Search PubMed⌕ Search

Biomedical subjects

A Ganser

Publications and source records attributed to A Ganser.

At least 37 records · Page 2Linked to original sources
PubMed2004

Treatment intensity significantly influencing fibrosis in bone marrow independently of the cytogenetic response: meta-analysis of the long-term results from two prospective controlled trials on chronic myeloid leukemia.

Bone marrow fibrosis (MF) has been shown to indicate therapy failure in Ph(+) chronic myeloid leukemia (CML). However, the results on the development of MF during interferon-alpha therapy of CML are controversial. The significance of the interferon dose has not been considered as yet. In total, 627 bone marrow biopsies taken prospectively from 200 patients with CML recruited in two studies using different doses of interferon-alpha +/- low-dose cytosine arabinoside were examined for MF before and during therapy. The results showed that the risk of MF depended significantly on the interferon-alpha dose applied (P<0.000005). MF progressed during low-dose therapy (3 x 5 x 10(6) IU/week), but was prevented from progression when applying high dose (5 x 10(6) IU/m(2)/per day). MF disappeared when high-dose interferon-alpha was combined with low-dose cytosine arabinoside (P<0.000005). The risk of death markedly increased when MF occurred or progressed (P<0.0009), independent of all other prognostic factors evaluated including the cytogenetic response. In conclusion, the effectiveness of interferon-alpha on MF depends on the treatment intensity. MF reverses when combining high-dose interferon-alpha with low-dose cytosine arabinoside, but progresses when applying low-dose interferon-alpha. MF appears to be a significant early indicator of ineffective therapy in CML.

Adult↗
PubMed2004

Analysis of factors contributing to higher erythropoietin levels in patients with chronic liver disease.

BACKGROUND: Dysregulated erythropoietin (EPO) plasma levels may play a role in the pathophysiology of chronic liver disease (CLD) because chronic anaemia is frequently observed in patients with liver cirrhosis. We aimed to identify the factors contributing to EPO regulation in patients with CLD. METHODS: Plasma EPO concentrations were correlated with clinical and laboratory parameters in 111 CLD patients and 220 healthy controls. RESULTS: Anaemia, though generally mild, was common in CLD patients, and thrombocytopenia and previous bleeding episodes were observed in two-thirds of the patients. Plasma EPO levels were significantly elevated in CLD patients (P < 0.001). EPO increased according to Child's stages of cirrhosis, independently of the aetiology of CLD. EPO correlated with haemoglobin (r= -0.498, P < 0.001). Additionally, EPO independently correlated with markers of liver dysfunction, e.g. prothrombin time, albumin concentration or cholinesterase activity, and platelet count. EPO was also significantly elevated in patients with a current bleeding tendency and with prior gastrointestinal haemorrhages. EPO levels were increased in patients with impaired pulmonary function, e.g. decreased diffusion capacity, vital capacity or hyperventilation. Interestingly, plasma interleukin-6 (IL-6) concentrations positively correlated with EPO (r=0.277, P = 0.003), suggesting a possible mechanism of EPO upregulation in patients with CLD through IL-6 dependent pathways, e.g. binding of STAT transcription factors in the putative EPO promoter region. CONCLUSIONS: EPO is upregulated in patients with chronic liver diseases in response to anaemia, bleeding complications, impaired pulmonary function, thrombocytopenia and liver dysfunction. IL-6 dependent pathways could be involved in mediating elevated EPO levels in CLD patients.

Adolescent↗
PubMed2004

Phase I and pharmacokinetic study of TZT-1027, a novel synthetic dolastatin 10 derivative, administered as a 1-hour intravenous infusion every 3 weeks in patients with advanced refractory cancer.

