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G G Steger

Publications and source records attributed to G G Steger.

At least 19 recordsLinked to original sources
PubMed2003

Her-2/neu-triggered intracellular tyrosine kinase activation: in vivo relevance of ligand-independent activation mechanisms and impact upon the efficacy of trastuzumab-based treatment.

Proteolytic cleavage of the Her-2/neu extracellular domain (ECD) has been shown to initiate receptor phosphorylation representing Her-2/neu activation in vitro. The present investigation was performed to evaluate the clinical relevance of ECD cleavage for Her-2/neu activation and the consequences of active intracellular Her-2/neu signalling reflected by tyrosine kinase phosphorylation in patients treated with the anti-Her-2/neu antibody trastuzumab. Sera from 62 patients receiving trastuzumab-based treatment for Her-2/neu overexpressing metastatic breast cancer were assessed for pretreatment ECD levels using an enzyme-linked immunosorbent assay. In parallel, Her-2/neu activation status of tumour specimens was assessed by immunohistochemistry using a Her-2/neu phosphorylation state specific antibody (PN2A) and correlated with the patients' ECD levels and clinical course of disease. Serum ECD levels were significantly higher in 15 (24%) patients with tumours exhibiting activated Her-2/neu as compared to those without detectable Her-2/neu phosphorylation (median 148.2 vs 28.5 ng ml(-1), P=0.010). Whereas response rate only showed a trend to be higher in patients with Her-2/neu-phosphorylated breast cancer (47 vs 34%, P=0.197), both uni- and multivariate analyses revealed that the median progression-free survival under trastuzumab-based treatment was significantly longer in patients with Her-2/neu-phosphorylated breast cancer-11.7 (95% CI 5.2-18.3) months-when compared to the progression-free survival of 4.5 (95% CI 3.4-5.6) months observed in patients with tumours lacking phosphorylated Her-2/neu (P=0.001). Proteolytic cleavage of the ECD represents a biologically relevant ligand-independent mechanism of Her-2/neu activation in vivo. The influence of Her-2/neu activation status upon the outcome of trastuzumab-based therapies merits further investigation in larger prospective trials.

Adult↗
PubMed2003

Penetration of capecitabine and its metabolites into malignant and healthy tissues of patients with advanced breast cancer.

Capecitabine is an oral prodrug of 5-fluorouracil (FU). Since FU concentrations achieved in malignant lesions are an important determinant of efficacy, we investigated the intratumoral transcapillary transfer of capecitabine and its metabolites in vivo. A total of 10 patients with skin metastases from breast cancer received a daily dose of 2500 mg m(-2) capecitabine administered orally in two divided doses for 2 weeks. Microdialysis probes were inserted into a cutaneous metastasis and subcutaneous connective tissue to evaluate the interstitial tissue pharmacokinetics of capecitabine and its metabolites 5'-deoxy-5-fluorocytidine (DFCR), 5'-deoxy-5-fluorouridine (DFUR), and FU by capillary electrophoresis. As intended with the prodrug design of capecitabine, FU was present in low concentrations in tumour interstitium (median c(max): 0.26 microg ml(-1)) when compared with capecitabine, DFCR, and DFUR (median c(max): 2.66, 4.22, and 2.13 microg ml(-1), respectively). Capecitabine and its metabolites easily penetrated malignant and healthy tissue and equilibrated within 45 min between plasma and tissue interstitium. Considering tissue exposure at the extracellular level, no significant differences between healthy and malignant tissues were observed. Our data show that absorption and metabolism determined the tissue pharmacokinetics of capecitabine. There was no evidence of drug tolerance, which may be attributed to impaired transcapillary transfer into tissue, even after repeated administration as shown for three patients.

Adult↗
PubMed2002

On-line solid-phase extraction and determination of paclitaxel in human plasma.

The application of coupled-column liquid chromatographic analysis to pharmacokinetic studies eliminates the need for sample clean-up from plasma. Considering lipophilic antineoplastic agents, we tested this approach to analyze paclitaxel under unfavourable circumstances (i.e., weekly low-dose regimen, plasma protein binding >90%, UV detection at 229 nm). The excellent quality control data (recovery: 95.6-100.7%, inter-assay relative standard deviation on 5 days: 1.3-3.2%, accuracy: 0.9-2.7%) and the detection limit of 19 nM indicates the usefulness of this method for the analysis of paclitaxel in plasma using on-line solid-phase extraction.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Docetaxel monotherapy in heavily pretreated metastatic breast cancer: a multicenter, community-based feasibility trial.

