Is There Evidence to Support Brand to Generic Interchange of the Mycophenolic Acid Products?

ABSTRACT

The uptake of generic immunosuppressants lags comparatively to other drug classes, despite that the Food and Drug Administration (FDA) uses identical bioequivalence standards for all drugs. Transplant societies acknowledge the cost savings associated with generic immunosuppressants and support their use following heart, lung, kidney, or bone marrow transplantation. Seven studies of the pharmacokinetics or clinical efficacy of generic mycophenolate mofetil compared to the innovator product are published; all studies and products were ex-United States. Three studies did not demonstrate any pharmacokinetic differences between generic and innovator products in healthy subjects, achieving FDA bioequivalence requirements. Two studies in renal allograft recipients demonstrated no difference in area under the curves between generic and innovator products, and in one, the maximum concentration (Cmax) fell outside the FDA regulatory range. Two studies revealed no difference in acute organ rejection or graft function in renal allograft recipients. Patient surveys indicate that cost is a barrier to immunosuppressant adherence. Generics present a viable method to reduce costs to payers, patients, and health care systems. Adherence to immunosuppressants is crucial to prevent graft failure. An affordable regimen potentially confers greater adherence. Concerns regarding the presumed inferiority of generic immunosuppressants should be assuaged by regulatory requirements for bioequivalency testing, transplant society position statements, and pharmacokinetic and clinical studies.