Increased survival in childhood acute nonlymphocytic leukemia after treatment with prednisone, cytosine arabinoside, 6-thioguanine, cyclophosphamide, and oncovin (PATCO) combination chemotherapy

Lessons from the past: opportunities to improve childhood cancer survivor care through outcomes investigations of historical therapeutic approaches for pediatric hematological malignancies

Investigations of long-term outcomes have been instrumental in designing safer and more effective contemporary therapies for pediatric hematological malignancies. Despite the significant therapeutic changes that have occurred over the last five decades, therapy modifications largely represent refinements of treatment protocols using agents and modalities that have been available for more than 30 years. This review summarizes major trends in the evolution of treatment of pediatric hematological malignancies since 1960 to support the relevance of the study of late effects of historical therapeutic approaches to the design and evaluation of contemporary treatment protocols and the follow-up of present-day survivors.

Gonadal Function in Patients Treated for Leukemia in Childhood

Ovarian and testicular function were assessed in 67 long-term survivors (37 females, 30 males) treated for leukemia between 1973 and 1992. At diagnosis they were 1-16 (median 5) years old and had evaluation of gonadal function 4-25 (median 13) years later at the age of 13-31 (median 19). All had been treated with various combinations of chemotherapy (ChT) (including cyclophosphamide (CYC) and cytarabine in 32 patients), 62 patients had received prophylactic cranial irradiation with 12-49 (median 18) Gy, 2 patients had had craniospinal irradiation with 24 and 10 Gy respectively. Nine patients were treated for relapse; 2 boys had testicular irradiation (RT) with 12 Gy in 3 fractions and 1 girl whole-abdomen RT with 20 Gy as a part of this treatment. Three patients were treated for second malignancies. Gonadal function was assessed by clinical examination and measurement of serum concentrations of estradiol and testosterone. Serum levels of LH and FSH were determined in basal state and after stimulation. Primary hypogonadism was found in 6 (9%) patients. Five (16,5%) males had primary hypogonadism with evidence of damage to the germinal epithelium, 2 of them, treated with testicular RT, had evidence of damage to the Leydig cells and 2 had evidence of dysfunction of Leydig cells as well. Primary hypogonadism was found in 1 female, who was heavily treated for relapse (ChT containing CYC, abdominal RT and craniospinal RT). She was amenorrhoic and needed substitutional estrogen therapy but delivered a child anyway. Five females had early puberty after cranial RT. One female had secondary hypogonadism and hyposomatotropism after cranial RT with 30 Gy, one male had hyposomatotropism after receiving cranial RT twice (49 Gy total). Primary treatment for leukemia does not produce primary hypogonadism in girls, but it does in boys. Alkylating agents and gonadal RT are the most damaging factors. Not only RT to gonads but also alkylating agents alone cause dysfunction of Leydig cells.

Treatment strategies for pediatric acute myeloid leukemia

Therapeutic strategies utilized in recently completed Phase III clinical trials in children with de novo acute myeloid leukemia have led to long-term disease-free survival in 50 - 60% of children. This review describes the contributions from early intensification of therapy and postremission intensification using highly myelosuppressive chemotherapy strategies and discusses the controversial roles of allogeneic bone marrow transplantation, maintenance therapy and CNS irradiation. Current strategies focusing on the identification of critical biologic features and measurements of early response to therapy allow for greatly improved risk group stratification. Future improvements in the treatment of children with acute myeloid leukemia will depend on a better understanding of the biology of the disease, targeted therapeutic approaches directed to specific biologic targets, selective use of allogeneic transplantation and innovative clinical trial designs that will allow for the testing of an increasing number of new agents in increasingly small numbers of patients in defined risk groups.

