Role of thyroid stimulating hormone in the maintenance and functioning of the human corpus luteum.

PURPOSE: To evaluate the impact of high thyroid stimulating hormone (TSH) levels on human granulosa-luteal (hGL) cells. METHODS: hGL cells were isolated from follicular aspirates derived from patients undergoing IVF treatment without any thyroid disorder (serum TSH 0.5-2 mU/L). Cells were cultured at 37 °C in DMEM, supplemented with 5% FBS. The cells were treated with 1 nM LH and increasing concentrations of TSH. At the end of culture, conditioned medium and cells were collected to analyze progesterone production, cell viability, and mRNA levels of genes involved in the steroidogenesis process. Human ovarian tissues were analyzed for TSH receptor (TSHR) expression by IHC. RESULTS: The expression of TSHR was detected in human corpus luteum by IHC and in hGL by RT-PCR. In hGL cells, TSH treatment did not modulate progesterone production nor the expression of steroidogenic genes, such as p450scc and HSD3b 1/2. However, TSH induced a dose-dependent increase in cell death. Finally, TSH did not affect LH-induced p450scc and HSD3b1/2 expression while LH partially reverted TSH negative effect on cell death in hGL. CONCLUSIONS: Elevated TSH levels in hypothyroid women may be associated with impaired CL functioning and maintenance. These findings open a new line of research for the importance of the treatment of women with thyroid dysfunction that could contribute to the onset of infertility.

ABC transporter polymorphisms are associated with irinotecan pharmacokinetics and neutropenia.

Neutropenia is a common dose-limiting toxicity associated with irinotecan treatment. Although UGT1A1 variants have been associated with neutropenia, a fraction of neutropenia risk remains unaccounted for. To identify additional genetic markers contributing to variability in irinotecan pharmacokinetics and neutropenia, a regression analysis was performed in 78 irinotecan-treated patients to analyze comprehensively three hepatic efflux transporter genes (ABCB1, ABCC1 and ABCG2). rs6498588 (ABCC1) and rs12720066 (ABCB1) were associated with increased SN-38 exposure, and rs17501331 (ABCC1) and rs12720066 were associated with lower absolute neutrophil count nadir. rs6498588 and a variant in high linkage disequilibrium are located in transcriptionally active regions or are predicted to alter transcription factor binding sites. While enhancer activity was not evident in vitro for genomic regions containing these single-nucleotide polymorphisms, rs6498588 was significantly associated with ABCC1 expression in human liver. These results suggest that genetic variation in ABCC1 and ABCB1 may contribute to irinotecan-induced neutropenia by altering expression of transporters involved in irinotecan metabolite disposition.

Predicted vitamin D status and colon cancer recurrence and mortality in CALGB 89803 (Alliance).

BACKGROUND: Observational studies suggest that higher levels of 25-hydroxyvitamin D3 (25(OH)D) are associated with a reduced risk of colorectal cancer and improved survival of colorectal cancer patients. However, the influence of vitamin D status on cancer recurrence and survival of patients with stage III colon cancer is unknown. PATIENTS AND METHODS: We prospectively examined the influence of post-diagnosis predicted plasma 25(OH)D on outcome among 1016 patients with stage III colon cancer who were enrolled in a National Cancer Institute-sponsored adjuvant therapy trial (CALGB 89803). Predicted 25(OH)D scores were computed using validated regression models. We examined the influence of predicted 25(OH)D scores on cancer recurrence and mortality (disease-free survival; DFS) using Cox proportional hazards. RESULTS: Patients in the highest quintile of predicted 25(OH)D score had an adjusted hazard ratio (HR) for colon cancer recurrence or mortality (DFS) of 0.62 (95% confidence interval [CI], 0.44-0.86), compared with those in the lowest quintile (Ptrend = 0.005). Higher predicted 25(OH)D score was also associated with a significant improvement in recurrence-free survival and overall survival (Ptrend = 0.01 and 0.0004, respectively). The benefit associated with higher predicted 25(OH)D score appeared consistent across predictors of cancer outcome and strata of molecular tumor characteristics, including microsatellite instability and KRAS, BRAF, PIK3CA, and TP53 mutation status. CONCLUSION: Higher predicted 25(OH)D levels after a diagnosis of stage III colon cancer may be associated with decreased recurrence and improved survival. Clinical trials assessing the benefit of vitamin D supplementation in the adjuvant setting are warranted. CLINICALTRIALS.GOV IDENTIFIER: NCT00003835.

