Methadone pharmacokinetics in opioid agonist treatment: Influencing factors and clinical implications

BACKGROUND

A considerable inter-individual variability has been reported in the relationship between methadone doses applied and serum concentrations achieved in methadone maintenance treatment. However, the underlying causes for this variability are not fully understood.

OBJECTIVES

We investigated the influence of genetic, pathophysiological and pharmacological factors on serum methadone concentration-to-dose ratio (CDR) and discussed the clinical implications of the findings.

METHODS

We used data from two retrospective laboratory databases and a prospective cohort study to investigate the impact on methadone CDR of hepatic cytochrome P450 enzyme system (CYP) genetic polymorphisms, age, sex, concomitant medication, liver fibrosis and body mass index through linear mixed model analyses.

FINDINGS

A positive association was found between CDR and the homozygous CYP2B6*6 genotype, concurrent treatment with CYP3A4 inhibitors and body mass index. CDR was lower among women and during concomitant use of CYP inducers. CDR was not associated with age or the degree of liver fibrosis in our investigations.

CONCLUSIONS

This research work supports the need for individually tailored dosage considering the various factors that influence methadone CDR. The gained knowledge can contribute to reducing the risks associated with the treatment and optimizing the desired outcomes.

Lack of pharmacokinetic interaction between derazantinib and naringin in rats

CONTEXT

Derazantinib-an orally bioavailable, ATP competitive, multikinase inhibitor-has strong activity against fibroblast growth factor receptors (FGFR)2, FGFR1, and FGFR3 kinases. It has preliminary antitumor activity in patients with unresectable or metastatic FGFR2 fusion-positive intrahepatic cholangiocarcinoma (iCCA).

OBJECTIVE

This experiment validates a novel sensitive and rapid method for the determination of derazantinib concentration in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), and applies it to the study of drug-drug interaction between derazantinib and naringin in vivo.

MATERIALS AND METHODS

A Xevo TQ-S triple quadrupole tandem mass spectrometer was used for mass spectrometry monitoring in selective reaction monitoring (SRM) mode with transitions of m/z 468 96 → 382.00 for derazantinib and m/z 488.01 → 400.98 for pemigatinib, respectively. The pharmacokinetics of derazantinib (30 mg/kg) was investigated in Sprague-Dawley (SD) rats divided into two groups (with the oral pretreatment of 50 mg/kg naringin or not).

RESULTS

The newly optimized UPLC-MS/MS method was suitable for the determination of derazantinib in rat plasma. It was also successfully employed to evaluate the effect of naringin on derazantinib metabolism in rats. After pretreatment with naringin, there was no significant difference in the pharmacokinetic parameters (AUC_0→t, AUC_0→∞, t_1/2, CLz/F, and C_max) of derazantinib when compared with derazantinib alone.

CONCLUSION

Co-administration of naringin with derazantinib was not associated with significant changes in pharmacokinetic parameters. Thus, this study suggests that the combination of derazantinib with naringin can safely be administered concomitantly without dose adjustment.

Impact of Disease States on the Oral Pharmacokinetics of EIDD-1931 (an Active Form of Molnupiravir) in Rats for Implication in the Dose Adjustment

The pharmacokinetic alteration of an antimicrobial medication leading to sub-therapeutic plasma level can aid in the emergence of resistance, a global threat nowadays. In this context, molnupiravir (prodrug of EIDD-1931) is the most efficacious orally against corona virus disease (COVID-19). In addition to drug-drug interaction, the pharmacokinetics of a drug can significantly vary during any disease state, leading to disease-drug interaction. However, no information is available for such a recently approved drug. Therefore, we aimed to explore the oral pharmacokinetics of EIDD-1931 in seven chemically induced disease states individually compared to the normal state using various rat models. Induction of any disease situation was confirmed by the disease specific study(s) prior to pharmacokinetic investigations. Compared to the normal state, substantially lowered plasma exposure (0.47- and 0.63-fold) with notably enhanced clearance (2.00- and 1.56-fold) of EIDD-1931 was observed in rats of ethanol-induced gastric injury and carbon tetrachloride-induced liver injury states. Conversely, paclitaxel-induced neuropathic pain and cisplatin-induced kidney injury states exhibited opposite outcomes on oral exposure (1.43- and 1.50-fold) and clearance (0.69- and 0.65-fold) of EIDD-1931. Although the highest plasma concentration (2.26-fold) markedly augmented in the doxorubicin-induced cardiac injury state, streptozocin-induced diabetes and lipopolysaccharide-induced lung injury state did not substantially influence the pharmacokinetics of EIDD-1931. Exploring the possible phenomenon behind the reduced or boosted plasma exposure of EIDD-1931, results suggest the need for dose adjustment in respective diseased conditions in order to achieve desired efficacy during oral therapy of EIDD-1931.

The impact of gene polymorphism and hepatic insufficiency on voriconazole dose adjustment in invasive fungal infection individuals

Voriconazole (VRZ) is a broad-spectrum antifungal medication widely used to treat invasive fungal infections (IFI). The administration dosage and blood concentration of VRZ are influenced by various factors, posing challenges for standardization and individualization of dose adjustments. On the one hand, VRZ is primarily metabolized by the liver, predominantly mediated by the cytochrome P450 (CYP) 2C19 enzyme. The genetic polymorphism of CYP2C19 significantly impacts the blood concentration of VRZ, particularly the trough concentration (Ctrough), thereby influencing the drug's efficacy and potentially causing adverse drug reactions (ADRs). Recent research has demonstrated that pharmacogenomics-based VRZ dose adjustments offer more accurate and individualized treatment strategies for individuals with hepatic insufficiency, with the possibility to enhance therapeutic outcomes and reduce ADRs. On the other hand, the security, pharmacokinetics, and dosing of VRZ in individuals with hepatic insufficiency remain unclear, making it challenging to attain optimal Ctrough in individuals with both hepatic insufficiency and IFI, resulting in suboptimal drug efficacy and severe ADRs. Therefore, when using VRZ to treat IFI, drug dosage adjustment based on individuals' genotypes and hepatic function is necessary. This review summarizes the research progress on the impact of genetic polymorphisms and hepatic insufficiency on VRZ dosage in IFI individuals, compares current international guidelines, elucidates the current application status of VRZ in individuals with hepatic insufficiency, and discusses the influence of CYP2C19, CYP3A4, CYP2C9, and ABCB1 genetic polymorphisms on VRZ dose adjustments and Ctrough at the pharmacogenomic level. Additionally, a comprehensive summary and analysis of existing studies' recommendations on VRZ dose adjustments based on CYP2C19 genetic polymorphisms and hepatic insufficiency are provided, offering a more comprehensive reference for dose selection and adjustments of VRZ in this patient population.

Obesity in adult acute myeloid leukemia is not associated with inferior response or survival even when dose capping anthracyclines: An ECOG-ACRIN analysis

BACKGROUND

Obesity (body mass index [BMI] ≥30 kg/m2 ) is an important epidemiological risk factor for developing acute myeloid leukemia (AML). Therefore, the authors studied the association of obesity with clinical and genetic phenotype and its impact on outcome in adults with AML.

METHODS

The authors analyzed BMI in 1088 adults who were receiving intensive remission induction and consolidation therapy in two prospective, randomized therapeutic clinical trials of the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network: E1900 (ClinicalTrials.gov identifier NCT00049517; patients younger than 60 years) and E3999 (ClinicalTrials.gov identifier NCT00046930; patients aged 60 years or older).

RESULTS

Obesity was prevalent at diagnosis (33%) and, compared with nonobesity, was associated with intermediate-risk cytogenetics group (p = .008), poorer performance status (p = .01), and a trend toward older age (p = .06). Obesity was not associated with somatic mutations among a selected 18-gene panel that was tested in a subset of younger patients. Obesity was not associated with clinical outcome (including complete remission, early death, or overall survival), and the authors did not identify any patient subgroup that had inferior outcomes based on BMI. Obese patients were significantly more likely to receive <90% of the intended daunorubicin dose despite protocol specification, particularly in the E1900 high-dose (90 mg/m2 ) daunorubicin arm (p = .002); however, this did not correlate with inferior overall survival on multivariate analysis (hazard ratio, 1.39; 95% confidence interval, 0.90-2.13; p = .14).

CONCLUSIONS

Obesity is associated with unique clinical and disease-related phenotypic features in AML and may influence physician treatment decisions regarding daunorubicin dosing. However, the current study demonstrates that obesity is not a factor in survival, and strict adherence to body surface area-based dosing is not necessary because dose adjustments do not affect outcomes.

