Abstract P3-06-48: Pharmacogenetic dosing of epirubicin in FEC chemotherapy

Background:

Epirubicin dosing affects important clinical outcomes in breast cancer, with higher dose regimens improving efficacy but producing more myelosuppression. Epirubicin is metabolized by uridine glucuronosyltransferase 2B7 (UGT2B7). We previously reported relationships between UGT2B7’s promoter polymorphisms and epirubicin clearance and clinical outcomes in the (neo)adjuvant breast cancer setting; we identified a trend for increased grade 3/4 neutropenia but better efficacy outcomes in patients having at least one deficient allele (i.e. CT or CC) vs. patients who were wild type homozygotes. Patients homozygous for the deficient allele (CC) were at statistically significant increased risk for leucopenia compared to patients who were wild type homozygotes or heterozygotes. In this study we hypothesized patients with CT and TT genotypes would tolerate a higher epirubicin dose compared to CC genotype patients.

We designed this study to determine the safety of pharmacogenetic-guided epirubicin dosing for each UGT2B7 genotype.

Methods:

Female breast cancer patients with histologically confirmed non-metastatic invasive breast cancer scheduled to receive at least three cycles of FE100C in the (neo)adjuvant setting were enrolled into the study. Peripheral blood was analyzed for UGT2B7 genotype. Patients received standard dose IV FE100C during the first 21 day cycle. Based on genotype, epirubicin dosing was escalated in the 2nd and 3rd cycles.

Epirubicin Dose Escalation SchemeDose of Epirubicin per Cycle (mg/m2)CycleGenotype123CC100100100CT100115130TT100120140

Results:

To date 32 patients are evaluable for pharmacogenetic guided epirubicin dosing (8 CC genotypes, 14 CT genotypes and 10 TT genotypes). All 32 patients received epirubicin100 mg/m2 in cycle one and a single patient in each of the CC and CT genotypes experienced grade 3 febrile neutropenia and were not dose escalated. All other patients with CT and TT genotypes were dose escalated in cycle 2 and all but two patients in the CT and TT genotypes were dose escalated in cycle 3.

The incidence of febrile neutropenia was not dose dependent as all three genotypes had similar incidence in each cycle whereas leucopenia was genotype and dose dependent. The incidence of leukopenia increased in patients with CT and TT genotypes as their dose was increased and cycle 3 leukopenia rates were similar to patients with the CC genotype receiving standard dose epirubicin.

Conclusions:

Pharmacogenetic guided epirubicin dosing is well tolerated. This study is ongoing and updated data will be presented.

Citation Format: John R Mackey, Edith Pituskin, Ann Vlahadamis, Katia Tonkin, Karen King, Sanraj Basi, Maria Ho, Judith Meza-Junco, Anil Joy, Dick Au, Sambasivarao Damaraju, Michael B Sawyer. Pharmacogenetic dosing of epirubicin in FEC chemotherapy [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-48.

Urinary metabolomics of gastric cancer

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Background: Gastric cancer (GC) has 70-75% mortality, attributable to delayed diagnosis. There is no standard screening in North America. Metabolomics is a systems biology approach to measure low molecular weight chemicals (metabolites) in body fluids or tissues to provide a phenotypic “fingerprint” of disease etiology. In this preliminary study it was hypothesized that metabolic profiling of urine samples using 1H-NMR spectroscopy could discriminate between resectable gastric adenocarcinoma (GC), benign gastric disease (BN), and healthy (HE) patients (pts). Methods: Midstream urine samples were collected, processed, and biobanked at -80°C, from 30 BN, 30 HE and 16 of 29 GC pts visiting three Edmonton clinics from August 2013 – January 2014. Thirteen of 29 samples were retrieved from a 2009-13 GC biobank. Samples were matched on age, gender and BMI. Using a validated standard operating procedure each sample was analyzed using high resolution 1H-NMR spectroscopy. Resulting spectral traces were converted into annotated and quantified metabolite profiles of 58 metabolites. Univariate and multivariate statistical analysis uncovered a disease specific biomarker profile. Partial Least Squares Discriminant Analysis (PLS-DA) developed a GC vs. HE discriminative model. A Receiver Operator Characteristic (ROC) curve was constructed. Results: There was no significant difference in metabolite profiles between GC and BN pts. However, univariate analysis revealed 13 metabolites that differed significantly between GC and HE (p<0.05). Correlation analysis, followed by PLS-DA produced a discriminative model with an area under ROC curve of 0.996, such that for a specificity of 100% the corresponding sensitivity was 93%. Conclusions: GC pts have a distinct urinary metabolite profile compared to HE controls; however in this study metabolic profiling was unable to discriminate GC from BN pts. This was probably due to sample size and phenotypic heterogeneity of BN patients. This preliminary study shows clinical potential for metabolic profiling for early GC detection.

