Therapeutic role of cell kinetics in acute leukaemia

In vitro co-stimulation with anti-CD28 synergizes with IL-12 in the generation of T cell immune responses to leukaemic cells; a strategy for ex-vivo generation of CTL for immunotherapy

The existence of an immune based graft-versus-leukaemia (GvL) effect highlighted the prospect of managing relapsed leukaemias with T cell-based adoptive immunotherapy. Thus, various strategies have been explored for the in vitro expansion of acute myeloid leukaemia (AML)-specific T cells. In a popular approach, AML blasts have been genetically modified to express co-stimulatory molecules essential for effective T cell priming. One such tactic has been the modification of AML cells to express the B7/CD80 co-stimulatory molecule that binds to CD28 on T cells initiating events that culminate in enhanced cytokine production, proliferation and development of effector functions by T cells. The success of these strategies has been limited by difficulties in attaining sufficient transduction efficiencies and associated high levels of CD80 expression. We demonstrate that these problems can be circumvented by using anti-CD28 monoclonal antibody. Furthermore, we show that the synergistic relationship between CD80/CD28 pathway and interleukin 12 cytokine (IL-12), documented in the generation of cytotoxic T lymphocytes (CTL) for solid tumours, also applies to AML. CD28/IL-12 synergy facilitated the proliferation of allogeneic T cells in response to stimulation with primary AML blasts. The synergy also favoured generation of a Th1-type immune response, evidenced by gamma interferon (IFN-gamma) secretion and facilitated naive and memory T cell proliferation. Unlike some methods of in vitro T cell expansion, use of CD28/IL-12 synergy left T cells in the physiologically appropriate CD45RA-/CCR7- subsets known to be associated with immediate cytotoxic functions.

Recurrent venous thrombosis as the presenting manifestation of acute lymphocytic leukemia: leukemic cell procoagulant activity is not responsible for the hypercoagulable state

The association of cancer with clinical abnormalities of blood coagulation, including superficial thrombophlebitis, deep vein thrombosis (DVT), and disseminated intravascular coagulation (DIC) is well-known, particularly in patients with solid tumors and acute promyelocytic leukemia (APL). Less commonly appreciated is the potential for the development of venous thromboembolic disease (TED) in patients with acute lymphocytic leukemia (ALL). Multiple mechanisms have been implicated for the activation of coagulation in these patients, with an emphasis on the contribution made by the procoagulant properties of the tumor cells themselves. We present two cases of patients with pre-B cell ALL, both of whom developed recurrent TED as the presenting manifestation of their leukemia and/or heralding relapse. The blast cells from one of the patients were studied for the presence of procoagulant activity (PCA) and by Northern blot analysis for tissue factor (TF) messenger RNA (mRNA). Neither PCA nor TF mRNA could be identified in highly purified populations of the lymphoblast cells. We conclude that recurrent TED can be a manifestation of ALL and that mechanisms other than the release of tumor cell procoagulants should be sought to explain the pathogenesis of thrombosis in some patients.

Cell kinetics with in vivo bromodeoxyuridine assay, proliferating cell nuclear antigen expression, and flow cytometric analysis. Prognostic significance in acute nonlymphoblastic leukemia

BACKGROUND

The proliferative characteristics of acute nonlymphoblastic leukemia (ANLL) were studied in vivo, and data were correlated with response to chemotherapy and survival.

METHODS

Sixty-five patients with untreated ANLL and 15 patients with solid tumors and normal bone marrow (BM) received 250 mg/m2 of bromodeoxyuridine (BUdR); bivariate flow cytometric (FCM) analysis then was used to measure cell BUdR incorporation and DNA content to obtain a complete set of kinetic parameters (i.e., BM BUdR-labeling index, DNA-synthesis time, potential doubling time [Tpot], and cell production rate). The percentage of blasts with positive results for proliferating cell nuclear antigen (PCNA) also was obtained by FCM analysis on the same BM samples, and these kinetic parameters were derived specifically for the ANLL proliferating compartment (growth fraction). Induction therapy, consisting of vincristine, arabinosylcytosine, and daunomycin, was administered subsequently to the patients with ANLL.