Identification of Medication Prescription Errors and Factors of Clinical Relevance in 314 Hospitalized Patients for Improved Multidimensional Clinical Decision Support Algorithms

Potential medication errors and related adverse drug events (ADE) pose major challenges in clinical medicine. Clinical decision support systems (CDSSs) help identify preventable prescription errors leading to ADEs but are typically characterized by high sensitivity and low specificity, resulting in poor acceptance and alert-overriding. With this cross-sectional study we aimed to analyze CDSS performance, and to identify factors that may increase CDSS specificity. Clinical pharmacology services evaluated current pharmacotherapy of 314 patients during hospitalization across three units of two Swiss tertiary care hospitals. We used two CDSSs (pharmaVISTA and MediQ), primarily for the evaluation of drug-drug interactions (DDI). Additionally, we evaluated potential drug-disease, drug-age, drug-food, and drug-gene interactions. Recommendations for change of therapy were forwarded without delay to treating physicians. Among 314 patients, automated analyses by both CDSSs produced an average of 15.5 alerts per patient. In contrast, additional expert evaluation resulted in only 0.8 recommendations per patient to change pharmacotherapy. For clinical pharmacology experts, co-factors such as comorbidities and laboratory results were decisive for the classification of CDSS alerts as clinically relevant in individual patients in about 70% of all decisions. Such co-factors should therefore be used for the development of multidimensional CDSS alert algorithms with improved specificity. In combination with local expert services, this poses a promising approach to improve drug safety in clinical practice.

Pharmacokinetics of Venetoclax Co-Administered with Posaconazole in Patients with Acute Myeloid Leukemia

The Food and Drug Administration currently approves the combination of hypomethylating agents (HMA), azacytidine or decitabine with venetoclax (VEN) for acute myeloid leukemia (AML) patients aged more than 75 years and for patients unsuitable for intensive chemotherapy. The risk of fungal infection in the early phase of treatment is not negligible; therefore, posaconazole (PCZ) is commonly administered as primary prophylaxis. A drug-drug interaction between VEN and PCZ is well known, but the trend of serum levels of venetoclax when both drugs are overlapped is not clear. In total, 165 plasma samples from 11 elderly AML patients receiving combined treatment with HMA, VEN and PCZ were analyzed by a validated analytical method (high-pressure liquid chromatography-tandem mass spectrometry). Venetoclax trough plasma concentrations were detected during the 3 days of ramp-up as well as on day 7 and day 12 of treatment when the exposure as the area under the plasma concentration-time curve and the accumulation ratio were also calculated. The results were compared with the expected data for 400 mg/dose VEN administered alone-the confirmed high inter-individual variability in pharmacokinetics suggests the need for therapeutic drug monitoring.

Clinical Treatment Guidelines for Tafasitamab Plus Lenalidomide in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) accounts for approximately 24% of new cases of B-cell non-Hodgkin lymphoma in the US each year. Up to 50% of patients relapse or are refractory (R/R) to the standard first-line treatment option, R-CHOP. The anti-CD19 monoclonal antibody tafasitamab, in combination with lenalidomide (LEN), is an NCCN preferred regimen for transplant-ineligible patients with R/R DLBCL and received accelerated approval in the US (July 2020) and conditional marketing authorization in Europe (August 2021) and other countries, based on data from the L-MIND study. The recommended dose of tafasitamab is 12 mg/kg by intravenous infusion, administered in combination with LEN 25 mg for 12 cycles, followed by tafasitamab monotherapy until disease progression or unacceptable toxicity. Tafasitamab + LEN is associated with durable responses in patients with R/R DLBCL. The majority of clinically significant treatment-associated adverse events are attributable to LEN and can be managed with dose modification and supportive therapy. We provide guidelines for the management of patients with R/R DLBCL treated with tafasitamab and LEN in routine clinical practice, including elderly patients and those with renal and hepatic impairment, and advice regarding patient education as part of a comprehensive patient engagement plan. Our recommendations include LEN administration at a reduced dose if required in patients unable to tolerate the recommended dose. No dose modification is required for tafasitamab in special patient populations.

Vancomycin audit in the paediatric population: Patterns of use and appropriateness of therapeutic drug monitoring

AIMS

This study aims to investigate prescribing and therapeutic drug monitoring (TDM) practices for vancomycin in paediatrics at the Jordan University Hospital and to determine the impact of inaccuracies in TDM data on dosing decisions.

METHODS

Patterns of vancomycin prescriptions, appropriateness of vancomycin dosing, duration, TDM, and the accuracy of the recorded dosing/sampling times were determined prospectively based on prespecified criteria. Finally, Monte Carlo simulations were undertaken using the mrgsolve-package in R to assess the effect of inaccuracies in recording dosing/sampling times on subsequent dose adjustments.

RESULTS

Four hundred forty-two vancomycin courses were analysed. Vancomycin prescriptions were mainly empirical (77.4%). Initial vancomycin doses were appropriate in 73.1% of vancomycin courses. Prolonged use (>5 days) was found in 45.7% of admissions with negative cultures; this was related to the diagnosis of suspected sepsis unadjusted-OR: 1.8 (1.1-2.9). TDM was appropriately ordered in 90.7% of concentrations. Discrepancies between the recorded and actual times were noted in 83.9% and 82.7% of audited times of dose administration and sample collection, respectively. Based on simulations, these discrepancies were predicted to result in inappropriate dose adjustment in 37.9% of patients.

CONCLUSIONS

Inappropriate empirical and prolonged vancomycin use and inaccuracies in recording dosing/sampling times are important areas of improvement in the current clinical practice.

Chemotherapy and Anticancer Drugs Adjustment in Obesity: A Narrative Review

BACKGROUND

Obese individuals have higher rates of cancer incidence and cancer- related mortality. The worse chemotherapy outcomes observed in this subset of patients are multifactorial, including the altered physiology in obesity and its impact on pharmacokinetics, the possible increased risk of underdosing, and treatment-related toxicity.

AIMS

The present review aimed to discuss recent data on physiology, providing just an overall perspective and pharmacokinetic alterations in obesity concerning chemotherapy. We also reviewed the controversies of dosing adjustment strategies in adult and pediatric patients, mainly addressing the use of actual total body weight and ideal body weight.

METHODS

This narrative review tried to provide the best evidence to support antineoplastic drug dosing strategies in children, adolescents, and adults.

RESULTS

Cardiovascular, hepatic, and renal alterations of obesity can affect the distribution, metabolism, and clearance of drugs. Anticancer drugs have a narrow therapeutic range, and variations in dosing may result in either toxicity or underdosing. Obese patients are underrepresented in clinical trials that focus on determining recommendations for chemotherapy dosing and administration in clinical practice. After considering associated comorbidities, the guidelines recommend that chemotherapy should be dosed according to body surface area (BSA) calculated with actual total body weight, not an estimate or ideal weight, especially when the intention of therapy is the cure.

CONCLUSION

The actual total body weight dosing appears to be a better approach to dosing anticancer drugs in both adults and children when aiming for curative results, showing no difference in toxicity and no limitation in treatment outcomes compared to adjusted doses.

Pharmacogenetic Dose Modeling Based on CYP2C19 Allelic Phenotypes

Pharmacogenetic variability in drug metabolism leads to patient vulnerability to side effects and to therapeutic failure. Our purpose was to introduce a systematic statistical methodology to estimate quantitative dose adjustments based on pharmacokinetic differences in pharmacogenetic subgroups, addressing the concerns of sparse data, incomplete information on phenotypic groups, and heterogeneity of study design. Data on psychotropic drugs metabolized by the cytochrome P450 enzyme CYP2C19 were used as a case study. CYP2C19 activity scores were estimated, while statistically assessing the influence of methodological differences between studies, and used to estimate dose adjustments in genotypic groups. Modeling effects of activity scores in each substance as a population led to prudential predictions of adjustments when few data were available ('shrinkage'). The best results were obtained with the regularized horseshoe, an innovative Bayesian approach to estimate coefficients viewed as a sample from two populations. This approach was compared to modeling the population of substance as normally distributed, to a more traditional "fixed effects" approach, and to dose adjustments based on weighted means, as in current practice. Modeling strategies were able to assess the influence of study parameters and deliver adjustment levels when necessary, extrapolated to all phenotype groups, as well as their level of uncertainty. In addition, the horseshoe reacted sensitively to small study sizes, and provided conservative estimates of required adjustments.

