Treatment optimization of maintenance immunosuppressive agents in pediatric renal transplant recipients

Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.

Immunosuppression with generic tacrolimus in liver and kidney transplantation-systematic review and meta-analysis on biopsy-proven acute rejection and bioequivalence

While rejection prevention with innovator tacrolimus (Tac) is one of the key factors for long-lasting graft function, the use of generic Tac is still under debate. Thus, we performed a systematic review and meta-analysis to provide an overview on the current body of evidence for the effect of generic Tac in adult liver (LT) and kidney transplantation (KT) with focus on both biopsy-proven acute rejection (BPAR) and bioequivalence. A systematic literature search for trials comparing generic versus innovator Tac was conducted accordingly. Seventeen studies (5 LT, 11 KT, 1 LT/KT) including 1412 patients were identified. About 92.9% (13/14; 5/5 LT, 8/9 KT) of studies reported the same or lower BPAR with generics (pooled RR: 0.84, 95% CI: 0.65-1.09); however, de novo studies showed a significantly lower risk with generic Tac (RR: 0.75, 95% CI: 0.63-0.90), whereas conversion studies showed increased risk (RR: 1.93, 95% CI: 1.00-3.70). Bioequivalence was demonstrated primarily in studies on conversion. The current evidence is mostly based on observational data and studies showing some risk of bias. In conclusion, whereas overall there was no significant difference in terms of BPAR, there is some evidence suggesting lower BPAR risk with generic Tac for de novo use.

Original and generic preservation solutions in organ transplantation. A new paradigm?

Solid organ transplantation is a very complex process, in which the storage of the graft in a preservation solution is mandatory in order to extend ischemic times and contain further damage. The condition in which the organ is transplanted is critical for the outcome of the organ recipient. The recent emergence of generic versions of organ preservation solutions (solutions with the same composition and under the same legislation as the original versions, but with different brands) compelled us to study whether the standards are maintained when comparing the original and its generic counterpart. Along these lines, we discuss and comment on some aspects concerning this issue of general interest in the organ transplantation field.

The adoption of generic immunosuppressant medications in kidney, liver, and heart transplantation among recipients in Colorado or nationally with Medicare part D

The transplant community is divided regarding whether substitution with generic immunosuppressants is appropriate for organ transplant recipients. We estimated the rate of uptake over time of generic immunosuppressants using US Medicare Part D Prescription Drug Event (PDE) and Colorado pharmacy claims (including both Part D and non-Part D) data from 2008 to 2013. Data from 26 070 kidney, 15 548 liver, and 6685 heart recipients from Part D, and 1138 kidney and 389 liver recipients from Colorado were analyzed. The proportions of patients with PDEs or claims for generic and brand-name tacrolimus or mycophenolate mofetil were calculated over time by transplanted organ and drug. Among Part D kidney, liver, and heart beneficiaries, the proportion dispensed generic tacrolimus reached 50%-56% at 1 year after first generic approval and 78%-81% by December 2013. The proportion dispensed generic mycophenolate mofetil reached 70%-73% at 1 year after generic market entry and 88%-90% by December 2013. There was wide interstate variability in generic uptake, with faster uptake in Colorado compared with most other states. Overall, generic substitution for tacrolimus and mycophenolate mofetil for organ transplant recipients increased rapidly following first availability, and utilization of generic immunosuppressants exceeded that of brand-name products within a year of market entry.