Search PubMed⌕ Search

Biomedical subjects

T Büchner

Publications and source records attributed to T Büchner.

At least 55 records · Page 3Linked to original sources
PubMed1999

Results of a randomized double-blind placebo-controlled trial evaluating sequential high-dose cytosine arabinoside/mitoxantrone chemotherapy with or without granulocyte/macrophage-colony-stimulating factor in high-risk myelodysplastic syndromes.

A prospective, randomized, double-blind placebo-controlled trial was designed to evaluate the impact of granulocyte/macrophage-colony-stimulating factor (GM-CSF) on the efficacy of sequential high-dose cytosine arabinoside/mitoxantrone chemotherapy (S-HAM) in adult patients with high-risk myelodysplastic syndromes (MDS). GM-CSF or placebo was given subcutaneously once daily at a dose of 250 microg/m2, starting 48 h prior to chemotherapy, and continued until neutrophil recovery. Owing to high toxicity and slow patient recruitement the study was closed and unblinded after 31 patients had been enrolled; 15 were randomized to receive placebo and 16 to receive GM-CSF. A total of 29 patients were evaluable for response; their median age was 57 years. Ten patients achieved a complete remission (34.5%), 9 patients had persistent MDS (31%), 10 patients died within 6 weeks after the onset of treatment (early death) (34.5%). The median remission duration was 190 days (range: 2.5-45 months). Among the 29 evaluable patients no significant differences could be found between the two study arms regarding complete remission rate [GM-CSF: 31% (5/16) versus placebo: 38% (5/13) P = 0.45], rate of persistent MDS [GM-CSF: 25% (4/16) versus 38% (5/13) P = 0.35), early death rate [44% (7/16) versus 23% (3/13) P = 0.22] and remission duration (GM-CSF: 87 days versus placebo 221 days). Duration of granulocytopenia (median: 33 days with GM-CSF) versus 35 days with placebo) and frequency of infectious episodes were not significantly influenced by GM-CSF. The small number of patients finally analyzed means that no definite conclusions about the effect of GM-CSF can be reached.

Adult↗
PubMed1999

Clinical significance of CD95, Bcl-2 and Bax expression and CD95 function in adult de novo acute myeloid leukemia in context of P-glycoprotein function, maturation stage, and cytogenetics.

Resistance to chemotherapy-induced apoptosis and a multidrug-resistance (MDR) phenotype, mainly mediated by P-glycoprotein (P-gp), contribute to chemotherapy failure in hematologic malignancies. To study apoptosis-regulating factors in acute myeloid leukemia (AML), we investigated cell samples of adults with de novo AML by flow cytometry for constitutive expression levels of the apoptosis-related molecules CD95 (n = 135), Bcl-2 (n = 131), and Bax (n = 66), as well as spontaneous apoptosis in vitro (n = 104) and susceptibility to anti-CD95-induced apoptosis (CD95 sensitivity) (n = 93). We correlated these findings with P-gp function as detected by the rhodamine123-efflux test (n = 121), immunophenotype, FAB morphology, cytogenetics, and clinical data of the examined patients. Immature FAB M0/1 AML cells expressed significantly more Bcl-2 (P < 0.0002) and less CD95 (P < 0.0003) compared with AML cells of the more mature FAB M2-5 subtypes. No maturation-dependent difference in Bax expression was observed. FAB M2-5 AML cells were more susceptible to anti-CD95-induced apoptosis (P < 0.008) and showed a lower P-gp function (P < 0.002) than FAB M0/1 AML cells. Leukemic cells of AML patients who achieved a complete remission (CR) after induction chemotherapy expressed less Bcl-2 than non-responder (NR) (69 CR, 23 NR; P = 0.05). CR was associated with a higher extent of spontaneous apoptosis in vitro (58 CR, 17 NR; P=0.05) and a tendency towards a higher CD95 expression (73 CR, 23 NR; P = 0.08) compared to NR. CR also correlated with a low P-gp function (70 CR, 21 NR; P = 0.008) and a tendency towards CD34 negativity (73 CR, 23 NR; P = 0.08). No correlation between Bax expression and response to induction chemotherapy (49 CR, 12 NR) was observed. In stepwise logistic regression analyses, P-gp function and the extent of spontaneous apoptosis in vitro as well as CD95 sensitivity but not Bcl-2, CD95, Bax, and CD34 expression levels emerged as significant markers for response to induction chemotherapy. We conclude that the constitutive expression of CD95 and Bcl-2, as well as CD95 sensitivity and P-gp function but not constitutive Bax expression depend on the maturation stage of leukemic cells in adult de novo AML. P-gp function, the extent of spontaneous apoptosis in vitro and CD95 sensitivity are more predictive for response to induction chemotherapy in adult de novoAML than the constitutive expression levels of the apoptosis-related molecules CD95, Bcl-2 and Bax.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Management of acute myeloid leukemia in elderly patients.