Durable effect of pyrotinib plus capecitabine in HER-2+ breast cancer patient undergoing peritoneal dialysis: A case report and literature review

For patients with end-stage renal disease (ESRD), peritoneal dialysis (PD) and hemodialysis (HD) are important renal replacement treatments. Patients on dialysis usually have a high incidence rate of malignant tumors. In 2020, breast cancer has become the malignant tumor with the highest incidence rate in the world. Human epidermal growth factor receptor-2-positive (HER-2+) breast cancer accounts for 20%-30% of the total breast cancer patients. It is highly invasive and has a poor prognosis. Anti-HER-2 treatment is an important therapy for this type of cancer. There are few case reports of anti-HER2-targeted therapy in dialysis patients. We report a 56-year-old Chinese woman with breast cancer (cT3N1MX, Her-2+/HR-). She underwent peritoneal dialysis for 11 years since she had suffered end-stage renal disease. The clinician prescribed the regimen (pyrotinib 320mg qd + capecitabine 1g bid D1-D14 Q3W). The tumor was significantly reduced after 1 month of single administration of pyrotinib, and partially relieved after 2 months of pyrotinib + capecitabine. The main side effects were grade II hand foot syndrome and grade II diarrhea. This case shows that the combination of pyrotinib and capecitabine has potential therapeutic benefits in HER-2+ breast cancer patients with end-stage renal disease.

Vancomycin therapeutic drug monitoring in patients on continuous renal replacement therapy: a retrospective study

Objectives

This study aimed to investigate vancomycin therapeutic drug monitoring (TDM) in patients on continuous renal replacement therapy (CRRT) and explore the risk factors for exceeding the target concentration.

Methods

This retrospective study enrolled patients aged ≥18 years who were admitted to the intensive care unit and treated with ≥3 intravenous vancomycin doses during CRRT, and who underwent vancomycin TDM. Demographic and other information were collected. Multivariate logistic regression was used assess the risk factors for exceeding the target concentration.

Results

Sixty-nine patients were included, and 40.6% patients underwent TDM. Additionally, 14.5% of patients reached the optimal concentration, and 87.5% of patients who exceeded the target received a daily dose adjustment. The cumulative dose of vancomycin and serum albumin were risk factors for exceeding the target concentration in patients on CRRT.

Conclusions

Patients on CRRT did not meet the optimal vancomycin management; <50% of the patients routinely received vancomycin TDM, and <15% achieved the optimal concentration. Fewer patients in the subtherapeutic group received a daily dose adjustment than those who exceeded the target concentration. Cumulative vancomycin and serum albumin doses before TDM were the risk factors for exceeding the target concentration in CRRT patients.

Development of Physiology Based Pharmacokinetic Model to Predict the Drug Interactions of Voriconazole and Venetoclax

PURPOSE

Venetoclax (VEN), an anti-tumor drug that is a substrate of cytochrome P450 3A enzyme (CYP3A4), is used to treat leukemia. Voriconazole (VCZ) is an antifungal medication that inhibits CYP3A4. The goal of this study is to predict the effect of VCZ on VEN exposure.

METHOD

Two physiological based pharmacokinetics (PBPK) models were developed for VCZ and VEN using the bottom-up and top-down method. VCZ model was also developed to describe the effect of CYP2C19 polymorphism on its pharmacokinetics (PK). The reversible inhibition constant (Ki) of VCZ for CYP3A4 was calibrated using drug-drug interaction (DDI) data of midazolam and VCZ. The clinical verified VCZ and VEN model were used to predict the DDI of VCZ and VEN at clinical dosing scenario.

RESULT

VCZ model predicted VCZ exposure in the subjects of different CYP2C19 genotype and DDI related fold changes of sensitive CYP3A substrate with acceptable prediction error. VEN model can capture PK of VEN with acceptable prediction error. The DDI PBPK model predicted that VCZ increased the exposure of VEN by 4.5-9.6 fold. The increase in VEN exposure by VCZ was influenced by subject's CYP2C19 genotype. According to the therapeutic window, VEN dose should be reduced to 100 mg when co-administered with VCZ.

CONCLUSION

The PBPK model developed here could support individual dose adjustment of VEN and DDI risk assessment. Predictions using the robust PBPK model confirmed that the 100 mg dose adjustment is still applicable in the presence of VCZ with high inter-individual viability.

Risk of polymyxin B-induced acute kidney injury with a non adjusted dose versus adjusted dose based on renal function

Aim: To observe the difference in the risk of polymyxin B (PMB)-induced acute kidney injury (AKI) with or without dose adjustment based on the patients renal function. Materials & methods: This retrospective cohort analysis was carried out in 115 patients treated with PMB from November 2018 to October 2019. Results: No significant difference in the incidence of AKI as well as secondary outcomes was observed between these two groups (47.5 vs 37.14%; p = 0.304). Conclusion: Dosing adjustment based on renal function does not significantly lower the risk of PMB-induced AKI. A non adjusted dosing strategy for PMB is recommended in patients exhibiting various levels of renal impairment.

Cefepime Induced Neurotoxicity Following A Regimen Dose-Adjusted for Renal Function: Case Report and Review of the Literature

Introduction: Cefepime induced neurotoxicity (CIN) is commonly associated with renal dysfunction, however CIN can occur in patients with normal renal function or renally dose-adjusted regimens. Few reports of this kind have obtained cefepime concentrations to assist in diagnosis. Patient Case: A 42-year old female with a complex past medical history was transferred to our facility with chief complaint of worsening shock and respiratory failure, and the patient was also noted to be hypernatremic, experiencing diabetic ketoacidosis (DKA), and acute kidney injury (AKI). Her DKA resolved and hypernatremia and AKI began to improve. As a result, cefepime was dose-adjusted for renal function estimated by the Cockcroft-Gault (CG) equation. Her hospital course was complicated by persistent altered mental status (AMS), preventing extubation. Cefepime was discontinued due to concern for CIN, and a concentration was obtained 13-hours after the last dose which was elevated at 49 µg/mL. Two days following cefepime discontinuation, the patient's mental status improved allowing for successful extubation. The patient remained stable and was discharged to an acute care floor and then ultimately back to home. Conclusion: CIN should be part of a wider differential diagnosis for patients experiencing encephalopathy, and inaccurate renal function estimation may be a risk factor for developing CIN. Furthermore, therapeutic drug monitoring (TDM) may serve as an important clinical tool in diagnosing and managing CIN.

Initial trough concentration may be beneficial in preventing linezolid-induced thrombocytopenia

We assessed whether prospective therapeutic drug monitoring to optimise the therapeutic range could prevent linezolid-induced thrombocytopenia. This prospective interventional study was conducted from September 2017 to October 2020 among 37 adult patients receiving linezolid. Patients were administered one of the following two initial dosages: 600 mg twice or once daily for patients with a creatinine clearance rate of ≥50 or <50 mL/min, respectively. Linezolid dosage adjustment was performed on days 3-5 based on the trough concentration. The serum linezolid levels in 22 and 15 patients were within and above the therapeutic range (2-7 µg/mL), respectively. The incidence of thrombocytopenia was significantly lower among patients whose linezolid levels were within the therapeutic range (4.5%;1/22) than in those whose levels were above the therapeutic range (80%; 12/15). It is important to maintain the linezolid level within the therapeutic range at the first therapeutic drug monitoring to prevent thrombocytopenia.

Imeglimin population pharmacokinetics and dose adjustment predictions for renal impairment in Japanese and Western patients with type 2 diabetes

Imeglimin is an orally administered first-in-class drug to treat type 2 diabetes mellitus (T2DM) and is mainly excreted unchanged by the kidneys. The present study aimed to define the pharmacokinetic (PK) characteristics of imeglimin using population PK analysis and to determine the optimal dosing regimen for Japanese patients with T2DM and chronic kidney disease (CKD). Imeglimin plasma concentrations in Japanese and Western healthy volunteers, and patients with T2DM, including patients with mild to severe CKD with an estimated glomerular filtration rate (eGFR) > 14 mL/min/1.73 m² were included in a population PK analysis. Pharmacokinetic simulations were conducted using a population PK model, and the area under concentration-time curve (AUC) was extrapolated with power regression analysis to lower eGFR. The influence of eGFR, weight, and age on apparent clearance and of dose on relative bioavailability were quantified by population PK analysis. Simulations and extrapolation revealed that the recommended dosing regimen based on the AUC was 500 mg twice daily (b.i.d.) for patients with eGFR 15-45 mL/min/1.73 m² , and 500 mg with a longer dosing interval was suggested for those with eGFR < 15. Simulations revealed that differences in plasma AUCs between Japanese and Western patients at the same dose were mainly driven by a difference in the eGFR and that the plasma AUC after 1,000 and 1,500 mg b.i.d. in Japanese and Western patients, respectively, was comparable in the phase IIb studies. These results indicate suitable dosages of imeglimin in the clinical setting of T2DM with renal impairment.