Clinical validity of new genetic biomarkers of irinotecan neutropenia: an independent replication study.

The overall goal of this study was to provide evidence for the clinical validity of nine genetic variants in five genes previously associated with irinotecan neutropenia and pharmacokinetics. Variants associated with absolute neutrophil count (ANC) nadir and/or irinotecan pharmacokinetics in a discovery cohort of cancer patients were genotyped in an independent replication cohort of 108 cancer patients. Patients received single-agent irinotecan every 3 weeks. For ANC nadir, we replicated UGT1A1*28, UGT1A1*93 and SLCO1B1*1b in univariate analyses. For irinotecan area under the concentration-time curve (AUC0-24), we replicated ABCC2 -24C>T; however, ABCC2 -24C>T only predicted a small fraction of the variance. For SN-38 AUC0-24 and the glucuronidation ratio, we replicated UGT1A1*28 and UGT1A1*93. In addition to UGT1A1*28, this study independently validated UGT1A1*93 and SLCO1B1*1b as new predictors of irinotecan neutropenia. Further demonstration of their clinical utility will optimize irinotecan therapy in cancer patients.

A novel UGT1 marker associated with better tolerance against irinotecan-induced severe neutropenia in metastatic colorectal cancer patients.

The risk of severe irinotecan-induced neutropenia has been shown to be related to the UGT1 variant UGT1A1*28, which increases exposure to the potent metabolite SN-38. Our goal was to identify a novel UGT1 marker(s) using 28 haplotype-tagged single nucleotide polymorphisms genotyped by mass spectrometry. By characterizing the UGT1 sequence from a cohort of 167 Canadian metastatic colorectal cancer (mCRC) patients and a validation cohort of 250 Italian mCRC patients, we found rs11563250G, located in the intergenic region downstream of UGT1, to be significantly associated with reduced risk of severe neutropenia (odds ratio (OR)=0.21; P=0.043 and OR=0.27; P=0.036, respectively, and OR=0.31 when combined; P=0.001), which remained significant upon correction for multiple testing in the combined cohort (P=0.041). For the two-marker haplotype rs11563250G and UGT1A1*1 (rs8175347 TA6), the OR was of 0.17 (P=0.0004). Genetic testing of this marker may identify patients who might benefit from increased irinotecan dosing.

A prospective validation pharmacogenomic study in the adjuvant setting of colorectal cancer patients treated with the 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX4) regimen.

The discovery of pharmacogenomic markers in colorectal cancer (CRC) could be setting-specific. FOLFOX4 is employed in the adjuvant and metastatic setting in CRC. This prospective study is aimed to validate in the adjuvant setting the pharmacogenomic markers of toxicity reported in the metastatic setting (that is, GSTP1-rs947894, and -rs1138272; GSTM1-null genotype; AGXT-rs4426527, -rs34116584 and del-74 bp), and to discover additional markers. CRC patients (n=144) treated with adjuvant FOLFOX4 were genotyped for 57 polymorphisms in 29 genes. Grade ≥ 2 neurotoxicity was associated (false discovery rate-adjusted q-value <0.1) with single-nucleotide polymorphisms in ABCC1 (rs2074087: odds ratio=0.43(0.22-0.86)), and ABCC2 (rs3740066: 2.99(1.16-7.70); rs1885301: 3.06(1.35-6.92); rs4148396: 4.69(1.60-13.74); rs717620: 14.39(1.63-127.02)). hMSH6-rs3136228 was associated with grade 3-4 neutropenia (3.23(1.38-7.57), q-value=0.0937). XRCC3-rs1799794 was associated with grade 3-4 non-hematological toxicity (8.90(2.48-31.97), q-value=0.0150). The markers previously identified in metastatic CRC were not validated. We have identified new markers of toxicity in genes of transport and DNA repair. If validated in other studies, they could help to identify patients at risk of toxicity.

