Prospective evaluation of carboplatin AUC dosing in patients with a BMI>or=27 or cachexia

Serum and urinary biomarkers of vancomycin-induced acute kidney injury: A prospective, observational analysis

Vancomycin, a first-line drug for treating methicillin-resistant Staphylococcus aureus infections, is associated with acute kidney injury (AKI). This study involved an evaluation of biomarkers for AKI detection and their comparison with traditional serum creatinine (SCr). We prospectively enrolled patients scheduled to receive intravenous vancomycin for methicillin-resistant S aureus infection. Blood samples for pharmacokinetic assessment and SCr and cystatin C (CysC) measurements were collected at baseline and on days 3, 7, and 10 from the initiation of vancomycin administration (day 1). Urinary biomarkers, including kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin, and clusterin, were collected from days 1 to 7 and adjusted for urinary creatinine levels. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Of the 42 patients, 6 experienced vancomycin-induced AKI. On day 7, the change from baseline eGFR using CysC (ΔeGFRCysC) showed a stronger correlation with vancomycin area under the curve (r = -0.634, P < .001) than that using SCr (ΔeGFRSCr; r = -0.437, P = .020). ΔeGFRSCr showed no significant correlation with vancomycin pharmacokinetic in patients with body mass index ≥23. The median (interquartile range) level of KIM-1 (μg/mg) was significantly higher in the AKI group (0.006 [0.005-0.008]) than in the non-AKI group (0.004 [0.001-0.005]) (P = .039, Mann-Whitney U test), with area under the receiver operating characteristic curve (95% confidence interval) of 0.788 (0.587-0.990). Serum CysC, particularly in overweight individuals or those with obesity, along with urinary KIM-1 are important predictors of vancomycin-induced AKI. These results may aid in selecting better biomarkers than traditional SCr for detecting vancomycin-induced AKI.

Impact of weight and creatinine adjustments on the accuracy of Cockcroft-gault equation in hematopoietic cell transplant patients

BACKGROUND

Hematopoietic cell transplant (HCT) patients undergo pre- transplant renal function evaluation to confirm transplant eligibility and tailor pharmacotherapy. There is limited evidence regarding the most accurate method of estimating creatinine clearance (CrCl) within this patient population and no studies exist that evaluate the weight utilized within the Cockcroft-Gault (CG) equation in HCT patients. This study evaluates different weight and serum creatinine (SCr) adjustments utilized within the CG equation estimating for renal clearance in patients undergoing HCT.

OBJECTIVE

This is a retrospective, single center analysis of adult HCT patients who underwent pre-transplant evaluation with a measured CrCl using a 24-h urine creatinine collection. The primary outcome was to evaluate the correlation of various weights used in estimation of CrCl compared to measured CrCl. Key secondary outcomes include evaluation of the impact of various weights on estimated CrCl in subpopulations, evaluation of adjusting SCr to pre-determined limits, and determination of an appropriate obesity threshold to utilize body weight adjustments.

RESULTS

Seven-hundred and forty-two patients were included in the study. In the primary analysis, CG utilizing adjusted body weight (ADjBW0.4 ) had a greater correlation (r = .812) to measured CrCl when compared to total or ideal body weight (r = .801 and r = .790 respectively). The threshold of 120% of ideal body weight (IBW) produced less bias and greater accuracy in comparison to the threshold of 140% IBW. In patients 60 years or older, rounding low SCr values up .8 or 1 mg/dL resulted in decreased correlation and a greater mean difference in comparison to not rounding SCr.

CONCLUSION

In HCT patients who are overweight or obese, ADjBW .4 is the most accurate weight for the CG equation. In HCT patients who have a total body weight < 120% IBW, total body weight is the most accurate weight to utilize. Rounding up low SCr to .8 or 1 mg/dL does not improve the accuracy or led to less bias of the CG equation.

The association of body mass index with safety and effectiveness of first-line carboplatin-based chemotherapy in patients with metastatic non-small cell lung cancer

INTRODUCTION

Carboplatin is an anticancer drug used for treatment of various types of cancer including non-small cell lung cancer (NSCLC). Dosing is based on estimated glomerular filtration rate (GFR) using the Cockcroft-Gault formula. In overweight patients, the GFR is more likely overestimated, resulting in a potentially overdose of carboplatin affecting treatment response. This study investigated the association of body mass index (BMI) on overall survival (OS) and progression-free survival (PFS) in stage-IV NSCLC patients treated with first-line carboplatin-based chemotherapy. Secondary safety endpoints were thrombocytopenia and toxicity-related hospitalizations.

