Peripheral blood progenitor cells (PBPCs) are increasingly used for autografting after high-dose chemotherapy. One advantage of PBPCs over the use of autologous bone marrow would be a reduced risk of tumor-cell contamination. However, the actual level of tumor cells contaminating PBPC harvests is poorly investigated. It is currently not known whether mobilization of PBPCs might also result in mobilization of tumor cells. We evaluated 358 peripheral blood samples from 46 patients with stage IV or high-risk stage II/III breast cancer, small cell (SCLC) or non- small cell (NSCLC) lung cancer, as well as other advanced malignancies for the detection of epithelial tumor cells. Monoclonal antibodies against acidic and basic cytokeratin components and epithelial antigens (HEA) were used in an alkaline phosphatase-anti-alkaline phosphatase assay with a sensitivity of 1 tumor cell within 4 x 10(5) total cells. Before initiation of PBPC mobilization, circulating tumor cells were detected in 2/7 (29%) patients with stage IV breast cancer and in 2/10 (20%) patients with extensive-disease SCLC, respectively. In these patients, an even higher number of circulating tumor cells was detected after chemotherapy with VP16, ifosfamide, and cisplatin (VIP) followed by granulocyte colony-stimulating factor (G-CSF). This approach has previously been shown to be highly effective in mobilizing PBPCs. In the 42 patients without circulating tumor cells during steady state, tumor cells were mobilized in 9/42 (21%) patients after VIP+G-CSF induced recruitment of PBPCs. The overall incidence of tumor cells varied between 4 and 5,600 per 1.6 x 10(6) mononuclear cells analyzed. All stage IV breast cancer patients and 50% of SCLC patients were found to concomitantly mobilize tumor cells and PBPCs. Kinetic analyses showed two patterns of tumor cell recruitment depending on the presence or absence of bone marrow disease: (1) early after chemotherapy (between days 1 and 7) in patients without marrow infiltration, and (2) between days 9 and 16 in patients with marrow infiltration, ie, within the optimal time period for the collection of PBPCs. We show that there is a high proportion of patients with circulating tumor cells under steady-state conditions, and in addition a substantial risk of concomitant tumor cell recruitment upon mobilization of PBPCs, particularly in stage IV breast cancer patients with bone marrow infiltration. The biologic and clinical significance of this finding is unknown at present.

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To provide sufficient numbers of peripheral blood progenitor cells (PBPCs) for repetitive use after high-dose chemotherapy, we investigated the ability of hematopoietic growth factor combinations to expand the number of clonogenic PBPCs ex vivo. Chemotherapy plus granulocyte colony-stimulating factor (G-CSF) mobilized CD34+ cells from 18 patients with metastatic solid tumors or refractory lymphomas were cultured for up to 28 days in a liquid culture system. The effects of interleukin-1 beta (IL-1), IL-3, IL-6, granulocyte-macrophage-CSF (GM-CSF), G-CSF, macrophage-CSF (M-CSF), stem cell factor (SCF), erythropoietin (EPO), leukemia inhibitory factor (LIF), and interferon- gamma, as well as 36 combinations of these factors were tested. A combination of five hematopoietic growth factors, including SCF, EPO, IL-1, IL-3, and IL-6, was identified as the optimal combination of growth factors for both the expansion of total nucleated cells as well as the expansion of clonogenic progenitor cells. Proliferation peaked at days 12 to 14, with a median 190-fold increase (range, 46- to 930- fold) of total clonogenic progenitor cells. Expanded progenitor cells generated myeloid (colony-forming unit-granulocyte-macrophage), erythroid (burst-forming unit-erythroid), as well as multilineage (colony-forming unit-granulocyte, erythrocyte, monocyte, megakaryocyte) colony-forming units. The number of multilineage colonies increased 250- fold (range, 33- to 589-fold) as compared with pre-expansion values. Moreover, the absolute number of early hematopoietic progenitor cells (CD34+/HLA-DR-; CD34+/CD38-), as well as the number of 4-HC-resistant progenitors within expanded cells increased significantly. Interferon- gamma was shown to synergize with the 5-factor combination, whereas the addition of GM-CSF significantly decreased the number of total clonogenic progenitor cells. Large-scale expansion of PB CD34+ cells (starting cell number, 1.5 x 10(6) CD34+ cells) in autologous plasma supplemented with the same 5-factor combination resulted in an equivalent expansion of progenitor cells as compared with the microculture system. In summary, our data indicate that chemotherapy plus G-CSF-mobilized PBPCs from cancer patients can be effectively expanded ex vivo. Moreover, our data suggest the feasibility of large- scale expansion of PBPCs, starting from small numbers of PB CD34+ cells. The number of cells expanded ex vivo might be sufficient for repetitive use after high-dose chemotherapy and might be candidate cells for therapeutic gene transfer.

