MYFORTIC

What it is

Myfortic is an enteric-coated tablet containing mycophenolic acid as the sodium salt, available in strengths of 180 mg and 360 mg. Mycophenolic acid is a non-nucleoside, non-competitive, reversible inhibitor of inosine monophosphate dehydrogenase, the rate-limiting enzyme in the de novo synthesis pathway of guanosine triphosphate, and selectively decreases the lymphocyte nucleotide pool to impair the capacity of T- and B-lymphocytes to proliferate.

Approved indications

— Prophylaxis of acute transplant rejection in adult patients receiving allogeneic renal transplants. — Induction and maintenance treatment of adult patients with WHO Class III, IV or V lupus nephritis.

Dosing overview

For renal transplant patients, the recommended dose is 720 mg administered twice daily (1440 mg daily dose). For lupus nephritis patients, the recommended dose is also 720 mg administered twice daily (1440 mg daily dose). The dose may be tapered for maintenance purposes following a complete or partial response in lupus nephritis. Myfortic tablets should not be crushed and should be swallowed whole. Patients should be advised to take Myfortic consistently either with or without food, but not switch between fed and fasted states because of the risk of increased MPA AUC variability.

Key safety warnings

Myfortic can cause foetal harm when administered to a pregnant woman; use during pregnancy is associated with an increased risk of pregnancy loss including spontaneous abortion and an increased risk of congenital malformations, especially external ear and other facial abnormalities including cleft lip and palate, and anomalies of the distal limbs, heart, oesophagus, and kidney. Patients receiving immunosuppressive regimens involving combinations of drugs, including Myfortic, are at increased risk of developing lymphomas and other malignancies, particularly of the skin; the risk appears to be related to the intensity and duration of immunosuppression rather than to the use of any specific agent. To minimise the risk for skin cancer, exposure to sunlight and UV light should be limited by wearing protective clothing and using a sunscreen with a high protection factor. Oversuppression of the immune system increases the susceptibility to infection, including opportunistic infections, fatal infections and sepsis. Cases of progressive multifocal leukoencephalopathy, sometimes fatal, have been reported in patients treated with MPA derivatives; hemiparesis, apathy, confusion, cognitive deficiencies and ataxia were the most frequent clinical features observed. Reactivation of hepatitis B or hepatitis C have been reported in patients treated with immunosuppressants, including mycophenolic acid derivatives; monitoring infected patients for clinical and laboratory signs of active HBV or HCV infection is recommended. Patients taking Myfortic should have complete blood counts weekly during the first month, twice monthly for the second and third months of treatment, then monthly through the first year; if blood dyscrasias such as neutropenia with absolute neutrophil count <1.5 × 10⁹/L or anaemia occur, it may be appropriate to interrupt or discontinue Myfortic.

Contraindications

Myfortic is contraindicated in pregnancy unless there is no suitable alternative treatment to prevent transplant rejection. Myfortic is contraindicated in women who are breast-feeding and in women of child-bearing potential who are not using highly effective contraception methods and should not be initiated without providing a pregnancy test to rule out unintended pregnancy. It is also contraindicated in patients with a hypersensitivity to mycophenolate sodium, mycophenolic acid or mycophenolate mofetil or to any of the excipients of the formulation.

Regulatory history

Myfortic 180 mg and 360 mg enteric-coated tablets were first listed on the Australian Register of Therapeutic Goods on 25 March 2003 and 26 March 2003 respectively.