BACKGROUND: TZT-1027 is a synthetic dolastatin 10 analog with antineoplastic properties in various cell lines and tumor xenografts. The purpose of this phase I study was to evaluate the safety and toxicity, maximum tolerated dose, pharmacokinetics and pharmacodynamics, clinical and metabolic antitumor activity of TZT-1027 when given as a 1-h intravenous infusion every 3 weeks in patients with refractory solid tumors. PATIENTS AND METHODS: Patients had a histologically verified refractory tumor with measurable disease, were > or = 18 years old, had an Eastern Cooperative Oncology Group performance status <2 and adequate bone marrow, liver, renal and cardiac function. Dose-limiting toxicity was defined as platelets <25 x 10(9)/l, neutrophils <0.5 x 10(9)/l for >5 days, febrile neutropenia > or = 38.5 degrees C with grade 4 (National Cancer Institute-common toxicity criteria) neutropenia, or grade 3/4 non-hematological toxicity excluding nausea and vomiting. The last dose was the dose where > or = 2 out of six patients experienced dose-limiting toxicity in cycle one. The maximum tolerated dose was one dose level below with less than two of six patients with dose-limiting events. RESULTS: Twenty-one non-selected, fully evaluable patients were enrolled. The majority were male (19) and the median age was 55 years (range 39-67). Dose levels of TZT-1027 ranged from 1.35 to 3.0 mg/m(2). The median number of cycles was two (range 1-4). Dose-limiting toxicities were observed in three patients at the 3.0 mg/m(2) dose level, including neutropenia, fatigue and a short lasting, reversible peripheral neurotoxic syndrome. The most common toxicities per patient were fatigue, anorexia, alopecia, nausea, constipation, leukopenia and neutropenia. Based on RECIST criteria, the best response was stable disease in seven patients. The pharmacokinetic evaluation revealed a T(1/2) of approximately 7 h and linear kinetics. CONCLUSIONS: The recommended dose of TZT-1027 for the 3-weekly administration is 2.7 mg/m(2). Neutropenia, fatigue and a reversible peripheral neurotoxic syndrome are dose-limiting with this schedule. TZT-1027 may be associated with neurological side-effects in patients previously exposed to neurotoxic compounds such as oxaliplatin.

Adult↗
PubMed2004

Rituximab consolidation after high-dose chemotherapy and autologous blood stem cell transplantation in follicular and mantle cell lymphoma: a prospective, multicenter phase II study.

BACKGROUND: Patients with follicular (FL) or mantle cell lymphoma (MCL) are incurable with conventional therapy. We investigated the safety and efficacy of rituximab consolidation after autologous stem cell transplantation (ASCT) in order to prevent relapse by clearance of minimal residual disease (MRD). METHODS: Rituximab was given approximately 8 weeks after CD34+ cell enriched ASCT at 375 mg/m2, weekly for 4 weeks. Monitoring of MRD was performed by repetitive PCR analyses. RESULTS: Thirty-one patients were included; one died early after ASCT before rituximab administration. Thirty patients (20 FL, 10 MCL) were evaluable after rituximab consolidation, and 27 of these were assessable for MRD detection. Rituximab consolidation post-ASCT was safe, the most common toxicity being infection. At a median follow-up of 42 months (range 13-96) after ASCT, 25 patients were censored with an actuarial event-free survival (EFS) of 81% at 4 and 5 years. Four patients (two FL, two MCL) relapsed, and one additional MCL patient died unexpectedly in complete remission. PCR-negativity was observed in 22% of the patients before ASCT, 53% post-ASCT (P=0.0547), 72% after rituximab (P=0.0018) and 100% at 6 months post-transplant (P < 0.001). CONCLUSIONS: One single course of rituximab consolidation given after ASCT is safe, may help to eliminate MRD and may translate into improved EFS in both FL and MCL patients.

Adult↗
PubMed2003

Presentation assessment of minor histocompatibility antigens by predictive proteasomal cleavage analysis.

