Pharmacokinetic considerations in obesity

Investigation of real-life drug intake behaviour in older adults and geriatric patients in Northern Germany - A biopharmaceutical perspective

Dosing conditions (type and amount of accompanying fluid, the type of food, the time of administration, and dosage form modifications such as crushing tablets) are critical and affect the performance of oral dosage forms in the gastrointestinal tract and thus bioavailability. Because older adults are the primary users of medications and are more susceptible to adverse effects, it is important to understand how they take their medications in order to reduce risks and increase benefits of the pharmacotherapy. The aim of the study was to investigate the real-life drug intake behaviour in geriatric patients and older adults and discuss their influence on drug absorption after oral administration. The data from two settings home vs. hospital and genders women vs. men were presented. A questionnaire study was performed among people aged at least 65 years from two settings (hospital vs. home), recruited mostly from community pharmacies and a regional hospital in Mecklenburg - Western Pomerania. The obtained data demonstrates that older adults and geriatric patients take their medications in the same way regardless of the setting and gender. There were no significant differences. Interviewed participants were mostly adherent to the doctor's recommendations and mostly took their medications in the same way every day. Medications are most commonly taken with a small (100 mL) or large (200 mL) glass of noncarbonated water, after food (during or after breakfast 64 % of intakes in the morning and during or after dinner 81 % of intakes in the evening). Meal usually consisted of bread, either with jam or honey (breakfast), or ham and cheese (dinner). All reported dosage form modifications were made to tablets. In almost all cases it was splitting the tablet, which was performed due to doctor's indication.

Comparative Efficacy and Safety of Super-Bioavailable Itraconazole-130 mg Once Daily in Obese and Non-Obese Patients of Glabrous Tinea

Background

Obesity is considered one of the risk factors for dermatophytosis and warrants systemic therapy. Itraconazole is the most commonly used antifungal, but owing to pharmacokinetic challenges, super-bioavailable itraconazole (SITZ) was approved globally, recently. For the management of dermatophytosis in obese patients, there are mixed opinions regarding the dosing of systemic antifungals.

Materials and Methods

This study was conducted to compare the efficacy and safety of SITZ-130 mg once daily in glabrous tinea or dermatophytosis in obese and non-obese patients for a total duration of 10 weeks on 87 eligible patients. Efficacy and safety assessments were done at weeks 3 and 6 with follow-up at week 10 for relapse. The primary objective was to assess the proportion of patients achieving complete cure at week 6 with the assessment of safety, clinical, and mycological cure rates as secondary objectives.

Results

Out of 87 patients, 80 were considered for analysis. At week 6, 22/35 (63%) and 33/45 (73%) patients in obese and non-obese groups were completely cured (P = 0.47). Similarly, there was no statistically significant difference for mycological and clinical cure in both the groups (P = 0.17 and P = 0.61, respectively). Four patients in the obese group (18% of completely cured), while one patient in the non-obese group (3% of completely cured), relapsed within 4 weeks of completion of treatment (P = 0.14). The therapy was well tolerated by both groups, with only one patient in the non-obese group experiencing pruritus.

Conclusion

SITZ-130 mg once daily achieved desired and similar clinical response in obese patients as of non-obese patients suffering from dermatophytosis, and hence, a higher dose may not require in obesity.

The Importance of Assessing Drug Pharmacokinetics and Pharmacodynamics in the Obese Population During Drug Development

Obesity remains a US national health crisis and a growing concern worldwide. Concerningly, individuals who are obese are at an increased risk for comorbid diseases that include, but are not limited to, hypertension, diabetes, cardiovascular disease, and cancer. Beyond the risk for developing these conditions, obesity may also impact the pharmacological activity of the therapies being used to treat them and other disease states. The pharmacokinetics (PK), pharmacodynamics (PD), safety, and efficacy of therapies, both currently marketed and under clinical development, may be directly impacted by the physiological alterations that occur secondary to the occurrence of chronic excess body weight. The increased prevalence of this disease should not be ignored. Both private and federal institutions involved in drug research and development should consider, as appropriate, a greater inclusion of individuals who are obese in clinical trials throughout the entirety of drug development, and leverage the available PK, PD, safety, and efficacy data to make more informed dosing recommendations.

Impact of body mass index and its change on survival outcomes in patients with early breast cancer: A pooled analysis of individual-level data from BCIRG-001 and BCIRG-005 trials

INTRODUCTION

The relationships between body mass index (BMI) and survival rates are complex, and have not been thoroughly investigated in breast cancer patients who received adjuvant chemotherapy.

METHODS

We collected data on 2394 patients from two randomized, phase III clinical trials that investigated adjuvant chemotherapy in breast cancer identified in Project Data Sphere. The objective was to examine the effect of baseline BMI, BMI after adjuvant chemotherapy, and BMI change from baseline to post-adjuvant chemotherapy on disease-free survival (DFS) and overall survival (OS). Restricted cubic splines were used to examine potential non-linear associations between continuous BMI value and survival. Stratified analyses involved chemotherapy regimens.

RESULTS

Severe obesity (BMI≥40.0 kg/m2) at baseline was independently associated with worse DFS (hazard ration [HR] = 1.48, 95% confidence interval [CI] 1.02-2.16, P = 0.04) and OS (HR = 1.79, 95%CI 1.17-2.74, P = 0.007) compared with underweight/normal weight (BMI≤24.9 kg/m2). A BMI loss >10% was also an independent prognostic factor for adverse OS (HR = 2.14, 95%CI 1.17-3.93, P = 0.014). Stratified analyses revealed that severe obesity adversely affected DFS (HR = 2.38, 95%CI 1.26-4.34, P = 0.007) and OS (HR = 2.90, 95%CI 1.46-5.76, P = 0.002) in the docetaxel-based group, but not in the non-docetaxel-based group. Restricted cubic splines revealed a "J-shaped" association of baseline BMI with risk of recurrence or all-cause death, and this relationship was more pronounced in the docetaxel-based group.

CONCLUSIONS

In early breast cancer patients treated with adjuvant chemotherapy, baseline severe obesity was significantly linked to worse DFS and OS, and a BMI loss over 10% from baseline to post-adjuvant chemotherapy also negatively affected OS. Moreover, the prognostic role of BMI might differ between docetaxel-based and non-docetaxel-based groups.

Efficacy of Super-Bioavailable Itraconazole and Conventional Itraconazole at Different Dosing Regimens in Glabrous Tinea Infection - A Randomized Clinical Trial

Introduction

Itraconazole follows non-linear pharmacokinetics and hence is recommended once daily, but in real-world practice, is commonly prescribed as twice daily. Hence, this study aimed to evaluate the efficacy and safety of super-bioavailable-itraconazole-130 mg (SB-130) and conventional-itraconazole-200 mg (CITZ-200) once daily compared with conventional-itraconazole-100 mg (CITZ-100) twice daily in glabrous tinea.

Methods

A total of 261 eligible patients were enrolled in this prospective, randomized, clinical study from December-2021 to August-2022 at seven centers in India. Efficacy and safety assessments were done at week-3 and 6, with follow-up at week-10 for relapse. The primary objective was to assess the proportion of patients who achieved complete cure at week-6 following treatment in all itraconazole groups. The secondary outcomes were safety and clinical and mycological cure rates.

Results

Of 261 patients, 240 were included in the analysis. At week-6, 140 patients were completely cured; thus, overall cure rate was 58.33%. Fifty-five patients (69%) in SB-130 while 47/77 (61%) and 38/83 (46%) patients were completely cured in CITZ-200 and CITZ-100 groups respectively (p<0.05; SB-130: CITZ-100, p=0.32; SB-130: CITZ-200, p=0.058; CITZ-200: CITZ-100). There was no statistical difference in the mycological cure rate and area clearance rate between any of the groups (p=0.14); however, a statistically significant difference was noted for OD dosing over BD dosing in achieving clinical cure rates (p<0.05). A total of 13/140 patients (9%) relapsed following complete cure, with no statistically significant difference between any of the groups (p=0.50). All treatments were safe and well-tolerated, with no discontinuation.