Abstract 4628: Acid suppression therapy impairs sunitinib efficacy in renal cell cancer (RCC)

Background: Sunitinib, a tyrosine kinase inhibitor (TKI), is standard therapy in metastatic RCC (mRCC). Developing side effects may be a marker of sufficient treatment doses. But as an oral drug, a potential issue is pH-dependent absorption. Recent evidence suggests TKI plasma levels can be altered by concomitant use of acid suppression therapy. Given gastroesophageal reflux disease (GERD) is a side effect of sunitinib and has high prevalence, this study aims to determine if coadministration of acid suppression therapy and sunitinib affected clinical outcomes in mRCC.

Methods: mRCC patients treated with sunitinib between two cancer centres from 2007 to 2013 were retrospectively reviewed. Patients were excluded if they received ≤ 1 week of treatment. Aside from demographics and histologic subtype, Memorial Sloan Kettering Cancer Center (MSKCC) and Heng prognostic scores were calculated. Sunitinib dose reductions were noted to divide patients into those that received 50 mg, 37.5 mg, or 25 mg. Patients were identified as receiving acid suppression if their pharmacy records included a proton pump inhibitor (PPI). Patients were considered taking these medications concomitantly if dates for PPI overlapped their sunitinib prescription by ≥ 20% of treatment duration. Progression free survival (PFS) and overall survival (OS) were primary endpoints.

Results: Of 383 mRCC patients identified, 379 were eligible for review. Median age was 62.7 years, 276 male, and 103 female. 286 had clear-cell histology and 93 non-clear cell. 47 patients were identified as continuously taking concomitant PPI, 146 intermittently, and 186 none at all. Median PFS for continuous, intermittent and no-PPI therapy groups were 4.3 months, 15.0 months, and 5.4 months, respectively (p&lt;0.0001). OS for the three groups were 9.3 months, 34.3 months, and 12.1 months, respectively (p&lt;0.0001). In multivariate analysis considering age, gender, histologic subtype, prior nephrectomy, and Heng score, Cox proportional hazards ratios for PFS and OS between continuous and no-PPI therapy groups were 2.08 (95% CI 1.43-3.05, p=0.0002) and 2.06 (95% CI 1.37-3.11, p=0.0006), respectively. Switching Heng for MSKCC score found similar hazards ratios of 2.06 (95% CI 1.41-3.01, p= 0.0002) and 2.09 (95% CI 1.39-3.14, p=0.0004), respectively. Our study found a trend to improved PFS and OS for those requiring a dose reduction (p=0.08). Effects of PPI therapy were still significant considering dose reductions.

Conclusion: This large population based study demonstrates sunitinib outcomes are affected by gastric acidity. Results lend further support that PPI therapy can alter TKI absorption; particularly as the intermittent PPI therapy group performed best suggesting that these patients were likely placed on PPI due to sunitinib toxicity. Consequently, they were effectively dose reduced using PPIs rather than decreasing administration dosage.

Citation Format: Michael P. Chu, Vincent Ha, Margaret Ngo, Sunita Ghosh, Carole R. Chambers, Michael B. Sawyer. Acid suppression therapy impairs sunitinib efficacy in renal cell cancer (RCC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4628. doi:10.1158/1538-7445.AM2014-4628

Potential role of metabolomics in diagnosis and surveillance of gastric cancer

Gastric cancer is one of the deadliest cancers worldwide, and is especially prevalent in Asian countries. With such high morbidity and mortality, early diagnosis is essential to achieving curative intent treatment and long term survival. Metabolomics is a new field of study that analyzes metabolites from biofluids and tissue samples. While metabolomics is still in its infancy, there are numerous potential applications in oncology, specifically early diagnosis. Only a few studies in the literature have examined metabolomics’ role in gastric cancer. Various fatty acid, carbohydrate, nucleic acid, and amino acid metabolites have been identified that distinguish gastric cancer from normal tissue and benign gastric disease. However, findings from these few studies are at times conflicting. Most studies demonstrate some relationship of cancer cells to the Warburg Effect, in that glycolysis predominates with conversion of pyruvate to lactate. This is one of the most consistent findings across the literature. There is less consistency in metabolomic signature with respect to nucleic acids, lipids and amino acids. In spite of this, metabolomics holds some promise for cancer surveillance but further studies are necessary to achieve consistency and validation before it can be widely employed as a clinical tool.