RESULTS

Overall ANLL proliferative activity was lower than normal myelopoiesis, and a short Tpot was found to be a favorable factor for achieving complete remission (CR), the duration of CR, and survival. When the growth fraction was considered, however, ANLL proliferative activity was higher and more like that of normal BM. The kinetic differences detected in the PCNA-positive cells of patients with CR and no response and those with CR and survival durations above and below the median values for the entire series were highly significant in univariate analysis and retained a strong independent prognostic value when multivariate analysis was performed.

CONCLUSIONS

These data show the clinical feasibility of a detailed study of cell kinetics by means of new FCM-based techniques and reinforce the clinical value of pretreatment proliferative activity in ANLL.

Time-variations of pretreatment peripheral blood S + G2/M-phase size determined by flow cytometry in adult acute myeloid leukaemia

The circadian and seasonal variations of pretreatment proliferative activity of peripheral blood (PB) as PB S + G2/M-phase size was determined by flow cytometry in 61 adult patients with acute myeloid leukaemia (AML). Pretreatment PB S-phase (p less than 0.002), G2 + M-phase (p less than 0.008) and S + G2/M-phase size are statistically correlated to the time of sampling, with the highest phase size at the end of the day. Time-variations of the blast cell count are slightly significant (p = 0.049). Cytological diagnosis-related differences in S + G2/M-phase (p less than 0.003) and white blood cell count (p less than 0.04) time-variations are observed. For all patients, no seasonal variations can be drawn, but in AML 1 (p less than 0.029) and AML 4-5 patients (p less than 0.003), the circadian variations of S + G2/M are affected by the seasons. The present results suggest that time may be taken into account in the monitoring of chemotherapy in acute leukaemia.

Clinical significance of fibrinopeptide A in acute lymphocytic and non-lymphocytic leukaemia

Fibrinopeptide A (FPA) was systematically investigated in 74 patients with acute leukaemia at different stages of the disease (50 with non-lymphocytic leukaemia, ANLL; 24 with lymphocytic leukaemia, ALL). At diagnosis, 75% of the cases had high FPA levels (86% in ANLL and 54% in ALL) with significantly higher levels in ANLL than in ALL (13.4 vs 4.4 ng/ml; p less than 0.001). Patients with DIC (20 cases in ANLL and 1 case in ALL) had significantly higher levels (p less than 0.001). FPA levels were neither correlated with fibrinogen or FDP levels nor with blast cell count. During chemotherapy, median FPA did not show significant changes whereas, at the end of therapy, a return toward normality was generally observed both in ALL and ANLL apart from the group of patients with acute promyelocytic leukaemia. Among the 24 patients who entered post-remission follow-up (13 ANLL and 11 ALL), 10 cases out of the 11 relapsing (6/6 with ANLL and 4/5 with ALL) had increased FPA 1 to 2 months before the ascertainment of the relapse. However, 16% and 9% of the samples obtained on different occasions, respectively from ANLL and ALL cases in maintained first remission, showed FPA above the normal limit. This study demonstrates that subclinical activation of blood coagulation, as indicated by high FPA level, is common both in lymphocytic and non-lymphocytic leukemia and suggests that this phenomenon is related to disease activity.

A new method for studying cell cycle characteristics in ANLL using double-labeling with BrdU and 3HTdr

Ten patients with acute nonlymphocytic leukemia (ANLL) received bromodeoxyuridine (BrdU) at 100 mg/M2 intravenously over 1 h. BrdU is incorporated into the DNA by S-phase cells and was detected by using a monoclonal anti-BrdU antibody in the bone marrow aspirate (BM) and biopsy specimens obtained at the end of the infusion. Additionally, BM was incubated in vitro with tritiated thymidine (3HTdr) and processed by our previously described double-label method. This allowed us to measure the duration of S-phase (Ts) and total cell cycle time (Tc) of myeloblasts. Data revealed a higher number of S-phase cells from biopsies (21%) than BM (5%). The Ts ranged from 9 to 35 h and Tc ranged between 36 and 152 h in different patients. Using this method, data are available within 48 h and if shown to be clinically relevant, may be useful for prospective planning of therapy in individual patients.

