Clinical validation of two volumetric absorptive microsampling devices to support home-based therapeutic drug monitoring of immunosuppression.

AIMS: Dried blood volumetric absorptive microsamples (VAMS) may facilitate home-based sampling to enhance therapeutic drug monitoring after transplantation. This study aimed to clinically validate a liquid chromatography-tandem mass spectrometry assay using 2 VAMS devices with different sampling locations (Tasso-M20 for the upper arm and Mitra for the finger). Patient preferences were also evaluated. METHODS: Clinical validation was performed for tacrolimus and mycophenolic acid by comparison of paired VAMS and venipuncture samples using Passing-Bablok regression and Bland-Altman analysis. Conversion of mycophenolic acid VAMS to serum concentrations was evaluated using haematocrit-dependent formulas and fixed correction factors defined a priori. Patients' perspectives, including useability, acceptability and feasibility, were also investigated using established questionnaires. RESULTS: Paired samples (n = 50) were collected from 25 kidney transplant recipients. Differences for tacrolimus whole-blood concentration were within ±20% for 86 and 88% of samples from the upper arm and fingerstick, respectively. Using correction factors of 1.3 for the upper-arm and 1.47 for finger-prick samples, 84 and 76% of the paired samples, respectively, were within ±20% for mycophenolic acid serum concentration. Patient experience surveys demonstrated limited pain and acceptable useability of the upper-arm device. CONCLUSIONS: Tacrolimus and mycophenolic acid can be measured using 2 common VAMS devices with similar analytical performance. Patients are supportive of home-based monitoring with a preference for the Tasso-M20 device.

Sweet and simple as syrup: A review and guidance for use of novel antihyperglycemic agents for post-transplant diabetes mellitus and type 2 diabetes mellitus after kidney transplantation.

Uncontrolled type 2 diabetes mellitus (T2DM) and post-transplant diabetes mellitus (PTDM) increase morbidity and mortality after kidney transplantation. Conventional strategies for diabetes management in this population include metformin, sulfonylureas, meglitinides and insulin. Limitations with these agents, as well as promising new antihyperglycemic agents, create a need and opportunity to explore additional options for transplant diabetes pharmacotherapy. Novel agents including sodium glucose co-transporter 2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP1RA), and dipeptidyl peptidase IV inhibitors (DPP4i) demonstrate great promise for T2DM management in the non-transplant population. Moreover, many of these agents possess renoprotective, cardiovascular, and/or weight loss benefits in addition to improved glucose control while having reduced risk of hypoglycemia compared with certain other conventional agents. This comprehensive review examines available literature evaluating the use of novel antihyperglycemic agents in kidney transplant recipients (KTR) with T2DM or PTDM. Formal grading of recommendations assessment, development, and evaluation (GRADE) system recommendations are provided to guide incorporation of these agents into post-transplant care. Available literature was evaluated to address the clinical questions of which agents provide greatest short- and long-term benefits, timing of novel antihyperglycemic therapy initiation after transplant, monitoring parameters for these antihyperglycemic agents, and concomitant antihyperglycemic agent and immunosuppression regimen management. Current experience with novel antihyperglycemic agents is primarily limited to single-center retrospective studies and case series. With ongoing use and increasing comfort, further and more robust research promises greater understanding of the role of these agents and place in therapy for kidney transplant recipients.

Predictive Capacity of Population Pharmacokinetic Models for the Tacrolimus Dose Requirements of Pediatric Solid Organ Transplant Recipients.

