Rapamycin Dose-Ranging Efficacy Study in Port Wine Stains

This is a single-centre, double-blind, randomized withdrawal design, parallel group, placebo-controlled, dose-response clinical study investigating the efficacy and safety of two concentrations of topical rapamycin cream in the treatment of port wine stain as an adjunct to pulsed dyed laser (PDL) in paediatric patients. 30 participants will be enrolled into the study. The study hypothesis is that topical rapamycin, as an adjunct to PDL, will show a dose-dependent increase in the blanching of port wine birthmarks, compared to PDL with placebo after 12 weeks. Eligible participants will undergo PDL treatment of their entire port wine birthmark. Patients that respond positively to PDL within 5 days will be enrolled and randomized, before the first application of the study drug. Participants will be randomly assigned to one of three possible treatments in a 1:1:1 ratio: * Rapamycin cream, topical (0.6% rapamycin) * Rapamycin cream, topical (1.0% rapamycin) * Placebo The stain will be divided into two parts. One part will be treated only with PDL and the other will be treated with both PDL and the assigned cream. Cream will be applied once daily for 12 weeks. During this phase of the study, four clinical visits will occur, one every 4 weeks for 12 weeks. Assessment of the extent and severity of birthmark size and colour will be performed at randomization, at each clinical visit, and at follow-up using photography and percentage improvement ratings. Safety will be assessed by recording all adverse events experienced and testing blood rapamycin concentration at prior to treatment and at the last clinical visit. Follow-up will be performed 28 days after the last cream application. An extra PDL session will be optionally provided at the follow-up appointment. If PDL treatment occurs at the follow-up visit, a further follow-up phone call will occur 7±2 days after the second PDL session to assess concomitant medications and adverse events.