Replies to post #2919 on Revance Therapeutics Inc (RVNC)

[DewDiligence]

Re: Botox’s median duration

There is no pure apples-to-apples comparison I’m aware of because Botox’s phase-3 trials for glabellar lines used a different metric for the patient’s self-assessment. From page 2 of the FDA label for Botox Cosmetic:

Two phase 3 randomized, multi-center, double blind, placebo-controlled studies of identical design were conducted to evaluate BOTOX Cosmetic for use in the temporary improvement of the appearance of moderate to severe glabellar facial lines. … The co-primary efficacy endpoints were the investigator’s rating of glabellar line severity at maximum frown and the subject’s global assessment of change in appearance of glabellar lines, both at Day 30 post-injection.

For the investigator rating, using a 4-point grading scale (0=none, 3=severe) a responder was defined as having a severity grade of 0 or 1. For the subject’s global assessment of change, the ratings were from +4 (complete improvement) to -4 (very marked worsening). A responder was defined as having a grade of at least +2 (moderate improvement).

Emphasis added. So, the metric used for the Botox investigator’s assessment is the same as the one used in RVNC’s SAKURA trials, but the metric used for the Botox patient’s self-assessment is radically different from the one used in the SAKURA trials, making an apples-to-apples comparison unworkable.

Fortunately, we can glean some information from the FDA label for Botox Cosmetic. Page 11 of the label says “the duration of activity…is approximately 3-4 months.” I.e., it’s safe to say that Botox’s median duration wouldn’t exceed four months even if the duration were calculated using the most flattering evaluation metric.

Last but not least, there is widespread agreement among patients and injectors that Botox lasts about three months, and I’ve yet to hear anybody claim that Botox’s median duration is longer than that.