A phase I dose escalation trial of tremelimumab (CP-675,206) in combination with gemcitabine in chemotherapy-naive patients with metastatic pancreatic cancer

BACKGROUND

Tremelimumab (CP-675,206) is a fully human monoclonal antibody binding to cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) on T cells that stimulates the immune system by blocking the CTLA4-negative regulatory signal. Combination with standard chemotherapy may strengthen antitumor therapy. This is a phase Ib, multisite, open-label, nonrandomized dose escalation trial evaluating the safety, tolerability, and maximum tolerated dose (MTD) of tremelimumab combined with gemcitabine in patients with metastatic pancreatic cancer.

PATIENTS AND METHODS

Gemcitabine (1000 mg/m(2) on days 1, 8, and 15 of each 28-day cycles) was administrated with escalating doses of i.v. tremelimumab (6, 10, or 15 mg/kg) on day 1 of each 84-day cycle for a maximum of 4 cycles. The first 18 patients had an initial 4-week gemcitabine-only lead-in period. Dose-limiting toxicities (DLTs) related to tremelimumab were evaluated during the first 6 weeks after the first dose of tremelimumab.

RESULTS

From June 2008 to August 2011, 34 patients were enrolled and received at least one dose of tremelimumab. No DLTs related to tremelimumab were observed at any dose, even when the maximum dose established for tremelimumab (15 mg/kg) was used. Most frequent grade 3/4 toxicities were asthenia (11.8%) and nausea (8.8%). Only one patient had a serious drug-related event (diarrhea with dehydration). The median overall survival was 7.4 months (95% confidence interval 5.8-9.4 months). At the end of treatment, two patients achieved partial response. Both patients received tremelimumab 15-mg/kg group (n = 2/19, 10.5%).

CONCLUSION

Tremelimumab plus gemcitabine demonstrated a safety and tolerability profile, warranting further study in patients with metastatic pancreatic cancer.

CLINICALTRIALSGOV ID

NCT00556023.

Gastric Acid suppression is associated with decreased erlotinib efficacy in non-small-cell lung cancer

BACKGROUND

Erlotinib is a key therapy for advanced NSCLC. Concurrent AS therapy with TKIs might reduce TKI plasma levels. Because of gastroesophageal reflux disease prevalence, this retrospective analysis was undertaken to determine if coadministering erlotinib with AS therapy affected NSCLC outcomes.

PATIENTS AND METHODS

Records of advanced NSCLC patients who received erlotinib from 2007 to 2012 at a large, centralized, cancer institution were retrospectively reviewed. Pertinent demographic data were collected and concomitant AS treatment was defined as AS prescription dates overlapping with ≥ 20% of erlotinib treatment duration. Records of patients who received erlotinib for ≥ 1 week were analyzed for progression-free survival (PFS) and overall survival (OS).

RESULTS

Stage IIIB/IV NSCLC patients (n = 544) were identified and 507 had adequate data for review. The median age was 64 years and 272 were female. Adenocarcinoma (n = 318; 64%) and squamous (n = 106; 21%) were predominant subtypes; 124 patients received concomitant AS therapy. In this unselected population, median PFS and OS in AS versus no AS groups were 1.4 versus 2.3 months (P < .001) and 12.9 versus 16.8 months (P = .003), respectively. Factoring sex, subtype, and performance status in multivariate Cox proportional hazards ratios for PFS and OS between AS and no AS groups were 1.83 (95% confidence interval [CI], 1.48-2.25) and 1.37 (95% CI, 1.11-1.69), respectively.

CONCLUSION

This large population-based study suggests erlotinib efficacy might be linked with gastric pH and OS could be adversely affected. To our knowledge, this is the first study demonstrating a possible negative clinical effect of coadministration of erlotinib with AS therapy. Further prospective investigation is warranted.

