Effects of gender on capecitabine toxicity in colorectal cancer

BACKGROUND

Capecitabine is a highly water soluble prodrug of 5-fluorouracil that is dosed by patient body surface area. Body surface area dosing makes no allowances for differences in body composition. There is mounting evidence that lean body mass is a better predictor of toxicity than body surface area for drugs which distribute into the lean compartment. Because women, on average, have lower lean body mass than men, we expect that women would experience a higher incidence of toxicity than men when body surface area dosing is used.

OBJECTIVE

To determine whether female colorectal cancer patients experienced a higher incidence of dose-limiting toxicity than men when treated with adjuvant capecitabine.

METHODS

We conducted a retrospective chart review of colorectal cancer patients treated with adjuvant capecitabine at our institute between 2008 and 2012. Patients receiving capecitabine were identified from the pharmacy dispensing database and then screened for inclusion. Dosing and toxicity information were gathered and dose-limiting toxicity incidence (defined as a composite endpoint of dose delay, dose reduction, or discontinuation of therapy) was compared between males and females using the chi-square test. Binary logistic regression analysis was then performed to account for differences between male and female populations.

RESULTS

A total of 299 patients (163 males, 136 females) met inclusion criteria. Females had a significantly higher dose-limiting toxicity incidence than males (67.7 vs. 52.2%, p = 0.007). Relationships between gender and dose-limiting toxicity incidence remained significant after logistic regression analysis (OR: 2.04; 95% CI: 1.23-3.36).

CONCLUSION

Female colorectal cancer patients experience a higher dose-limiting toxicity incidence than male patients when given adjuvant capecitabine dosed according to body surface area.

Critical appraisal of trastuzumab in treatment of advanced stomach cancer

Advanced or metastatic gastric cancer constitutes the majority of patients in clinical practice. In North America, about 70% of cases are advanced or metastatic when diagnosed, which is higher than the 50% reported in Japan. This difference in presentation is reflected in 5-year overall survival, which is about 20% in North America and 40%-60% in Japan. Despite numerous efforts of randomized studies on advanced gastric cancer, no globally accepted standard regimen has yet been established. Systemic chemotherapy provides palliation and prolongs survival, but the prognosis remains poor. Several monotherapies and combined regimens are currently available and vary around the world. Additionally, several molecular targeting agents are under evaluation in international randomized studies. Human epidermal growth factor receptor-2 (HER-2) is overexpressed or amplified in approximately 22% of patients with gastric cancer. Trastuzumab, a recombinant humanized anti-HER-2 monoclonal antibody, is the first biological therapy that has showed a survival improvement by nearly three months (reduced risk of death by 26%). Therefore, trastuzumab in combination with cisplatin is a reasonable treatment option for patients with advanced gastric cancer who are HER-2 positive. This paper will focus on trastuzumab, its chemical and pharmacological characteristics, and the relevant efficacy, safety, and tolerability studies.

Metastatic gastric cancer - focus on targeted therapies

Gastric cancer (GC) is currently the second leading cause of cancer death worldwide; unfortunately, most patients will present with locally advanced or metastatic disease. Despite recent progress in diagnosis, surgery, chemotherapy, and radiotherapy, prognosis remains poor. A better understanding of GC biology and signaling pathways is expected to improve GC therapy, and the integration of targeted therapies has recently become possible and appears to be promising. This article focuses on anti-Her-2 therapy, specifically trastuzumab, as well as other epidermal growth factor receptor antagonists such as cetuximab, panitumub, matuzumab, nimotzumab, gefitinib, and erlotinib. Additionally, drugs that target angiogenesis pathways are also under investigation, particulary bevacizumab, ramucirumab, sorafenib, sunitinib, and cediranib. Other targeted agents in preclinical or early clinical development include mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors, anti-insulin-like growth factor, anti-heat shock proteins, and small molecules targeting Hedgehog signaling.