Conclusion

In this clinical study, moderate efficacy with all doses of ITZ was reported but was better with OD dosing. Although there was no statistical difference between SB-130 and CITZ-200, SB-130 may be preferred over CITZ-200 owing to the advantage of SB over the conventional ITZ.

The Optimal Dosing Regimen of Super Bioavailable Itraconazole in Obesity: An Experimental Rat Model Study

Background Obesity may alter tissue distribution and clearance of several drugs, especially lipophilic ones. Itraconazole, a lipophilic drug, has been recently introduced in a super-bioavailable formulation (SB-ITZ) for the treatment of dermatophytosis. Evidence regarding optimal dosing of SB-ITZ in obesity is lacking. A current experimental study was planned to analyze tissue concentrations of SB-ITZ at different doses in obese and non-obese rats.  Materials and methods Thirty-six Wistar albino rats of either sex were divided into obese and non-obese rats equally. Further, rats in both categories were divided into three dosing groups. Group 1 received SB-ITZ 13 mg once daily in the morning, group 2 received SB-ITZ 13 mg in the morning and 6.5 mg in the evening, while Group 3 rats received SB-ITZ 13 mg twice daily, orally. Concentrations of SB-ITZ in the skin, serum, and fatty tissue were assessed in each group on days 7, 14, 21, and 28. Comparison of SB-ITZ concentrations in various tissues in obese and non-obese rats and inter-group comparison of tissue concentrations across the three dosing regimens was done at day 28 and expressed as Mean ± SD.36 Wistar rats were divided into obese and non-obese rats equally. Results At day 28, skin concentrations of SB-ITZ were 5.36±1.1, 8.9±1.7 and 10.13±1.7 µg/g in Groups 1, 2, and 3, respectively, in non-obese rats, which was statistically significant (p<0.05) than skin concentration of obese rats (2.72±0.6, 4.2±0.7 and 4.66±0.5 µg/g) for the corresponding dosing groups respectively. Skin concentration of SB-ITZ was statistically significant for Groups 2 and 3 as compared to Group 1. Still, no statistically significant difference was noted between Groups 2 and 3 in non-obese and obese rats. Fatty tissue concentration of SB-ITZ was comparable in all 3 dosing regimens in non-obese and obese rats. But on the intergroup comparison, a statistically significant difference was observed for Groups 2 and 3 against Group 1 (p<0.05). Increasing the dose of SB-ITZ increased serum concentration. In non-obese rats, a statistically significant difference was noted between Group 2 (74.33±6.6 ng/ml) and Group 1 (52.5±9.9 ng/ml); p<0.01 and also in Group 3 (81.33±6.8 ng/ml) against Group 1; p<0.01. Group 3 achieved significantly higher concentration than the other two groups in obese rats (Group 3; 72±5.3, Group 2; 60.5±4.3, and Group 1; 45±7 ng/ml; p<0.01). Conclusion Overall, skin, fatty tissue, and serum concentrations of SB-ITZ were higher in non-obese rats compared to obese rats in all three dosing groups. Moreover, skin and fatty tissue concentrations were proportionately higher than serum in all the groups in non-obese and obese rats. Though the skin concentration of non-obese rats was significantly higher than obese rats, skin concentration in obese rats was within the minimum inhibitory concentration (MIC) range, demonstrating the efficacy of all dosing regimens.

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.

Drug pharmacokinetics in the obese population: challenging common assumptions on predictors of obesity-related parameter changes

INTRODUCTION

Obesity is associated with many physiological changes. We review available evidence regarding five commonly accepted assumptions to a priori predict the impact of obesity on drug pharmacokinetics (PK).

AREAS COVERED

The investigated assumptions are: 1) lean body weight is the preferred descriptor of clearance and dose adjustments; 2) volume of distribution increases for lipophilic, but not for hydrophilic drugs; 3) CYP-3A4 activity is suppressed and UGT activity is increased, implying decreased and increased dose requirements for substrates of these enzyme systems, respectively; 4) glomerular filtration rate is enhanced, necessitating higher doses for drugs cleared through glomerular filtration; 5) drug dosing information from obese adults can be extrapolated to obese adolescents.

EXPERT OPINION

Available literature contradicts, or at least limits the generalizability, of all five assumptions. Clinical studies should focus on quantifying the impact of duration and severity of obesity on drug PK in adults and adolescents, and also include oral bioavailability and pharmacodynamics in these studies. Physiologically-based PK approaches can be used to predict PK changes for individual drugs, but can also be used to define in general terms based on patient characteristics and drug properties, when certain assumptions can or cannot be expected to be systematically accurate.

Predictors for development of oxaliplatin-induced peripheral neuropathy in cancer patients as determined by ordered logistic regression analysis

Background

Oxaliplatin causes acute cold-induced neurotoxicity and chronic cumulative neuropathy, which can require dose modification and impacts quality of life. However, effective strategies for managing oxaliplatin-induced peripheral neuropathy (OIPN) among affected patients remain elusive.

Objective

This retrospective study aimed to identify predictors for the development of OIPN.

Methods

Participants comprised 322 cancer patients at our hospital who were receiving oxaliplatin between January 2017 and March 2021. For the regression analysis of factors associated with OIPN, variables were manually extracted from medical charts. The severity of OIPN was evaluated using the National Cancer Institute’s Common Terminology Criteria for Adverse Events, version 5. Multivariate ordered logistic regression analysis was performed to identify predictors for the development of OIPN. Optimal cut-off thresholds were determined using receiver operating characteristic analysis. Values of P <0.05 (2-tailed) were considered significant.

Results

Significant risk factors identified included higher body mass index (BMI) (odds ratio [OR] = 1.06, 95% confidence interval [CI] = 1.00–1.12; P = 0.043), female sex (OR = 1.67, 95%CI = 1.06–2.61; P = 0.026) and higher total dosage (OR = 2.39, 95%CI = 1.67–3.42; P = < 0.0001).

Conclusion

High BMI, female sex and high total dosage were identified as significant predictors for the development of OIPN.

Dexamethasone exposure in normal-weight and obese hospitalized COVID-19 patients: An observational exploratory trial

During the latest pandemic, the RECOVERY study showed the benefits of dexamethasone (DEX) use in COVID‐19 patients. Obesity has been proven to be an independent risk factor for severe forms of infection, but little information is available in the literature regarding DEX dose adjustment according to body weight. We conducted a prospective, observational, exploratory study at Geneva University Hospitals to assess the impact of weight on DEX pharmacokinetics (PK) in normal‐weight versus obese COVID‐19 hospitalized patients. Two groups of patients were enrolled: normal‐weight and obese (body mass index [BMI] 18.5–25 and >30 kg/m², respectively). All patients received the standard of care therapy of 6 mg DEX orally. Blood samples were collected, and DEX concentrations were measured. The mean DEX AUC_0–8 and C_max were lower in the obese compared to the normal‐weight group (572.02 ± 258.96 vs. 926.92 ± 552.12 ng h/ml and 138.67 ± 68.03 vs. 203.44 ± 126.30 ng/ml, respectively). A decrease in DEX AUC_0–8 of 4% per additional BMI unit was observed, defining a significant relationship between weight and DEX AUC_0–8 (p = 0.004, 95% CI 2–7%). In women, irrespective of the BMI, DEX AUC_0–8 increased by 214% in comparison to men (p < 0.001, 95% CI 154–298%). Similarly, the mean C_max increased by 205% in women (p < 0.001, 95% CI 141–297%). Conversely, no significant difference between the obese and normal‐weight groups was observed for exploratory treatment outcomes, such as the length of hospitalization. BMI, weight, and gender significantly affected DEX AUC. We conclude that dose adjustment would be needed if the aim is to achieve the same exposures in normal‐weight and obese patients.

