Factors Influencing Serum Posaconazole Concentrations in Patients with Hematologic Malignancies Receiving Delayed-Release Tablets.

BACKGROUND: Posaconazole (PCZ) plays a crucial role in the prophylaxis and treatment of invasive fungal infections in hematologic malignancies. PCZ concentrations reportedly vary among patients receiving delayed-release tablets (DRT). However, the factors influencing these concentrations remain insufficiently elucidated. Therefore, this study aimed to evaluate the factors influencing PCZ concentrations and their effect on the probability of target attainment (PTA) using a population pharmacokinetic (PPK) approach. We also explored the relationship between PCZ exposure and hepatotoxicity. METHODS: This retrospective study included adult patients with hematologic malignancies who received PCZ DRT. A PPK model was developed based on observational data for 130 concentrations in 28 patients. Simulation analyses were performed to assess the PTA at standard doses of 0.7 and 1.0 mg/L for prophylaxis and treatment, respectively. Estimated concentrations were used to evaluate the correlation between PCZ exposure and hepatotoxicity. RESULTS: Significant factors influencing PCZ concentrations included body weight, serum total protein levels, and diarrhea. Diarrhea correlated with decreased PCZ concentrations resulting in up to 26% lower PTA compared with that without diarrhea. Moreover, PTA declined markedly as the total protein levels decreased from 6.6 g/dL to 4.4 g/dL. The incidence of hepatotoxicity was 17.4% (4/23); no significant relationship could be established between the PCZ concentrations and hepatotoxicity (P = 0.188). CONCLUSIONS: We identified the factors affecting PCZ exposure, which could not be detected by PPK analysis using data from clinical trials. Our results suggest that the generally recommended dose of PCZ causes underexposure in patients with hematologic malignancies characterized by high body weight, hypoproteinemia, or concurrent diarrhea. Therapeutic drug monitoring for DRT may be recommended, especially in patients with these risk factors.

Risk Factors of Cetuximab-Induced Hypomagnesemia and the Effect of Magnesium Prophylaxis in Patients with Head and Neck Cancer: A Retrospective Study.

Hypomagnesemia is a characteristic adverse event of cetuximab in patients with head and neck cancer (HNC). However, there is limited information about its prevalence, risk factors, and preventive strategies. This study aimed to investigate the risk factors of hypomagnesemia and examine the preventive effects of prophylactic magnesium (Mg) administration. We initially investigated HNC patients treated with cetuximab between 2013 and 2019. Our institute started prophylactic Mg treatment (20-mEq Mg sulfate administration before cetuximab) in practice during this period. We retrospectively assess the preventive efficacy by comparing patients before and after its implementation. In total, 109 patients were included. In 60 patients without prophylaxis, all-grade and grade ≥2 hypomagnesemia at 3 months occurred in 61.7 and 15.0% of patients. The incidence of hypomagnesemia was not affected by regimens and concomitant medications. In 49 patients treated with prophylactic Mg treatment, there was no significant decrease in the cumulative incidence of hypomagnesemia. However, the preventive Mg treatment eliminated the need for additional Mg repletion to maintain Mg levels in patients treated with paclitaxel + cetuximab. A risk factor in patients without prophylaxis was a low Mg level at pre-treatment (≤2.0 mg/dL) (odds ratio: 6.03, 95% confidence interval: 1.78-20.4, p = 0.004), whereas that in patients with prophylaxis was the number of cetuximab doses (≥10) (odds ratio: 5.50, 95% confidence interval: 1.52-19.87, p = 0.009). In conclusion, a low pre-treatment Mg level was the only risk factor that could be avoided by prophylactic Mg administration. This preventive intervention is recommended for managing cetuximab-induced hypomagnesemia.

Population pharmacokinetic model and dosing optimization of vancomycin in hematologic malignancies with neutropenia and augmented renal clearance.