Multitargeted kinase inhibitors imatinib, sorafenib and sunitinib perturb energy metabolism and cause cytotoxicity to cultured C2C12 skeletal muscle derived myotubes

Tyrosine kinase inhibitors (TKIs) have advanced cancer treatment and prognosis but have also resulted in adverse effects such as fatigue, diarrhea, hypothyroidism, and other toxicities. We investigated TKI effects on skeletal muscle as a possible explanation of TKI induced fatigue. Changes in mitochondrial function due to inhibition of oxidative phosphorylation complexes, generation of superoxides, and inhibition of key transporters involved in uptake of glucose and/or nucleosides may result in alteration of energy metabolism and/or mitochondrial function. We investigated effects of imatinib, sorafenib and sunitinib on these processes in cultured C2C12 murine skeletal muscle cells. Imatinib, sorafenib and sunitinib were cytotoxic to C2C12 cells with IC₅₀ values of 20, 8 and 8 µM, respectively. Imatinib stimulated glucose uptake and inhibited complex V activity by 35% at 50 µM. Sorafenib inhibited complex II/III and V with IC₅₀ values of 32 and 28 µM, respectively. Sorafenib caused activation of caspase 3/7 and depolarization of mitochondrial membranes occurred very rapidly with complete loss at 5-10 µM. Sunitinib inhibited Complex I with an IC₅₀ value of 38 µM and caused ATP depletion, caspase 3/7 activation, an increase in reactive oxygen species (ROS), and decreased nucleoside and glucose uptake. In conclusion, imatinib, sunitinib and sorafenib caused changes in mitochondrial complex activities, glucose and nucleoside uptake leading to decreased energy production and mitochondrial function in a skeletal muscle cell model, suggesting that these changes may play a role in fatigue, one of the most common adverse effects of TKIs.

Development and validation of a bedside score to predict early death in cancer of unknown primary patients

BACKGROUND

We have investigated predictors of 90-day-mortality in a large cohort of non-specific cancer of unknown primary patients.

METHODS

Predictors have been identified by univariate and then logistic regression analysis in a single-center cohort comprising 429 patients (development cohort). We identified four predictors that produced a predictive score that has been applied to an independent multi-institutional cohort of 409 patients (validation cohort). The score was the sum of predictors for each patient (0 to 4).

RESULTS

The 90-day-mortality-rate was 33 and 26% in both cohorts. Multivariate analysis has identified 4 predictors for 90-day-mortality: performance status>1 (OR = 3.03, p = 0.001), at least one co-morbidity requiring treatment (OR = 2.68, p = 0.004), LDH>1.5 x the upper limit of normal (OR = 2.88, p = 0.007) and low albumin or protein levels (OR = 3.05, p = 0.007). In the development cohort, 90-day-mortality-rates were 12.5%, 32% and 64% when the score was [0-1], 2 and [3]-[4], respectively. In the validation cohort, risks were 13%, 25% and 62% according to the same score values.

CONCLUSIONS

We have validated a score that is easily calculated at the beside that estimates the 90-days mortality rate in non-specific CUP patients. This could be helpful to identify patients who would be better served with palliative care rather than aggressive chemotherapy.

Accuracy of Resting Energy Expenditure Predictive Equations in Patients With Cancer

BACKGROUND

Our purpose was to assess the accuracy of resting energy expenditure (REE) equations in patients with newly diagnosed stage I-IV non-small cell lung, rectal, colon, renal, or pancreatic cancer.

METHODS

In this cross-sectional study, REE was measured using indirect calorimetry and compared with 23 equations. Agreement between measured and predicted REE was assessed via paired t-tests, Bland-Altman analysis, and percent of estimations ≤ 10% of measured values. Accuracy was measured among subgroups of body mass index (BMI), stage (I-III vs IV), and cancer type (lung, rectal, and colon) categories. Fat mass (FM) and fat-free mass (FFM) were assessed using dual x-ray absorptiometry.

RESULTS

Among 125 patients, most had lung, colon, or rectal cancer (92%, BMI: 27.5 ± 5.6 kg/m² , age: 61 ± 11 years, REE: 1629 ± 321 kcal/d). Thirteen (56.5%) equations yielded REE values different than measured (P < 0.05). Limits of agreement were wide for all equations, with Mifflin-St. Jeor equation having the smallest limits of agreement, -21.7% to 11.3% (-394 to 203 kcal/d). Equations with FFM were not more accurate except for one equation (Huang with body composition; bias, limits of agreement: -0.3 ± 11.3% vs without body composition: 2.3 ± 10.1%, P < 0.001). Bias in body composition equations was consistently positively correlated with age and frequently negatively correlated with FM. Bias and limits of agreement were similar among subgroups of patients.

