Practical Application of Novel Test Methods to Evaluate the Potency of Botulinum Toxin: A Comparison Analysis among Widely Used Products in Korea

A Phase-III Noninferiority, Randomized Controlled Trial of Letibotulinum Toxin A for the Improvement of Moderate-to-Severe Glabellar Wrinkles in China

Background

Letibotulinum toxin A has an established efficacy and safety profile for aesthetic treatment of glabellar wrinkles. This study was conducted to demonstrate the noninferiority of letibotulinum toxin A versus onabotulinum toxin A in improving the appearance of moderate-to-severe glabellar wrinkles in Chinese patients.

Methods

This phase-III multicenter, randomized, parallel positive control, double-blinded study compared the efficacy and safety of letibotulinum toxin A and onabotulinum toxin A. Eligible participants were randomized 3:1 to receive 20 U of letibotulinum toxin A or onabotulinum toxin A and were observed for 16 weeks postinjection. The primary endpoint was noninferiority in the proportion of study participants receiving a score of 0 or 1 for glabellar wrinkles on a four-point photographic evaluation scale, as assessed by an institution evaluator at maximum frown at week 4. Secondary endpoints included assessments at rest, photographic assessment of efficacy, and subjective self-assessment of the study participants.

Results

The proportion of participants (N = 500) receiving a score of 0 or 1 at maximum frown by the institution evaluator at week 4 was 88.49% for letibotulinum toxin A and 87.39% for onabotulinum toxin A (difference, 1.10%; 95% confidence interval, -5.02 to 8.82; P = 0.7469). No significant differences were observed between the treatments for secondary efficacy or safety endpoints. Participants' self-assessment and satisfaction tended to be higher for letibotulinum toxin A than onabotulinum toxin A.

Conclusion

Letibotulinum toxin A is noninferior to onabotulinum toxin A in improving the appearance of moderate-to-severe glabellar wrinkles in Chinese patients.

An Update on the Cosmetic Use of Botulinum Toxin: The Pattern of Practice among Korean Dermatologists

The efficacy and safety of botulinum toxin injection have made it a popular aesthetic procedure worldwide. A cross-sectional survey was performed in order to determine the pattern of type A botulinum toxin injections in cosmetic practice, for which an 18-item questionnaire was distributed to dermatologists. A total of 469 Korean board-certified dermatologists participated in the survey, with the following results: the main candidates for type A botulinum toxin injection were individuals in their 40–50 years (46.1%), followed by those in their 20–30 years (33.4%), and people over 60 years of age (20.5%). Overall, the upper face (the glabella, forehead, and crow’s line, in decreasing order) was the most favored area of injection (51%). In contrast, body contouring (i.e., shoulder, calf) and treatment for benign masseter hypertrophy were significantly more popular in the 20–30 years age group than their older counterparts. For wrinkle effacement, the most preferred dilution was 100 units/2.5 mL with isotonic sodium chloride injection (51.2%), and the most often used interval was six months (43.6%). About half (46.3%) of the dermatologists reported the experience of clinical cases which were suspicious of botulinum toxin resistance. Despite this, regarding the choice of the product, type A botulinum toxin products with greater cost-effectiveness were favored over products with a lower risk of antibody formation. Other than its cosmetic usage, botulinum toxin is applied for a variety of skin conditions. Further studies are suggested in order to identify the practice pattern of type A botulinum toxin for therapeutic uses in dermatology, such as hyperhidrosis and rosacea.