges: 13 to 17 weeks) and in the majority of injection cycles (95.9%) the time to retreatment was between 12 and 28 weeks.
Responder rates were similar in men compared to women in the open label extension period of the pivotal study (flexible dosing was possible in this trial period) in which 145 patients were enrolled and up to 5 injection cycles were performed, as well as in the observer-blind study (EudraCT Number 2006-003036-30) in which efficacy and safety of XEOMIN in two different dilutions in 192 patients were assessed in patients with upper limb spasticity of diverse aetiology.
Another double-blind, placebo-controlled Phase III clinical trial enrolled a total of 317 treatment-naïve patients with spasticity of the upper limb who were at least three months post-stroke. During the Main Period (MP) a fixed total dose of XEOMIN (400 units) was administered intramuscularly to the defined primary target clinical pattern chosen from among the flexed elbow, flexed wrist, or clenched fist patterns and to other affected muscle groups (n=210). The confirmatory analysis of the primary and co-primary efficacy variables at week 4 post-injection demonstrated statistically significant improvements in the responder rate of the Ashworth score, or changes from baseline in the Ashworth score and the Investigator's Global Impression of Change.
296 treated patients completed the MP and participated in the first Open-label Extension (OLEX) cycle. During the Extension Period patients received up to three injections. Each OLEX cycle consisted of a single treatment session (400 units of XEOMIN total dose, distributed flexibly among all affected muscles) followed by a 12 week-observation period. The overall study duration was 48 weeks.
Focal spasticity of the lower limb affecting the ankle joint (adults)
The pivotal double-blind, placebo-controlled Phase III clinical trial enrolled a total of 219 Asian (Japanese) patients with unilateral spasticity of the lower limb presenting with equinus foot deformity (Modified Ashworth Scale [MAS] of plantar flexors of at least 3) who were at least six months post-stroke. The study comprised an open-label lead-in tolerability period, a double-blind Main Period (MP) and an Open-Label Extension (OLEX) period.
During the MP, 208 patients were randomised 1:1 to receive either a fixed total dose of XEOMIN (400 units) or placebo. This was administered intramuscularly to the study mandatory muscles gastrocnemius (medial and lateral head), soleus, tibialis posterior and to the toe muscles (flexor digitorum longus and flexor hallucis longus), if needed.
The primary endpoint was the area under the curve (AUC) of the change from baseline (Day 1) in MAS plantar flexors score to the end of the MP (Week 12). Secondary endpoints were the change from baseline in MAS plantar flexors score to Week 4, Week 6, and Week 8, and the response rates in MAS plantar flexors score at Week 4, 6, and 8 where responders were defined as subjects with an improvement (=reduction) of at least 1 point from baseline.
A statistically significant difference was demonstrated between Xeomin and placebo for the primary endpoint measure; for the secondary endpoint measure change from baseline in MAS plantar flexors score to Week 4, Week 6, and Week 8; and for the secondary endpoint measure response rates in MAS plantar flexors score at Weeks 4, 6, and 8 as shown in the tables below.
Primary Efficacy Endpoint Results (AUC of the change from baseline in MAS plantar flexors score to the end of Week 12):
| | Xeomin 400 units (N=104) | Placebo (N=104) |
| Mean change (SD) | -7.74 (7.01) | -4.76 (5.84) |
| LS mean change (SE) | -8.40 (0.661) | -5.81 (0.713) |
| LS mean difference (SE) | -2.59 (0.892) 95% CI = [-4.35; -0.83] p =0.0041 |
| CI: Confidence Interval; N: Number of exposed subjects in treatment group; SE: Standard Error; SD: Standard deviation |
Secondary Efficacy Endpoint Results (change from baseline in MAS plantar flexors score to Weeks 4, 6, and 8):
| Timepoint | Xeomin 400 units (N=104) | Placebo (N=104) | p-value |
| LS mean change (SE) | LS mean change (SE) |
| Week 4 | –0.81 (0.070) | –0.57 (0.076) | 0.0125 |
| Week 6 | –0.91 (0.076) | –0.62 (0.082) | 0.0042 |
| Week 8 | –0.81 (0.071) | –0.52 (0.076) | 0.0033 |
| LS: Least Square; N: Number of exposed subjects in treatment group; SE: Standard Error |
Secondary Efficacy Endpoint Results (response rates in MAS plantar flexors score at Weeks 4, 6, and 8):
| Timepoint | Xeomin 400 units (N = 104) | Placebo (N = 104) | Odds ratio | p-value |
| n (%) | n (%) | [95% CI] |
| Week 4 | 58 (55.8) | 43 (41.3) | 1.72 [0.98; 3.02] | 0.0577 |
| Week 6 | 62 (59.6) | 41 (39.4) | 2.16 [1.23; 3.80] | 0.0074 |
| Week 8 | 55 (52.9) | 35 (33.7) | 2.05 [1.16; 3.64] | 0.0140 |
| CI: Confidence Interval; N: Number of exposed subjects in treatment group; n: Number of non-missing observations |
A total of 202 patients were enrolled in the OLEX period from the LITP and MP during which patients received up to three injection cycles. Each OLEX cycle consisted of a single treatment session (fixed total dose of 400 units of XEOMIN) followed by an observation period of 10 to 14 weeks for the 1st and 2nd OLEX cycle and of 12 weeks for the 3rd OLEX cycle. The overall study duration was up to 52 weeks. Results from the OLEX confirmed the findings of the MP showing continued treatment benefit.
