What is "sirolimus"

n. (context pharmacy English) The drug rapamycin.

Sirolimus ( INN/ USAN), also known as rapamycin, is a macrolide compound produced by the bacterium Streptomyces hygroscopicus that is used in medicine to prevent organ transplant rejection and to treat lymphangioleiomyomatosis. It has immunosuppressant functions in humans and is especially useful in preventing the rejection of kidney transplants. It inhibits activation of T cells and B cells by reducing the production of interleukin-2 (IL-2). Sirolimus is also used as a coating for coronary stents.

Sirolimus was isolated for the first time in 1972 by Suren Sehgal and colleagues from samples of Streptomyces hygroscopicus found on Easter Island. The compound was originally named rapamycin after the native name of the island, Rapa Nui. Sirolimus was initially developed as an antifungal agent. However, this use was abandoned when it was discovered to have potent immunosuppressive and antiproliferative properties due to its ability to inhibit mTOR. It was approved by the US Food and Drug Administration in September 1999 and is marketed under the trade name Rapamune by Pfizer (formerly by Wyeth).