Nucleotide excision repair gene variants and association with survival in osteosarcoma patients treated with neoadjuvant chemotherapy.

The aim of this study was to investigate the role of common polymorphisms in the nucleotide excision repair pathway genes in the tumorigenesis of osteosarcoma and in the response to DNA damaging therapies, such as cisplatin-based neoadjuvant therapy. Excision repair cross-complementing (ERCC) group 2 (XPD; rs13181 and rs1799793), group 5 (XPG; rs17655) and group 1 (XPA; rs3212986 and rs11615) polymorphisms were analyzed in a group of 130 homogenously treated patients with high-grade osteosarcoma, for association with event-free survival (EFS), using the Kaplan-Meier plots and log-rank test. A positive association was observed between both XPD single-nucleotide polymorphisms and an increased EFS (hazards ratio (HR) = 0.34, 95% confidence interval (CI) 0.12-0.98 and HR = 0.19, 95% CI 0.05-0.77, respectively). We had also performed a case-control study for relative risk to develop osteosarcoma. Patients carrying at least one variant allele of XPD rs1799793 had a reduced risk of developing osteosarcoma, compared with wild-type patients (odds ratio = 0.55, 95% CI 0.36-0.84). This study suggests that XPD rs1799793 could be a marker of osteosarcoma associated with features conferring either a better prognosis or a better outcome after platinum therapy, or both.

Stratification of patients admitted for SARS-CoV2 infection: prognostic scores in the first and second wave of the pandemic.

To test the prognostic performance of different scores, both specifically designed for patients with COVID-19 and generic, in predicting in-hospital mortality and the need for mechanical ventilation (MV). We retrospectively collected clinical data of patients admitted to the Emergency Department of the University Hospital AOU Careggi, Florence, Italy, between February 2020 and January 2021, with a confirmed infection by SARS-CoV2. We calculated the following scores: Sequential Organ Failure Assessment (SOFA) score, CALL score, 4C Mortality score, QUICK score, CURB-65 and MuLBSTA score. The end-points were in-hospital mortality and the need for MV. We included 1208 patients, mean age 60 ± 17 years, 57% male sex. Compared to survivors, non-survivors showed significantly higher values of all the prognostic scores (4C: 13 [10-15] vs 8 [4-10]; CALL: 11 [10-12] vs 9 [7-11]; QUICK: 4 [1-6] vs 0 [0-3]; SOFA: 5 [4-6] vs 4 [4-5]; CURB: 2 [1-3] vs 1 [0-1]; MuLBSTA: 11 [9-13] vs 9 [7-11], all p < 0.001). Discriminative ability evaluated by the Receiver Operating Curve analysis showed the following values of the Area under the Curve: 0.83 for 4C, 0.74 for CALL, 0.70 for QUICK, 0.68 for SOFA, 0.76 for CURB and 0.64 for MuLBSTA. The mortality rate significantly increased in increasing quartiles of 4C and CALL score (respectively, 2, 8, 24 and 54% for the 4C score and 1, 17, 33 and 68% for the CALL score, both p < 0.001). 4C and CALL score allowed an early and good prognostic stratification of patients admitted for pneumonia induced by SARS-CoV2.

Regulating landfills using measured methane emissions: An English perspective.

Methane emissions from landfills are an important source of greenhouse gases in the UK and worldwide. This paper considers how measurements of methane emissions could be used to regulate landfills in England in order to reduce the contribution of landfilling to climate change. The paper presents the results of a number of UK studies undertaken to quantify methane emissions from landfills. The methods used have included the DIAL (Differential Absorption Lidar) technique and a tracer gas dispersion method. A method based on aerial measurements has been developed. Methane emission rates were measured at 15 biodegradable waste landfills. All of the landfills where measurements took place had an active landfill gas extraction system. A methane collection index (MCI) is calculated for each landfill using the ratio of the methane collection rate to the sum of the collection and emission rates. The values of the index in the campaigns reported here ranged from 0.28 to 0.90. The modern operational landfills surveyed achieved MCI values with a much narrower range of between 0.64 and 0.90 with an average of 0.76. This has demonstrated that it is possible for these landfills to collect a high proportion of the landfill gas. A proposed approach is presented for regulating landfills using the measured MCI. This would involve an annual measurement campaign to quantify the methane emissions and the use of the data provided by these surveys to develop an achievable but challenging MCI limit. A limit value of 0.75 for the MCI is used to illustrate the approach. An MCI that falls below the limit would trigger actions to reduce the methane emissions from the landfill.