AIM: Data on the pharmacokinetics (PK) and area under the curve (AUC)-based dosing strategy of vancomycin (VCM) in hematologic malignancies are limited. According to our preliminary narrative review, only a few population PK analyses in hematologic malignancies have been performed. Therefore, we aimed to develop a population PK model, investigate the factors influencing VCM PK, and propose an optimal dosing regimen for hematologic malignancies. METHODS: A retrospective study was conducted in patients with underlying hematologic malignancies treated with VCM. A total of 148 patients were enrolled for population PK modeling. Simulation analyses were performed to identify dosing regimens achieving a target exposure of AUC0-24 of 400-600 mg h/L at the steady-state. RESULTS: The VCM PK data were best described with a one-compartment model. Significant covariates included creatinine clearance (Ccr), diagnosis of acute myeloid leukemia (AML) and neutropenia on VCM clearance (CL), and body weight (WT) on the volume of distribution (Vd). The typical values of CL and Vd were 3.09 L/h (normalized to Ccr value of 90 mL/min) and 122 L/70 kg, respectively. Concerning the effect on VCM dosing, AML patients required 15% higher doses than non-AML patients, independently of renal function. In contrast, for neutropenic patients, only those with augmented renal clearance (ARC, Ccr value ≥ 130 mL/min) required a 10% dose increase compared to non-neutropenic patients. CONCLUSION: AML patients with neutropenia and ARC represent a critical population with a higher risk of VCM underexposure. Thus, individualized dosing adjustment and therapeutic drug monitoring are strongly recommended.

Systematic surveillance of immune-related adverse events in clinical practice and impact of subsequent steroid medication on survival outcomes.

BACKGROUND: Recent advances in immune-checkpoint inhibitors (ICIs) have highlighted the need for effective management of immune-related adverse events (irAEs). This study aimed to conduct a systematic surveillance of real-world development of irAEs for understanding their characteristics and examine the prognostic impact of steroid use for these events. METHODS: We retrospectively investigated cancer patients treated with ICIs between 2014 and 2021 and collected information about irAEs throughout their development, management, and clinical outcomes. RESULTS: Overall, 458 patients (45.4%) developed 670 irAEs. The prevalence of irAEs varied by cancer type, but it was increased in regimens with longer treatment durations. Severe irAEs were more common in the nivolumab + ipilimumab and pembrolizumab + axitinib regimens. Patients who received steroids for irAEs at a dosage of < 2 mg/kg had comparable prognosis to those who did not receive steroids; however, patients who received methylprednisolone pulse therapy, primarily for severe pneumonitis and hepatitis, had shorter overall survival than those who did not receive steroids (7.8 versus 23.4 months, p = 0.016). Furthermore, methylprednisolone pulse therapy for irAEs was a poor prognostic factor in multivariate analysis (hazard ratio: 2.19, 95% confidence interval: 1.34-2.86, p < 0.001). CONCLUSION: Steroid treatment for irAE does not affect prognosis and should thus be used promptly to control inflammation. However, pulse therapy for severe cases is a poor prognostic factor, and early detection remains the key to managing such irAEs. The irAE characteristics in each regimen should be clarified to establish and provide more sophisticated irAE management, and the current findings will be beneficial to this goal.

Neuroprotective effects of ibudilast against tacrolimus induced neurotoxicity.

Neurotoxicity is one of the major side effects caused by calcineurin inhibitors such as tacrolimus in clinical practice. The underlying mechanisms remain unclear, and no potential protective agents have been identified yet. Here, we aimed to investigate tacrolimus-induced neurotoxicity and assess the protective effects of ibudilast, a nonselective phosphodiesterase inhibitor with neuroprotective effects, against tacrolimus-induced neurotoxicity. An in vitro assay of human neuroblastoma SH-SY5Y cells showed that ibudilast reduced tacrolimus-induced cell death. Subsequently, using in vivo studies, we assessed the pathological mechanism of neurotoxicity and evaluated the protective effect of ibudilast. Wistar rats were subcutaneously administered tacrolimus (2.5 or 5.0 mg/kg/day) for 14 d, and ibudilast (7.5 mg/kg/day) was intraperitoneally administered once a day beginning 2 d prior to tacrolimus (5 mg/kg/day) administration. We observed that ibudilast significantly reduced the tacrolimus-induced neurotoxic events. From the assessment of excised brains, we found that tacrolimus was penetrated to brain and the brain concentration was correlated with the neurotoxicity-score, although ibudilast had no effect on this pharmacokinetics. Tacrolimus-induced neuronal damage was histopathologically evaluated using Nissl and TUNEL staining, where only the cerebral cortex and CA1 region in hippocampus exhibited neuronal death, but not the CA3 region, dendrite gyrus, and cerebellum. Co-administration of ibudilast significantly attenuated these histopathological changes. In conclusion, these results suggest that tacrolimus translocation into the brain and neuronal damage in the cerebral cortex and CA1 are the underlying mechanisms of tacrolimus-induced neurotoxicity and that ibudilast could be a protective agent against this adverse event.