Improving the risk-to-benefit ratio of inhaled corticosteroids through delivery and dose: current progress and future directions

INTRODUCTION

Inhaled corticosteroids (ICS) are known to increase the risk of systemic and local adverse effects, especially with high doses and long-term use. Hence, considerable resources are invested to improve pharmacokinetic/pharmacodynamic (PK/PD) properties of ICS, effective delivery systems and novel combination therapies to enhance the risk-to-benefit ratio of ICS.

AREAS COVERED

There is an unmet need for new solutions to achieve optimal clinical outcomes with minimal dose of ICS. This paper gives an overview of novel treatment strategies regarding the safety of ICS therapy on the basis of the three most recent molecules introduced to our everyday clinical practice - ciclesonide, mometasone furoate, and fluticasone furoate. Advances in aerosol devices and new areas of inhalation therapy are also discussed.

EXPERT OPINION

Current progress in improving the risk-to-benefit ratio of ICS through dose and delivery probably established pathways for further developments. This applies both to the improvement of the PK/PD properties of ICS molecules but also includes technical aspects that lead to simplified applicability of the device with simultaneous optimal drug deposition in the lungs. Indubitably, the future of medicine lies not only in the development of new molecules but also in technology and digital revolution.

Clinical pharmacist participation in selecting and dosing targeted drugs for a patient with ALK-positive non-small cell lung cancer: a case report

Ceritinib and alectinib are recommended as the second-line therapies in the 2019 Chinese Society of Clinical Oncology (CSCO) guidelines for patients with anaplastic lymphoma kinase (ALK) positive non-small-cell lung cancer (NSCLC) in whom the first-line therapy has failed, but no optimal second-line treatment has been identified. Before 2018, the approved dose of ceritinib in the United States and many other countries was 750 mg/d fasted. In China, the approved dose was 450 mg/d fed although the dose of 750 mg/d fasted is still used in clinical practices. In our current case, a clinical pharmacist was involved in the selection and dose adjustment of a targeted drug for an ALK-positive NSCLC patient. The selection of second-line targeted drugs is based mainly on the results of clinical trials and real-world data of ceritinib and aletinib, along with the comprehensive analysis of health insurance policy, pharmacoeconomics, and drug accessibility. Alectinib may be more efficacious than ceritinib is in second-line settings. However, in our current case, the patient finally chose ceritinib after considering the drug prices and the health insurance policy. The clinical pharmacist optimized the dosage of ceritinib from 750 mg/d fasted to 450 mg/d fed, which not only improved the patient’s medication compliance but also ensured the safety and efficacy of the drug; in addition, it lowered the financial burden of both the health insurance system and the patient, offering a good example for rational drug use and health insurance cost reduction. In conclusion, in choosing second-line targeted therapy for ALK-rearranged NSCLC, a variety of factors should be considered, including clinical efficacy, adverse effects, health insurance policy, drug price, and drug accessibility, and the dosage of ceritinib should be optimized to 450 mg/d fed in real-world settings.

Experience Using Ustekinumab in Pediatric Patients With Medically Refractory Crohn Disease

INTRODUCTION

Ustekinumab (UST), a human monoclonal antibody against interleukin-12 and 23, is approved to treat adult patients with psoriasis or Crohn disease (CD). Outcomes data for off-label use in pediatric patients with CD are limited.

AIM

We conducted a retrospective cohort study to analyze the long-term efficacy of UST, including dose adjustments, in the treatment of pediatric patients with medically refractory CD. Adverse events were documented.

METHODS

We identified 40 pediatric patients with CD treated with UST between January 1, 2016 and December 31, 2019. Electronic medical records were reviewed for demographics, Paris Classification, significant comorbidities, previous CD therapy, adverse events after initiation, and surveillance markers at the time of their first dose and most recent clinic visit. A validated abbreviated pediatric CD activity index (aPCDAI) was used to assess response to therapy.

RESULTS

Thirty-eight pediatric patients with CD, including 34.2% with stricturing or penetrating disease, were analyzed after initiation of treatment with UST. Median age at diagnosis of CD was 12.5 years, and median age at UST induction was 17.2 years. No patients were anti-TNF-naive, and 34.2% were previously exposed to 2 or more anti-TNF agents. At time of last follow-up, 84.2% of patients remained on UST for a median duration on UST of 62.1 weeks, and 60.5% achieved clinical remission. Patients had significant improvement in aPCDAI scores, clinical remission rates, albumin, and hematocrit, and 89.5% of patients had no significant adverse events. Similar results were observed among those who required dose adjustment, including 61.1% achieving clinical remission, and among those with perianal disease, including 38.5% achieving clinical remission.

CONCLUSIONS

Our data suggest that, within our cohort of pediatric patients with CD, UST has long-term efficacy with no observed safety concerns. Dose adjustment may be helpful in achieving clinical remission.

Impact of Infliximab Biosimilar CT-P13 Dose and Infusion Interval on Real-World Drug Survival and Effectiveness in Patients with Ankylosing Spondylitis

CT-P13 is an infliximab biosimilar approved for indications including ankylosing spondylitis (AS); the approved maintenance regimen is 5 mg/kg infused every 6–8 weeks. In clinical practice, modifications to infliximab dose and/or infusion interval can be beneficial to the patient. For CT-P13, real-world data on dose and/or interval adjustment are lacking. This analysis investigated the impact of such treatment pattern changes on effectiveness and drug survival up to five years for adult (≥18 years old) patients with AS in the Korean, real-world, retrospective rheumatoid arthritis and ankylosing spondylitis (RAAS) study. Overall, 337 patients with AS were identified: 219 who initiated infliximab treatment with CT-P13 (‘naïve’) and 118 who switched from reference infliximab to CT-P13 (‘switched’). Overall, 18/235 (7.7%), 110/224 (49.1%), and 101/186 (54.3%) evaluable patients had dose, infusion interval, or combined treatment pattern changes, respectively. More naïve (61.0%) versus switched (42.6%) patients had treatment pattern changes. Overall, Bath Ankylosing Spondylitis Disease Activity Index scores decreased from baseline to week 54, then remained stable; improvements were greater for patients with than without treatment pattern changes. Drug survival did not differ significantly between patients with or without treatment pattern changes. Findings suggest that adjusting dose and/or infusion interval can improve clinical outcomes for CT-P13-treated patients with AS.

Reinforcement Learning for Precision Oncology

Precision oncology is grounded in the increasing understanding of genetic and molecular mechanisms that underly malignant disease and offer different treatment pathways for the individual patient. The growing complexity of medical data has led to the implementation of machine learning techniques that are vastly applied for risk assessment and outcome prediction using either supervised or unsupervised learning. Still largely overlooked is reinforcement learning (RL) that addresses sequential tasks by exploring the underlying dynamics of an environment and shaping it by taking actions in order to maximize cumulative rewards over time, thereby achieving optimal long-term outcomes. Recent breakthroughs in RL demonstrated remarkable results in gameplay and autonomous driving, often achieving human-like or even superhuman performance. While this type of machine learning holds the potential to become a helpful decision support tool, it comes with a set of distinctive challenges that need to be addressed to ensure applicability, validity and safety. In this review, we highlight recent advances of RL focusing on studies in oncology and point out current challenges and pitfalls that need to be accounted for in future studies in order to successfully develop RL-based decision support systems for precision oncology.

An Unusual Neurological Syndrome in a Haemodialysis Patient

Advanced age and immunosuppressed states allow for complications of herpes zoster such as encephalitis. In this case report, we describe a patient with encephalopathy two days after initiation of antiviral therapy. After the necessary imaging and cerebrospinal fluid (CSF) analysis, it became evident that the neurological syndrome was due to acyclovir. Despite currently practised renal dose modification, the patient developed acyclovir-induced neurotoxicity and required intensification of his dialysis schedule to eliminate the drug. Acyclovir-induced neurotoxicity is a rare clinical presentation and presents a clinical dilemma to the physician who has to distinguish this entity from herpes zoster encephalitis and posterior circulation stroke.