Hepatocyte nuclear factor-1 alpha is associated with UGT1A1, UGT1A9 and UGT2B7 mRNA expression in human liver.

Experimental evidence suggests HNF1alpha regulates UGT expression. This study investigates (1) whether the variability in HNF1alpha expression is associated with the variability in UGT1A1, UGT1A9 and UGT2B7 expression in human livers and (2) the functionality of 12 HNF1alpha variants using mRNA expression as phenotype. Controlling for known UGT variation in cis-acting elements known to affect UGT expression, we demonstrate that a combination of HNF1alpha mRNA levels and UGT genotype predicts variance in UGT expression to a higher extent than UGT genotype alone. None of the HNF1alpha polymorphisms studied, however, seem to have an effect on HNF1alpha, UGT1A1, UGT1A9 and UGT2B7 expression, ruling out their functional role. Our data provide evidence for HNF1alpha being a determinant of UGT1A1, UGT1A9 and UGT2B7 mRNA expression. However, the amount of UGT intergenotype variability explained by HNF1alpha expression appears to be modest, and further studies should investigate the role of multiple transcription factors.

"No pain, No gain" still true with immunotherapy: When the finger shows the moon, look at the moon!

There is a rising evidence that the proverbial statement "No pain, No gain" first coined at the light of pioneering clinical experiences with canonical chemotherapy still holds true in the era of modern treatments of cancer. This close relationship between the occurrence of specific drug-related toxicity and treatment outcome has been confirmed since then with a large variety of treatments, ranging from cytotoxics, hormonotherapy, targeted therapy and much interestingly even with the latest immune checkpoint inhibitors. In the current context of precision medicine, and along with the constant quest for identifying predictive biomarkers, close monitoring of treatment-related toxicities could therefore be convenient to help predicting therapeutic response, but presents several caveats. The purpose of this review is to briefly describe these relationships across the different treatments, to comment on possible underlying mechanisms and to comment on possible strategies aiming at exploiting this relationship while keeping the maximal safety ensured in patients with cancer. In particular, this review will investigate on how drug exposure along with germinal and somatic genetic issues does impact on the "No Pain, No Gain" aphorism, and why the temptation to use treatment-related toxicities as a cheap and convenient way to predict clinical outcome or to adapt dosing should be resisted. We do advocate instead for developing comprehensive genomic support along with extensive biomathematical modeling to better customize dosing and shift towards a new "No Pain, Maximal Gain" paradigm.

Chest Abdominal-Focused Assessment Sonography for Trauma during the primary survey in the Emergency Department: the CA-FAST protocol.

PURPOSE: To evaluate the feasibility of a new protocol, Chest Abdominal-Focused Assessment Sonography for Trauma (CA-FAST), during the primary survey and to estimate its diagnostic accuracy when compared with thoracoabdominal computed tomography (CT) scan. METHODS: A prospective accuracy study was performed from November 2012 to November 2013 at the Emergency Department. Only adult trauma patients who underwent a CA-FAST examination prior to a thoracoabdominal CT scan were enrolled. In addition to standard patterns detected by Extended-FAST (E-FAST) such as pneumothorax (PTX), hemothorax (HTX), pericardial and intraabdominal effusion, CA-FAST protocol also included the research of lung contusions (LCs). RESULTS: Six hundred and one patients were enrolled. The mean time for protocol execution was 7 ± 3 min. Chest ultrasonography showed the following results (all p < 0.001): LCs sensitivity 59 %, specificity 98 %, positive predictive value (PPV) 92 %, negative predictive value (NPV) 86 %, accuracy 87 %; PTX sensitivity 84 %, specificity 98 %, PPV 93 %, NPV 95 %, accuracy 95 %; HTX sensitivity 82 %, specificity 97 %, PPV 87 %, NPV 95 %, accuracy 94 %. The standard 4-views FAST examination showed a diagnostic accuracy of 91 % with a sensitivity of 75 %, specificity of 96 %, PPV of 81 % and NPV of 94 %. CONCLUSION: According to our results CA-FAST protocol proved to be a rapid bedside method, with good accuracy and high NPV in detection of ultrasonographic patterns suggestive of serious injury in trauma patients; moreover, the additional research of LCs did not cause a delay in the diagnosis. Ultrasonography should be used as initial investigation during the primary survey, sending to further diagnostic studies (CT scan) only those patients not clearly classified.