PURPOSE: To evaluate the efficacy and safety of docetaxel in heavily pretreated and anthracycline-resistant patients with metastatic breast cancer in an outpatient setting. PATIENTS AND METHODS: Between February 1996 and June 1998, 98 consecutive patients who had progressed during or relapsed following prior anthracycline-containing chemotherapy were enrolled into the trial. Docetaxel was administered at a dose of 100 mg/m2 by intravenous infusion every 3 weeks. The administration of colony-stimulating factors was at the discretion of the attending physician. Premedication with dexamethasone was mandatory for all patients. RESULTS: Of the 98 patients, 93 were evaluable for toxicity and response. Patients had received two palliative regimens (median, range 1-5) prior to docetaxel treatment. The most frequent toxicity observed was leukopenia grade III and IV (WHO grading system) which occurred in 47% of patients (grade IV only in 14%). Except for alopecia grade III (64% of patients), nonhematologic side effects grade III-IV were rare (1-7% of patients) and included nausea, stomatitis, diarrhea, peripheral neuropathy, fluid retention and pulmonary toxicities. There were no treatment-related deaths. Objective responses occurred in 40% of patients (CR 6%, PR 34%), and stable disease in 38% of patients. The median duration of response was 5.3 months (range 0.7-18.1 months) while the median survival was 15 months (range 2 36 months). CONCLUSION: Docetaxel is a highly active agent in patients with anthracycline-resistant metastatic breast cancer, even in heavily pretreated patients, with moderate toxicity.

Adolescent↗
PubMed2001

Decrease of duration and symptoms in chemotherapy-induced oral mucositis by topical GM-CSF: results of a prospective randomised trial.

We have conducted a prospective controlled randomised clinical study testing for the efficacy of topical GM-CSF (molgramostim), as compared to the combined topical use of an antiseptic agent (povidone-iodine) and amphotericin B (AA) in patients with chemotherapy-induced mucositis World Health Organization (WHO) grades I-III. 31 patients (17 females, 14 males) developing oral mucositis following the administration of 5-fluorouracil (5-FU)-based chemotherapy were entered into the present trial. 15 patients were randomised to receive GM-CSF mouthwashes, whereas 16 patients were randomised into the control arm to receive AA. Reported history (P=0.6109) and grading of oral mucositis (2.1+/-0.7, respectively; P=0.9867) were balanced and equally distributed between the two groups. The mean size of lesions of oral mucositis was 1.5+/-0.6 cm (range: 0.7-2.5 cm) in the GM-CSF group and 1.2+/-0.5 cm (range: 0.5-2.5 cm) in the AA group (P=0.08), respectively. The mean number of oral mucositis lesions was 1.9+/-1.1 (range: 1-4) in the GM-CSF group and 2.1+/-1.2 (range: 1-4) in the AA group (P=0.63), respectively. None of the patients had previously received colony stimulating factors either topically or systemically. Treatment for oral mucositis was initiated on day 2.7+/-1.2 (range: day 1-8) after onset of symptoms in the GM-CSF group and on day 1.8+/-1.4 (range: day 1-3; P=0.11) in the AA group. The topical application of GM-CSF resulted in a significantly shorter duration and quicker resolution of oral mucositis, as compared to AA including both, pretreatment plus treatment periods (5.3+/-2.5 versus 8.1+/-1.5 days; P=0.0008) as well as the necessary duration of treatment needed until complete remission of lesions (2.8+/-0.7 versus 6.3+/-1.1 days; P<0.0001). A systemic effect of topical GM-CSF upon the number of peripheral blood leukocytes or granulocytes was excluded. We conclude that the topical application of GM-CSF by mouthwash significantly abbreviated the duration and relieved patients from symptoms of chemotherapy-induced mucositis and was superior to the topical application of AA.

Adult↗
PubMed2001

Reverse transcriptase template switching during reverse transcriptase-polymerase chain reaction: artificial generation of deletions in ribonucleotide reductase mRNA.

