Eugenio Marcuello

UGT1A1 gene variations and irinotecan treatment in patients with metastatic colorectal cancer

SN-38 is the active metabolite of irinotecan and it is metabolised through conjugation by uridine diphosphate glucuronosyl transferase (UGT1A1). The major toxicity of irinotecan therapy is diarrhoea, which has been related to the enzymatic activity of UGT1A1. We examined the influence of the UGT1A1 gene promoter polymorphism in the toxicity profile, in the response rate and in the overall survival (OS) in 95 patients with metastatic colorectal cancer treated with an irinotecan-containing chemotherapy. Genotypes were determined by analysing the sequence of TATA box of UGT1A1 of genomic DNA from the patients. Clinical parameters and genotypes were compared by univariate and multivariate statistical methods. The more frequent adverse effects were asthenia (34 patients), diarrhoea (29 patients) and neutropenia (20 patients). Severe diarrhoea was observed in 7/10 homozygous (70%) and 15/45 heterozygous (33%) in comparison to 7/40 (17%) wild-type patients (P=0.005). These results maintained the statistical significance in logistic regression analysis (P=0.01) after adjustment for other clinical relevant variables. The presence of severe haematological toxicity increased from wild-type patients to UGT1A1*28 homozygotes, but without achieving statistical significance. No relationship was found between the UGT1A1*28 genotypes and infection, nausea or mucositis. In univariate studies, patients with the UGT1A1*28 polymorphism showed a trend to a poorer OS (P=0.09). In the multivariate analysis, the genotype was not related to clinical response or to OS. The role of the UGT1A1 genotype as a predictor of toxicity in cancer patients receiving irinotecan demands the performance of a randomized trial to ascertain whether genotype-adjusted dosages of the drug can help to establish safe and effective doses not only for patients with the UGT1A1*28 homozygous genotype but also for those with the most common UGT1A1 6/6 or 6/7 genotype.

Phase II, randomized study of concomitant chemoradiotherapy followed by surgery and adjuvant capecitabine plus oxaliplatin (CAPOX) compared with induction CAPOX followed by concomitant chemoradiotherapy and surgery in magnetic resonance imaging-defined, locally advanced rectal cancer: Grupo cancer de recto 3 study.

PURPOSE The optimal therapeutic sequence of the adjuvant chemotherapy component of preoperative chemoradiotherapy (CRT) for patients with locally advanced rectal cancer is controversial. Induction chemotherapy before preoperative CRT may be associated with better efficacy and compliance. PATIENTS AND METHODS A total of 108 patients with locally advanced rectal cancer were randomly assigned to arm A-preoperative CRT with capecitabine, oxaliplatin, and concurrent radiation followed by surgery and four cycles of postoperative adjuvant capecitabine and oxaliplatin (CAPOX)-or arm B-induction CAPOX followed by CRT and surgery. The primary end point was pathologic complete response rate (pCR). Results On an intention-to-treat basis, the pCR for arms A and B were 13.5% (95% CI, 5.6% to 25.8%) and 14.3% (95% CI, 6.4% to 26.2%), respectively. There were no statistically significant differences in other end points, including downstaging, tumor regression, and R0 resection. Overall, chemotherapy treatment exposure was higher in arm B than in arm A for both oxaliplatin (P < .0001) and capecitabine (P < .0001). During CRT, grades 3 to 4 adverse events were similar in both arms but were significantly higher in arm A during postoperative adjuvant CT than with induction CT in arm B. There were three deaths in each arm during the treatment period. CONCLUSION Compared with postoperative adjuvant CAPOX, induction CAPOX before CRT had similar pCR and complete resection rates. It did achieve more favorable compliance and toxicity profiles. On the basis of these findings, a phase III study to definitively test the induction strategy is warranted.