Curing childhood acute myeloid leukemia (AML) at the half-way point: promises to keep and miles to go before we sleep

Childhood and adolescent acute myeloid leukemia (AML) is traditionally one of the hardest childhood cancers to successfully treat and had an overall survival well under 10% in the 1960s. Initial progress was made by three major events: (1) active chemotherapeutic agents were identified which led to remissions for the first time in this disease; (2) cooperative groups were instituted leading to important clinical trials; and (3) several single institutions began experimenting with the role of allogeneic matched sibling donor (MSD) BMT as effective intensification. Over the last 25 years, the cure rate has improved from <20% to 50% or higher. Most of the clinical research during this time of great advancement focused on two major themes: (1) the role of aggressive induction therapy in not only improving CR rates but in post-remission outcomes; and (2) the role of aggressive post-remission therapy in further improving survival, with an emphasis on high-dose Ara C-based chemotherapy, BMT, and supportive care. But we have "miles to go before we sleep." Some of the challenges that will lead to ongoing reduction of population-based mortality for AML through young adulthood include: (1) improving access of adolescents to pediatric AML therapy; (2) stratification by prognostic factors; (3) individualized therapy based on individual genetics and leukemia cell biology; (4) and the use of novel therapies including targeted immuno-conjugates and "small molecules" which disrupt abnormal signal transduction pathways. This brief review looks at both the advances over the last three decades as well as discusses the challenges moving forward for ultimately curing all children with this disease.

Long-term results of children with acute myeloid leukemia: a report of three consecutive Phase III trials by the Children's Cancer Group: CCG 251, CCG 213 and CCG 2891

The Children's Cancer Group (CCG) conducted three Phase III prospective clinical trials for children with de novo acute myeloid leukemia between the years 1979 and 1995. A total of 1903 eligible children ages birth to 21 years of age were enrolled on CCG 251 (n=485), CCG 213 (n=532) and CCG 2891 (n=886). Follow-up is ongoing, with medians of 7.9, 10.9 and 8.6 years, respectively. These three clinical trials developed dose- and time-intensive induction regimens based upon high-dose cytarabine and daunomycin and randomly assigned patients to allogeneic bone marrow transplantation in first remission if an HLA-matched related donor was identified. Despite dose- and time-intensive induction regimens, remission induction rates remained relatively stable at 77-78%. However, overall survival, event-free survival and disease-free survival (DFS) increased for patients receiving intensive-timing induction therapy in comparison to patients who received standard-timing induction, regardless of the type of postremission therapy. Outcomes were best for patients receiving intensive-timing induction followed by matched related donor allogeneic transplantation with DFS of 65+/-9% at 6 years. These three clinical trials have established a strong foundation for the development of future studies focusing on further risk group stratification and the development of novel, molecularly-targeted therapies.

Improvement in outcome for children with acute nonlymphocytic leukemia. A report from the Childrens Cancer Study Group

The Childrens Cancer Study Group conducted four therapeutic studies on a total of 1006 children with acute nonlymphocytic leukemia from 1972 to 1983. This report describes the therapeutic strategies of these studies and examines trends in induction rates and long-term outcome over this period. The remission induction rate has changed from 58% in 1972 to 1975 to 80% for the period 1980 to 1983, and the induction mortality dropped from 20% to 6%. Four-year survival probabilities from time of diagnosis have almost doubled from 19% to 36%. Few deaths occurred more than 5 years after diagnosis: children surviving in first remission beyond 5 years had a 92% survival rate and an 86% relapse-free survival rate over the next 5 years. In contrast, median survival after a marrow relapse was less than 6 months and the 6-year survival probability was 4%. The leukocyte count was a significant prognostic factor, and although the mortality for infants was high initially, long-term survival was not decreased.

Long-term results in the treatment of acute nonlymphocytic leukemia: a Pediatric Oncology Group Study

Complete remission (CR), 5-year remission duration (RD), and overall 5-year survival rates are 74%, 28% and 25%, respectively, for previously untreated children with acute nonlymphocytic leukemia diagnosed between 1977 and 1981, following induction therapy with vincristine, doxorubicin and prednisone (VAP), consolidation therapy with 6-thioguanine, cytosine arabinoside (TA) and cyclophosphamide/vincristine/cytosine arabinoside/prednisone (COAP), and maintenance therapy of alternating TA and COAP with or without VAP pulses. Approximately 20% are free of their disease for more than 5 years. High white blood cell counts (WBC) at diagnosis and M3 and M6 morphology were associated with lower CR rates, while M5 morphology was associated with higher CR rates. Patients with M1 morphology had shorter remission duration as compared to those with M4 or M5 morphology. Low WBC and age between 2 and 10 years at diagnosis were associated with longer remission durations and survival. Patients with M4 morphology also survived longer. The observed CR rates are comparable to other studies initiated at the same time as this study but survival is less than those reported more recently. Low WBC at diagnosis and M4/M5 morphology may identify relatively favorable prognostic groups.

