sirolimus + daclizumab + mycophenolate mofetil + corticosteroids

A four-drug **immunosuppressive regimen** combining sirolimus, daclizumab, mycophenolate mofetil, and corticosteroids, primarily used in organ transplantation to prevent acute rejection. - **Sirolimus** is an mTOR inhibitor that suppresses lymphocyte activation and proliferation. - **Daclizumab** is a monoclonal antibody targeting the interleukin-2 receptor alpha chain (CD25), blocking T-cell activation. - **Mycophenolate mofetil** is an immunosuppressive antimetabolite that inhibits inosine monophosphate dehydrogenase in lymphocytes, thereby blocking purine synthesis and T- and B-cell proliferation. - **Corticosteroids** are anti-inflammatory and immunosuppressive agents that broadly suppress immune response via glucocorticoid receptor agonism and transcriptional regulation of many pro-inflammatory genes. This combination was used in renal and heart transplantation as a calcineurin inhibitor-free regimen to reduce the incidence of graft rejection and limit calcineurin inhibitor-related toxicity. Clinical studies showed increased exposure to mycophenolic acid, variable efficacy, and typical immunosuppression side effects. Daclizumab has been withdrawn from the market.