Development and Validation of A Liquid Chromatography-Tandem Mass Spectrometry Method to Simultaneously Measure Tacrolimus and Everolimus Concentrations in Kidney Allograft Biopsies After Kidney Transplantation.

BACKGROUND: Therapeutic drug monitoring is necessary for immunosuppressive therapy with tacrolimus and everolimus after kidney transplantation. Several studies have suggested that the concentrations of immunosuppressive agents in allografts may better reflect clinical outcomes than whole blood concentrations. This study aimed to develop a method for the simultaneous quantification of tacrolimus and everolimus concentrations in clinical biopsy samples and investigate their correlation with histopathological findings in kidney transplant recipients. METHODS: Fourteen biopsy samples were obtained from kidney transplant recipients at 3 months after transplantation. Kidney allograft concentrations (Ctissue) of tacrolimus and everolimus were measured by liquid chromatography-tandem mass spectrometry, and the corresponding whole blood trough concentrations (C0) were obtained from clinical records. RESULTS: The developed method was validated over a concentration range of 0.02-2.0 ng/mL for tacrolimus and 0.04-4.0 ng/mL for everolimus in kidney tissue homogenate. The Ctissue of tacrolimus and everolimus in kidney biopsies ranged from 21.0 to 86.7 pg/mg tissue and 33.5-105.0 pg/mg tissue, respectively. Dose-adjusted Ctissue of tacrolimus and everolimus was significantly correlated with the dose-adjusted C0 (P < 0.0001 and P = 0.0479, respectively). No significant association was observed between the Ctissue of tacrolimus and everolimus and the histopathologic outcomes at 3 months after transplantation. CONCLUSIONS: This method could support further investigation of the clinical relevance of tacrolimus and everolimus allograft concentrations after kidney transplantation.

Development and Validation of an LC-MS/MS Method to Quantify Gilteritinib and Its Clinical Application in Patients With FLT3 Mutation-Positive Acute Myelogenous Leukemia.

BACKGROUND: Gilteritinib, a novel oral tyrosine kinase inhibitor, is used to treat acute myeloid leukemia (AML) with FMS-like tyrosine kinase-3 (FLT3) mutations. Therapeutic drug monitoring (TDM) of gilteritinib is important for improving clinical outcomes and ensuring safety. Therefore, this study aimed to develop a simplified method for quantifying gilteritinib in human plasma using liquid chromatography-tandem mass spectrometry. METHODS: Liquid chromatography was performed by using an Acquity BEH C18 column (50 mm × 2.1 mm, 1.7 µm) and a gradient elution with 0.1% formic acid in water (A) and acetonitrile (B). Detection was performed by using a Shimadzu tandem mass spectrometer through multiple reaction monitoring in the positive-ion mode. RESULTS: The developed method enabled quantification of gilteritinib in 4 minutes and was validated by evaluating selectivity, calibration curve (10-1000 ng/mL, r 2 > 0.99), a lower limit of quantification (LLOQ), accuracy (overall bias -4.2% to 1.9%), precision (intraday CV ≤ 7.9%; interday CV ≤ 13.6%), carryover, recovery, matrix effect, dilution integrity, and stability according to the US Food and Drug Administration (FDA) guidelines. This method was successfully applied to the TDM of gilteritinib trough concentrations in 3 patients with AML. CONCLUSIONS: The developed method fulfilled the FDA guideline criteria and can easily be implemented to facilitate TDM in patients receiving gilteritinib in a clinical setting.

Omeprazole Suppresses Oxaliplatin-Induced Peripheral Neuropathy in a Rodent Model and Clinical Database.

