Intra-individual variability of mycophenolic acid concentration according to renal function in liver transplant recipients receiving mycophenolate monotherapy

Immune Monitoring of Mycophenolate Mofetil Activity in Healthy Volunteers Using Ex Vivo T Cell Function Assays

Mycophenolate mofetil (MMF) is part of the standard immunosuppressive treatment after transplantation and usually given as "one-dose-fits-all" together with a calcineurin inhibitor (CNI). Although drug concentrations are frequently monitored, there is still a group of patients who experience side effects related to excessive or insufficient immune suppression. We therefore aimed to identify biomarkers that reflect the overall immune status of the patient and might support individualized dosing. We previously studied immune biomarkers for CNIs and aimed to investigate whether these are also suitable to monitor MMF activity. Healthy volunteers received a single dose of MMF or placebo, after which IMPDH enzymatic activity, T cell proliferation, and cytokine production were measured and compared to MPA (MMF's active metabolite) concentration in three different matrices (plasma, peripheral blood mononuclear cells, and T cells). MPA concentrations in T cells exceeded those in PBMCs, but all intracellular concentrations correlated strongly with plasma concentrations. At clinically relevant MPA concentrations, IL-2 and IFN-γ production was mildly suppressed, while MPA T cell proliferation was strongly inhibited. Based on these data, it is expected that monitoring of T cell proliferation in MMF-treated transplantation patients may be a valid strategy to avoid excessive immune suppression.

Therapeutic drug monitoring of immunosuppressive drugs in hepatology and gastroenterology

Immunosuppressive drugs have been key to the success of liver transplantation and are essential components of the treatment of inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH). For many but not all immunosuppressants, therapeutic drug monitoring (TDM) is recommended to guide therapy. In this article, the rationale and evidence for TDM of tacrolimus, mycophenolic acid, the mammalian target of rapamycin inhibitors, and azathioprine in liver transplantation, IBD, and AIH is reviewed. New developments, including algorithm-based/computer-assisted immunosuppressant dosing, measurement of immunosuppressants in alternative matrices for whole blood, and pharmacodynamic monitoring of these agents is discussed. It is expected that these novel techniques will be incorporate into the standard TDM in the next few years.

Prognostic value of endogenous and exogenous metabolites in liver transplantation

Liver transplantation has been widely accepted as an effective intervention for end-stage liver diseases and early hepatocellular carcinomas. However, a variety of postoperative complications and adverse reactions have baffled medical staff and patients. Currently, transplantation monitoring relies primarily on nonspecific biochemical tests, whereas diagnosis of multiple complications depends on invasive pathological examination. Therefore, a noninvasive monitoring method with high selectivity and specificity is desperately needed. This review summarized the potential of endogenous small-molecule metabolites as biomarkers for assessing graft function, ischemia-reperfusion injury and liver rejection. Exogenous metabolites, mainly those immunosuppressive agents with high intra- and inter-individual variability, were also discussed for transplantation monitoring.

Pretransplant Hepatic Malignancy Increases Risk of De Novo Malignancy after Liver Transplantation

BACKGROUND

Hepatocellular carcinoma (HCC) recurrence and development of de novo malignancy (DNM) after liver transplantation (LT) are the major causes of late recipient death.

METHODS

We analyzed the incidence of extrahepatic DNM following living donor LT according to the status of pretransplant hepatic malignancy. We selected 2,076 adult patients who underwent primary LDLT during 7 years from January 2010 to December 2016.

RESULTS

The pretransplant hepatic malignancy group (n = 1,012) showed 45 cases (4.4%) of the following extrahepatic DNMs: posttransplant lymphoproliferative disease (PTLD) in 10; lung cancer in 10; stomach cancer in 6; colorectal cancer in 5; urinary bladder cancer in 3; and other cancers in 11. The pretransplant no hepatic malignancy group (n = 1,064) showed 25 cases (2.3%) of the following extrahepatic DNMs: colorectal cancer in 3; stomach cancer in 3; leukemia in 3; lung cancer in 3; PTLD in 2; prostate cancer in 2; and other cancers in 9. Incidences of extrahepatic DNM in the pretransplant hepatic malignancy and no hepatic malignancy groups were as follows: 1.1% and 0.5% at 1 year, 3.2% and 2.0% at 3 years, 4.6% and 2.5% at 5 years, and 5.4% and 2.8% at 8 years, respectively (P = 0.006). Their overall patient survival rates were as follows: 97.3% and 97.2% at 1 year, 91.6% and 95.9% at 3 years, 89.8% and 95.4% at 5 years, and 89.2% and 95.4% at 8 years, respectively (P < 0.001). Pretransplant hepatic malignancy was the only significant risk factor for posttransplant extrahepatic DNM.

CONCLUSION

Our results suggest that patients who had pretransplant hepatic malignancy be followed up more strictly because they have a potential risk of primary hepatic malignancy recurrence as well as a higher risk of extrahepatic DNM than patients without pretransplant hepatic malignancy.

Treatment and outcomes of extrahepatic malignancy incidentally diagnosed during pretransplant evaluation for living donor liver transplantation

BACKGROUND

This study analyzed treatment and outcomes in patients with primary extrahepatic malignancy (EHM) incidentally diagnosed during pretransplant evaluation for living donor liver transplantation (LDLT).