Using reverse transcriptase-polymerase chain reaction (RT-PCR), we have recently described a bona fide deletion within the coding sequence of the large subunit of ribonucleotide reductase (R1) mRNA in colon cancer. Consecutive studies have raised questions about the nature of this phenomenon, because the corresponding genomic alteration at the DNA level or an aberrant protein could not be detected. Thus we considered an in vitro artifact during RT-PCR as a possible explanation for this observation. In contrast to reverse transcriptase, Taq DNA polymerase or C. therm DNA polymerase did not generate the aberrant product, suggesting the demand for the template switching activity intrinsic to retroviral reverse transcriptases. In fact, virtually the same deletion was observed in RT-PCR experiments when in vitro transcribed R1 mRNA was used. Considering structural prerequisites for template switching within R1 mRNA, we show that two direct repeats adjacent to a strong stem-loop secondary structure flank the deleted region of 1851 base pairs. Because several mRNAs encoding proteins of clinical and diagnostic importance fulfill these criteria, template switching enhances the potential risk of observing artifacts when interpreting results from RT-PCR studies. As shown in the present example, this may involve the artificial generation and the misinterpretation of PCR fragments amplified from targets relevant to tumor biology or cancer pharmacology. As a possible solution, one-step PCR with C. therm polymerase should be considered. This polymerase eliminates the artificial generation of aberrant mRNA signals observed during cDNA synthesis.

Adenocarcinoma↗
PubMed2001

Unexpected severe myelotoxicity of gemcitabine in pretreated breast cancer patients.

Gemcitabine is a chemotherapeutic agent with proven antitumor effects in pancreatic and non-small cell lung cancer; however, studies establishing the definite significance in other solid tumors are still in progress. We herein present three female patients with advanced breast cancer who received gemcitabine as salvage chemotherapy. Gemcitabine at a dose of 1250 mg/m2 was scheduled for days 1, 8 and 15 with a subsequent rest for 1 week. However, within 1 week after the very first administration of gemcitabine myelotoxicity WHO grade IV occurred in all patients, leading to discontinuation of therapy. In two patients this gemcitabine-induced hematotoxicity could be overcome by means of vigorous supportive care, but one patient died after cerebral bleeding due to severe thrombocytopenia. We conclude that gemcitabine in heavily pretreated breast cancer patients should only be used with extreme caution with special focus on platelet counts until solid data from clinical studies for doses and schedules are available.

Adult↗
PubMed2000

Glutathione in the prevention of cisplatin induced toxicities. A prospectively randomized pilot trial in patients with head and neck cancer and non small cell lung cancer.

PURPOSE: Glutathione has been shown to be an effective chemoprotector against cisplatin-induced side effects in patients with ovarian cancer. In view of this fact, we performed a randomized clinical pilot-trial in the management of other solid tumors in order to compare application of Glutathione to intensive hydration in patients undergoing chemotherapy with a regimen including cisplatin. PATIENTS AND METHODS: Twenty patients suffering from advanced non small cell lung cancer (n = 6) or head- and neck cancer (n = 14) were enrolled in the study. All patients received 80 mg/m2 cisplatin along with etoposide or 5-fluorouracil every 4 weeks. Patients randomized to application of Glutathione (n = 11) received 5 g of Glutathione immediately before application of cisplatin followed by 2000 ml of normal saline. Patients in the control group (n = 9) received 2000 ml electrolyte infusion before and 2000 ml of normal saline with forced diuresis after cisplatin. RESULTS: The intensity of hematologic toxicity was significantly less pronounced in patients treated with Glutathione than in the control group (hemoglobin: 10.7 vs 9.5 mg% respectively, p = 0.039; white blood cell count 3.3 vs 2.2 x 103/microliter respectively, p = 0.004; platelets 167 vs 95 x 103/microliter respectively, p = 0.02), whereas in terms of non-hematologic toxicity no difference was observed. Objective remission occurred in 6 out of 11 evaluable patients from the group receiving Glutathione (55%; complete remission: 9%; partial remission: 46%), and in 4 out of 8 evaluable patients from the control group (partial remission: 50%). However, there was no statistical difference in terms of response and overall survival (13.5 months vs. 10.5 months) between the two groups. CONCLUSIONS: Application of Cisplatin and Glutathione seems to be safe and feasible and the antitumoral efficacy of cisplatin is apparently not impaired by the concomitant use of Glutathione in patients with solid tumors.