Minor histocompatibility peptides (mHps) derived from polymorphic segments of endogenous proteins are thought to be targets for graft-versus-host and graft-versus-leukemia reactions after HLA-identical stem cell transplantation. A great majority of antigenic peptides is generated by fragmentation of proteins in the course of proteasomal processing. An algorithm was recently developed to predict cleavage sites during proteasomal processing. We tested the accuracy of the algorithm to predict mHps using 18 amino acid (AA) sequences of minor histocompatibility antigens (mHags) encoded by autosomal genes representing single nucleotide polymorphisms or by Y-chromosomal genes. The algorithm correctly predicted the C-termini of 11 of 13 experimentally confirmed mHps: 1) Correct prediction of C- and N-termini, e.g., for HA-1(H); 2) Correct prediction of C- and N-termini while anticipating intra-epitope cleavage sites, e.g., for SMCY-A*0201; 3) Correct prediction of C-termini and N-terminal extensions, e.g., for HA-8(R/V); and 4) Correct prediction of C-termini and N-terminal extensions while anticipating intra-epitope cleavage sites, e.g., for UTY-B8. Analysis of experimentally unconfirmed allelic counterparts of four autosomal mHags showed that AA substitutions either led to the insertion of an epitope-destroying cleavage site (e.g., in HA-1(R)) or abolished the correct C-terminus (e.g., in HA-2(M)). The proteasomal processing algorithm provides reliable data on the generation of mHps and forecasts their presence or absence. Combined with MHC class I ligand prediction, it can be a useful tool for the prediction of generation and presentation of new CTL epitopes derived from minor histocompatibility antigens.

Algorithms↗
PubMed2003

Prior and concurrent administration of recombinant human megakaryocyte growth and development factor in patients receiving consolidation chemotherapy for de novo acute myeloid leukemia--a randomized, placebo-controlled, double-blind safety and efficacy study.

Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) administered after acute myeloid leukemia (AML) chemotherapy (CT) failed to shorten the time of transfusion-dependent thrombocytopenia in a previous study. In this multicenter, randomized, placebo-controlled, double-blind study we determined the effect of administration of PEG-rHuMGDF prior to CT and of administration prior, concurrent, and 1 day post CT on platelet recovery and transfusion requirements in patients receiving consolidation CT for de novo AML. Patients were randomized to receive either 30 microk/kg PEG-rHuMGDF as a single dose on day -6 ( n=37), placebo as a single dose on day -6 ( n=9), 30 microk/kg PEG-rHuMGDF administered on day -6 followed by 10 microg/kg on days -5 to day 6 (through CT and including the day after CT, n=35), or placebo administered on day -6 to day 6 ( n=9). The median times to transfusion-independent platelet recovery to >20x10(9)/l were 24.5 and 24.0 days in the PEG-rHuMGDF day -6 group and PEG-rHuMGDF day -6 to 6, respectively, compared to 21.0 days in the placebo group. There were no significant differences in the number of days of platelet transfusions between either PEG-rHuMGDF schedule or placebo. The PEG-rHuMGDF day -6 to 6 group had a delayed absolute neutrophil count (ANC) recovery compared to either placebo or PEG-rHuMGDF day -6 treated patients. Thus, alteration of the scheduling of PEG-rHuMGDF in terms of earlier dosing before and during chemotherapy did not improve platelet recovery but rather delayed hematopoietic reconstitution. Although unexpected, these observations may be of major relevance for the design of future clinical trials with recombinant thrombopoietins.

Adult↗
PubMed2003

[A case of symptomatic paroxysmal kinesigenic dsykinesia with primary central nervous system lymphoma].

Paroxysmal dyskinesias are rare movement disorders. In one fourth of cases, a symptomatic cause can be found, e.g., brain ischemia or inflammatory diseases. We report a unique case of secondary paroxysmal kinesigenic dyskinesia (PKD). The 37-year-old patient suffered from a primary CNS lymphoma invading the right thalamus. Consecutively, he showed dystonic-athetoid movements in the left half of the body. The involuntary movements had a duration of approximately 20 s and occurred more than 100 times per day. Carbamazepine treatment showed excellent results. This is the first reported case of a symptomatic paroxysmal dyskinesia induced by a primary CNS lymphoma.

Adult↗
PubMed2003

Recombinant factor VIII expression in hematopoietic cells following lentiviral transduction.

