Novel algorithm for more accurate calculation of renal function in adults with cancer

Sarcopenia as a Predictive Factor for Carboplatin Toxicity in Patients with Advanced Non-Small Cell Lung Cancer

Sarcopenia in cancer patients often negatively impacts various outcomes. Carboplatin, a first-line chemotherapy for non-small cell lung cancer (NSCLC), is dosed based on body weight, which doesn't account for sarcopenia. This study evaluated the association between sarcopenia and carboplatin-related toxicity in NSCLC patients. Patients with locally advanced or metastatic NSCLC treated with carboplatin were included. Toxicity events during the first two cycles of treatment were recorded. Sarcopenia was assessed using pretreatment computed tomography scans analyzed with Slice-O-Matic V4.2 software, defining sarcopenia as a skeletal muscle index (SMI) of <52.4 cm2/m2 for men and <38.5 cm2/m2 for women. Among 146 patients, 52% had sarcopenia. Hematological toxicity occurred in 71.2% of all patients and 77.6% of those with sarcopenia. The fat-free mass index (FFMI) was independently associated with hematological toxicity and dose-limiting toxicity (DLT), which was observed in 55.5% of patients. Sarcopenia significantly correlates with hematological toxicity and DLT during carboplatin treatment in NSCLC patients. Given its prevalence and noninvasive detection, further research is needed to understand its impact on treatment outcomes.

Carboplatin dosing in the treatment of ovarian cancer: An NRG oncology group study

OBJECTIVE

To determine the effects of using National Comprehensive Cancer Network (NCCN) guidelines to estimate renal function on carboplatin dosing and explore adverse effects associated with a more accurate estimation of lower creatinine clearance (CrCl).

METHODS

Retrospective data were obtained for 3830 of 4312 patients treated on GOG182 (NCT00011986)-a phase III trial of platinum-based chemotherapy for advanced-stage ovarian cancer. Carboplatin dose per patient on GOG182 was determined using the Jelliffe formula. We recalculated CrCl to determine dosing using Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (with/without NCCN recommended modifications) formulas. Associations between baseline CrCl and toxicity were described using the area under the receiver operating characteristic curve (AUC). Sensitivity and positive predictive values described the model's ability to discriminate between subjects with/without the adverse event.

RESULTS

AUC statistics (range, 0.52-0.64) showed log(CrClJelliffe) was not a good predictor of grade ≥3 adverse events (anemia, thrombocytopenia, febrile neutropenia, auditory, renal, metabolic, neurologic). Of 3830 patients, 628 (16%) had CrCl <60 mL/min. Positive predictive values for adverse events ranged from 1.8%-15%. Using the Cockcroft-Gault, Cockcroft-Gault with NCCN modifications, and MDRD (instead of Jelliffe) formulas to estimate renal function resulted in a >10% decrease in carboplatin dosing in 16%, 32%, and 5.2% of patients, respectively, and a >10% increase in carboplatin dosing in 41%, 9.6% and 12% of patients, respectively.

CONCLUSION

The formula used to estimate CrCl affects carboplatin dosing. Estimated CrCl <60 mL/min (by Jelliffe) did not accurately predict adverse events. Efforts continue to better predict renal function. Endorsing National Cancer Institute initiatives to broaden study eligibility, our data do not support a minimum threshold CrCl <60 mL/min as an exclusion criterion from clinical trials.

Failure to predict amikacin elimination in critically ill patients with cancer based on the estimated glomerular filtration rate: applying PBPK approach in a therapeutic drug monitoring study

PURPOSE

The aim of this work was to integrate the Therapeutic Drug Monitoring (TDM) with the model-informed precision dosing (MIPD) approach, using Physiologically-based Pharmacokinetic/Pharmacodynamic (PBPK/PD) modelling and simulation, to explore the relationship between amikacin exposure and estimated glomerular filtration rate (GFR) in critically ill patients with cancer.

METHODS

In the TDM study, samples from 51 critically-ill patients with cancer treated with amikacin were analysed. Patients were stratified according to renal function based on GFR status. A full-body PBPK model with 12 organs model was developed using Simcyp V. 21, including steady-state volume of distribution of 0.21 L/kg and renal clearance of 6.9 L/h in healthy adults. PK parameters evaluated were within the 2-fold error range.