BACKGROUND: Transplant recipients require individualized tacrolimus doses to maximize graft survival. Multiple pediatric tacrolimus population pharmacokinetic (PopPK) models incorporating CYP3A5 genotype and other covariates have been developed. Identifying the optimal popPK model is necessary for clinical implementation in pediatric solid organ transplant. The primary objective was to compare the dose prediction capabilities of the developed models in pediatric kidney and heart transplant recipients. METHODS: Pediatric kidney or heart transplant recipients treated with tacrolimus and available CYP3A5 genotype data were identified. The initial weight-based tacrolimus dose and first therapeutic tacrolimus dose were collected retrospectively. Three published popPK models were used to predict the tacrolimus dose required to achieve a tacrolimus trough concentration of 10 ng/mL. Model dose predictions were compared with the initial and first therapeutic doses using Friedman test. The first therapeutic dose was plotted against the model-predicted dose. RESULTS: The median initial dose approximately 2-fold lower than the first therapeutic dose for CYP3A5 expressers. The Chen et al model provided the closest estimates to the first therapeutic dose for kidney transplant recipients; however, all 3 models tended to underpredict the observed therapeutic dose. For heart transplant recipients, Andrews et al model predicted doses that were higher than the initial dose but similar to the actual therapeutic dose. CONCLUSIONS: Weight-based tacrolimus dosing appears to underestimate the tacrolimus dose requirements. The development of a separate popPK model is necessary for heart transplant recipients. A genotype-guided strategy based on the Chen et al model provided the best estimates for doses in kidney transplant recipients and should be prospectively evaluated.

The use of non-transplant biologics in solid organ transplant recipients: A practical review for the frontline clinician.

Biologics have become the forefront of medicine for management of autoimmune conditions, leading to improved quality of life. Many autoimmune conditions occur in solid organ transplant (SOT) recipients and persist following transplant. However, the use of biologics in this patient population is not well studied, and questions arise related to risk of infection and adjustments to induction and maintenance immunosuppression. Guidelines have been published highlighting management strategies of biologics around the time of elective surgical procedures, but this is not always feasible in urgent situations, especially with deceased donor transplantation. The aim of this review is to summarize the current literature regarding the use of these agents in solid organ transplant recipients, and specifically address induction and maintenance immunosuppression, as well as the need for alternative infective prevention strategies to create a practical reference for the frontline clinician, when faced with this complex clinical scenario.

A multicenter evaluation of hepatitis B reactivation with and without antiviral prophylaxis after kidney transplantation.

BACKGROUND: Hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg)-negative and hepatitis B core antibody (anti-HBc)-positive kidney transplant recipients ranges between 1.4% and 9.6%. Limited evidence is available regarding routine antiviral prophylaxis and identifiable risk factors for HBV reactivation in this population. METHODS: In this multicenter retrospective study, we evaluated the prevalence of HBV reactivation in HBsAg-negative anti-HBc-positive kidney transplant recipients who did or did not receive antiviral prophylaxis. The primary outcome assessed the prevalence of HBV reactivation, defined as a positive HBV DNA by PCR of any viral load at or above the minimal detection level. The principal safety outcomes assessed 1-year graft survival, 1-year all-cause mortality, biopsy-proven acute rejection, and antibody-mediated rejection. RESULTS: One hundred and sixty-one patients met inclusion criteria and comprised two groups, antiviral prophylaxis (n = 14) and no antiviral prophylaxis (n = 147). Of patients who did not receive prophylaxis, only five (3.4%) experienced HBV reactivation, whereas one (7.1%) patient in the prophylaxis group experienced reactivation over a median follow-up of 1103 days (p = .43). Furthermore, there were no differences with respect to all secondary outcomes. Statistical analysis demonstrated delayed graft function to be a significant factor associated with HBV reactivation. CONCLUSION: These study results suggest that the prevalence of HBV reactivation in HBsAg-negative anti-HBc-positive kidney transplant recipients is low, regardless of antiviral prophylaxis. Furthermore, there were no significant graft-related outcomes among those that did experience reactivation.

A call for transplant stewardship: The need for expanded evidence-based evaluation of induction and biologic-based cost-saving strategies in kidney transplantation and beyond.