Prescribing patterns of antiepileptic drugs in Italy: a nationwide population-based study in the years 2000-2005.

To evaluate prevalence of use and prescribing patterns of antiepileptic drugs (AEDs) in Italian general practice. Primary care data were obtained from the Health Search Database, a longitudinal observational database implemented by the Italian College of General Practitioners (GPs). We selected 465 061 subjects registered by the end of 2005 in the lists of 320 GPs, homogeneously distributed throughout Italy. Prevalence of AED use was assessed in the entire sample and by drug type, age group, year and main geographic area (north, centre and south/islands). Overall, 24 383 subjects (5.2%) received at least one AED prescription in the study period. Prevalence of AED use (with 95% confidence interval) increased progressively from 7.1 (6.9-7.3) in 2000 to 11.8 (11.5-12.1) in 2005 for old AEDs and from 1.1 (1.0-1.2) to 12.2 (11.9-12.5) for new AEDs. Carbamazepine, phenobarbital and valproic acid were the most common AEDs until 2003, when gabapentin became first. There were no differences in prescribing patterns in the three main geographic areas. Newer AEDs were mostly used in patients aged 65 years and older. The more widespread use of newer AEDs was for mood disorders or pain. Older AED currently remain first line drugs for epileptic disorders. An increasing use of AEDs has been recently observed over a 6-year period in Italian general practice, mostly explained by newer compounds used for conditions other than epilepsy.

Cost Evaluation of Irinotecan-Related Toxicities Associated With the UGT1A1*28 Patient Genotype.

The adoption of a preemptive UGT1A1*28 genotyping to increase irinotecan safety in clinical practice is still limited. This is the first actual study of costs associated with the management of irinotecan-related toxicities, and their association with UGT1A1*28 genotype. A retrospective analysis of the cost of toxicity management was conducted on 243 metastatic colorectal cancer patients enrolled in a clinical trial and treated with standard of care FOLFIRI (5-fluorouracil combined with irinotecan). The mean predicted cost per patient was higher for *28/*28 (€4,886), vs. *1/*1 (€812), (regression coefficient 1.79, 95% confidence interval (CI) = 1.31-2.28; P < 0.001) and for *1/*28 (€1,119) vs. *1/*1 (regression coefficient 0.32, 95% CI = 0.04-0.60; P = 0.024). This is consistent with a different grade 4 toxicity profile among the three genotypes, and a higher frequency of costly interventions like hospitalization among patients with the *28 allele. A differential toxicity management cost by *28 genotype is herein demonstrated, representing a first step towards the demonstration of the test clinical utility.

Dose-finding study and pharmacokinetics of epirubicin and paclitaxel over 3 hours: a regimen with high activity and low cardiotoxicity in advanced breast cancer.

