David R. Head

Revised Recommendations of the International Working Group for Diagnosis, Standardization of Response Criteria, Treatment Outcomes, and Reporting Standards for Therapeutic Trials in Acute Myeloid Leukemia

An International Working Group met to revise the diagnostic and response criteria for acute myelogenous leukemia originally published in 1990, as well as to provide definitions of outcomes and reporting standards to improve interpretability of data and comparisons among trials. Since the original publication, there have been major advances in our understanding of the biology and molecular genetics of acute leukemia that are clinically relevant and warrant incorporation into response definitions. Differences from the 1990 recommendations included a category of leukemia-free state, new criteria for complete remission, including cytogenetic and molecular remissions and remission duration. Storage of viable blasts for correlative studies is important for future progress in the therapy of these disorders.

Report of the National Cancer Institute-sponsored workshop on definitions of diagnosis and response in acute myeloid leukemia.

The National Cancer Institute (NCI) sponsored a workshop to develop a set of standardized diagnostic and response criteria for acute myeloid leukemia (AML) clinical trials. The French-American-British (FAB) classification was retained for diagnosing AML, with the addition of patients with bone marrow morphologic features of a myelodysplastic syndrome and less than 30% bone marrow blasts, but with greater than or equal to 30% blasts in the peripheral blood. In this report, there are four important subgroups of AML not defined in the FAB classification that are discussed: undifferentiated acute leukemia, MO (AML lacking definitive myeloid differentiation by morphology or conventional cytochemistry but with ultrastructural or immunophenotypic evidence for AML), mixed lineage leukemia, and hypocellular AML. Definitions of response for clinical trials are presented to facilitate comparisons among different studies. Complete remission is considered the only response worth reporting in phase III trials, since lesser responses do not improve survival. Partial remissions may be of interest to identify active new agents in phase I and II studies. Monoclonal antibodies and cytogenetic studies are not part of the routine assessment of remission or reassessment at relapse, and their role in the evaluation of patients with AML is currently being evaluated in clinical trials. Although we recognize that some of the definitions in this report are arbitrary, generalized use of these guidelines will make results of clinical trials more comparable and interpretable.

Acute Myeloid Leukemia in Children Treated with Epipodophyllotoxins for Acute Lymphoblastic Leukemia

BACKGROUND AND METHODS Treatment of cancer with the epipodophyllotoxins (etoposide and teniposide) has been linked to the development of acute myeloid leukemia (AML) in children and adults, but the factors that might influence the risk of this complication of therapy are poorly defined. We therefore assessed the importance of potential risk factors for secondary AML in 734 consecutive children with acute lymphoblastic leukemia who attained complete remission and received continuation (maintenance) treatment according to different schedules of epipodophyllotoxin administration. RESULTS Secondary AML was diagnosed in 21 of the 734 patients, in 17 of whom this complication was the initial adverse event. Prolonged administration of epipodophyllotoxin (teniposide with or without etoposide) twice weekly or weekly was independently associated with the development of secondary AML (P less than 0.01 by Cox regression analysis). The overall cumulative risk of AML at six years was 3.8 percent (95 percent confidence interval, 2.3 percent to 6.1 percent); but within the subgroups treated twice weekly or weekly, the risks were 12.3 percent (95 percent confidence interval, 5.7 percent to 25.4 percent) and 12.4 percent (95 percent confidence interval, 6.1 percent to 24.4 percent), respectively. In the subgroups not treated with epipodophyllotoxins or treated with them only during remission induction or every two weeks during continuation treatment, the highest cumulative risk was 1.6 percent (95 percent confidence interval, 0.4 percent to 6.1 percent). After adjustment for treatment frequency, there was no apparent relation between the total dose of epipodophyllotoxins and the development of secondary AML. The relative hazard of etoposide as compared with teniposide could not be determined. CONCLUSIONS The risk of epipodophyllotoxin-related AML depends largely on the schedule of drug administration. Other factors, including the cumulative dose of epipodophyllotoxin, radiotherapy, and the initial biologic features of the leukemic blast cells, do not appear to have critical roles.