Rising expenditures threaten healthcare sustainability. While transplant programs are typically considered profitable, transplant medications are expensive and frequently targeted for cost savings. This review aims to summarize available literature supporting cost-containment strategies used in solid organ transplant. Despite widespread use of these tactics, we found the available evidence to be fairly low quality. Strategies mainly focus on induction, particularly rabbit antithymocyte globulin (rATG), given its significant cost and the lack of consensus surrounding dosing. While there is higher-quality evidence for high single-dose rATG, and dose-rounding protocols to reduce waste are likely low risk, more aggressive strategies, such as dosing rATG by CD3+ target-attainment or on ideal-body-weight, have less robust support and did not always attain similar efficacy outcomes. Extrapolation of induction dosing strategies to rejection treatment is not supported by any currently available literature. Cost-saving strategies for supportive therapies, such as IVIG and rituximab also have minimal literature support. Deferral of high-cost agents to the outpatient arena is associated with minimal risk and increases reimbursement, although may increase complexity and cost-burden for patients and infusion centers. The available evidence highlights the need for evaluation of unique patient-specific clinical scenarios and optimization of therapies, rather than simple blanket application of cost-saving initiatives in the transplant population.

Comparison of standard versus low-dose valganciclovir regimens for cytomegalovirus prophylaxis in high-risk liver transplant recipients.

PURPOSE: The purpose of this study was to compare the safety and efficacy of two valganciclovir (VGCV) institutional dosing protocols for cytomegalovirus (CMV) prophylaxis in liver transplant (LT) recipients with CMV serotype donor +/recipient- (D+/R-). METHODS: This was a single-center review of CMV D+/R- adult LT recipients who received VGCV 450 mg/day for 90 days (low-dose) or VGCV 900 mg/day for 180 days (standard-dose). The primary outcome was incidence of CMV disease at 1 year. Secondary outcomes included rates of CMV syndrome, end-organ disease, breakthrough infection, and resistance. Neutropenia, early discontinuation of VGCV, growth colony stimulating factors use (G-CSF), biopsy-proven rejection (BPAR), graft loss, and death at 1 year were analyzed. RESULTS: Ninety-six CMV D+/R- LT recipients were included. Although no difference in CMV disease was observed (low-dose 26% vs. standard-dose 23%, p = 0.71), 75% of CMV infections in the low-dose group presented with end-organ disease. Ganciclovir (GCV) resistance was observed only in the low-dose group (n = 2). Significantly more patients in the standard-dose group developed neutropenia (low-dose 10% vs 60% standard-dose, p < 0.001). In the standard-dose group, 29% required early discontinuation of VGCV (vs. 5% in the low-dose group, p < 0.001), and 20% were treated with G-CSF. Both cohorts had similar rates of BPAR, graft loss, and death at 1 year. CONCLUSIONS: VGCV 900 mg/day for 180 days had higher rates of hematologic adverse effects resulting in frequent treatment interruptions. However, the occurrence of two cases of GCV-resistant CMV disease raises concerns about routinely using low-dose VGCV prophylaxis.

Increasing net immunosuppression after BK polyoma virus infection.

BACKGROUND: Reducing immunosuppression can effectively treat BK viremia (BKV) and BK nephropathy, but has been associated with increased risks for acute rejection and development of donor-specific antibodies (DSA). To date there have been no systematic evaluations of re-escalating immunosuppression in transplant patients with resolving BKV. Importantly, the safety of this approach and impact on graft survival is unclear. METHODS: We performed a single-center retrospective review of kidney transplant recipients between July 2011 and June 2013 who had immunosuppression reduction after developing BKV (plasma PCR ≥ 1000 copies/ml). Changes in immunosuppression and patient outcomes were tracked until occurrence of a complication event: biopsy-proven acute rejection (BPAR), detection of de novo DSA, or recurrent BKV. Patients were grouped according to whether or not net immunosuppression was eventually increased. RESULTS: Out of 88 patients with BKV, 44 (50%) had net immunosuppression increased while the other 44 did not. Duration of viremia, peak viremia, induction, and sensitization status were similar between the two groups. In a Kaplan-Meier analysis, increasing immunosuppression was associated with less BPAR (P = .001) and a trend toward less de novo DSA development (P = .06). Death-censored graft survival (P = .27) was not different between the two groups. In the net immunosuppression increase group, recurrent BKV occurred in 22.7% without any BKV-related graft losses. CONCLUSION: These findings support potential benefits of increasing immunosuppression in patients with low-level or resolved BKV, but prospective trials are needed to better understand such an approach.

