Mario Del Tacca

14644 Background: A number of pharmacogenomic studies have been recently carried out to find out a possible relationship between gene expression and treatment outcome in NSCLC; however, to our knowledge, no data are available on the possible influence of tumor histology and tumor stage on gene expression profile. The aim of this study was the characterization of the expression pattern of genes involved in gemcitabine and cisplatin activity in primary or metastatic adenocarcinoma or squamous carcinoma NSCLC specimens. Methods: Excision repair cross-complementing 1 (ERCC1), human equilibrative nucleoside transporter-1 (hENT1), deoxycytidine kinase (dCK), 5’-nucleotidase (5’-NT), cytidine deaminase (CDA), and ribonucleotide reductase subunits M1 and M2 (RRM1 and RRM2) were analyzed by quantitative RT-PCR in 89 laser microdissected lung tissues (52 primary tumors, 23 metastatic lymph nodes and 14 normal lung tissues), from 69 patients. β-actin was used as housekeeping gene. Results: The quantitative expression analysis in patients’ samples demonstrated that these target genes were detectable in most surgical specimens. hENT1, CDA and dCK expression was significantly lower in normal than in tumor tissues (p<0.05). A difference in mean CDA expression was also found between tumor (1.015±0.015) and node metastasis (0.965±0.019). Furthermore, a significant (p<0.05) variability of mean gene expression was observed between adenocarcinoma and squamous cell carcinoma with respect to 5’-NT, RRM1 and RRM2. In particular, the mean gene expression values of both RRM1 and RRM2 were significantly higher in squamous cell carcinomas with respect to adenocarcinomas, while 5’-NT expression values were significantly higher in adenocarcinomas. Conclusions: We have identified the differences in expression of gemcitabine and cisplatin-related genes due to tumor stage and histology. The knowledge of these variations in gene profiles should be be taken into account for pharmacogenomic data interpretation and must be considered in predicting gemcitabine/cisplatin efficacy and in personalizing treatment for lung cancer patients. No significant financial relationships to disclose.

14558 Background: Biliary tract carcinoma is an uncommon malignancy. The activity of systemic chemotherapy is very low and there is no current therapy considered a gold standard. The poor prognosis of cholangiocarcinoma is a result of its biological aggressiveness and therapy resistant nature. Individual variation in DNA repair conferred by single nucleotide polymorphisms (SNPs) affects the clinical response to therapy and overall survival in several neoplasms. In this investigational pharmacogenetic study we retrospectively evaluated the correlations between the following polymorphisms (XPD Asp312Asn and Lys751Gln, ERCC1 C118T, XRCC1 Arg399Gln, and ABCB1 C3435T) and: drug response, progression free and overall survival. Methods: Between June 2006 and August 2007 33 patients (pts) entered this study: seven pts received epirubicin and cisplatin intravenous and 26 pts received epirubicin and cisplatin intra-arterially; all pts received orally capecitabine. Genomic DNA was extracted from blood samples (5 ml) before drug administration. The ERCC1 C118T, XPD Asp312Asn, XPD Lys751Gln, XRCC1 Arg399Gln, and ABCB1 C3435T polymorphisms were studied with Taqman® probes-based assays. Results: PR was observed in 6 out of the 33 evaluable pts (18.2%). SD was observed in 17 pts (51.5%) and PD occurred in 10 pts. (30.3%). After a median follow-up of 7.1 months (range 1–44.7), the median PFS was 4.8 months (range 0.7–21.7) and the median OS was 18.9 months. No significant correlations were observed between response, PFS and OS in patients grouped according to all the studied polymorphisms. However, the Log-rank test suggested an association of the XRCC1Arg/Arg variant with reduced OS which did not reach statistical significance. Furthermore, the analysis of survival starting from the date of diagnosis resulted in a significant association of the homozygous variant XRCC1 Arg/Arg with a shorter survival (11.0 vs 45.6 months, p=0.01). Conclusions: To our knowledge this study is the first pharmacogenetic one in patients affected by biliary tract carcinomas. The results observed in this homogeneous population suggested that the XRCC1 genotype would be useful as prognostic marker in these pts. No significant financial relationships to disclose.

