Value of high-dose cytarabine during interval therapy of a Berlin-Frankfurt-Munster-based protocol in increased-risk children with acute lymphoblastic leukemia and lymphoblastic lymphoma: results of the European Organization for Research and Treatment of Cancer 58881 randomized phase III trial.
(33/487)
PURPOSE: The European Organization for Research and Treatment of Cancer 58881 study was designed to test in a prospective multicentric randomized trial the value of high-dose (HD) intravenous (IV) cytarabine (Ara-C) added to HD IV methotrexate (MTX) to reduce the incidence of CNS and systemic relapses in children with increased-risk acute lymphoblastic leukemia (ALL) or stage III and IV lymphoblastic lymphoma treated with a Berlin-Frankfurt-Munster (BFM)-based regimen. PATIENTS AND METHODS: After completion of induction-consolidation phase, children with increased-risk (risk factor > 0.8 or T-lineage) ALL or stage III and IV lymphoblastic lymphoma were randomized to receive four courses of HD MTX (5 g/m(2) over 24 hours every 2 weeks) and four intrathecal administrations of MTX (Arm A) or the same treatment schedule with additional HD IV Ara-C (1 g/m(2) in bolus injection 12 and 24 hours after the start of each MTX infusion) (Arm B). RESULTS: Between January 1990 and January 1996, 653 patients with ALL (593 patients) or lymphoblastic lymphoma (60 patients) were randomized: 323 were assigned to Arm A (without Ara-C) and 330 to Arm B (with Ara-C). A total of 190 events (177 relapses and 13 deaths without relapse) were reported, and the median follow up was 6.5 years (range, 2 to 10 years). The incidence rates of CNS relapse were similar in both arms whether isolated (5.6% and 3.3%, respectively) or combined (5.3% and 4.6%, respectively). The estimated 6-year disease-free survival (DFS) rate was similar (log-rank P =.67) in the two treatment groups: 70.4% (SE = 2.6%) in Arm A and 71.0% (SE = 2.5%) in Arm B. The 6-year DFS rate was similar for ALL and LL patients: 70.2% (SE = 1.9%) versus 76.3% (SE = 5.6%). CONCLUSION: Prevention of CNS relapse was satisfactorily achieved with HD IV MTX and intrathecal injections of MTX in children with increased-risk ALL or stage III and IV lymphoblastic lymphoma treated with our BFM-based treatment protocol in which cranial irradiation was omitted. Disappointingly, with the dose schedule used in this protocol, HD Ara-C added to HD MTX, although well tolerated, failed to further decrease the incidence of CNS relapse or to improve the overall DFS. (+info)
Preliminary crystallographic studies of Y25F mutant of periplasmic Escherichia coli L-asparaginase.
(34/487)
Periplasmic Escherichia coli L-asparaginase II with Y25F mutation in the active-site cavity has been obtained by recombinant techniques. The protein was crystallized in a new hexagonal form (P6(5)22). Single crystals of this polymorph, suitable for X-ray diffraction, were obtained by vapor diffusion using 2-methyl-2,4-pentanediol as precipitant (pH 4.8). The crystals are characterized by a = 81.0, c = 341.1 A and diffract to 2.45 A resolution. The asymmetric unit contains two protein molecules arranged into an AB dimer. The physiologically relevant ABA'B' homotetramer is generated by the action of the crystallographic 2-fold axis along [1, -1, 0]. Kinetic studies show that the loss of the phenolic hydroxyl group at position 25 brought about by the replacement of Y with F strongly impairs kcat without significantly affecting Km. (+info)
Outcomes of treatment of children and adolescents with recurrent non-Hodgkin's lymphoma and Hodgkin's disease with dexamethasone, etoposide, cisplatin, cytarabine, and l-asparaginase, maintenance chemotherapy, and transplantation: Children's Cancer Group Study CCG-5912.