Acute myeloid leukemia (AML) at older age is associated with several biologic and clinical characteristics. Hence, it may arise from an early level of hematopoietic stem cells and has a high frequency of blast cells with multidrug resistance glycoprotein MDR1 expression and particularly a high incidence of poor prognostic karyotypes. These factors, rather than age per se, underlie the poorer outcome as compared with younger cases. Prospective randomized studies clearly demonstrate, however, that elderly patients benefit from more intensive induction therapy and particularly from full-dose application of anthracyclines and possibly also cytarabine. Hematopoietic growth factors accelerate the recovery from treatment-induced neutropenia and may improve the remission rate, remission duration, and even overall survival. New treatment strategies need to be developed, however, for poor-prognosis AML subtypes in order to further improve the therapeutic perspectives for elderly patients with AML.

Aged↗
PubMed1999

Expression of the C-kit receptor (CD117) is a feature of almost all subtypes of de novo acute myeloblastic leukemia (AML), including cytogenetically good-risk AML, and lacks prognostic significance.

Because of conflicting reports on the prognosis of patients with c-kit receptor positive AML and lacking correlations with cytogenetic analyses, we prospectively evaluated the c-kit receptor expression in 917 AML patients (750 adult patients; 167 children) using flow cytometry and compared the results to the immunophenotype, morphological and cytogenetic findings as well as clinical outcome. Expression of the c-kit receptor was present in 63% of all AML investigated. Among these an immature immunophenotype was more frequent and 30% had a CD34+/CD15- and 37% a CD34+/CD14- phenotype, whereas only 9% and 10% showed these phenotypes in the c-kit receptor negative group, respectively. C-kit receptor expression ranged average in M0 and M1 subtypes (69% versus 70%) but was less pronounced among M5 subtypes (21%). Results of karyotyping were available in 280 patients. C-kit receptor expression occurred in 37 of 42 (88%) patients with favorable cytogenetic abnormalities such as t(8;21), t(15;17) or inv(16) which exceeded the expression rate in patients with intermediate risk, poor risk or other abnormalities. Information about the clinical outcome was available in 228 patients treated according to the protocols of two German multicenter trials (AML-BFM, AMLCG). We found no difference of CR-rate or event-free survival (EFS) in adults with or without c-kit receptor expression. Children with c-kit receptor negative AML had a lower CR-rate and EFS, but also a lower median age and a higher frequency of M5 subtype as compared to children with c-kit receptor expression. In conclusion, analysis of c-kit receptor expression may help to identify phenotypically immature AML but fails to identify myeloid differentiation of leukemic blasts in approximately one third of patients. We found no evidence of an adverse prognosis in AML patients with c-kit receptor expression. Analysis for c-kit receptor expression does not appear to add information to established prognostic parameters in AML.

Adolescent↗
PubMed1999

Leukaemia-associated immunophenotypes (LAIP) are observed in 90% of adult and childhood acute lymphoblastic leukaemia: detection in remission marrow predicts outcome.

