Maintenance and consolidation therapy in AML

Therapy of acute myelogenous leukemia

Treatment of acute myelogenous leukemia (AML) is divided into remission induction and post-remission therapy. Remission induction is usually with cytarabine and an anthracycline. Daunorubicin is commonly used but recent data suggest idarubicin or mitoxantrone are equally effective, possibly better. High-dose cytarabine has also been used for remission induction but is not proven superior. Post-remission treatment is typically with two or more courses of drugs similar to those used for remission induction. Other studies use non-cross resistant drugs and/or high-dose cytarabine. Although some data favor use of high-dose cytarabine, no approach is clearly superior. There is considerable controversy whether persons in first remission and with an HLA-identical sibling should receive a bone marrow transplant immediately or after relapse. Although transplant results appear superior, especially in persons less than 20 years of age, the most effective strategy may be reserving transplants for persons failing chemotherapy. This strategy also applies to persons receiving autologous transplants or transplants from alternative donors, like HLA-matched related or unrelated persons.

A randomized comparison of intensive maintenance treatment for adult acute myelogenous leukemia using either cyclic alternating drugs or repeated courses of the induction-type chemotherapy: AML-6 trial of the EORTC Leukemia Cooperative Group

Out of 515 evaluable patients (median age, 47 years) who entered the study from 1983 to 1986, 67.4% achieved complete remission (CR) after one cycle (256) or two cycles (91) of daunorubicin (DNR) (45 mg/m2 days 1-3), cytosine arabinoside (Ara-C) (200 mg/m2 i.v. days 1-7), and vincristine (VCR) (1 mg/m2 day 2). A partial remission was achieved by 3.7% of patients, 15% were resistant, 11.3% died during hypoplasia, and 2.7% died during induction. Patients achieving CR received one consolidation course in which administration of DNR was limited to 1 day. Two hundred and forty-eight patients were randomized for six courses of maintenance every 6 weeks: either DNR + VRC day 1 + Ara-C s.c. days 1-5, or AMSA 150 mg/m2 day 1 alternating with high-dose (HD)-Ara-C 3 g/m2 q12 h day 1 + 2 or 5-azacytidine 150 mg/m2 days 1-3. Two hundred and thirty-three patients were randomized when bone marrow transplantation (BMT) had not been planned or performed and 15 patients were randomized before the BMT. Sixty patients received BMT, 17 autografts, and 43 allografts. Median time from CR to BMT was 15 weeks. Forty-two patients were not randomized mainly because of toxicity or treatment refusal. Median DFS for both chemotherapy groups was 12 months and 23% were alive at 4 years. Median survival from CR was 22 months, and 34% were alive at 4 years. There was no difference in disease-free interval (DFI) and disease-free survival (DFS) between the two chemotherapy arms. Of 60 transplanted patients, 42% were alive at 4 years.(ABSTRACT TRUNCATED AT 250 WORDS)

[Post-remission treatment of acute leukemia in adulthood: allogeneic bone marrow transplantation or chemotherapy?]

The impact of bone marrow transplantation and chemotherapy on remission duration and survival in acute leukemia is controversial. Most studies on either procedure deal with selected patients and lack randomized or concurrent controls; many exclude high-risk subgroups. There are only a few preliminary reports on the direct comparison between bone marrow transplantation and intensive chemotherapy. Considerable controversy remains as to whether patients with AML in first remission who have an HLA identical sibling should receive a bone marrow transplant at that time or whether the transplant should be delayed until relapse or second remission. In patients under the age of 25 years, results of bone marrow transplantation are considered to be equivalent or superior to those achieved with chemotherapy. Because of a high lethality rate few results suggest that survival of patients transplanted during first remission is not superior to that obtained by intensified chemotherapy; however, the relapse incidence is decreased. In recent years, results in adult ALL, treated with various intensified programs, have improved considerably and are nearly comparable to those obtained in childhood ALL. Therefore, allogeneic bone marrow transplantation is usually performed in standard risk patients during second remission and, if relapse occurs within the first three years. It is not clear at present whether ALL high-risk patients will benefit from bone marrow transplantation during first remission.

Myelodysplastic relapse of de novo acute myeloid leukaemia with trilineage myelodysplasia: a previously unrecognized correlation

We describe the occurrence of an unusual mode of relapse in six of 24 patients who presented with de novo acute myeloid leukaemia (AML) associated with trilineage myelodysplasia (TMDS). After the induction of complete remission (CR) by intensive chemotherapy in five patients and following bone marrow transplantation (BMT) in one, the myelodysplastic state, but not overt AML, recurred. Relapse of myelodysplasia occurred at a median of 147 weeks (50-520) from presentation and in two instances was followed a year later by AML. In five cases, myelodysplastic relapse was treated with low-dose cytosine arabinoside given alone or with other chemotherapeutic agents. Three patients remain in CR after 1, 2 and 5 years. The reappearance of myelodysplastic features in these six patients was strongly correlated with the presence of TMDS at presentation of the AML. It was not observed once in the 136 AML patients, treated similarly, who did not have associated TMDS at presentation (P less than 0.001). Thus, relapse with myelodysplasia is not an effect of chemotherapy as has been previously postulated.