RESULTS

During the validation step, predicted vs observed amikacin clearance values after single infusion dose in patients with normal renal function, mild and moderate renal impairment were 7.6 vs 8.1 L/h (7.5 mg/kg dose); 3.8 vs 4.5 L/h (1500 mg dose) and 2.2 vs 3.1 L/h (25 mg/kg dose), respectively. However, predicted vs observed amikacin clearance after a single dose infusion of 1400 mg in critically-ill patients with cancer were 1.46 vs 1.63 (P = 0.6406) L/h (severe), 2.83 vs 1.08 (P < 0.05) L/h (moderate), 4.23 vs 2.49 (P = 0.0625) L/h (mild) and 7.41 vs 3.36 (P < 0.05) L/h (normal renal function).

CONCLUSION

This study demonstrated that estimated GFR did not predict amikacin elimination in critically-ill patients with cancer. Further studies are necessary to find amikacin PK covariates to optimize the pharmacotherapy in this population. Therefore, TDM of amikacin is imperative in cancer patients.

Renal Function Assessment Gap in Clinical Practice: An Awkward Truth

INTRODUCTION

An accurate assessment of renal function is needed in the majority of clinical settings. Unfortunately, the most used estimated glomerular filtration rate (eGFR) formulas are affected by significant errors in comparison to gold standards methods of measured GFR (mGFR).

OBJECTIVE

The objective of the study is to determine the extent of the error of eGFR formulas compared to the mGFR in different specific clinical settings.

METHODS

A total retrospectively consecutive cohort of 1,320 patients (pts) enrolled in 2 different European Hospitals (Center 1: 470 pts; Center 2: 850 pts) was collected in order to compare the most common eGFR formulas used by physicians with the most widespread mGFR methods in daily clinical practice (Iohexol Plasma Clearance -Center 1 [mGFR-iox] and Renal Scintigraphy -Center 2 [mGFR-scnt]). The study cohort was composed by urological, oncological, and nephrological pts. The agreement between eGFR and mGFR was evaluated using bias (as median of difference), precision (as interquartile range of difference) accuracy (as P30), and total deviation index.

RESULTS

The most accurate eGFR formula in the comparison with gold standard method (Iohexol plasma clearance) in Center 1 was represented by s-creatinine and cystatin C combined Chronic Kidney Disease-Epidemiology Collaboration-cr-cy, even though the P30 is reduced (84%) under the threshold of 60 mL/min/1.73 m2. Similar results were found in Center 2, with a wider discrepancy between mGFR-scnt and eGFR formulas due to the minor accuracy of the nuclear tool in respect to the mGFR-iox.

CONCLUSIONS

The loss of accuracy observed for the formulas at lower values of GFR suggests the mandatory use of gold standards methods as Iohexol Plasma Clearance to assess the correct status of renal function for critical cases. The center 2 showed lower levels of agreement between mGFR and eGFR suggesting that the errors are partially accounted for the Renal Scintigraphy technique too. In particular, we suggest the use of mGFR-iox in oncological urological and nephrological pts with an eGFR lower than 60 mL/min/1.73 m2.

Assessment of Kidney Function in Patients With Cancer

Cancer patients are living longer. The sequelae of cancer treatment and the role of comorbid conditions present before the diagnosis, such as CKD, have been increasingly recognized. The interface between CKD and cancer is multifaceted. CKD is frequently observed in patients with cancer, and cancer treatment contributes to CKD development and progression. In addition, CKD has been recognized as an important risk factor for cancer development and reduced specific cancer survival. In this context, an accurate evaluation of the glomerular filtration rate (GFR) during oncologic treatment is pivotal and is used to define surgery strategies, program prophylactic management of contrasted examinations, make decisions on cisplatin eligibility, and adjust drug prescriptions, particularly chemotherapy agents. Although the most commonly used equations to estimate GFR based on serum creatinine levels in clinical practice (Cockcroft-Gault, Modification of Diet in Renal Disease Study, and CKD Epidemiology Collaboration equations) have not been validated in patients with cancer in large prospective studies, there is increasingly evidence supporting the use of CKD Epidemiology Collaboration equation to assess the GFR in patients with cancer, including for the use of chemotherapy prescriptions. Many patients with cancer may have changes in nutrition status and clearance measurements such as exogenous filtration markers might be extremely useful when clinical decisions differ depending on the GFR level. Future perspectives include the advent of new serum GFR biomarkers such as cystatin C, beta-trace protein, and beta-2 microglobulin as well as the GFR assessment by measuring total kidney parenchymal volume through image examinations.