K-ras and p16 Aberrations Confer Poor Prognosis in Human Colorectal Cancer

PURPOSE Mutations in the K-ras gene are frequent in human cancer. ras activation in primary cells results in a cellular senescence phenotype that is precluded by inactivation of p16. At the clinical level, this may imply a differential behavior for tumors with alternative or cooperative activation of K-ras function and impairment of p16 pathways. PATIENTS AND METHODS We have determined the presence of mutations in the K-ras gene and the methylation status of p16 promoter in a series of 119 prospectively collected colorectal carcinomas. p53 mutations and p14 alternative reading frame methylation status were also assessed. Associations with survival were investigated. RESULTS K-ras mutations were present in 44 (38%) of 115 cases, and p16 methylation was present in 42 (37%) of 113 cases. p53 mutations were detected in 50% (56 of 115) and p14 methylation in 29% (32 of 112) of cases. K-ras and p16 alterations were independent genetic events. Presence of K-ras or p16 genetic alterations (analyzed independently) was associated with shorter survival, although differences were not statistically significant. Cox analysis of the two variables combined showed a diminished survival as the results of an interaction between p16 and K-ras. Alternative alteration of K-ras and p16 genes was an independent prognostic factor in human colorectal cancer in univariate and multivariate analysis. Differences were maintained when cases undergoing radical surgery and without distant metastases were considered. CONCLUSION These results suggest that the combined K-ras and p16 analyses may be of prognostic use in human colorectal cancer.

p53 and K-ras Gene Mutations Correlate With Tumor Aggressiveness But Are Not of Routine Prognostic Value in Colorectal Cancer

PURPOSE p53 gene and K-ras mutations are among the most common genetic alterations present in colorectal cancer. The prognostic utility of such mutations remains controversial. The purpose of this study was to prospectively evaluate the prognostic significance of p53 and K-ras gene mutations in colorectal cancer. PATIENTS AND METHODS One hundred forty patients were analyzed. Tumors belonging to the microsatellite mutator phenotype were excluded (n = 8). Mutations at the K-ras and p53 genes were detected and characterized by restriction fragment length polymorphism, single-strand conformation polymorphism, and sequencing, as appropriate. RESULTS p53 mutations were detected in 66 (50%) and K-ras mutations were detected in 54 (41%) of the 132 patients. In 26 cases (20%), ras and p53 mutations coexisted; in 38 cases (29%), neither mutation was found. Multivariate analysis of the whole population analyzed (n = 132) showed that survival was strongly correlated with the presence of p53 mutations alone or in combination with K-ras mutations (P = .002; log-rank test). When only patients undergoing a radical resection were considered (R0; n = 101), p53 mutations were no longer of prognostic significance. CONCLUSION p53 mutations alone or in combination with K-ras mutations are correlated with a worse outcome. However, the routine use of these mutations as prognostic markers in the clinical setting is not recommended.

Single nucleotide polymorphism in the 5′ tandem repeat sequences of thymidylate synthase gene predicts for response to fluorouracil‐based chemotherapy in advanced colorectal cancer patients

Thymidylate synthase (TS) is the primary target of 5‐fluorouracil (5‐FU). A VNTR polymorphism in the TS promoter region is associated with the efficacy of 5‐FU‐based chemotherapy in colorectal cancer. A common G>C SNP at the 12th nucleotide of the second repeat in the TS*3 alleles has been recently described. The combination of SNP and VNTR allows the definition of 3 TS alleles: *2, *3G and *3C. The aim of our study was to evaluate the predictive value of clinical response and survival of these new defined TS alleles. TS genotypes of 89 patients diagnosed with metastatic colorectal cancer and undergoing 5‐FU‐based chemotherapy were carried out. The clinical outcome was evaluated according to the genotype (high expression genotype: *2R/*3G; *3C/*3G; *3G/*3G; and low expression genotype: *2R/*2R; *2R/*3C; *3C/*3C. A higher overall response was observed in the group of patients with a low expression genotype (p = 0.035). The probability of achieving a clinical response of patients with a low expression‐related genotype was 2.9 higher than that of the other group (95% CI = 1.03–5.6, p = 0.04). The median time to progression was 12 months and 9 months in the low and high expression groups, respectively (p = 0.07, log rank test). Overall survival was significantly longer in the low expression group. In this group the median OS was not achieved at 50 months of follow‐up in contrast to the 20 months observed in the high expression group (p = 0.03). TS genotype was an independent predictor of progression‐free and overall survival in the Cox regression models after adjustment to the other clinical variables. The selection of patients who are likely to respond to 5‐FU therapy may be considerably improved if the TS genotype were to include both the VNTR and the SNP located within the promoter region of the gene.