Principles of Kidney Pharmacotherapy for the Nephrologist: Core Curriculum 2021

Medications are an important part of the management of patients with kidney disease. When used appropriately, pharmacotherapy can slow disease progression and reduce morbidity and mortality. Unfortunately, reduced kidney function can significantly alter the pharmacokinetics and pharmacodynamics of many medications, putting patients at risk for drug toxicity if modifications to therapy are not appropriately managed. Adding complexity to the appropriateness of medication and dosage selection is the difficulty in estimating kidney function and the discordance between the Cockcroft-Gault-derived dosing cut points in most medication package inserts and the estimations of glomerular filtration rate by newer and generally more accurate guideline-recommended equations. This installment of the AJKD Core Curriculum in Nephrology provides recent updates and practical considerations for designing optimal medication regimens. Given the prevalence of abnormal kidney function and its importance in medication selection and dose adjustment, additional focus and specific recommendations are provided for anticoagulant, anti-infective, analgesic, antidiabetic, and antihypertensive agents.

The effect of a Clinical Decision Support System on the frequency of dose adjustments of anticancer drugs in case of renal or hepatic dysfunction

INTRODUCTION

Dose adjustments in patients with renal or hepatic dysfunction using anticancer drugs are indicated according to guidelines. However, implementation depends on awareness of prescribing physicians. We implemented a Clinical Decision Support System (CDSS), recommending dose adjustments upon electronic prescriptions based on renal and hepatic function. The alert provides a dose adjustment proposal and recent laboratory results. Our objective was to determine the frequency of dose adjustments before and after implementation of this CDSS.

METHODS

We included all first orders for patients ≥18 years treated with parenteral antineoplastic agents, for whom dosage adjustment is necessary based on renal or hepatic function between February 2018 and January 2019. This study was performed at the department of Clinical Oncology and Hematology of the Amsterdam University Medical Center. We implemented the CDSS August first. All prescriptions were prescribed according to common practice. We analyzed the orders where a dose reduction based on renal or hepatic function was indicated.

RESULTS

We included 73 orders before implementation and 99 orders after implementation. Before implementation 21% of doses were reduced in line with the guidelines versus 34% after implementation (p = 0.048). For hepatic dysfunction the proportion changed from 11% to 46% p = 0.011, while there was no effect for renal dysfunction (24% vs. 26% p = 0.75).

CONCLUSION

Dosages are more frequently adjusted in concordance with guidelines in patients with hepatic dysfunction who are treated with parenteral antineoplastic agents after implementation of a CDSS. The change was not seen in patients with renal dysfunction.

Use of medicines for covid-19 treatment in patients with loss of kidney function: a narrative review

Covid-19 has been identified as the cause of acute respiratory disease with interstitial and alveolar pneumonia, but it can affect several organs, such as kidneys, heart, blood, nervous system and digestive tract. The disease-causing agent (Sars-CoV-2) has a binding structure to the angiotensin-converting enzyme 2 (ACE2) receptor, enabling entry into cells that express ACE2, such as the pulmonary alveolar epithelial cells. However, studies also indicate the possibility of damage to renal cells, since these cells express high levels of ACE2. Currently, there is no evidence to indicate a specific treatment for covid-19. Several drugs have been used, and some of them may have their excretion process altered in patients with abnormal kidney function. To date, there are no studies that assist health professionals in adjusting the dose of these drugs. Thus, this study aims to review and discuss the topic, taking into account factors associated with kidney injury in covid-19, as well as pharmacokinetic aspects and dose recommendations of the main drugs used for covid-19.

Effective Treatment of Neurological Symptoms with Normal Doses of Botulinum Neurotoxin in Wilson's Disease: Six Cases and Literature Review

Recent cell-based and animal experiments have demonstrated an effective reduction in botulinum neurotoxin A (BoNT/A) by copper. Aim: We aimed to analyze whether the successful symptomatic BoNT/A treatment of patients with Wilson’s disease (WD) corresponds with unusually high doses per session. Among the 156 WD patients regularly seen at the outpatient department of the university hospital in Düsseldorf (Germany), only 6 patients had been treated with BoNT/A during the past 5 years. The laboratory findings, indications for BoNT treatment, preparations, and doses per session were extracted retrospectively from the charts. These parameters were compared with those of 13 other patients described in the literature. BoNT/A injection therapy is a rare (<4%) symptomatic treatment in WD, only necessary in exceptional cases, and is often applied only transiently. In those cases for which dose information was available, the dose per session and indication appear to be within usual limits. Despite the evidence that copper can interfere with the botulinum toxin in preclinical models, patients with WD do not require higher doses of the toxin than other patients with dystonia.

Are vancomycin dosing guidelines followed? A mixed methods study of vancomycin prescribing practices

AIMS

Despite the availability of international consensus guidelines, vancomycin dosing and therapeutic drug monitoring (TDM) remain suboptimal. This study aimed to assess concordance of vancomycin dosing and TDM with institutional guidelines and to identify factors taken into consideration by clinicians when prescribing vancomycin.

METHODS

A retrospective audit of 163 patients receiving vancomycin therapy (≥48 hours) was undertaken. Data collected included patient characteristics, dosing history and plasma vancomycin and creatinine concentrations. Concordance of dosing and TDM with institutional guidelines was evaluated. Semi-structured interviews, including simulated prescribing scenarios, were undertaken with prescribers (n = 17) and transcripts analysed.

RESULTS

Plasma vancomycin concentrations (n = 1043) were collected during 179 courses of therapy. Only 24% of courses commenced with a loading dose with 72% lower than recommended. The initial maintenance dose was concordant in 42% of courses with 34% lower than recommended. Only 14% of TDM samples were trough vancomycin concentrations. Dose was not adjusted for 60% (21/35) of subtherapeutic and 43% (18/42) of supratherapeutic trough vancomycin concentrations, respectively. Interview participants reported that patient characteristics (including renal function), vancomycin concentrations, guidelines and expert advice influenced vancomycin prescribing decisions. Despite referring to guidelines when completing simulated prescribing scenarios, only 37% of prescribing decisions aligned with guideline recommendations.

CONCLUSION

Poor compliance with institutional vancomycin guidelines was observed, despite prescriber awareness of available guidelines. Multifaceted strategies to support prescriber decision-making are required to improve vancomycin dosing and monitoring.

Assessment of Medication Dosage Adjustment in Hospitalized Patients With Chronic Kidney Disease

Background Inappropriate medication dosing can cause adverse drug reactions or ineffective therapy due to declined renal function in patients with renal insufficiency. This necessitates proper renal dose adjustment. This study was proposed to evaluate medication dosage adjustment in hospitalized chronic kidney disease (CKD) patients. Methods This study included all CKD patients hospitalized between May 1, 2019, and April 25, 2020, at the Institute of Kidney Disease, Peshawar, Pakistan. The estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease formula, and dose appropriateness was established by evaluating practice with relevant reference books. Results Of the total 1,537 CKD patients, 231 (15.03%) had evidence of dosing error, which was considered for final analysis. Overall, 1,549 drugs were prescribed; 480 (30.99%) drugs required dose adjustment, of which 196 (40.42%) were adjusted properly and the remaining 286 (59.58%) were unadjusted. The most common unadjusted drugs were meropenem, cefepime, ciprofloxacin, and rosuvastatin, whereas captopril, aspirin, bisoprolol, pregabalin, and levofloxacin had the highest percentage of adjusted drugs. On multivariate logistic regression, the number of drugs requiring dosing adjustments and obstructive nephropathy were found to be statistically significant factors that increased the likelihood of the medication dosing errors: a unit increase in the number of drugs requiring dose adjustment increases 5.241 times the likelihood of dosing error. Similarly, the presence of obstructive nephropathy (OR: 0.383; 95% Cl: 0.153-0.960; p = 0.041) was found to be significantly associated with dosing error after adjustment for potential confounding factors. Conclusion The dosing of more than half of the prescribed drugs that required adjustment in CKD patients was not adjusted, which showed that medication dosing errors were high. This highlights the importance of medication prescription according to guidelines in these patients to improve the outcomes of pharmacotherapy.

A Novel Creatinine-Based Equation to Estimate Glomerular Filtration Rate in Chinese Population With Chronic Kidney Disease: Implications for DOACs Dosing in Atrial Fibrillation Patients

Background: Over/under-estimating renal function may increase inappropriate dosing strategy associated adverse outcomes; however, previously reported equations to estimate renal function have limited accuracy in chronic kidney disease (CKD) patients. Consequently, we intended to develop a novel equation to precisely estimate renal function and subsequently guide clinical treatment for CKD patients.

Methods: A novel approach, Xiangya-s equation, to estimate renal function for CKD patients was derived by linear regression analysis and validated in 1885 patients with measured glomerular filtration rate (mGFR) < 60 ml/min/1.73 m² by renal dynamic imaging at three representative hospitals in China, with the performance evaluated by accuracy, bias and precision. In the meanwhile, 2,165 atrial fibrillation (AF) patients who initiated direct oral anticoagulants (DOACs) between December 2015 and December 2018 were identified and renal function was assessed by estimated creatinine clearance (eCrCl). Events per 100 patient-years was calculated. Cox proportional hazards regression was applied to compare the incidence of outcomes of each group.