Introduction to the Journal of Onco-Nephrology

Renal insufficiency is highly prevalent among cancer patients, which negatively impacts on their survival. Furthermore, many oncological treatments may severely impair kidney function or exasperate preexisting renal diseases.

Thus, the relationship between cancer and the kidney could be regarded as “circular” and warrants specific competencies and expertise for its management.

This is why onco-nephrology, as a subspecialty of both oncology and nephrology, has begun to gain importance over the past few years.

The complex issues of the management of cancer patients in dialysis, of candidates for kidney transplantation who have had a previous malignancy, and of transplant recipients who subsequently develop a malignancy, also fall into the field of onco-nephrology.

Renal insufficiency and cancer treatments

Renal insufficiency has been shown to be highly prevalent in patients with cancer. This renal insufficiency has been reported to be associated with reduced overall survival and increased cancer-related mortality. Therefore, it is important to screen patients with cancer for renal insufficiency, using an adequate and reliable method of estimation of the renal function. Renal insufficiency may influence 1 or several of the 4 pharmacokinetic phases (absorption, distribution, metabolism, elimination/excretion), potentially resulting in marked modifications of the pharmacokinetic profile of a drug in patients with renal insufficiency. Consequently, it is potentially necessary to adjust the dosage of anticancer drugs in case of renal insufficiency in order to avoid drug accumulation and in order to reduce overdosage-related side effects. This dosage adjustment of anticancer drugs should be performed according to the level of renal function and with an appropriate and validated method. It is not always easy to find clear information on anticancer drug handling in these patients. However, several guidelines, publications and handbooks are available on how to adjust anticancer drug dosages in patients with renal insufficiency and will help practitioners to manage anticancer drugs in such patients.

Development of a new equation to estimate creatinine clearance in cancer patients

PURPOSE

Determining renal function is important for chemotherapy eligibility and dosing. Measured creatinine clearance (mCrCl) is the gold standard but is cumbersome. Equations estimating CrCl (eCrCl) based on serum creatinine (SCr) produce widely varying estimates. Considering that SCr is derived from skeletal muscle, this study prospectively developed a new eCrCl equation in cancer patients using CT-defined muscle surface area (MSA) and evaluated its utility in a separate, retrospective series.

METHODS

In a prospective, observational cohort study of cancer patients, mCrCl by 24-h urine collection was correlated with CT-determined MSA to create an equation for eCrCl [muscle surface area (cm(2)) × 42/SCr]. eCrCl by Wright, Cockcroft-Gault (CG), CKD-EPI, MDRD, and MSA was compared to mCrCl to determine fit. MSA-eCrCl was used to simulate carboplatin dosing in a retrospective series of advanced non-small cell lung cancer (NSCLC).

RESULTS

Prospectively, 22 patients were accrued and evaluable (12 males; median age 69). MSA-eCrCl correlated stronger (r (2) 0.80) than current equations (r (2) 0.47-0.69) with mCrCl. In calculating carboplatin doses for 89 NSCLC patients with MSA and CG-eCrCl, median error of CG-determined carboplatin dose was 5.5 % (range -19.0 to 44.2 %), assuming that MSA was better at estimating CrCl. Forty-two patients (47 %) received doses that varied ≥10 % of what was calculated by MSA.

CONCLUSIONS

We propose a new formula for eCrCl in patients that appears more accurate than current formulae and may have implications for chemotherapy efficacy and toxicity. Studies to validate this formula are under way.