Residual leukemia cannot be detected in very early remission peripheral blood stem cell collections in acute non-lymphoblastic leukemia

We have used a combined cell culture and cytogenetic approach to study the level of residual leukemia during the very early remission (VER) phase of acute non-lymphoblastic leukemia. Clonogenic leukemic cells were induced to proliferate by phytohemagglutinin-stimulated leucocyte conditioned medium and identified by a leukemia-associated karyotype t(8;21) and a morphological marker (Auer rod). When leukemic blasts were cultured, the leukemic karyotype and Auer rods were most readily detected after 3-9 days. When VER blood cells were cultured, no leukemia-associated karyotype or Auer rods could be detected. Based on the number of VER blood cell derived metaphases analysed, the incidence of leukemic blasts among dividing cells is less than 2%.

Persistence of bone marrow lymphocytosis after induction treatment in common acute lymphoblastic leukemia. Marker analysis and significance

In a series of 22 adult acute lymphoblastic leukemias expressing the common acute lymphoblastic leukemia antigen (cALLA +), eight had marrow lymphocytosis greater than 30% (43 +/- 12%) with disappearance of marrow lymphoblasts and correction of bone marrow insufficiency at the end of the induction treatment. Four of these patients were studied for the cALL antigen at this time and had persistence of this immunological marker (62 +/- 15% of the mononuclear bone marrow cells). The evolution of these patients suggests that these patients were not in complete remission and emphasizes the usefulness of cALLA determination in cases with borderline excess of marrow lymphocytes.

Pretreatment of cytokinetics in acute myelogenous leukemia. Age-related prognostic implications

To determine the clinical and biologic relevance of cellular kinetics in leukemia, DNA flow cytometric analysis was performed on bone marrow biopsy specimens from 148 previously untreated adult patients with acute myelogenous leukemia. The proportion of cells in synthesis, second growth, and mitosis (S + G2M) ranged from 4% to 33% with a median of 14%. The overall incidence of complete remission was not affected by the pretreatment cell cycle distribution. As in earlier studies, there was a marked decline in remission rate with advancing age from 73% for patients age less than or equal to 50 yr to 50% for those greater than 50 (P less than 0.01). Although not affecting remission induction overall, an increasing proportion of cells in S + G2M phase was favorable in patients under the age of 50 yr, but was associated with a progressive decline in remission rate in older patients (P = 0.01). This age-related divergent effect of cell cycle kinetics on initial response to therapy was confined to the less favorable subgroup of patients with karyotypic abnormalities, whereas patients with normal diploid cytogenetics had a consistently higher response rate regardless of proliferative activity. A positive correlation was also observed between percent of S + G2M cells and the proportion of diploid metaphases in young patients, contrasting with a negative correlation in the older age group. Our observations strongly suggest that the well-recognized prognostic effect of age on remission induction is not entirely host-mediated, but is at least partly an expression of disease-intrinsic differences between young and older patients.

Cell-cycle, protein content, and nuclear size in acute myeloid leukemia

Simultaneous analysis of DNA and cellular proteins provides information on cell proliferation and metabolism. Cellular protein content coupled with nuclear geometric parameters can be used to evaluate cellular maturation and differentiation. In this study, leucoblasts from 50 cases of adult acute myeloid leukemia were analyzed by flow cytometry, and semiautomatic morphometry was performed on bone marrow smears. Ethanol-fixed bone marrow blast cells were stained for DNA with propidium iodide (PI) and for proteins with fluorescein isothiocyanate (FITC). On the resulting FITC versus PI histograms we defined the cells with low protein content which are associated with a nonproliferating subpopulation (LPC fraction). Low protein content fraction and S-phase are correlated (p less than 0.01). The LPC fraction values are more dispersed than S-phase values and thus should indicate more clearly eventual differences between cellular populations. This hypothesis has been tested with the prognostic significance of cell-cycle variables: The LPC fraction was significantly higher in the complete remission group than in the other (p less than 0.01), while S-phase did not show any difference. The peak value of the protein content histograms is significantly lower in the granulocytic leukemias (M1, M2, M3) than in the leukemias with a monoblastic component (M4, M5). Furthermore, we showed that the differentiation and the maturation of the myeloid blast cells modify the nuclear size. The combination of these two parameters provides useful information for cytological classification.

