Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The treatment of acute myeloid leukemia (AML) in children with Down's syndrome (DS) has engendered considerable controversy. Because of the concerns for toxicity and increased rate of infections, treatment approaches varied considerably in the past with mixed results. However, experience on the recently completed Pediatric Oncology Group (POG) 8498 AML study suggests that DS children with AML constitute a distinct subgroup that responds well to therapy. Twelve of 285 children on POG 8498 (protocol for newly diagnosed AML) had DS. Children with DS and AML were predominantly male (9 of 12) and were quite younger at diagnosis (< 24 months in 10). The white blood cell count was less than 50 x 10(3)/microL in all 12 and French-American-British types M6 and M7 were frequent (5 of 12). An abnormal cytogenetic marker, in addition to constitutional trisomy 21, was present in 9 of 12 and involved chromosome 8 in 4 of 9. All cases studied (n = 5) were positive for myeloid cell surface markers (CD33, CD13, or CD11b) and, interestingly, were also positive for the CD7 antigen. Chemotherapy included daunorubicin, cytarabine (Ara-C), and 6-thioguanine for remission induction and featured high-dose Ara-C (3 g/m2 per dose) with or without L-asparaginase early in remission. Compared with children without DS, children with DS had a superior event-free survival (EFS at 4 years 100% v 28% +/- 6.2%; P = .003). The EFS remained superior even when compared with non-DS children less than 2 years of age with a white blood cell count less than 10 x 100,000/microL (100% v 48% +/- 17.3%; P = .01).
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PMID:Acute myeloid leukemia (AML) in Down's syndrome is highly responsive to chemotherapy: experience on Pediatric Oncology Group AML Study 8498. 849 50

In June 1984, the Pediatric Oncology Group (POG) initiated a pilot study (8498) using high-dose cytarabine (HdA; 3 g/m2) for intensification of early therapy in childhood acute myelogenous leukemia (AML) (group I). Remission induction therapy consisted of two courses of daunorubicin, cytarabine (Ara-C), and thioguanine (DAT). Postremission therapy consisted of four sequential courses, each consisting of (1) four doses of HdA (HdA4) followed by asparaginase (L-Asp), (2) etoposide (VP) plus azacytidine (Az), (3) prednisone, vincristine, methotrexate, and mercaptopurine (POMP), and (4) Ara-C daily for 5 days by continuous infusion. Six doses of intrathecal Ara-C were given for CNS prophylaxis. In December 1986, the protocol was amended (group II) to substitute six doses of HdA (HdA6) for the second DAT (two + five) induction course; postinduction, a single course of HdA6 was given instead of four HdA/L-Asp courses, and the remainder of the therapy was unchanged. One hundred forty group I patients and 145 group II patients were assessable. The two groups were similar with regard to clinical prognostic groups. No significant differences were noted in the two groups with regard to remission induction (85% [SE = 2%] in each group), induction deaths (6.5% v 7.0%), or deaths in remission (one in each group). Cerebellar toxicity was reported in three patients in group II (with HdA6) but none in group I (HdA4). At present, patients who received HdA6 (group II) had higher event-free survival than patients in group I (EFS at 3 years, 34% [SE = 11%] v 29% [SE = 4%]), and disease-free survival (DFS at 3 years, 42% [SE = 14%] v 34% [SE = 4%]), but the differences were not statistically significant. In both groups, children less than 2 years and those with WBCs less than 100,000/microL had significantly better outcome (EFS of 55% [SE = 10%] and 36% [SE = 5%] at 3 years, respectively) than children greater than or equal to 2 years and those with WBCs greater than or equal to 100,000/microL (EFS of 27% [SE = 5%] and 20% [SE = 9%] at 3 years, respectively.
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PMID:High-dose cytarabine for intensification of early therapy of childhood acute myeloid leukemia: a Pediatric Oncology Group study. 206 54

It is vital to develop effective therapy for children with acute lymphoblastic leukemia (ALL), in whom no remission occurs or who suffer relapse with current protocols. Cellular drug resistance is thought to be an important cause of induction failure and relapse. We performed in vitro tests of bone marrow samples in 196 children with newly diagnosed ALL with a 4-day culture and a methyl-thiazol-tetrazolium assay. We tested 16 drugs and calculated the 70% lethal dose (LD70) for 14 drugs and the leukemic cell survival (LCS) rate for dexamethasone and prednisolone. For each single drug, patients were classified into two groups, sensitive or resistant, by median concentration of LD70 or LCS. When patients were classified into three groups by sensitivity to four drugs of DPAV (dexamethasone, prednisolone, L-asparaginase, and vincristine), 3-year event-free survival (EFS; 95% confidence intervals) of the super sensitive group (SS; sensitive to all 4 drugs) was 0.833 (0.690 to 0.976), that of the intermediate sensitive group (IS; sensitive to 2 or 3 drugs) was 0.735 (0.609 to 0.863), and that of the relatively resistant group (RR; sensitive to no drugs or to 1 drug) was 0.541 (0.411 to 0.670; P = .0008). We then investigated the relationship between the above four-drug sensitivity and the time of relapse. The SS and IS patients tended to maintain continuous complete remission, and RR patients tended to undergo induction failure and early and late relapse (P = .004). Initial white blood cell count, immunologic classification, and age were also predictive factors, but the patient numbers showed no statistical correlation between these factors and the four-drug sensitivity groups (SS, IS, and RR). When we took three groups SS/IS/RR and investigated the EFS for various clinical groups, DPAV sensitivity strongly influenced EFS in the standard-risk ALL (P = .016). In vitro drug sensitivity testing provides additional prognostic information about childhood ALL, and early detection of drug resistance at the time chemotherapy commences may provide a successful strategy for individualizing treatment, as the results indicate de novo resistance to front-line drugs and suggest alternative, second-line drugs.
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PMID:In vitro drug sensitivity testing can predict induction failure and early relapse of childhood acute lymphoblastic leukemia. 910 16

Eighteen patients (men=14; women=4) with natural killer (NK)/T-cell lymphomas (CR1, N=9; CR2, N=7; PR, N=1; progressive disease, N=1) undergoing allogeneic haematopoietic SCT (HSCT) (myeloablative, N=14; reduced intensity, N=4) were analyzed. With a median follow-up of 20.5 months, the 5-year OS was 57% and 5-year EFS was 51%. The use of the SMILE regimen pre-HSCT was the most important positive prognostic indicator, resulting in significantly superior OS and EFS (P<0.01). Acute GVHD had a significant negative impact on OS (P=0.03). CR1 and CR2 patients had similar survivals, but all patients who were not transplanted in remission died. Chronic GVHD, International Prognostic Index, disease stage, primary sites of involvement, conditioning regimen and source of HSC did not affect survival. Although allogeneic HSCT leads to reasonable survival for NK/T-cell lymphoma patients, results need to be compared with those in patients receiving L-asparaginase-containing regimens. Novel prognostic models incorporating biomarkers, such as circulating EBV DNA, are needed to identify high-risk patients who may benefit from allogeneic HSCT.
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PMID:Allogeneic haematopoietic SCT for natural killer/T-cell lymphoma: a multicentre analysis from the Asia Lymphoma Study Group. 2477 95