The association between body composition and toxicities from the combination of Doxil and trabectedin in patients with advanced relapsed ovarian cancer

Emerging research suggests that body composition can predict toxicity of certain chemotherapeutic agents. We used data from a clinical study to investigate associations between body composition and combined DOXIL (pegylated liposomal doxorubicin; PLD) and trabectedin (Yondelis) treatment, an effective treatment for ovarian cancer that shows high interpatient variation in toxicity profile. Patients (n = 74) participating in a phase III randomized trial of relapsed advanced ovarian cancer receiving PLD (30 mg/m2) and trabectedin (1.1 mg/m2) were included. Muscle tissue was measured by analysis of computerized tomography images, and an extrapolation of muscle and adipose tissue to lean body mass (LBM) and fat mass (FM) were employed. Toxicity profile after cycle 1 was used and graded according to the National Cancer Institute Common Toxicity Criteria (version 3). Patients presented with a wide range of body composition. In overweight and obese patients (body mass index (BMI) ≥ 25 kg/m2, n = 48) toxicity was more prevalent in those with lower BMI (p = 0.028) and a lower FM (n = 43, p = 0.034). Although LBM alone was not predictive of toxicity, a lower FM/LBM ratio was the most powerful variable associated with toxicity (p = 0.006). A different pattern emerged among normal weight patients (n = 26) where toxicity was rare among patients with smaller BMI (<21 kg/m2). A clear association between both FM and LBM (primarily driven by FM) in explaining PLD plus trabectedin toxicity emerged, but only in individuals with excess body weight, with a lower ratio predicting higher exposure and risk for toxicity.

Severe muscle depletion predicts postoperative length of stay but is not associated with survival after liver transplantation

Muscle depletion or sarcopenia is associated with increased mortality in patients with cirrhosis; how it affects mortality after liver transplantation requires further study. In this study, we aimed to establish whether sarcopenia predicts increased morbidity or mortality after liver transplantation. We analyzed 248 patients with cirrhosis who had a computed tomography (CT) scan including the third lumbar vertebra before liver transplantation. Data were recovered from medical charts, the skeletal muscle cross-sectional area was measured with CT, and sarcopenia was defined with previously published sex- and body mass index-specific cutoffs. One hundred sixty-nine patients (68%) were male, and the mean age at transplantation was 55 ± 1 years. The etiologies of cirrhosis were hepatitis C virus (51%), alcohol (19%), autoimmune liver diseases (15%), hepatitis B virus (8%), and other etiologies (7%). Sarcopenia was present in 112 patients (45%), and it was more frequent in males (P = 0.002), patients with ascites (P = 0.02), and patients with higher bilirubin levels (P = 0.05), creatinine levels (P = 0.02), international normalized ratios (P = 0.04), Child-Pugh scores (P = 0.002), and Model for End-Stage Liver Disease scores (P = 0.002). The median survival period after liver transplantation was 117 ± 17 months for sarcopenic patients and 146 ± 20 months for nonsarcopenic patients (P = 0.4). Sarcopenic patients had longer hospital stays (40 ± 4 versus 25 ± 3 days; P = 0.005) and a higher frequency of bacterial infections within the first 90 days after liver transplantation (26% versus 15%, P = 0.04) in comparison with nonsarcopenic patients. In conclusion, sarcopenia is one of the most common complications in patients with cirrhosis and is predictive of longer hospital stays and a higher risk of perioperative bacterial infections after liver transplantation, but it is not associated with increased mortality.

Does gastric acid suppression affect sunitinib efficacy in patients with advanced or metastatic renal cell cancer?

Introduction:

Renal cell cancer is a chemotherapy-insensitive cancer treated by vascular endothelial growth factor receptor antagonists. Recently, a question has arisen on whether there is an interaction between tyrosine kinase inhibitors, such as sunitinib, and acid suppressing agents.

Methods:

A retrospective chart review was conducted for patients at two tertiary care centers who received sunitinib between 1 January 2006 and 31 March 2013. Using electronic systems and a province-wide electronic health records database, medication dispensing records were obtained. A univariate Cox’s proportional hazard model determined if acid suppression had effects on progression-free survival and overall survival.

Results:

Of 383 patient charts reviewed, 231 were included in the study. Patients on intermittent acid suppression, lost to follow-up or received sunitinib for less than one week were excluded from the study. The median age of the study population was 65. Patients who received no acid suppression (n = 186) had a median progression-free survival of 23.6 weeks (95% CI, 19.0–31.9 weeks) and patients who received continuous acid suppression (n = 45) had a median progression-free survival of 18.9 weeks (95% CI, 11.0–23.7  p = 0.04). A median overall survival of 62.4 weeks (95% CI, 42.0–82.7 weeks) was observed in the group with no acid suppression, while a median overall survival of 40.9 weeks (95% CI, 26.1–74.4 weeks) was observed in the continuous acid suppression group ( p = 0.02).

