Fumio Nagashima

FCGR2A and FCGR3A Polymorphisms Associated With Clinical Outcome of Epidermal Growth Factor Receptor–Expressing Metastatic Colorectal Cancer Patients Treated With Single-Agent Cetuximab

PURPOSE Cetuximab, a chimeric immunoglobulin G 1 (IgG1) anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb), has shown efficacy in 10% of patients with metastatic colorectal cancer (CRC). Recent studies demonstrate antibody-dependent cell-mediated cytotoxicity (ADCC) is one of the modes of action for rituximab and trastuzumab. Fragment c (Fc) portion of IgG1 mAb has shown to induce ADCC. Fragment c gamma receptors (FcgammaR) play an important role in initiating ADCC. Studies have shown that two IgG FcgammaR polymorphisms (FCGR2A-H131R and FCGR3A-V158F) independently predict response to rituximab in patients with follicular lymphoma. We tested the hypothesis of whether these two polymorphisms are associated with clinical outcome in metastatic CRC patients treated with single-agent cetuximab. PATIENTS AND METHODS Thirty-nine metastatic CRC patients were enrolled onto the ImClone0144 trial. Using an allele-specific polymerase chain reaction (PCR) -based method, gene polymorphisms of FCGA2A-H131R and FCGA3A-V158F were assessed from genomic DNA extracted from peripheral blood samples. RESULTS FCGR2A-H131R and FCGR3A-V158F polymorphisms were independently associated with progression-free survival (PFS; P = .037 and .055, respectively; log-rank test). Combined analysis of these two polymorphisms showed that patients with the favorable genotypes (FCGR2A, any histidine allele, and FCGR3A, any phenylalanine allele) showed a median PFS of 3.7 months (95% CI, 2.4 to 4.4 months), whereas patients with any two unfavorable genotypes (FCGR2A arginine/arginine or valine/valine) had a PFS of 1.1 months (95% CI, 1.0 to 1.4 months; P = .004; log-rank test). CONCLUSION Our preliminary data suggest that these two polymorphisms may be useful molecular markers to predict clinical outcome in metastatic CRC patients treated with cetuximab and that they may indicate a role of ADCC of cetuximab.

Nonrandomized comparison between definitive chemoradiotherapy and radical surgery in patients with T2–3Nany M0 squamous cell carcinoma of the esophagus

PURPOSE To compare the treatment results between radical surgery and definitive chemoradiotherapy for resectable squamous cell carcinoma of the esophagus and to identify useful clinicopathologic and biologic markers to select better treatment. METHODS AND MATERIALS Between August 1992 and April 1999, 98 consecutive patients were selected for this study; 53 were treated with chemoradiotherapy and 45 with surgery. The patients in the chemoradiotherapy group received 5-fluorouracil combined with cisplatin plus 60 Gy of radiation, and those in the surgery group received an esophagectomy with radical node dissection. Biologic markers were investigated immunohistochemically using pretreatment biopsy specimens. RESULTS The baseline clinical TNM stage was more advanced in the chemoradiotherapy group than in the surgery group. With a median follow-up period of 43 months, the 5-year survival rate was 46% in the chemoradiotherapy and 51% in the surgery group, without statistical significance (p = 0.47, log-rank test). Cox regression analysis for prognosis revealed that epidermal growth factor receptor positivity, high microvessel density, and cyclin D1 positivity yielded a low value for relative risk (0.66, 0.54, and 0.62, respectively), which favored chemoradiotherapy over surgery, without statistical significance. CONCLUSION This nonrandomized study showed a trend for the chemoradiotherapy in the treatment of esophageal carcinoma, but the results need to be confirmed by additional study.