(1) Background: Oxaliplatin is used as first-line chemotherapy not only for colorectal cancer but also for gastric and pancreatic cancers. However, it induces peripheral neuropathy with high frequency as an adverse event, and there is no effective preventive or therapeutic method. (2) Methods: The effects of omeprazole, a proton pump inhibitor (PPI), on oxaliplatin-induced peripheral neuropathy (OIPN) was investigated using an in vivo model and a real-world database. (3) Results: In a rat model, oxaliplatin (4 mg/kg, i.p., twice a week for 4 weeks) caused mechanical hypersensitivity accompanied by sciatic nerve axonal degeneration and myelin sheath disorder. Repeated injection of omeprazole (5−20 mg/kg, i.p., five times per week for 4 weeks) ameliorated these behavioral and pathological abnormalities. Moreover, omeprazole did not affect the tumor growth inhibition of oxaliplatin in tumor bearing mice. Furthermore, clinical database analysis of the Food and Drug Administration Adverse Event Reporting System (FAERS) suggests that the group using omeprazole has a lower reporting rate of peripheral neuropathy of oxaliplatin-treated patients than the group not using (3.06% vs. 6.48%, p < 0.001, reporting odds ratio 0.44, 95% confidence interval 0.32−0.61). (4) Conclusions: These results show the preventing effect of omeprazole on OIPN.

Ibudilast suppresses oxaliplatin-induced mechanical allodynia and neurodegeneration in rats.

Oxaliplatin is a key drug used in the management of solid tumors, such as colorectal cancer; however, it causes peripheral neuropathy. In this study, we investigated the effect of ibudilast, a phosphodiesterase inhibitor, on oxaliplatin-induced mechanical allodynia and histological changes in rats. Ibudilast (7.5 mg/kg, i.p., 5 times per week) reduced mechanical allodynia and histological changes induced by oxaliplatin (4 mg/kg, i.p., twice a week). In contrast, ibudilast (0.01-10 µM) had no effect on oxaliplatin-induced tumor cytotoxicity in murine colon adenocarcinoma 26 cells. These findings suggest that ibudilast could be useful for preventing oxaliplatin-induced peripheral neuropathy in clinical settings.

Risk Factors for Gemcitabine-Induced Vascular Pain in Patients With Pancreatic Cancer.

BACKGROUND: Peripheral intravenous injection of gemcitabine often causes vascular pain; however, preventive measures have not yet been established. OBJECTIVES: This study focused on identifying predictive factors for gemcitabine-induced vascular pain. METHODS: We retrospectively analyzed risk factors for developing vascular pain in patients with pancreatic cancer receiving gemcitabine infusions at our institution. Infusions were divided into groups according to presence or absence of vascular pain symptoms, and variables were compared. Odds ratios for risk factors were calculated using logistic regression analyses. RESULTS: Overall, 272 patients with pancreatic cancer were subjected to 725 gemcitabine infusions, and of these, 18.4% (n = 50) experienced vascular pain. There were significant differences in the gemcitabine dose (P = 0.025), dose of gemcitabine/body surface area (BSA; P = 0.004), concentration of gemcitabine (P = 0.025), and hot pack use (P = 0.011) between the vascular pain and no vascular pain groups. Multivariable analyses indicated that gemcitabine dose/BSA and lack of hot pack use were risk factors for developing vascular pain. Moreover, on administration of a higher dosage (>930 mg/m2), the incidence of vascular pain in patients using a hot pack (6.7%) was significantly lower than that in patients not provided a hot pack (16.2%). CONCLUSIONS AND RELEVANCE: High gemcitabine dosages and lack of hot pack use were predictive factors for gemcitabine-induced vascular pain in patients with pancreatic cancer. Patients receiving gemcitabine treatment should apply a hot pack to the injection site. Scrupulous clinical attention is required for patients presenting with these risk factors to improve pain management.

Analgesic Effects of Sokeikakketsuto on Chemotherapy-Induced Mechanical Allodynia and Cold Hyperalgesia in Rats.