PURPOSE: To determine the maximum-tolerated dose (MTD) of paclitaxel over 3 hours with a fixed dose of epirubicin, to investigate the plasma pharmacokinetics of this combination, and to evaluate the toxicity and the activity in previously untreated metastatic breast cancer patients. PATIENTS AND METHODS: Fifty patients with metastatic breast cancer, measurable disease, and normal left ventricular ejection fraction (LVEF) were eligible. Epirubicin was administered as an intravenous (I.V.) bolus at the fixed dose of 90 mg/m2 before the infusion of paclitaxel over 3 hours. The initial dose of paclitaxel was 135 mg/m2 and was increased by 20 mg/m2 in subsequent cohorts of six patients until dose-limiting toxicity (DLT). Plasma pharmacokinetics of paclitaxel and epirubicin was performed at cycle 1 in at least two patients per dose level of paclitaxel (175 up to 225 mg/m2). RESULTS: The DLT of this combination was febrile neutropenia in two of eight patients who received paclitaxel at 225 mg/m2. The mean peak plasma concentration of paclitaxel ranged between 5.1 and 6.2 micromol/L at doses of 175 to 225 mg/m2. The concentration of epirubicinol decreased from 47.3 +/- 9.4 to 37.9 +/- 7.5 ng/mL in patients treated with paclitaxel 175 and 225 mg/m2. The most relevant toxicity was grade 4 neutropenia (61% of all courses). The pharmacokinetic data of paclitaxel, in particular the time above the threshold level of 0.05 micromol/L, were not significantly related to myelosuppression. Cardiac toxicity was mild: three patients (6%) developed mild congestive heart failure that was responsive to therapy. Among 49 assessable patients, 41 responses (84%; 95% confidence interval [CI], 70% to 92%) were observed, and nine (18%) of these were complete. CONCLUSION: Our study demonstrates that (1) the MTD is epirubicin 90 mg/m2 and paclitaxel 200 mg/m2; (2) no clear relationship exists between pharmacokinetic data of paclitaxel and myelosuppression, while the increase in the dose of paclitaxel is associated with a reduction in epirubicinol plasma levels; and (3) the association is feasible, with low cardiotoxicity, and has a high activity in metastatic breast cancer.

Increased dose-intensity of gemcitabine in advanced non small cell lung cancer (NSCLC): a multicenter phase II study in elderly patients from the "polmone toscano group" (POLTO).

Gemcitabine is usually administered at a planned dose-intensity (DI) from 750 to 800 mg/m2/week. Preclinical data have suggested a possible dose-response relationship of gemcitabine. A multicenter phase II study was conducted to evaluate the activity in terms of no progression rate (complete responses+partial responses+stable diseases) of gemcitabine administered at an increased DI (1000 mg/m2/week) in elderly advanced non-small-cell lung cancer (NSCLC) patients. Secondary endpoints were to evaluate tolerability, progression free survival and overall survival. Elderly (age>or=70 years) chemo-naive advanced NSCLC patients, ECOG PS 0-2, were treated with intravenous gemcitabine 1500 mg/m2 intravenous (30 min infusion) on days 1 and 8 every 21 days for four courses. One hundred and twenty-two patients with a median age of 75 years (range 70-84) entered the study. The following grade 3 (NCI-CTC) haematological toxicities were reported (percent of patients): neutropenia 2.4%, thrombocytopenia 1.6%, anaemia 2.4%. No grades 3-4 non-haematological toxicities were observed. Among 111 evaluable patients 52 (46.8%) no progressions, 17 (15.3%) partial responses (WHO criteria), 35 (31.5%) stable diseases and 59 (53.2%) progressions were observed. Median time to progression was 3.2 months and median duration of survival was 5.4 months. The overall 1-year survival rate was 27%. Although increased dose-intensity of gemcitabine in elderly NSCLC patients is feasible without severe toxicities, this does not seem to be associated with an increased activity and efficacy in comparison to standard gemcitabine regimens with lower dose-intensities.

Flavopiridol metabolism in cancer patients is associated with the occurrence of diarrhea.

