A Phase 1 Study of Intravenous Busulfan as a Conditioning Regimen for Multiple Myeloma

The efficacy of melphalan (MEL) 140 mg/m 2 pre-transplant conditioning versus MEL 200 mg/m 2 for the elderly is still debated. We hypothesized that single-agent intravenous busulfan (BU) would show significant anti-myeloma efficacy and be better tolerated by elderly patients. A prospective 3+3 dose escalation study enrolled symptomatic multiple myeloma (MM) patients 65 years or older with SWOG performance 0–2 for treatment with intravenous BU pre-transplant at different administration levels. The primary objective was to determine the maximum tolerated dose (MTD) of BU that could be safely given over the least number of days. All patients, except one, received maintenance treatment post-transplant, mostly for 2 years. We enrolled 13 patients, mean age of 73 years (range 68–80). Pharmacokinetic analysis showed no greater than 2% accumulation in the 13 patients, confirming a lack of accumulation in the multi-dose regimen. No deaths occurred in the peri-transplant period. Grade 3/4 adverse effects were hematological, no dose-limiting toxicity was observed and MTD was not reached. Three patients developed grade 3 mucositis but none developed veno-occlusive disease. Ten (77%) patients achieved a complete remission (CR) post-transplant with a remarkably long average time to best response of 6.7 months (range: 6–14 m), and two attained a partial response. Median overall survival was 84 months (95% CI, 21–104) and the median progression-free survival was 60 months (95% CI, 9–93). Our results suggest that IV BU could be an alternative conditioning regimen to MEL 140 in elderly patients with MM, and supports future randomized trials

Investigation Into the Reproducibility of the Association of Cord Blood Magnesium Concentration and Cerebral Palsy or Death in Children

Objective: To evaluate the association of cord blood magnesium concentrations at the time of birth with cerebral palsy (CP) and neonatal death. Study Design: A secondary analysis of a randomized controlled trial that randomized women at imminent risk of delivery between 24 and 31 weeks of gestation to receive magnesium sulfate or placebo. This ‘study’s primary outcome was a composite of either moderate to severe CP or death. Secondary outcomes included CP, moderate to severe CP, neonatal death, and neonatal head ultrasound findings. We used a logistic regression model to evaluate the relationship between the concentration of magnesium in cord blood and study outcomes. Results: A total of 668 women were included in this analysis and were randomized to magnesium sulfate at 28 ± 2.5 ‘weeks’ gestation. Cord blood magnesium concentrations were not associated with the primary outcome of infant death by 1 year of age or moderate or severe cerebral palsy, as assessed at or beyond 2 years of age (aOR 0.95 (0.67, 1.36), p = 0.79). Cord blood magnesium concentrations were not associated with any of the secondary outcome measurements. Conclusion: Cord blood magnesium concentrations were not associated with moderate to severe cerebral palsy or death, or other neurodevelopmental or sonographic outcomes

Optimal Dosing of Enoxaparin in Overweight and Obese Children

Aim:Current enoxaparin dosing guidelines in children are based on total bodyweight. This is potentially inappropriate in obese children as it may overestimate thedrug clearance. Current evidence suggests that obese children may require lower ini-tial doses of enoxaparin, therefore the aim of this work was to characterise the phar-macokinetics of enoxaparin in obese children and to propose a more appropriatedosing regimen.Methods:Data from 196 unique encounters of 160 children who received enoxa-parin treatment doses were analysed. Enoxaparin concentration was quantified usingthe chromogenic anti factor Xa (anti-Xa) assay. Patients provided a total of 552 anti-Xa samples. Existing published pharmacokinetic (PK) models were fitted and evalu-ated against our dataset using prediction-corrected visual predictive check plots(pcVPCs). A PK model was fitted using a nonlinear mixed-effects modelling approach.The fitted model was used to evaluate the current standard dosing and identify anoptimal dosing regimen for obese children.Results:Published models of enoxaparin pharmacokinetics in children did not capturethe pharmacokinetics of enoxaparin in obese children as shown by pcVPCs. A one-compartment model with linear elimination best described the pharmacokinetics ofenoxaparin. Allometrically scaled fat-free mass with an estimated exponent of 0.712(CI 0.66-0.76) was the most influential covariate on clearance while linear fat-freemass was selected as the covariate on volume. Simulations from the model showedthat fat-free mass-based dosing could achieve the target anti-Xa activity at steadystate in 77.5% and 78.2% of obese and normal-weight children, respectively, com-pared to 65.2% and 75.5% for standard total body weight-based dosing.Conclusions:A population PK model that describes the time course of anti-Xa activ-ity of enoxaparin was developed in a paediatric population. Based on this model, aunified dosing regimen was proposed that will potentially improve the success rate oftarget attainment in overweight/obese patients without the need for patient bodysize categorisation. Therefore, prospective validation of the proposed approach iswarranted

Dosing Recommendations for Vancomycin in Children and Adolescents with Varying Levels of Obesity and Renal Dysfunction: a Population Pharmacokinetic Study in 1892 Children Aged 1–18 Years