Survival in acute myeloblastic leukemia is not prolonged by remission maintenance or early reinduction chemotherapy. The Toronto Leukemia Study Group

A role for post-induction chemotherapy for adult patients with acute myeloblastic leukemia in remission has not been established. We have studied 125 patients with acute myeloblastic leukemia in complete remission to determine the effect on survival of remission maintenance therapy and of early reinduction therapy given at the time of predicted imminent relapse. Following remission induction with 6-thioguanine, cytosine arabinoside and daunorubicin (TAD), all patients received consolidation therapy with these same three drugs. Forty-three patients were randomized to arm A, continuing chemotherapy; 40 patients were randomized to arm B, no further chemotherapy until morphological relapse; and 42 patients were randomized to arm C, no further chemotherapy until an increase in myeloblast associated antigens was detected in bone marrow by means of antimyeloblast heteroantisera. The median durations of complete remission, age adjusted, for the three groups are not significantly different: 15.7 months for group A, 16.2 months for group B and 14.1 months for group C. The age adjusted median survivals for the three groups are also not significantly different: 17.6 months for group A, 21.8 months for group B and 18.8 months for group C. Quality of life was determined to be superior for patients having no further maintenance therapy (arms B and C). We conclude that our patients receiving induction and consolidation therapy with TAD did not benefit from remission maintenance or early reinduction chemotherapy, and had an improved quality of life if no maintenance therapy was given.

Prospects for cure in leukaemia

Patients with acute leukaemia have normal or near normal numbers of haemopoietic stem cells in their marrow at diagnosis. Remission is achieved when the administration of cytotoxic drugs eradicates the bulk of the leukaemic population while sparing normal haemopoiesis. The mechanism by which chemotherapy seems to act in this selective manner is essentially unknown. Nevertheless, remission rates of 80-95% can be achieved in children and in 50-80% of adults with acute leukaemia. Attempts to cure patients in remission may entail either "continuing curative chemotherapy" or "supralethal" doses of chemoradiotherapy followed by autologous or allogeneic bone marrow transplantation. The relative merits of these different methods remain highly controversial but chemotherapy is usually the preferred method of continuing treatment for children with acute lymphoblastic leukaemia in first remission; and allogeneic transplantation is recommended for younger adults with acute myeloid leukaemia who have suitable HLA-identical sibling donors. The role of autografting is still experimental. Patients with chronic myeloid leukaemia can achieve long term remission and probably cure following allogeneic bone marrow transplantation but the resultant risks of mortality are still appreciable. Chronic lymphocytic leukaemia currently remains incurable.

Clinical and laboratory features of de novo acute myeloid leukaemia with trilineage myelodysplasia

Primary myelodysplastic syndromes progress to acute myeloid leukaemia (AML) in about 30% of cases. We have sought evidence of pre-existing trilineage myelodysplasia (TMDS) using the FAB criteria (1982) in 160 consecutive cases of primary de novo AML. TMDS was found in 24 cases (15%) including two of 33 cases of M1 (6%), four of 40 cases of M2 (10%), none of 18 cases of M3, five of 31 cases of M4 (15%), six of 30 cases of M5 (20%), all of six cases of M6 and one of two cases of M7. The median presentation bone-marrow blast-cell count in the 24 AML/TMDS cases was 53% (30-90%) and 82% (45-100%) in the 136 cases of AML without TMDS. 60% of the AML/TMDS bone-marrow aspirates contained fewer than 60% of blasts compared with only 11% of those from AML without TMDS (P less than 0.001). In AML the occurrence of symptomatic cytopenias when the marrow blast-cell count is below 60% and the peripheral blood blast-cell count is below 20% is highly correlated with dysplastic haemopoiesis (P less than 0.001).

Osteolytic tumors in acute megakaryoblastic leukemia

A patient with soft tissue tumors and osteolytic bone lesions produced by acute megakaryoblastic leukemia is described. This appears to be the first report of this complication. The management and significance of this presentation are discussed.

Selective sparing of enterochromaffin cells in graft versus host disease affecting the colonic mucosa

Graft versus host disease affecting the large bowel causes destruction of the crypt epithelium. There is a selective sparing of enterochromaffin cells in the majority of cases. As a consequence, single as well as small clumps of enterochromaffin cells are to be seen in the sites formerly occupied by the destroyed crypt epithelium. The reason for this phenomenon is unclear, but it may be related to the fact that the enterochromaffin cells are end-stage and non-proliferating cells. This is useful diagnostically. However, cytotoxic drugs or irradiation must be excluded as the cause of the mucosal damage to bowel as there are theoretical reasons to expect that a similar phenomenon will be seen after these forms of therapy.

Long-term survivors of adult acute nonlymphocytic leukemia: fact or fiction?

From 1970 to 1982, remission rates from large series of patients with a median age of approximately 50 years continue to exceed 50% and in series of younger patients may be as high as 75%. These improved results have been due to the combination of cytosar and an anthracycline in RI programs. The current major question is whether or not "consolidation" therapy has improved long-term disease-free survival. Our current results, covering the decade 1970-1980 and using more and more intensive RC programs, do not demonstrate an increase in the percentage of long-term survivors. The results from 1980 to 1982 are encouraging, but must be tempered by the fact that late relapses of adult ANLL are becoming more frequent and 2-year follow-up is much too short an evaluation period. In addition, the prolonged survival in program D may be due to the more intensive RI program and not at all related to the RC. At the present time, our experience lends no support to the theory that more intensive RC programs meaningfully prolong long-term survival.