Results: Xiangya-s equation demonstrated higher accuracy, lower bias and improved precision when compared with 12 creatinine-based and 2 CysC-based reported equations to estimate GFR in multi-ethnic Chinese CKD patients. When we applied Xiangya-s equation to patients with AF and CKD prescribed DOACs, wide variability was discovered in eCrCl calculated by the Cockcroft-Gault (CG), Modification of Diet in Renal Disease Study (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Xiangya equation which we had developed for generally patients and Xiangya-s equations, which persisted after grouping by different renal function stages. Equation choice affected drug-dosing adjustments, with the formulas agreeing for only 1.19%, 5.52%, 33.22%, 26.32%, and 36.61% of potentially impacted patients for eCrCl cutoffs of <15, <30, 15–49, 30–49, ≥50 ml/min, respectively. Relative to CG equation, accordance in DOACs dosage was 81.08%, 88.54%, 62.25%, and 47.68% for MDRD, CKD-EPI, Xiangya and Xiangya-s equations for patients with CrCl < 50 ml/min (eCrCl cutoffs of <30, 30–49, ≥50 ml/min), respectively. Reclassification of renal function stages by Xiangya-s equation was significantly associated with stroke or systemic embolism, non-major clinically relevant bleeding and any bleeding events.

Conclusion: Xiangya-s equation provides more accurate GFR estimates in Chinese CKD patients who need consecutive monitoring of renal function, which may assist clinicians in choosing appropriate drug dosages.

The art and science of drug titration

A “one-size-fits-all” approach has been the standard for drug dosing, in particular for agents with a wide therapeutic index. The scientific principles of drug titration, most commonly used for medications with a narrow therapeutic index, are to give the patient adequate and effective treatment, at the lowest dose possible, with the aim of minimizing unnecessary medication use and side effects. The art of drug titration involves the interplay of scientific drug titration principles with the clinical expertise of the healthcare provider, and an individualized, patient-centered partnership between the provider and the patient to review the delicate balance of perceived benefits and risks from both perspectives. Drug titration may occur as up-, down-, or cross-titration depending on whether the goal is to reach or maintain a therapeutic outcome, decrease the risk of adverse effects, or prevent withdrawal/discontinuation syndromes or recurrence of disease. Drug titration introduces additional complexities surrounding the conduct of clinical trials and real-world studies, confounding our understanding of the true effect of medications. In clinical practice, wide variations in titration schedules may exist due to a lack of evidence and consensus on titration approaches that achieve an optimal benefit-harm profile. Further, drug titration may be challenging for patients to follow, resulting in suboptimal adherence and may require increased healthcare-related visits and coordination of care amongst providers. Despite the challenges associated with drug titration, it is a personalized approach to drug dosing that blends science with art, and with supportive real-world outcomes-based evidence, can be effective for optimizing pharmacotherapeutic outcomes and improving drug safety.

Dose Adjustment Model of Paliperidone in Patients With Acute Schizophrenia: A post hoc Analysis of an Open-Label, Single-Arm Multicenter Study

This study aimed to investigate the factors that influenced the clinicians to adjust the paliperidone dose in the acute phase of schizophrenia. This was a post hoc study of an 8-week, open-label, single-arm multicenter trial which evaluated the efficacy, safety, and tolerability of flexible doses of paliperidone ER (3-12 mg/day) in patients with acutely exacerbated schizophrenia. Patients were divided into groups according to the dose at week 8 (3, 6, and 9-12 mg). The responder was defined as the reduction percentage in the Positive and Negative Syndrome Scale (PANSS) total score of ≥30%. According to the chi-squared automatic interaction detection algorithm, decision tree models predicting an increase in the dose of paliperidone ER were established. A decision tree, based on 4-week Marder positive factor, Clinical Global Impression (CGI), and BMI, was established to guide the dose adjustments of paliperidone ER in the acute phase of schizophrenia. The multivariable logistic regression analysis showed that lower age at onset, higher baseline PANSS positive subscale score, and lower baseline Personal and Social Performance Scale (PSP) score were significant predictors of increased dose in responders. Patients with young-onset age, severe baseline symptoms, and poor function are more likely to benefit from high dosage.

Dose adjustment for tyrosine kinase inhibitors in non‑small cell lung cancer patients with hepatic or renal function impairment (Review)

In recent years, a number of tyrosine kinase inhibitors (TKIs) have been approved for the treatment of non-small cell lung cancer. These novel treatments exhibit improved efficacy and toxicity when compared to conventional chemotherapy agents. TKIs are administered orally, which has the advantages of improved flexibility and convenience for the patients. However, challenges have arisen in the use of these novel agents. Prescribing drugs for patients with hepatic or renal function impairment poses a challenge for clinicians due to the large pharmacokinetic variability in each individual patient. Moreover, several TKIs have been shown to cause laboratory test abnormalities normally associated with hepatic or renal injury. The aim of the present review was to discuss the effects of hepatic and renal function impairment on the pharmacokinetic variability of 17 TKIs and their potential hepatotoxicity and nephrotoxicity, and to recommend dose adjustment for patients with hepatic or renal impairment.

Pharmacokinetic Considerations in Amputees

PURPOSE

The purpose of this article is to review the currently available assessment tools for measuring renal function, body weight, and body surface area in the amputee population.

METHODS

PubMed and Web of Science were searched using the following key terms: amputation, dose adjustment, and estimation of body weight. Articles published in languages other than English were excluded from the search.

RESULTS

Despite the increasing prevalence of amputations, there is little literature available that discusses its impact on the patient and how these physiological changes can affect pharmacokinetics. Very little information is available to guide dose adjustment in this patient population. This article discusses several factors to consider when determining optimum dosing regimens in patients with different levels of amputations.

CONCLUSION

This article will evaluate the applicability of methods mentioned in existing literature for measuring changes in renal function, body weight, and body surface area in amputees.

Mirogabalin in Japanese Patients with Renal Impairment and Pain Associated with Diabetic Peripheral Neuropathy or Post-Herpetic Neuralgia: A Phase III, Open-Label, 14-Week Study

Purpose

Mirogabalin was recently approved in Japan for the treatment of peripheral neuropathic pain, based on data from clinical trials in diabetic peripheral neuropathic pain (DPNP) and post-herpetic neuralgia (PHN), common clinical conditions which cause intense distress for patients. We characterized the safety and tolerability of mirogabalin in Japanese patients with renal impairment.

Patients and Methods

This multicenter, open-label study (ClinicalTrials.gov identifier NCT02607280) enrolled renally impaired individuals aged ≥20 years diagnosed with DPNP or PHN, and with an average daily pain score (ADPS) of ≥4 over the 7 days prior to treatment initiation. Mirogabalin dosage was titrated for 2 weeks, followed by a fixed dose for 12 weeks according to degree of renal impairment: 7.5 mg twice daily for moderate impairment and 7.5 mg once daily for severe impairment. The primary endpoint was safety and tolerability of mirogabalin, evaluated via treatment-emergent adverse events (TEAEs). Secondary efficacy endpoints included change in ADPS from baseline to Week 14.

Results

Overall, 35 patients were enrolled (30 with moderate and 5 with severe renal impairment). Most TEAEs were mild or moderate in severity; the most commonly reported were nasopharyngitis (22.9%) and somnolence (11.4%). Only 4 patients (11.4%) discontinued treatment due to TEAEs. Mirogabalin significantly decreased ADPS from baseline in patients with renal impairment; least squares mean change from baseline at Week 14 was −1.9 (95% confidence interval: −2.8, −1.0).

Conclusion

Mirogabalin was well tolerated and significantly reduced pain levels when used to treat DPNP/PHN at a fixed dose of 7.5 mg once or twice daily in patients with renal impairment.