Characterizing Pharmacokinetics in Children With Obesity-Physiological, Drug, Patient, and Methodological Considerations

Childhood obesity is an alarming public health problem. The pediatric obesity rate has quadrupled in the past 30 years, and currently nearly 20% of United States children and 9% of children worldwide are classified as obese. Drug distribution and elimination processes, which determine drug exposure (and thus dosing), can vary significantly between patients with and without obesity. Obesity-related physiological changes, such as increased tissue volume and perfusion, altered blood protein concentrations, and tissue composition can greatly affect a drug's volume of distribution, which might necessitate adjustment in loading doses. Obesity-related changes in the drug eliminating organs, such as altered enzyme activity in the liver and glomerular filtration rate, can affect the rate of drug elimination, which may warrant an adjustment in the maintenance dosing rate. Although weight-based dosing (i.e., in mg/kg) is commonly practiced in pediatrics, choice of the right body size metric (e.g., total body weight, lean body weight, body surface area, etc.) for dosing children with obesity still remains a question. To address this gap, the interplay between obesity-related physiological changes (e.g., altered organ size, composition, and function), and drug-specific properties (e.g., lipophilicity and elimination pathway) needs to be characterized in a quantitative framework. Additionally, methodological considerations, such as adequate sample size and optimal sampling scheme, should also be considered to ensure accurate and precise top-down covariate selection, particularly when designing opportunistic studies in pediatric drug development. Further factors affecting dosing, including existing dosing recommendations, target therapeutic ranges, dose capping, and formulations constraints, are also important to consider when undergoing dose selection for children with obesity. Opportunities to bridge the dosing knowledge gap in children with obesity include modeling and simulating techniques (i.e., population pharmacokinetic and physiologically-based pharmacokinetic [PBPK] modeling), opportunistic clinical data, and real world data. In this review, key considerations related to physiology, drug parameters, patient factors, and methodology that need to be accounted for while studying the influence of obesity on pharmacokinetics in children are highlighted and discussed. Future studies will need to leverage these modeling opportunities to better describe drug exposure in children with obesity as the childhood obesity epidemic continues.

Differential effect of body mass index (BMI) on outcomes of patients treated with docetaxel in prostate cancer - An exploratory analysis

OBJECTIVE

There are contradictory data on differential effect of docetaxel based on BMI in patients with breast and prostate cancer. We performed an exploratory analysis to determine if the benefit of docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC) is modified by BMI.

METHODS

We performed a post hoc analysis of the data retrieved from the ENTHUSE M1C study. BMI (kg/m²) was categorized as: 18.5 to <25 as lean; 25 to <30 as overweight; and ≥30 as obese. Cox regression models were constructed to determine the impact of BMI on progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 466 patients were eligible for the current analysis. The median PFS was 7.3, 7.7 and 8.4 months (hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.81 to 1.06; P = 0.261) in lean, overweight and obese patients. The median OS was 16.6, 20.1 and 21.4 months (HR, 0.75; 95% CI, 0.63 to 0.89; P = 0.002) for lean, overweight and obese patients. After adjusting for baseline and tumor characteristics, there was no association of BMI with PFS (overweight, HR, 0.89; 95% CI, 0.71 to 1.13; P = 0.353; obese, HR, 0.86; 95% CI, 0.66 to 1.13; P = 0.277) while overweight (HR, 0.68; 95% CI, 0.51 to 0.89; P = 0.006) and obese (HR, 0.59; 95% CI, 0.41 to 0.83; P = 0.003) patients had significantly better OS compared with lean patients.

CONCLUSIONS

There was no effect of BMI on PFS in patients with mCRPC receiving docetaxel. Interestingly, overweight and obese patients had a longer OS compared with lean patients, which is in contradiction to a recent study in breast cancer; and warrants further investigation.

Effect of obesity on gastrointestinal transit, pressure and pH using a wireless motility capsule

BACKGROUND

Despite the increasing prevalence and medical burden of obesity, the understanding of gastrointestinal physiology in obesity is scarce, which hampers drug development.

AIM

To investigate the effect of obesity and food intake on gastrointestinal transit, pressure and pH.

MATERIAL AND METHODS

An exploratory cross-sectional study using a wireless motility capsule (SmartPill©) was performed in 11 participants with obesity and 11 age- and gender-matched participants with normal weight (group) in fasted and fed state (visit). During the first visit, the capsule was ingested after an overnight fast. During a second visit, the capsule was ingested after a nutritional drink to simulate fed state. Linear mixed models were constructed to compare segmental gastrointestinal transit, pressure and pH between groups (obesity or control) and within every group (fasted or fed).

RESULTS

Food intake slowed gastric emptying in both groups (both P < 0.0001), though food-induced gastric contractility was higher in participants with obesity compared to controls (P = 0.02). In the small intestine, a higher contractility (P = 0.001), shorter transit (P = 0.04) and lower median pH (P = 0.002) was observed in participants with obesity compared to controls. No differences were observed for colonic measurements.

CONCLUSION

Obesity has a profound impact on gastrointestinal physiology, which should be taken into account for drug development.

Antineoplastic dosing in overweight and obese cancer patients: an Associazione Italiana Oncologia Medica (AIOM)/Associazione Medici Diabetologi (AMD)/Società Italiana Endocrinologia (SIE)/Società Italiana Farmacologia (SIF) multidisciplinary consensus position paper

Most anticancer molecules are administered in body-size-based dosing schedules, bringing up unsolved issues regarding pharmacokinetic data in heavy patients. The worldwide spread of obesity has not been matched by improved methods and strategies for tailored drug dosage in this population. The weight or body surface area (BSA)-based approaches may fail to fully reflect the complexity of the anthropometric features besides obesity in cancer patients suffering from sarcopenia. Likewise, there is a lack of pharmacokinetic data on obese patients for the majority of chemotherapeutic agents as well as for new target drugs and immunotherapy. Therefore, although the available findings point to the role of dose intensity in cancer treatment, and support full weight-based dosing, empirical dose capping often occurs in clinical practice in order to avoid toxicity. Thus a panel of experts of the Associazione Italiana Oncologia Medica (AIOM), Associazione Medici Diabetologi (AMD), Società Italiana Endocrinologia (SIE), and Società Italiana Farmacologia (SIF), provides here a consensus statement for appropriate cytotoxic chemotherapy and new biological cancer drug dosing in obese patients.