Conclusion:

There was a significant difference in progression-free survival and overall survival between the acid suppressed and no acid suppression groups. Further research is required to confirm this potential interaction.

Carcinoma of unknown primary in the inguinal lymph node region of squamous cell origin: A case series

PURPOSE

Cancer of unknown primary (CUP) of the inguinal region is a rare clinical entity that accounts for 1%-3 % of all CUPs. Of the inguinal lymph node region CUPs, about 10%-15% are of squamous cell origin. This study presents a case series of CUP of the inguinal region of squamous cell origin treated in our institution and review of the outcome.

METHODS AND MATERIALS

We have identified 9 patients treated during the period of 1990-2010. All patients were treated radically with chemoradiation. Regimens used were 5-fluorouracil (5-FU)/cisplatin combination (n = 8) or 5-FU/mitomycin-C (n = 1) regimen. Tumor doses were 5400 cGy (n = 7), 5500 cGy (n = 1), and 5040 cGy (n = 1).

RESULTS

The median duration of follow-up was 56 months (range, 10-76 months) for the whole group. There were no deaths or local or distant recurrences reported till the last recorded date of follow-up.

CONCLUSIONS

Our retrospective data showed significant long-term disease control for patients with localized inguinal region CUP of squamous cell origin who received concurrent chemoradiation.

Comparative in vitro evaluation of transportability and toxicity of capecitabine and its metabolites in cells derived from normal human kidney and renal cancers

The goal of this study was to understand roles of nucleoside and nucleobase transport processes in capecitabine pharmacology in cells derived from human renal proximal tubule cells (hRPTCs) and three human renal cell carcinoma (RCC) cell lines, A498, A704, and Caki-1. Human equilibrative nucleoside transporters 1 and 2 (hENT1 and hENT2) mediated activities and a sodium-independent nucleobase activity were present in hRPTCs. In hRPTCs, uptake of 5′-deoxy-5-fluorouridine (DFUR), a nucleoside metabolite of capecitabine, was pH dependent with highest uptake seen at pH 6.0. In RCC cell lines, hENT1 was the major nucleoside transporter. Nucleobase transport activity was variable among the three RCC cell lines, with Caki-1 showing the highest and A498 showing the lowest activities. Treatment of RCC cell lines with interferon alpha (IFN-α) increased thymidine phosphorylase levels and prior treatment of RCC cell lines with IFN-α followed by 5-FU or DFUR resulted in enhanced sensitivity of all cell lines to 5-FU and two of three cell lines to DFUR. We report for the first time a nucleobase transport activity in hRPTCs and RCC cell lines. In addition, our in vitro cytotoxicity results showed that RCC cell lines differed in their response to 5-FU and DFUR and prior treatment with IFN-α potentiated cytotoxic response to metabolites of capecitabine.

Dietary patterns of patients with advanced lung or colorectal cancer

The purpose of this study was to identify dietary patterns among patients with advanced cancer. Differences between cancer groups are described, and food groups contributing higher proportions to overall caloric intake are identified. Patients with advanced cancer (n=51) were recruited from a regional cancer centre and completed a three-day dietary record. Food items were categorized according to macronutrient content. After adjustment for body weight, substantial variation in energy intake was observed (range: 13.7 to 55.4 kcal/kg/day). For 49% of patients, protein intake was below recommendations. Overall, patients consumed the largest proportion of their calories from meat (16%), other foods (11%), dessert (9%), fruit (9%), white bread (7%), and milk (7%). Only 5% of patients consumed meal replacement supplements. The results of this descriptive study provide important insights into the dietary habits of patients with advanced cancer. These insights could be translated into the development of effective recommendations for maintaining or improving health and quality of life.

Erlotinib, gefitinib, and vandetanib inhibit human nucleoside transporters and protect cancer cells from gemcitabine cytotoxicity

PURPOSE

Combinations of tyrosine kinase inhibitors (TKI) with gemcitabine have been attempted with little added benefit to patients. We hypothesized that TKIs designed to bind to ATP-binding pockets of growth factor receptors also bind to transporter proteins that recognize nucleosides.