An antigen related to the phenotype of multi-drug resistance can be induced in vivo and used as a target for immunotherapy of rat leukemia

Several laboratories have reported that new plasma membrane peptides appear in rodent and human cells after induction of in-vitro resistance to vinca alkaloids, anthracyclines and other anti-neoplastic drugs. Recently, murine monoclonal antibodies have been produced that recognize surface components of such drug-resistant cells. The work presented here describes the development of an in-vivo animal model of this phenomenon using a rat myeloid leukemia. Brown Norway rats were made leukemic with promyelocytes of the BNML line and subsequently were treated with 7.7 mg kg-1 of daunorubicin. After eight cycles of passage-treatment-regrowth, the resulting cells reacted with this antibody in immunofluorescence and cytotoxicity assays. Animals injected with cells that had been pre-incubated with antibody in the absence of complement survived significantly longer than did the controls. Further prolongation of survival occurred when the cells were treated with a second antibody of a different specificity. These results demonstrate that some of the changes associated with in-vitro drug resistance occur also in vivo and potentially may be exploited as a focus for immunotherapy.

High levels of circulating haemopoietic stem cells in very early remission from acute non-lymphoblastic leukaemia and their collection and cryopreservation

Circulating myeloid progenitor cells (PB CFU-GM) were measured in the peripheral blood of 13 patients with acute non-lymphoblastic leukaemia (ANLL) as they entered first remission. The mean of the recorded peak levels was 2796 X 10(3) CFU-GM/l, representing a 25-fold increase above the mean value in normal subjects. These elevated levels of PB CFU-GM occurred regularly during the very early remission phase when platelet counts rose rapidly. Five of the patients had PB mononuclear cells collected by continuous-flow leukapheresis during this early recovery phase. CFU-GM were assayed as a measure of the number of haemopoietic stem cells in each collection. The cells were concentrated and then cryopreserved in liquid nitrogen. Leukapheresis was also performed on five normal subjects for comparison. Low numbers of CFU-GM were harvested from normal subjects, mean 0.33 +/- 0.06 X 10(4) CFU-GM/kg body weight for each leukapheresis. In ANLL patients entering remission, however, very large numbers of CFU-GM were regularly harvested. A mean of 11 +/- 2 X 10(4) CFU-GM/kg body weight were cryopreserved after each leukapheresis, representing 5 times the number of CFU-GM considered necessary for successful autologous haemopoietic reconstitution. Haemopoietic stem cell viability was assessed after varying periods of cryopreservation. There was no significant stem cell loss after up to 24 months storage. Thus, it is possible to collect and cryopreserve large numbers of CFU-GM and by inference pluripotent haemopoietic stem cells from the peripheral blood of patients with ANLL during very early remission. The possible biological and therapeutic implications are discussed.

Male reproductive capacity may recover following drug treatment with the L-10 protocol for acute lymphocytic leukemia

Six men with acute lymphocytic leukemia (ALL) were studied prospectively to assess the effect of treatment with the L-10 protocol on reproductive capacity. Before therapy three men had fathered children (two, two children; one, three children); the others were sexually mature although no fertility studies had been done prior to or during their treatment. Each patient had a minimum of 3 1/2 years of continuous chemotherapy as part of this study. Semen analysis was done 10 to 52 months (median, 31.5 months) after completion of therapy. One patient had lower than normal sperm concentration but near normal total sperm count and normal motility; the others had a normal sperm concentration and motility. Sperm nuclei were isolated from each sample and analyzed by flow cytometry for resistance to DNA denaturation in situ; all samples had relatively high resistance to denaturation, consistent with a normal, fertile reproductive status. After completion of therapy, one patient fathered a normal child, and a second patient fathered one child with multiple congenital malformations followed by a second child who was normal.