Analysis of differentiation antigens on leukaemic blasts is routinely done for diagnostic purposes, i.e. determination of stage of differentiation and lineage assignment. Acute lymphoblastic leukaemias are also frequently characterized by a leukaemia-associated immunophenotype (LAIP), either the coexpression of differentiation antigens physiologically restricted to other stages of differentiation (asynchronous LAIP) or cell lineages (aberrant LAIP). We defined LAIP in 241 consecutive unselected B-lineage (n = 193) and T-lineage (n = 48) ALL by three-colour flow cytometry using directly conjugated monoclonal antibodies. The incidence of LAIP was found to be 91.7%. In 63% of patients two to six leukaemia-associated expression patterns were detected. In order to study the specificity of LAIP in a therapy-relevant setting, remission bone marrow samples from patients with B-lineage ALL were analysed for the expression of T-lineage-associated phenotypes on the normal bone marrow cells and vice versa. The frequency of all T-lineage LAIP+ cells and all aberrant B-lineage LAIP+ cells was <1% in regenerating bone marrow samples at different timepoints. The incidence and clinical significance of LAIP+ cells was studied in 196 remission marrows of 70 ALL patients (55 remaining in CCR, 14 with bone marrow relapse, one with isolated CNS relapse). The presence of >1% LAIP+ at two consecutive timepoints predicted 5/8 bone marrow relapses in B-lineage ALL. The occurrence of LAIP+ cells >1% in T-lineage ALL after induction therapy predicted relapse in 7/7 cases. In conclusion, flow cytometric detection of LAIP+ cells appears to be a powerful tool for the prediction of outcome in ALL.

Adolescent↗
PubMed1999

Early empiric antifungal therapy of infections in neutropenic patients comparing fluconazole with amphotericin B/flucytosine.

We compared the efficacy and tolerability of fluconazole (FCA) with amphotericin B/flucytosine (ABF) in neutropenic patients with haematological malignancies. Antifungal therapy started on day 4 when fever was unresponsive to antibiotics or on day 1 together with the antibiotics, if there was evidence of mycosis. If patients did not respond to FCA after 7 days they switched to ABF. 98 patients, 51 FCA and 47 ABF were included in the study. Response to fever was achieved in 28/51 FCA patients and in another 16 after switching to ABF. So in overall 44/51 (86.2%) of the FCA and 37/47 (78.8%) of the ABF group defervescence was observed. 46 patients (21 FCA, 25 ABF) developed radiological signs of pneumonia. Resolution of infiltrates was achieved in 5/21 FCA and 20/25 ABF patients, and another 10 of 15 initially not responding patients showed regression when switched to ABF, 5 of these had highly suspected aspergillosis. Adverse events occurred in 19.6% of FCA and 97.9% of ABF patients. In conclusion fluconazole and amphotericin B/flucytosine seem to be equally effective. In view of its lower toxicity fluconazole may be preferred as first line empiric antifungal agent, but in case of nonresponse, pneumonia or aspergillosis it may be replaced by amphotericin B combined with flucytosine.

Adolescent↗
PubMed1998

Failure of fluconazole prophylaxis to reduce mortality or the requirement of systemic amphotericin B therapy during treatment for refractory acute myeloid leukemia: results of a prospective randomized phase III study. German AML Cooperative Group.