Nephrotoxicity of recent anti-cancer agents

Cancer patients may develop a variety of kidney lesions that impair not only their immediate survival but also limit the adequate treatment of the underlying malignant process. This review summarizes the nephrotoxic potential of some of the most recently developed anti-cancer drugs, focusing on those interfering with the vascular endothelial growth factor and epidermal growth factor receptor pathways and mammalian target of rapamycin inhibitors. Thrombotic microangiopathy (haemolytic-uraemic syndrome), proteinuria, hypertension and magnesium depletion are the most common side effects. Also the risk for developing acute kidney injury in patients with advanced prostate cancer undergoing androgen deprivation therapy is discussed.

Impact of chronic kidney disease on the risk of clinical outcomes in patients with cancer-associated venous thromboembolism during anticoagulant treatment

BACKGROUND

Information on recurrent venous thromboembolic events (VTEs) and major bleeding risks during anticoagulant treatment in patients with cancer-associated VTEs and chronic kidney disease (CKD) is scarce, although it is of relevance in establishing better tailored management strategies in these patients.

OBJECTIVES

We compared risks of recurrent VTEs and major bleeds in cancer-associated VTE patients with and without CKD.

METHODS

A total of 1684 patients diagnosed with a cancer-associated VTE between 2001 and 2011 were followed for 180 days after VTE diagnosis. Patients were treated mainly with low-molecular-weight heparin (LMWH) or vitamin-K antagonists (VKA). Primary outcomes were recurrent VTE and major bleeding. Secondary outcome was fatal bleeding.

RESULTS

Recurrent VTEs occurred in 15.9/100 patient years (py) in patients without CKD (eGFR > 60 mL min(-1) ), 19.5/100 py in those with CKD stage 3A (eGFR 45-60 mL min(-1) ), 14.9/100 py in those with CKD 3B (eGFR 30-45 mL min(-1) ), and 6.8/100 py in patients with CKD 4-5 (eGFR < 30 mL min(-1) ). Major bleeding occurred in 11.4/100 py in patients without CKD, 18.5/100 py in those with CKD stage 3A, 16.0/100 py in those with CKD 3B, and 40.8/100 py in patients with CKD 4-5. Fatal bleeding occurred in 1.1/100 py, 3.4/100 py, 6.3/100 py and 15.7/100 py, respectively. These increased bleeding risks in CKD patients were mainly observed in those on LMWH treatment, not VKA.

CONCLUSIONS

The risk of major bleeding was increased in CKD patients with VTE and cancer, and was most prominent in those treated with LMWH and an eGFR < 30 mL min(-1) . These results indicate that LMWH should be used with caution in this specific population.

Evaluation of glomerular filtration rate estimation by Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

BACKGROUND

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA.

PATIENTS AND METHODS

Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR.

RESULTS

Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min.

CONCLUSIONS

When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.

Effect of age on systemic exposure and haematological toxicity of carboplatin in advanced non-small cell lung cancer patients

The aim of this study was to evaluate systemic exposure to carboplatin and its haematological toxicity in patients with advanced non-small cell lung cancer both older and younger than 70 years when the target area under the curve (AUC) in elderly patients was reduced by 20%. For this purpose, a population pharmacokinetic model was developed and the haematological toxicity of the drug was assessed. A total of 33 patients received carboplatin on day 1 and gemcitabine (1250 mg/m(2) ) on days 1 and 8. This schedule was repeated every 21 days. The Calvert-Crokcoft-Gault formula was employed to calculate a dose of carboplatin with a target AUC of 5 mg/min./mL in patients under 70 years and 4 mg/min./mL in patients aged 70 or older. The data of 24 patients were treated for population modelling performed with the nonmem (University of California, San Francisco, CA, USA) approach. Haematological toxicity was evaluated for all 33 patients enrolled in the study. The carboplatin systemic exposure measured by the AUC (mg/min./mL) was 5.98 (5.45; 6.51) and 5.36 (5.02; 5.69) for the younger patients and older groups, respectively. No significant differences were observed between the two groups with respect to rates of grade 3+ anaemia, neutropenia or thrombocytopenia. In clinical practice, a target AUC of 4 mg/min./mL carboplatin is applied to patients aged 70 and over, but the actual systemic exposure to the drug is higher. This supports a target AUC of 4 mg/min./mL carboplatin for patients older than 70 years when the dose is calculated by means of the Calvert-Crokcoft-Gault formula.

