Topical botulinum toxin has been heavily investigated over the past several years. RT001 is an investigational topical botulinum toxin type A (BoNTA) formulated with a novel peptide delivery system that enables transcutaneous transfer of the botulinum toxin. Results of a randomized, double-blind, placebo-controlled, phase 2 trial of 36 patients on the efficacy and safety of this compound was recently published. In the published report, Brandt and colleagues found topical BoNTA to be efficacious in reducing lateral canthal lines (≥ 2-point improvement on a validated wrinkle severity scale: 50% vs 0% at 8 weeks, P < .001; ≥ 1-point improvement: 94.7% vs 14.7%; P < .001). There were no treatment-related adverse events in this study. Researchers noted that these results were similar to efficacy reports on the injectable forms of BoNTA.
At the 2011 American Society of Plastic Surgeons Annual Meeting, Michael Kane, MD, a plastic surgeon in private practice in New York City, discussed the most recent phase 2 studies on RT001 involving 90 and 180 patients. He summarized the results of 11 clinical trials on RT001, involving over 550 patients, by concluding that the compound has had a 115-day duration of effect with no serious treatment-related adverse events. Speaking more specifically about the recent 90-patient, 3-site, randomly controlled study, he reported a ≥ 2-point improvement in lateral canthal lines in 44% of the treatment group vs 0% in the control group (P < .0001) and a ≥ 1-point improvement in 89% of treated patients vs 28% of controls (P < .0001). For the larger 5-site study, RT001 was compared with each of its 3 components – the BoNTA alone, the transport protein alone, and the gel placebo alone. RT001 results were statistically significant compared with each of the individual components and all 3 components combined (P < .0001). RT001 also showed significant lateral canthal line improvement of at least 2 points as assessed by both the provider and the patient (P < .0001).Additionally, the results are quite impressive, based on photos I have seen, and it appears the agent does not diffuse or spread beyond the area of treatment. While the initial data seem promising, there remain questions of application in other areas and details that could only be gained by phase 3 and 4 studies. I am not an investigator for this agent but I look forward to seeing this added information. FDA approval is extremely unpredictable no matter the strength of the data; your guess as to when approval might occur is as good as mine.