Immunosuppressants mycophenolate mofetil

FK-506 (37) interferes with IL-2 synthesis and release and has a cyclosporin-like profile, but is considerably more potent in vitro. IC q values are approximately 100-fold lower. This neutral macroHde suppresses the mixed lymphocyte reaction T-ceU proliferation generation of cytotoxic T-ceUs production of T-ceU derived soluble mediators, such as IL-2, IL-3, and y-IFN and IL-2 receptor expression (83). StmcturaHy, FK-506 is similar to sirolimus. Mycophenolate mofetil (33), brequinar (34), and deoxyspergualin are in various phases of clinical evaluation. Identification of therapeutic efficacy and safety are important factors in the deterrnination of their utiUty as immunosuppressive agents. 

APCs, antigen-producing cells MMF, mycophenolate mofetil OKT-3, muronomab-CD3. (Adapted from Mueller XM. Drug immunosuppressive therapy for adult heart transplantation I. Immune response to allograft and mechanism of action of immunosuppressants. Ann Thorac Surg 2004 77 354-362, with permission.)... 

FIGURE 52-2. Center-specific protocols may use RATG, an IL-2RA, or no induction therapy. In any situation, patients receive IV methylprednisolone prior to, during, or immediately following the transplant operation. The patient then will begin the maintenance immunosuppressive regimen. The center-specific protocol will specify which calcineurin inhibitor (cyclosporine or tacrolimus) is used in combination with mycophenolate mofetil or sirolimus with or without steroids. Patients then are monitored for signs and symptoms of rejection. 

Mycophenolate mofetil was approved by the FDA in 1995, and enteric-coated mycophenolic acid was approved in 2004. Both agents are considered to be adjunctive immunosuppressants. Mycophenolic acid acts by inhibiting inosine monophosphate deydrogenase, a vital enzyme in the de novo pathway of purine synthesis. Inhibition of this enzyme prevents the proliferation of most cells that are dependent on the de novo pathway for purine synthesis, including T cells.7,11,26-28... 

Mycophenolate mofetil is available in 250 mg capsules and 500 mg tablets, an oral suspension (100 mg/mlL, in cherry syrup), and an injectable.11 Usual doses of mycophenolate mofetil range from 1000 to 3000 mg/day in two to four divided doses. The conversion between oral and IV mycophenolate mofetil is 1 1. Enteric-coated mycophenolic acid is available in 180 and 360 mg tablets. For conversion between mycophenolate mofetil and enteric-coated MPA, 1000 mg mycophenolate mofetil is equivalent to 720 mg enteric-coated MPA.26,29 The recommended starting dose of enteric-coated mycophenolic acid is 720 mg given twice daily.11 It appears that conversion of mycophenolate mofetil to enteric-coated mycophenolic acid is safe, but more studies are needed to determine the exact role of enteric-coated MPA in the immunosuppressive armamentarium. Mycophenolic acid trough concentrations can be monitored, but they are not recommended routinely. 

MPA derivatives have replaced azathioprine as the antiproliferative agent of choice in most organ transplant centers. The MPA derivatives generally are considered to provide a more specific immunosuppressive effect compared with azathioprine. Mycophenolate mofetil and enteric-coated mycophe-nolic acid have similar safety and efficacy data in renal transplant recipients. 

Sirolimus is currently the only FDA-approved ToR inhibitor. One of its derivatives, everolimus, is in phase III clinical trials and has been approved for use in some European countries.30 Sirolimus is a macrolide antibiotic that has no effect on cal-cineurin phosphatase.11,31,32 Sirolimus inhibits T cell activation and proliferation by binding to and inhibiting the activation of the mammalian ToR, which suppresses cellular response to IL-2 and other cytokines (i.e., IL-4 and IL-15J.11,31 Studies have shown that sirolimus may be used safely and effectively with either cyclosporine or tacrolimus as a replacement for either azathioprine or mycophenolate mofetil.33 However, when using both sirolimus and cyclosporine as part of a patient s immunosuppressant therapy, because of a drug interaction between the two resulting in a marked increase in sirolimus concentrations, it is recommended to separate the sirolimus and cyclosporine doses by at least 4 hours. Sirolimus also can be used as an alternative agent for patients who do not tolerate calcineurin inhibitors due to nephrotoxicity or other adverse events.34... 

Perez-Aytes A, Ledo A, Boso V, Carey JC, Castell M, Vento M. (2010) Immunosuppressive drugs and pregnancy Mycophenolate mofetil embryopathy. NeoReviews 11 578-589. 

Budde K, Glander P, Grohmann J, Bauer S, Hambach P, Hepburn H, Mai I, Sandau K, Fischer W, Neumayer HH. (2004) Pharmacokinetic and pharmacodynamic comparison of mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) in maintenance renal transplant patients with tacrolimus as basic immunosuppression (P736). Transplantation 78 459 60. 

Mortaiity The use of daclizumab as part of an immunosuppressive regimen including cyclosporine, mycophenolate mofetil, and corticosteroids may be associated with an increase in mortality. 

Cytotoxic agents which are exclusively used to achieve immunosuppression are azathioprine and mycophenolate mofetil, although their over all mechanism of action is similar to that of the antitumor dmgs, i.e. inhibition of lymphocyte proliferation after antigen exposure. 

Mycophenolate mofetil (MMF, CellCept) is an ester prodrug of mycophenolic acid (MPA), a Penicillium-de-rived immunosuppressive agent (see Chapter 57) that blocks de novo purine synthesis by noncompetitively inhibiting the enzyme inosine monophosphate dehydrogenase. MPA preferentially suppresses the proliferation of cells, such as T and B lymphocytes, that lack the purine salvage pathway and must synthesize de novo... 