MATERIALS AND METHODS

This was a retrospective multicenter cohort study. Patients were categorized according to BMI<25.0 kg/m² (normal weight and reference), 25.0-29.9 kg/m² (overweight) or ≥30.0 kg/m² (obese). For survival analyses adjusted hazard ratios [aHR] were calculated using multivariate Cox regression analysis. Secondary outcomes were analyzed using multivariate logistic regression providing adjusted odd ratios [aOR].

RESULTS

Overweight patients (n=174) had a significantly better OS (aHR=0.72, 95%-CI:0.59-0.89) and PFS (aHR=0.74, 95%-CI:0.61-0.90) compared to normal weight patients (n=268). OS nor PFS were different in obese (n=51) compared to normal weight patients. However, obesity was associated with significantly higher incidences of thrombocytopenia grade ≥3 (aOR=3.47, 95%-CI:1.75-6.90).

CONCLUSION

This study shows a significantly longer survival for overweight compared to normal weight patients. Obese patients have an increased risk for grade ≥3 thrombocytopenia without a difference in survival following carboplatin-based chemotherapy. The implications for clinical practice are to use the Cockcroft-Gault formula with caution in patients with BMI≥30.0 kg/m², and to verify calculated dosing of carboplatin for appropriateness.

Carboplatin dose capping affects pCR rate in HER2-positive breast cancer patients treated with neoadjuvant Docetaxel, Carboplatin, Trastuzumab, Pertuzumab (TCHP)

PURPOSE

Estimated glomerular filtration rate (eGFR) is commonly used to calculate carboplatin doses and capping the eGFR may be used to reduce the risk of excessive dosing and toxicity. We sought to retrospectively examine the impact of our carboplatin guidelines on pathological complete response rates (pCR) and toxicity in women with HER2+ breast cancer receiving neoadjuvant docetaxel, carboplatin, trastuzumab and pertuzumab (TCHP).

METHODS

The delivered area under the curve (dAUC) was calculated [(actual carboplatin dose at cycle 1 ÷ dose calculated with uncapped/unbanded eGFR) × 6] and dichotomized at the median value. The impact of this and other clinical factors on pCR rate, dose intensity (DI) and toxicity was assessed.

RESULTS

124 eligible patients were identified of whom 63.7% (79/124) achieved pCR. The median dAUC at cycle 1 was 5.75 mg × ml/min. Those with lower dAUC were more frequently younger and overweight/obese. Patients with lower dAUC had significantly inferior pCR rates of 54.8% (34/62) vs 72.6% (45/62), respectively (p = 0.040). Similar results were seen in the ER+ subgroup; 45.2% (19/42) vs 68.3% (28/41), p = 0.037%, whereas no significant difference was seen among ER- patients; 75.0% (15/20) vs 81.0% (17/21), p = 0.72. DI and toxicity were comparable between the two dAUC groups.

CONCLUSIONS

The overall pCR rate was high in patients with HER2+ breast cancer receiving the TCHP regimen; however, carboplatin dose capping resulted in inferior pCR rates, particularly in the ER+ subgroup. To ensure optimal dosing, isotopic measurement of renal function is warranted in patients who would otherwise have their eGFR and dose capped.

Analysis of carboplatin dosing in patients with a glomerular filtration rate greater than 125 mL/min: To cap or not to cap? A retrospective analysis and review

The use of the Calvert formula to calculate carboplatin doses allows clinicians to achieve the appropriate carboplatin area under the concentration (AUC) curve. Thrombocytopenia is the dose limiting toxicity of carboplatin and optimizing AUC minimizes the risk of thrombocytopenia. Carboplatin clearance directly correlates with glomerular filtration rate (GFR) and, therefore, an accurate estimation of the renal function is needed. The Calvert formula was designed using the GFR measured by 51Cr-EDTA; however, many clinicians substitute estimated creatinine clearance (CrCl) as calculated by the Cockcroft–Gault (C–G) equation. The potential for overestimating AUC occurs when clinicians substitute actual weight in obese patients or use a low serum creatinine when calculating C–G estimated CrCl. In 2010, the National Cancer Institute recommended the GFR value within the Calvert formula should not exceed 125 mL/min, thereby capping the carboplatin dose. However, there are studies demonstrating that certain patients’ actual GFR values do exceed 125 mL/min. Therefore, capping the carboplatin dose in these patients may lead to underestimating the carboplatin AUC. A single-center, retrospective study was performed to evaluate the change in platelet count pre- and post-carboplatin exposure in patients with C–G estimated CrCl greater than 125 mL/min receiving capped versus uncapped carboplatin doses. A review of carboplatin dosing strategies is also presented. This study indicated there was a larger mean difference in pre- and post-platelet count in patients receiving uncapped carboplatin compared to patients receiving capped carboplatin with no differences in toxicities. Dose capping this patient population will likely lead to a lower AUC rather than the intended AUC target, which could ultimately lead to substandard outcomes.