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The worldwide spread of obesity is an emerging challenge also in cancer patients

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Weight or BSA-based approaches do not adequately address the critical issue of optimal dosing for cancer drugs under obesity

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Empirical dose capping is often employed in clinical practice to avoid toxicities among overweight and obese patients

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There is a lack of clinical and pharmacokinetic studies in this population

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Clinical practice recommendations should guide suitable dosing of cytotoxic and biological cancer drugs in obese patients

Crown-Like Structures in Breast Adipose Tissue: Early Evidence and Current Issues in Breast Cancer

Obesity is an established risk factor for postmenopausal breast cancer and has been linked to worse breast cancer prognosis, most clearly for hormone receptor-positive breast cancers. The underlying mechanisms of the obesity-breast cancer association are not fully understood, but growing evidence points to the breast adipose tissue microenvironment playing an important role. Obesity-induced adipose tissue dysfunction can result in a chronic state of low-grade inflammation. Crown-like structures of the breast (CLS-B) were recently identified as a histologic marker of local inflammation. In this review, we evaluate the early evidence of CLS-B in breast cancer. Data from preclinical and clinical studies show that these inflammatory lesions within the breast are associated with local NF-κB activation, increased aromatase activity, and elevation of pro-inflammatory mediators (TNFα, IL-1β, IL-6, and COX-2-derived PGE2)-factors involved in multiple pathways of breast cancer development and progression. There is also substantial evidence from epidemiologic studies that CLS-B are associated with greater adiposity among breast cancer patients. However, there is insufficient evidence that CLS-B impact breast cancer risk or prognosis. Comparisons across studies of prognosis were complicated by differences in CLS-B evaluation and deficiencies in study design, which future studies should take into consideration. Breast adipose tissue inflammation provides a plausible explanation for the obesity-breast cancer association, but further study is needed to establish its role and whether markers such as CLS-B are clinically useful.

The Role of Obesity in the Development and Management of Gynecologic Cancer

Importance

Endometrial cancer is the most common gynecologic malignancy, with an estimated 54,000 new cases and 10,000 deaths in the United States in 2015. The obesity epidemic directly contributes to the escalating prevalence of chronic diseases, including obesity-related cancers. Patient body weight and nutritional status markedly impact perioperative oncologic care, chemotherapy administration, recurrence risk, and survivorship goals.

Objectives

The objective of this review is to explore the association between obesity and the development, treatment, and survival outcomes of gynecologic cancers.

Evidence Acquisition

A systematic literature review was performed utilizing PubMed and ClinicalTrials.gov.

Conclusions and Relevance

Caring for obese women with gynecologic cancers presents unique challenges. A coordinated multidisciplinary and system effort is required to address the prevention and treatment of obesity, as the sequela of this disease is a clear risk factor for the development of gynecologic malignancy and other comorbidities. Health care providers must be ready to address this worldwide health problem.

The Crashing Obese Patient

The obesity pandemic now affects hundreds of millions of people worldwide. As obesity rates continue to increase, emergency physicians are called on with increasing frequency to resuscitate obese patients. This article discusses important anatomic, physiologic, and practical challenges imposed by obesity on resuscitative care. Impacts on hemodynamic monitoring, airway and ventilator management, and pharmacologic therapy are discussed. Finally, several important clinical scenarios (trauma, cardiac arrest, and sepsis), in which alterations to standard treatments may benefit obese patients, are highlighted.

Differential Benefit of Adjuvant Docetaxel-Based Chemotherapy in Patients With Early Breast Cancer According to Baseline Body Mass Index

PURPOSE

Lipophilic drugs, such as taxanes, have a high affinity for adipose tissue and a resulting higher volume of distribution. Here, we reanalyzed clinical trial data to investigate whether the efficacy of docetaxel-based chemotherapy differs from non-docetaxel-based chemotherapy in patients with breast cancer according to their baseline body mass index (BMI).

PATIENTS AND METHODS

We retrospectively analyzed data from all of the patients in the adjuvant BIG 2-98 trial (ClinicalTrials.gov identifier: NCT00174655; N = 2,887) comparing non-docetaxel- to docetaxel-containing chemotherapy. BMI (kg/m²) was categorized as follows: 18.5 to < 25, lean; 25 to < 30, overweight; and ≥ 30, obese. Disease-free survival (DFS) was the primary endpoint, and overall survival (OS) was the secondary endpoint. A second-order interaction was assessed among treatment, BMI, and estrogen receptor (ER) status.

RESULTS

There was no difference in DFS or OS according to BMI in the non-docetaxel group, while reduced DFS and OS were observed with increasing BMI category in the docetaxel group. Adjusted hazard ratios for DFS and OS were, respectively, 1.12 (95% CI, 0.98 to 1.50; P = .21) and 1.27 (95% CI, 1.01 to 1.60; P = .04) for overweight versus lean groups and were 1.32 (95% CI, 1.08 to 1.62; P = .007) and 1.63 (95% CI, 1.27 to 2.09; P < .001), respectively, for obese versus lean groups. Similar results were obtained when considering ER-negative and ER-positive tumors separately and when considering only patients who received a relative dose intensity ≥ 85% for docetaxel. A joint modifying role of BMI and ER status on treatment effect was evident for DFS (adjusted P = .06) and OS (adjusted P = .04).

CONCLUSION

This retrospective analysis of a large adjuvant trial highlights a differential response to docetaxel according to BMI, which calls for a body composition-based re-evaluation of the risk-benefit ratio of the use of taxanes in breast cancer. These results now must be confirmed in additional series.

Review of nutritional status, body composition, and effects of antineoplastic drug disposition

The overall survival for children with cancer in high income countries is excellent. However, there are many disparities that may negatively affect survival, which are particularly problematic in low income countries, such as nutritional status at diagnosis and throughout therapy. Nutritional status as well as concomitant foods, supplements, and medications may play a role in overall exposure and response to chemotherapy. Emerging science around the microbiome may also play a role and should be further explored as a contributor to disease progression and therapeutic response. This article highlights some of these issues and proposes additional areas of research relevant to nutritional status and pharmacology that are needed in pediatric oncology.

Effect of Body Mass Index on Postoperative Nausea and Vomiting: Propensity Analysis

The impact of body mass index (BMI) on postoperative nausea and vomiting (PONV) is controversial, and few studies have focused on their relationship. We investigated the effects of BMI on PONV, taking into account other PONV risk factors. We analyzed adults over the age of 18 years who received general anesthesia between 2015 and 2019, using propensity score matching. Before propensity score matching, odds ratios (ORs) for PONV were lower for overweight (OR, 0.91; 95% confidence interval (CI), 0.87–0.96; p < 0.0001) or obese patients (OR, 0.77; 95% CI, 0.71–0.84; p < 0.0001) than for normal-BMI patients. After matching, the ORs for PONV of overweight (OR, 0.89; 95% CI, 0.80–0.98; p = 0.016) and obese patients (OR, 0.71; 95% CI, 0.63–0.79; p < 0.0001) were low. However, the ORs of underweight patients did not differ from those of normal-BMI patients, irrespective of matching. Therefore, the incidence of PONV may be lower among adults with a higher-than-normal BMI.

Evaluating Lean Liver Volume as a Potential Scaler for In Vitro-In Vivo Extrapolation of Drug Clearance in Obesity Using the Model Drug Antipyrine

BACKGROUND

In vitro-in vivo extrapolation (IVIVE) of hepatic drug clearance (CL) involves the scaling of hepatic intrinsic clearance (CL_int,uH) by functional liver size, which is approximated by total liver volume (LV) as per the convention. However, in most overweight and obese patients, LV includes abnormal liver fat, which is not thought to contribute to drug elimination, thus overestimating drug CL. Therefore, lean liver volume (LLV) might be a more appropriate scaler of CL_int,uH.

OBJECTIVE

The objective of this work was to assess the application of LLV in CL extrapolation in overweight and obese patients (BMI >25 kg/m2) using a model drug antipyrine.

METHODS

Recently, a model to predict LLV from patient sex, weight, and height was developed and evaluated. In order to assess the LLV model's use in IVIVE, a correlation-based analysis was conducted using antipyrine as an example drug.

RESULTS

In the overweight group (BMI >25 kg/m2), LLV could describe 36% of the variation in antipyrine CL (R² = 0.36), which was >2-fold higher than that was explained by LV (R² = 0.17). In the normal-weight group (BMI ≤25 kg/m2), the coefficients of determination were 58% (R² = 0.58) and 43% (R²= 0.43) for LLV and LV, respectively.