Cancer and renal insufficiency results of the BIRMA study

Background:

Half of anticancer drugs are predominantly excreted in urine. Dosage adjustment in renal insufficiency (RI) is, therefore, a crucial issue. Moreover, patients with abnormal renal function are at high risk for drug-induced nephrotoxicity. The Belgian Renal Insufficiency and Anticancer Medications (BIRMA) study investigated the prevalence of RI in cancer patients, and the profile/dosing of anticancer drugs prescribed.

Methods:

Primary end point: to estimate the prevalence of abnormal glomerular filtration rate (GFR; estimated with the abbreviated Modification of Diet in Renal Disease formula) and RI in cancer patient. Secondary end point: to describe the profile of anticancer drugs prescribed (dose reduction/nephrotoxicity). Data were collected for patients presenting at one of the seven Belgian BIRMA centres in March 2006.

Results:

A total of 1218 patients were included. The prevalence of elevated SCR (⩾1.2 mg per 100 ml) was 14.9%, but 64.0% had a GFR<90 ml min⁻¹ per 1.73 m². In all, 78.6% of treated patients (n=1087) were receiving at least one drug needing dosage adjustment and 78.1% received at least one nephrotoxic drug. In all, 56.5% of RI patients receiving chemotherapy requiring dose reduction in case of RI did not receive dose adjustment.

Conclusions:

The RI is highly frequent in cancer patients. In all, 80% of the patients receive potentially nephrotoxic drugs and/or for which dosage must be adjusted in RI. Oncologists should check the appropriate dose of chemotherapeutic drugs in relation to renal function before prescribing.

Evaluation of creatinine-based formulas in dosing adjustment of cancer drugs other than carboplatin

Background. Glomerular filtration rate (GFR) is often used to determine initial dosing of renally excreted cancer drugs. GFR can be calculated using the Cockcroft-Gault (CG) or the modified diet in renal diseases (MDRD) study formulas, both of which are based on serum creatinine levels. The MDRD formula is more accurate in noncancer patients, does not require patient weight, and is reported automatically by all laboratories in British Columbia, Canada. We previously showed that the CG and MDRD formulas have similar accuracy for carboplatin dosing in patients with gynecological malignancies. We now examine dosing of all renally excreted cancer drugs in the general cancer population. Since this setting does not include routine measurement of GFR, we report the concordance of estimates of GFR derived from the CG and MDRD formulas.

Methods. Patient data were collected retrospectively at the BC Cancer Agency. The primary outcome was the proportion of patients who would have received a different initial dose due to difference in the GFR. Each patient’s dose was determined from dose adjustment tables stated in specific treatment protocols. The secondary outcome was concordance of the GFR derived from CG and MDRD, using the method of Bland and Altman. A difference of >30% was assumed to be clinically significant because this difference would usually lead to dose adjustment based on reclassification of renal function.

Results. A total of 313 patients were evaluated, with 40% male. The median age was 56 years, weight 67.5 kg, height 166 cm, and serum creatinine 74 µmol/L (0.84 mg/dL). The median GFR derived from the CG and MDRD formulas were 86.8 mL/min (mean 91 mL/min, SD ± 30 mL/min) and 87.6 mL/min (mean 88 mL/min, SD ± 26 mL/min), respectively. A total of 8.6% (27/313) of patients would have received a different dose due to difference in the GFR; of these, 67% (18/27) would have received a higher dose. A difference of >30% in GFR was found in 17.9% (56/313) of patients.

Conclusions. There is good concordance of the GFR derived from the CG and MDRD formulas for most cancer patients, with less than 10% of patients expected to receive a different initial dose of chemotherapy. The MDRD formula may be a reasonable alternative to the CG formula for dosing of cancer drugs which are renally excreted or nephrotoxic. J Oncol Pharm Practice (2010) 16: 113—119.