Autologous transplantation of gene-modified hematopoietic stem cells may provide a therapeutic strategy for several monogeneic disorders. In previous studies, retroviral gene transfer of coagulation factor VIII (FVIII) into FVIII(-/-) mouse bone marrow (BM) cells did not result in detectable plasma FVIII levels. However, specific immune tolerance was achieved against neo-antigenic FVIII. Here, we used lentiviral vectors to study the ability of various hematopoietic cell types to synthesize and secrete recombinant FVIII. Several myeloid, monocytic and megakaryocytic cell lines (K-562, TF-1, Monomac-1, Mutz-3, Meg-01) expressed FVIII at 2-12 mU/10(4) cells. In contrast, two lymphatic cell lines, BV-173 and Molt-4, were less-efficiently transduced and did not express detectable FVIII. Similarly, peripheral blood-derived primary monocytes were transduced efficiently and expressed up to 20 mU/10(4) cells, whereas primary lymphocytes did not express FVIII. Although human and canine CD34(+) cells were transduced efficiently, the cells expressed very low levels of FVIII (up to 0.8 mU/10(4) cells). Following xenotransplantation of transduced CD34(+) into NOD/SCID mice, ELISA failed to detect FVIII in the plasma of engrafted mice. However, NOD/SCID repopulating cell (SRC)-derived human monocytes isolated from BM of these mice secreted functional recombinant FVIII after culture ex vivo. Again, SRC-derived human lymphocytes did not secrete FVIII. Therefore, certain hematopoietic cell types are able to synthesize and secrete functional recombinant FVIII. Our results show for the first time that transplantation of transduced CD34(+) progenitors may give rise to differentiated hematopoietic cells secreting a nonhematopoietic recombinant protein.

Animals↗
PubMed2003

The emergence of a C/EBPalpha mutation in the clonal evolution of MDS towards secondary AML.

Recently, mutations in the transcription factor CCAAT/ enhancer binding protein alpha (C/EBPalpha) have been described in acute myeloid leukemia (AML). We performed a mutational analysis of the C/EBPalpha gene in the myelodysplastic syndromes and AML with antecedent MDS. No mutations were found in patients with refractory anemia (0/27), refractory anemia with ringed sideroblasts (0/7), refractory anemia with excess of blasts (RAEB 0/16) or chronic myelomonocytic leukemia (CMML 0/5). One out of 13 patients with RAEB-T/AML secondary to MDS showed a mutation in the C/EBPalpha gene. In this patient a 4 bp insertion disrupted codon 69 in one allele. This novel +1 frame shift is predicted to result in a truncated protein of 107 amino acids. However, the dominant protein translated was the C/EBPalpha isoform p30, which was previously shown to inhibit the DNA-binding and transactivation properties of C/EBPalpha p42. Interestingly this mutation could not be detected at diagnosis in the initial RAEB and RAEB-T stage. The mutation appeared at relapse after chemotherapy for RAEB-T. We conclude that the C/EBPalpha mutation was not essential for the initial blast accumulation. The emergence of a bast clone carrying a C/EBPalpha mutation at relapse indicates that this mutation may confer a growth advantage in a myeloid cell with an established differentiation block.

Adult↗
PubMed2003

Aberrant methylation and impaired expression of the p15(INK4b) cell cycle regulatory gene in chronic myelomonocytic leukemia (CMML).

The important cell cycle regulatory gene p15(INK4b) has been shown to be inactivated in acute myeloid leukemia and myelodysplastic syndrome. Little is known about the expression and epigenetic modification of this gene in chronic myelomonocytic leukemia (CMML) that belongs to the myelodysplastic/myeloproliferative disorders (MDS/MPD) with a high proportion of blastic transformation. Analysis of bone marrow trephines in a series of 33 CMML cases showed an aberrant p15(INK4b) gene methylation in up to 58% of cases. Methylation was analyzed employing different methylation-specific PCR and genomic sequencing protocols. It turned out to be spread over a broad area of the 5' region and exhibited substantial heterogeneity between cases and even in individual patients. The degree of aberrant methylation was correlated with a reduced mRNA as well as reduced protein expression, and was associated with a higher expression of DNA methyltransferase DNMT 3A. We conclude that aberrant gene methylation is a frequent event in CMML that might contribute to the pathogenesis of this MDS/MPD.