CONCLUSION

REE cannot be accurately predicted on an individual level, and bias relates to age and FM.

Mass spectrometry study of hemoglobin-oxaliplatin complexes in colorectal cancer patients and potential association with chemotherapeutic responses

Oxaliplatin is the most active platinum (Pt)-containing anticancer drug for the treatment of advanced colorectal cancer. We report here the study of potential association of the levels of oxaliplatin-protein complexes in 19 cancer patients with treatment efficacy using size-exclusion high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS) and nanoelectrospray ionization mass spectrometry (nanoESI-MS) techniques. Blood samples from 19 colorectal cancer patients were collected at 1 and 48 h after the first infusion of oxaliplatin. HPLC/ICPMS quantification of the oxaliplatin-protein complexes showed that the levels of Pt-protein complexes in plasma samples at 48 h were reduced by approximately 50% compared to those at 1 h, whereas those in hemolysates did not change significantly. The concentrations of hemoglobin (Hb)-oxaliplatin complexes determined by HPLC/ICPMS ranged from 3.1 to 8.7 microM. NanoESI-MS analysis of the patient hemolysates showed three distinct mass spectral profiles of the Hb-oxaliplatin complexes: (1) 1:1, (2) 1:1 with 1:2, and (3) multiple complexes of 1:1, 1:2, 1:3, and 1:4, corresponding to the Hb-oxaliplatin complex concentrations determined by HPLC/ICPMS. Potential association of variables including Hb-oxaliplatin complex concentrations with time to progress as the treatment efficacy indicator was analyzed using the Cox model. Multivariate analysis of the potential predictors showed that the statistically significant variables were Hb-oxaliplatin complex concentration (p = 0.02), performance status (p = 0.02), baseline neutrophil count (p = 0.05), and the site of the primary cancer (colon vs. rectal, p = 0.01). The hazard ratio for the concentration of the Hb-oxaliplatin complexes was 2.4, suggesting that the risk of cancer progression significantly increased with increasing of Hb-oxaliplatin complexes in patients. These results demonstrate that the level of the Hb-oxaliplatin complexes in erythrocytes is a potential biomarker for indicating inter-patient variations in oxaliplatin treatment efficacy.

Selective Inhibition of Human Equilibrative and Concentrative Nucleoside Transporters by BCR-ABL Kinase Inhibitors: IDENTIFICATION OF KEY hENT1 AMINO ACID RESIDUES FOR INTERACTION WITH BCR-ABL KINASE INHIBITORS

Human nucleoside transporters (hNTs) mediate cellular influx of anticancer nucleoside drugs, including cytarabine, cladribine, and fludarabine. BCR-ABL tyrosine kinase inhibitors (TKIs) imatinib and dasatinib inhibit fludarabine and cytarabine uptake. We assessed interactions of bosutinib, dasatinib, imatinib, nilotinib, and ponatinib with recombinant hNTs (hENT1, 2; hCNT1, -2, and -3) produced individually in yeast Saccharomyces cerevisiae Nilotinib inhibited hENT1-mediated uridine transport most potently (IC50 value, 0.7 μm) followed by ponatinib > bosutinib > dasatinib > imatinib. Imatinib inhibited hCNT2 with an IC50 value of 2.3 μm Ponatinib inhibited all five hNTs with the greatest effect seen for hENT1 (IC50 value, 9 μm). TKIs inhibited [(3)H]uridine uptake in a competitive manner. Studies in yeast with mutants at two amino acid residues of hENT1 (L442I, L442T, M33A, M33A/L442I) previously shown to be involved in uridine and dipyridamole binding, suggested that BCR-ABL TKIs interacted with Met(33) (TM1) and Leu(442) (TM11) residues of hENT1. In cultured human CEM lymphoblastoid cells, which possess a single hNT type (hENT1), accumulation of [(3)H]cytarabine, [(3)H]cladribine, or [(3)H]fludarabine was reduced by each of the five TKIs, and also caused a reduction in cell surface expression of hENT1 protein. In conclusion, BCR-ABL TKIs variously inhibit five different hNTs, cause a decrease in cell surface hENT1 expression, and decrease uridine accumulation when presented together with uridine or when given before uridine. In experiments with mutant hENT1, we showed for the first time interaction of Met(33) (involved in dipyridamole binding) with BCR-ABL inhibitors and reduced interaction with M33A mutant hENT1.