Adult↗
PubMed2000

Sequential administration of interferon gamma and interleukin-2 in metastatic renal cell carcinoma: results of a phase II trial. Austrian Renal Cell Carcinoma Study Group.

BACKGROUND: Because of the known efficacy of several cytokines in the treatment of advanced renal cell cancer (RCC), we have conducted a phase II trial of the efficacy and toxicity of subcutaneous interferon gamma (IFNgamma) and interleukin-2 (IL-2). METHODS: 63 patients with progressive metastatic RCC were treated with 100 microg recombinant IFNgamma1b administered three times weekly during weeks 1 and 2 and with 4.5 MU recombinant IL-2 administered on 4 consecutive days during weeks 3 and 4, every 6 weeks. RESULTS: 11% of patients had an objective response (CR: 3%, PR: 8%), 33% had SD. Toxicity was generally mild. The median duration of remissions (CR + PR) was 9.6 months; the median duration of SD 8 months. A significant survival benefit was evident at a median observation time of 51 months for patients (44%) responding to therapy (P < 0.0001). CONCLUSIONS: we conclude that sequential treatment with IFNgamma and IL-2 may prolong survival in patients with metastatic RCC responding to therapy.

Adult↗
PubMed2000

Relationship between in vivo drug exposure of the tumor interstitium and inhibition of tumor cell growth in vitro: a study in breast cancer patients.

A novel approach is described to simulate effect site pharmacodynamics of anticancer drugs. This approach is based on (i) the in vivo measurement of unbound, interstitial drug pharmacokinetics (PK) in solid tumor lesions in patients and (ii) a subsequent pharmacodynamic (PD) simulation of the time versus drug concentration profile in an in vitro setting. For this purpose, breast cancer cells (MCF-7) were exposed in vitro to the time versus interstitial tumor concentration profiles of 5-fluorouracil (5-FU) and methotrexate (MTX) from primary breast cancer lesions in patients. This led to a maximal reduction in the viable cell count of 69% on day 4, and of 71% on day 7 for 5-FU and MTX, respectively. This effect was dependent on the initial cell count and was characterized by a high interindividual variability. For 5-FU there was a significant correlation between the maximum antitumor effect and the intratumoral AUC (r = -0.82, p = 0.0005), whereas no correlation could be shown for MTX (r = 0.05, p = 0.88). We conclude, that the in-vivo-PK / in-vitro-PD model presented in this study may provide a rational approach for describing and predicting pharmacodynamics of cytotoxic drugs at the target site. Data derived from this approach support the concept that tumor penetration of 5-FU may be a response-limiting event, while the response to MTX may be determined by events beyond interstitial fluid kinetics.

Antimetabolites, Antineoplastic↗
PubMed2000

Genetic analysis of multiple synchronous lesions of the colon adenoma-carcinoma sequence.

The colorectal adenoma-carcinoma sequence represents a well-known paradigm for the sequential development of cancer driven by the accumulation of genomic defects. Although the colorectal adenoma-carcinoma sequence is well investigated, studies about tumours of different dignity co-existent in the same patient are seldom. In order to address the distribution of genetic alterations in different lesions of the same patient, we coincidently investigated carcinomas, adenomas and aberrant crypt foci in patients with sporadic colon cancer. By utilizing polymerase chain reaction, single-strand conformation polymorphism, heteroduplex-analysis, restriction fragment length polymorphism, protein truncation test and sequencing techniques we looked for mutations and microsatellite instability of APC, H-ras, K-ras, p53, DCC and the DNA repair genes hMLH1/hMSH2. In accordance with the suggested adenoma-carcinoma sequence of the colon, four patients reflected the progressive accumulation of genetic defects in synchronously appearing tumours during carcinogenesis. However, two patients with non-hereditary malignomas presented different genetic instabilities in different but synchronously appearing tumours suggesting non-clonal growth under almost identical conditions of the environment. Thus, sporadically manifesting multiple lesions of the colon were not necessarily driven by similar genetic mechanisms. Premalignant lesions may transform into malignant tumours starting from different types of genetic instability, which indicates independent and simultaneous tumorigenesis within the same organ.