The anticancer agents including oxaliplatin, paclitaxel, and bortezomib cause severe peripheral neuropathy. The Kampo medicine Sokeikakketsuto (SOKT) has been widely used to treat several types of pain. In this study, the analgesic effects of SOKT on oxaliplatin-, paclitaxel-, and bortezomib-induced peripheral neuropathy were investigated in rat models. Rats were treated with oxaliplatin (4 mg/kg, intraperitoneally (i.p.), twice a week for four weeks), paclitaxel (4 mg/kg, i.p., twice a week for two weeks), or bortezomib (0.2 mg/kg, i.p., twice a week for two weeks). SOKT (0.3 or 1.0 g/kg) or duloxetine hydrochloride (30 mg/kg, as a positive control) was administered orally after neuropathy developed. Mechanical allodynia and cold hyperalgesia were assessed using the von Frey test and the acetone test, respectively. These tests were performed immediately before and 30, 60, 90, and 120 min after the administration of the drugs. Repeated treatment of oxaliplatin induced mechanical allodynia and cold hyperalgesia. A single administration of SOKT (1 g/kg, per os (p.o.)), as well as duloxetine, temporarily reversed both the mechanical allodynia and the cold hyperalgesia. Repeated administration of paclitaxel and bortezomib also induced the mechanical allodynia. SOKT and duloxetine reversed the mechanical allodynia caused by bortezomib, but not by paclitaxel. SOKT might have the potential to become a new drug to relieve the symptom of oxaliplatin- or bortezomib-induced peripheral neuropathy.

Development and Full Validation of a Bioanalytical Method for Quantifying Letermovir in Human Plasma Using Ultra-Performance Liquid Chromatography Coupled with Mass Spectrometry.

With the aim of studying the pharmacokinetics of letermovir, which is a newly developed antiviral agent for human cytomegalovirus, a rapid and simple ultra-performance liquid chromatography coupled with mass spectrometry (UPLC/MS) method was developed and validated for the quantification of letermovir in human plasma. Separation was performed in reverse phase mode using an ACQUITY UPLC BEH C18 column (130 Å, 1.7 µm, 2.1 × 50 mm) at a flow rate of 0.3 mL/min, 10 mM ammonium acetate-0.1% formic acid solution as mobile phase A, and acetonitrile as mobile phase B with a gradient elution. The method was validated over a linear range of 10-1000 ng/mL with a coefficient of determination (R2) >0.99 using weighted linear regression analysis. The intra- and inter-assay accuracy (nominal%) and precision (relative standard deviation%) were within ±15 and ≤15%, respectively. The specificity, recovery, matrix effect, stability, and dilution integrity of this method were also within acceptable limits. This method could be useful in studying the pharmacokinetics and pharmacodynamics, as well as performing the therapeutic drug monitoring of letermovir.

Pathological Mechanisms of Bortezomib-Induced Peripheral Neuropathy.

Bortezomib, a first-generation proteasome inhibitor widely used in chemotherapy for hematologic malignancy, has effective anti-cancer activity but often causes severe peripheral neuropathy. Although bortezomib-induced peripheral neuropathy (BIPN) is a dose-limiting toxicity, there are no recommended therapeutics for its prevention or treatment. One of the most critical problems is a lack of knowledge about pathological mechanisms of BIPN. Here, we summarize the known mechanisms of BIPN based on preclinical evidence, including morphological abnormalities, involvement of non-neuronal cells, oxidative stress, and alterations of transcriptional programs in both the peripheral and central nervous systems. Moreover, we describe the necessity of advancing studies that identify the potential efficacy of approved drugs on the basis of pathological mechanisms, as this is a convincing strategy for rapid translation to patients with cancer and BIPN.

Therapeutic Agents for Oxaliplatin-Induced Peripheral Neuropathy; Experimental and Clinical Evidence.

Oxaliplatin is an essential drug in the chemotherapy of colorectal, gastric, and pancreatic cancers, but it frequently causes peripheral neuropathy as a dose-limiting factor. So far, animal models of oxaliplatin-induced peripheral neuropathy have been established. The mechanisms of development of neuropathy induced by oxaliplatin have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory effects on neuropathy. In this review, we summarize the basic and clinical evidence for the therapeutic effects of oxaliplatin. In basic research, there are many reports of neuropathy inhibitors that target oxidative stress, inflammatory response, sodium channel, transient receptor potential (TRP) channel, glutamate nervous system, and monoamine nervous system. Alternatively, very few drugs have clearly demonstrated the efficacy for oxaliplatin-induced peripheral neuropathy in clinical trials. It is important to activate translational research in order to translate basic research into clinical research.

Preclinical and Clinical Evidence of Therapeutic Agents for Paclitaxel-Induced Peripheral Neuropathy.