Variability of carboplatin dose calculation methods in Spain

OBJECTIVE

To describe and analyze the variability in carboplatin dosing strategies in Spanish hospitals.

METHODS

We designed a questionnaire consisting of 19 multiple-choice items structured in two sections (hospital characteristics and carboplatin dosing data). The questionnaire was sent by e-mail to all the oncology pharmacists included in the register of the Spanish Oncology Pharmacy Group (GEDEFO), and we analyzed the completed questionnaires.

RESULTS

Response rate was 33.5% from a total of 185 pharmacy services invited to take part in the survey. All hospitals used the Calvert formula to calculate carboplatin dose with glomerular filtration rate estimated by a formula, most commonly the Cockcroft-Gault equation (80.7%). Carboplatin doses were capped in most hospitals (91.9%): 54.8% capped creatinine clearance at 125 mL/min, 11.3% capped serum creatinine, and 19.3% capped both creatinine clearance and serum creatinine. Serum creatinine cut-off values ranged from 0.36 mg/dL to 1 mg/dL. The most commonly used body weight was actual body weight for underweight, normal weight, and overweight patients. The use of adjusted ideal body weight increased in obese and especially in morbidly obese patients.

CONCLUSION

The results from this survey show the variability that exists in carboplatin dose calculation methods among Spanish hospitals and the need to continue investigating to find the optimum dose calculation method and unify criteria to avoid differences between sites that can affect effectiveness and toxicity of carboplatin-containing treatments.

Toxicity and effectiveness of carboplatin in obese or overweight patients

OBJECTIVE

To evaluate the efficiency and toxicity of carboplatin using actual body weight in obese/overweight patients using the Calvert formula with Cockcroft-Gault for CrCl estimation.

METHODS

We evaluated the association of BMI in regards to efficiency and toxicity in a retrospective cohort study of patients who started treatment with carboplatin between 2012 and 2013. Cohorts included obese/overweight patients and normal-weight patients. Efficiency was measured by overall survival, progression-free survival and response rate. Toxicity was measured by the proportion of dose reductions and delays of chemotherapy cycles. We utilized a bivariate and multivariate analysis.

RESULTS

Eighty-six patients were included in the study (50% obese/overweight). There was not a statistically significant difference in effectiveness and toxicity between the two groups in BMI. In the multivariate analysis, BMI not was associated with overall survival (hazard ratio: 0.95, 95% CI: 0.54-1.66, p = 0.849), progression-free survival (hazard ratio: 0.91; 95% CI: 0.54-1.54; p = 0.732), cycle delays (odds ratio (OR): 1.47, 95% CI: 0.80-2.69, p = 0.218) or carboplatin dose reductions (OR: 0.87, 95% CI: 0.35-2.15, p = 0.760). Response rate was 53.5% in both groups.

CONCLUSIONS

In our study, obese and overweight cancer patients did not show a statistically significant difference in terms of effectiveness and toxicity compared to normal-weight cancer patients who were treated with carboplatin using their actual body weight with the Calvert formula and Cockcroft-Gault for CrCl estimation. Therefore, it was appropriate to use the actual body weight for our patients.

Utility of physiologically based pharmacokinetic (PBPK) modeling in oncology drug development and its accuracy: a systematic review

PURPOSE

Physiologically based pharmacokinetic (PBPK) modeling, a mathematical modeling approach which uses a pharmacokinetic model to mimick human physiology to predict drug concentration-time profiles, has been used for the discover and development of drugs in various fields, including oncology, since 2000. There have been a few general review articles on the utilization of PBPK in the development of oncology drugs, but these do not include an evaluation of model prediction accuracy. We therefore conducted a systematic review to define the accuracy of PBPK model prediction and its utility throughout all the developmental phases of oncology drugs.