Characterization of binding of folates and antifolates to brush-border membrane vesicles isolated from human kidney

Antifolates such as methotrexate, raltitrexed, and pemetrexed are among the most effective and widely used anticancer drugs. The antifolates are also among the most unpredictable of anticancer drugs with respect to pharmacokinetics and toxicity. In this study, we assessed the binding of folates and antifolates to the folate receptors (FRs) of human proximal tubules and the effects of pH on binding. Binding of [(3)H]folic acid was pH-dependent, with maximal binding seen at pH 6. Equilibrium binding experiments with [(3)H]folic acid showed that K(d) values were unaffected, and B(max) values increased as the pH was decreased from 8.0 to 6.0. Increasing the osmolarity at pH 6.0 had no effect on intravesicular content, confirming that increased site-specific binding caused the observed changes in B(max) values. Enzymatic cleavage of glycosyl-phosphatidylinositol linkages abolished binding of [(3)H]folic acid to brush-border membrane vesicles, suggesting that [(3)H]folic acid was bound to FRs. In concentration-effect experiments conducted at different pH values, the antifolates raltitrexed and (2S)-2-[o-fluoro-p-[N-(2,7-dimethyl-4-oxo-3,4-dihydroquinazolin-6-yl-methyl)-N-(prop-2-ynyl)amino]benzamido]-4-(tetrazol-5-yl) butyric acid (ZD9331) bound more tightly as pH increased from 6.0 to 8.0, whereas binding of 10-propargyl-5,8-dideazafolic acid (CB3717) was unchanged. The results obtained when K(i) values were converted to binding energies suggested that binding of some, but not all, antifolates and folates to FRs was pH-dependent, further indicating roles of luminal pH in renal reabsorption or secretion processes.

An exploratory study of body composition as a predictor of dose-limiting toxicity in metastatic pancreatic cancer treated with gemcitabine plus nab-paclitaxel

BACKGROUND

Body composition is increasingly being studied as a method of predicting chemotherapy toxicity. Our study aimed to evaluate associations of body composition with treatment toxicity in a group of pancreatic cancer patients treated with gemcitabine plus nab-paclitaxel.

METHODS

A retrospective review was performed for all patients who received first-line gemcitabine plus nab-paclitaxel for metastatic pancreatic cancer at a northern Alberta cancer institute (Canada) from 2014 to 2017. Total lean body mass (LBM) was derived from measurements of muscle surface area at L3 on baseline computed tomography (CT) scans. Optimal stratification, or minimal p-value analysis, was used to assess for a threshold of nab-paclitaxel dose per LBM (mg/kg) associated with a higher risk of dose-limiting toxicity (DLT).

RESULTS

152 patients were included in the study, of whom 62 (40.8%) experienced DLT. nab-Paclitaxel dose/LBM ranged from 0.98 to 8.76 mg/kg. A threshold for nab-paclitaxel dose/LBM that optimally predicted risk of DLT was identified at 5.83 mg/kg. Above this cut-off, 18/31 (58.1%) patients experienced DLT, compared to 44/121 (36.4%) patients below (p = 0.028). Patients above this cut-off had a higher incidence of peripheral neuropathy compared to those below, though this was not statistically significant based on an adjusted p-value threshold (48.4 vs. 29.8% respectively, p = 0.050). Body mass index, body surface area, and absolute initial doses of nab-paclitaxel or gemcitabine did not significantly impact likelihood of DLT.

CONCLUSIONS

nab-Paclitaxel dose normalized to LBM, based on CT-derived measures of skeletal muscle, has potential to predict risk of chemotherapy toxicity. Chemotherapy dosing based on body composition, rather than conventional anthropometric measures, may be effective in reducing treatment toxicity.