Vancomycin is an effective but potentially nephrotoxic antibiotic commonly used for severe infections. Dosing guidelines for vancomycin in obese children and adolescents with or without renal impairment are currently lacking. This study describes the pharmacokinetics of vancomycin in a large pediatric cohort with varying degrees of obesity and renal function to design practical dosing guidelines for this population. A multi-center retrospective population pharmacokinetic study was conducted using data from patients aged 1−18 years who received \u3e1 dose of vancomycin and had ≥1 vancomycin concentration measured between January 2006 and December 2012. Besides pharmacokinetic data, age, gender, body weight, creatinine clearance (CLcr, bedside Schwartz equation), ward, race, and neutropenic status were collected. Population pharmacokinetic analysis and simulations were performed using NONMEM7.4. A total of 1892 patients (5524 samples) were included, with total body weight (TBW) ranging 6−188 kg (1344 normal weight, 247 overweight, and 301 obese patients) and CLcr down to 8.6 mL/min/1.73 m2. The two-compartment model, with clearance (CL) significantly increasing with TBW and CLcr, central and peripheral volume of distribution and inter-compartmental clearance increasing with TBW, performed well for all age, weight, and renal function ranges. A dosing guideline is proposed that integrates body weight and CLcr resulting in effective and safe exposures across all ages, body weight, and renal functions in the pediatric population. We have characterized the full pharmacokinetic profile of vancomycin in obese children and adolescents aged 1−18 years and propose a practical dosing guideline that integrates both body weight and renal function

Therapeutic Potential of Citrulline as an Arginine Supplement: A Clinical Pharmacology Review

Supplemental arginine has shown promise as a safe therapeutic option to improve endogenous nitric oxide (NO) regulation in cardiovascular diseases associated with endothelial dysfunction. L-arginine, an endogenous amino acid, was reported in clinical studies in adults to improve cardiovascular function in hypertension, pulmonary hypertension, pre-eclampsia, angina, and mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. L-citrulline, a natural precursor of L-arginine, is more bioavailable than L-arginine because of hepatic first-pass metabolism avoidance and longer circulation time. Although not yet well studied, arginine/citrulline has immense therapeutic potential in some life-threatening diseases of children. However, optimal clinical development of arginine or citrulline in children is dependent on more information about pharmacokinetics and exposure-response relationships at appropriate ages and under relevant disease states. This article summarizes the pre-clinical and clinical studies of arginine/citrulline in both adults and children, including currently available pharmacokinetic information. The pharmacology of arginine/citrulline is confounded by several patient-specific factors such as baseline variation of arginine/citrulline due to developmental ages and disease states. Currently available pharmacokinetic studies are not enough to inform the optimal design of clinical studies, especially those in children. Successful bench to bedside clinical translation of arginine supplementation awaits information from well-designed pharmacokinetic-pharmacodynamic studies, along with pharmacometric approaches

Myeloid-Derived Suppressor Cells and Pancreatic Cancer: Implications in Novel Therapeutic Approaches

Pancreatic ductal adenocarcinoma (PDAC) remains a devastating human malignancy with poor prognosis and low survival rates. Several cellular mechanisms have been linked with pancreatic carcinogenesis and also implicated in inducing tumor resistance to known therapeutic regimens. Of various factors, immune evasion mechanisms play critical roles in tumor progression and impeding the efficacy of cancer therapies including PDAC. Among immunosuppressive cell types, myeloid-derived suppressor cells (MDSCs) have been extensively studied and demonstrated to not only support PDAC development but also hamper the anti-tumor immune responses elicited by therapeutic agents. Notably, recent efforts have been directed in devising novel approaches to target MDSCs to limit their effects. Multiple strategies including immune-based approaches have been explored either alone or in combination with therapeutic agents to target MDSCs in preclinical and clinical settings of PDAC. The current review highlights the roles and mechanisms of MDSCs as well as the implications of this immunomodulatory cell type as a potential target to improve the efficacy of therapeutic regimens for PDAC

Antibiotic Treatment of Suspected and Confirmed Neonatal Sepsis Within 28 Days of Birth: A Retrospective Analysis

Neonatal sepsis causes significant mortality and morbidity worldwide. Diagnosis is usually confirmed via blood culture results. Blood culture sepsis confirmation can take days and suffer from contamination and false negatives. Empiric therapy with antibiotics is common. This study aims to retrospectively describe and compare treatments of blood culture-confirmed and unconfirmed, but suspected, sepsis within the University of Utah Hospital system. Electronic health records were obtained from 1,248 neonates from January 1, 2006, to December 31, 2017. Sepsis was categorized into early-onset (≤3 days of birth, EOS) and late-onset (\u3e3 and ≤28 days of birth, LOS) and categorized as culture-confirmed sepsis if a pathogen was cultured from the blood and unconfirmed if all blood cultures were negative with no potentially contaminated blood cultures. Of 1,010 neonates in the EOS cohort, 23 (2.3%) were culture-confirmed, most with Escherichia coli (42%). Treatment for unconfirmed EOS lasted an average of 6.1 days with primarily gentamicin and ampicillin while confirmed patients were treated for an average of 12.3 days with increased administration of cefotaxime. Of 311 neonates in the LOS cohort, 62 (20%) were culture-confirmed, most culturing coagulase negative staphylococci (46%). Treatment courses for unconfirmed LOS lasted an average of 7.8 days while confirmed patients were treated for an average of 11.4 days, these patients were primarily treated with vancomycin and gentamicin. The use of cefotaxime for unconfirmed EOS and LOS increased throughout the study period. Cefotaxime administration was associated with an increase in neonatal mortality, even when potential confounding factors were added to the logistic regression model (adjusted odds ratio 2.8, 95%CI [1.21, 6.88], p = 0.02). These results may not be generalized to all hospitals and the use of cefotaxime may be a surrogate for other factors. Given the low rate of blood culture positive diagnosis and the high exposure rate of empiric antibiotics, this patient population might benefit from improved diagnostics with reevaluation of antibiotic use guideline

Oral Drug Dosing Following Bariatric Surgery: General Concepts and Specific Dosing Advice

Bariatric or weight-loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended-release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case-by-case basis is required for each drug