METHODS

A systematic search was performed in the PubMed, PubMed Central and Cochrane Library databases from 1980 to February 2017 for articles (1) written in English, (2) focused on oncology or antineoplastic or anticancer drugs, tumor or cancer or anticancer drugs listed in the U.S. National Institutes of Health and (3) involving a PBPK model. The absolute-average-folding-errors (AAFEs) of the area under the curve (AUC) between predicted and observed values in each article were calculated to assess model prediction accuracy.

RESULTS

Of the 2341 articles initially identified by our search of the databases, 40 were included in the review analysis. These articles reported on six types of studies, i.e. in vivo (n = 4), first-in-human (n = 5), phase II/III clinical trials (n = 9), organ impairment (n = 3), pediatrics (n = 4) and drug-drug interactions (n = 15). AAFEs of the predicted AUC for all groups of studies were within 1.3-fold of each other despite variations in experimental methodologies.

CONCLUSION

PBPK modeling is a potential tool which can be effectively applied throughout all phases of oncology drug development. The number of experimental animals and human participants enrolled in the studies can be reduced using PBPK modeling and PBPK-population-PK modeling. The limited number of publications of unsuccessful model application to date may contribute to bias toward the usefulness of modeling.

Creation and evaluation of a cancer chemotherapy order review guide for use at a community hospital

The proper evaluation of cancer chemotherapy orders is necessary for patients to receive safe and effective treatment. The chemotherapy treatment setting is evolving resulting in hospital pharmacists without extensive oncology training or experience now being responsible for evaluation of chemotherapy orders. The primary objective was to create a step-by-step chemotherapy order evaluation guide with a detailed explanation for each step. The secondary objective was to evaluate non-oncology trained pharmacists' ability to accurately review simulated chemotherapy orders post-education using the guide. A two-page chemotherapy order evaluation guide was created based on an accepted method of chemotherapy order review consisting of the following eight steps: regimen verification, clinical trial protocol verification, body surface area calculation, dose calculation, laboratory values, emesis prophylaxis, adjunctive or supportive care measures, and pharmacy labels. A literature search was performed for each step. A detailed explanation for each step was written as a separate component from the guide to encompass the literature search information and current guidelines in a more comprehensive manner. Non-oncology trained community hospital pharmacists were educated on use of the guide for approximately 30 min. The guide was evaluated using timed simulated chemotherapy orders pre- and post-education consisting of a general chemotherapy order and a carboplatin dosing order. Nineteen pharmacists were tested with simulated chemotherapy orders. A significant difference was detected between the pre- and post-education for both the general chemotherapy (p = 0.00032) order and carboplatin dosing order (p = 0.031).

Carboplatin and Liposomal Doxorubicin for Ovarian Cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Dose-banding of carboplatin: rationale and proposed banding scheme

Background. In dose-banding (DB) prescribed doses of cancer chemotherapy are fitted to doseranges or ‘bands’ and standard doses for each band are provided using a selection of pre-filled infusions or syringes, either singly or in combination. DB is used for several drugs where dose is based on body surface area. No DB-scheme has been reported for carboplatin, which, in clinical practice, is routinely dosed according to renal function.

Study objective. To assess the rationale for DB of carboplatin with regards to factors that influence dosing accuracy, develop a DB scheme, and discuss its potential use and limitations.

Methods. Prospective evaluations of carboplatin area under the plasma concentration – time curve (AUC) following application of the Calvert-formula were identified by a literature search. A relevant carboplatin dose range for construction of a DB-scheme with Calvert-formula based doses was obtained from published glomerular filtration rate distributions for patients receiving carboplatin.

Results. A DB-scheme was developed for individually calculated carboplatin doses of 358–1232 mg, with 35 mg increments between each standard dose and a maximum deviation of 4.7% from prescribed dose. The proposed DB-scheme covers the GFR-ranges 47–221 mL/min and 26–151 mL/min for patients receiving doses based on the target AUCs of 5 and 7 mg/mL/min, respectively.

Conclusion. There is a strong scientific rationale to support DB of carboplatin. The proposed banding scheme could introduce benefits to patients and healthcare staff but, as with other DB schemes, should be validated with prospective clinical and pharmacokinetic studies to confirm safety and efficacy.

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.