8020 Background: The SATURN (BO18192) study investigated whether erlotinib maintenance therapy improved PFS in patients (pts) with advanced NSCLC who had obtained clinical benefit from 1st-line chemotherapy. This study included a prospective analysis of the prognostic/predictive value of several molecular markers. Methods: 889 pts with advanced NSCLC whose disease had not progressed following 4 cycles of 1st-line platinum-doublet chemotherapy were randomized to erlotinib 150 mg/day or placebo. Mandatory tumor specimens were collected at baseline and tested for EGFR protein expression using immunohistochemistry (IHC), EGFR gene copy number using fluorescent in-situ hybridization (FISH), and EGFR and KRAS somatic mutations using DNA sequencing. Pts were stratified according to EGFR IHC status (any membranous staining in ≥10% tumor cells used as cut-off); the co-primary endpoint was PFS in EGFR IHC+ pts. Baseline whole blood samples were obtained for genotyping of EGFR (intron 1 CA-repeat polymorphisms). Results: In the overall population, erlotinib significantly prolonged PFS vs placebo (HR 0.71, p<.0001; primary endpoint). The co-primary endpoint was also met, with erlotinib significantly improving PFS in the EGFR IHC+ group (HR 0.69, p<.0001). Many tumor samples were assessable for molecular marker status (see table). Biomarker data suggest that patients derived a PFS benefit with erlotinib irrespective of EGFR FISH or EGFR intron 1 CA-repeat status. The magnitude of benefit with erlotinib was similar in both KRAS-mutant and KRAS wild-type pts. Conclusions: This is the largest biomarker analysis performed for erlotinib in a randomized, placebo-controlled setting, and answers key scientific questions regarding the prognostic and predictive value of potential biomarkers of efficacy. Full data will be presented. [Table: see text] [Table: see text]

Background: Ether lipids could provide new prospects in cancer therapy after successful preclinical investigations. Edelfosine has been the most thoroughly investigated substance in the ether lipid group. So far, no standard therapy has been set up for advanced non-small-cell bronchogenic carcinoma. Therefore, in a phase II study 116 patients with advanced inoperable non-small-cell bronchogenic carcinoma were treated with the alkyl-lysophospholipid edelfosine (EF). Material and Methods: The phenotype modifier EF was initially applied in a daily oral dosage of 300 mg (dissolved in milk) over a period of 4 weeks, then increased to a daily dosage of 900 mg if tolerated well, and continued with the highest tolerable dosage. Therapy was continued until either tumor progression or negative side effects were documented. 35 patients could not be treated for the intended therapy period of at least 8 weeks due to early tumor progression (18 patients), unacceptable gastrointestinal side effects (14 patients), lack of compliance (1 patient), refusal of therapy (1 patient) and change of therapy (1 patient). Results: 81 patients could be evaluated for remission status; of these, 2 showed partial remission, 68 showed ‘no change’, and 11 had unaltered progression of the tumor. Median survival time for these 81 patients was 244 days, for all 116 patients it was 199 days. Retrospectively, in these 81 patients the spontaneous tumor development during the 2 months before EF therapy could be analyzed. Tumor progression during this period could be documented in 1 patient with partial remission, in 46 patients with diagnosis ‘no change’, and in 11 patients with unaltered tumor progression. The survival times of these three groups of patients did not differ significantly. All 116 patients were evaluable for toxicity. Manifestations of gastrointestinal problems were anorexia, nausea, vomiting, diarrhea, obstipation (mostly WHO grades I+Π), but treatment was not required. Toxic effects on organs or late toxicity could not be documented.Conclusions: The high proportion of patients with stationary tumor status was remarkable. Objective tumor remission was extremely rare. On the other hand, the rate of progression was low. This might be explained by the fact that EF is rather a phenotype modifier than a typical cytostatic drug.