Personett, Heather A.

AbstractSolid organ transplant recipients are reliant on immunosuppressive drugs, which have a narrow therapeutic index, and are concurrently vulnerable to adverse drug events due to comorbidity burden and the complexity of their medication regimens. Urgent management of post‐transplant complications often falls to the generalist clinician or critical care specialist. The purpose of this narrative review is to discuss innovations and bedside applications of pharmacogenomics and therapeutic drug monitoring applied to immunosuppression and agents frequently encountered in transplant recipients. Medication formulations will be given specific attention, as interchange is frequently required in the acute care setting. Bioassays quantifying immune system activity will be described with practical applications. A structured approach to addressing drug–drug, drug‐gene, and drug–drug‐gene interactions will be modeled using a case‐based approach synthesizing pharmacogenomics, therapeutic drug monitoring, pharmacokinetics, and pharmacodynamic principles.

PURPOSE:High-dose methotrexate (HDMTX; > 500 mg/m2) is an important component of lymphoma therapy. Serum MTX monitoring at 48 hours is the standard approach to identify those at increased risk of developing MTX toxicity. Our aim was to characterize the incidence of complications and their association with MTX levels.METHODS:A retrospective review of our institutional electronic medical record was conducted to identify patients with lymphoma who received HDMTX between January 1, 2002, and December 31, 2018. We characterized the incidence of acute kidney injury (AKI), intensive care unit (ICU) admission, length of hospital stay (LOS), and 30-day mortality across 48-hour MTX levels. To establish an association between 48-hour MTX levels and the complications listed, we performed chi-square analysis for dichotomous variables and Kruskal-Wallis for nonparametric data. Receiver operator characteristic curve analysis was performed to identify the MTX level where AKI grade ≥ 2 was more likely. Multivariate logistic regression analysis was performed to identify risk factors for this MTX level.RESULTS:We identified 642 patients with 2,804 cycles of HDMTX. The incidence of AKI was 19.1% with AKI grade ≥ 2 making up 21% of cases. Rates of AKI, ICU admission, and 30-day mortality are associated with elevated 48-hour MTX levels. There was a significant increase in median LOS with elevated MTX levels ( P < .001). Receiver operator characteristic curve analysis for AKI grade ≥ 2 demonstrated a 48-hour MTX level threshold of 1.28 μmol/L. Multivariate logistic regression analysis revealed age, male sex, elevated body surface area, higher MTX dose, monotherapy, and first cycle as independent factors.CONCLUSION:Elevated MTX levels are associated with a significant increased rate of AKI, ICU admission, prolonged LOS, and 30-day mortality. Elevated 48-hour MTX levels, particularly > 1.28 μmol/L, should alert clinicians for complications and to initiate measures to reduce MTX levels.

Introduction Acute kidney injury (AKI) affects nearly 20% of all hospitalised patients and is associated with poor outcomes. Long-term complications can be partially attributed to gaps in kidney-focused care and education during transitions. Building capacity across the healthcare spectrum by engaging a broad network of multidisciplinary providers to facilitate optimal follow-up care represents an important mechanism to address this existing care gap. Key participants include nephrologists and primary care providers and in-depth study of each specialty’s approach to post-AKI care is essential to optimise care processes and healthcare delivery for AKI survivors. Methods and analysis This explanatory sequential mixed-methods study uses survey and interview methodology to assess nephrologist and primary care provider recommendations for post-AKI care, including KAMPS (kidney function assessment, awareness and education, medication review, blood pressure monitoring and sick day education) elements of follow-up, the role of multispecialty collaboration, and views on care process-specific and patient-specific factors influencing healthcare delivery. Nephrologists and primary care providers will be surveyed to assess recommendations and clinical decision-making in the context of post-AKI care. Descriptive statistics and the Pearson’s χ 2 or Fisher’s exact test will be used to compare results between groups. This will be followed by semistructured interviews to gather rich, qualitative data that explains and/or connects results from the quantitative survey. Both deductive analysis and inductive analysis will occur to identify and compare themes. Ethics and dissemination This study has been reviewed and deemed exempt by the Institutional Review Board at Mayo Clinic (IRB 20–0 08 793). The study was deemed exempt due to the sole use of survey and interview methodology. Results will be disseminated in presentations and manuscript form through peer-reviewed publication.

