Last reviewed 2026-04-20 · How we verify

SIROLIMUS

Sirolimus binds to FKBP-12 to form a complex that inhibits mTOR, blocking T-cell proliferation and antibody production.

At a glance

Mechanism of action

Sirolimus works by binding to a protein called FKBP-12, forming a complex that inhibits the mTOR pathway. This prevents T-cells from multiplying and producing antibodies, which helps prevent organ rejection and treat autoimmune diseases.

Approved indications

No approved indications tracked.

Boxed warnings

• WARNING: IMMUNOSUPPRESSION, USE IS NOT RECOMMENDED IN LIVER OR LUNG TRANSPLANT PATIENTS Increased susceptibility to infection and the possible development of lymphoma and other malignancies may result from immunosuppression Increased susceptibility to infection and the possible development of lymphoma may result from immunosuppression. Only physicians experienced in immunosuppressive therapy and management of renal transplant patients should use sirolimus for prophylaxis of organ rejection in patients receiving renal transplants. Patients receiving the drug should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources. The physician responsible for maintenance therapy should have complete information requisite for the follow-up of the patient [ see Warnings and Precautions ( 5.1 ) ]. The safety and efficacy of sirolimus as immunosuppressive therapy have not been established in liver or lung transplant patients, and therefore, such use is not recommended [ see Warnings and Precautions ( 5.2 , 5.3 ) ]. Liver Transplantation – Excess Mortality, Graft Loss, and Hepatic Artery Thrombosis (HAT) The use of sirolimus in combination with tacrolimus was associated with excess mortality and graft loss in a study in de novo liver transplant patients. Many of these patients had evidence of infection at or near the time of death. In this and another study in de novo liver transplant patients, the use of sirolimus in combination with cyclosporine or tacrolimus was associated with an increase in HAT; most cases of HAT occurred within 30 days post-transplantation and most led to graft loss or death [ see Warnings and Precautions ( 5.2 ) ]. Lung Transplantation – Bronchial Anastomotic Dehiscence Cases of bronchial anastomotic dehiscence, most fatal, have been reported in de novo lung transplant patients when sirolimus has been used as part of an immunosuppressive regimen [ see Warnings and Precautions ( 5.3 ) ]. WARNING: IMMUNOSUPPRESSION, USE IS NOT RECOMMENDED IN LIVER OR LUNG TRANSPLANT PATIENTS See Full Prescribing Information for Complete Boxed Warning . Increased susceptibility to infection and the possible development of lymphoma and other malignancies may result from immunosuppression ( 5.1 ). Only physicians experienced in immunosuppressive therapy and management of renal transplant patients should use sirolimus for prophylaxis of organ rejection in patients receiving renal transplants. The safety and efficacy of sirolimus as immunosuppressive therapy have not been established in liver or lung transplant patients, and therefore, such use is not recommended ( 5.2 , 5.3 ). − Liver Transplantation – Excess mortality, graft loss, and hepatic artery thrombosis ( 5.2 ). − Lung Transplantation – Bronchial anastomotic dehiscence ( 5.3 ).

Common side effects

• peripheral edema
• hypertriglyceridemia
• hypertension
• hypercholesterolemia
• creatinine increased
• abdominal pain
• diarrhea
• headache
• fever
• urinary tract infection
• anemia
• nausea

Key clinical trials

• A Phase 2, Baseline-Controlled Study Evaluating the Safety and Efficacy of PTX-022 (Sirolimus) Topical Gel 3.9% in the Treatment of Cutaneous Venous Malformations (PHASE2)
• Pilot Trial of Allogeneic Blood or Marrow Transplantation for Primary Immunodeficiencies (PHASE2)
• Testing Lutetium Lu 177 Dotatate in Patients With Somatostatin Receptor Positive Advanced Bronchial Neuroendocrine Tumors (PHASE2)
• Comparing Retreatment of 177Lu-DOTATATE PRRT Versus the Usual Treatment in Patients With Metastatic Unresectable Gastroenteropancreatic Neuroendocrine Tumors, NET RETREAT Trial (PHASE2)
• Virotherapy and Natural History Study of KHSV-Associated Multricentric Castleman s Disease With Correlates of Disease Activity (PHASE2)
• Part B- G1X-CGD (Lentiviral Vector Transduced CD34+ Cells) in Patients With X-Linked Chronic Granulomatous Disease (PHASE1, PHASE2)
• Combination Chemotherapy With or Without Temsirolimus in Treating Patients With Intermediate Risk Rhabdomyosarcoma (PHASE3)
• SELVA: A Phase 3 Study Evaluating QTORIN 3.9% Rapamycin Anhydrous Gel in the Treatment of Microcystic Lymphatic Malformations (PHASE3)

Primary sources

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