Remission induction in children with acute non-lymphocytic leukemia using cytosine arabinoside and doxorubicin or daunorubicin: a report from the Childrens Cancer Study Group

Four hundred ninety evaluable patients were treated on an induction regimen consisting of two to four courses of cytosine arabinoside plus an anthracycline. Overall, 78% of patients went into remission, 10% died during induction, and 12% were induction failures. For the first 152 patients, courses consisted of 7 days continuous infusion with cytosine arabinoside (Ara-C, 100 mg/m2) and 3 days of doxorubicin (30 mg/m2). Because of unacceptable toxicity, particularly for children less than 3 years of age, the anthracycline was changed to daunorubicin, and the doses of both induction drugs for children under 3 was reduced. For children aged 3 years and older the change in anthracycline was associated with a significant increase in induction failures (7% to 16%, P = .04) and a decrease in deaths (15% to 8%, P = .09). For younger children, for whom doses were also changed, the effect was greater; Mortality decreased from 29% to 1% (P less than .0001), and the remission induction rate increased from 66% to 88% (P = .005). The therapy modifications also influenced survival following remission induction: Daunorubicin-treated patients, aged 3 years and over, did significantly better than those given doxorubicin (P = .03), but the opposite was seen in younger children (P = .06). Gastrointestinal and skin toxicities and septicemia were significantly more common when doxorubicin was being used, but the extent of myelosuppression was similar for the two anthracyclines.

Biologic characteristics and treatment of acute nonlymphocytic leukemia in children. Report of the ANLL Strategy Group of the Childrens Cancer Study Group

Today approximately 75 per cent of children with ANLL can be induced into a complete remission and approximately 40 per cent will have an event-free survival for more than 3 years, irrespective of whether they received a bone marrow transplantation or chemotherapy after induction. In order to achieve these results very intensive therapy is required. The morbidity and mortality of treatment are high. The length of therapy needed after induction of remission is not known. Whether or not maintenance therapy is required is perhaps related most directly to the intensity of the therapy employed. Similarly, the role of bone marrow transplantation in patients in first remission, treatment of CNS leukemia, and treatment of chloromas are controversial. There is general agreement that WBCs over 100,000, acute monoblastic leukemia in infants less than 2 years of age, and certain chromosomal abnormalities are associated with a poor prognosis. Although there has been a dramatic improvement in the treatment of ANLL over the past 15 years, stratification of therapy based on biologic parameters, and alteration of treatment based on the early responses to treatment may be required before further advances will be made.

Biology and therapy of childhood acute nonlymphocytic leukemia

Childhood nonlymphocytic leukemia comprises a minority (25%) of pediatric leukemia cases, yet contributes a significant proportion of overall leukemia mortality. Improvements in supportive care (antibiotics, antifungals, nutrition, and blood products) along with aggressive induction therapies have significantly improved remission induction rates over the past two decades. Ideal treatment to completely eliminate residual disease following remission is not yet known. In most series, only one out of three patients are long-term survivors of this disease. Recent advances in allogeneic bone marrow transplantation and improved techniques for autologous engraftment leave promise for significant improvements in postinduction disease control. Biologic studies of surface immunophenotype have contributed to our understanding of the heterogeneity of this family of disorders and allowed identification and characterization of leukemias of mixed myeloid/lymphoid lineage. Karyotype studies have identified important subsets of ANLL with distinctive clinical and biologic properties, for which tailored therapies someday may be developed. In addition, studies of oncogenes provide insight into regulation of leukemic hematopoiesis with potential of identifying future methods to regulate proliferation of the leukemic clone.