Selective immunosuppressive agents mycophenolate mofetil sirolimus tacrolimus... 

Drug interactions In a randomized, double-blind study, Zenapax or placebo was added to an immunosuppressive regimen of cyclosporine, mycophenolate mofetil, and steroids to assess tolerability, pharmacokinetics, and drug interactions. The addition of Zenapax did not result in an increased incidence of adverse events or a change in the types of adverse events reported. The following medications have been administered in clinical trials with Zenapax with no incremental increase in adverse reactions cyclosporine, mycophenolate mofetil, ganciclovir, acyclovir, azathioprine, and corticosteroids. 

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 mitogen and mixed lymphocyte responses, probably by inhibition of de 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. 

Sirolimus is used for tissue transplantation where its major advantage over calci-neurin inhibitors is that it is not nephrotoxic. Chronic renal failure in transplant patients who have taken calcineurin inhibitors for the long term can be prevented by the administration of sirolimus. Steroid-free immunosuppression can be achieved by administering sirolimus alone or in combination with mycophenolate mofetil and cyclosporine or tacrolimus. Since impaired wound healing is one of its potential side effects, some transplant centers use sirolimus only after several weeks of surgery. 

Mycophenolic acid (MPA) was isolated from cultures of Penicillium spp. in 1896 and was purified in 1913. Initially the compound was studied for its antifungal and antibacterial effects and later for its antitumor effects. Many years later, its immunosuppressive activities were recognized and after further developmental work, an ester prodrug mycophenolate mofetil was developed, which was approved by the United States Food and Drug Administration for the prevention of acute renal allograft rejection in 1995 and for heart transplant recipients in 1998. Mycophenolate mofetil is a cytotoxic agent now used for immunosuppressive therapy and is the mofetil ester of MPA, which is the active immunosuppressive agent. 

Boratynska M, Banasik M, Patrzalek D, Klinger M. 2006. Conversion from cyclosporine-based immunosuppression to tacrolimus/mycophenolate mofetil in patients with refractory and ongoing acute renal allograft rejection. Ann Transplant. 11 51-56. 

Tanabe K, Tokumoto T, Ishida H, Ishikawa N, et al. 2004. Excellent outcome of ABO-incompatible living kidney transplantation under pre transplantation immunosuppression with tacrolimus, mycophenolate mofetil and steroid. Transpl Proc. 36 2175-2177. 

Daclizumab is used for the prophylaxis of acute rejection in patients receiving kidney transplants. A dose of 1 mg/kg is sufficient to completely block all the IL-2 receptors. It is administered in five doses at a 2-week interval where its elimination half-life is about 20 days. A combination of several other immunosuppressive agents including cyclosporine (or tacrolimus, rapamycin), mycophenolate mofetil and corticosteroids can be used with daclizumab. When it is used in combination with tacrolimus, the doses of tacrolimus are reduced. After tissue transplantation, the addition of daclizumab to the standard immunosuppressive regimen produces reduction in tissue rejection up to 50%. Daclizumab can cause hypersensitivity reactions, but it does not cause cytokine-release syndrome. There is a low incidence of... 

A 59-year-old woman taking pravastatin 20 mg/day tolerated immunosuppression with ciclosporin, prednisone, and mycophenolate mofetil for 4 years after heart transplantation. After switching from pravastatin to simvastatin she developed severe muscle weakness and laboratory evidence of muscle breakdown. The biochemical markers of rhabdomyolysis did not normalize until after repeat hemodialysis. Clinical improvement did not occur until after 5 months. 

Gomez E, Aguado S, Rodriguez M, Alvarez-Grande J. Kaposi s sarcoma after renal transplantation—disappearance after reduction of immunosuppression and reappearance 7 years later after start of mycophenolate mofetil treatment. Nephrol Dial Transplant 1998 13(12) 3279-80. 

Clinical Use. Mycophenolate mofetil (CellCept) is primarily used to prevent or treat organ rejection following cardiac and renal transplantation. This drug is typically combined with other immunosuppressants (cyclosporine, glucocorticoids) to provide optimal immunosuppression in patients receiving these transplant types.39,40,70 Mycophenolate mofetil may also be useful in suppressing the immune response associated with autoimmune conditions such as systemic lupus erythematosus.2... 

Mycophenolic acid (Figure 3.36) is produced by fermentation cultures of the fungus Penicillium brevicompactum. It has been known for many years to have antibacterial, antifungal, antiviral, and antitumour properties. It has recently been introduced into medicine as an immunosuppressant drug, to reduce the incidence of rejection of transplanted organs, particularly kidney and heart transplants. It is formulated as the /V-morpholinoethyl ester mycophenolate mofetil (Figure 3.37), which is metabolized after ingestion to mycophenolic... 

Keywords Acetylcholine Autonomic nervous system Cyclosporine Epinephrine General anesthetics Immunostimu-lating agents Immunosuppressive agents Mycophenolate mofetil Opioid drugs Sedative-hypnotic agents... 

Mycophenolate mofetil Esterification of the immunosuppressive agent mycophenolic add (MMA) leads to mycophenolate mofetil (MME) as a prodrug with improved oral bioavailability. MMF (2 g/day) was first administered in PBC, combined with UDCA, by E.A. Jones et al. in 1999. In a later study, they were able to confirm thdr good results (based on selectively and reversibly inhibiting... 

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