Pharmacogenetic analyses of a phase III trial in metastatic gastroesophageal adenocarcinoma with fluorouracil and leucovorin plus either oxaliplatin or cisplatin: a study of the arbeitsgemeinschaft internistische onkologie.

PURPOSE: To evaluate the association of germ-line polymorphisms of genes that may impact treatment outcome of platinum and fluorouracil combination chemotherapy in advanced gastric cancer (AGC). PATIENTS AND METHODS: Blood samples of 156 patients enrolled onto a phase III study comparing fluorouracil, leucovorin, and oxaliplatin with fluorouracil, leucovorin, and cisplatin were collected. Polymorphisms within genes of TS, MTHFR, MTR, OPRT, XPD, ERCC1, XRCC1, XPA, GSTP1, GSTT1, and GSTM1 were genotyped using polymerase chain reaction-based techniques. RESULTS: Median overall survival (OS) was 11.8 months (95% CI, 9.75 to 13.79 months) and median progression-free survival (PFS) was 5.8 months (95% CI, 4.99 to 6.61 months). The TS-3R/+6 haplotype (P = .004), the GSTT1 deletion polymorphism (P = .015), and genotypes of OPRT-Gly213Ala (P = .003) and XRCC1-Arg399Gln (P = .023) could be identified as independent predictors of OS. For PFS analyses, the TS-3R/+6 haplotye (P = .003) and MTR-A2756G (P = .01) were identified as independent positive predictors. The association between the GSTT1 deletion polymorphism and PFS showed only borderline significance (P = .053). Treatment related hematotoxicity in terms of grade 3/4 leukopenia was lowest among TS-3R/+6 haplotype carriers (P = .037). Grade 3/4 neutropenia was directly associated with the MTR-2756G/G genotype (P = .011), GSTP1-105Ile/Ile genotype (P = .02), and with the ERCC1-118T/8092C-haplotype (P = .042). In addition, significant associations between GSTP1-105Ile/Ile genotype and neurotoxicity and between the XPD-Asn312/751Gln haplotype and nephrotoxicity could be identified (P = .028 and P = .005, respectively). CONCLUSION: These findings underline the hypothesis that germ-line polymorphisms may play an important role in individualizing chemotherapy in AGC and deserve further prospective evaluation in AGC patients.

Melanocyte differentiation antigen RAB38/NY-MEL-1 induces frequent antibody responses exclusively in melanoma patients.

Expression pattern and immunogenicity are critical issues that define tumor antigens as diagnostic markers and potential targets for immunotherapy. The development of SEREX (serological analysis of recombinant expression libraries) has provided substantial progress in the identification of tumor antigens eliciting both cellular and humoral immune responses in cancer patients. By SEREX, we have previously identified RAB38/NY-MEL-1 as a melanocyte differentiation antigen that is highly expressed in normal melanocytes and melanoma tissues but not in other normal tissues or cancer types. In this study, we further demonstrate that RAB38/NY-MEL-1 is strongly immunogenic, leading to spontaneous antibody responses in a significant proportion of melanoma patients. The immune response occurs solely in malignant melanoma patients and was not detected in patients with other diseases, such as vitiligo, affecting melanocytes. Fine analysis of the spontaneous anti-RAB38/NY-MEL-1 antibody response reveals a polyclonal B cell recognition targeting various epitopes, although a dominant immunogenic region was preferentially recognized. Interestingly, our data indicate that this recognition is not rigid in the course of a patient's response, as the dominant epitope changes during the disease evolution. Implications for the understanding of spontaneous humoral immune responses are discussed.

Spontaneous CD8 T cell responses against the melanocyte differentiation antigen RAB38/NY-MEL-1 in melanoma patients.

The melanocyte differentiation Ag RAB38/NY-MEL-1 was identified by serological expression cloning (SEREX) and is expressed in the vast majority of melanoma lesions. The immunogenicity of RAB38/NY-MEL-1 has been corroborated previously by the frequent occurrence of specific Ab responses in melanoma patients. To elucidate potential CD8 T cell responses, we applied in vitro sensitization with overlapping peptides spanning the RAB38/NY-MEL-1 protein sequence and the reverse immunology approach. The identified peptide RAB38/NY-MEL-1(50-58) exhibited a marked response in ELISPOT assays after in vitro sensitization of CD8 T cells from HLA-A *0201(+) melanoma patients. In vitro digestion assays using purified proteasomes provided evidence of natural processing of RAB38/NY-MEL-1(50-58) peptide. Accordingly, monoclonal RAB38/NY-MEL-1(50-58)-specific T cell populations were capable of specifically recognizing HLA-A2(+) melanoma cell lines expressing RAB38/NY-MEL-1. Applying fluorescent HLA-A2/RAB38/NY-MEL-1(50-58) multimeric constructs, we were able to document a spontaneously developed memory/effector CD8 T cell response against this peptide in a melanoma patient. To elucidate the Ag-processing pathway, we demonstrate that RAB38/NY-MEL-1(50-58) is produced efficiently by the standard proteasome and the immunoproteasome. In addition to the identification of a RAB38/NY-MEL-1-derived immunogenic CD8 T cell epitope, this study is instrumental for both the onset and monitoring of future RAB38/NY-MEL-1-based vaccination trials.

Phase II trial of biweekly infusional fluorouracil, folinic acid, and oxaliplatin in patients with advanced gastric cancer.

PURPOSE: To evaluate the toxicity and activity of infusional fluorouracil (FU), folinic acid (FA), and oxaliplatin, administered every 2 weeks in patients with metastatic gastric cancer. PATIENTS AND METHODS: Forty-one previously untreated patients with measurable adenocarcinoma of the stomach were eligible for the study. Patients received FU 2.6 g/m(2) (24-hour continuous infusion), FA 500 mg/m(2) (2-hour intravenous infusion), and oxaliplatin 85 mg/m(2) (2-hour intravenous infusion) every 2 weeks for 6 weeks. Treatment was continued until progression of disease was observed. RESULTS: All patients were assessable for toxicity and 37 of 41 patients were assessable for response. Patient characteristics were: sex (male, 28; female,13), median age 60 years (range, 20 to 77 years), and median Eastern Cooperative Oncology Group performance status of 1. Response was evaluated every 6 weeks. Of 37 assessable patients, one complete and 15 partial remissions were observed (overall response rate, 43%). Stable disease was observed in 12 patients (32%) and progressive disease in nine patients (24%). The median overall survival was 9.6 months. WHO grade 3 or 4 hematologic toxicities included neutropenia in two patients (4.9%) and thrombocytopenia in one patient (2.4%). Other WHO grade 3 or 4 toxicities included diarrhea in three patients (7.3%) and vomiting in two patients (4.9%). There were no cases of grade 3 peripheral neuropathy and no treatment-related deaths. CONCLUSION: Biweekly fluorouracil, folinic acid, and oxaliplatin is active and well-tolerated in patients with advanced gastric cancer. Response rates, time to progression, and overall survival were comparable to those achieved with other combination chemotherapy regimens, including FOLFOX6, with significantly less toxicity.