Paclitaxel is an essential drug in the chemotherapy of ovarian, non-small cell lung, breast, gastric, endometrial, and pancreatic cancers. However, it frequently causes peripheral neuropathy as a dose-limiting factor. Animal models of paclitaxel-induced peripheral neuropathy (PIPN) have been established. The mechanisms of PIPN development have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory PIPN effects. This review summarizes the basic and clinical evidence for therapeutic or prophylactic effects for PIPN. In pre-clinical research, many reports exist of neuropathy inhibitors that target oxidative stress, inflammatory response, ion channels, transient receptor potential (TRP) channels, cannabinoid receptors, and the monoamine nervous system. Alternatively, very few drugs have demonstrated PIPN efficacy in clinical trials. Thus, enhancing translational research to translate pre-clinical research into clinical research is important.

Usefulness of daily folic acid supplementation during methotrexate treatment of Japanese patients with rheumatoid arthritis.

OBJECTIVES: We investigated the effect of daily folic acid supplementation on methotrexate (MTX) toxicity and efficacy in Japanese patients with rheumatoid arthritis (RA). METHODS: We followed 19 patients treated with MTX who switched from taking weekly 5 mg folic acid supplementation (weekly regimen) to 1.25 mg daily (daily regimen). White blood cell (WBC) and platelet (PLT) counts, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels were collected for 24 weeks following the change. RESULTS: We observed no significant changes in WBC or PLT counts. AST and ALT levels, which had exceeded the upper limits of their normal ranges at the beginning of the study, were improved significantly at weeks 4 and 8, no subsequent deterioration in liver function was found. Further, no significant changes in ESR and CRP levels were observed. CONCLUSION: Our data indicate that supplementing 1.25 mg of folic acid daily rather than 5 mg weekly reduces toxicity caused by MTX without affecting its efficacy.

Effects of Diluent Volume and Administration Time on the Incidence of Anaphylaxis Following Docetaxel Therapy in Breast Cancer.

Hypersensitivity reactions, including anaphylaxis, are common side effects associated with docetaxel treatment in breast cancer patients. However, preventive measures have not yet been established. In this study, we retrospectively analyzed the risk factors for developing anaphylaxis in 182 female breast cancer patients treated with docetaxel. We found that 6.6% of all patients (n = 12) experienced anaphylaxis. Multivariate analyses indicated that concentration of docetaxel higher than 0.275 mg/m2/mL, docetaxel dose rate higher than 1.15 mg/m2/min, and white blood cell count less than 4290 cells/mL are risk factors for developing docetaxel-related anaphylaxis. In particular, concentrations of docetaxel or doses per administration time were associated with a high odds ratio (11.88 or 11.60) for docetaxel-related anaphylaxis. Moreover, patients receiving doses in 250 mL volume experienced anaphylaxis more frequently than those receiving doses in 500 mL (7.0 vs. 0.9%, p = 0.0236). Additionally, patients receiving treatments over 60 min tended to experience anaphylaxis more frequently than those who were treated over 90 min (6.7 vs. 1.1%, p = 0.0637). The present results indicate that high docetaxel concentrations, high dose rates, and low white blood cell counts are risk factors for developing docetaxel-related anaphylaxis, and administering docetaxel diluted in 500 mL over 90 min may limit docetaxel-induced hypersensitivity reactions.

Increasing Diluent Volume Decreases Bendamustine-Induced Venous Irritation without Reducing the Therapeutic Efficacy.

The intravenous injection of bendamustine often induces venous irritation, which reduces patients' QOL. We previously reported that the dilution of the final volume of bendamustine from 250 to 500 mL significantly decreased the incidence of venous irritation. However, the influence of this change on the therapeutic efficacy of bendamustine remains unclear. Therefore, the aim of this study was to evaluate the efficacy and safety profiles of bendamustine at different dilutions of the final volume, comparing with the correspondences of previous studies. Thirty-four patients, who received a total of 161 courses of bendamustine and rituximab chemotherapy, were included in this study. The overall response rate of this regimen was 94.1% in this study, which was comparable to that reported in the BRB study (94.2%, a phase II study of bendamustine plus rituximab therapy in Japanese patients). Additionally, the median progression-free survival was not inferior to that reported in the BRB study. Bendamustine-induced venous irritation was observed in 17.6% of the patients during the first treatment cycle administered at a final volume of 500 mL, and was found to be lower than that observed in the control, where bendamustine was administered at a final volume of 250 mL (85.7%). These results suggest that diluting bendamustine to 500 mL, but not to 250 mL, reduces the incidence of venous irritation without a negative impact on its therapeutic efficacy; thus, this simple strategy may be beneficial to ensure efficacy and safety in patients receiving regimens including bendamustine.