Focal spasticity of the upper and lower limbs (adults)
Safety data to support the maximum total body dose of 600 units for combined treatment of focal spasticity of the upper and lower limbs in adults is derived from a supportive uncontrolled, open-label Phase III study which included 155 patients with a clinical need for treatment of combined upper and lower limb spasticity.
Spasticity of the lower and upper limb due to cerebral palsy (children/adolescents)
Lower limb evaluation
In a double-blind, parallel-group, dose-response Phase III clinical study 311 children and adolescents (aged 2‑17 years) with uni- or bilateral lower limb spasticity due to cerebral palsy were enrolled. For treatment of lower limb spasticity XEOMIN was administered in three treatment groups (4 units/kg body weight with a maximum of 100 units, 12 units/kg body weight with a maximum of 300 units or 16 units/kg body weight with a maximum of 400 units, respectively) for treatment of two selected lower limb clinical patterns (pes equinus, flexed knee, adducted thigh).
In this study the low dose group was intended to act as control group. No statistically significant differences were demonstrated in the comparison of the high dose vs low dose neither regarding the primary nor the co-primary efficacy endpoint. LS-Mean change (SE, 95% CI) from baseline in Ashworth Scale of plantar flexors 4 weeks after injection was -0.70 (0.061, 95% CI: -0.82; -0.58) for the high dose and -0.66 (0.084, 95% CI: -0.82; -0.50) for the low dose with a p-value of 0.650. Improvement in muscle tone was not reflected in an effect on function or Investigator's Global Impression of Change. Adequate posology of XEOMIN for the treatment of lower limb spasticity in children and adolescents cannot be determined. No unexpected adverse events were observed in the double-blind treatment and open-label long-term treatment with XEOMIN over four injection cycles.
Upper limb evaluation
In a second double-blind, parallel-group, dose-response Phase III study a total of 350 children and adolescents (aged 2‑17 years) with upper limb spasticity alone or with combined upper and lower limb spasticity due to cerebral palsy were treated with XEOMIN. For treatment of upper limb (flexed elbow, flexed wrist, clenched fist, pronated forearm, thumb-in-palm) or combined upper and lower limb spasticity (pes equinus, flexed knee, adducted thigh) XEOMIN was administered in three treatment groups in the Main Period with one injection cycle: 2 to 5 units/kg body weight with a maximum of 50 to 125 units, 6 to 15 units/kg body weight with a maximum of 150 to 375 units and 8 to 20 units/kg body weight with a maximum of 200 to 500 units. Patients continued with the highest dose in the Open-label Extension Period of the study with three injection cycles.
A statistical significant difference between the low and high dose was seen in change from baseline in Ashworth Scale for elbow flexor or wrist flexor at week 4 post injection (-0.22 [95% CI -0.4;-0.04] p=0.017). Improvements in muscle tone was not reflected in an effect on function and Investigator's Global Impression of Change. Adequate posology of XEOMIN for the treatment of upper limb spasticity in paediatric patients can therefore not be determined from this study.
No unexpected safety concerns were reported in the upper limb and lower limb spasticity treatment with XEOMIN up to four injection cycles (14± 2 weeks each).
