Mammalian target of rapamycin inhibitors in heart transplantation what we know and do not know?

Assessing the cost-effectiveness of replacing antimetabolites with mTOR inhibitors in heart transplant immunosuppression in China: a network meta-analysis-based economic evaluation

BACKGROUND

Although several pharmacoeconomic studies have assessed the cost-effectiveness of maintenance immunosuppressive regimens for heart transplant recipients, economic comparisons between various combination drug therapies remain sparse.

AIM

This study used an economic evaluation based on network meta-analysis to assess the cost-effectiveness of four immunosuppressive regimens for adult heart transplant recipients in China.

METHOD

We conducted a systematic search for clinical trials in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Data, and VIP database. A validated Markov model was adapted to reflect the Chinese medical landscape. Four maintenance immunosuppression regimens were considered: tacrolimus/mycophenolate mofetil (TAC/MMF), cyclosporine/mycophenolate mofetil (CSA/MMF), everolimus/cyclosporine (EVL/CSA), and sirolimus/tacrolimus (SRL/TAC). The probabilities of health events were derived from a comprehensive literature review. Direct medical costs, adjusted for 2022 values, were from public documents and websites, while utilities for quality-adjusted life-years (QALYs) were taken from previous studies. Primary outcomes were mean lifetime cost, QALYs, and cost-effectiveness, with a willingness-to-pay (WTP) threshold set at three times China's GDP per capita in 2022. Sensitivity analyses were conducted to test the robustness of the results.

RESULTS

The base case analysis identified TAC/MMF as the most cost-effective regimen, producing a mean of 6.31 QALYs per patient at a cost of Chinese Yuan (CNY) 534,182.89. Sensitivity analyses consistently reinforced TAC/MMF as the most cost-effective and robust choice.

CONCLUSION

TAC/MMF is the most cost-effective maintenance immunosuppressive regimen for heart transplant recipients within the Chinese health system. The study findings are reinforced by sensitivity analyses, affirming their robustness amid various uncertainties.

BEZ235 Prolongs Murine Cardiac Allograft Survival Through the Autophagy Pathway

BACKGROUND

BEZ235, a dual PI3K/mTOR inhibitor, has shown a critical impact in the treatment of cancers, with the ability to induce autophagy. However, the effects of BEZ235 in heart transplant have been rarely investigated. The aim of this study was to evaluate the potency of BEZ235 in cardiac allograft survival.

METHODS

BEZ235 was administered during the perioperative period of syngeneic or allogeneic heart transplant to assess survival time. Next, the autophagy signaling pathway and the proinflammatory cytokines were analyzed. Furthermore, a cardiomyocytes-specific ATG5 gene-ablated mouse was used to confirm the results.

RESULTS

BEZ235 treatment significantly prolonged the survival of the cardiac graft and reduced the infiltration of inflammatory cells. The expression levels of autophagy proteins were increased in the BEZ235 treatment group compared to the control group, but the therapeutic effect of BEZ235 was weakened in the cardiomyocytes-specific ATG5 gene-ablated mice. Moreover, BEZ235 significantly downregulated the expression of IL-1β, IL-2, and TNF-α.

CONCLUSIONS

It seems BEZ235 could induce autophagy and prolonged murine cardiac allograft survival in a mechanism that involved the autophagy pathway and changed multiple inflammatory factors. This study has proposed a theoretical foundation for the strong connection between mTOR-induced autophagy and heart transplant.