Chemotherapy Compared with Autologous or Allogeneic Bone Marrow Transplantation in the Management of Acute Myeloid Leukemia in First Remission

BACKGROUND In young adults with acute myeloid leukemia, intensive chemotherapy during the initial remission improves the long-term outcome, but the role of bone marrow transplantation is uncertain. We compared high-dose cytarabine with autologous or allogeneic marrow transplantation during the first remission of acute myeloid leukemia. METHODS Previously untreated adolescents and adults 16 to 55 years of age who had acute myeloid leukemia received standard induction chemotherapy. After complete remission had been achieved, idarubicin (two days) and cytarabine (five days) were administered. Patients with histocompatible siblings were offered allogeneic marrow transplantation, whereas the remaining patients were randomly assigned to receive a single course of high-dose cytarabine or transplantation of autologous marrow treated with perfosfamide (4-hydroperoxycyclophosphamide). Oral busulfan and intravenous cyclophosphamide were used as preparative regimens for both allogeneic and autologous marrow transplantation. The end points were survival from the time of complete remission and disease-free survival. RESULTS In an intention-to-treat analysis, we found no significant differences in disease-free survival among patients receiving high-dose chemotherapy, those undergoing autologous bone marrow transplantation, and those undergoing allogeneic marrow transplantation. The median follow-up was four years. Survival after complete remission was somewhat better after chemotherapy than after autologous marrow transplantation (P=0.05). There was a marginal advantage in terms of overall survival with chemotherapy as compared with allogeneic marrow transplantation (P=0.04). CONCLUSIONS A postinduction course of high-dose cytarabine can provide equivalent disease-free survival and somewhat better overall survival than autologous marrow transplantation in adults with acute myeloid leukemia.

A pediatric approach to the WHO classification of myelodysplastic and myeloproliferative diseases.

Myelodysplastic and myeloproliferative disorders are rare in childhood and there is no widely accepted system for their diagnosis and classification. We propose minimal diagnostic criteria and a simple classification scheme which, while based on accepted morphological features and conforming with the recent suggestions of the WHO, allows for the special problems of myelodysplastic diseases in children. The classification recognizes three major diagnostic groups: (1) juvenile myelomonocytic leukemia (JMML), previously named chronic myelomonocytic leukemia (CMML) or juvenile chronic myeloid leukemia (JCML); (2) myeloid leukemia of Down syndrome, a disease with distinct clinical and biological features, encompassing both MDS and AML occurring in Down syndrome; and (3) MDS occurring both de novo and as a complication of previous therapy or pre-existing bone marrow disorder (secondary MDS). The main subtypes of MDS are refractory cytopenia (RC) and refractory anemia with excess of blasts (RAEB). It is suggested retaining the subtype of RAEB-T with 20–30% blasts in the marrow until more data are available. Cytogenetics and serial assessments of the patients are essential adjuncts to morphology both in diagnosis and classification.

Randomized comparison of pentostatin versus interferon alfa-2a in previously untreated patients with hairy cell leukemia: an intergroup study.

PURPOSE Therapy of hairy cell leukemia has markedly improved. Interferon alfa-2a and pentostatin are active agents. The National Cancer Institute organized an intergroup trial to compare these agents prospectively in untreated patients. METHODS Patients were randomized to receive either interferon alfa-2a (3 x 10(6) U subcutaneously three times per week) or pentostatin (4 mg/m2 intravenously every 2 weeks). Patients who did not respond to initial treatment were crossed over. RESULTS Of 356 patients on study, 313 were eligible. Among interferon patients, 17 of 159 (11%) achieved a confirmed complete remission and 60 of 159 (38%) had a confirmed complete or partial remission. Among pentostatin patients, 117 of 154 (76%) achieved a confirmed complete remission and 121 of 154 (79%) had a confirmed complete or partial remission. Additional patients achieved criteria for complete remission, but lacked confirmatory follow-up evaluation. Response rates were significantly higher (P < .0001) and relapse-free survival was significantly longer with pentostatin than interferon (P < .0001). The median follow-up duration is 57 months (range, 19 to 82). Myelosuppression was more frequent with pentostatin (P = .013). A multivariate logistic regression analysis of the confirmed complete remissions on pentostatin showed the following factors to be important for achieving a complete remission: high hemoglobin level (two-tailed P = .024), young age (P = .0085), and no or little splenomegaly (P = .0029). CONCLUSION Both agents were well tolerated. Pentostatin produced higher response rates, and the responses were durable. Patient age and clinical status had an impact on outcome with pentostatin. Pentostatin is effective therapy for hairy cell leukemia.

TEL gene rearrangement in acute lymphoblastic leukemia: a new genetic marker with prognostic significance.

