Efficacy and safety of botulinum neurotoxin type A free of complexing proteins (NT 201) in cervical dystonia and blepharospasm

Cost-Effectiveness of Incobotulinumtoxin-A with Flexible Treatment Intervals Compared to Onabotulinumtoxin-A in the Management of Blepharospasm and Cervical Dystonia

BACKGROUND

Incobotulinumtoxin-A (Xeomin(®), Merz Pharmaceuticals, Sydney, New South Wales) is a formulation of botulinum neurotoxin type A that is free of complexing proteins.

OBJECTIVE

To assess the cost-effectiveness of incobotulinumtoxin-A administered with flexible treatment intervals compared to onabotulinumtoxin-A (Botox(®), Sydney, New South Wales) in blepharospasm and cervical dystonia from the perspective of Australian health care providers.

METHODS

A Markov state transition model was developed to perform a cost-utility analysis to compare the cost and health benefits of incobotulinumtoxin-A to that of onabotulinumtoxin-A. The cost-utility analysis compared incobotulinumtoxin-A treatment, given at minimum intervals of 6 weeks and maximum intervals of 20 weeks, with onabotulinumtoxin-A treatment, given at minimum intervals of 12 weeks and maximum intervals of 20 weeks. The Markov model consisted of three health states and followed patients in weekly cycles for 5 years. Only direct health care costs associated with the acquisition and administration of type A botulinum neurotoxins were included. Utility values were derived from a prospective, open-labeled cohort study. The primary outcome measure was the incremental cost per quality-adjusted life-year. Univariate and probabilistic sensitivity analyses were conducted.

RESULTS

Incobotulinumtoxin-A was cost-effective compared to onabotulinumtoxin-A in both blepharospasm and cervical dystonia, with an incremental cost/quality-adjusted life-year gained of A$ 25,588 and A$ 23,794, respectively.

CONCLUSIONS

Incobotulinumtoxin-A administered at flexible treatment intervals determined by the needs of the patient was found to be a cost-effective treatment option when compared to the administration of onabotulinumtoxin-A in the Australian health care system. The option to administer incobotulinumtoxin-A according to the needs of the patient resulted in patients experiencing symptoms for a fewer number of weeks compared to onabotulinumtoxin-A given at minimum 12-week intervals.

A comparative, prospective, split-face, blind study of the efficacy of two botulinum toxin type A drugs (Disport® and Xeomin®) used to correct lateral periorbital wrinkles

A prospective- blind- split-face- comparative study with evaluation of clinical efficacy- tolerability- and safety parameters of two botulinum toxin A (BTA) products (the one containing complexing proteins — Disport®- Ipsen- France/ abobotulinumtoxinA and the one free from complexing proteins — Xeomin®- Merz Pharma- Germany/incobotulinumtoxinA) used for correction of lateral periorbital wrinkles (crow's feet) was performed (at that- electromyographic evaluation of changes in functions of the orbicular muscle of eye was performed for the first time). Materials and Methods. Single injections of both BTA products with equal dose ratio of 3:1 (27 IU Disport® and 9 IU Xeomin®) were performed simultaneously to the right and left side half of the face (orbicular muscles of eye)- respectively- to each of 20 volunteers (women at the age of 40.9) with marked and moderate lateral periorbital wrinkles (2—3 degree according to 4-point Facial Wrinkle Scale/FWS). Clinical and electromyographic assessment was performed 2 weeks- 4 and 6 months after injections. Results. The effect of single dosing of Disport® and Xeomin® did not significantly differ at all assessment time points: both for primary efficacy criterion and for all secondary efficacy criteria; as well as for clinical evaluation by the investigator-subjects’ self-evaluation- and dynamics of M-response parameters for the orbicular muscle of eye. Good tolerability and safety were registered. Conclusion. Study results provided convincing evidence that Disport® and Xeomin® used in accordance with the proposed protocol had a comparable effect and duration of the effect on lateral periotbital wrinkles and the orbicular muscle of eye.

Comparative evaluation of the potency and antigenicity of two distinct BoNT/A-derived formulations

IncobotulinumtoxinA (Xeomin®) and onabotulinumtoxinA (BOTOX®) are unique botulinum neurotoxin type A (BoNT/A)-derived drugs. IncobotulinumtoxinA utilizes the naked 150 kDa holotoxin portion of BoNT/A, whereas onabotulinumtoxinA uses the complete native 900 kDa complex as drug substance. On the basis of purportedly similar pharmacological characteristics, these formulations were evaluated for potency by LD₅₀ and mouse Digit Abduction Score (DAS) bioassays. DAS was also used to assess antigenicity. Full-range DAS dose-response profiles were achieved with four lots of each product, with similar observations between lots for a given product. Between products, however, the mean DAS potency of incobotulinumtoxinA (ED₅₀ range 7.0-10.2 U/kg) was significantly lower than that of onabotulinumtoxinA (ED₅₀ range 4.4-6.4 U/kg), consistent with lower measured potencies in the LD₅₀ assay for incobotulinumtoxinA (potency range 62-82 U). In assessments of DAS duration of effect at similar unit doses, the observed lower potency of incobotulinumtoxinA translated into decreased peak efficacy and dose effect over time (i.e. shorter duration). In contrast, at equi-efficacious doses yielding near-maximal DAS responses, both toxin formulations were uniformly inhibited in a statistically significant manner when preincubated with rabbit-derived, onabotulinumtoxinA-neutralizing antibodies, supporting the position that inhibition of 150 kDa holotoxin serves as the common basis for neutralization and, therefore, incobotulinumtoxinA would not be expected to be effective in onabotulinumtoxinA-immunoresistant subjects (and vice versa). Further, with lower lot-to-lot relative potency, incobotulinumtoxinA is not dose-equivalent or interchangeable with onabotulinumtoxinA, suggesting that various aspects of drug product formulation may influence observed pharmacology.

Cervical dystonia

Cervical dystonia is a common disorder with significant associated morbidity. Although limited benefit can be derived from oral pharmacologic agents, the advent of botulinum neurotoxin (BoNT) injection has provided a valuable tool in the treatment of this disorder. In order to provide effective treatment, the physician must have an intimate knowledge of the anatomy and function of the neck musculature. Novel BoNT formulations, even of the same serotype, are not equivalent and thus require careful dose titration. Formulation improvements may result in reduced immunoresistance. In patients labeled as treatment resistant to BoNT, careful electromyographic reassessment of select muscles for injection will frequently result in improved clinical benefit.