EXPERIMENTAL DESIGN

TKI inhibition of uridine transport was studied with recombinant human (h) equilibrative (E) and concentrative (C) nucleoside transporters (hENT, hCNT) produced individually in yeast. TKIs effects on uridine transport, gemcitabine accumulation, regulation of hENT1 activity, and cell viability in the presence or absence of gemcitabine were evaluated in human pancreatic and lung cancer cell lines.

RESULTS

Erlotinib, gefitinib and vandetanib inhibited [(3)H]uridine transport in yeast and [(3)H]uridine and [(3)H]gemcitabine uptake in the four cell lines. Treatment of cell lines with erlotinib, gefitinib, or vandetanib for 24 hours reduced hENT1 activity which was reversed by subsequent incubation in drug-free media for 24 hours. Greater cytotoxicity was observed when gemcitabine was administered before erlotinib, gefitinib, or vandetanib than when administered together and synergy, evaluated using the CalcuSyn Software, was observed in three cell lines resulting in combination indices under 0.6 at 50% reduction of cell growth.

CONCLUSIONS

Vandetanib inhibited hENT1, hENT2, hCNT1, hCNT2, and hCNT3, whereas erlotinib inhibited hENT1 and hCNT3 and gefitinib inhibited hENT1 and hCNT1. The potential for reduced accumulation of nucleoside chemotherapy drugs in tumor tissues due to inhibition of hENTs and/or hCNTs by TKIs indicates that pharmacokinetic properties of these agents must be considered when scheduling TKIs and nucleoside chemotherapy in combination.

Central tenet of cancer cachexia therapy: do patients with advanced cancer have exploitable anabolic potential?

BACKGROUND

Skeletal muscle wasting is considered the central feature of cachexia, but the potential for skeletal muscle anabolism in patients with advanced cancer is unproven.

OBJECTIVE

We investigated the clinical course of skeletal muscle wasting in advanced cancer and the window of possible muscle anabolism.

DESIGN

We conducted a quantitative analysis of computed tomography (CT) images for the loss and gain of muscle in population-based cohorts of advanced cancer patients (lung, colorectal, and pancreas cancer and cholangiocarcinoma) in a longitudinal observational study.

RESULTS

Advanced-cancer patients (n = 368; median survival: 196 d) had a total of 1279 CT images over the course of their disease. With consideration of all time points, muscle loss occurred in 39% of intervals between any 2 scans. However, the overall frequency of muscle gain was 15.4%, and muscle was stable in 45.6% of intervals between any 2 scans, which made the maintenance or gain of muscle the predominant behavior. Multinomial logistic regression revealed that being within 90 d (compared with >90 d) from death was the principal risk factor for muscle loss (OR: 2.67; 95% CI: 1.45, 4.94; P = 0.002), and muscle gain was correspondingly less likely (OR: 0.37; 95% CI: 0.20, 0.69; P = 0.002) at this time. Sex, age, BMI, and tumor group were not significant predictors of muscle loss or gain.

CONCLUSIONS

A window of anabolic potential exists at defined early phases of the disease trajectory (>90 d survival), creating an opportunity for nutritional intervention to stop or reverse cachexia. Cancer patients within 90 d of death have a low likelihood of anabolic potential.

Assessment of nutritional status in cancer--the relationship between body composition and pharmacokinetics

Several nutritional assessment tools have been used in oncology settings to monitor nutritional status and its associated prognostic significance. Body composition is fundamental for the assessment of nutritional status. Recently, the use of accurate and precise body composition tools has significantly added to the value of nutritional assessment in this clinical setting. Computerized tomography (CT) is an example of a technique which provides state-of-the-art assessment of body composition. With use of CT images, a great variability in body composition of cancer patients has been identified even in people with identical body weight or body mass index. Severe muscle depletion (sarcopenia) has emerged as a prevalent body composition phenotype which is predictive of poor functional status, shorter time to tumor progression, shorter survival, and higher incidence of dose-limiting toxicity. Variability in body composition of cancer patients may be a source of disparities in the metabolism of cytotoxic agents. Future clinical trials investigating dose reductions in patients with sarcopenia and dose-escalating studies based on pre-treatment body composition assessment have the potential to alter cancer treatment paradigms.