CONCLUSION

The analysis indicates that LLV is potentially a more appropriate descriptor of functional liver size than LV, particularly in overweight individuals. Therefore, LLV has a potential application in IVIVE of CL in obesity.

The Effect of Bariatric Surgery on Oral Antibiotic Absorption: a Systematic Review

PURPOSE

The purpose of this study was to conduct a systematic review of the existing literature to determine the effect of bariatric surgery on various pharmacokinetic parameters of oral antibiotic absorption as well as overall patient outcomes.

MATERIALS AND METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to February 2020. Outcomes of interest included change in pharmacokinetic parameters of oral antibiotics administered to patients following bariatric surgery, using variables such as maximum plasma concentration (Cmax), time to reach maximum plasma concentration (Tmax), area under the concentration-time curve (AUC), clearance, and volume of distribution. MINORS and Cochrane risk of bias tools were used to assess quality of evidence.

RESULTS

Ten studies with 100 patients assessing 8 oral antibiotics were included. The majority (77%) of patients underwent Roux-en-Y gastric bypass (RYGB), with fewer undergoing ventral banded gastroplasty (VBG) (14%), jejunoileostomy (6%), and jejunoileal bypass (3%). Antibiotic classes investigated included beta-lactams (5 studies), fluoroquinolones (2 studies), macrolides (2 studies), and oxazolidinones (1 study). Heterogeneity between studies precluded meaningful pooling or meta-analysis of data. Overall risk of bias was fair.

CONCLUSION

Patients given oral beta-lactams and macrolides warrant close monitoring due to unpredictable absorption post-bariatric surgery, whereas oral fluoroquinolones and linezolid may not be affected. Several studies also showed decreased absorption following RYGB, as well as lower serum exposure in patients with obesity compared to non-obese controls. Clinicians should monitor patients on a case-by-case basis for signs of antibiotic failure or toxicity and reassess dosing accordingly.

Influence of Diet-Induced Obesity on the Bioavailability and Metabolism of Raspberry Ketone (4-(4-Hydroxyphenyl)-2-Butanone) in Mice

OBJECTIVES

Raspberry ketone (RK) is the primary aroma compound in red raspberries and a dietary supplement for weight loss. This work aims to 1) compare RK bioavailability in male versus female, normal-weight versus obese mice; 2) characterize RK metabolic pathways.

METHODS

Study 1: C57BL/6J male and female mice fed a low-fat diet (LFD; 10% fat) receive a single oral gavage dose of RK (200 mg kg-1 ). Blood, brain, and white adipose tissue (WAT) are collected over 12 h. Study 2: Male mice are fed a LFD or high-fat diet (45% fat) for 8 weeks before RK dosing. Samples collected are analyzed by UPLC-MS/MS for RK and its metabolites.

RESULTS

RK is rapidly absorbed (Tmax  ≈ 15 min), and bioconverted into diverse metabolites in mice. Total bioavailability (AUC0-12 h ) is slightly lower in females than males (566 vs 675 nmol mL-1 min-1 ). Total bioavailability in obese mice is almost doubled that of control mice (1197 vs 679 nmol mL-1 min-1 ), while peaking times and elimination half-lives are delayed. Higher levels of RK and major metabolites are found in WAT of the obese than normal-weight animals.

CONCLUSIONS

RK is highly bioavailable, rapidly metabolized, and exhibits significantly different pharmacokinetic behaviors between obese and control mice. Lipid-rich tissues, especially WAT, can be a direct target of RK.

Modelling pharmacokinetics and pharmacodynamics of the selective S1P1 receptor modulator cenerimod in healthy subjects and systemic lupus erythematosus patients

AIMS

Assessment of time to attain steady state as well as drug accumulation following long-term treatment with the selective sphingosine-1-phosphate 1 receptor modulator cenerimod and prediction of the incidence of low total lymphocyte (LY) counts. Differences in pharmacokinetics and pharmacodynamics based on demographic characteristics and between healthy subjects and systemic lupus erythematosus (SLE) patients were to be identified.

METHODS

Data from 4 Phase I studies and 1 Phase II study were pooled to develop a population pharmacokinetic/pharmacodynamic model describing cenerimod concentration and its effect on LY count. Simulations addressed the objectives.

RESULTS

Simulations of 365 days of treatment indicated a time to steady state of 49 days and changes in exposure of 15% beyond 35 days. For a dose of 2 mg, the predicted incidences of LY counts below 0.5 and 0.2 × 10⁹ cells/L were 18.2 and 0.6% for healthy subjects and 25.9 and 1.0% for SLE patients, respectively. Incidence increased with higher dose and lower baseline LY counts. For body weights of 50 and 100 kg compared to 75 kg, exposure was predicted to change by +37% and -20%, respectively.

CONCLUSION

Long-term cenerimod administration is not expected to result in exposure and LY count reduction substantially different from results of completed studies. Low LY counts are predicted to occur more frequently in SLE patients compared to healthy subjects. Dose individualization based on the model is not considered necessary. Model-based simulations enable benefit-risk evaluations, supporting planning of late-phase clinical studies and scientific exchange with health authorities.

Modern pharmacological treatment of obese patients

There are many angles to consider in drug treatment of obese patients. On the one hand, some specific weight loss drugs are available, on the other, several drugs are associated with unintentional weight changes. When treating an obese patient for any given disease, several physiological changes may influence the pharmacokinetic properties of the drugs required. Thus, increased body weight may influence the efficacy and safety of some drug treatments. Even more complicated is the situation after weight reduction surgery. Due to the various changes to the gastrointestinal tract induced by the different surgical techniques used, and the dynamic changes in body composition thereafter, drug dosing has to be constantly reconsidered. Whereas all of these issues are of clinical importance, none of them have been investigated in the necessary depth and broadness to ensure safe and efficacious drug treatment of the massively obese patient. Individual considerations have to be based on comorbidities, concomitant medication, and on specific drug properties, for example, lipophilicity, volume of distribution, and metabolism. In this article we summarize the data available on different aspects of drug treatment in the obese patient with the hope of improving patient care.

Everolimus Exposure and Early Metabolic Response as Predictors of Treatment Outcomes in Breast Cancer Patients Treated with Everolimus and Exemestane

BACKGROUND

Treating breast cancer patients with everolimus and exemestane can be challenging due to toxicity and suboptimal treatment responses.

OBJECTIVE

We investigated whether everolimus exposure and early metabolic response are predictors for toxicity and effectiveness in these patients.

PATIENTS AND METHODS

We performed pharmacokinetic assessments 14 and 35 days after starting treatment. [¹⁸F]fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG-PET) was performed at baseline, and 14 and 35 days after the start of the therapy. We recorded toxicity, defined as dose interventions within 3 months, and progression-free survival (PFS).

RESULTS

Among 44 evaluable patients, the geometric mean (GM) C_trough was higher in patients with toxicity compared to patients without (17.4 versus 12.3 μg/L (p = 0.02)). The optimal cut-off value to predict toxicity was C_trough > 19.2 μg/L. GM C_trough of patients with and without progressive disease (PD) within 3 months was not significantly different (12.0 versus 15.2 μg/L (p = 0.118)). In 28 evaluable patients, PD within 3 months could best be predicted using the percentage decrease in peak standardized uptake value normalized by lean body mass of the lesion with highest FDG uptake (SUL_{peak high}) at day 14. Patients with <11% versus >11% decrease in SUL_{peak high} at day 14 had a median PFS of 90 days versus 411 days, respectively (p = 0.0013) and more frequently had PD within 3 months: 70 vs 11%, respectively.