Donor CYP3A5 Gene Polymorphism Alone Cannot Predict Tacrolimus Intrarenal Concentration in Renal Transplant Recipients.

CYP3A5 gene polymorphism in recipients plays an important role in tacrolimus blood pharmacokinetics after renal transplantation. Even though CYP3A5 protein is expressed in renal tubular cells, little is known about the influence on the tacrolimus intrarenal exposure and hence graft outcome. The aim of our study was to investigate how the tacrolimus intrarenal concentration (Ctissue) could be predicted based on donor CYP3A5 gene polymorphism in renal transplant recipients. A total of 52 Japanese renal transplant patients receiving tacrolimus were enrolled in this study. Seventy-four renal biopsy specimens were obtained at 3 months and 1 year after transplantation to determine the donor CYP3A5 polymorphism and measure the Ctissue by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The tacrolimus Ctissue ranged from 52 to 399 pg/mg tissue (n = 74) and was weak but significantly correlated with tacrolimus trough concentration (C0) at 3 months after transplantation (Spearman, r = 0.3560, p = 0.0096). No significant relationship was observed between the donor CYP3A5 gene polymorphism and Ctissue or Ctissue/C0. These data showed that the tacrolimus systemic level has an impact on tacrolimus renal accumulation after renal transplantation. However, donor CYP3A5 gene polymorphism alone cannot be used to predict tacrolimus intrarenal exposure. This study may be valuable for exploring tacrolimus renal metabolism and toxicology mechanism in renal transplant recipients.

Influence of POR*28 Polymorphisms on CYP3A5*3-Associated Variations in Tacrolimus Blood Levels at an Early Stage after Liver Transplantation.

It is well known that the CYP3A5*3 polymorphism is an important marker that correlates with the tacrolimus dose requirement after organ transplantation. Recently, it has been revealed that the POR*28 polymorphism affects the pharmacokinetics of tacrolimus in renal transplant patients. In this study, we examined whether POR*28 as well as CYP3A5*3 polymorphism in Japanese recipients and donors would be another biomarker for the variation of tacrolimus blood levels in the recipients during the first month after living-donor liver transplantation. We enrolled 65 patients treated with tacrolimus, who underwent liver transplantation between July 2016 and January 2019. Genomic DNA was extracted from whole-blood samples, and genotyping was performed to examine the presence of CYP3A5*3 and POR*28 polymorphisms in the recipients and donors. The CYP3A5*3/*3 genotype (defective CYP3A5) of the recipient (standard partial regression coefficient [median C/D ratio of CYP3A5 expressor vs. CYP3A5 non-expressor, p value]: Pod 1-7, ß= -0.389 [1.76 vs. 2.73, p < 0.001]; Pod 8-14, ß = -0.345 [2.03 vs. 2.83, p < 0.001]; Pod 15-21, ß= -0.417 [1.75 vs. 2.94, p < 0.001]; Pod 22-28, ß = -0.627 [1.55 vs. 2.90, p < 0.001]) rather than donor (Pod 1-7, ß = n/a [1.88 vs. 2.76]; Pod 8-14, ß = n/a [1.99 vs. 2.93]; Pod 15-21, ß = -0.175 [1.91 vs. 2.94, p = 0.004]; Pod 22-28, ß = n/a [1.61 vs. 2.67]) significantly contributed to the increase in the concentration/dose (C/D) ratio of tacrolimus for at least one month after surgery. We found that the tacrolimus C/D ratio significantly decreased from the third week after transplantation when the recipient carried both CYP3A5*1 (functional CYP3A5) and POR*28 (n = 19 [29.2%], median C/D ratio [inter quartile range] = 1.58 [1.39-2.17]), compared with that in the recipients carrying CYP3A5*1 and POR*1/*1 (n = 8 [12.3%], median C/D ratio [inter quartile range] = 2.23 [2.05-3.06]) (p < 0.001). In conclusion, to our knowledge, this is the first report suggesting that the POR*28 polymorphism is another biomarker for the tacrolimus oral dosage after liver transplantation in patients carrying CYP3A5*1 rather than CYP3A5*3/*3.