CD Bloomfield

In a randomized study of acute myelocytic leukemia (AML), 352 patients of all ages were treated for remission induction by one of the four regimens: 7 days of cytosine arabinoside (ara-C) by continuous intravenous (i.v.) infusion or bolus injection every 12 hr, together with daunorubicin (DNR) by rapid i.v. injection on days 1, 2, 3; or 5 days of ara-C by infusion or bolus injection and DNR for 2 days only. The regimen of 7 and 3 infusion was significantly superior to the other 3 regimens, resulting in 56% complete remission (CR). For remission maintenance, ara-C was given for 5 days every month and each month one of the following four drugs added on a cyclic rotational basis: thioguanine, cyclophosphamide, CCNU, or DNR. Although ara-C dosage each month was the same, the route of ara-C administration by random allocation was either rapid i.v. bolus or subcutaneous (s.c.) injection. The median duration of CR was significantly longer for s.c. ara-C group: 14 mo for patients less than 60 yr old (versus 8 mo for i.v.) and 31 mo for 60 or older age group (versus 9 mo for i.v.). Patients who received a combination of the best of the four induction regimens (7 and 3 infusion) and the better of the two maintenance schedules (s.c. ara-C) had a median remission duration of 22 mo and a median survival of 35 mo (the longest reported in a prospective randomized trial of therapy for AML). These results establish the validity of an intensive chemotherapy to produce rapid marrow aplasia followed by a sequential maintenance therapy for achieving prolonged disease-free survival in AML.

The importance of banded chromosome analyses in predicting long-term outcome in acute lymphoblastic leukemia (ALL) was evaluated in this follow-up study of 329 patients from the Third International Workshop on Chromosomes in Leukemia. Patients were divided into ten groups according to pretreatment karyotype: no abnormalities, one of the following structural abnormalities [the Philadelphia chromosome, translocations involving 8q24,t(4;11), 14q+, 6q-] or, in the remaining cases, modal number [less than 46, 46, 47 to 50, greater than 50]. Achievement and duration of complete remission (CR) and survival differed among chromosome groups (P less than .0001). Karyotype was an independent prognostic factor for duration of first CR and survival, even when age, initial leukocyte count (WBC), French-American-British (FAB) type, and immunologic phenotype were considered. Among adults, prolonged remission and survival were uncommon in all chromosome groups. Only in the normal karyotype group was median survival even two years. Among children, striking differences in long-term remission and survival were seen depending upon karyotype. Children in the greater than 50 group did best, with 70% remaining in first CR for a median duration in excess of five years. Children in the 47-50, 6q-, and normal karyotype groups also had prolonged survivals. In contrast, certain translocations [t(9;22)(q34;q11), t(4;11)(q21;q14-23), t(8;14)(q24;q32)] identified children who had short survivals, even in the presence of favorable prognostic factors including a low WBC, L1 morphology, and non-T, non-B immunologic phenotype. We conclude that chromosome analysis is required at diagnosis in patients with ALL, and that children with these specific translocations should be managed as having high-risk ALL.

The Philadelphia (Ph1) chromosome, or its molecular counterpart, the BCR-ABL fusion gene, is a rare but important prognostic indicator in childhood acute lymphoblastic leukemia (ALL), but its impact on adult ALL has not been well ascertained. A prospective study of the BCR-ABL fusion gene was begun on patients entered on clinical trials conducted by the Cancer and Leukemia Group B (CALGB). All patients received intensive, multiagent chemotherapy that included daunorubicin. Over 2 years, 56 patients were studied for molecular evidence of a BCR-ABL gene using Southern blot and pulsed-field gel hybridization analysis. Results were compared with cytogenetic detection of a Ph1 chromosome, and clinical features were compared for the BCR-ABL-positive and -negative groups. Molecular methods detected the BCR-ABL gene in 30% of cases compared with cytogenetic detection of the Ph1 chromosome in only 23%. The majority of cases (76%) showed the p190 gene subtype similar to pediatric ALL; the BCR-ABL-positive cases displayed a more homogeneous immunophenotype than the BCR-ABL-negative cases and were predominantly CALLA positive (86%) and B-cell surface antigen positive (82%). The rate of achieving complete remission was similar in the BCR-ABL-positive and -negative groups (71% and 77%, respectively, P = .72). There were more early relapses in the BCR-ABL-positive group, resulting in a shorter remission duration that was especially marked in the CALLA-positive and B-cell antigen-positive populations. These preliminary data suggest that the impact of the BCR-ABL gene on clinical outcome in ALL may be on maintenance of complete remission (CR) rather than achievement of CR when aggressive, multiagent chemotherapy is used. This study identifies the BCR-ABL gene as an important factor in adult ALL and demonstrates the utility of molecular methods for its accurate diagnosis.

Recently, several specific chromosomal abnormalities have been associated with distinctive clinical and/or morphological subtypes of acute nonlymphocytic leukemia (ANLL). To further investigate the clinical utility of karyotype analysis in ANLL, we have examined G-banded metaphase chromosomes at diagnosis in 61 consecutive patients. Of the 60 patients who had adequate mitoses, 47 (78%) had a clonal chromosome abnormality. The sole karyotypic abnormality found in 5 patients was a del(16)(q22). The unique pretreatment characteristic of these 5 patients was marrow eosinophilia ranging from 8% to 54%. No other patient had more than 4% marrow eosinophils. Among the patients with eosinophilia, all had Auer rods, serum muramidase was elevated in the 4 tested, and 4 had hepatomegaly at presentation. Both patients who survived initial treatment remain in complete remission at 23+ and 33+ mo. The data suggest that we have identified a new cytogenetic-clinical subtype of ANLL defined by the del(16)(q22).