BACKGROUND: Invasive fungal infections have increasingly become a matter of concern with regard to patients receiving intensive myelosuppressive therapy for hematologic malignancies. Such infections, especially prolonged neutropenia systemic fungal infections, may contribute substantially to infectious complications and early death. Measures for early detection and effective prophylactic strategies using active and nontoxic antifungal agents are therefore urgently needed. METHODS: The current randomized study was initiated to assess the efficacy of oral fluconazole as systemic antifungal prophylaxis for high risk patients with recurrent acute myeloid leukemia undergoing intensive salvage therapy. RESULTS: Of 68 fully evaluable patients, 36 were randomized to fluconazole in addition to standard prophylaxis with oral co-trimoxazol, colistin sulphate, and amphotericin B suspension, and 32 were randomized to standard prophylaxis only. No major differences between the two groups were observed in the number of episodes of fever of unknown origin (61% vs. 50%) or clinically defined infections (56% vs. 50%). Microbiologically defined infections were more frequent in the fluconazole group (50% vs. 31%), mainly due to a higher incidence of bacteremias (42% vs. 22%). There were two cases of proven invasive fungal infections in each group. Systemic amphotericin B was administered more frequently to patients receiving fluconazole prophylaxis (56% vs. 28%). Fluconazole prophylaxis had no impact on the rate of early death or overall survival. CONCLUSIONS: For patients with high risk recurrent acute myeloid leukemia undergoing intensive salvage therapy, antifungal prophylaxis with fluconazole was not superior to standard prophylaxis only.

Acute Disease↗
PubMed1998

MLL and CALM are fused to AF10 in morphologically distinct subsets of acute leukemia with translocation t(10;11): both rearrangements are associated with a poor prognosis.

The translocation t(10;11)(p13;q14) has been observed in acute lymphoblastic leukemia (ALL) as well as acute myeloid leukemia (AML). A recent study showed a MLL/AF10 fusion in all cases of AML with t(10;11) and various breakpoints on chromosome 11 ranging from q13 to q23. We recently cloned CALM (Clathrin Assembly Lymphoid Myeloid leukemia gene), the fusion partner of AF10 at 11q14 in the monocytic cell line U937. To further define the role of these genes in acute leukemias, 10 cases (9 AML and 1 ALL) with cytogenetically proven t(10;11)(p12-14;q13-21) and well-characterized morphology, immunophenotype, and clinical course were analyzed. Interphase fluorescence in situ hybridization (FISH) was performed with 2 YACs flanking the CALM region, a YAC contig of the MLL region, and a YAC spanning the AF10 breakpoint. Rearrangement of at least one of these genes was detected in all cases with balanced t(10;11). In 4 cases, including 3 AML with immature morphology (1 AML-M0 and 2 AML-M1) and 1 ALL, the signals of the CALM YACS were separated in interphase cells, indicating a translocation breakpoint within the CALM region. MLL was rearranged in 3 AML with myelomonocytic differentiation (2 AML-M2 and 1 AML-M5), including 1 secondary AML. In all 3 cases, a characteristic immunophenotype was identified (CD4+, CD13-, CD33+, CD65s+). AF-10 was involved in 5 of 6 evaluable cases, including 1 case without detectable CALM or MLL rearrangement. In 2 complex translocations, none of the three genes was rearranged. All cases had a remarkably poor prognosis, with a mean survival of 9.6 +/- 6.6 months. For the 7 AML cases that were uniformly treated according to the AMLCG86/92 protocols, disease-free and overall survival was significantly worse than for the overall study group (P = .03 and P = .01, respectively). We conclude that the t(10;11)(p13;q14) indicates CALM and MLL rearrangements in morphologically distinct subsets of acute leukemia and may be associated with a poor prognosis.

Acute Disease↗
PubMed1998

Granulocyte colony-stimulating factor shortens duration of critical neutropenia and prolongs disease-free survival after sequential high-dose cytosine arabinoside and mitoxantrone (S-HAM) salvage therapy for refractory and relapsed acute myeloid leukemia. German AML Cooperative Group.

