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Background: Presently, few options are available for refractory colorectal cancer (CRC). O6-methyl-guanine-DNA-methyltransferase (MGMT) promoter methylation is a frequent and early event in CRC tumourigenesis. This epigenetic silencing is a predictor of response to the alkylating drug temozolomide in glioblastoma. Preclinical evidences and some case reports showed temozolomide activity in CRC with MGMT silencing, but the available data from clinical trials are inconsistent.Methods: This was a multicentre, phase 2 trial, planned according to a two-stage Simon's optimal design to investigate activity and safety of temozolomide in refractory CRC harbouring MGMT promoter methylation. The primary end point was overall response rate (ORR). Patients who failed two or more prior treatments received temozolomide at a dose of 150-200 mg m-2 per day on days 1-5 every 28 days.Results: From July 2012 to June 2016, 225 patients were screened, 80 showed MGMT promoter methylation and 41 were enrolled. Overall response rate was 10% and disease control rate was 32%. Median progression-free survival and overall survival were 1.9 and 5.1 months, respectively.Conclusions: Temozolomide showed a modest activity in this heavily pretreated population and the study did not meet its primary end point. The role of temozolomide in CRC remains still controversial and further research is warranted. [ABSTRACT FROM AUTHOR]

Background:In this study, we evaluated the possibility that KRAS mutational status might be predictive of oxaliplatin (OXA) efficacy. We also explored the role of excision repair cross complementing group-1 (ERCC-1).Methods:Ninety anti-epidermal growth factor receptor-naive advanced colorectal cancer patients were retrospectively analysed. In all patients KRAS mutational status was assessed. In 60 patients mRNA ERCC-1 expression was also investigated. Response rate (RR) and progression-free survival (PFS) after FOLFOX-6±bevacizumab were evaluated according to KRAS status and mRNA ERCC-1 expression.Results:Among 90 patients 47% wild-type (wt) and 53% mutated (mt) KRAS tumours were found. Response rate was 26% in the wt KRAS group, whereas it was 56% in the mt KRAS group; the difference is statistically significant in the total sample (P=0.008) and when only patients receiving FOLFOX-6±bevacizumab as first-line are considered (P=0.01). Progression-free survival was longer in mt than in wt KRAS patients over all patients (10 vs 8 months, respectively, P=0.001) and in those treated as first-line (10 vs 8 months, respectively, P=0.0069). Mt KRAS patients experienced a longer survival (24 vs 18 months; P=0.01). ERCC-1 mRNA expression was not found to correlate with FOLFOX activity in our analysis.Conclusion:Our results suggest that activating mutation of KRAS oncogene may predict response to OXA. Basal expression of ERCC-1 mRNA does not explain the high efficacy of FOLFOX-6 in mt KRAS patients. [ABSTRACT FROM AUTHOR]