Pharmacogenetic prediction of clinical outcome in advanced colorectal cancer patients receiving oxaliplatin/5-fluorouracil as first-line chemotherapy.

To determine whether molecular parameters could be partly responsible for resistance or sensitivity to oxaliplatin (OX)-based chemotherapy used as first-line treatment in advanced colorectal cancer (CRC). We studied the usefulness of the excision repair cross-complementing 1 (ERCC1), xeroderma pigmentosum group D (XPD), XRCC1 and GSTP1 polymorphisms as predictors of clinical outcome in these patients. We treated 126 CRC patients with a first-line OX/5-fluorouracil chemotherapeutic regimen. Genetic polymorphisms were determined by real-time PCR on an ABI PRISM 7000, using DNA from peripheral blood. Clinical response (CR), progression-free survival (PFS) and overall survival (OS) were evaluated according to each genotype. In the univariate analysis for CR, ERCC1-118 and XPD 751 polymorphisms were significant (P=0.02 and P=0.05, respectively). After adjustment for the most relevant clinical variables, only ERCC1-118 retained significance (P=0.008). In the univariate analysis for PFS, ERCC1-118 and XPD 751 were significant (P=0.003 and P=0.009, respectively). In the multivariant analysis, only the XPD 751 was significant for PFS (P=0.02). Finally, ERCC1-118 and XPD 751 polymorphisms were significant in the univariate analysis for OS (P=0.006 and P=0.015, respectively). Both genetic variables remained significant in the multivariate Cox survival analysis (P=0.022 and P=0.03). Our data support the hypothesis that enhanced DNA repair diminishes the benefit of platinum-based treatments.

Irinotecan in Combination With Fluorouracil in a 48-Hour Continuous Infusion As First-Line Chemotherapy for Elderly Patients With Metastatic Colorectal Cancer: A Spanish Cooperative Group for the Treatment of Digestive Tumors Study

PURPOSE Elderly patients constitute a subpopulation with special characteristics that differ from those of the nonelderly and have been underrepresented in clinical trials. This study was performed to determine the efficacy and safety of irinotecan (CPT-11) in combination with fluorouracil (FU) administered as a 48-hour continuous infusion twice a month in elderly patients. PATIENTS AND METHODS Patients > or = 72 years old with metastatic colorectal cancer, Eastern Cooperative Oncology Group performance status of 0 to 1, no geriatric syndromes, and no prior treatment were treated every 2 weeks with CPT-11 180 mg/m2 plus FU 3,000 mg/m2 in a 48-hour continuous infusion. RESULTS By intent-to-treat analysis, in 85 assessable patients, the objective response rate was 35% (95% CI, 25% to 46%), and stable disease was 33% (95% CI, 23% to 44%). Median time to progression was 8.0 months (95% CI, 6.0 to 10.0 months), and median overall survival time was 15.3 months (95% CI, 13.8 to 16.9 months). Toxicity was moderate. Grade 3 and 4 neutropenia, diarrhea, and asthenia were observed in 21%, 17%, and 13% of patients, respectively. Only one case of neutropenic fever occurred. There were two toxic deaths, one was a result of grade 4 diarrhea and acute kidney failure, and the other was a result of massive intestinal hemorrhage in the first cycle. The study of prognostic factors did not reveal any predictive factor of response. Response to treatment and baseline lactate dehydrogenase were the main factors conditioning progression-free and overall survival. CONCLUSION Twice a month continuous-infusion CPT-11 combined with FU is a valid therapeutic alternative for elderly patients in good general condition.

Methylenetetrahydrofolate reductase gene polymorphisms: genomic predictors of clinical response to fluoropyrimidine-based chemotherapy?