Patients with primary refractory or relapsed acute myeloid leukemia (AML) who undergo intensive salvage chemotherapy carry a high risk of treatment failure due to infectious complications and early relapses. The study presented here assessed the effect of granulocyte colony-stimulating factor (G-CSF) on the duration of post-treatment neutropenia, the incidence of infection-related deaths, and the disease-free and overall survival. Sixty-eight evaluable patients with relapsed and refractory AML received G-CSF 5 microg/kg per day subcutaneously starting 2 days after the completion of salvage treatment with the S-HAM regimen, consisting of high-dose cytosine arabinoside twice daily on days 1, 2, 8, and 9 and mitoxantrone on days 3, 4, 10, and 11. Ninety-one patients who were treated with the identical S-HAM regimen but without G-CSF support during a preceding study served as controls. The application of G-CSF resulted in a significant shortening of critical neutropenia of less than 500 microl (36 vs. 40 days; p = 0.008), which translated into a trend towards a lower early death rate (21% vs. 30%) and an increase of complete remissions (56% vs. 47%, p=0.11). In patients younger than 60 years a significant prolongation of time to treatment failure (159 vs. 93 days, p=0.038) and of duration of disease-free survival (203 vs. 97 days, p=0.003) was observed. These results indicate a beneficial effect of G-CSF on early mortality as well as on long-term outcome when administered after S-HAM salvage therapy for advanced AML.

Acute Disease↗
PubMed1998

[Intraocular lens implantation in childhood. Functional results and complications].

UNLABELLED: IOL implantation in childhood is still controversial. INTENTION: The purpose of this retrospective study was to evaluate functional results and complications in children after IOL implantation. METHODS AND RESULTS: Posterior chamber IOLs were implanted in 52 eyes of 45 children. Cataract extraction was necessary because of traumatic, congenital/developmental and secondary lens opacities. Nine IOLs were implanted in children between the ages of 1.9 and 4 years, 17 IOLs from 4 to 8 years and 26 IOLs in patients 8 to 14.3 years old. In 38 of the 52 eyes (73%) vision improved after the surgery. Fifty-four percent had an acuity of at least 0.5. The functional results of children more than 8 years old were superior to those of younger patients. Children with traumatic cataracts had better visual acuities than those with other types of cataract. Except for secondary capsular opacities (75%) that could not be prevented by performing a primary posterior capsulotomy or capsulectomy and iris capture (31%), postoperative complications were rare. CONCLUSION: Favorable functional results can be achieved by IOL implantation in children with cataracts. Many patients require secondary surgical procedures because of capsular opacities and iris capture.

Adolescent↗
PubMed1998

Microemboli are not a prerequisite in retinal artery occlusive diseases.

PURPOSE: Retinal artery occlusion (RAO) is caused by arterio-arterial or cardiovascular emboli in about 50% of all cases, but the role of non-embolic causes remains unclear. SUBJECTS AND METHODS: We studied 27 patients with amaurosis fugax (AFX), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and anterior ischaemic optic neuropathy (AION). Patients underwent an evaluation of cerebrovascular and cardiovascular risk factors, measurement of haemorheological parameters, and Doppler/duplex sonography including ultrasound detection of cerebral microembolic signals and echocardiography. RESULTS: Forty-one per cent of the patients had internal carotid atherosclerosis but only one patient had microembolic signals, probably due to a cardiac thrombus. Vascular risk factors, especially hypertension, were present in 82% of the patients correlating with abnormal haemorheological parameters such as increased thrombocyte reactivity. CONCLUSIONS: Our results indicate that altered haemorheological parameters, especially increased thrombocyte reactivity and vascular risk factors such as arterial hypertension, are non-embolic causes of vascular disease in a significant number of patients with RAO. This should guide diagnostic and therapeutic considerations concerning RAO in cases without proven embolic sources.

Adult↗
PubMed1998

Quality of life in adult patients with acute myeloid leukemia receiving intensive and prolonged chemotherapy -- a longitudinal study.