Polymorphisms in Cyclooxygenase-2 and Epidermal Growth Factor Receptor Are Associated with Progression-Free Survival Independent of K-ras in Metastatic Colorectal Cancer Patients Treated with Single-Agent Cetuximab

Purpose: Recently, an objective response rate of 12% was reported in a phase II study of cetuximab in patients with epidermal growth factor receptor (EGFR)-expressing metastatic colorectal cancer (mCRC) refractory to fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy (IMC-0144). In this large molecular correlates study, we tested whether K-ras mutation status and polymorphisms in genes involved in the EGFR-signaling pathway were associated with clinical outcome in IMC-0144. Experimental Design: We analyzed all available tissue samples from 130 of 346 mCRC patients enrolled in the IMC-0144 phase II clinical trial of cetuximab. Genomic DNA was extracted from formalin-fixed paraffin-embedded tumor tissues, and K-ras mutation status and the genotypes were analyzed using PCR-RFLP, direct DNA-sequencing, and 5′-end [γ-33P] ATP–labeled PCR-protocols. Results: The PFS of patients with cyclooxygenase-2 (COX-2) −765 G>C [C/C; risk ratio (RR), 0.31; 95% confidence interval (95% CI), 0.12-0.84; P = 0.032], COX-2 +8473 T>C (C/C; RR, 0.67; 95% CI, 0.40-1.13; P = 0.003), EGF +61 A>G (G/G; RR, 0.57; 95% CI, 0.34-0.95; P = 0.042), and EGFR +497 G>A (A/G; RR, 0.82; 95% CI, 0.56-1.20; P = 0.017) genotypes was significantly longer compared with those with other genotypes. In addition, patients whose tumors did not have K-ras mutations showed better RR, PFS, and overall survival than patients with K-ras mutations. In multivariable analysis, COX-2 +8473 T>C (adjusted P = 0.013) and EGFR +497 G>A (adjusted P = 0.010) remained significantly associated with progression-free survival, independent of skin rash toxicity, K-ras mutation status, and Eastern Cooperative Group performance status. Conclusions: Polymorphisms in COX-2 and EGFR may be useful independent molecular markers to predict clinical outcome in patients with mCRC treated with single-agent cetuximab, independent of skin rash toxicity, K-ras mutation, and Eastern Cooperative Oncology Group performance status.

Pharmacogenetic impact of polymorphisms in the coding region of the UGT1A1 gene on SN‐38 glucuronidation in Japanese patients with cancer

Pharmacogenetic testing for UDP‐glucuronosyltransferase (UGT) 1A1*28, a promoter variant of the UGT1A1 gene, is now carried out clinically to estimate the risk of irinotecan‐associated toxicity. We studied the clinical significance of UGT1A1*6 and UGT1A1*27, two variants in exon 1 of the UGT1A1 gene that are found mainly in Asians. The study group comprised 46 Japanese patients who received various regimens of chemotherapy including irinotecan at doses from 50 to 180 mg/m2. Pharmacogenetic relationships were explored between the UGT1A1 genotype and the ratio of the area under the plasma concentration–time curve (AUC) of the active metabolite of irinotecan (SN‐38) to that of SN‐38 glucuronide (SN‐38G), used as a surrogate for UGT1A1 activity (AUCSN‐38/AUCSN‐38G). No patient was homozygous for UGT1A1*28, and none had UGT1A1*27. Two were heterozygous for UGT1A1*28. Two were homozygous and 15 heterozygous for UGT1A1*6, all of whom were wild type with respect to UGT1A1*28. Two patients were simultaneously heterozygous for UGT1A1*28 and UGT1A1*6, present on different chromosomes. The other 25 patients had none of the variants studied. The two patients simultaneously heterozygous for UGT1A1*28 and UGT1A1*6 and the two patients homozygous for UGT1A1*6 had significantly higher AUCSN‐38/AUCSN‐38G ratios than the others (P = 0.0039). Concurrence of UGT1A1*28 and UGT1A1*6, even when heterozygous, altered the disposition of irinotecan remarkably, potentially increasing susceptibility to toxicity. Patients homozygous for UGT1A1*6 should also be carefully monitored. UGT1A1 polymorphisms in the coding region of the UGT1A1 gene should be genotyped in addition to testing for UGT1A1*28 to more accurately predict irinotecan‐related toxicity, at least in Asian patients. (Cancer Sci 2006; 97: 1255–1259)

Comparison of the Efficacy, Toxicity, and Pharmacokinetics of a Uracil/Tegafur (UFT) Plus Oral Leucovorin (LV) Regimen Between Japanese and American Patients With Advanced Colorectal Cancer: Joint United States and Japan Study of UFT/LV