Fluorouracil (5-FU) is widely used in the treatment of colorectal cancer. Methylenetetrahydrofolate reductase (MTHFR) may play a central role in the action of 5-FU, an inhibitor of thymidylate synthase, by converting 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. The aim of this study was to ascertain whether two polymorphisms in the MTHFR gene (677C>T and 1298 A>C) could be used as genomic predictors of clinical response to fluoropyrimidine-based chemotherapy (in combination with irinotecan or oxaliplatin). Ninety-four patients diagnosed with metastatic colorectal cancer and undergoing 5-FU-containing chemotherapy as a first line treatment were studied. The results suggest that the MTHFR genotype cannot be considered as an independent factor of outcome in colorectal cancer patients under 5-FU-based chemotherapy.

UGT1A and TYMS genetic variants predict toxicity and response of colorectal cancer patients treated with first-line irinotecan and fluorouracil combination therapy.

Background:The impact of thymidylate synthase (TYMS) and UDP-glucoronosyltransferase 1A (UGT1A) germline polymorphisms on the outcome of colorectal cancer (CRC) patients treated with irinotecan plus 5-fluorouracil (irinotecan/5FU) is still controversial. Our objective was to define a genetic-based algorithm to select patients to be treated with irinotecan/5FU.Methods:Genotyping of TYMS (5′TRP and 3′UTR), UGT1A1*28, UGT1A9*22 and UGT1A7*3 was performed in 149 metastatic CRC patients treated with irinotecan/5FU as first-line chemotherapy enrolled in a randomised phase 3 study. Their association with response, toxicity and survival was investigated by univariate and multivariate statistical analysis.Results:TYMS 3TRP/3TRP genotype was the only independent predictor of tumour response (OR=5.87, 95% confidence interval (CI)=1.68–20.45; P=0.005). UGT1A1*28/*28 was predictive for haematologic toxicity (OR=6.27, 95% CI=1.09–36.12; P=0.04), specifically for neutropenia alone (OR=6.40, 95% CI=1.11–37.03; P=0.038) or together with diarrhoea (OR=18.87, 95% CI=2.14–166.67; P=0.008). UGT1A9*1/*1 was associated with non-haematologic toxicity (OR=2.70, 95% CI=1.07–6.82; P=0.035). Haplotype VII (all non-favourable alleles) was associated with non-haematologic toxicity (OR=2.11, 95% CI=1.12–3.98; P=0.02).Conclusion:TYMS and UGT1A polymorphisms influence on tumour response and toxicities derived from irinotecan/5FU treatment in CRC patients. A genetic-based algorithm to optimise treatment individualisation is proposed.

A genotype-directed phase I-IV dose-finding study of irinotecan in combination with fluorouracil/leucovorin as first-line treatment in advanced colorectal cancer.

Background:Infusional fluorouracil/leucovorin (FU/LV) plus irinotecan (FOLFIRI) is one of the standard first-line options for patients with metastatic colorectal cancer (mCRC). Irinotecan is converted into 7-ethyl-10-hydroxycamptothecin (SN-38) by a carboxylsterase and metabolised through uridine diphosphate glucuronosyl transferase (UGT1A1). The UGT1A1*28 allele has been associated with the risk of developing severe toxicities. The present trial was designed to define the maximum tolerated dose according to UGT1A1 genotype. This report focuses on the results of tolerance to different escalated doses of FOLFIRI first-line of chemotherapy.Patients and methods:Patients undergoing first-line treatment for mCRC and eligible for treatment with FOLFIRI were classified according to UGT1A1 genotype. A total of 94 patients were eligible for dose escalation of irinotecan. The starting dose of biweekly irinotecan was 180 mg m−2 for the *1/*1, 110 mg m−2 for the *1/*28 and 90 mg m−2 for the *28/*28 genotypes.Results:The dose of irinotecan was escalated to 450 mg m−2 in patients with the *1/*1 genotype, to 390 mg m−2 in those with the *1/*28 genotype and to 150 mg m−2 in those with the *28/*28 genotype. Neutropenia and diarrhoea were the most common grade 3 or 4 toxicities.Conclusions:Our results demonstrated that the recommended dose of 180 mg m−2 for irinotecan in FOLFIRI is considerably lower than the dose that can be tolerated for patients with the UGT1A1 *1/*1 and *1/*28 genotypes. The maximum tolerable dose (MTD) in patients with a high-risk UGT1A1 *28/*28 genotype is 30% lower than the standard dose of 180 mg m−2.