In vitro culture of clonogenic leukaemic cells in acute myeloid leukaemia: growth pattern and drug sensitivity

Bone marrow from 43 of 45 AML patients grew leukaemic colonies in culture with a technique using methyl-cellulose semi-solid medium and stimulation with PHA-leucocyte conditioned medium. Plating efficiency was significantly greater in M4FAB subtypes than in M1 or M2. The presence of Auer rods in cultured cells and the existence of cytogenetic abnormalities in both fresh and cultured blast cells in one patient confirmed the leukaemic origin of these colonies. These clonogenic cells were closely related to the growth fraction, as demonstrated by a high suicide index and a linear correlation between percentage of bone marrow blasts in S phase and plating efficiency. In vitro CFU-L sensitivity to cytosine-arabinoside (ARA-C) and to adriamycin (ADR) was tested in 22 patients treated with these two drugs. In the group sensitive in vitro to ARA-C (10 patients), 70% entered complete remission. In the resistant group (12 patients), only 25% had complete remission while 75% had resistant disease. Eight of 14 patients sensitive to ADR in vitro achieved complete remission, while five were resistant to chemotherapy. On the other hand, six of eight patients resistant in vitro were resistant in vivo. When drug sensitivities to ARA-C and ADR were cumulated, an excellent in vitro to in vivo correlation was found when the patient was sensitive or resistant to both drugs in vitro.

Cell kinetics in acute leukemia: a critical reevaluation based on new data

The current study was undertaken to compare biopsy and aspiration sampling techniques for reliable cell kinetic analysis in acute leukemia and to reevaluate the clinical significance of cell kinetic data in this disease. Ad 1: One hundred forty-three paired simultaneously taken marrow aspirates and Jamshidi biopsies from 61 patients with acute nonlymphocytic leukemia (ANLL) were compared by means of flow cytometry (FCM) for cellular DNA and RNA measurements, autoradiography for 3H-TdR labeling index and liquid scintillation counting for 3H-TdR uptake. Aspirates were found unreliable for pretreatment evaluation and for monitoring of drug induced cell kinetic perturbations due to contamination with peripheral blood. Aspiration should, therefore, be replaced by marrow biopsy which provides reliable sampling of bone marrow for cell kinetic studies. Ad 2: FCM S-phase index determined from biopsy material was not found predictive for therapeutic response in 43 patients with ANLL treated with two different induction regimens. In one of the two protocols, changes in FCM S-phase index after 48 hours continuous infusion of cytosine arabinoside correlated significantly with clinical response and nonresponse, respectively.

Cytosine arabinoside influx and nucleoside transport sites in acute leukemia

Although cytosine arabinoside (araC) can induce a remission in a majority of patients presenting with acute myeloblastic leukemia (AML), a minority fail to respond and moreover the drug has less effect in acute lymphoblastic leukemia (ALL). The carrier-mediated influx of araC into purified blasts from patients with AML, ALL, and acute undifferentiated leukemia (AUL) has been compared to that of normal lymphocytes and polymorphs. Blasts showed a larger mediated influx of araC than mature cells, since mean influxes for myeloblasts and lymphoblasts were 6- and 2.3-fold greater than polymorphs and lymphocytes, respectively. Also, the mean influx for myeloblasts was fourfold greater than the mean for lymphoblasts. The number of nucleoside transport sites was estimated for each cell type by measuring the equilibrium binding of [(3)H]nitrobenzylthioinosine (NBMPR), which inhibits nucleoside fluxes by binding with high affinity to specific sites on the transport mechanism. The mean binding site numbers for myeloblasts and lymphoblasts were 5- and 2.8-fold greater, respectively, than for the mature cells of the same maturation series. The mean number of NBMPR binding sites for myeloblasts was fourfold greater than for lymphoblasts. Patients with AUL were heterogeneous since blasts from some gave values within the myeloblastic range and others within the lymphoblastic range. The araC influx correlated closely with the number of NBMPR binding sites measured in the same cells on the same day. Transport parameters were measured on blasts from 15 patients with AML or AUL who were then treated with standard induction therapy containing araC. Eight patients entered complete remission, while seven failed therapy, among whom were the three patients with the lowest araC influx (<0.4 pmol/10(7) cells per min) and NBMPR binding (<3,000 sites/cell) for the treated group. In summary, myeloblasts have both higher araC transport rates and more nucleoside transport sites than lymphoblasts and this factor may contribute to the greater sensitivity of AML to this drug. AraC transport varied >10-fold between leukemic blasts and normal leukocytes, but transport capacity related directly to the number of nucleoside transport sites on the cell. Finally, low araC transport rates or few NBMPR binding sites on blasts were observed in a subset of patients with acute leukemia who failed to achieve remission with drug combinations containing araC.