(35/487)
PURPOSE: To determine the toxicity and response rate in children treated with dexamethasone, etoposide, cisplatin, high-dose cytarabine, and L-asparaginase (DECAL) for recurrent non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). PATIENTS AND METHODS: Ninety-seven children with recurrent NHL (n = 68) or HD (n = 29) were enrolled. Treatment consisted of two cycles of DECAL, then bone marrow transplantation or up to four cycles of ifosfamide, mesna, and etoposide alternating with DECAL maintenance therapy. RESULTS: After two cycles of DECAL induction therapy, complete response (CR) or partial response (PR) was reported in 19 (65.5%; 10 CRs and nine PRs) of 29 patients with HD and 29 (41.6%; 23 CRs and six PRs) of 68 patients with NHL. When only 24 patients with HD and 58 patients with NHL who were assessable for response were considered, the response rates were 79.2% (19 of 24 patients) and 50.0% (29 of 58 patients), respectively. Five-year event-free survival was 26% +/- 9% and 23% +/- 5% in patients with HD and NHL, respectively. Five-year survival was 31% +/- 14% and 30% +/- 6%, respectively. Although median time to treatment failure was significantly longer in patients with HD (EFS, P =.002; survival, P =.011), this difference did not translate into a higher long-term survival. Grade 3 or 4 toxic effects were observed during induction in 70 (72%) of 97 patients and during maintenance in 45 (70%) of 64 courses of DECAL therapy. Pancytopenia and systemic infections in particular were frequently observed. Other toxic effects were uncommon. Although not a formal part of the therapy or the study design, 42 patients who responded to therapy who underwent bone marrow transplant did not show any benefit from this approach. CONCLUSION: DECAL is an effective and tolerable salvage regimen for treating patients with recurrent NHL and HD. (+info)
Treatment of childhood acute lymphoblastic leukemia. Long-term results of the AIEOP-ALL 87 study.
(36/487)
BACKGROUND AND OBJECTIVES: In March 1987 AIEOP started the AIEOP-ALL-87 study, based on the previous AIEOP-ALL-82. The aim of this new study was to evaluate, for all risk groups: a) the efficacy of treatment intensification achieved by adding a fourth drug (daunomycin) in the induction phase and a 3-drug reinduction phase for all risk groups; b) the impact of the addition of three doses of intrathecal methotrexate during cranial radiotherapy and extended exposure to weekly high-dose L-aspariginase during late intensification in high risk patients. We report the long-term results of the AIEOP ALL-87 study. DESIGN AND METHODS: From 1987 to 1991, a total of 632 eligible and evaluable children (age 1 to < or =16 years) with non-B-cell acute lymphoblastic leukemia (ALL), were enrolled and stratified as follows: standard risk (SR, 79 patients, 12.5%) had WBC <10,000/mm3, age > or = 3 and <7 years, and FAB L1 morphology. The high risk (HR, 175 patients, 27.7%) group included patients with WBC > or =50,000/mm3 or FAB L3 morphology or T immunophenotype or acute undifferentiated leukemia (AUL) or leukemia-lymphoma syndrome. All the remaining patients formed the intermediate risk group (IR, 378 patients, 59.8%). All patients received a 4-drug induction therapy; intermediate-dose methotrexate was given to HR patients; cranial radiotherapy was given to IR and HR patients, while SR patients received extended intrathecal methotrexate; all patients received a 3-drug reinduction phase; high dose L-asparaginase (HD-L-ASP; E.Coli, Bayer) was given to HR patients; continuation therapy with 6-mercaptopurine, i.m. methotrexate, and monthly vincristine and prednisone pulses was given to all patients. Treatment duration was 2 years. RESULTS: Six hundred and nineteen patients (97.9%) achieved complete remission. The remission rate was 98.7% in the SR group, 98.1% in the IR group, and 97.1% in the HR group. The overall 10-year survival and event-free survival (EFS) rates (SE) are 74.7% (1.8) and 62.8% (2.0) respectively; EFS rates by risk group are 67.5% (5.5) in SR, 62.8% (2.6) in IR, and 61.9% (3.8) for HR. The 10-year EFS for all eligible patients was 63.9% (1.9). INTERPRETATION AND CONCLUSIONS: When compared to the results of the AIEOP-ALL-82 study, treatment intensification in the ALL-87 study has improved long-term survival and EFS from 66.4% and 53.6% to 74.7% and 62.8%, respectively. Failures were mostly due to marrow or extramedullary relapses suggesting that further treatment intensification, as being used in current therapeutic strategies, is appropriate, although patients relapsing after less intensive treatment may have better chances of rescue. These results, although obtained in a relatively large proportion of patients, in which infants were not included, indicate that the addition of high-dose L-asparaginase to a relatively non-intensive treatment may be of major benefit for HR patients and that the addition of intrathecal methotrexate during CRT, may improve the central nervous system-disease control with a marked reduction of nervous system relapses. (+info)
Asparagine synthetase expression alone is sufficient to induce l-asparaginase resistance in MOLT-4 human leukaemia cells.
