Weekly pill could tame painful birthmarks with fewer side effects

This study tests whether taking the drug sirolimus just once a week can safely treat venous and lymphatic malformations—abnormal clusters of blood vessels or lymph vessels that can cause pain and swelling. Current daily dosing works but often causes side effects like low white blood cell counts and mouth sores. The trial will enroll 24 people aged 2 and older, who will take sirolimus weekly for 6 months, with the option to continue longer. Researchers will measure changes in lesion size and track side effects to see if weekly dosing is a good alternative.