Gemcitabine and Carboplatin (renally dosed) regimen for bladder cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Nab-Paclitaxel and Carboplatin (Nab-PC) Regimen for Advanced Non-Small-Cell Lung Cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Irinotecan and Carboplatin (IC) Regimen for Small-Cell Lung Cancer and Non-Small-Cell Lung Cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Paclitaxel, Carboplatin, and trastuzumab

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Paclitaxel and Carboplatin (TC) Regimen for Ovarian Cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Carboplatin (renally dosed) and Etoposide regimen for small-cell lung cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc, 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Pharmacokinetics of drugs in cachectic patients: a systematic review

Cachexia is a weight-loss process caused by an underlying chronic disease such as cancer, chronic heart failure, chronic obstructive pulmonary disease, or rheumatoid arthritis. It leads to changes in body structure and function that may influence the pharmacokinetics of drugs. Changes in gut function and decreased subcutaneous tissue may influence the absorption of orally and transdermally applied drugs. Altered body composition and plasma protein concentration may affect drug distribution. Changes in the expression and function of metabolic enzymes could influence the metabolism of drugs, and their renal excretion could be affected by possible reduction in kidney function. Because no general guidelines exist for drug dose adjustments in cachectic patients, we conducted a systematic search to identify articles that investigated the pharmacokinetics of drugs in cachectic patients.

Carboplatin (renally dosed) and Etoposide regimen for small-cell lung cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc, 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Carboplatin dose calculation in lung cancer patients with low serum creatinine concentrations using CKD-EPI and Cockcroft-Gault with different weight descriptors

STUDY OBJECTIVES

Carboplatin dosing using the Calvert and Cockcroft-Gault formulae in patients with low serum creatinine levels is discussed controversially. We conducted a retrospective analysis applying the CKD-EPI formula and the alternate size descriptors adjusted body weight and predicted normal weight in the Cockcroft-Gault equation for calculating the carboplatin dose.

METHODS

Data were collected retrospectively from 128 lung cancer patients with serum creatinine <0.8 mg/dL (71 μmol/L) who had received chemotherapy that was mostly platinum-based. Serum creatinine concentration for renal function estimation and measured creatinine clearance (24-h urine collection) were available on the same day from these patients. Actual doses were calculated based on the Cockcroft-Gault formula with total body weight. For the study purpose doses were recalculated using Cockcroft-Gault with adjusted body weight and predicted normal weight and CKD-EPI. Subgroup analyses were performed for gender and body mass index.

RESULTS

All alternate dose calculations were not inferior to the calculation based on Cockcroft-Gault using total body weight. In overweight and obese patients they were superior in reducing mean overdose from 24% to roughly 15% (predicted normal weight, CKD-EPI) and 10% (adjusted body weight) and from 25% to 9%, 8% and 4%, respectively. Best performed the combination of Cockcroft-Gault with adjusted body weight.

CONCLUSION

The results show that application of the alternate size descriptor adjusted body weight in the Cockcroft-Gault equation can improve dosing accuracy especially in overweight and obese patients with low serum creatinine levels.

Features of cancer management in obese patients

There is worldwide increased in obesity prevalence and statistical almost half of United-States, including children, could be obese by 2050. Obesity in cancer patients is a major issue in oncology because weight gain and obesity account for approximately 20% of all cancer cases. Indeed, increased obesity is linked with higher risk of various types of cancer and a poorer survival. Although biological mechanisms underlying how obesity causes an increased risk of cancer are suggested, overweight as a putative direct cause of death is still debated. Numerous confounding factors may impact on survival, including comorbidities and imaging limitations. Moreover, difficulties to achieve the standard oncologic care with surgery, chemotherapy and/or radiation may also be concerned. Herein, we examined the specific features and potential adaptation of the cancer management in overweighed patients. Then, we reviewed how implicated molecular pathways may provide new strategies to decrease cancer risk and predict toxicities in an increasingly obese population.

The two major epidemics of the twenty-first century: obesity and cancer

It is a well-known fact that severe obesity is associated with the metabolic syndrome, type 2 diabetes, cardiovascular disease, hypertension, and other diseases. Epidemiological studies have suggested that obesity is also associated with increased risk of several cancer types. The number of people who are suffering from severe obesity is growing, and clinical data suggest that severely obese patients belong to a unique population with regards to risk, efficacy of screening, and cancer treatment. This review will point out the potential mechanism linking obesity and cancer and will discuss several challenges in various treatment modalities of cancer in obese patients.