PURPOSE To compare the efficacy, toxicities, and pharmacokinetics of an oral regimen consisting of uracil/tegafur (UFT) and leucovorin (LV) between Japanese patients and patients in the United States with previously untreated metastatic colorectal cancer. PATIENTS AND METHODS Forty-four Japanese patients and 45 patients in the United States were enrolled in concurrent nonrandomized phase II trials. UFT 300 mg/m2/d and leucovorin 75 mg/d were administered orally for 28 days followed by a 7-day rest period. The total daily dose of each drug was divided into three equal doses. Treatment was repeated every 5 weeks until disease progression. Blood samples for the pharmacokinetic study were obtained after the initial dose on day 1 of the first course. RESULTS The response rate for the Japanese patients and the patients in the United States was 36.4% (95% CI, 22.4% to 52.2%) and 34.1% (95% CI, 20.5% to 49.9%), respectively. The only major toxicity was diarrhea, and other toxicities were mild in both populations. The incidence of grade 3 or higher diarrhea in the Japanese and Americans was 9% and 22%, respectively. Although the area under the curve and maximum concentration of fluorouracil were found to be slightly higher in the Japanese patients than the patients in the United States, and area under the curve-adjusted body surface area appeared to be comparable between the two groups. CONCLUSION The efficacy and pharmacokinetic parameters of UFT and LV are comparable in Japanese and American patients; however, a difference in toxicity profile, specifically diarrhea, was noted. This oral regimen of UFT and LV is considered to have similar activity against metastatic colorectal cancer and to have acceptable toxicity in patients in both countries.

Thymidylate Synthase Haplotype is Associated with Tumor Recurrence in Stage II and Stage III Colon Cancer Patients

Background Tumor recurrence after curative resection is a major problem in the management of colon cancer therapy. Identifying molecular markers for tumor recurrence is critical for successfully selecting patients who are more likely to benefit from adjuvant chemotherapy. We analyzed the value of thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms as a prognostic marker in stage II and stage III colon cancer patients treated with 5-fluorouracil-based adjuvant chemotherapy. Methods Between 1987 and 2007, blood samples were obtained from 197 patients with stage II or stage III colon cancer at medical facilities at the University of Southern California. DNA was extracted from peripheral blood, and the genotypes were analyzed using PCR–restriction fragment length polymorphism technique. Results Patients harboring the TS 3RG/+6-bp haplotype were at greatest risk to develop tumor recurrence [relative risk (RR): 2.25; 95% confidence interval (CI): 1.04–4.85; adjusted P value=0.032]. TS enhancer region 3RG alone (RR: 3.48 years; 95% CI: 1.61–7.54; adjusted P value=0.013) or in combination with TS 1494del6 bp (RR: 3.41 years; 95% CI: 1.33–8.75; adjusted P value=0.044) proved to be adverse prognostic markers in both univariate and multivariable analysis. Conclusion ‘High-expression’ variants of TS 2R/3R repeat, TS enhancer region 3R G/C, TS 1494del6 bp, and TS haplotype analysis might help to identify stage II and stage III colon cancer patients who are at great risk of developing tumor recurrence, and also those who are more likely to benefit from 5-fluorouracil-based adjuvant chemotherapy. Larger, independent, prospective studies are, however, needed to confirm and validate our preliminary findings.

Japanese nationwide post-marketing survey of S-1 in patients with advanced gastric cancer.

BackgroundIt is likely that there are some discrepancies in the safety and efficacy results for anticancer agents between those shown in registration studies for approval and those shown in clinical practice after market release. The aim of this survey was to confirm the safety and efficacy of S-1 for advanced gastric cancer after market release.MethodsAfter the approval of S-1 in 1999, all patients had to be registered with the manufacturer for a post-marketing survey, according to the government recommendation. All patients were monitored for safety and survival. The data for all registered patients were updated 1 year after each registration.ResultsDuring this survey, a total of 4177 patients with advanced gastric cancer were registered. The incidences of all adverse events and of grade 3 or worse adverse events in the 3808 patients evaluable for safety were 74.3% and 25.0%, respectively. In patients with lower creatinine clearance at baseline, the incidences of adverse reactions were higher for all grades combined, as well as for grades 3 or worse. There were 90 (2.4%) early deaths (within 30 days of the initiation of the treatment) and 5 (0.1%) deaths possibly related to the treatment. The median survival time and the 1-year survival rate for all patients evaluable for efficacy (n 5 3801) were 8.3 months (95% confidence interval [CI], 8.0–8.6 months) and 33.3% (95% CI, 31.8–34.9%), respectively.ConclusionThis nationwide survey confirmed that the safety and efficacy profiles of S-1 were similar to those seen in the registration study. These results have proven the utility of this post-marketing survey in assessing the reproducibility of the safety and efficacy results obtained from prior clinical studies.

