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EMA-approved

Sirolimus — Complete Research Guide (2026)

Last updated 2026-06-30

TL;DR

Sirolimus is a peptide catalogued under Cyclic & Antimicrobial. Neutral reference entry; EU status: EU-approved prescription medicine.

What is Sirolimus?

Sirolimus (rapamycin) is a macrocyclic lactone produced by the bacterium Streptomyces hygroscopicus and acts as an mTOR inhibitor rather than a calcineurin inhibitor.

It is FDA- and EMA-approved for prophylaxis of organ rejection in kidney-transplant recipients, is used to coat drug-eluting coronary stents, and is approved for lymphangioleiomyomatosis.

Its transplant and cardiovascular uses are supported by randomized controlled trials.

How does Sirolimus work?

Sirolimus binds FKBP12, but instead of inhibiting calcineurin the complex inhibits the mechanistic target of rapamycin (mTOR).

This arrests cytokine-driven T-cell proliferation at the G1-to-S phase and also suppresses vascular smooth-muscle proliferation, the basis for its use on coronary stents.

What does the research say about Sirolimus?

  • In the Rapamune US randomized trial, adding sirolimus to a ciclosporin-steroid regimen reduced acute renal-allograft rejection compared with azathioprine. [1]
  • A worldwide phase III trial showed a sirolimus/ciclosporin regimen reduced acute rejection in primary renal-allograft recipients. [2]
  • In the SIRIUS trial, sirolimus-eluting coronary stents markedly reduced restenosis and repeat revascularization versus bare-metal stents. [3]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

  • [1] Efficacy of sirolimus compared with azathioprine for reduction of acute renal allograft rejection: a randomised multicentre study. The Rapamune US Study Group — Kahan BD et al., Lancet 2000. (Randomized controlled trial)
  • [2] A worldwide, phase III, randomized, controlled, safety and efficacy study of a sirolimus/cyclosporine regimen for prevention of acute rejection in recipients of primary mismatched renal allografts — MacDonald AS et al., Transplantation 2001. (Randomized controlled trial)
  • [3] Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery — Moses JW et al., The New England Journal of Medicine 2003. (Randomized controlled trial (SIRIUS))
  • [4] A randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization — Morice MC et al., The New England Journal of Medicine 2002. (Randomized controlled trial (RAVEL))
  • [5] Sirolimus: its discovery, biological properties, and mechanism of action — Sehgal SN et al., Transplantation Proceedings 2003. (Review)

Dosing context

This is not medical advice or a usage recommendation. Dosing figures are reported research context only, cited from the published literature.

This is context only and not dosing guidance: sirolimus for kidney-transplant maintenance is individualized, often using a loading dose followed by once-daily maintenance titrated to whole-blood trough levels.

Therapeutic drug monitoring is recommended, particularly with interacting drugs or hepatic impairment.

Side effects & safety profile

As an immunosuppressant, sirolimus increases the risk of serious infection and of malignancy including lymphoma and skin cancer, consistent with the class boxed warning, and its label additionally warns against use in liver and lung transplantation.

Drug-specific effects include impaired wound healing, hyperlipidaemia (raised cholesterol and triglycerides), mouth ulcers (aphthous stomatitis) and cytopenias.

Blood-level monitoring is used because of its narrow therapeutic index.

Stacking & combinations

In kidney transplantation sirolimus is combined with corticosteroids and either ciclosporin or mycophenolate, and some regimens use it to permit calcineurin-inhibitor minimization or withdrawal.

Finding Sirolimus vendors

Finding Sirolimus vendors

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Frequently asked questions

All three bind an immunophilin, but sirolimus inhibits mTOR rather than calcineurin, blocking cell proliferation instead of early cytokine transcription.

References

  1. [1] Efficacy of sirolimus compared with azathioprine for reduction of acute renal allograft rejection: a randomised multicentre study. The Rapamune US Study Group — Kahan BD et al., Lancet 2000. PMID: 10963197. View sourceStudy: Randomized controlled trialAdding sirolimus instead of azathioprine to ciclosporin-steroid therapy reduced acute rejection in kidney recipients.
  2. [2] A worldwide, phase III, randomized, controlled, safety and efficacy study of a sirolimus/cyclosporine regimen for prevention of acute rejection in recipients of primary mismatched renal allografts — MacDonald AS et al., Transplantation 2001. PMID: 11213073. View sourceStudy: Randomized controlled trialA sirolimus/ciclosporin regimen lowered acute rejection versus placebo in primary renal-allograft recipients.
  3. [3] Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery — Moses JW et al., The New England Journal of Medicine 2003. PMID: 14523139. View sourceStudy: Randomized controlled trial (SIRIUS)Sirolimus-eluting stents reduced restenosis and target-lesion revascularization versus bare-metal stents.
  4. [4] A randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization — Morice MC et al., The New England Journal of Medicine 2002. PMID: 12050336. View sourceStudy: Randomized controlled trial (RAVEL)Sirolimus-eluting stents eliminated measurable restenosis at six months compared with standard stents.
  5. [5] Sirolimus: its discovery, biological properties, and mechanism of action — Sehgal SN et al., Transplantation Proceedings 2003. PMID: 12742462. View sourceStudy: ReviewReviews rapamycin's discovery and its mTOR-mediated mechanism distinguishing it from calcineurin inhibitors.
This article is for educational and research purposes only. Peptides discussed here are not approved for human consumption by the FDA, EMA, or equivalent regulators outside of specific clinical contexts. Always consult a licensed medical professional before any therapeutic use.