Bone Marrow↗
PubMed2003

Synergistic cytotoxic effects in myeloid leukemia cells upon cotreatment with farnesyltransferase and geranylgeranyl transferase-I inhibitors.

As deregulation of RAS signaling is important in the pathogenesis of myeloid leukemias, molecular targeting of RAS signaling may be a promising therapeutic strategy. Farnesyl transferase inhibitors (FTIs) are the most promising class of these new cancer therapeutics. Several FTIs have entered phase II clinical trials in acute myeloid leukemia (AML). Since geranylgeranylation of K-RAS and N-RAS in the presence of FTIs may represent an important mechanism of FTI resistance, 6 geranylgeranyl transferase-I inhibitors (GGTIs) were screened alone and in combination with FTI for growth inhibition of myeloid leukemia cells. Significant growth inhibition (>70%) in myeloid cell lines was observed for GGTI-286 (9/19), GGTI-298 (14/19), GGTI-2147 (16/19) and FTI L-744,832 (17/17). GGTI treatment of NB-4 cells resulted in an accumulation of cells in G(0)/G(1), whereas FTI L-744,832 primarily caused an increase in G(2)/M. FTI and GGTIs both induced apoptosis. In all cases, FTI/GGTI cotreatment led to synergistic cytotoxic effects in both myeloid cell lines (5/5) and primary AML cells (6/6). This synergy coincided with increased apoptosis. FTI/GGTI cotreatment caused an accumulation of unprocessed N-RAS and inactive N-RAS-RAF complexes. Our results suggest that alternative geranylgeranylation of N-RAS may represent an important mechanism of resistance to FTI monotherapy in myeloid leukemia cells.

Adult↗
PubMed2003

Therapeutic efficacy of prenylation inhibitors in the treatment of myeloid leukemia.

Farnesyltransferase inhibitors (FTIs) represent a new class of anticancer agents that specifically target post-translational farnesylation of various proteins that mediate several cellular processes such as signal transduction, growth, differentiation, angiogenesis and apoptosis. These compounds were originally designed to block oncogenic RAS-induced tumor growth by impeding RAS localization to the membrane, but it is now evident that FTIs also affect processing of several other proteins. The need for novel therapies in myeloid leukemia is underscored by the high rate of treatment failure due to high incidences of relapse- and treatment-related toxicities. As RAS deregulation is important in the pathogenesis of myeloid leukemias, targeting of RAS signaling may provide a new therapeutic strategy. Several FTIs (eg BMS-214662, L-778,123, R-115777 and SCH66336) have entered phase I and phase II clinical trials in myeloid leukemias. This review discusses recent clinical results, potential combination therapies, mechanisms of resistance and the clinical challenges of toxicities associated with prenylation inhibitors.

Alkyl and Aryl Transferases↗
PubMed2002

In vitro response of myelodysplastic megakaryocytopoiesis to megakaryocyte growth and development factor (MGDF).

To evaluate a potential therapeutic role for megakaryocyte growth and development factor (MGDF) in myelodysplastic syndromes (MDS) we compared the in vitro response of normal and myelodysplastic megakaryopoiesis to MGDF on bone marrow mononuclear cells from nine MDS patients and four healthy donors in a short term liquid culture system. The cells were incubated with MGDF alone (1 ng/ml, 10 ng/ml and 100 ng/ml) and in combination with 20 ng/ml stem cell factor, 2 U/ml erythropoietin (EPO) and 100 ng/ml interleukin-3 (IL-3). Cytospins were prepared after 4 days and 10 days for CD61 APAAP staining. In addition, the ploidy of propidium iodide stained CD61 positive cells were detected by flow cytometry. The CD61+ cell number significantly increased (13-fold after 4 days, 56-fold after 10 days of culture) when MGDF (100 ng/ml) was added to the normal bone marrow (NBM) cultures (P=0.0003; P=0.0001). In the MDS cultures the absolute number of endomitotic cells as well as the percentage of polyploid cells remained significantly lower than in NBM after 10 days (P=0.0001). The effect of MGDF on polyploidization of MDS cells was significantly dose dependent (P=0.0051). We found no correlation between peripheral platelet count, cellularity of the bone marrow, number of bone marrow megakaryocytes or FAB-subtype and response to MGDF. Additional administration of IL-3 resulted in a left-shift of megakaryopoiesis in both groups. Even though the response of myelodysplastic megakaryocytic progenitors to MGDF shows inter-individual variations, it is significantly impaired overall. Our data suggest that higher doses of MGDF may be able to ameliorate thrombocytopenia in a subgroup of MDS patients.