PHA-induced blast colonies and kinetic parameters in acute myeloid leukemia

The in vitro leukemic colony-forming ability of 30 acute myeloid leukemias tested after PHA stimulation was analyzed by comparing the CFU-GM growth pattern, the myeloblast [3H]thymidine index and the response to treatment. PHA-induced leukemic colonies were obtained in 15 out of 30 cases. No correlation was found between the FAB classification, the CFU-GM growth pattern and the PHA-induced colony growth. A significant correlation was observed between PHA-induced colony growth and [3H]thymidine labeling index (p less than 0.001). A correction was also noted between the presence of leukemic growth and the failure of the induction treatment (p less than 0.02). The proliferation of the clonogenic blastic subpopulation selected by this technique seems to be linked to a poor prognosis.

Bone marrow biopsy instead of 'marrow juice' for cell kinetic analysis. Comparison of bone marrow biopsy and aspiration material

Since cell kinetic bone marrow studies have so far exclusively been carried out on aspiration material and have yielded inconsistent or even contradictory results, we investigated the adequacy and reliability of aspirates for cell kinetic analyses in comparison to biopsies. Paired samples of bone marrow (133) were taken simultaneously by aspiration and Jamshidi biopsy from 48 patients with acute leukemias and 67 patients with non-leukemic disorders. Cell kinetic analysis by (1) flow cytometry (FCM) of cellular DNA and RNA content, (2) autoradiography for [3H]TdR pulse labelling indices and (3) liquid scintillation counting of [3H]TdR uptake revealed significantly higher values in biopsies (p less than 0.001) exceeding the corresponding results from aspirates on average by factors of 1.65 for FCM S-phase index, 1.90 for G0/1 cells with high RNA content, 1.82 for [3H]TdR LI and 1.90 for [3H]TdR uptake. In more than 70% of all samples results from biopsies were 1.1-11.4 times higher, indicating that aspirates were equivalent to biopsies in fewer tan 30% of cases. Cell kinetic analysis in vitro blood/biopsy mixtures and measurements of DNA synthesis rate in corresponding aspirates and biopsies revealed that these discrepancies are due to the contamination of aspirates with non-proliferating nucleated blood cells. Biopsy, however, was found to provide representative and reproducible sampling of marrow for cell kinetic studies and should replace the presently used aspirate already characterized as "unreliable marrow juice" by Dameshek et al. in 1937 [18].

EBV-positive Burkitt's lymphoma from Algeria, with a three-way rearrangement involving chromosomes 2, 8 and 9

Burkitt's lymphoma was diagnosed in male Algerian child presenting with abdominal and jaw tumours. Viral studies revealed that this non-endemic case was associated with the Epstein-Barr virus. Cytogenetic examination of tumour cells showed a complex three-way rearrangement involving chromosomes 2, 8 and 9. Our report indicates that, in Burkitt's lymphoma, not only simple but also complex translocation involving chromosome 8 may arise. This finding in a North African case emphasizes the need for more detailed study of the clinical, virological and cytogenetic features of Burkitt's lymphoma throughout the world.