Oropharyngeal candidiasis outcomes in renal transplant recipients receiving nystatin versus no antifungal prophylaxis.

OBJECTIVE: To compare the incidence of oropharyngeal candidiasis (OC), or thrush, in renal transplant recipients receiving nystatin versus no antifungal prophylaxis. METHODS: This was a single-center, retrospective, non-inferiority study of adult renal transplant recipients (RTRs) who received nystatin for 30 days for OC prophylaxis (nystatin group) or no antifungal prophylaxis therapy (No PPX group). The primary outcome was the incidence of OC within 3 months post-transplant. Secondary outcomes included time to OC occurrence and severity of OC. The pre-specified non-inferiority margin was 10%. RESULTS: The incidence of OC within 3 months post-transplant among 257 RTRs was 7.8% (10/128) in the No PPX group and 4.7% (6/129) RTRs in the nystatin group, a risk difference of 3.2% (95% CI, -2.7% to 9.1%, non-inferiority P = .04). The median time to OC was 7.5 days (IQR 6.3-34.3 days) in the nystatin group and 9.5 days (IQR 5.3-30.5 days) in the No PPX group (P = .64). Esophageal candidiasis was observed in 10% (1/10) of RTRs with OC in the No PPX group compared to 16.7% (1/6) RTRs in the nystatin group (P = 1.00). All RTRs with OC achieved symptom resolution with fluconazole and/or nystatin. Two patients in the No PPX group required readmission for decreased oral intake, and OC was diagnosed and treated during their hospital day. CONCLUSIONS: In this retrospective study of adult RTRs, the absence of antifungal prophylaxis demonstrated non-inferiority to 30-day nystatin prophylaxis at reducing the incidence of OC within 3 months of transplant. OC prophylaxis may not be warranted after renal transplant.

Utilization of direct-acting oral anticoagulation in solid organ transplant patients: A national survey of institutional practices.

The safety and efficacy of direct-acting oral anticoagulants (DOACs) and reversal strategies are not well established in the solid organ transplant population. This was a survey of pharmacists to assess DOAC and urgent reversal practices among adult transplant programs in the United States. A 27-question survey was distributed to members of transplant pharmacy organization listservs between 5/28/19 and 6/30/19. A total of 115 responses were received from kidney (43.5%), heart (20.0%), lung (18.3%), liver (13.9%), and pancreas (4.4%) transplant programs. DOAC use prior to transplant was mostly prohibited in thoracic programs (77.3%) but more permissive in kidney transplant programs (64.0%). If permitted, apixaban (57.8%) was most preferred. At transplant surgery, reversal of DOAC was performed "as needed" (20.9%) or was not routine (18.3%). DOAC use post-transplant was more permissive (94.3%). A majority of responders follow FDA recommended dosing in the setting of drug-drug interactions (51.1%). Major factors influencing DOAC prescribing decisions included renal function, drug-drug interactions, and insurance. High clinical practice variability exists regarding DOAC utilization and urgent reversal strategies in pre-, peri-, and post-transplant stages. While more research is needed to refine the clinical landscape, many institutions are using DOAC therapy under the perception that they pose a similar risk of bleeding compared to a non-transplant population.

Alternatives to immediate release tacrolimus in solid organ transplant recipients: When the gold standard is in short supply.

Given the current climate of drug shortages in the United States, this review summarizes available comparative literature on the use of alternative immunosuppressive agents in adult solid organ transplant recipients including kidney, pancreas, liver, lung, and heart, when immediate-release tacrolimus (IR-TAC) is not available. Alternative options explored include extended-release tacrolimus (ER-TAC) formulations, cyclosporine, belatacept, mammalian target of rapamycin inhibitors, and novel uses of induction therapy for maintenance immunosuppression. Of available alternatives, only ER-TAC formulations are of non-inferior efficacy compared to IR-TAC when used de novo or after conversion in stable kidney transplant recipients (KTRs). All other alternatives were associated with higher rates of biopsy-proven rejection, but improved tolerance from classic adverse effects of IR-TAC including nephrotoxicity and development of diabetes. While most alternative therapies are approved in KTRs, access via third-party payors is an obstacle in non-KTRs. In the setting of IR-TAC shortage, alternate therapeutic options may be plausible depending on the organ population and individual patient situation to ensure appropriate, effective immunosuppression for each patient.