Bone-marrow transplantation for haematological malignancy in childhood

Twenty-three children with haematological malignancies and a poor prognosis underwent bone-marrow transplantation. Thirteen children had acute lymphoblastic leukaemia, eight had acute nonlymphoblastic leukaemia, one had chronic myeloid leukaemia and one had malignant histiocytosis. One child was in relapse at the time of transplant and 22 were in first or subsequent remission. Before transplantation all patients received cyclophosphamide (60 mg/kg) on two consecutive days followed by total body irradiation given as a single dose of 10 Gy at 0.18 Gy/min (one patient) or 0.07 Gy/min (three patients), or as a fractionated dose of 10-12 Gy at 0.07-0.1 Gy/min (19 patients). One child with malignant histiocytosis also received two doses of etoposide (5 mg/kg). Methotrexate was given after transplantation to prevent or modify graft-versus-host disease (GVHD). One patient who received a transplant in relapse died early from overwhelming bacterial sepsis. Twenty-two patients engrafted, and of these 11 developed acute GVHD; five developed chronic GVHD; seven developed interstitial pneumonitis, with four deaths; and five relapsed between three and 12 months after transplantation, with three deaths. Fifty-nine per cent (13/22) of patients who received a transplant during remission remain in continuous complete remission and 68% (15/22) have survived for a median of 18 months (range, four to 73 months). Bone-marrow transplantation that is undertaken during remission of disease offers a prolonged disease-free survival in selected childhood malignancies.

Current status of treatment of acute leukemia in adults: an overview of the Memorial experience and review of literature

The results of treatment of 629 previously untreated adults with acute leukemia at Memorial Hospital are reviewed. During the past 14 years, 135 adults (greater than 15 years) with acute lymphoblastic leukemia (ALL) have been treated with one of three successive multidrug-intensive treatment protocols (L2, L10/10M, and L17/17M), each calling for 2.5 to 3 years of systemic chemotherapy and prophylactic intrathecal methotrexate without cranial irradiation. The complete remission (CR) rates were L2 (n = 22) = 77%; L10/10M (n = 69) = 86%; L17/17M (n = 44) = 77%. The median durations of survival and remission were, respectively, L2 = 33 and 30 months; L10/10M = 62 months and not reached; and L17/17M = not reached. Almost all relapses occurred within the first 3 years while still continuing treatment, and there were only rate late relapses after stopping treatment. It appears that approximately half of the patients may have been cured with the latest two protocols. During the last 17 years, 494 adults aged 15 to greater than 70 with acute nonlymphoblastic leukemia (ANLL) were treated with one of five successive multiple drug treatment protocols of varying intensity (arabinosylcytosine + 6-thioguanine [n = 36]; L6 [n = 101]; L12 [n = 104]; L14/14M [n = 121]; and L16/16M [n = 132]). Patients with myelodysplastic syndromes generally were not treated until they developed acute leukemia, but were then entered and included in the results. Secondary leukemias following treatment of other neoplastic diseases were not included. The complete remission rates were fairly constant between 47 and 64% and the median durations of remissions were between 9 and 21 months. The intensive treatment L14 and L16 protocols were associated with more early deaths and did not result in a significantly improved remission incidence or duration or survival. With all protocols, the majority of relapses occurred within the first 2 years, but relapses continued to occur at a decreasing rate for 4 years and occasionally even later. Whereas a small fraction (approximately 10 to 15%) of adults with ANLL are now apparently being cured with combination chemotherapy, despite intensive efforts there has been little improvement during the last decade and more selective and effective forms of treatment are urgently needed.