CYP2A6 and the plasma level of 5-chloro-2, 4-dihydroxypyridine are determinants of the pharmacokinetic variability of tegafur and 5-fluorouracil, respectively, in Japanese patients with cancer given S-1

S‐1 is an oral anticancer agent composed of tegafur (FT), 5‐chloro‐2,4‐dihydroxypyridine (CDHP), and potassium oxonate. CDHP is added to prevent degradation of 5‐fluorouracil (5‐FU) by inhibiting dihydropyrimidine dehydrogenase. CYP2A6 is involved in the biotransformation of FT to 5‐FU. Thus, we prospectively analyzed the effects of the CYP2A6 genotype, plasma level of CDHP, and patient characteristics on the pharmacokinetic (PK) variability of FT and 5‐FU. Fifty‐four Japanese patients with metastatic or recurrent cancers who received S‐1 were enrolled. The CYP2A6 polymorphisms (*4A, *7, and *9) with deficient or reduced activity were analyzed. All subjects were classified into three groups according to their CYP2A6 genotype: wild type (*1/*1), one‐variant allele (*1/any), or two‐variant alleles (combination other than *1). The PK of FT, 5‐FU, and CDHP were measured on day 1 of treatment. Multivariate regression analysis revealed that oral clearance of FT was associated with the CYP2A6 genotype (analysis of variance [ANOVA], P = 0.000838). The oral clearance of FT seen in patients with the two‐variant alleles was significantly lower than those in wild type and the one‐variant allele (95% confidence intervals 0.75–2.41 and 0.41–1.82, respectively; Tukey‐Kramer test). The area under the time–concentration curve (AUC) of 5‐FU was significantly correlated with the AUC of CDHP (ANOVA, P = 0.00126). The AUC of 5‐FU and CDHP were inversely correlated with creatinine clearance (ANOVA, P = 0.0164 and P = 0.000762, respectively). Although the CYP2A6 variants are the cause of the PK variability of FT, the AUC of CDHP affected by renal function is the key determinant of the variability in the PK of 5‐FU. (Cancer Sci 2008; 99: 1049–1054)

Genetic testing for UGT1A1*28 and *6 in Japanese patients who receive irinotecan chemotherapy