Phase III randomized trial of cetuximab (CET) plus either brivanib alaninate (BRIV) or placebo in patients (pts) with metastatic (MET) chemotherapy refractory K-RAS wild-type (WT) colorectal carcinoma (CRC): The NCIC Clinical Trials Group and AGITG CO.20 trial

386

Background: The anti-EGFR monoclonal antibody CET has improved survival in pts with MET, chemotherapy refractory, K-RAS wild type (WT) CRC. The addition of BRIV, a tyrosine kinase inhibitor targeting vascular endothelial and fibroblast growth factor receptors (VEGFR/FGFR), to CET has shown encouraging activity in an early phase clinical trial.

Methods: Pts with MET CRC previously treated with combination chemotherapy were randomized 1:1 to receive CET 400 mg/m2 IV loading dose followed by weekly maintenance of 250 mg/m2 plus either BRIV 800 mg PO daily (Arm A) or placebo (Arm B). Pts may have had 1 prior anti-VEGF, but no prior anti-EGFR therapy. The trial was amended shortly after opening to enrol K-RAS WT pts. Primary endpoint was overall survival (OS).

Results: From 02/2008 to 02/2011, 750 pts were randomized (376 in Arm A and 374 in Arm B). Demographics: median age=64 (range 27-88); male=64%; ECOG 0:1:2 (%)=32:58:10; >3 prior chemotherapy regimens=92%; prior anti-VEGF therapy=41%; K-RAS WT=97%. 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=0.12. 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<0.0001. Both partial responses (13.6% vs 7.2%, p=0.004) and stable disease (50% vs 44%) were higher in Arm A. Incidence of any ≥grade 3 adverse event (AE) was 78% in Arm A and 53% in Arm B. Most frequent ≥grade 3 AEs were fatigue (25%), hypertension (11%) and rash (10%) in Arm A, vs fatigue (11%), rash (5%) and dyspnea (5%) in Arm B. Time to deterioration of physical function was shorter and global quality of life scores were lower in Arm A vs Arm B. Pts received ≥90% dose intensity of CET=57% in Arm A vs 83% in Arm B; of BRIV/placebo=48% in Arm A vs 87% in Arm B.

Conclusions: Despite positive effects on PFS and objective response, the combination of CET+BRIV did not significantly improve OS in pts with MET, chemotherapy refractory, K-RAS WT CRC. AEs were consistent with those reported for each drug given as monotherapy.

Drug exposure: still an excellent biomarker

Relationships between plasma drug concentrations and clinical outcome have been defined for various chemotherapeutic agents, showing that drug exposure may be a marker of toxicity, mainly hematological and gastrointestinal toxicity, as well as efficacy, expressed as tumor response and survival. Biomarkers provide information for guidance in dosing and the minimization of interindividual variation in response. Drug exposure is commonly measured with parameters such as area under the plasma concentration-time curve, steady-state plasma or serum concentrations, peak concentrations and duration above a threshold concentration. In this review, we focus on drugs where pharmacokinetic/pharmacodynamic relationships as well as systemic exposure have been associated to toxicity and/or efficacy in solid and hematological tumors, these include: carboplatin, methotrexate, busulphan, 5-fluorouracil, etoposide, anthracyclines, irinotecan, vinorelbine and docetaxel.

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.

Phase I study of an oral formulation of ZD9331 administered daily for 28 days

PURPOSE

To define the maximum-tolerated dose and dose-limiting toxicities (DLTs) of an oral formulation of ZD9331, a novel thymidylate synthase inhibitor that is not a substrate for folylpolyglutamate synthase.

PATIENTS AND METHODS

Patients had Cancer and Leukemia Group B performance status < or = 2 and refractory solid tumors. Initially, patients received ZD9331 daily for 2 weeks, with the duration of treatment escalated to a maximum of 4 weeks, followed by a 2-week rest period. Once the maximum-tolerated duration of treatment was determined, the dose of ZD9331 was increased until DLT occurred.

