Product name: Sirolimus

CAS: 53123-88-9

Molecular formula: C51H79NO13

Molecular weight: 914.18

Description: Sirolimus , also known as rapamycin, is an immunosuppressant drug used to prevent rejection in organ transplantation; it is especially useful in kidney transplants. It prevents activation of T cells and B cells by inhibiting their response to interleukin-2 (IL-2). Sirolimus is also used as a coronary stent coating. Sirolimus works, in part, by eliminating old and abnormal white blood cells.[citation needed] Sirolimus is effective in mice with autoimmunity and in children with a rare condition called autoimmune lymphoproliferative syndrome (ALPS).

A macrolide, sirolimus was discovered by Brazilian researchers as a product of the bacterium Streptomyces hygroscopicus in a soil sample from Easter Island — an island also known asRapa Nui. It was approved by the FDA in September 1999 and is marketed under the trade name Rapamune by Pfizer (formerly 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.