Recent trends in tablet subdivision and factors affecting subdivision in South Korea: A cross-sectional study

Tablet subdivision by physicians or patients frequently occurs in various clinical settings for multiple reasons, including dose adjustment, alleviation of swallowing difficulties, or cost savings. However, not all tablets are suitable for subdivision, and it might cause side effects. It is informative to know which medicines are regularly subdivided, which healthcare institutions prescribe subdivided medicines, and to whom the medicines are prescribed from the perspectives of quality of care and patient safety. In this study, we aimed to examine recent trends in tablet subdivision and to address factors associated with subdivision of tablets both at the patient and healthcare institution levels.The yearly claims data in 2016 retrieved from the National Patients Sample provided by the Health Insurance Review and Assessment (HIRA-NPS). This study used descriptive statistics to examine characteristics of medicines that were frequently prescribed in subdivided forms, and retrieved information regarding the medicines to assess the appropriateness for tablet splitting. Then, we selected five medicines, and performed a multivariate logistic regression analysis to estimate the effect of the variables of interest on tablet subdivision.We presented the top 25 medicines prescribed in subdivided forms in 2016, and confirmed these medicines could be relevantly halved according to their Summary of Product Characteristics. Of the 25 medicines, 14 (56%), 5 (20%), and 3 (12%) medicines belonged to the respiratory system (R), nervous system (N), and systemic hormonal preparations (H), according to the first category of Anatomical Therapeutic Chemical (ATC) classification system, respectively. Being female at the patient level and tertiary healthcare institutions and private owned institutions at the institution level were positively associated with subdivision of medicines.Subdivision of tablets frequently occurred for vulnerable populations with various reasons. Female and geriatric patients are prescribed split medicines for clinical reasons, while low-income patients are prescribed nonsplit medicines for cost savings. It would be better if medicines were not so small, and if they had dividing lines on their surfaces to enable successful splitting of the tablet and to protect the health of vulnerable patients. Furthermore, avoid splitting those pharmacotherapies with a narrow therapeutic range, and provide a pharmacist assistance and a splitting device for unavoidable splitting.

Pharmacokinetic and Pharmacodynamic Profiles of Cefiderocol, a Novel Siderophore Cephalosporin

Cefiderocol, a novel parenteral siderophore cephalosporin, exhibits potent in vitro activity and in vivo efficacy against most gram-negative bacteria, including carbapenem-resistant strains of Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. In phase 1 studies, cefiderocol demonstrated linear pharmacokinetics, primarily urinary excretion, an elimination half-life of 2-3 hours, and a protein binding of 58% in human plasma. Cefiderocol is a time-dependent cephalosporin; the probability of a target attainment at ≥75% of the dosing interval during which the free drug concentration exceeds the minimum inhibitory concentration (ƒT/MIC) for bacterial strains with an MIC of ≤4 μg/mL is likely to be achieved at the therapeutic dose of 2 g over 3-hour infusion every 8 hours in most patients. As expected, renal function markers were the most influential covariates for the pharmacokinetics of cefiderocol for patients with renal impairment or augmented renal clearance (ARC). Dose adjustment is recommended for patients with impaired renal function, and additionally, in ARC patients with creatinine clearance >120 mL/minute, a more frequent dosing regimen (ie, 2 g every 6 hours) was predicted to achieve the target fT > MIC. The single and multiple doses of cefiderocol tested were well tolerated in both healthy subjects and those with renal impairment. Furthermore, neither QT interval prolongation nor drug-drug interaction via organic anion transporters was demonstrated in healthy subjects. Cefiderocol is being investigated in phase 3 clinical studies for the treatment of infections caused by carbapenem-resistant bacteria.

Individualized Treatment Analysis Of Breast Cancer With Chronic Renal Failure

We report the case of a breast cancer patient with chronic renal failure (CRF). The clinical pharmacist adjusted the chemotherapy regimen and dosage according to the patient’s renal function after reviewing the literature and analyzing the pharmacological and pharmacokinetic characteristics of the patient’s antineoplastic drugs. To the best of our knowledge, this is the first report of successful multimodal treatment of breast cancer in a patient with CRF in China. The purpose of this case report is to optimize breast cancer therapy in patients with CRF and provide a reference for clinicians and clinical pharmacists to use antineoplastic drugs rationally.

Effect of NUDT15 on incidence of neutropenia in children with acute lymphoblastic leukemia

BACKGROUND

6-Mercaptopurine (6-MP) is considered the backbone of therapy in the maintenance phase of acute lymphoblastic leukemia (ALL). Gene polymorphisms involved in thiopurine degradation are predictors of toxicity in patients treated with 6-MP. We investigated the effects of nucleoside diphosphate linked moiety X (nudix) type motif 15 (NUDT15) polymorphism NUDT15c.415C>T on neutropenia incidence, dose adjustment for 6-MP, and survival rates in Thai children with ALL.

METHODS

Children diagnosed with ALL who received 6-MP in the maintenance phase of treatment, in 2005-2016, were retrospectively enrolled.

RESULTS

The subjects consisted of 102 patients (median age, 5.2 years; 58 boys). On genetic testing 78, 22, and two patients were normal (CC), heterozygous (CT), and homozygous (TT), respectively. The incidence of neutropenia at 3 months was significantly higher in the CT/TT than CC polymorphism groups (OR, 12; 95%CI: 3.781-38.085, P < 0.001). The mean dose of 6-MP at 3, 6, and 12 months was significantly lower in the CT/TT versus the CC group (P < 0.001). The 5 year overall survival (OS) rate for CC was 80.4%, and for CT/TT, 95.5% (P = 0.34). The 5 year event-free survival (EFS) for CC and CT/TT was 75.1% and 85.7%, respectively (P = 0.17). After adjusted risk classification, no significant differences were observed for OS or EFS between the CC and CT/TT groups.

CONCLUSION

Patients harboring the CT/TT polymorphism of NUDT15 had a significantly higher incidence of neutropenia during the first 3 months of maintenance, resulting in significantly lower doses of 6-MP.

Dual therapy with renally adjusted lamivudine and dolutegravir: a switch strategy to manage comorbidity and toxicity in older, suppressed patients?

OBJECTIVES

The aim of the study was to evaluate the efficacy of dual therapy with lamivudine (3TC), with dose adjustment for renal function, and dolutegravir (DTG) in a subgroup of patients fully suppressed on treatment who were switched because of concerns about comorbidity and toxicity on their current triple drug regimen.

METHODS

A retrospective evaluation of clinical and pathological parameters from an electronic patient record from a single centre was carried out.

RESULTS

There were no virological failures in 52 patients with a median age of 60.5 years. The median duration of follow-on dual therapy was 2.29 years (28 months; range 1.10-3.34 years). In 25 of 52 (48%) cases, the dose of 3TC was adjusted taking into account reduced renal function, and none of these patients experienced virological failure. Four additional patients discontinued early, because of side effects of the switch, with no failure.

CONCLUSIONS

This retrospective review suggests that 3TC and DTG may be effective in controlling viral load in older patients with comorbidities. This regimen appears to be a useful option in the context of comorbidities (including renal impairment) and polypharmacy in older patients. However, this review has been conducted in one centre and in a small population of patients. Therefore, further multicentre trials involving larger populations of patients are needed.

Infliximab dose adjustment can improve the clinical and radiographic outcomes of rheumatoid arthritis patients: REVIVE study results

Purpose

We evaluated the clinical responses and radiographic outcomes of 90 patients with rheumatoid arthritis (RA) undergoing continuous or dose-adjusted infliximab treatment over 104 weeks.

Patients and methods

Patients received 3 mg/kg infliximab continuously (the contin group; n=50), or the dose escalation and de-escalation of infliximab (3, 6, and 10 mg/kg) from week 14 (the adjusted group; n=40) based on the patient’s Disease Activity Score in 28 joints (DAS28). The retention rate, clinical response, and radiographic assessment were determined at week 104.

Results

The contin and adjusted groups’ retention rates at week 104 were 56.8 and 66.7%, and the groups’ low disease activity in the DAS28 was 39.1 and 66.7%, respectively. Remission based on the DAS28 and the American College of Rheumatology (ACR)/European League against Rheumatism (EULAR) Boolean-based criteria was significantly increased in the adjusted group. In the radiographic assessment, there was also a significant reduction in the mean changes in total Sharp score. The cumulative rates of any adverse effects showed no significant difference between the groups.

Conclusion

In an assessment of adequate DAS28 results, the RA patients who did not respond to the initial dose of infliximab showed improved clinical responses and radiographic assessment after a dose adjustment of infliximab, without an increased risk of serious adverse events.