2052 Background: The extensive use of 5-fluorouracil (5-FU) has attracted a great attention on dihydropyrimidine dehydrogenase (DPD), the enzyme responsible for detoxification of 5-FU to 5-fluoro-5,6-dihydrouracil (5-FDHU). The incidence of DPD deficiency is estimated to be around 3% and thus the related 5-FU life-threatening toxicity has significant clinical implications. Methods: In order to (1) investigate the clinical pharmacokinetics (PK) of 5-FU/5-FDHU in cancer patients administered with a 5-FU single low dose, (2) predict the systemic impairment of 5-FU catabolism and (3) prevent severe drug-related toxicity, 112 patients received 5-FU 250 mg/m² as i.v. bolus before starting the planned 5-FU treatment (i.v. bolus of 370 mg/m²/day 5-FU for 5 days, or continuos infusion of 3800 mg/m² 5-FU for 48 h). HPLC analysis was performed on plasma (from 0 to 1.5 h after 5-FU) and peripheral blood mononuclear cell samples to calculate 5-FU/5-FDHU PK parameters and DPD activity, respectively. Adverse events were graded according to WHO scale. Results: The single 5-FU dose did not cause side effects in all tested patients. The 5-FU/5-FDHU PK parameters (mean±SD) are shown in Table 1. A significant correlation between 5-FU AUC and 5-FDHU AUC was found, whereas no correlations between DPD activity and 5-FU/5-FDHU PK were identified. Three patients had marked alterations of 5-FU/5-FDHU PK (e.g. 5-FU t_1/2β>5 h; CL_TB2; 5-FDHU T_max≥45 min) and were excluded from 5-FU treatments. After the first cycle of 5-FU-based therapy, only 4 of the 100 evaluated patients experienced a grade 3 toxicity. Conclusions: PK analysis of plasma 5-FU/5-FDHU after a test dose provides reliable information on the risk of developing toxicities due to impaired 5-FU catabolism and encourages its application to patients candidates to receive 5-FU chemotherapy (e.g. adjuvant treatment of colorectal cancer). No significant financial relationships to disclose.

Azithromycin concentrations in the tonsils of 56 pediatric patients, treated with 10 or 20 mg of the drug per kg of body weight for 3 days, were compared. Azithromycin levels in plasma and tonsil samples were determined up to 8.5 days after the last dose. The 20-mg/kg regimen resulted in an improved tonsillar distribution of azithromycin, suggesting the achievement of enhanced therapeutic concentrations at infective sites of the upper respiratory tract.

Background: The anticancer drug irinotecan induces cholinergic side effects that are currently ascribed to the blockade of acetylcholinesterase. This study investigated (1) the pattern of acetylcholinesterase activity in patients receiving treatment with irinotecan and (2) the relationship between acetylcholinesterase activity and plasma concentrations of irinotecan, 7‐ethyl‐10‐hydroxycamptothecin (SN‐38), and SN‐38 glucuronide (SN‐38G).Methods: Twenty‐five patients with advanced colorectal cancer were treated with 250 mg/m² irinotecan administered by intravenous infusion for 60 minutes. Blood samples were collected before drug infusion and at 15 minutes and 45 minutes after the start of drug infusion. Blood acetylcholinesterase activity was determined by a colorimetric enzymatic assay, and irinotecan, SN‐38, and SN‐38G concentrations were determined in plasma by HPLC. The in vitro effects of irinotecan and other drugs on human acetylcholinesterase were also assessed.Results: Compared with basal values, the activity of acetylcholinesterase in blood specimens collected during irinotecan infusion at 15 minutes (−0.76%) and at 45 minutes (−1.50%) showed no changes. No relationships were established between the activity of blood acetylcholinesterase at 15 or 45 minutes and plasma concentrations of irinotecan, SN‐38, or SN‐38G measured at the same time points. In vitro, the activity of acetylcholinesterase was inhibited by 100‐μmol/L irinotecan (−24.8%) and markedly reduced by 1‐μmol/L physostigmine (−86.7%), whereas neither SN‐38 nor camptothecin had an effect.Conclusions: Although the use of erythrocyte acetylcholinesterase as a surrogate marker of acetylcholinesterase activity in the nervous system has not been firmly established, our findings do not support the hypothesis that the toxic cholinergic syndrome associated with irinotecan treatment depends on acetylcholinesterase blockade.Clinical Pharmacology & Therapeutics (2002) 71, 263–271; doi: 10.1067/mcp.2002.121909