Introduction: Contemporary dosing strategies for rabbit anti-thymocyte globulin (rATG) in kidney transplantation aim to reduce cumulative exposure, minimizing long-term adverse events. The use of ideal body weight-based dosing has been trialed, however concern for increased rejection post-transplant exists due to lower doses of rATG. Research Questions: The primary aim of this study was to compare rejection rates between rATG dosing protocols using actual body weight and ideal body weight and secondarily to evaluate cost savings following protocol implementation. Design: This was a retrospective study surrounding implementation of an ideal body weight-based dosing protocol for rATG. We compared 75 kidney transplant recipients in whom rATG was dosed based on actual body weight (pre-protocol group) to 64 in whom dosing was based on ideal body weight (post-protocol group), following a nine-month washout. Results: The mean cumulative rATG dose in the pre-protocol group was 6.3 mg/kg of actual body weight. When ideal body weight was used in the post-protocol group, the mean dose was 4.5 mg/kg of actual body weight. The rejection rate was 18.7% pre-protocol and 23.4% postprotocol, which did not represent a statistically significant difference (p = 0.491). The actual annual cost savings after protocol implementation exceeded $162,000, approximately $2,500 per patient. Conclusion: Results suggest ideal body weight-based dosing of rATG may reduce exposure and cost, without significantly impacting the risk of rejection in kidney transplant recipients. More studies are needed to confirm these findings.

Introduction Orally administered tacrolimus is widely used in hematopoietic cell transplant patients, but multiple clinical situations may arise rendering oral administration infeasible. The undesirable sequelae of intravenous administration, including toxicity, challenges with administration and cost call for innovative solutions to conserve existing supply and optimize safety and efficacy of medication delivery. We sought to demonstrate feasibility of sublingual tacrolimus use and estimate a sublingual-to-oral (SL:PO) conversion ratio in the hematopoietic cell transplant setting. Methods Ten adults undergoing allogeneic hematopoietic cell transplant received tacrolimus 0.04 mg/kg/dose twice daily. Initial doses were given via sublingual route and a steady state trough level was collected after 4 consecutive doses. Participants were then switched to oral tacrolimus, the dose adjusted for a goal trough 8-12ng/mL, and another steady state trough was drawn. Total daily dose was divided by trough concentration for each route to determine the dosing ratio of SL:PO. Results Median trough level following sublingual administration was 11.3 ng/mL. Three of these were within goal, 3 were low (4.7–6.4 ng/mL) and 4 were elevated (15.9–18.6 ng/mL). Median SL:PO ratio was 1.02. In 5 participants the SL:PO ratio was <1 (range 0.57–0.94) and in 5 the ratio was ≥1 (range 1.10–1.92). No significant barriers or intolerance to sublingual tacrolimus use were noted. Conclusions Results demonstrate reliable absorption with sublingual tacrolimus use in patients undergoing hematopoietic cell transplant. Sublingual administration may allow for avoidance of the undesirable complications of IV tacrolimus, such as increased toxicities, required hospitalization for continuous infusion, risk of dose conversion and dilution errors and increased cost. Trial Registry name: Use of Sublingual Tacrolimus in Adult Blood and Marrow Transplant Patients, NCT04041219 https://clinicaltrials.gov/ct2/show/NCT04041219?term=NCT04041219&draw=2&rank=1

Abstract Introduction: Clinical tumor lysis syndrome (TLS), which manifests most often as acute kidney injury (AKI) is a common and devastating complication of rapidly proliferating hematologic malignancies. Epidemiologic studies of attributable risk factors for AKI in this setting are small, focus on only aggressive lymphomas rather than the more prevalent intermediate risk disease subtypes, and predate contemporary risk stratification, diagnostic criteria, and supportive care. Additionally, early administration of rasburicase to enhance uric acid (UA) elimination has been adopted without robust evidence in support of its impact on clinical outcomes, specifically, prevention of AKI. Methods: This was a retrospective cohort study of adult lymphoma patients at intermediate or high risk for TLS treated at Mayo Clinic between 2009 and 2017. Patients were excluded if they had AKI at hospital admission, received pre-admission rasburicase, or were on dialysis. Consensus definitions were used to stratify TLS risk and stage AKI. The incidence of new AKI in the setting of TLS was described along with predictors of its development, including early rasburicase use. Results: Of the 461 patients with a new lymphoma diagnosis during the study timeframe at intermediate or high risk of TLS, 78 were excluded, primarily due to prevalent AKI at hospital admission. The 383 included patients were predominantly at intermediate risk for TLS (73%) and had a diagnosis of Diffuse Large B-cell Lymphoma (64%). Incidence of new onset AKI during hospitalization was 6% and 91% of cases were stage 1. All new onset AKI occurred within the first 5 days of hospital admission. Independent predictors of new AKI included age > 60 years, history of chronic kidney disease or cardiovascular disease, and UA >8 mg/dL at any time during hospital admission. Rasburicase was given to 48 patients, 6 (13%) of whom still went on to develop AKI. Rapid UA reduction with rasburicase did not impact the risk of developing AKI (HR 2.3; p = 0.11). Uric acid level at the time of administration did not modify the effect of rasburicase on prevention of AKI (p = 0.36 for the interaction term). Conclusion: In conclusion, for lymphoma patients at intermediate or high risk for TLS, if not present at admission, AKI only infrequently developed during the course of a patient's hospitalization. Predictors of AKI included advanced age, comorbid conditions, and elevated UA levels. Early rasburicase administration, regardless of UA level, did not alter AKI risk. Disclosures No relevant conflicts of interest to declare.