Pharmacokinetics of Toxin-Derived Peptide Drugs

Toxins and venoms produced by different organisms contain peptides that have evolved to have highly selective and potent pharmacological effects on specific targets for protection and predation. Several toxin-derived peptides have become drugs and are used for the management of diabetes, hypertension, chronic pain, and other medical conditions. Despite the similarity in their composition (amino acids as the building blocks), toxin-derived peptide drugs have very profound differences in their structure and conformation, in their physicochemical properties (that affect solubility, stability, etc.), and subsequently in their pharmacokinetics (the processes of absorption, distribution, metabolism, and elimination following their administration to patients). This review summarizes and critically analyzes the pharmacokinetic properties of toxin-derived peptide drugs: (1) the relationship between the chemical structure, physicochemical properties, and the pharmacokinetics of the specific drugs, (2) the major pharmacokinetic properties and parameters of these drugs, and (3) the major pharmacokinetic variability factors of the individual drugs. The structural properties of toxin-derived peptides affect their pharmacokinetics and pose some limitations on their clinical use. These properties should be taken into account during the development of new toxin-derived peptide drugs, and for the efficient and safe use of the clinically approved drugs from this group in the individual patients.

Pharmacokinetics and Safety of Omadacycline in Subjects with Impaired Renal Function

Many antibiotics require dose adjustments in patients with renal impairment and/or in those undergoing hemodialysis. Omadacycline, the first aminomethylcycline antibiotic in late-stage clinical development, displays activity against a broad spectrum of bacterial pathogens, including drug-resistant strains. Data from completed phase 3 studies of omadacycline for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP) showed intravenous (i.v.) to once-daily oral omadacycline to be clinically effective and well tolerated. To determine if the dosing of omadacycline should be adjusted in patients with impaired renal function, a phase 1 study examining the pharmacokinetics (PK) and safety of i.v. omadacycline (100 mg) was conducted in subjects with end-stage renal disease (ESRD) on stable hemodialysis (n = 8) and in matched healthy subjects (n = 8). i.v. administration of omadacycline produced similar plasma concentration-time profiles in subjects with ESRD and healthy subjects. Further, in subjects with ESRD, similar values of the PK parameters were observed when omadacycline was administered i.v. after or before dialysis. The mean area under the concentration-time curve from time zero extrapolated to infinity in plasma was 10.30 μg · h/ml when omadacycline was administered to ESRD subjects after dialysis, 10.20 μg · h/ml when omadacycline was administered to ESRD subjects before dialysis, and 9.76 μg · h/ml when omadacycline was administered to healthy subjects. The mean maximum observed concentration of omadacycline in plasma in ESRD subjects was 1.88 μg/ml when it was administered after dialysis and 2.33 μg/ml when it was administered before dialysis, and in healthy subjects it was 1.92 μg/ml. The 100-mg i.v. dose of omadacycline was generally safe and well tolerated in both ESRD and healthy subjects. This study demonstrates that no dose adjustment is necessary for omadacycline in patients with impaired renal function or on days when patients are receiving hemodialysis.

No Effect of Dose Adjustment to the CYP2D6 Genotype in Patients With Severe Mental Illness

Background: The CYP2D6 enzyme is involved in the metabolism of numerous psychopharmacological drugs. Guidelines recommend how to adjust the dose of medication based on the CYP2D6 genotype. Aims: To evaluate the effect of dose adjustment to the CYP2D6 genotype and phenotype, in patients with severe mental illness (SMI) already receiving psychopharmacological treatment. Methods: A total of 269 psychiatric patients (on the island Curaçao) receiving antipsychotic treatment were genotyped for CYP2D6. Of these, 45 patients were included for dose adjustment according to the clinical guideline of the Royal Dutch Association for the Advancement of Pharmacy, i.e., 17 CYP2D6 poor metabolizers, 26 intermediate metabolizers, and 2 ultrarapid metabolizers. These 45 patients were matched for age, gender, and type of medication with a control group of 41 patients who were CYP2D6 extensive metabolizers (i.e., with a normal CYP2D6 function). At baseline and at 4 months after dose adjustment, subjective experience, psychopathology, extrapyramidal side-effects, quality of life, and global functioning were assessed in these two groups. Results: At baseline, there were no differences between the groups regarding the prescribed dosage of antipsychotics, the number of side-effects, psychiatric symptoms, global functioning, or quality of life. After dose adjustment, no significant improvement in these parameters was reported. Conclusion: In psychiatric patients with SMI already receiving antipsychotic treatment, dose adjustment to the CYP2D6 genotype or phenotype according to the guidelines showed no beneficial effect. This suggests that dose adjustment guidelines are currently not applicable for patients already using antipsychotics. ClinicalTrials.gov: Cost-effectiveness of CYP2D6 and CYP2C19 Genotyping in Psychiatric Patients in Curacao; Identifier: NCT02713672; https://clinicaltrials.gov/ct2/show/NCT02713672?term=CYP2D6&rank=5.

Managing multiple myeloma in elderly patients

Multiple myeloma (MM) is a plasma cell neoplasm that affects elderly individuals with two-thirds of patients over 65 years at diagnosis. However, data available are derived from clinical trials conducted in younger patients. Fewer studies investigated treatment options in the elderly. This review summarizes the clinical outcomes and toxicities associated with therapeutic regimens in older patients including doublet, triplet and high dose therapyin newly diagnosed patients and relapsed patients with MM. We highlight the importance of an approach tailored to individuals, incorporates the geriatric frailty assessment, considers comorbiditiess and commits to early recognition and management of toxicities ranging from myelosuppression to polypharmacy. To date, no trial has prospectively investigated a tailored treatment paradigm in older patients based on frailty and/or comorbidities. As the population ages, the proportion of MM patients with advanced age will grow. Studies are indicated to determine optimal treatment approaches in this increasingly heterogeneous geriatric population.

Clinical Outcome and Antimicrobial Therapeutic Drug Monitoring for the Treatment of Infections in Acute Burn Patients

PURPOSE

In critical burn patients, the pharmacokinetic parameters (absorption, distribution, metabolism, and excretion) of many classes of drugs, including antibiotics, are altered. The aim of this study was to compare 2 groups of burn patients undergoing treatment for health care-associated infections with and without therapeutic drug monitoring.

METHODS

A retrospective analysis of a clinical intervention (ie, a before/after study) was conducted with patients with health care-associated pneumonia, burn infection, bloodstream infection, and urinary tract infection in the burn intensive care unit of a tertiary care hospital. The patients were divided into 2 groups: (1) those admitted from May 2005 to October 2008 who received conventional antimicrobial dose regimens; and (2) those admitted from November 2008 to June 2011 who received antibiotics (imipenem, meropenem, piperacillin, and vancomycin) with doses adjusted according to plasma monitoring and pharmacokinetic modeling. General characteristics of the groups were analyzed, as were clinical outcomes and 14-day and in-hospital mortality.

FINDINGS

Sixty-three patients formed the conventional treatment group, and 77 comprised the monitored treatment group. The groups were homogeneous, median age was 31 years (range: 1-90) and 66% were male. Improvement occurred in 60% of the patients under monitored treatment (vs 52% with conventional treatment); 14-day mortality was 16% vs 14%; and the in-hospital mortality was similar between groups (39% vs 36%). In the final multivariate models, variables significantly associated with in-hospital mortality were total burn surface area ≥30%, older age, and male sex. Treatment group did not affect the prognosis.

IMPLICATIONS

Therapeutic drug monitoring of antimicrobial treatment did not alter the prognosis of these burn patients. More trials are needed to support the use of therapeutic drug monitoring to optimize treatment in burn patients.

Inappropriate Medication in Non-Hospitalized Patients With Renal Insufficiency: A Systematic Review

OBJECTIVES

Renal insufficiency is common among older patients and, accordingly, renally excreted drugs may require an adjustment in dosage for them. Rates of non-adherence to renal dosing guidelines range from 19% to 70% across all settings, with the highest rate occurring in outpatient care. However, there is a paucity of research in this field. The main objective of this systematic review is to assess how often drugs are inappropriately prescribed in non-hospitalized patients with renal insufficiency.

DESIGN

A systematic literature search was performed. Data were identified from three electronic databases: PubMed, CINAHL, and Scopus. Studies were included if they reported quantitative data on inappropriate drug use with respect to renal function in non-hospitalized patients.

RESULTS

Our search strategy resulted in 2,403 hits, of which 18 articles satisfied the criteria for inclusion. Mean estimated glomerular filtration rate ranged from 36.0 to 60.4 mL/min. Prevalence of renally inappropriate drug use ranged from 1% to 37% in outpatient settings other than nursing homes, and from 6% to 43% in nursing homes. Eight of the studies we included identified predictors for use of drugs inappropriate for kidney function. Most frequently determined risk factors were increasing age and a high number of prescribed drugs.

CONCLUSION

Lack of dose adjustment for renal impairment seems to be a common problem, even in outpatients. However, the differences in methodologies used in these studies hampered any direct comparison. Accepted and comparable standards regarding the drugs included in the studies as well as estimation of renal function would be beneficial.