METHODS

Of 4621 adult patients undergoing LDLT over 19 years, 41 were diagnosed with EHM shortly before LDLT (incidental malignancy group), and 92 had been treated for EHM more than 6 months before LDLT (treated malignancy group).

RESULTS

Most common EHMs were colorectal, thyroid, and stomach cancers in the incidental malignancy group; and stomach, breast, thyroid, colorectal, and renal cell cancers and lymphoma in the treated malignancy group. Mean interval between EHM diagnosis and LDLT in the incidental malignancy group was 1.5 ± 1.6 months. Of the 41 patients in this group, 15 (35.6%), seven (17.1%), and 16 (39.0%) underwent EHM treatment before, during, and after LDLT, respectively, whereas three (7.3%) underwent observation alone. During a mean follow-up of 70.1 ± 50.8 months, six (14.6%) patients showed tumor recurrence, and three (7.3%) died of tumor progression. All recurrences developed in patients with tumor stages higher than the earliest stage. The mean interval between EHM diagnosis and LDLT in treated malignancy group was 79.8 ± 79.6 months. During a mean follow-up of 63.2 ± 54.1 months, three (3.3%) patients showed tumor recurrence and one (1.1%) died of tumor progression. The incidence of EHM recurrence was significantly higher (P = .025), and the overall post-transplant patient survival rate was significantly lower (P = .046), in the incidental malignancy than in the treated malignancy group.

CONCLUSIONS

Only patients with earliest-stage EHM detected shortly before LDLT are indicated for upfront LDLT combined with peritransplant EHM treatment.

Cross-sectional analysis of immunosuppressive regimens focused on everolimus after liver transplantation in a Korean high-volume transplantation center

Background

The mammalian target of the rapamycin inhibitor has dual inhibitory effects on cell growth and angiogenesis. This study aimed to analyze the usage of everolimus on actual immunosuppression (IS) regimens through a cross-sectional study in a high-volume liver transplantation (LT) center.

Methods

Our institutional LT database was searched for adult patients who underwent primary LT surgery between January 2010 and December 2016. We identified 2,093 LT recipients with observation periods of 1 to 8 years.

Results

We divided the 2,093 recipients into three groups according to the posttransplant follow-up period as follows: group A (12–36 months; n=680), group B (37–60 months; n=560), and group C (>60 months; n=853). The individual IS agents were tacrolimus in 1,807 patients (86.3%), cyclosporine in 169 patients (8.1%), mycophenolate mofetil (MMF) in 1,310 patients (62.6%), and everolimus in 115 patients (5.5%). The most common IS regimens were tacrolimus-MMF combination and tacrolimus monotherapy, regardless of the posttransplant period. Patients with pretransplant malignancies were administered everolimus more frequently than those without pretransplant malignancies (P<0.001). In 102 patients with hepatocellular carcinoma recurrence or de novo malignancies, IS regimens included everolimus-tacrolimus in 41 patients (40.2%), tacrolimus-MMF in 27 patients (26.4%), tacrolimus in 20 patients (19.6%), MMF in 10 patients (9.8%), cyclosporine in three patients (2.9%), and cyclosporine-MMF in one patient (1.0%).

Conclusions

Administration of everolimus after LT has been gradually increasing with the expansion of indications in our institutional practice. Currently, the role of everolimus is minimal and not comparable to that of tacrolimus, but it has a unique position in the field of IS after LT.

A cross-sectional analysis of long-term immunosuppressive regimens after liver transplantation at Asan Medical Center: Increased preference for mycophenolate mofetil

Backgrounds/Aims

Long-term immunosuppression regimens after liver transplantation (LT) are rarely reported in detail. We aimed to provide information on actual long-term immunosuppression regimens through this cross-sectional study.

Methods

Our institutional LT database was searched for adult patients who underwent primary LT operation from 2000 to 2016. We identified 3620 live recipients with actual information on immunosuppressive agent use for 1-17 years.

Results

The study cohort was divided into 7 groups according to posttransplantation period. The immunosuppressive agents used at the cross-sectional review period were tacrolimus in 2884 (79.7%), cyclosporine in 445 (12.3%), mycophenolate mofetil in 2007 (55.4%), and everolimus in 138 (3.8%) recipients. There was no marked difference in immunosuppressive agent use according to pretransplantation liver malignancy or type of LT operation. Tacrolimus, cyclosporine, mycophenolate mofetil, and everolimus were used in 97.4%, 1.8%, 60.9%, and 9.2%, respectively, in the year 2 group; 94.1%, 3.9%, 51.6%, and 8.3%, respectively, in the year 3 group; 87.3%, 8.4%, 68.9%, and 4.8%, respectively, in the year 4-5 group; 78.2%, 12.9%, 64.6%, and 3.0%, respectively, in the year 6-7 group; 76.9%, 10.8%, 58.8%, and 2.4%, respectively, in the year 8-10 group; 66.7%, 22.4%, 43.4%, and 1.5%, respectively, in the year 11-15 group; and 73.8%, 15.4%, 32.9%, and 1.7%, respectively, in the year ≥15 group.

Conclusions

Tacrolimus and mycophenolate mofetil are the primary immunosuppressive agents after LT, and the indications for everolimus have started to increase at our institution. We believe our results will help establish tailored long-term immunosuppression regimens.