Mycophenolate mofetil (MMF) is a semisynthetic derivative of mycophenolic acid, isolated from the mold Penicillium glaucus. In vitro, it inhibits T- and B-lymphocyte responses, including mito-gen and mixed lymphocyte responses, probably by inhibition ofde novo synthesis of purines. Mycophenolate mofetil is hydrolyzed to mycophenolic acid, the active immunosuppressive moiety; it is synthesized and administered as MMF to enhance bioavailability.
Mycophenolate mofetil is available in both oral and intrave-nous forms. The oral form is rapidly metabolized to mycophenolic acid. Although the cytochrome P450 3A system is not involved, some drug interactions still occur. Plasma drug levels are fre-quently monitored, similar to the calcineurin inhibitors and PSIs.
Mycophenolate mofetil is used in solid organ transplant patients for refractory rejection and, in combination with predni-sone, as an alternative to cyclosporine or tacrolimus in patients who do not tolerate those drugs. Its antiproliferative properties make it the first-line drug for preventing or reducing chronic allograft vasculopathy in cardiac transplant recipients. Myco-phenolate mofetil is used as prophylaxis for and treatment of both acute and chronic graft-versus-host disease in hematopoietic stem cell transplant patients. Newer immunosuppressant applica-tions for MMF include lupus nephritis, rheumatoid arthritis, inflammatory bowel disease, and some dermatologic disorders.
Toxicities include gastrointestinal disturbances (nausea and vomiting, diarrhea, abdominal pain) headache, hypertension, and reversible myelosuppression (primarily neutropenia).