The purpose of this a randomized withdrawal Phase III, multi-center research study is to evaluate the safety and effectiveness of repeat treatment with an intramuscular dose of Mentor Purified Toxin in the reduction of glabellar rhytides (frown lines). Approximately 700 subjects will be enrolled at approximately 12 clinical sites in the U.S.A.~Effectiveness will be determined by the degree of frown line reduction, during maximum forced frown and at rest (neutral expression):~as assessed live by the study doctor,~as assessed live by the subject, and;~as assessed by an independent reviewer based on subject photographs~Frown lines are graded on level of severity based on this scale:~Severity~Minimal (0)~Mild (1)~Moderate (2)~Severe (3)~There are two parts to this study. In the first part, all study participants will receive treatment with an intramuscular injection of 30 Units of Mentor Purified Toxin on two separate occasions (Cycles 1 and 2) no more than 6 months apart. In the second part of the study (Cycle 3), subjects will be randomly assigned to receive either intramuscular injections of 30 Units of Mentor Purified Toxin or placebo (preservative-free saline) and subjects will be followed for 1 month (3:1, PurTox : placebo).~Each subject will receive five intramuscular injections for a total of 0.5 mL of study drug in the glabellar area, during each treatment visit. Participation takes place over a maximum of 14 months, including Part 1 (Cycle 1 and 2) and Part 2 (Cycle 3). The number of clinic visits will vary from person to person depending upon the subject's response to the study drug, but will range from approximately 9 to 19 clinic visits. There will also be up to 4 telephone follow-up contacts.
The overall purpose of this study is to evaluate the safety and effectiveness of repeat treatment of an intramuscular dose of Mentor Purified Toxin for the reduction of frown lines, compared with placebo.