Cellular influx, efflux, and anabolism of 3-carboranyl thymidine analogs: potential boron delivery agents for neutron capture therapy

3-[5-{2-(2,3-Dihydroxyprop-1-yl)-o-carboran-1-yl}pentan-1-yl]thymidine (N5-2OH) is a first generation 3-carboranyl thymidine analog (3CTA) that has been intensively studied as a boron-10 ((10)B) delivery agent for neutron capture therapy (NCT). N5-2OH is an excellent substrate of thymidine kinase 1 and its favorable biodistribution profile in rodents led to successful preclinical NCT of rats bearing intracerebral RG2 glioma. The present study explored cellular influx and efflux mechanisms of N5-2OH, as well as its intracellular anabolism beyond the monophosphate level. N5-2OH entered cultured human CCRF-CEM cells via passive diffusion, whereas the multidrug resistance-associated protein 4 appeared to be a major mediator of N5-2OH monophosphate efflux. N5-2OH was effectively monophosphorylated in cultured murine L929 [thymidine kinase 1 (TK1(+))] cells whereas formation of N5-2OH monophosphate was markedly lower in L929 (TK1(-)) cell variants. Further metabolism to the di- and triphosphate forms was not observed in any of the cell lines. Regardless of monophosphorylation, parental N5-2OH was the major intracellular component in both TK1(+) and TK1(-) cells. Phosphate transfer experiments with enzyme preparations showed that N5-2OH monophosphate, as well as the monophosphate of a second 3-carboranyl thymidine analog [3-[5-(o-carboran-1-yl)pentan-1-yl]thymidine (N5)], were not substrates of thymidine monophosphate kinase. Surprisingly, N5-diphosphate was phosphorylated by nucleoside diphosphate kinase although N5-triphosphate apparently was not a substrate of DNA polymerase. Our results provide valuable information on the cellular metabolism and pharmacokinetic profile of 3-carboranyl thymidine analogs.

Development of a new equation to estimate GFR in cancer patients

e13503

Background: Renal function affects chemotherapy pharmacokinetics. Carboplatin dosing by Calvert’s formula is more pharmacologically rational, but requires an accurate glomerular filtration rate (GFR). Calvert argues that this requires measuring GFR (mGFR) instead of an estimated GFR (eGFR). Considering skeletal muscle is the major source for creatinine, this study looks to develop a new eGFR equation in cancer patients using lean body mass (LBM). Methods: We prospectively followed 22 stage IV cancer patients (10 female, 12 male; median age 69) who received carboplatin. mGFR by 24 hr creatinine clearance was compared to eGFR by Wright, Cockcroft-Gault (CG), CKD-EPI, MDRD and CT-determined LBM (eGFR = [Muscle Surface Area X 42]/CR). Simulated carboplatin dosing with each eGFR was then compared retrospectively in 100 Non-Small Cell Lung Cancer (NSCLC) patients for accuracy. Results: MDRD, CG, and Wright equations correlated variably with mGFR (R2 0.47, 0.57, and 0.69 respectively). Conversely, mGFR strongly correlated with LBM eGFR (R2 0.84). The Table compares eGFR calculations with mean residual error. In simulated carboplatin dosing of 100 stage IV NSCLC patients using LBM and CG eGFR, the mean residual error of the CG-determined carboplatin dose was 10% (0.5% min, max 39.7%, median 9.3%), assuming the LBM eGFR was better at estimating eGFR. This means that in approximately half of patients, carboplatin dose may be incorrect by CG if the new LBM eGFR method is truly more accurate. Conclusions: We propose a new formula for eGFR in cancer patients that appears superior to current formulas and may have implications for chemotherapy efficacy and toxicity. Studies to validate this formula are under way. [Table: see text]

Effects of gefitinib and vandetanib on human equilibrative nucleoside transporter 1 and on gemcitabine cytotoxicity

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Background: Combination chemotherapy with tyrosine kinase inhibitors (TKIs) and gemcitabine has been attempted with little added benefit to patients. We hypothesized that TKIs that were designed to bind to ATP pockets of growth factor tyrosine kinases also bind to proteins that recognize nucleosides, thereby potentially interfering with gemcitabine pharmacology. Methods: Interaction of TKIs with human nucleoside transporters (NTs) was studied using recombinant NTs produced in yeast. Effects of TKIs on uridine transport, gemcitabine transport and accumulation, regulation of NT activity and cytotoxicity with and without gemcitabine were evaluated in human A549 lung cancer cells. Results: In yeast, vandetanib inhibited two equilibrative NTs (hENT1, hENT2) and three concentrative NTs (hCNT1, hCNT2, hCNT3) with the greatest inhibition seen with hENT1 whereas gefitinib strongly inhibited hENT1 and hCNT1 only. In A549 cells, which possess major hENT1 and minor hENT2 activities, [3H]uridine uptake was inhibited by vandetanib and gefitinib with IC50 values of 16 ± 4 and 5 ± 0.3µM, respectively. Both TKIs also inhibited [3H]gemcitabine transport and accumulation in A549 cells. hENT1 protein levels were decreased during exposures to vandetanib or gefitinib for 24 hours, and cytotoxicity was greatest when gemcitabine was given prior to vandetanib or gefitinib. Conclusions: Vandetanib and gefitinib inhibited human NTs, especially hENT1, resulting in reduced intracellular gemcitabine accumulation. Gefitinib or vandetanib levels achieved in plasma and tumor tissues are sufficient to inhibit hENT1 activity. Because TKIs can block uptake of nucleoside chemotherapy drugs in cultured cancer cells, attention must be paid to TKIs and nucleoside pharmacokinetic properties when scheduling TKIs and nucleoside chemotherapy.