Adenocarcinoma↗
PubMed2000

Tumor antigen pulsed dendritic cells enhance the cytolytic activity of tumor infiltrating lymphocytes in human hepatocellular cancer.

OBJECTIVE: Tumor infiltrating lymphocytes (TILs) stimulated with interleukin-2 (IL-2) ex vivo have been successfully used therapeutically in some cancer patients, but their potency in eliciting an effective anti-tumor response is variable. We have tried to augment killing activity of tumor infiltrating lymphocytes derived from hepato-cellular carcinoma (HCC) using autologous monocytes derived dendritic cells. METHODS: Tumor infiltrating lymphocytes (TILs) from 6 patient with hepatocellular carcinoma were isolated and the phenotype were further characterized. From the same patients, autologous dendritic cells were generated from CD14+ monocytes that were cultured for 6 days in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4). Those professional antigen presenting cells were pulsed with whole autologous hepatoma tumor lysates (pDC). TILs were cocultured with pDC or unpulsed DC. To assess the cytotoxic potency of TILs, the ability to lyse the tumor cell targets K652, Daudi and an allogeneic HCC celline was determined in a standard cytotoxic assay. RESULTS: Tumor cells targets in vitro are poorly lysed by tumor infiltrating lymphocytes indicating T-cell hyporesponsiveness. In contrast, the killing activity of HCC derived TILs against Daudi (9.15% +/- 7.5) and allogeneic HCC tumor target (18.2% +/- 9.2) could be significantly augmented when stimulated with pDC (Daudi: 38% +/- 6.8 and allogeneic HCC: 55% +/- 10). The killing activity of TILs against K562 was unaffected by pDC. CONCLUSION: The low cytotoxic activity profile of HCC derived TILs in vitro can be increased by tumor lysate pulsed dendritic cells and may therefore be more effective in vivo when used for adoptive immunotherapy.

Antigens, Neoplasm↗
PubMed2000

Monotherapy with docetaxel in second- or third-line treatment of anthracycline-resistant metastatic breast cancer.

Nineteen breast cancer patients pretreated with one or two anthracycline-containing regimens for visceral metastases received i.v. docetaxel 100 mg/m2 on day 1, q 21d. Docetaxel was administered as second-line therapy in 11 patients, whereas eight patients received docetaxel in a third-line setting. In the second-line setting, complete response (CR) was achieved in two (18%), partial response (PR) in four (36%) and stable disease (SD) in three (27%) patients resulting in a response rate (RR) of 54%. In the third-line setting three (38%) patients experienced PR (RR 38%) and two (25%) SD. In the second-line setting, median time to progression was 6.5+/-3.9 months (range 2.1-15.8) versus 4.7+/-5.5 months (range 0.6-15.9) in the third-line setting. Median overall survival was 9.6+/-8.0 months (range 2.7-25.8) versus 11.2-6.1 months (range 4.8-18.7). Overall, no patient experienced treatment-limiting toxicities. We conclude that docetaxel induced responses in 48% of anthracycline-resistant patients enrolled into the present study. The safety profile of docetaxel was manageable and tolerable. Docetaxel represented efficacious treatment in patients with metastatic breast cancer progressing despite previous anthracycline-containing chemotherapy.

Adult↗
PubMed2000

Vinorelbine and interferon-alpha2c as second-line therapy in metastatic renal cell carcinoma.

Second-line treatment of patients with metastatic renal cell carcinoma (MRCC) progressing under therapy with biological response modifiers (BRM) is an unresolved issue. Thirty-seven patients with MRCC progressing under treatment with BRM received vinorelbine i.v. at a dose of 30 mg/m2 q 22 days and 4,800,000 IU interferon (IFN)-alpha2c s.c. thrice weekly. Partial remission (PR) occurred in 8% of patients, stable disease (SD) (median duration 8, range 3-35+ months) was observed in 46% of patients. Median overall survival was 15 (range 1-49) months. No major toxicities occurred. Patients with MRCC who failed first-line treatment with BRM had a high chance to enter PR or SD under combined, low-toxic therapy with vinorelbine and IFN-alpha2c.