CONCLUSIONS

Our results show that everolimus toxicity is related to everolimus C_trough. No relation was observed between everolimus exposure and treatment effectiveness. An early FDG-PET can identify patients at high risk of nonresponse. These results warrant further validation. Clinicaltrials.gov identifier: NCT01948960.

Pancreatic Cancer and Obesity: Molecular Mechanisms of Cell Transformation and Chemoresistance

Cancer and obesity are the two major epidemics of the 21st century. Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of death, with a five-year overall survival rate of only 8%. Its incidence and mortality have increased in recent years, and this cancer type is expected to be among the top five leading causes of cancer-related death by 2030 in the United States (US). In the last three decades, the prevalence of overweight people has boosted with a consequent increase in obesity-related diseases. Considerable epidemiologic evidence correlates overweight and obese conditions to an increased risk of several types of cancer, including PDAC. Besides being a risk factor for multiple metabolic disorders, the tumor-promoting effects of obesity occur at the local level via inflammatory mediators that are associated with adipose inflammation and metabolic or hormones mediators and microbiota dysbiosis. Although an excess of body mass index (BMI) represents the second most modifiable risk factor for PDAC with an increased cancer related-death of more than 20–40%, still little is known about the molecular mechanisms that underlie this strong association. In this review, we focused on the role of obesity as a preventable risk factor of PDAC, discussing the molecular mechanisms linking obesity to cancer initiation and progression. Moreover, we highlighted the role of obesity in defining chemoresistance, showing how a high BMI can actually reduce response to chemotherapy.

NHL in adolescents and young adults: A unique population

Non-Hodgkin lymphoma (NHL) is a heterogeneous group of lymphoid malignancies with high incidence in adolescents and young adults (AYAs). The most common diseases include diffuse large B-cell lymphoma, anaplastic large cell lymphoma, Burkitt lymphoma, lymphoblastic lymphoma, and primary mediastinal large B-cell lymphoma. In comparison to younger children and adults, AYAs (15-39 years) with NHL present a specific set of challenges including variations in tumor biology, inconsistent treatment, pharmacodynamics, and psychosocial barriers. While survival of AYAs with NHL has improved, cure rates remain suboptimal. Incorporation of novel agents into pediatric-inspired treatment regimens specifically designed for NHL in AYAs has led to improved outcomes. Consideration of AYAs as a distinct population in the diagnosis and treatment of NHL is encouraged.

Obesity and Pediatric Drug Development

There is a lack of dosing guidelines for use in obese children. Moreover, the impact of obesity on drug safety and clinical outcomes is poorly defined. The paucity of information needed for the safe and effective use of drugs in obese patients remains a problem, even after drug approval. To assess the current incorporation of obesity as a covariate in pediatric drug development, the pediatric medical and clinical pharmacology reviews under the Food and Drug Administration (FDA) Amendments Act of 2007 and the FDA Safety and Innovation Act (FDASIA) of 2012 were reviewed for obesity studies. FDA labels were also reviewed for statements addressing obesity in pediatric patients. Forty-five drugs studied in pediatric patients under the FDA Amendments Act were found to have statements and key words in the medical and clinical pharmacology reviews and labels related to obesity. Forty-four products were identified similarly with pediatric studies under FDASIA. Of the 89 product labels identified, none provided dosing information related to obesity. The effect of body mass index on drug pharmacokinetics was mentioned in only 4 labels. We conclude that there is little information presently available to provide guidance related to dosing in obese pediatric patients. Moving forward, regulators, clinicians, and the pharmaceutical industry should consider situations in drug development in which the inclusion of obese patients in pediatric trials is necessary to facilitate the safe and effective use of new drug products in the obese pediatric population.

Perioperative Care of the Obese Cardiac Surgical Patient

Morbid obesity is associated with impairment of cardiovascular, pulmonary, gastrointestinal, and renal physiology with significant perioperative consequences and has been linked with higher morbidity and mortality after cardiac surgery. Cardiac surgery patients have a higher incidence of difficult airway and difficult laryngoscopy than general surgery patients do, and obesity is associated with difficult mask ventilation and direct laryngoscopy. Positioning injuries occur more frequently because obese patients are at greater risk of pressure injury, such as rhabdomyolysis and compartment syndrome. Despite the association between obesity and several chronic disease states, the effects of obesity on perioperative outcomes are conflicting. Studies examining outcomes of overweight and obese patients in cardiac surgery have reported varying results. An "obesity paradox" has been described, in which the mortality for overweight and obese patients is lower compared with patients of normal weight. This review describes the physiologic abnormalities and clinical implications of obesity in cardiac surgery and summarizes recommendations for anesthesiologists to optimize perioperative care of the obese cardiac surgical patient.

Drug Dosing in Obese Children: Challenges and Evidence-Based Strategies

With the alarming increase of obesity in children, pediatricians are increasingly being confronted with difficult dosing decisions. Many drug labels do not provide specific dosing instructions for children who are obese. In this article, we describe the physiologic parameters altered by obesity and their influences on drug disposition and effect. We review the principles of allometry, and the key pharmacokinetic parameters that can be used to derive age appropriate dosing regimens. Last, we illustrate how appropriate weight descriptors can be selected, and how important PK parameters can be extrapolated for dosing in obese children when pediatric pharmacokinetic information is available.

Antithrombotic therapy in obesity

Clinical management of obese subjects to reduce their risk of suffering cardiovascular events is complex. Obese patients typically require preventive strategies, life-style modifications, and multi-drug therapy to address obesity-induced co-morbidities. Data regarding the effects of excess weight on the pharmacokinetics of most drugs is scarce as these individuals are often excluded from clinical trials. However, the physiological alterations observed in obese patients and their lower response to some antiplatelet agents and anticoagulants have suggested that dosage regimes need to be adjusted for these subjects. In this review we will briefly discuss platelet alterations that can contributeto increased thrombotic risk, analyse existing data regarding the effects of obesity on drug pharmacokinetics focusing on antiplatelet agents and anticoagulants, and we will describe the beneficial effects of weight loss on thrombosis.

Treating tuberculosis with high doses of anti-TB drugs: mechanisms and outcomes

Tuberculosis (TB) is considered as one of the most serious threats to public health in many parts of the world. The threat is even more severe in the developing countries where there is a lack of advanced medical amenities and contemporary anti-TB drugs. In such situations, dosage optimization of existing medication regimens seems to be the only viable option. Therapeutic drug monitoring study results suggest that high-dose treatment regimens can compensate the low serum concentration of anti-TB drugs and shorten the therapy duration. The article presents a critical review on the possible changes that occur in the host and the pathogen upon the administration of standard and high-dose regimens. Some of the most common factors that are responsible for low anti-TB drug concentrations in the serum are differences in hosts' body weight, metabolic processing of the drug, malabsorption and/or drug-drug interaction. Furthermore, failure to reach the cavitary pulmonary and extrapulmonary tissues also contributes to the therapeutic inefficiency of the drugs. In such conditions, administration of higher doses can help in compensating the pathogenic outcomes of enhancement of the pathogen's physical barriers, efflux pumps and genetic mutations. The present article also presents a summary of the recorded treatment outcomes of clinical trials that were conducted to test the efficacy of administration of high dose of anti-tuberculosis drugs. This review will help physicians across the globe to understand the underlying pathophysiological changes (including side effects) that dictate the clinical outcomes in patients administered with standard and/or high dose anti-TB drugs.

Effects of Obesity and Leptin Deficiency on Morphine Pharmacokinetics in a Mouse Model

BACKGROUND

Obesity causes multiorgan dysfunction, specifically metabolic abnormalities in the liver. Obese patients are opioid-sensitive and have high rates of respiratory complications after surgery. Obesity also has been shown to cause resistance to leptin, an adipose-derived hormone that is key in regulating hunger, metabolism, and respiratory stimulation. We hypothesized that obesity and leptin deficiency impair opioid pharmacokinetics (PK) independently of one another.