Phase III randomized, placebo-controlled study of cetuximab plus brivanib alaninate versus cetuximab plus placebo in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal carcinoma: the NCIC Clinical Trials Group and AGITG CO.20 Trial

PURPOSE

The antiepidermal growth factor receptor monoclonal antibody cetuximab has improved survival in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer. The addition of brivanib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor and fibroblast growth factor receptor, to cetuximab has shown encouraging early clinical activity.

PATIENTS AND METHODS

Patients with metastatic colorectal cancer previously treated with combination chemotherapy were randomly assigned 1:1 to receive cetuximab 400 mg/m(2) intravenous loading dose followed by weekly maintenance of 250 mg/m(2) plus either brivanib 800 mg orally daily (arm A) or placebo (arm B). The primary end point was overall survival (OS).

RESULTS

A total of 750 patients were randomly assigned (376 in arm A and 374 in arm B). Median OS in the intent-to-treat population was 8.8 months in arm A and 8.1 months in arm B (hazard ratio [HR], 0.88; 95% CI, 0.74 to 1.03; P = .12). Median progression-free survival (PFS) was 5.0 months in arm A and 3.4 months in arm B (HR, 0.72; 95% CI, 0.62 to 0.84; P < .001). Partial responses observed (13.6% v 7.2%; P = .004) were higher in arm A. Incidence of any grade ≥ 3 adverse events was 78% in arm A and 53% in arm B. Fewer patients received ≥ 90% dose-intensity of both cetuximab (57% v 83%) and brivanib/placebo (48% v 87%) in arm A versus arm B, respectively.

CONCLUSION

Despite positive effects on PFS and objective response, cetuximab plus brivanib increased toxicity and did not significantly improve OS in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer.

Cancer Cachexia in the Age of Obesity: Skeletal Muscle Depletion Is a Powerful Prognostic Factor, Independent of Body Mass Index

Purpose

Emerging evidence suggests muscle depletion predicts survival of patients with cancer.

Patients and Methods

At a cancer center in Alberta, Canada, consecutive patients with cancer (lung or GI; N = 1,473) were assessed at presentation for weight loss history, lumbar skeletal muscle index, and mean muscle attenuation (Hounsfield units) by computed tomography (CT). Univariate and multivariate analyses were conducted. Concordance (c) statistics were used to test predictive accuracy of survival models.

Results

Body mass index (BMI) distribution was 17% obese, 35% overweight, 36% normal weight, and 12% underweight. Patients in all BMI categories varied widely in weight loss, muscle index, and muscle attenuation. Thresholds defining associations between these three variables and survival were determined using optimal stratification. High weight loss, low muscle index, and low muscle attenuation were independently prognostic of survival. A survival model containing conventional covariates (cancer diagnosis, stage, age, performance status) gave a c statistic of 0.73 (95% CI, 0.67 to 0.79), whereas a model ignoring conventional variables and including only BMI, weight loss, muscle index, and muscle attenuation gave a c statistic of 0.92 (95% CI, 0.88 to 0.95; P < .001). Patients who possessed all three of these poor prognostic variables survived 8.4 months (95% CI, 6.5 to 10.3), regardless of whether they presented as obese, overweight, normal weight, or underweight, in contrast to patients who had none of these features, who survived 28.4 months (95% CI, 24.2 to 32.6; P < .001).

Conclusion

CT images reveal otherwise occult muscle depletion. Patients with cancer who are cachexic by the conventional criterion (involuntary weight loss) and by two additional criteria (muscle depletion and low muscle attenuation) share a poor prognosis, regardless of overall body weight.