Polymorphisms of the UDP-glucuronosyltransferase (UGT) 1A1 gene, such as UGT1A1*28 and UGT1A1*6, can cause severe neutropenia and diarrhea in patients who receive irinotecan [1, 2]. Homozygosity for UGT1A1*28 is associated with less efficient glucuronidation of SN-38, the active metabolite of irinotecan, resulting in increased plasma SN-38 concentrations. Four pharmacogenetic trials have demonstrated an association between UGT1A1*28 genotype and irinotecan-induced hematologic toxicity, diarrhea, or both [3]. In response to these findings, the United States Food and Drug Administration has approved genetic testing for UGT1A1*28 and recommends that the initial dose of irinotecan is reduced by at least one level in patients who are homozygous for UGT1A1*28, albeit the effectiveness of such testing remains to be confirmed prospectively. UGT1A1*6 is also associated with severe irinotecan-related toxicity [4]. Given that the area under the time versus concentration curve ratio (SN-38 glucuronide/SN-38) seen in patients homozygous for UGT1A1*28 and *6 are almost equal [4], the impact of these variants on glucuronidation capacity of UGT1A1 for SN-38 is almost the same. The distribution of genotypes associated with these polymorphisms varies considerably among ethnic groups. UGT1A1*28 is found in Japanese and whites, but the allele frequency in Japanese is lower than that in whites [2, 4]. UGT1A1*6 is found in Japanese, but not in whites [4]. Homozygosity for UGT1A1*28 or UGT1A1*6 and heterozygosity for both UGT1A1*6 and UGT1A1*28 are associated with severe irinotecan-related neutropenia in Japanese patients [1, 4]. The Ministry of Health, Labour and Welfare in Japan has therefore recently approved genetic testing for UGT1A1*28 and *6. The value of genetic testing for UGT1A1 depends on genotype frequency and the association of genetic variants with irinotecan-induced toxicity. The higher the frequency of toxicity-related polymorphisms, the greater is the number of patients who would benefit from genetic testing. Large prospective studies are needed to accurately estimate the distribution of UGT1A1 polymorphisms in a given population. We have carried out the largest prospective study to date, examining the distributions of UGT1A1*28 and UGT1A1*6 genotypes in 300 Japanese patients (male/female, 172 of 128) with various solid tumors (200 colorectal, 43 gastric, 15 ovarian, 14 breast, 10 lung, and 18 others). All patients gave written informed consent, and the study protocol was approved by the Institutional Review Board of Saitama Medical University. Genotyping was carried out as described elsewhere [5]. UGT1A1*28 and UGT1A1*6 were in Hardy–Weinberg equilibrium (P > 0.05). Only 2 of 300 patients were UGT1A1*28 homozygotes (0.7%) (Table 1). The frequency of homozygosity for UGT1A1*28 was much lower than that in other prospective studies in Japan (2.3%, 4 of 176) [4]. The frequency of UGT1A1*6 homozygosity was 5.7% (Table 1), higher than that reported previously (2.8%) [4]. Eleven patients were both heterozygous for UGT1A1*6 and UGT1A1*28 (3.7%). The combined frequency of patients with two ‘risk alleles’ (i.e. *28/*28, *6/*6, and *6/*28) was 10.1% (95% confidence interval, 6.8% to 14.0%). Such patients might be at increased risk for irinotecan-related neutropenia. Given the genotype frequencies of UGT1A1*28 and UGT1A1*6, genetic testing for UGT1A1 might not be essential for identifying homozygotes for UGT1A1*28, but useful for identifying homozygotes for UGT1A1*6 as well as heterozygotes for UGT1A1*6 and UGT1A1*28, thereby avoiding severe irinotecan-induced toxicity in Japanese patients. The present results and considerations are likely to have application across East Asia. Prospective evaluations of genetic testing for UGT1A1 polymorphisms, encompassing both medical aspects and cost effectiveness, appear to be warranted, especially in East Asian countries including Japan. Table 1. Genotype frequencies of UGT1A1*28 and UGT1A1*6 in Japanese

Role of chemotherapy in treatments for biliary tract cancer

The purpose of chemotherapy in patients with advanced solid cancers, including biliary tract cancer, is generally to improve the survival and quality of life of the patients. Also, adjuvant chemotherapy is expected to increase the curability of surgery in patients scheduled to undergo surgery. Most patients with unresectable biliary tract cancer develop obstructive jaundice, and biliary drainage is needed before any of the aforementioned treatments. Once jaundice is resolved by stenting of the bile duct or bilio-intestinal bypass, cholangitis often develops, leading to rapid deterioration of the patient’s general condition. Therefore, the beneficial effect of chemotherapy in such patients remains controversial. A few randomized controlled trials have demonstrated the survival benefit of chemotherapy as compared with supportive care. In one of these trials, improvement of the quality of life was also confirmed. Recently, since the survival benefit of combined gemcitabine plus cisplatin therapy over gemcitabine alone has been demonstrated in randomized controlled clinical trials, this combined regimen has been recognized as a standard therapy for unresectable biliary tract cancer. A second-line regimen is now expected to be established for patients with gemcitabine-refractory biliary tract cancer, although the significance of second-line therapy remains unclear. One of the next issues in relation to chemotherapy for biliary tract cancer is the development of molecular-targeted agents; however, few large clinical trials of such agents have been conducted for biliary tract cancer. Various issues in chemotherapy for biliary tract cancer remain to be investigated, and global cooperation is necessary to conduct large clinical trials.