(37/487)
Childhood acute lymphoblastic leukaemia (ALL) is treated by combination chemotherapy with a number of drugs, always including the enzyme L-asparaginase (ASNase). Although the initial remission rate is quite high, relapse and associated drug resistance are a significant problem. In vitro studies have demonstrated increased asparagine synthetase (AS) expression in ASNase-resistant cells, which has led to the hypothesis that elevated AS activity permits drug-resistant survival. The data presented show that not only is elevated AS expression a property of ASNase-resistant MOLT-4 human leukaemia cells, but that short-term (12 h) treatment of the cells with ASNase causes a relatively rapid induction of AS expression. The results also document that the elevated expression of AS in ASNase-resistant cells is not fully reversible, even 6 weeks after ASNase removal from the culture medium. Furthermore, ASNase resistance, assessed as both drug-insensitive cell growth rates and decreased drug-induced apoptosis, parallels this irreversible AS expression. Mimicking the elevated AS activity in ASNase-resistant cells by overexpression of the human AS protein by stable retroviral transformation of parental MOLT4 cells is sufficient to induce the ASNase-resistance phenotype. These data document that ASNase resistance in ALL cells is a consequence of elevated AS expression and that although other drug-induced metabolic changes occur, they are secondary to the increased asparagine biosynthetic rate. (+info)
Multiple adaptive mechanisms affect asparagine synthetase substrate availability in asparaginase-resistant MOLT-4 human leukaemia cells.
(38/487)
Childhood acute lymphoblastic leukaemia is treated by combination chemotherapy with a number of drugs, almost always including the enzyme L-asparaginase (ASNase). Although the initial remission rate is quite high, relapse and associated drug resistance remain a problem. In vitro studies have demonstrated an adaptive increase in asparagine synthetase (AS) expression in ASNase-resistant cells, which is believed to permit ASNase-resistant human leukaemia cells to survive in vivo. The present results, obtained with ASNase-sensitive and -resistant human MOLT-4 leukaemia cell lines, illustrate that several other adaptive processes occur to provide sufficient amounts of the AS substrates, aspartate and glutamine, required to support this increased enzymic activity. In both cell populations, aspartate is derived almost exclusively from intracellular sources, whereas the necessary glutamine arises from both intracellular and extracellular sources. Transport of glutamine into ASNase-resistant cells is significantly enhanced compared with the parental cells, whereas amino acid efflux (e.g. asparagine) is reduced. Most of the adaptive change for the amino acid transporters, Systems A, ASC and L, is rapidly (12 h) reversed following ASNase removal. The enzymic activity of glutamine synthetase is also enhanced in ASNase-resistant cells by a post-transcriptional mechanism. The results demonstrate that there are several sites of metabolic adaptation in ASNase-treated leukaemia cells that serve to promote the replenishment of both glutamine and asparagine. (+info)
Hypermethylation of CpG islands in the mouse asparagine synthetase gene: relationship to asparaginase sensitivity in lymphoma cells. Partial methylation in normal cells.
(39/487)
We have sequenced the promoter region of the murine asparagine synthetase gene and examined its methylation profile in the CpG islands of L-asparaginase-sensitive 6C3HED cells (asparagine auxotrophs) and resistant variants (prototrophs). In the former, complete methylation of the CpG island is correlated with failure of expression of mRNA: cells of the latter possess both methylated and unmethylated alleles, as do cells of the intrinsically asparagine-independent lines L1210 and EL4. A similar phenomenon was seen in normal splenic cells of adult mice. This was age related: no methylation was found in weanlings, but up to 45% of gene copies in animals 18 weeks or older were methylated. It was also tissue related, with methylation occurring rarely in liver cells. The relationship of these changes to oncogenesis is considered. (+info)
Cell shrinkage and loss of cell viability by apoptosis have been examined in cultured CD95(Fas/Apo-1)-expressing leukemia-derived CEM and HL-60 cells subjected to acute deprivation of glutamine, a major compatible osmolyte engaged in cell volume control. Glutamine deprivation-mediated cell shrinkage promoted a ligand-independent activation of the CD95-mediated apoptotic pathway. Cell transfection with plasmids expressing FADD-DN or v-Flip viral proteins pointed to a functional clustering of CD95 receptors at the cell surface with activation of the 'extrinsic pathway' caspase cascade. Accordingly, cell shrinkage did not induce apoptosis in CD95 receptor-negative lymphoma L1210 cells. Replacement of glutamine with surrogate compatible osmolytes counteracted cell volume decrement and protected the CD95-expressing cells from apoptosis. A glutamine deprivation-dependent cell shrinkage with activation of the CD95-mediated pathway was also observed when asparaginase was added to the medium. Asparagine depletion had no role in this process. The cell-size shrinkage-dependent apoptosis induced by glutamine restriction in CD95-expressing leukemic cells may therefore be of clinical relevance in amidohydrolase enzyme therapies. (+info)