A Pharmacogenomic Study of Docetaxel and Gemcitabine for the Initial Treatment of Advanced Non-Small Cell Lung Cancer
Pharmacogenomic profiling is an attractive strategy for individualizing chemotherapy. Several genetic polymorphisms predict the survival of patients with non-small cell lung cancer treated with platinum-based chemotherapy. This phase II clinical trial was performed using a non-platinum-based chemotherapy doublet. The impact of previously identified polymorphisms on clinical outcomes was assessed.
Patients with advanced non-small cell lung cancer who had not received previous chemotherapy were treated with docetaxel 40 mg/m2 on days 1 and 8 and gemcitabine 800 mg/m2 days 1 and 8 every 21 days until disease progression or unacceptable toxicity. A pretreatment blood sample was obtained, and genomic DNA was analyzed for polymorphisms in DNA repair and metabolic genes.
Forty-nine patients were enrolled and evaluated for response and survival. The overall radiographic response rate was 38%, and the median survival was 8.6 months. Nonhematologic toxicity was generally mild. Two treatment related deaths occurred: one due to neutropenic sepsis during the first cycle and one due to pulmonary edema after 12 cycles of treatment. Polymorphisms in XPD, XRCC1, and XRCC3 did not significantly predict survival, but trends similar to those reported for platinum-based chemotherapy were observed. The wild-type XPD genotype was associated with prolonged survival and a significantly higher risk of grade 4 neutropenia (p = 0.02).
This regimen of docetaxel and gemcitabine is well tolerated and active for the treatment of advanced non-small cell lung cancer. The impact of XPD polymorphisms on hematologic toxicity is similar to what has been reported for platinum-based chemotherapy.
Available from: Sukru Tuzmen
- "Association between tumor expression level of SLC29A1 [Kim, 1999; Myers et al., 2006], ERCC1 [Bepler et al., 2006], and DCK [Mey et al., 2006; Shi et al., 2004] and clinical outcomes in patients treated with gemcitabine has been reported. Genetic variations in CDA [Gilbert et al., 2006; Sugiyama et al., 2007; Yonemori et al., 2005], DCTD [Gilbert et al., 2006], ERCC2 (XPD) [Camps et al., 2003; Petty et al., 2007], and XRCC3 [de las Penas et al., 2006] genes were implicated to have association or trend with response, toxicity, or survival in gemcitabine-treated patients. SNPs in RECQL, RAD54L, XRCC1, and ATM were investigated in patients treated with gemcitabine and were found to have significant effects on overall survival [Li et al., 2006]. "
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ABSTRACT: Chemotherapy is a major treatment modality for individuals affected by cancer. Currently, a number of genome-based technologies are being adopted to identify genes associated with drug response; however, large-scale genetic association applications are still limited. Here we describe a novel strategy based on the genetic and drug response data of the NCI60 cell lines to discover potential candidate genetic variants associated with variable response to chemotherapy. As an example we have applied this strategy to discover single genetic markers and haplotypes from candidate genes previously implicated in the pharmacobiology of gemcitabine. Single-marker association analyses have implicated the association of four SNPs within the gene loci of CDC5L, EPC2, POLS, and PARP1. We have also investigated the combined effect of SNPs using haplotype-based analysis. Accordingly, we have shown modest association of haplotypes in six genes, whereas the most significant associations included a haplotype of the POLS gene. The hypothesis-generating tool presented in this study can be applied to drugs profiled in the NCI60 cell line screen and provides an effective means for the identification of genes associated with drug response. The results obtained using this novel methodology can be used to better design the clinical trials for effective study of the chemotherapeutic agents and thus provide a basis for individualized chemotherapy.
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To investigate whether polymorphisms in ERCC1, XPD, XPG, XRCC1 genes are associated with clinical outcomes in advanced gastric cancer (AGC) patients treated with oxaliplatin-based chemotherapy.
The genetic polymorphisms in ERCC1, XPD, XPG, XRCC1 were determined in 94 advanced gastric cancer patients treated with oxaliplatin-based chemotherapy, using TaqMan-MGB probes. The clinical response of 60 patients with stage IV disease, time to progression (TTP) and overall survival (OS) of 94 patients were evaluated.
The overall disease control rate (CR + PR + SD) of the 60 patients in stage IV was 70% (42/60). Patients with XRCC1 399 G/G, XPG 46 C/C genotypes showed enhanced response to the oxaliplatin-based chemotherapy compared to those with other genotypes (P < 0.05). The median OS and TTP of the patients were 5.5 months and 9.0 months, respectively. Among the 4 types of polymorphisms in the study, XRCC1 399 G/A + A/A, XPG 46 C/T + T/T genotypes were regarded to be associated with chemoresistance and poor survival (P < 0.05). Combination analysis of the 2 polymorphisms using the Kaplan-Meier method revealed that the TTP and OS of the patients with a number of risk genotypes were significantly shortened (P < 0.05). No significant association was found between the genotypes of the XPD codon 751, the ERCC1 codon 118 and the clinical outcome (P > 0.05).
Testing for XRCC1 399, XPG 46 polymorphisms may allow identification of the gastric cancer patients who will benefit from oxaliplatin-based chemotherapy. Specific polymorphisms may influence clinical outcomes of AGC patients. Selecting specific chemotherapy based on pretreatment genotyping represents an innovative strategy that warrants prospective studies.
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ABSTRACT: The evolving field of cancer pharmacogenomics uses genetic profiling to predict the response of tumor and normal tissue to therapy. The narrow therapeutic index and heterogeneity of patient responses to chemotherapy and radiotherapy implies that the efficacy of these treatments could, potentially, be significantly enhanced by improving our understanding of the genetic bases for interindividual differences in their effects. The cytotoxicity of both chemotherapy and radiotherapy is to a large extent directly related to their ability to induce DNA damage. The ability of cancer cells to recognize and repair this damage contributes to therapeutic resistance. On the other hand, suboptimal DNA repair in normal tissue may negatively impact on normal tissue tolerance.
More than 130 genes have been identified that are associated with human DNA repair, and single nucleotide polymorphisms of several of the DNA repair genes have been described recently. In this article, we present the current evidence implicating variations within DNA repair genes as important predictive and prognostic markers in cancer. We review evidence suggesting DNA repair genetic polymorphisms may significantly influence the clinical response to chemotherapy and radiotherapy, and may influence normal tissue tolerance to cancer treatments.
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