Adipocytes impair leukemia treatment in mice

Obesity is associated with increased cancer incidence and mortality. We have previously found that obesity in children is associated with a 50% increased recurrence of acute lymphoblastic leukemia (ALL) in high-risk patients. We have therefore developed novel in vivo and in vitro preclinical models to study the mechanism(s) of this association. Obesity increased relapse after monotherapy with vincristine (P = 0.03) in obese mice injected with syngeneic ALL cells. This occurred although the drug was dosed proportionally to body weight, equalizing blood and tissue drug levels. In coculture, 3T3-L1 adipocytes significantly impaired the antileukemia efficacy of vincristine, as well as three other chemotherapies (P < 0.05). Interestingly, this protection was independent of cell-cell contact, and it extended to human leukemia cell lines as well. Adipocytes prevented chemotherapy-induced apoptosis, and this was associated with increased expression of the two prosurvival signals Bcl-2 and Pim-2. These findings highlight the role of the adipocyte in fostering leukemia chemotherapy resistance, and may help explain the increased leukemia relapse rate in obese children and adults. Given the growing prevalence of obesity worldwide, these effects are likely to have increasing importance to cancer treatment.

A phase I pharmacokinetic and pharmacodynamic correlative study of the antisense Bcl-2 oligonucleotide g3139, in combination with carboplatin and paclitaxel, in patients with advanced solid tumors

PURPOSE

This phase I trial assessed the safety and tolerability of G3139 when given in combination with carboplatin and paclitaxel chemotherapy. The effect of G3139 treatment on Bcl-2 expression in peripheral blood mononuclear cells (PBMC) and paired tumor biopsies was also determined.

EXPERIMENTAL DESIGN

Patients with advanced solid malignancies received various doses of G3139 (continuous i.v. infusion days 1-7), carboplatin (day 4), and paclitaxel (day 4), repeated in 3-week cycles, in a standard cohort-of-three dose-escalation schema. Changes in Bcl-2/Bax transcription/expression were assessed at baseline and day 4 (prechemotherapy) in both PBMCs and paired tumor biopsies. The pharmacokinetic interactions between G3139 and carboplatin/paclitaxel were measured.

RESULTS

Forty-two patients were evaluable for safety analysis. Primary toxicities were hematologic (myelosuppression and thrombocytopenia). Dose escalation was stopped with G3139 at 7 mg/kg/d, carboplatin at area under the curve of 6, and paclitaxel at 175 mg/m(2) due to significant neutropenia seen in cycle 1 and safety concerns in further escalating chemotherapy in this phase I population. With G3139 at 7 mg/kg/d, 13 patients underwent planned tumor biopsies, of which 12 matched pairs were obtained. Quantitative increases in intratumoral G3139 with decreases in intratumoral Bcl-2 gene expression were seen. This paralleled a decrease in Bcl-2 protein expression observed in PBMCs.

CONCLUSIONS

Although the maximal tolerated dose was not reached, the observed toxicities were consistent with what one would expect from carboplatin and paclitaxel alone. In addition, we show that achievable intratumoral G3139 concentrations can result in Bcl-2 down-regulation in solid tumors and PBMCs.

[Retrospective analysis of the carboplatin dosage and relationship with toxicity in cancer patients]

OBJECTIVE

To analyse carboplatin dosage in cancer patients in order to establish whether they are over- or underdosed in comparison to the theoretical dose calculations during the first cycle of chemotherapy and to find a relationship between the dosage in the first cycle and dose reduction in subsequent cycles, as a result of adverse effects related to the same.

METHOD

Retrospective analysis over a one year period of prescriptions of chemotherapy with carboplatin. Patients were stratified into 4 groups according to body mass index and serum creatinine values. The mean percent error (MPE) was used to determine the relationship between the dose received and the theoretical dose calculation during the first cycle. The Mann-Whitney U test was used to study the possible relationship between patients dosage during the first cycle and dose reduction in subsequent cycles.

RESULTS

A total of 86 patients were selected. Only the cohort of patients who were overweight/obese showed significant differences between the theoretical dose calculation and the dose actually received. The mean MPE value with the standard error for this group was 7.963 +- 2.610%. No links were found with the dose reduction in subsequent cycles for this cohort of patients.

CONCLUSIONS

Not using adjusted weight or serum creatinine values in the Cockcroft-Gault equation may lead to incorrect doses of carboplatin in obese patients. Studies including a larger number of patients are required to confirm the relationship between overdosing during the first cycle and dose reduction in subsequent cycles, as a result of carboplatin toxicity.

Chemotherapy Dosing Part II: Alternative Approaches and Future Prospects

This overview follows on from part I, which described the current practices used in chemotherapy dosing and the paucity of scientific evidence to support them. In part II, alternative approaches are discussed, both in terms of scientific rationale and practical application. These include therapeutic drug monitoring, the use of pharmacokinetic-pharmacodynamic relationships, flat-fixed dosing, Bayesian modelling and dose banding.