Results of a pilot study for the treatment of childhood acute nonlymphoblastic leukemia

Eighteen children with acute nonlymphoblastic leukemia were entered on a pilot protocol. The drugs used were vincristine, daunorubicin, cytosine arabinoside, and prednisolone for remission induction, high-dose cyclophosphamide together with vincristine and mercaptopurine for consolidation, and cycles of vincristine, prednisolone, mercaptopurine, methotrexate, and daunorubicin for maintenance therapy. Prophylactic central nervous system therapy (cranial radiotherapy 2400 rad and intrathecal methotrexate 10 mg/m2 for five doses) was given once remission had been achieved. Fourteen of the 18 children (78%) achieved complete remission (CR) and 50% of those achieving CR remain in CR for 35+ to 87+ months. Survival for all children ranges from 2 to 88+ months with 50% remaining alive for 36+ to 88+ months. The protocol was well tolerated with minimal side effects. These results together with those of other recently reported studies indicate an improving prognosis for acute nonlymphoblastic leukemia in childhood.

Treatment of acute myelogenous leukemia in children

Progress in the treatment of childhood AML has not equalled the advances obtained in the management of ALL. Two recent chemotherapy studies (i.e. VAPA and BFM 78), however, reported marked increase in the proportion of long-term remissions. The initial therapy of the cooperative study BFM 78 consisted of two 4-week phases of intensive induction/consolidation with 7 different drugs and cranial irradiation followed by maintenance with thioguanine and cytosine arabinoside for 2 years and additional adriamycin during the first year. A total of 151 children with AML were enrolled in the study from 30 centers. Of these 119 (79%) patients achieved complete remission. After a median observation time of 34 (14-57) months, there have been 46 relapses. CNS was involved in 6 of these relapses. Life table analyses revealed the following probabilities after 4 1/2 years: survival: 46%; disease-free survival: 41% (total group), 52% (remission group); disease-free interval 56% (remission group). The risk of relapse appears to decrease considerably after 2 1/2 years. No risk factors for the occurrence of relapse have been identified.

Down syndrome and acute leukemia in children: a 10-year retrospective survey from Childrens Cancer Study Group

Review of 5406 children with acute lymphoblastic (ALL) or nonlymphoblastic leukemia (ANLL) registered with Childrens Cancer Study Group (CCSG) since 1972 identified 115 patients (2.1%) with Down syndrome. The proportion of patients with Down syndrome was the same for ALL (2.1%) and ANLL (2.1%). Patients with ALL with and without Down syndrome did not differ significantly with respect to age at diagnosis, sex, race, morphology (FAB classification), cell surface markers, initial white blood cell count, pretreatment hemoglobin value, hepatomegaly, lymphadenopathy, presence of mediastinal mass, CNS disease at diagnosis, or prognostic group as defined by age and initial white blood cell count. Patients with ALL-Down syndrome less frequently had splenomegaly, had lower pretreatment platelet counts, and more often had normal or elevated IgG or IgA levels. In addition, they had a significantly lower rate of remission (81% versus 94%), a higher mortality during induction therapy (14% versus 3%), and a poorer overall survival with 5-year life table rates of 50% versus 65% (P less than 0.001). If an initial remission was achieved, there were no significant differences with respect to remission duration, survival, or disease-free survival. Patients with ANLL-Down syndrome were younger at diagnosis than those without Down syndrome. There was no significant difference in the remission rates between these patients. Analysis of findings in patients with ANLL provided results similar to those obtained for patients with ALL with regard to clinical outcome after achievement of an initial remission.

Evaluation of cyclocytidine in reinduction and maintenance therapy of children with acute nonlymphocytic leukemia previously treated with cytosine arabinoside: a report from Children's Cancer Study Group