METHODS

Morphine PK were characterized in C57BL/6J wild-type (WT), diet-induced obese (DIO), and leptin-deficient (ob/ob) mice, and in ob/ob mice given leptin-replacement (LR) therapy. WT mice received several dosing regimens of morphine. Obese mice (30 g) received one 80 mg/kg bolus of morphine. Blood was collected at fixed times after morphine injection for quantification of plasma morphine and morphine 3-glucuronide (M3G) levels. PK parameters used to evaluate morphine metabolism included area-under the curve (AUC150), maximal morphine concentration (CMAX), and M3G-to-morphine ratio, and drug elimination was determined by clearance (Cl/F), volume of distribution, and half-life (T1/2). PK parameters were compared between mouse groups by the use of 1-way analysis of variance, with P values less than .05 considered significant.

RESULTS

DIO compared with WT mice had significantly decreased morphine metabolism with lower M3G-to-morphine ratio (mean difference [MD]: -4.9; 95% confidence interval [CI]: -8.8 to -0.9) as well as a decreased Cl/F (MD: -4.0; 95% CI: -8.9 to -0.03) Ob/ob compared with WT mice had a large increase in morphine exposure with a greater AUC150 (MD: 980.4; 95% CI: 630.1-1330.6), CMAX (MD: 6.8; 95% CI: 2.7-10.9), and longer T1/2 (MD: 23.1; 95% CI: 10.5-35.6), as well as a decreased Cl/F (MD: -7.0; 95% CI: -11.6 to -2.7). Several PK parameters were significantly greater in ob/ob compared with DIO mice, including AUC150 (MD: 636.4; 95% CI: 207.4-1065.4), CMAX (MD: 5.3; 95% CI: 3.2-10.3), and T1/2 (MD: 18.3; 95% CI: 2.8-33.7). When leptin was replaced in ob/ob mice, PK parameters began to approach DIO and WT levels. LR compared with ob/ob mice had significant decreases in AUC150 (MD: -779.9; 95% CI: -1229.8 to -330), CMAX (MD: -6.1; 95% CI: -11.4 to -0.9), and T1/2 (MD: -19; 95% CI: -35.1 to -2.8). Metabolism increased with LR, with LR mice having a greater M3G-to-morphine ratio compared with DIO (MD: 5.3; 95% CI: 0.3-10.4).

CONCLUSIONS

Systemic effects associated with obesity decrease morphine metabolism and excretion. A previous study from our laboratory demonstrated that obesity and leptin deficiency decrease the sensitivity of central respiratory control centers to carbon dioxide. Obesity and leptin deficiency substantially decreased morphine metabolism and clearance, and replacing leptin attenuated the PK changes associated with leptin deficiency, suggesting leptin has a direct role in morphine metabolism.

Hepatotoxicity in Obese Versus Nonobese Patients With Acetaminophen Poisoning Who Are Treated With Intravenous N-Acetylcysteine

There is limited information regarding the outcomes associated with acetaminophen (APAP) poisoning in obese individuals. It is possible that patients who are obese are more susceptible to APAP-induced liver injury, thereby diminishing the efficacy of antidotes such as N-acetylcysteine (NAC). We evaluated the outcomes associated with APAP poisoning in obese versus nonobese adults who are treated with intravenous (IV) NAC. This was a retrospective cohort study conducted in a tertiary care, academic medical center. Adult patients with APAP toxicity, who were treated with IV NAC between June 2005 and August 2012, were included. The patients were categorized into 2 groups based on their body mass index (BMI): (1) obese (BMI ≥ 30.0 kg/m) versus (2) nonobese (BMI 18.5-24.9 kg/m). The primary outcome measure was the proportion of patients who developed hepatotoxicity (aspartate aminotransferase or alanine aminotransferase >1000 IU/L). A total of 80 patients were included in the final cohort (40 in each group). The median BMI for the obese and nonobese groups was 34.5 kg/m [interquartile range (IQR) 31.4-40.2] and 22.4 kg/m (IQR 21.2-23.9), respectively (P < 0.001). Other than more white patients being present in the nonobese group, there were no other baseline differences between groups with regard to demographics, liver function tests, or coagulation studies. Obese patients received a median IV NAC dose of 291.5 mg/kg (IQR 270.8-300.7) compared with 300 mg/kg (IQR 287.8-301.9) in the nonobese group (P = 0.07). Hepatotoxicity occurred in 27.5% of the obese patients and 37.5% of the nonobese patients (P = 0.34). No adverse drug effects were noted in either group. Obese and nonobese patients being treated with IV NAC for APAP toxicity experienced similar rates of hepatotoxicity.

A Multidisciplinary Review of Nutrition Considerations in the Pediatric Oncology Population: A Perspective From Children's Oncology Group

Over the past few decades, great progress has been made in the survival rates of childhood cancer. As survival rates have improved, there has been an increased focus on supportive care. Nutrition is a supportive-care modality that has been associated with improved tolerance to chemotherapy, improved survival, increased quality of life, and decreased risk of infection in children undergoing anticancer therapy. Guidelines and assessment criteria have been proposed for the nutrition management of a child with cancer; however, there is no consistent use of criteria among institutions treating children with cancer. This review will present the current evidence and standards of practice incorporating aspects of nutrition, nursing, pharmacology, and psychosocial challenges to consider in the nutrition management of a child with cancer. Recommendations for clinical practice are presented.

Sedation for Bronchoscopy and Complications in Obese Patients

BACKGROUND

Bronchoscopy is a safe and minimally invasive diagnostic tool, but no studies have reported prospectively on sedation and outcomes in patients with objectively defined obesity.

OBJECTIVES

The purpose of the study is to determine if obese patients require more sedation or had more procedural complications during bronchoscopy under moderate sedation than non-obese patients.

METHODS

We evaluated complications and sedation requirements in non-obese versus obese patients, defined by multiple criteria including body mass index (BMI), neck circumference, abdominal height, and Mallampati scores.

RESULTS

Data were collected prospectively in 258 patients undergoing bronchoscopy under moderate sedation. By varying criteria, there were the following proportions of obese patients: 30% by BMI >30, 39% by neck circumference >40 cm, and 35% by abdominal height >22 cm in males and >20 cm in females. Sedative and analgesic dosing was not clinically significantly higher in obese patients than in non-obese patients. There was no difference in complications or procedural success based on obesity criteria. Hemoglobin oxygen desaturations occurred more often during bronchoscopy in patients with increasing Mallampati scores (p = 0.04), but this had no effect on bronchoscopy time or successful completion of the procedure. A subset of patients with previous polysomnogram-proven obstructive sleep apnea were more likely to have earlier termination of their procedure (15.8%) than patients with no diagnosed sleep apnea (2.3%; p = 0.002).

CONCLUSION

In this prospective assessment of patients with obesity, we found neither clinically significant differences in sedation needs nor increases in complications in obese versus non-obese patients using a variety of indices of obesity.

Outcome of Morbid Obesity in the Intensive Care Unit

This was a retrospective chart review of consecutive obese patients admitted to the medical intensive care unit. Patients were divided into 2 groups: mild to moderately obese (group 1, body mass index =30-40 kg/m2) and morbidly obese (group 2, body mass index >40 kg/m2). Acute Physiology and Chronic Health Evaluation II scores were not significantly different between the 2 groups. Morbidly obese patients (group 2) had higher rates of mortality and nursing home admission. They also showed higher rates of intensive care unit complications including sepsis, nosocomial pneumonia, acute respiratory distress syndrome, catheter infection, tracheostomy, and acute renal failure. Their median length of mechanical ventilation was longer (2 days, range 2-12 vs 9 days, range 1-37, P = .009). In a logistic regression analysis, morbid obesity remained a significant predictor of death or disposition to nursing home even after controlling for age ( P = .019, odds ratio = 7.60, 95% confidence interval = 1.39-41.6). Morbidly obese patients (body mass index >40 kg/m2) admitted to intensive care units have higher rates of mortality, nursing home admission, and intensive care unit complications and have longer stays in the intensive care unit and time on mechanical ventilation.

