{"entity":{"id":"sirolimus","kind":"drug","name":"Sirolimus","aka":["Rapamycin"],"tldr":"Sirolimus is an anti-rejection tablet taken after an organ transplant. Switching to it from a calcineurin inhibitor roughly halves the number of new skin squamous cell carcinomas in people who have already had one, at the cost of more side effects and a quarter of people stopping it.","summary":"Sirolimus, first isolated from a soil bacterium on Rapa Nui and originally an antifungal, was approved by the FDA in 1999 to prevent rejection of a kidney transplant. It is not a cancer drug and has no cancer indication; it belongs to this family because of what switching to it does to skin cancer risk.\n\nTUMORAPA randomised 120 kidney transplant recipients who had already had one cutaneous squamous cell carcinoma either to switch from a calcineurin inhibitor to sirolimus or to carry on. New squamous cell carcinomas occurred in 22 per cent against 39 per cent, a relative risk of 0.56 (95 per cent confidence interval 0.32 to 0.98), with the median time to the next cancer moving from 7 to 15 months and graft function stable in both arms. The cost was 60 serious adverse events against 14 and 23 per cent stopping the drug, and switching rapidly caused twice as many serious events as switching gradually. That trade is why the switch is discussed rather than made automatically.\n\nSirolimus is also the drug the immunosuppression is cross-tapered to before a transplant recipient is given PD-1 blockade for advanced disease, which is how the Dana-Farber study avoided rejection. Two related records exist in the corpus: temsirolimus, its intravenous ester, and albumin-bound sirolimus, which is licensed for perivascular epithelioid cell tumour.","status":"approved","asOf":"2026-09-25","wikipedia":"https://en.wikipedia.org/wiki/Sirolimus","links":[{"label":"Euvrard et al., sirolimus and secondary skin-cancer prevention in kidney transplantation, TUMORAPA (New England Journal of Medicine 2012)","url":"https://doi.org/10.1056/NEJMoa1204166"},{"label":"DailyMed: Rapamune (sirolimus) prescribing information","url":"https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=RAPAMUNE"},{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Sirolimus"}],"tags":["skin"],"related":["temsirolimus","sirolimus-albumin-bound","cemiplimab"],"cancers":["cutaneous-scc","skin-cancer","advanced-cutaneous-scc"],"sections":[],"technologies":[],"targets":["mtor"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["skin-cancer-after-organ-transplant"],"trials":["tumorapa","cemiplimab-kidney-transplant-cscc"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"brand":"Rapamune","modality":"Oral mammalian target of rapamycin (mTOR) inhibitor, used as an immunosuppressant","mechanism":"Binds FKBP12; the complex inhibits mTOR complex 1, blocking the interleukin-2 signal that drives lymphocyte proliferation. The same inhibition slows tumour cell growth and angiogenesis, which is why an anti-rejection drug has an antitumour effect.","approvals":[{"region":"US","year":1999,"indication":"Prophylaxis of organ rejection in kidney transplant recipients"}],"mechanismSteps":[],"toxicity":[],"access":[],"regulatoryEvents":[]},"route":"/drugs/sirolimus/","neighbours":{"drug":[{"id":"cemiplimab","kind":"drug","name":"Cemiplimab","route":"/drugs/cemiplimab/"},{"id":"sirolimus-albumin-bound","kind":"drug","name":"Sirolimus protein-bound particles","route":"/drugs/sirolimus-albumin-bound/"},{"id":"temsirolimus","kind":"drug","name":"Temsirolimus","route":"/drugs/temsirolimus/"}],"cancer":[{"id":"advanced-cutaneous-scc","kind":"cancer","name":"Advanced cutaneous squamous cell carcinoma","route":"/cancers/advanced-cutaneous-scc/"},{"id":"cutaneous-scc","kind":"cancer","name":"Cutaneous squamous cell carcinoma","route":"/cancers/cutaneous-scc/"},{"id":"skin-cancer","kind":"cancer","name":"Skin cancer (all types)","route":"/cancers/skin-cancer/"}],"target":[{"id":"mtor","kind":"target","name":"mTOR","route":"/targets/mtor/"}],"term":[{"id":"skin-cancer-after-organ-transplant","kind":"term","name":"Skin cancer after an organ transplant","route":"/terms/skin-cancer-after-organ-transplant/"}],"trial":[{"id":"cemiplimab-kidney-transplant-cscc","kind":"trial","name":"Cemiplimab for kidney transplant recipients with advanced skin squamous cell carcinoma","route":"/trials/cemiplimab-kidney-transplant-cscc/"},{"id":"tumorapa","kind":"trial","name":"TUMORAPA (switching from a calcineurin inhibitor to sirolimus after a transplant skin cancer)","route":"/trials/tumorapa/"}]}}