Aged↗
PubMed2002

Prospective randomized trial to evaluate two delayed granulocyte colony stimulating factor administration schedules after high-dose cytarabine therapy in adult patients with acute lymphoblastic leukemia.

In acute lymphoblastic leukemia (ALL), treatment with granulocyte colony stimulating factor (G-CSF) during remission induction shortens granulocytopenia and may decrease morbidity due to infections. However, the optimal timing of G-CSF administration after chemotherapy is not known. In a prospective randomized multi-center study, adult ALL patients were treated with high-dose ARA-C [HDAC, 3 g/m(2) bid (1 g/m(2) bid for T-ALL) days 1-4] and mitoxantrone (MI 10 mg/m(2) days 3-5). They were randomized to receive recombinant human G-CSF (Lenograstim) 263 micro g/day SC starting either from day 12 (Group 1) or day 17 (Group 2). Fifty-five patients (41 male, 14 female) with a median age of 34 years (range: 18-55 years) were enrolled into the study; 50 patients were evaluable. The median duration of neutropenia <500/ micro l after HDAC/MI was 12 days (range: 7-22 days) in the early G-CSF Group 1 and also 12 days (range: 4-22 days) in the late G-CSF Group 2; this was shorter than in the historical control group (15 days, range: 4-43 days, n=46) where the patients received identical cytotoxic treatment without G-CSF. Seventeen infections were observed in 14 patients in Group 1 (47%) and 13 infections in 10 patients in Group 2 (50%) compared to 27 infections in 49 patients of the historical control (54%). In Group 1, the patients received a median of 11 injections with G-CSF (range: 7-22) compared to 7 injections (range: 4-19) in Group 2. The total administered dose of G-CSF in Group 2 was significantly reduced by 40% ( P<0.0001). The delayed start of G-CSF after HDAC/MI in ALL achieves the same clinical benefit compared to the earlier initiation of G-CSF. The reduction of treatment costs by reducing the total G-CSF dose may be important in future treatment with this hematopoietic growth factor.

Adolescent↗
PubMed2002

Evaluating the prognosis of patients with myelodysplastic syndromes.

One of the hallmarks of myelodysplastic syndromes (MDS) is their prognostic heterogeneity which complicates decision making regarding treatment for individual patients. The French-American-British (FAB) classification provides significant prognostic information, but carries the disadvantage of arbitrary demarcation of subgroups and overemphasis of morphological findings. In addition, there is considerable variation in survival and risk of acute myeloblastic leukemia (AML) development even within defined FAB subgroups, particularly in patients with refractory anemia with ring sideroblasts (RARS) and chronic myelomonocytic leukemia (CMML). Over the last 2 decades, several research groups have tried to identify additional clinical, hematological, and cell biological parameters in order to more accurately predict the natural course of MDS. These investigations have clarified that the number and extent of peripheral blood cytopenias, the bone marrow blast count, and the cytogenetic pattern are the most powerful prognostic indicators in MDS. Recent efforts have been directed at constructing prognostic scoring systems. These scoring systems try to enhance the predictive power by combining several features of the disease, which have proved their independent prognostic weight on multivariate analysis. The International MDS Risk Analysis Workshop substantially advanced the prognostic categorization of MDS patients by proposing a new scoring system (International Prognosis Scoring System, IPSS) that can be successfully applied to risk assessment of newly diagnosed patients and will likely prove useful for the design and analysis of therapeutic trials in MDS.

