Improving Human Life by Advancing the Field of Transplantation

The use of generic tacrolimus poses an interesting dilemma to the transplant community. As opposed to mycophenolate, a non-nephrotoxic drug with excellent and for most predictable bioavailability, tacrolimus has a narrow therapeutic window, and a more variable pharmacokinetic profile. In contrast to some generic preparations of cyclosporine – no pharmacokinetic studies of generic tacrolimus have been carried out in American transplant patients. Since the Food and Drug Administration only requires testing of generic drugs in healthy subjects for approval, performance of clinical pharmacological studies in our transplant patients will not happen.

The paucity of data upon which to base a safe decision making is particularly concerning in the light of a post-hoc analysis of a 3-year randomized, open-label controlled study conducted in Mexico and presented at the 22nd International Congress of the Transplantation Society in August 20081. In this study, primary kidney transplant recipients treated with a generic tacrolimus preparation (Tenacrine) had a greater incidence of acute rejection than their counterparts treated with Prograf®. Mean tacrolimus blood levels were lower in patients treated with the generic form at 3, 6, and 9 months post-transplant when compared with baseline (P < 0.05)1.

Notwithstanding our trepidation, in the current environment of health care reform and cost-containment, private insurance companies will soon impose high co-pay rates on Prograf thereby limiting its access to our patients, and physicians will be left with few options other than a close follow-up of those patients switching agents and hope for the best possible outcome.

Reference:
1)Holm Corzo A et al: A Post-Hoc Analysis of the Safety and Efficacy of Tacrolimus (Prograf) Versus a Generic Formulation of Tacrolimus (Tenacrine) as Primary Immunosuppressive Therapy in LRD and CAD Adults and Pediatric Renal Transplant Recipients [Mini-Oral Session 18 WMO18]
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