Chronic sialorrhea (adults)
The pivotal double-blind, placebo-controlled Phase III clinical trial enrolled a total of 184 patients suffering at least three months from sialorrhea resulting from Parkinson's disease, atypical parkinsonism, stroke or traumatic brain injury. During the Main Period (MP) a fixed total dose of XEOMIN (100 or 75 units) or placebo was administered intraglandularly at a defined dose ratio of 3:2 into parotid and submandibular salivary glands, respectively.
| | | uSFR (g/min) | GICS (score points) |
| Treatment | Timepoint | n obs | LS mean (SE) | n obs | LS mean (SE) |
| Placebo | Week 4 | 36 | -0.04 (0.033) | 36 | 0.67 (0.186) |
| 100 units | Week 4 | 73 | -0.13 (0.026) | 74 | 1.25 (0.144) |
| 100 units | Week 8 | 73 | -0.13 (0.026) | 74 | 1.30 (0.148) |
| 100 units | Week 12 | 73 | -0.12 (0.026) | 74 | 1.21 (0.152) |
| 100 units | Week 16 | 73 | -0.11 (0.027) | 74 | 0.93 (0.152) |
| uSFR: Unstimulated Salivary Flow Rate; GICS: Global Impression of Change Scale n obs: Number observed; LS: Mean difference to baseline; SE: Standard Error |
At week 4, at least 1 point improvement on GICS (co-primary endpoint) was observed in 73% of patients treated with 100 units of XEOMIN compared to 44% of patients in the placebo group. The confirmatory analysis of both co-primary efficacy variables (uSFR and GICS at week 4 post-injection) demonstrated statistically significant improvements of the 100 units treatment group compared to placebo. Improvements in efficacy parameters at weeks 8 and 12 post-injection could be shown and were maintained up to the last observation point of the MP at week 16. Co-primary efficacy variables at week 4 demonstrated superior results for ultrasound guided application in comparison with anatomic landmark method (uSFR p-value 0.019 vs 0.099 and GICS 0.003 vs 0.171).
173 treated patients completed the MP and entered the Extension Period (EP). The EP consisted of three dose-blinded cycles each with a single treatment session (100 or 75 units of XEOMIN total dose, with the same dose ratio as in the MP) followed by a 16 week-observation period. 151 patients completed the EP. Results from the EP confirmed the findings of the MP showing continued treatment benefits of 100 units XEOMIN.
Chronic sialorrhea (children/adolescents)
In one double-blind, placebo-controlled Phase III clinical trial, a total of 255 children and adolescents (aged 2‑17 years) with a body weight (BW) of at least 12 kg suffering from chronic sialorrhea associated with neurological disorders and/or intellectual disability were treated. During the Main Period (MP), 220 patients aged 617 years received XEOMIN treatment according to BW class and up to 75 U, or placebo. Treatment was administered ultrasound guided intraglandularly with a defined dose ratio of 3:2 into the parotid and submandibular salivary glands, respectively.
| | | uSFR (g/min) | GICS (score points) |
| Treatment | Timepoint | n obs | LS mean (SE) | n obs | LS mean (SE) |
| Placebo | Week 4 | 72 | -0.07 (0.015) | 72 | 0.63 (0.104) |
| XEOMIN according to BW class | Week 4 | 148 | -0.14 (0.012) | 148 | 0.91 (0.075) |
| Week 8 | 146 | -0.16 (0.012) | 146 | 0.94 (0.068) |
| Week 12 | 147 | -0.16 (0.013) | 147 | 0.87 (0.073) |
| Week 16 | 145 | -0.15 (0.013) | 146 | 0.77 (0.070) |
| uSFR: Unstimulated Salivary Flow Rate; GICS: Global Impression of Change Scale; BW: Body Weight; n obs: Number observed; LS: Mean difference to baseline; SE: Standard Error |
The confirmatory analysis of the co-primary efficacy variables (uSFR and GICS at week 4 post-injection) demonstrated statistically significant and clinically relevant improvements of the XEOMIN group compared to placebo. For both efficacy parameters, statistically significant differences between treatment groups were observed until the end of the MP at week 16.
All 35 children aged 2‑5 years were treated with XEOMIN according to their BW class, no placebo arm was used as control showing an improvement in the investigated efficacy variables similar to those observed in the 6‑17 years XEOMIN treatment group.
247 patients participated in the subsequent first cycle of the Open-label Extension Period (OLEX). The OLEX consisted of three additional cycles, each with a single treatment session followed by a 16‑week observation period. All patients received XEOMIN according to the same pre-determined dosing scheme and the same dose ratio used in the MP. A total of 222 patients completed the OLEX. Results from the OLEX confirmed the findings of the MP showing continued treatment benefits. No new or unexpected safety concerns were identified.
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with XEOMIN:
• in all subsets of the paediatric population in the treatment of dystonia
• in infants and toddlers from 0‑24 months in the treatment of muscle spasticity and chronic sialorrhea.
See section 4.2 for information on paediatric use.