Bone Marrow↗
PubMed2002

Clinical phase II study and pharmacological evaluation of rubitecan in non-pretreated patients with metastatic colorectal cancer-significant effect of food intake on the bioavailability of the oral camptothecin analogue.

A randomised, open label phase II study was performed in patients with advanced colorectal cancer to evaluate the safety, toxicity and antineoplastic activity of the topoisomerase I-inhibitor rubitecan. A cross-over design was chosen to determine the intrapatient variation of the bioavailability and pharmacokinetics of the anticancer agent depending on the timing of food intake in relation to the oral drug administration. Patients with previously untreated metastatic disease received two single oral doses of rubitecan 1.5 mg/m2 for assessment of the pharmacokinetics. They were randomised to have the first administration either after an overnight fasting period or immediately after a high calorie breakfast, and crossed over to the alternative schedule after a one-week washout period. After completion of the pharmacokinetic sampling, treatment continued with rubitecan given orally at a dose of 1.5 mg/m2/day, to be increased up to 2.0 mg/m2/day, under fasting conditions for 5 consecutive days per week until disease progression. 19 patients entered the trial after informed consent was obtained. A total number of 35 treatment cycles (median 2, range 1-4) were administered. All patients were evaluable for safety. The toxicity profile of rubitecan was generally mild to moderate, with sporadic cases of grade 4 toxicities (Common Toxicity Criteria (CTC) version 2.0) diarrhoea, leucopenia and neutropenia. None of 15 evaluable patients achieved an objective response. The majority had early disease progression. 14 patients were evaluable for pharmacokinetic analysis. The bioavailability of rubitecan was found to be strongly dependent on the timing of food intake with a fasted-to-fed ratio for C(max) of 1.98 (two-tailed P<0.001; ANOVA), T(max) 0.49 (P<0.001), AUC(0-8 h) 2.52 (P<0.001) and AUC(0-24 h) 1.64 (P=0.003). Rubitecan is well tolerated, but clinically inactive in colorectal cancer at the currently recommended dose and schedule. The bioavailability is strongly dependent on the timing of food intake in relation to the oral administration of the drug. The topoisomerase I-inhibitor should be administered under fasting conditions to achieve adequate drug exposure in future prospective trials in other tumour types.

Administration, Oral↗
PubMed2002

Favourable response to antithymocyte or antilymphocyte globulin in low-risk myelodysplastic syndrome patients with a 'non-clonal' pattern of X-chromosome inactivation in bone marrow cells.

OBJECTIVE: Antithymocyte and antilymphocyte globulin (ATG/ALG) have a therapeutic effect in about 30% of patients with myelodysplastic syndromes (MDS). We were interested to know whether responding patients achieve clonal or polyclonal remissions. PATIENTS: Ten women with low-risk MDS received either ALG or ATG. Before treatment and 3, 6, and 12 months later, X-chromosome inactivation patterns of peripheral blood T lymphocytes were compared with those of peripheral blood granulocytes or bone marrow cells, using the human androgen receptor gene assay and the phosphoglycerate kinase-1 assay. RESULTS: Six women did not respond to therapy. Prior to treatment, four of them had a monoclonal, one had an oligoclonal, and one had a skewed X-chromosome inactivation pattern (XCIP). Four patients responded to ATG/ALG. Three of them were informative in our X-inactivation assays, and showed a non-clonal XCIP which did not change significantly after treatment with ATG/ALG. CONCLUSION: A non-clonal XCIP in the bone marrow was associated with a response to ATG/ALG. Non-clonal XCIPs do not necessarily imply that there is no pathological clone. By definition, they just indicate that there is no evidence of a clone contributing more than 50% of cells in a sample. Non-clonal XCIPs may therefore be attributable to incomplete clonal expansion. This, in turn, might be explained by a vigorous immune attack against the MDS clone, which simultaneously causes collateral damage in the remaining normal haemopoiesis. In such patients, ATG/ALG may improve normal haemopoiesis by relieving the immunological pressure on the innocent bystanders.

Aged↗