PURPOSE TEL gene rearrangements due to the 12;21 chromosomal translocation are the most common molecular genetic abnormality in childhood acute lymphoblastic leukemia (ALL), occurring in approximately 25% of cases with a B-precursor immunophenotype. The limited number of clinically useful genetic markers in this leukemia subtype prompted us to assess TEL status as a predictor of treatment outcome. PATIENTS AND METHODS We determined the status of the TEL gene (rearranged or germline) in 188 cases of B-precursor acute leukemia using Southern blot analysis and related the findings to event-free survival. All comparisons of outcome were stratified by treatment regimen, risk classification, age, and leukocyte count. RESULTS Forty-eight patients (26%) had a rearranged TEL gene. At 5 years of follow-up, an estimated 91% +/- 5% (SE) of this group were event-free survivors, compared with only 65% +/- 5% of the group with germline TEL (stratified log-rank P = .011). For nonhyperdiploid patients, the odds ratio of an adverse event in the germline TEL group to that for the rearranged TEL group was 4.06 (95% confidence interval, 1.86 to 8.84). The relationship of TEL rearrangement to a favorable prognosis was independent of recognized good-risk features in B-precursor leukemia, including age, initial leukocyte count, and hyperdiploidy. CONCLUSION Rearrangement of the TEL gene distinguishes a large subset of children with favorable-prognosis B-precursor leukemia who cannot be identified by standard prognostic features. It may be possible to treat these patients less aggressively without loss of therapeutic efficacy.

11q23/MLL rearrangement confers a poor prognosis in infants with acute lymphoblastic leukemia.

PURPOSE Leukemic cell characteristics were analyzed in infants less than 1 year of age with acute lymphoblastic leukemia (ALL) to determine adverse prognostic factors that might explain the poor prognosis of this group. PATIENTS AND METHODS Treatment outcomes were analyzed according to the presenting clinical and laboratory features of 30 infants treated between May 1979 and April 1993. A stepwise multivariate regression model was used to identify the most important prognostic indicator with respect to event-free survival. RESULTS Infant ALL cases were characterized by high presenting leukocyte count (median, 87 x 10(9)/L), increased frequency of CNS leukemia (50%), and blast cells with a CD10- phenotype (67%), myeloid-associated antigen expression (48%), and 11q23/MLL rearrangement (68%). The 11q23/MLL involvement was correlated with age less than 6 months, CD10- phenotype, myeloid-associated antigen expression, and high leukocyte count. Although 11q23/MLL involvement, age less than 6 months, myeloid-associated antigen expression, and female sex were each significantly associated with an inferior treatment outcome, only rearranged 11q23/MLL emerged as an independent predictor of prognosis in multivariate analysis (P = .01). Infants with this genetic abnormality had a 4.7-fold (95% confidence interval, 1.3- to 17.0-fold) increased risk in adverse events compared to other infants. CONCLUSION The 11q23/MLL involvement of blast cells identifies a major subgroup of infant ALL cases that require an innovative treatment approach. Infants who lack this genetic abnormality have an intermediate prognosis and could be treated accordingly on risk-directed protocols.

Improved survival for children with B-cell acute lymphoblastic leukemia and stage IV small noncleaved-cell lymphoma: a pediatric oncology group study.

PURPOSE In an effort to improve outcome for children with advanced B-cell malignancies, a treatment plan based on a published regimen that consists of four courses of fractionated cyclophosphamide (cyclo) given with doxorubicin (doxo) and vincristine (VCR) was intensified by alternating with sequential high-dose methotrexate (MTX) and cytarabine (Ara-C), given in conjunction with intrathecal (IT) MTX and Ara-C. PATIENTS AND METHODS From October 1986 to October 1992, 133 eligible patients were enrolled: 74 with B-cell (surface immunoglobulin-positive [Slg+] acute lymphoblastic leukemia (B-ALL) and 59 with stage IV small noncleaved-cell lymphoma (SNCCL). The median age was 8 years; there were 103 males and 30 females. Abdominal tumor masses were prominent in 63 cases (33 B-ALL and 30 stage IV SNCCL). RESULTS Complete remission (CR) was achieved in 66 B-ALL and 57 stage IV patients (93% overall). At 4 years, the estimated event-free survival (EFS) rate is 65% +/- 8% for patients with B-ALL and 79% +/- 9% for those with stage IV SNCCL. Among patients with CNS involvement, 23 of 36 remain in CR (4-year EFS rate, 64% +/- 13%). Relapses occurred early; only 3 patients relapsed after completion of therapy. Thirteen relapses occurred in the marrow, three in the CNS, and six in other sites. Of 11 CNS-positive patients who relapsed, only two recurred primarily in the CNS. CONCLUSION The results of this study indicate that with intensified chemotherapy an increasing potential for cure exists for patients with B-ALL and stage IV SNCCL.