Intensification of treatment for acute myeloid leukemia (AML) in adult patients resulted in a substantial improvement in long-term prognosis. Therefore, the assessment of quality of life (QL) of patients undergoing treatment is of growing interest. This study was designed to evaluate QL in patients with AML treated according to the protocol of the German AML-Cooperative Group (Münster, Germany). The EORTC QLQ-C 30 questionnaire was used to analyze QL throughout therapy, evaluating defined specific parameters at 12 different time-points. Sixty-one patients were recruited within the first 30 months of the study. Those 28 patients who have completed the course of inpatient treatment (n=28) are evaluated for changes in the conceptually distinct QL domains: Physical Functioning (P<0.001), Role Functioning (P=0.001), Emotional Functioning (P < 0.001) and Social Functioning (P=0.007) improve significantly from beginning of chemotherapy to the end of inpatient treatment. Individual assessment of Global Health Status and Subjective QL improves significantly over the same time (P< 0.001). At the end of inpatient treatment patients suffer significantly less from fatigue, nausea/emesis, loss of appetite and sleep disturbance (P < 0.001). Although most patients with AML eventually relapse, the evaluation of QL in patients undergoing treatment shows that subjective benefit outweighs the adverse effects of antileukemic therapy.

Acute Disease↗
PubMed1998

Superiority of high-dose over intermediate-dose cytosine arabinoside in the treatment of patients with high-risk acute myeloid leukemia: results of an age-adjusted prospective randomized comparison.

Although cytosine arabinoside (AraC) represents the most effective single agent in the treatment of adults with acute myeloid leukemia (AML) when given at doses exceeding 200 to 500 mg per application, its optimal dosage is still a matter of controversial discussion. While pharmacokinetic investigations suggest that the AraC-activating enzyme deoxycytidine kinase is saturated at drug concentrations achieved by short-term infusion of 0.5 to 1.0 g/m2 AraC and that higher doses are therefore not more effective, recent evidence indicates that additional mechanisms of AraC cytotoxicity may exist which could be enhanced by further dose escalation. In order to test this thesis in the clinical setting, a prospective randomized comparison of high-dose (HD-AraC) vs intermediate-dose (ID-AraC) AraC was carried out in patients with refractory or relapsed AML on the basis of the sequential high-dose AraC and mitoxantrone regimen (S-HAM). AraC was given as a 3-h infusion q 12 h on days 1, 2, 8 and 9. Patients younger than 60 years were randomized to AraC doses of 3.0 g/m2 vs 1.0 g/m2 while older patients received either 1.0 g/m2 or 0.5 g/m2 per single dose. Mitoxantrone was given to all patients on days 3, 4, 10 and 11 at a daily dose of 10 mg/m2. Randomization was stratified for primary refractoriness against induction therapy and length of first remission in relapsed patients. From 186 evaluable patients, 88 (47%) and 10 cases (5%) achieved a complete (CR) or partial (PR) remission, 39 patients (21%) had persisting leukemia (non-response (NR)), and 49 cases (26%) died within 6 weeks after the start of therapy (early death (ED)). In patients younger than 60 years the higher dose level resulted in a significant reduction of NR (12% vs 31%; ordinal chi2 test: P = 0.01) but also a higher rate of ED (32% vs 17%) thus leading to a marginally higher CR rate only (52% vs 45%). Within the subgroup of patients with refractory AML the tendency towards a higher CR rate after HD-AraC was more pronounced (46% vs 26%; P = 0.045). In patients older than 60 years, corresponding though less evident differences were observed with a higher rate of NR in the lower dose group (26% vs 16%) and ED occurring more frequently after higher doses (36% vs 26%). These data indicate that HD-AraC reveals a significantly higher antileukemic efficacy than ID-AraC as expressed by a significant reduction of failure from NR. This advantage, however, does not fully translate into an increase in remission rate due to a higher incidence of ED after HD-AraC predominantly from uncontrolled infections. In order to take full advantage of the higher antileukemic activity of HD-AraC an improvement of supportive care and infection control is warranted.

Acute Disease↗
PubMed1998

Combination of aclarubicin and etoposide for the treatment of advanced acute myeloid leukemia: results of a prospective multicenter phase II trial. German AML Cooperative Group.