Safety and efficacy of direct-acting oral anticoagulants versus warfarin in kidney transplant recipients: a retrospective single-center cohort study.

Despite the increased use, comparative safety and efficacy of direct-acting oral anticoagulants (DOACs) against warfarin have not been well studied in kidney transplant recipients. In this single-center retrospective study, we evaluated 197 adult kidney transplant recipients on DOAC or warfarin between January 1, 2011, and June 30, 2018. The primary outcome was incidence of major bleeding defined as a hemoglobin decrease ≥2 g/dl, blood transfusion ≥2 units, or symptomatic bleeding in a critical area or organ. Patients were initiated on anticoagulation therapy at a median of 6.5 years post-transplant and followed for a median of 12.3 months. The rates of major bleeding were 7.2% per year with DOACs vs. 11.4% per year with warfarin (Mantel-Cox P = 0.15). No difference was found in composite bleeding, clinically relevant nonmajor bleeding, or thromboembolic events between the groups. There was a lower incidence of major bleeding with apixaban compared to all other anticoagulants (6.7% vs. 19.0%, P = 0.027). After controlling for potential confounders, DOAC use was not associated with an increased risk of major bleeding (HR 0.73, 95% CI 0.27-1.95). Further research is warranted to definitively determine whether DOACs are effective and safe alternatives to warfarin for anticoagulation in kidney transplant recipients.

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.

A national survey of valganciclovir dosing strategies in pediatric organ transplant recipients.

PURPOSE: Data remain limited on the most appropriate valganciclovir (VGCV) dosing strategy for cytomegalovirus (CMV) prophylaxis and treatment in pediatric organ transplant recipients. Therefore, the objective of this study was to describe methods used to calculate VGCV dosing among pediatric transplant centers. METHODS: A survey of pharmacists was conducted to assess VGCV dosing strategies for CMV prophylaxis and treatment among pediatric organ transplant centers in the U.S. FINDINGS: Of 54 centers that perform pediatric organ transplants, 22 (40.7%) centers responded to the survey. Fourteen centers (53.8%) utilize the Food and Drug Administration (FDA) recommended VGCV dosing strategy of 7 × body surface area (BSA) × creatinine clearance (CrCl) for CMV prophylaxis. Other dosing strategies reported included weight based and 520 mg/m2  × BSA per day. Dosing strategies of VGCV for the treatment of CMV also differed across centers, with a majority (43.5%) using 7 × BSA × CrCl twice daily. CONCLUSION: Less than two-thirds of centers utilize the FDA-approved daily dosing regimen with various methods of CrCl calculation and serum creatinine assay measurements used. More retrospective and prospective studies with clinical outcomes associated with VCGV dosing strategies are warranted to determine the most appropriate prophylaxis and treatment strategies for CMV.

Population pharmacokinetics of mycophenolic acid and its glucuronide metabolite in lung transplant recipients with and without cystic fibrosis.

1. Cystic fibrosis (CF) is a disease affecting multiple organs that may reduce the systemic exposure of some drugs. The objective of this work was to characterize and compare the population pharmacokinetics (PK) of the immunosuppressant mycophenolic acid (MPA), and its glucuronide metabolite (MPAG) in adult lung transplant recipients with and without CF (NCF) following repeated oral administration of the prodrug mycophenolate mofetil (MMF). 2. A population PK model was developed, with simultaneous modeling of MPA and MPAG, using nonlinear mixed effects modeling. MPA and MPAG serum concentration-time data were adequately described by a compartmental model including enterohepatic recirculation (EHR). Both MPA and MPAG apparent clearance values were significantly elevated (>65%) in patients with CF (24.1 and 1.95 L/h, respectively) compared to the values in the NCF patients (14.5 and 1.12 L/h, respectively), suggesting a notable influence of CF on MPA absorption and disposition. 3. The population PK model developed from our study successfully characterized the absorption, distribution, elimination and EHR of MPA and the metabolite MPAG in lung transplant recipients with or without CF. This model may help to further understand the impact of CF to the overall clinical effects of MPA therapy including immunosuppression and gastrointestinal side effects.