Flavopiridol, a cyclin-dependent kinase inhibitor currently undergoing clinical evaluation, has a dose-limiting toxicity of diarrhea. Preclinical data on flavopiridol metabolism indicate that flavopiridol undergoes hepatic glucuronidation. The purpose of this study is to evaluate whether the occurrence of diarrhea is related to the systemic glucuronidation of flavopiridol. Parent drug and metabolite concentrations in plasma were measured by high-pressure liquid chromatography in 22 metastatic renal cancer patients treated on a Phase II trial of 50 mg/m2/day of flavopiridol administered every 2 weeks as a 72-h continuous infusion. Pharmacokinetics of flavopiridol and its glucuronide were assessed during the first cycle at 23, 47, and 71 h during the infusion. Flavopiridol concentrations at 23, 47, and 71 h were 389 nM (296-567 nM), 412 nM (297-566 nM), and 397 nM (303-597 nM) [median (interquartile range)], respectively. Flavopiridol glucuronide reached a plateau of 358 nM (196-553 nM) at 47 h. Metabolic ratios of flavopiridol glucuronide:flavopiridol at 71 h showed an apparent bimodal distribution with an antimode of 1.2. Thirteen patients experienced diarrhea and had lower metabolic ratios [0.72 (0.53-0.86)] than patients without diarrhea [2.24 (1.76-2.3); P = 0.002]. Eight of 11 extensive glucuronidators (ratio > 1.2) did not develop diarrhea, whereas 10 of 11 poor glucuronidators (ratio < 1.2) developed diarrhea (P = 0.008). The glucuronidation of flavopiridol is apparently polymorphic, suggesting a genetic etiology. The systemic glucuronidation of flavopiridol is inversely associated with the risk of developing diarrhea.

Comparative pharmacokinetic analysis of 5-fluorouracil and its major metabolite 5-fluoro-5,6-dihydrouracil after conventional and reduced test dose in cancer patients.

The aim of this study was to investigate the clinical pharmacokinetics of 5-fluorouracil (5-FU) and its major metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) in 20 colorectal cancer patients given two dose levels of 5-FU, 250 and 370 mg/m2, administered by i.v. bolus. A reverse-phase high-performance liquid chromatographic method was used for the simultaneous assay of 5-FU and 5-FDHU in plasma samples obtained at baseline and at multiple time points from 5 min to 4 h after 5-FU bolus as well as to assess the activity of dihydropyrimidine dehydrogenase (DPD) in peripheral blood mononuclear cells (PBMCs) before 5-FU dosing. Plasma pharmacokinetic parameters of patients given 250 mg/m2 5-FU were significantly different from those receiving 370 mg/m2; main differences were observed in the trapezoidal areas under the plasma levels-versus-time curve from to to the last measurable concentration (area under the curve, 3.77+/-0.21 versus 13.61+/-2.3 h x microg/ml), peak plasma concentration (Cmax, 18.15+/-1.35 versus 48.41+/-7.69 microg/ml), and total body clearance (CL(TB), 54.64+/-3.54 versus 25.43+/-2.3 l/h/m2). Significant differences were also observed in the main pharmacokinetic parameters of 5-FDHU after 250 and 370 mg/m2 5-FU including the area under the curve from to to 4 h (5.39+/-0.32 versus 8.75+/-1.24 h x microg/ml), Cmax (3.60+/-0.16 versus 5.26+/-0.55 microg/ml) and time to Cmax (Tmax, 0.45+/-0.03 versus 0.69+/-0.06 h). The mean DPD activity in PBMCs in this group of patients was 205.7+/-36.4 pmol of 5-FDHU/min/mg of protein and was within the normal range; however, no significant correlations were found between 5-FU or 5-FDHU pharmacokinetic parameters at two dose levels and DPD activity of PBMCs. The results of the present study provide the first detailed comparison of the distribution of 5-FU and its major metabolite 5-FDHU at the therapeutic level as well as at reduced test dose levels to obtain pharmacokinetic data to be used as reference values for the identification of patients at risk of major 5-FU toxicity due to impaired metabolism to 5-FDHU.

Update on pharmacogenetics in cancer chemotherapy.

This review describes how genetic differences among patients may change the therapeutic outcome in cancer chemotherapy. Severe toxicity in genetically predisposed patients is predominantly associated with mutations in drug metabolism enzyme genes, and an update on genetic intolerance to 6-mercaptopurine, 5-fluorouracil, and irinotecan is provided. Moreover, recent findings pointed out that the methylenetetrahydrofolate reductase (MTHFR) C677T mutation might change patient susceptibility to the toxic effects of the cyclophosphamide, methotrexate, 5-fluorouracil (CMF) regimen and raltitrexed. Finally, it is emerging that not only toxicity, but also response to chemotherapy could be influenced by pharmacogenetic determinants, and the clinical relevance of polymorphisms in thymidylate synthase (TS) and glutathione-S-transferase (GST) genes is discussed.