A study of children in relapse with acute nonlymphocytic leukemia (ANLL) previously maintained in remission with combination chemotherapy including cytosine arabinoside (Ara-C) was undertaken by Children's Cancer Study Group (CCSG) to assess the efficacy of cyclocytidine (Cyclo-C), a depot Ara-C, compared to parenteral Ara-C given every 12 hr. The reinduction protocol consisted of daunomycin combined with either Ara-C (Regimen 1) or Cyclo-C (Regimen 2). One-hundred thirty eligible patients were entered on the randomized study. Hematologic toxicity was significant in both regimens and resulted in four drug-related deaths. Cardiac toxicity was observed in five patients, manifested only by abnormal echocardiogram or electrocardiogram patterns in three and congestive heart failure in two patients. Seventy-seven of 112 evaluable patients achieved M-1 or M-2A marrow remissions (69%): 46 of 60 on Regimen 1 (75%), 30 of 52 on Regimen 2 (60%). The remission rate between the two regimens was not significantly different. There was no significant difference in the duration of remission comparing maintenance cyclophosphamide combined with Ara-C or with Cyclo-C. Addition of VP-16 and CCNU to the maintenance therapy did not prolong the duration of remission. This study indicates that patients with childhood ANLL previously treated with Ara-C and daunomycin can obtain a successful second remission. A single daily subcutaneous dose of Cyclo-C was found to be as efficacious as Ara-C given intravenously every 12 hr. The single dose schedule provides a convenient way to treat patients with relapsed ANLL in the outpatient setting.

Early death in acute leukemia in children

Therapy for acute leukemia in children has improved dramatically in recent years so that early death is rare. A subset of patients with extreme elevation of the WBC at diagnosis have been noted to have a higher rate of early death. We reviewed our experience with acute leukemia in children retrospectively over a 10 year period to assess the incidence and outcome of this problem. Nine early deaths occurred in a total of 185 cases (4.9%). One hundred and sixty patients presented with WBC less than 100,000/mm3 at diagnosis and four (2.5%) early deaths occurred. Twenty-five patients presented with WBC greater than 100,000/mm3 at diagnosis and five (20%) early deaths occurred (p less than 0.001). While early death in acute leukemia in children is uncommon (4.9%), patients with extremely elevated WBC at diagnosis have a significantly higher risk of early death.

Acute promyelocytic leukemia in children

Sixteen children (ages 2--17) with acute promyelocytic leukemia (APL) were studied retrospectively. Diagnosis was based on clinical features and morphological criteria of the FAB classification. Bleeding diathesis was the predominant presenting symptom (greater than 85%), associated with laboratory findings of disseminated intravascular coagulation (DIC). Extramedullary manifestations included skin rash in six patients, gum infiltration in two, and meningeal leukemia in two. Induction therapy consisted of cytosine arabinoside and an anthracycline, with or without other agents. Prophylactic heparinization was given to 12 patients. Six patients (37.5%) failed to achieve remission and died, secondary to hemorrhage in three, and secondary to infection in the remaining three patients. The median duration of remission was 14 months, and the median survival for responders was 21 months. One meningeal leukemia preceded bone marrow relapse despite intermittent intrathecal chemotherapy for prophylaxis. Three patients remain in continuous complete remission 3 years after initial diagnosis. Although childhood APL shares many features of its adult counterpart, the high frequency of extramedullary manifestations and mortality secondary to neutropenia deserves separate attention.

Characteristics of children with acute nonlymphocytic leukemia in long-term continuous remission: a report for Childrens Cancer Study Group

Children and young adults less than 18 years of age with acute nonlymphocytic leukemia who remained in long term bone marrow and extramedullary remission for two years or longer since starting maintenance were compared to the remaining responders for the following characteristics: cell type, sex, age at diagnosis, race, pretreatment, white blood count, length of time from start to induction therapy to achievement of an M1 marrow, marrow rating at day 56 of therapy, marrow rating at the start of maintenance therapy, and specific study. Forty-eight patients of a group of 333 qualified as having long term remission (14.4%). Multivariant analysis indicated that patients between the ages of 3 and 10 years (p = 0.003) as well as the length of time to achieve an M1 marrow from the start of treatment (p = 0.03) were the only characteristics associated with achievement of a long term remission. Maintenance therapy was discontinued in 15 patients from 2.5 to 4.8 years after start of maintenance and all patients remained in bone marrow remission of periods from 0+ to 3.0+ years after stopping treatment. Of the 33 who have remained on a continuous maintenance therapy 12 have had bone marrow relapses. These data confirm the prognostic value of age and length of time to achieve remission during induction in acute nonlymphocytic leukemia and suggest that there may be no significant benefit from maintenance therapy continued beyond 2 years for patients in their initial remission.