Multicenter evaluation of efficacy and safety of low-dose versus high-dose valganciclovir for prevention of cytomegalovirus disease in donor and recipient positive (D+/R+) renal transplant recipients.

BACKGROUND: The cytomegalovirus (CMV) donor-positive/recipient-positive (D+/R+) population is the largest proportion of renal transplant recipients (RTR). Guidelines for prevention of CMV in the intermediate-risk D+/R+ population include prophylaxis with valganciclovir (VGCV) 900 mg/day for 3 months. This study is the first head-to-head analysis, to our knowledge, comparing the efficacy and safety CMV prophylaxis of VGCV 450 vs 900 mg/day for 3 months in D+/R+ RTR. METHODS: A multicenter, retrospective analysis evaluated 478 adult RTR between January 2008 and October 2011. Study participants received VGCV 450 mg/day (Group 1; n=398) or 900 mg/day (Group 2; n=89)×3 months for CMV prophylaxis. All VGCV was adjusted for renal function. All groups included in this study received study-approved induction and maintenance immunosuppression regimens. The primary endpoint was incidence of CMV disease at 12 months. RESULTS: The rates of graft loss, patient survival, T-cell and/or antibody-mediated rejection, hematological adverse events, opportunistic infections, and early VGCV discontinuation were evaluated. Patient demographics were comparable, but had significant differences in ethnicity and donor type between the groups. CONCLUSION: The occurrence of CMV disease at 12 months was similar between the groups (3.5% vs 3.4%; P=1.000). Log-rank test found no statistically significant difference in the time to development of CMV between the 2 groups (P=.939).

Immunosuppression in Solid-Organ Transplantation: Essentials and Practical Tips.

A multidisciplinary team approach is essential for successful management of patients with solid-organ transplant. Transplant nursing encompasses care and support of transplant recipients as well as caregivers and organ donors through all phases of transplantation, from pretransplant evaluation to posttransplant recovery and maintenance. The field of solid-organ transplantation has advanced rapidly, and new treatments continue to emerge. Nurses who are responsible for the care of transplant recipients should have a knowledge base in transplant immunology and pharmacology. This review discusses mechanism of action, indication, side effects, and drug interactions of commonly used immunosuppressive medications in solid-organ transplantation. Nonoral routes of drug administration, therapeutic drug monitoring, and patient monitoring strategies are also included as practical tips for bedside nurses who are responsible for delivery of direct patient care and education of patients and their caregivers. This review focuses on the following medications: antithymocyte globulins, basiliximab, alemtuzumab, corticosteroids, tacrolimus, cyclosporine, azathioprine, mycophenolate mofetil/mycophenolate sodium, sirolimus, everolimus, belatacept, intravenous immunoglobulin, and rituximab.

Population pharmacokinetics of mycophenolic acid in lung transplant recipients with and without cystic fibrosis.

PURPOSE: The objective of this work was to characterize and compare the population pharmacokinetics (PK) mycophenolic acid (MPA) in adult lung transplant recipients with cystic fibrosis (CF) and without the disease (NCF) following repeated oral administration of the prodrug mycophenolate mofetil (MMF) as an immunosuppressant. METHODS: Three separate 12-h PK visits were conducted for lung transplant patients with or without CF following repeated MPA treatment with at least a 2-week break between the visits. A population PK model was developed using nonlinear mixed effects modeling (NONMEM), and the contribution of physiological and pathological factors and time dependence of apparent oral clearance (CL/F) were assessed. RESULTS: For both CF and NCF patients, MPA serum concentration-time profiles were best described by a two-compartment PK model with first-order absorption. CF patients had a slower absorption rate (Ka), and elevated CL/F and volume of distribution (Vd/F) compared with NCF patients. There is a significant contribution of body weight and CF disease to MPA CL/F, and both were included in the final model as covariates. CONCLUSIONS: The population PK model developed from our study successfully characterizes the absorption, distribution, and elimination of MPA in lung transplant recipients with or without CF disease. The decrease of MPA absorption and increase of both oral clearance (CL/F) and volume of distribution (V2/F and V3/F) in the CF patients would suggest the importance of MPA therapeutic monitoring for this group.

