Mycophenolate mofetil versus azathioprine in kidney transplant recipients on steroid-free, low-dose cyclosporine immunosuppression (ATHENA): A pragmatic randomized trial

Conversion to tacrolimus alone compared to full immunosuppression following cardiac transplantation (TACTFUL)

BACKGROUND

Cardiac transplantation requires lifelong immunosuppressant medications to prevent rejection. However, some patients may not tolerate multiple immunosuppressants due to adverse effects. At our institution, patients may be converted to monotherapy with tacrolimus if unable to tolerate a combination regimen. This study evaluated the outcomes among patients converted to tacrolimus monotherapy compared with those maintained on combination immunosuppression.

METHODS

This single-center, retrospective cohort study included patients who received heart transplants at Sentara Norfolk General Hospital between January 2015 and July 2021. Patients were classified as receiving tacrolimus monotherapy (Mono) or combination immunosuppression (Combo). The primary outcome was all-cause mortality with key secondary outcomes including incidence of 2R/3R rejection, necessity for renal replacement therapy, and infection.

RESULTS

112 patients were included (Mono = 25, Combo = 87). Median age at transplant was 53.8 years (Mono) and 52.1 years (Combo). The most common reasons for conversion to monotherapy were leukopenia, infection, and gastrointestinal (GI) distress. There was no difference in mortality (0 in Mono, 11 in Combo; p = .09) or percentage of patients with 2R/3R rejection (24% in Mono, 32.2% in Combo; p = .43). No Mono group patients experienced rejection after converting from combination therapy. 24% of Mono group patients resumed at least one additional immunosuppressive medication during the study period. Median time to monotherapy was 9.0 months, with a total median duration on monotherapy of 16.0 months. A median of 3.3 years of follow-up was observed for patients in Mono and 3.4 years in Combo (p = .29).

CONCLUSION

Selected patients who do not tolerate combination immunosuppression can be safely transitioned to tacrolimus monotherapy as a means of controlling adverse events without an increased risk of mortality or rejection.

Clinical impact using low-dose mycophenolate mofetil with tacrolimus on infectious, noninfectious complications and acute rejection, in renal transplant: A single hospital experience in Mexico

Evidence supporting a starting dose of 2 g/day of mycophenolate mofetil (MMF) in combination with tacrolimus (TAC) for renal transplantation (RT) is still limited, but maintaining a dose of <2 g could result in worse clinical outcomes in terms of acute rejection (AR). This study aimed to determine the association between AR and infectious and noninfectious complications after RT with a dose of 1.5 g vs 2 g of MMF. A prospective cohort study was performed with a 12-month follow-up of recipients of RT from living donors with low (1.5 g/day) or standard (2 g/day) doses of MMF. The association between adverse effects and complications and doses of MMF was examined using Cox proportional hazard models, and survival free of AR, infectious diseases, and noninfectious complications was evaluated using the Kaplan-Meier test. At the end of the follow-up, the incidence of infectious diseases was 52% versus 50% (P = .71) and AR was 5% versus 5% (P = .86), respectively. The survival rate free of gastrointestinal (GI) complications requiring medical attention was higher in the low-dose group than in the standard-dose dose (88% vs 45%, respectively; P < .001). The use of 1.5 g/day of MMF confers a reduction in GI complications without an increase in infectious diseases or the risk of AR.

Case Report: Azathioprine: An Old and Wronged Immunosuppressant

Mycophenolate rapidly substituted azathioprine (AZA) in transplant immunosuppression regimens since the 1990s, when early clinical trials indicated better outcomes, although opposite results were also observed. However, none of these trials used the well-established optimization methods for AZA dosing, namely, thiopurine methyltransferase pharmacogenetics combined with monitoring of the thiopurine metabolites 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP). Resistance to optimize AZA therapy remains today in transplant therapy, despite the fact that thiopurine metabolite testing is being used by other medical disciplines with evident improvement in clinical results. In a previous analysis, we found that active 6-TGN metabolites were not detectable in about 30% of kidney transplant patients under continuous use of apparently adequate azathioprine dosage, which demonstrates the need to monitor these metabolites for therapeutic optimization. Two of four case studies presented here exemplifies this fact. On the other hand, some patients have toxic 6-TGN levels with a theoretically appropriate dose, as seen in the other two case studies in this presentation, constituting one more important reason to monitor the AZA dose administered by its metabolites. This analysis is not intended to prove the superiority of one immunosuppressant over another, but to draw attention to a fact: there are thousands of patients around the world receiving an inadequate dose of azathioprine and, therefore, with inappropriate immunosuppression. This report is also intended to draw attention, to clinicians using thiopurines, that allopurinol co-therapy with AZA is a useful therapeutic pathway for those patients who do not adequately form active thioguanine metabolites.

Immunosuppression in liver and intestinal transplantation

Immunosuppression handling plays a key role in the early and long-term results of transplantation. The development of multiple immunosuppressive drugs led to numerous clincial trials searching to reach the ideal regimen. Due to heterogeneity of the studied patient cohorts and flaws in many, even randomized controlled, study designs, the answer still stands out. Nowadays triple-drug immunosuppression containing a calcineurin inhibitor (preferentially tacrolimus), an antimetabolite (using mycophenolate moffettil or Azathioprine) and short-term steroids with or without induction therapy (using anti-IL2 receptor blocker or anti-lymphocytic serum) is the preferred option in both liver and intestinal transplantation. This chapter aims, based on a critical review of the definitions of rejection, corticoresistant rejection and standard immunosuppression to give some reflections on how to reach an optimal immunosuppressive status and to conduct trials allowing to draw solid conclusions. Endpoints of future trials should not anymore focus on biopsy proven, acute and chronic, rejection but also on graft and patient survival. Correlation between early- and long-term biologic, immunologic and histopathologic findings will be fundamental to reach in much more patients the status of operational tolerance.

Transplant Trial Watch

To keep the transplantation community informed about recently published level 1 evidence in organ transplantation ESOT (https://esot.org/) the Centre for Evidence in Transplantation (www.transplantevidence.com) has developed the Transplant Trial Watch. The Transplant Trial Watch is a monthly overview of 10 new randomized controlled trials (RCTs) and systematic reviews. This page of Transplant International offers commentaries on methodological issues and clinical implications on two articles of particular interest from the CET Transplant Trial Watch monthly selection. For all high-quality evidence in solid organ transplantation, visit the Transplant Library: www.transplantlibrary.com.