11q23 balanced chromosome aberrations in treatment-related myelodysplastic syndromes and acute leukemia: Report from an International Workshop†

Among 511 patients with therapy‐related myelodysplastic syndrome or acute leukemia (t‐MDS/t‐AL) and balanced chromosome aberrations, 162 (32%) had translocations involving 11q23. The recurring translocation partners were 9p22 (48%), 19p13.3 (11%), 19p13.1 (10%), 4q21 (9%), 6q27 (6%), 1p32 (2%), 16p13.1 (2%), 10p13 (1%), and 17q25 (1%); in 9%, the translocations were seen only once. The remaining 349 patients were divided into five subgroups based on the balanced aberration: 21q22, inv(16), t(15;17), Rare, and Unique aberrations. Patients in the 11q23 subgroup had a sole cytogenetic abnormality more often than those in the 21q22, inv(16), Rare, and Unique subgroups, and a complex karyotype or −5/del(5q) and/or −7/del(7q) less often than patients in the 21q22, Rare, and Unique subgroups. Clinically, 11q23 patients had acute lymphoblastic leukemia (ALL) more often as their primary disease and a shorter latency from start of treatment for the primary disease to their t‐MDS/t‐AL diagnosis, except when compared with the inv(16) subgroup. The 11q23 subgroup demonstrated a younger age at t‐MDS/t‐AL diagnosis, but this finding was not significant when patients with AL as their primary diagnosis were excluded. Survival from the time of diagnosis of t‐MDS/t‐AL was significantly shorter for the 11q23 subgroup compared with that of the 21q22, inv(16), and t(15;17) subgroups (median 8 vs. 14, 28, and 29 months, respectively). Inferior survival occurred even though 11q23 patients were younger and more often received blood or marrow transplantation (BMT). Even among patients receiving BMT, 11q23 patients had a shorter median survival (9 vs. 12–31 months for the other subgroups). However, among 11q23 patients, those receiving BMT survived longer, with 1‐ and 5‐year survivals of 43% and 18% compared with 23% and 7% for patients not transplanted. With regard to prior therapy, 11q23 patients, compared with other patients, received radiotherapy less often as their sole therapy and chemotherapy more often. They had received VP16, methotrexate, 6MP/6TG, L‐asparaginase, daunorubicin, cytarabine, and VM26 more often, likely attributed to the high frequency of AL as their primary disease. More patients in the 11q23 subgroup had received doxorubicin, except in comparison with the 21q22 subgroup; more vincristine, except in comparison with the Rare and Unique subgroups; and more prednisone, except in comparison with the Unique subgroup. Patients in the 11q23 subgroup more often received alkylating agents (AAs) (86% vs. 59–82% for the other subgroups), and topoisomerase II inhibitors (TIs) (84% vs. 49–75%), and they more often reported exposure to AAs plus TIs without radiotherapy (33% vs. 12–21%), except in comparison with the 21q22 subgroup (36%). We performed a multivariate analysis to determine whether the adverse survival of 11q23 patients compared to other Workshop patients was explained by factors other than the presence of the 11q23 abnormality. Covariates in the final model were the five cytogenetic subgroup indicators, where the 11q23 subgroup was the referent (P < 0.0001); age at t‐MDS/t‐AL (P = 0.0036); previous exposure to lomustine (P < 0.0001) and mitoxantrone (P = 0.0225); BMT for t‐MDS/t‐AL (P = 0.0006); and karyotype complexity (P = 0.0114). The risk of death for 11q23 patients relative to patients in the 21q22, inv(16), t(15;17), and Unique subgroups was significant, even after adjustment for other risk factors (relative risks 2.3, 3.6, 3.1, and 1.5, respectively; P < 0.0001 for the first three comparisons and P = 0.0125 for the last). When a multivariable model was constructed, excluding patients with AL or MDS as their primary diagnosis, the relative risk of death for 11q23 patients was significantly higher than that of all five other cytogenetic subgroups. We conclude that among t‐MDS/t‐AL patients with balanced aberrations, 11q23 translocations are an independent adverse risk factor. Although BMT is the current therapy of choice, new treatment is required.