In order to develop new strategies for the treatment of relapsed or refractory acute myeloid leukemia, the German AML Cooperative Group performed a prospective multicenter phase II study to evaluate the antileukemic efficacy of aclarubicin 60 mg/m2/day and etoposide 100 mg/m2/day each given for 5 days. Of 37 heavily pretreated evaluable patients (median age 42 years, range 18-81) 15 (40%) achieved a remission after one or two courses of treatment consisting of nine complete (24%) and six partial remissions (16%). Fourteen (38%) cases were non-responders and eight (22%) patients suffered from early deaths. Disease-free survival for patients in remission and overall survival were 3.2 months each. The median duration of critical neutropenia <500/microl was 27 days. The most frequent non-hematologic side-effects were stomatitis (WHO III/IV, 48%), infections (40%), nausea/vomiting (26%) and diarrhea (24%). Cardiac toxicity was mild. This study suggests a substantial antileukemic efficacy and an acceptable toxicity of aclarubicin in combination with etoposide in heavily pretreated patients with advanced acute myeloid leukemia, and warrants further evaluations in a more favorable stage of the disease.

Aclarubicin↗
PubMed1998

Correlation of cytogenetic, molecular cytogenetic, and clinical findings in 59 patients with ANLL or MDS and abnormalities of the short arm of chromosome 12.

Abnormalities of the short arm of chromosome 12 (12p) are found in about 5% of acute nonlymphocytic leukaemias (ANLL) and myelodysplastic syndromes (MDS). They are described to be characteristic of secondary leukaemias, especially after prior mutagenic exposure, and to be associated with a poor prognosis. In our series of 59 patients with 12p abnormalities and ANLL or MDS, exposure to genotoxic agents was proven only in five patients, but in 13/44 patients ANLL evolved from an MDS. Patients with a small deletion del(12)(p11.2p13) having a mild clinical course were distinguished from those with a large del(12)(p11.2), additional chromosomal anomalies, and a poor clinical course. Among the 31 patients with translocations or dicentric chromosomes involving 12p, a group of eight with t/dic(12;13) was the most frequent and was associated with a poor prognosis. The clinical outcome was adverse in the majority of patients with complex karyotype abnormalities, but in some patients a milder clinical course seems likely. A new, hitherto undescribed, abnormality in an MDS case with a duplication dup(12)(p11.2p13) was the amplification of the signal of the yeast artificial chromosome (YAC) clone 964c10 (D12S736). In 38 cases with deletions or unbalanced translocations/dicentrics one YAC signal was lost. Five patients with balanced translocations demonstrated breakpoints within the YAC, containing the ETV6 (TEL) gene. The breakpoints were telomeric to the YAC 964c10 in seven cases and centromeric in one patient.

Adult↗
PubMed1997

Activity of thymidine kinase and of polymerase alpha as well as activity and gene expression of deoxycytidine deaminase in leukemic blasts are correlated with clinical response in the setting of granulocyte-macrophage colony-stimulating factor-based priming before and during TAD-9 induction therapy in acute myeloid leukemia.

