What is Rapamycin
Rapamycin also known as sirolimus, is an immunosuppressant drug used to prevent rejection in organ transplantation; it is especially useful in kidney transplants. A macrolide, sirolimus was first discovered as a product of the bacterium Streptomyces hygroscopicus in a soil sample from Easter Island— an island also known as Rapa Nui, hence the name. It is marketed under the trade name Rapamune by Wyeth.
Sirolimus was originally developed as an antifungal agent. However, this use was abandoned when it was discovered to have potent immunosuppressive and antiproliferative properties. It has since been shown to prolong the life of mice and might also be useful in the treatment of certain cancers.