Mycophenolic acid pharmacokinetics in lung transplant recipients with cystic fibrosis.

BACKGROUND: Lung transplantation is an established treatment for cystic fibrosis (CF) patients with end-stage lung disease. Current immunosuppression includes the prodrug mycophenolate mofetil (MMF), which has led to improved transplant outcomes. Given the pancreatic insufficiency and malabsorption in CF patients, some transplant centers give higher doses of MMF to these patients based on lower predose levels (C(0)), even though C(0) values correlate poorly with mycophenolic acid (MPA) exposure. The focus of this pilot study was to determine the pharmacokinetics (PK) of MPA in CF when compared with noncystic fibrosis (NCF) lung transplant recipients. METHODS: Five CF and 5 NCF patients had 3 separate PK analyses performed through our clinical research center. In addition to MMF, all patients were on tacrolimus and prednisone and were diabetic on insulin. Twelve-hour total serum concentration-time profiles of MPA and MPA glucuronide (MPAG) were obtained after oral administration of MMF. Concentrations of total MPA and MPAG were determined by a validated liquid chromatography-tandem mass spectrometry method. PK parameters of MPA were calculated by the noncompartmental method. Student t test or Mann-Whitney test was used to assess the differences in the PK parameters between the 2 cohorts. RESULTS: CF patients were significantly younger (30.6 versus 59.4 years; P < 0.001) and had significantly lower serum albumin (3.8 versus 4.1 g/dL; P = 0.0018) than NCF patients. CF patients had significantly lower MPA area under the curve (47.7 versus 83.1 mg·h·L(-1); P = 0.016) and MPAG area under the curve (569 versus 911 mg·h·L(-1); P = 0.047) when compared with NCF patients. In addition, C(0) (2.6 versus 4.6 mg/L; P = 0.026) and maximum serum concentration (9.2 versus 20.3 mg/L; P = 0.016) were significantly lower, and apparent oral clearance (0.26 versus 0.13 L·h·kg(-1); P = 0.009) was significantly higher in CF patients. T(max) was delayed in CF patients but not significantly. No difference between CF and NCF patients was observed for intra- and interindividual variability. CONCLUSIONS: Given these results, the lower MPA exposure in CF patients may impact transplant outcome in this lung transplant population.

The efficacy and safety of sodium-glucose cotransporter-2 inhibitors in solid organ transplant recipients: A scoping review.

Sodium glucose co-transporter 2 (SGLT2) inhibitors are used for the treatment of diabetes and for their cardiovascular and kidney benefits in patients with or without diabetes. Use in solid organ transplant recipients is controversial because transplant recipients were excluded from the major clinical trials assessing SGLT2 inhibitors. The goal of this review was to assess the available literature regarding the use of SGLT2 inhibitors in solid organ transplant recipients. A PubMed search was conducted for studies published in English through December 31, 2023. Studies were excluded if they were meta-analyses, review articles, commentaries, single case reports, or in vitro studies, or did not involve the use of SGLT2 inhibitors in solid organ transplant recipients with a diabetic, cardiovascular, or kidney outcome being assessed. In the final review, 20 studies were included: kidney (n = 15), heart (n = 4), and liver/lung/kidney (n = 1) transplant recipients. SGLT2 inhibitors had similar A1c reduction efficacy and were found to be weight neutral with possible weight reduction effects. Cardiovascular and kidney outcomes were not adequately assessed in the available studies. Adverse effects were reported to occur at a similar rate in transplant recipients compared to the general population. SGLT2 inhibitors were initiated ≥1-year post-transplant in most transplant recipients included in these studies. The overall safety and antihyperglycemic efficacy of SGLT2 inhibitors in kidney and heart transplant recipients is similar to the general population. Data assessing SGLT2 inhibitors use in solid organ transplant recipients for longer durations are needed.