 Patients will be treated for approximately 28 days and return to the clinic weekly for safety and efficacy assessments. The investigator will stop study treatment if a patient achieves clinical cure by or after the 3rd treatment visit approximately study day 15. After completing treatment, patients will return to the clinic for scheduled follow-up visits or until ulcer closure. The final efficacy assessments used in the primary efficacy analyses will be obtained at the first follow-up visit approximately 10 days after treatment is stopped. The remaining follow-up visits will occur at approximately 30, 60 and 90 days after treatment is stopped when patients will be assessed for ulcer closure and any re-infection. 