Osteonecrosis in patients with malignant lymphoma: a review of twenty-five cases

A retrospective study of 25 patients with malignant lymphoma who had osteonecrosis of either the femoral or humeral head(s) was undertaken. The common factor present among all patients was the administration of intermittent steroid-containing combination chemotherapy. Seventeen Hodgkin's disease patients received chemotherapy predominantly consisting of an alkylating agent, vincristine, procarbazine, and moderate amounts of prednisone. The non-Hodgkin's lymphoma patients were on various moderate dosage steroid-containing protocols, except three who received prolonged high-dose steroid-containing chemotherapy regimens. Sixteen of the 17 Hodgkin's disease patients and five of the eight non-Hodgkin's lymphoma patients received radiotherapy to the bones that subsequently developed osteonecrosis. Two of the three non-Hodgkin's lymphoma patients who were not irradiated were treated with high-dose steroid-containing chemotherapy regimens. Symptoms developed in patients 12 months and 32 months after completion of chemotherapy and radiotherapy, respectively. Osteonecrosis was a long-term complication of treatment between 1970 and 1979 and occurred in 1.6% of the Hodgkin's disease and 0.12% of the non-Hodgkin's lymphoma patients treated. The authors conclude that the patients at highest risk for this complication are those who receive both radiotherapy to the affected bone(s) and intermittent steroid-containing multiple drug chemotherapy.

A four-year experience with anthracycline, cytosine arabinoside, vincristine and prednisone combination chemotherapy in 325 adults with acute leukemia

Combination chemotherapy with an anthracycline, Adriamycin or rubidazone, cytosine arabinoside, vincristine and prednisone resulted in a complete remission rate of 62% in 325 consecutive unselected adults with acute leukemia. The results by morphologic categories were 58% for acute myelogenous leukemia (AML), 70% for acute undifferentiated leukemia (AUL), and 77% for acute lymphoblastic leukemia (ALL). The median survival was 43 weeks. Ten percent of all patients are projected to be alive and in remission at five years. The median remission duration for the whole group was 51 weeks, durations being significantly longer for AML (60 wks) than ALL (30 wks) and AUL (21 wks). Central nervous system involvement was uncommon in AML (4%), but much more common in patients with AUL (37%) and ALL (32%). One in five complete responders with AML is projected to be in their first remission at five years off all chemotherapy. Age, sex, morphology, cytogenetic pattern, temperature of presentation, and presence of a documented preceding hematologic abnormality are found to be significant variables for response and survival.

Treatment of adult lymphoblastic leukaemia using cyclical chemotherapy with three combinations of four drugs (COAP, POMP, TRAP schedule)

Seventeen adult patients with previously untreated acute lymphoblastic leukaemia (ALL) were entered into a schedule of chemotherapy in which 3 combinations, each of 4 drugs, were administered in a predetermined cyclical rotation in combination with cranial irradiation and intrathecal injections of methotrexate. Of the 17 patients, 16 completed induction therapy and 15 (94%) entered remission. The only patient with T-ALL died before receiving any therapy. The median survival for all patients (17) was 22 months. Meningeal leukaemia did not occur during the haematological remission phase although 3 patients developed this complication following relapse. The authors conclude that the addition of cyclophosphamide and cytosine arabinoside to vincristine/prednisone provides excellent remission induction but the aggressive maintenance schedule employed has not led to significant long-term survival.

A long-term clinical follow-up of children with acute lymphoblastic leukemia treated with intensive chemotherapy regimens

One hundred and thirty-three children 15 years old and younger with acute lymphoblastic leukemia were treated with two different protocols. Both regimens consist of a multi-drug program, without CNS irradiation, administered for three years. Seventy-five children were enrolled on the first protocol, L-2; and 58 were treated on the subsequent regimen, L-10. Of the 70 evaluable patients on the L-2 program, 40 continue in complete remission from 72-111 months. Seventy-four percent of the children qualified for treatment cessation, and 59% have remained in continuous remission for six years. The estimated seven year disease-free survival for the 70 evaluable children on the L-2 protocol is 57% and for all entries is 53%. Of the 57 evaluable patients on the L-10 program, 35 are in complete remission from 15-67 months. The combined frequency of primary CNS leukemia for the two regimens is 7%. The off-therapy results of the L-2 protocol cannot be compared to the L-10 at present, but the on-therapy outcomes, despite the modifications that were designed to improve the L-10 regimen, are comparable.