Adult↗
PubMed2000

Phase II study of gemcitabine in combination with cisplatin in patients with locally advanced and/or metastatic pancreatic cancer.

The present phase II trial was performed to assess the efficacy and toxicity of polychemotherapy with gemcitabine and cisplatin in patients with locally advanced or metastatic carcinoma of the pancreas. Sixteen patients received six courses of an i.v. cytotoxic regimen consisting of gemcitabine (1000 mg/m2, days 1, 8 and 15) and cisplatin (35 mg/m2, days 1, 8 and 15) administered in 28-day intervals. Complete remission (CR) occurred in one patient (6%), partial remission (PR) in four patients (25%) and stable disease in seven patients (44%), whereas four patients (25%) developed progressive disease resulting in an overall response rate of 31%. Mean duration of responses (CR+PR) was 3.6 (range 0.7-8.5) months and mean time to progression was 7.4 (range 3.8-12.6) months. After a mean observation period of 11.5 months the overall survival was 9.6 months with 12 patients (75%) still being alive, which compares favorably with historical data of the administration of gemcitabine alone. The performance status improved in three (19%) and stabilized in eight (50%) out of 16 patients for 4 weeks or longer. Treatment-associated toxicity included alopecia of WHO grade III in all cases, leukopenia of WHO grades I and II in 10 patients (63%), grade III in five patients (31%), and thrombocytopenia grades I and II in four patients (25%), and grades III and IV in 10 patients (63%). We conclude that the administered dosage and schedule of gemcitabine and cisplatin in patients with locally advanced or metastatic cancer of the pancreas constitutes an active cytotoxic regimen associated with moderate toxicity.

Adenocarcinoma↗
PubMed2000

Benefit of interferon-alpha2b in a patient with unresectable hepatoma and chronic infection with hepatitis C virus.

Only in a small proportion of patients is advanced hepatocellular carcinoma (HCC) resectable, so the need for effective non-surgical treatments is obvious. We present details of a 72-year-old woman with inoperable HCC and chronic infection with hepatitis C virus, proved by the presence of antibodies directed against hepatitis C virus and positive polymerase chain reaction. The patient was treated with subcutaneous recombinant human interferon-alpha-2b. Within a few weeks, a partial tumour remission, paralleled by a decrease in serum levels of tumour markers and liver enzymes, was observed. In addition, polymerase chain reaction became negative. This observation facilitates the hypothesis that the anti-viral effects of interferon might have been jointly responsible for the anti-tumour activity observed. Interferon-alpha might serve as a treatment option in patients with unresectable hepatoma and chronic active viral hepatitis, but prospective studies are warranted.

Aged↗
PubMed2000

Relation of pro- and anti-inflammatory cytokines and the production of nitric oxide in patients receiving high-dose immunotherapy with interleukin-2.

Immunotherapy with intravenous recombinant human interleukin-2 (rh IL-2) may be accompanied by hypotension and the emergence of capillary leak syndrome. Nitric oxide (NO) is supposed to be responsible for both side effects. The aim of the current investigation was to elucidate the relationship between pro- and anti-inflammatory cytokines and the production of NO in eight tumor patients receiving intravenous rh IL-2 continuously over a time period of 120 hours. Markers of systemic inflammation, as well as nitrate plasma levels, were consecutively determined. Significant changes in the levels of pro-inflammatory cytokines IL-6 and IL-8 were observed (p < 0.05). In contrast to the anti-inflammatory cytokine IL-10, which did not increase significantly, the serum concentrations of the soluble tumor necrosis factor receptors (sTNFr) I and II rose continuously and significantly during the observation period (p < 0.05). In parallel, a significant rise in nitrate plasma levels was observed (p < 0.05). Moreover, there were highly significant correlations between nitrate and IL-6 serum levels (p < 0.05), nitrate and sTNFr-I (p < 0.05), nitrate and sTNFr-II (p < 0.05), and between IL-6 and IL-10 (p < 0.05), respectively. We conclude that immunotherapy with IL-2 promotes a pro-inflammatory state, parallelled by an increased production of nitric oxide. Although anti-inflammatory responses accompany this process, they are not able to diminish the production of nitric oxide.

Adult↗