Pharmacokinetic Alterations of Antimicrobials in the Critically Ill

Critical illness is accompanied by multiple physiologic alterations that affect the pharmacokinetics of antimicrobials. Although the pharmacokinetics of a number of antimicrobials have been studied in critically ill individuals, an understanding of the physiological alterations in critical illness and general pharmacokinetic principles of antimicrobials is imperative for appropriate selection, dosing, and prediction of toxicity.

Hematological toxicity of carboplatin for gynecological cancer according to body mass index

PURPOSE

The aim of the present study was to analyze how patient weight affects the hematological toxicity of carboplatin and whether this toxicity is more prevalent in overweight patients.

METHODS

We performed a retrospective 2-year study of patients diagnosed with a gynecological cancer and whose treatment regimen contained carboplatin (AUC dose = 5 or 6) and paclitaxel (dose = 175 mg/m(2)) every 3 weeks (CP scheme). We recorded all severe hematological events (thrombocytopenia, neutropenia, and/or anemia grade III/IV) according to the CTCAE v4.03, as well as treatment modifications and the need for granulocyte colony-stimulating factors (G-CSF) and/or erythropoietin (EPO) or packed red blood cells (PRBC). Patients with a body mass index (BMI) ≥27 kg/m(2) were considered as overweight (OW) and those with a BMI <27 kg/m(2) were considered as normal weight (NW).

RESULTS

Fifty-two patients met the inclusion criteria (21 patients in the OW group, 31 patients in the NW group). The OW group showed a higher incidence of thrombocytopenia (95% confidence intervals (CI) 1.51-27.72; p < 0.02) and anemia (95% CI 1.06-33.63; p < 0.05). Moreover, this was reflected in a greater number of changes in the usual CP regimen (95% CI 2.19-44.32; p < 0.01). The need for G-CSF and/or EPO/PRBC was also significantly higher in the OW group (95% CI 1.08-12.16; p < 0.04).

CONCLUSIONS

Carboplatin dosing based on real weight in obese patients resulted in increased hematologic toxicity, mainly thrombocytopenia. Dose adjustment based on other descriptors of weight, such as adjusted weight, may be better tolerated by patients. However, future studies are needed to demonstrate not only better safety of carboplatin but also improved survival rates.

Effects of Age, Sex, and Obesity on the Single-Dose Pharmacokinetics of Omarigliptin in Healthy Subjects

Omarigliptin is being developed as a potent, once-weekly, oral dipeptidyl peptidase-4 inhibitor for the treatment of type 2 diabetes. This double-blind, randomized, placebo-controlled study evaluated the effects of age, sex, and obesity on the pharmacokinetics of omarigliptin in healthy subjects. A single oral dose of omarigliptin 10 mg (n = 6/panel) or placebo (n = 2/panel) was administered in the fasted state to elderly nonobese men and women, young obese (30 ≤ body mass index [BMI] ≤ 35 kg/m(2) ) men and women, and young nonobese women of nonchildbearing potential. Plasma was collected at selected postdose times for evaluation of omarigliptin concentrations. Pharmacokinetic parameters were compared with historical data from a previously-conducted single-dose study in young, healthy, nonobese men. There were no clinically significant differences in omarigliptin AUC0-∞ , the primary pharmacokinetic parameter for assessing efficacy and safety, based on age, sex, or BMI (pooled nonobese elderly versus pooled nonobese young, young nonobese female versus young nonobese male, and pooled young obese versus pooled young nonobese). There were no serious adverse events or hypoglycemic events attributable to omarigliptin administration. Demographic factors and BMI had no meaningful effect on omarigliptin pharmacokinetics, suggesting that dose adjustment based on age, sex, or obesity is not required.

CYP3A4*22 and CYP3A5*3 are associated with increased levels of plasma simvastatin concentrations in the cholesterol and pharmacogenetics study cohort

Objective

Simvastatin is primarily metabolized by CYP3A4. A combined CYP3A4/5 genotype classification, combining the decrease-of-function CYP3A4*22 and the loss-of-function CYP3A5*3, has recently been reported. We aim to determine whether CYP3A4*22 and CYP3A5*3 alleles are associated with increased plasma concentrations of simvastatin lactone (SV) and simvastatin acid (SVA). This is the first report evaluating associations between in-vivo simvastatin concentrations and CYP3A4*22, alone or in a combined CYP3A4/5 genotype-defined classification.

Participants and methods

Genotypes and simvastatin concentrations were determined for 830 participants (555 Whites and 275 African-Americans) in the Cholesterol and Pharmacogenomics clinical trial with 40 mg/day simvastatin for 6 weeks. Concentrations were determined in 12-h postdose samples. Associations between simvastatin concentrations and CYP3A4*22 and CYP3A5*3 alleles were tested separately and in a combined CYP3A4/5 genotype-defined classification system.

Results

In Whites, CYP3A4*22 carriers (n=42) had 14% higher SVA (P=0.04) and 20% higher SV (P=0.06) compared with noncarriers (n=513). CYP3A5*3 allele status was not significantly associated with SV or SVA in Whites. In African-Americans, CYP3A4*22 carriers (n=8) had 170% higher SV (P<0.01) than noncarriers (n=267), but no significant difference was detected for SVA. African-American CYP3A5 nonexpressors (n=28) had 33% higher SV (P=0.02) than CYP3A5 expressors (n=247), but no significant difference was detected for SVA. For both races, SV appeared to decrease across the rank-ordered combined CYP3A4/5 genotype-defined groups (poor, intermediate, and extensive metabolizers); however, similar trends were not observed for SVA.

Conclusion

Genetic variation in CYP3A4 was associated with plasma simvastatin concentrations in self-reported Whites. Genetic variations in CYP3A4 and CYP3A5 were associated with plasma simvastatin concentrations in self-reported African-Americans.

Drug disposition in obesity: toward evidence-based dosing

Obesity and morbid obesity are associated with many physiological changes affecting pharmacokinetics, such as increased blood volume, cardiac output, splanchnic blood flow, and hepatic blood flow. In obesity, drug absorption appears unaltered, although recent evidence suggests that this conclusion may be premature. Volume of distribution may vary largely, but the magnitude and direction of changes seem difficult to predict, with extrapolation on the basis of total body weight being the best approach to date. Changes in clearance may be smaller than in distribution, whereas there is growing evidence that the influence of obesity on clearance can be predicted on the basis of reported changes in the metabolic or elimination pathways involved. For obese children, we propose two methods to distinguish between developmental and obesity-related changes. Future research should focus on the characterization of physiological concepts to predict the optimal dose for each drug in the obese population.

A Review of the Toxicologic Implications of Obesity

The increasing prevalence of obesity in developed nations has far-reaching implications for medical toxicology. The management of obese patients is complicated by comorbid illnesses, changes in cardiovascular and respiratory physiology, alterations in pharmacokinetics, and a lack of studies to identify appropriate dosing for current therapeutics and antidotes. In this review article, we examine obesity-associated physiologic and pharmacokinetic changes that may increase the vulnerability of obese patients to overdose. Further research is needed to characterize the relationship between drug toxicity and obesity.