Marrow transplantation for children with acute nonlymphoblastic leukemia in first remission

Thirteen children between the ages of two and 17 years with acute nonlymphoblastic leukemia in first remission were transplanted from HLA matched sibling donors. They were transplanted at a median of four months [2-8] following diagnosis. The preparative regimen of cyclophosphamide and total body irradiation was well tolerated. Two patients died of pneumonia 66 and 94 days following transplant. One patient relapsed at 431 days, and died of leukemia at 490 days. Ten are living in remission 20-53 months following transplantation. None are on maintenance chemotherapy, and all lead normal lives. As yet, growth is not impaired.

Progress in the treatment of childhood acute leukemia: a review

The dramatic improvements in the survival experience for children diagnosed with acute leukemia are analyzed using data collected through hospitals participating in the National Cancer Institute's End Results Group Program between 1950 and 1973. Children under 15 years of age who were diagnosed with both acute lymphocytic leukemia (ALL) and acute nonlymphocytic leukemia (ANLL) showed moderate improvements in the 1950s, but beginning in the 1960s those with ALL did far better. Statistically significant differences at the 0.05 level were noted between their three-year survival rates for all cohorts analyzed between 1960 and 1973. For the 1970-1973 cohort, three-year survival rates were 49% and 20% for ALL and ANLL, respectively, and five-year survival rates were 34% and 12%. Between 1950 and 1976 the age-adjusted incidence rate for all childhood leukemias remained relatively stable in a sample of five geographic areas, changing from 4.6 per 100,000 children under 15 years of age to 4.3 per 100,000. In contrast, the corresponding age-adjusted mortality rate fell approximately 45% over the same period, from 4.4 per 100,000 to 2.4 per 100,000.

Treatment of acute myelogenous leukemia in children and adults

We designed a protocol to address the problem of relapse from complete remission in acute myelogenous leukemia. Patients in remission were treated for 14 months; early and later intensification of chemotherapy, sequential drug combinations, and high-dose continuous infusions of cytarabine were included. Eighty-three consecutive patients under 50 years of age were entered into this study from February 1976 to October 1979. The rate of complete remission is 70 per cent. A Kaplan-Meier analysis predicts that 49 +/- 17 per cent of patients (mean +/- 2 S.D.) who entered complete remission will remain free of disease at two years. Durations of complete remission for patients in the 0 to 17-year and 18 to 50-year age groups are comparable.

Acute nonlymphocytic leukemia

The discovery of cytosine arabinoside, and then the anthrocycline antibiotics, 6-thioguanine, vincristine, cyclophosphamide, and other drugs, has added to the armamentarium of known effective agents. The use of combination chemotherapy, the recognition of the need during induction for virtual marrow aplasia to obtain a remission, and recognition of the predilection of the disease for the central nervous system requiring prophylaxis constitute major advances. The impediment to long-term survival is the lack of effective maintenance therapy.

Improved remission induction rate with D-ZAPO but unimproved remission duration with addition of immunotherapy to chemotherapy in previously untreated children with ANLL

In 163 children with acute nonlymphocytic leukemia (ANLL), a D-ZAPO induction program consisting of daunomycin, 5-azacytidine, cytosine arabinoside, prednisone, and vincristine resulted in a remission rate of 71.8%. Immunologic therapy was employed during maintenance with the aim of prolonging remission and improving survival. The administration of immunotherapy consisting of a mixture of bacillus Calmette-Guérin (BCG) and allogenic acute myelomonocytic leukemic cells injected intradermally on day 14 of each of the first three monthly cycles of 6-thioguanine for ten days, 5-azacytidine and cytosine arabinoside for four days, and vincristine for one day did not improve remission duration or survival compared to that due to chemotherapy alone. Important prognostic factors identified in this study included a remission induction rate significantly better for females than males (P = 0.04), for children between the ages of 5 and 10 years compared to those greater than this age group (P = 0.01), and a prolonged remission duration (P = 0.04), and survival (P less than 0.01) for patients with initial white blood counts of less than 20 x 10(9)/liter.