The present study was undertaken to assess the predictive value of pretherapeutic determinants of ara-C metabolism and proliferative activity of leukemic blasts for early response to antileukemic therapy in the setting of granulocyte-macrophage colony-stimulating factor (GM-CSF)-based priming before and during TAD-9 induction in 36 consecutive patients with de novo acute myeloid leukemia (AML). Ara-C metabolism was assessed by the activities of deoxycytidine kinase (DCK), deoxycytidine deaminase (DCD), DNA polymerase alpha (Poly alpha), and overall polymerase (overall Poly). The fraction of cells in S phase (%S phase) and thymidine kinase (TK) activity were determined as a measure of proliferative activity. Early response to therapy was defined by the percentage of leukemic blasts in the bone marrow 5 to 7 days after completion of TAD-9 with less than 5% signaling an adequate response and greater than 5% indicating an inadequate early reduction, respectively. While neither %S phase, DCK, nor overall Poly activity were predictive for early response, TK and Poly alpha activities were significantly higher for cases with adequate blast cell clearance. The respective median values were for TK 3.8 versus 1.85 pmol/min/mg protein (P = .012), and for Poly alpha 1.9 versus 0.69 pmol/min/mg protein (P = .014). An inverse relation was detected for DCD activity which was significantly lower in responding patients with a median of 0.33 nmol/min/mg protein (range, 0.0 to 29.5) as compared to a median of 5.1 nmol/min/mg protein (range, 0.11 to 8.45) in early nonresponders, (P = .009). Taking the respective median values as arbitrary cut-points for high or low enzyme activities, responders and nonresponders could be discriminated prospectively. Hence, 14 of 16 cases (88%) with DCD activities below the median of 1.56 nmol/min/mg protein responded as compared to only 3 of 14 (22%) patients with higher DCD activities (P = .0004). From the 15 patients with TK activity above the overall median of 3.2 pmol/min/mg protein, 11 cases (73%) achieved an adequate blast cell clearance while only 6 of 17 cases (35%) with lower values responded (P = .035). Similarly, 12 of 15 patients (80%) with high Poly alpha levels (>1.22 pmol/min/mg protein) responded to induction therapy as compared to only 5 of 14 patients (36%) with lower enzyme activities (P = .02). By logistic regression analysis of enzyme activities, DCD activity was found to be the most sensitive parameter to predict an adequate blast cell clearance (P = .032). Activities of DCD and TK were not only associated with initial response but were also found predictive for remission duration. Hence, from 11 patients with low TK levels 8 (73%) relapsed within 1 year, whereas only 2 of 11 (18%) patients with high TK activity experienced a recurrence of their disease (P = .015). Six of 9 (66%) patients with higher than median DCD levels relapsed within 1 year, whereas 10 of 14 patients (71%) with lower DCD levels had a longer remission duration (P = .085). Analysis of DCD gene expression at the mRNA level by a semi-quantitative reverse transcriptase-polymerase chain reaction method showed that a high transcription rate of the DCD gene was associated with high enzyme activities and vice versa. Hence, the observed intraindividual differences in DCD activity are a reflection of differences in gene activity and transcription rate rather than of variants in translation. Although further analyses are needed to elucidate the molecular mechanisms that determine the variation of enzyme activities in individual patients, the present study strongly suggests that pretherapeutic determination of TK and Poly alpha as well as of DCD allows to predict response to TAD-9 + GM-CSF induction therapy and may provide the means for the development of a risk adapted treatment strategy.

Acute Disease↗
PubMed1997

High antileukemic activity of sequential high dose cytosine arabinoside and mitoxantrone in patients with refractory acute leukemias. Results of a clinical phase II study.

BACKGROUND: The current study was initiated to assess the efficacy and side effects of a timed sequential application of high dose cytosine arabinoside (AraC) in combination with mitoxantrone (S-HAM) in patients with refractory acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). METHODS: Patients with refractory AML or ALL were eligible for S-HAM salvage therapy, which was comprised of AraC, 1 g/m2 or 3 g/m2 every 12 hours, on Days 1, 2, 8, and 9 and mitoxantrone, 10 mg/m2/day, given on Days 3, 4, 10, and 11. RESULTS: Of 22 fully evaluable patients, 14 patients (64%) achieved a complete remission whereas 5 patients (23%) succumbed to early death and 3 patients (14%) did not respond. Blood counts recovered at a median of 33.5 days after the start of treatment and complete remission was achieved after a median of 38 days. The median duration of complete remission was 4 months (range, 1-14 months) whereas overall survival time lasted for a median of 4.5 months (range, 1-30+ months). Treatment-associated toxicity was comprised predominantly of infection and diarrhea that reached World Health Organization Grades 3 and 4 in 64% and 32% of patients, respectively. Complementary pharmacokinetic evaluations of plasma AraC and AraU levels revealed no impact of initial AraC administration on the pharmacokinetics of subsequent AraC administrations and failed to demonstrate any evidence of self-potentiation. CONCLUSIONS: The clinical data show the S-HAM regimen to be a promising approach for the treatment of patients with advanced acute leukemias. However, further evaluation at earlier stages of treatment is needed.

Acute Disease↗