RESULTS

Fifty-five patients were enrolled at eight dose levels. The DLTs were thrombocytopenia and neutropenia. At 3 mg/d, two of 19 patients developed DLT; one patient had grade 3 thrombocytopenia and grade 4 neutropenia, and the other patient had grade 3 thrombocytopenia only. Anemia was common, with a median hemoglobin nadir of 75% of baseline, before recovery or transfusion. The apparent oral clearance of ZD9931 was 11.6 +/- 6.3 mL/min. Dose-limiting myelosuppression was associated with both an increased 24-hour ZD9931 concentration and blood urea nitrogen.

CONCLUSION

The recommended phase II dose on this schedule is 3 mg/d for 4 weeks, followed by a 2-week rest period. ZD9331 seems to have a manageable toxicity profile, although it should be used with caution in patients with renal impairment.

Myosteatosis is prognostic in metastatic melanoma treated with nivolumab

BACKGROUND

While immunotherapy agents have improved outcomes in metastatic melanoma (MM), predictive biomarkers in these patients are lacking. Parameters identified from body composition analysis, such as low SMD (also termed myosteatosis), may prognosticate MM patients on immunotherapy.

METHODS

In this retrospective study, 44 MM patients received nivolumab, either as monotherapy or in combination with ipilimumab. Pre-treatment computed tomography (CT) scans were analyzed to determine skeletal muscle density (SMD) in Hounsfield units (HU) and muscle surface area (MSA) in cm² at L3. MSA was used to determine nivolumab dosing in mg/cm².

RESULTS

Low SMD was associated with worse overall survival (OS) by log rank test (median 12.03 vs. 34.96 months, p = 0.001) and in multivariate analysis when accounting for age, sex, performance status, and number of prior lines of therapy (HR 4.40, 95% CI 1.44-13.42, p = 0.009). Lower nivolumab dosing by MSA was significantly associated with improved OS (median 42.9 vs. 12.3 months, p < 0.001). This association remained significant in multivariate analysis with age, sex, performance status, and number of prior lines of therapy (HR 0.05, 95% CI 0.01-0.30, p = 0.001). Neither SMD nor higher nivolumab dose per MSA were associated with increased incidence of treatment toxicity.

CONCLUSIONS

Low SMD is prognostic in MM treated with nivolumab immunotherapy. Presence of myosteatosis or higher nivolumab dose based on body composition did not predict treatment toxicity.

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.

A phase I study of H3B-6527 in hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC) patients (pts)

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Background: FGF19 overexpression is hypothesized to hyperactivate FGFR4 and its downstream signaling pathway leading to enhanced tumor growth in HCC/ICC. Targeting FGFR4 may have therapeutic benefit in HCC/ICC with altered FGF19 signaling. A phase 1 study (NCT02834780) was initiated to assess H3B-6527, an investigational highly selective covalent FGFR4 inhibitor. Methods: Adult pts with advanced HCC or ICC, ECOG PS 0-1, well compensated liver function, and who progressed after at least one prior therapy, were administered H3B-6527 orally QD (once daily) on a 21-day cycle following a 3+3 design. Patients in the dose escalation phase were treated regardless of FGF19 status. Adverse events (AEs), pharmacokinetics (PK), and pharmacodynamics (PD) were assessed. Response was determined by RECIST 1.1 or modified RECIST every 6 weeks. Results: As of 06-Jan-2019, 37 pts have been treated with H3B-6527 at doses of 300 to 1400 mg QD (23 pts in escalation; 14 in expansion). In dose escalation, a total of 17 patients with HCC, Child-Pugh A received prior systemic therapy including 100% with prior TKI and 35% with prior IO. 12% had hepatitis B virus and 47% had hepatitis C virus. H3B-6527 plasma levels increased with dose from 300 to 1000 mg QD and plateaued. H3B-6527 was rapidly absorbed with a tmax of ~2-3 h and showed a terminal half-life of ~4-5 h, following administration of 1000 mg (fasted). No dose-limiting toxicities or ≥ Grade 3 treatment-related AEs (TRAE) have been observed in escalation. Most common TRAEs (≥ 10%) were diarrhea, nausea, and vomiting. Based on safety, PK, and PD, 1000 mg QD was the recommended phase 2 dose. Durable stable disease and partial responses (PR) have been observed on the once daily fasted schedule; 2 of 17 pts with HCC achieved PRs and an additional 7 with stable disease were on treatment for ≥ 5 months. Conclusions: H3B-6527 is well tolerated and demonstrates early signs of clinical activity. Dose expansion on QD schedule and exploration of BID (twice daily) schedule is ongoing. Clinical trial information: NCT02834780.

Emergence of power laws in the pharmacokinetics of paclitaxel due to competing saturable processes

Purpose: This study presents the results of power law analysis applied to the pharmacokinetics of paclitaxel. Emphasis is placed on the role that the power exponent can play in the investigation and quantification of nonlinear pharmacokinetics and the elucidation of the underlying physiological processes. Methods: Forty-one sets of concentration-time data were inferred from 20 published clinical trial studies, and 8 sets of area under the curve (AUC) and maximum concentration (Cmax) values as a function of dose were collected. Both types of data were tested for a power law relationship using least squares regression analysis. Results: Thirty-nine of the concentration-time curves were found to exhibit power law tails, and two dominant fractal exponents emerged. Short infusion times led to tails with a single power exponent of -1.57 ± 0.14, while long infusion times resulted in steeper tails characterized by roughly twice the exponent. The curves following intermediate infusion times were characterized by two consecutive power laws; an initial short slope with the larger alpha value was followed by a crossover to a long-time tail characterized by the smaller exponent. The AUC and Cmax parameters exhibited a power law dependence on the dose, with fractional power exponents that agreed with each other and with the exponent characterizing the shallow decline. Computer simulations revealed that a two- or three-compartment model with both saturable distribution and saturable elimination can produce the observed behaviour. Furthermore, there is preliminary evidence that the nonlinear dose-dependence is correlated with the power law tails. Conclusion: Assessment of data from published clinical trials suggests that power laws accurately describe the concentration-time curves and non-linear dose-dependence of paclitaxel, and the power exponents provide insight into the underlying drug mechanisms. The interplay between two saturable processes can produce a wide range of behaviour, including concentration-time curves with exponential, power law, and dual power law tails.

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.

A phase Ib study of oral Chk1 inhibitor LY2880070 in combination with gemcitabine in patients with advanced or metastatic cancer

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Background: LY2880070 (LY) is an oral, selective competitive inhibitor of checkpoint kinase 1 (Chk1). Chk1 inhibitors are known to increase the anti-tumor efficacy of agents such as gemcitabine (GEM), which induce replication stress. Synergy between these two agents has been applied to the clinical setting. Methods: This two-part, open-label multi-center study explores the safety, pharmacokinetics (PK), and anti-tumor activity of LY in patients with advanced or metastatic cancers. The primary objective of this study was to determine the maximum tolerated dose (MTD) for multiple escalating oral doses of LY in combination with GEM. Secondary objectives were to: 1) Characterize the dose-limiting toxicities (DLTs) and overall safety profile for LY; 2) Evaluate the PK of LY; and 3) Evaluate the anti-tumor activity of LY. Patients received LY in a variety of different dose regimens, in combination with GEM (50 to 800 mg/m2) on days 1, 8, and 15 (optional) of a 21-day cycle. Results: The combination of LY with GEM required lower doses of both LY (vs 200 mg BID monotherapy RP2D dose) and GEM (vs approved doses). The dose levels explored ranged from LY:GEM of 10 mg QD:800 mg/m2 to 50 mg BID:100 mg/m2. BID dosing of LY was implemented in order to maximize the total daily dose and avoid the adverse events that appeared to correlate with Cmax. Treatment-emergent adverse events in > 40% of patients included vomiting, nausea, and fatigue. DLTs included reduced platelet count (Gr2), fatigue (Gr3), diarrhea (Gr3), and thrombocytopenia (x2, Gr2). The t1/2 of LY was ~ 5 h, and was not significantly affected by combination with GEM. Two patients had a best overall response of SD for a duration of ≥ 6 cycles, and a confirmed PR was observed in an ovarian cancer patient who had failed multiple regimens. Conclusions: LY was tolerated in combination with lower dose GEM. The toxicity profile can be modulated by changing the dosing frequency from QD to BID while administering the same daily dose. LY may be good candidate for combination therapy with DNA damaging agents. Clinical trial information: NCT02632448 .