Options for therapy in chronic myeloid leukaemia

Drugs targeted against protein kinases

Current treatments for cancer (surgery, radiation and chemotherapy) are successful for early stage localised disease but have severe side effects. New treatments are needed to increase the cure rate and life expectancy of patients. With the discovery of oncogenes, tumour suppressor genes and an understanding of their role in the development of the malignant disease, a new era of therapy has begun. Cancer is a manifestation of deregulated signalling pathways that mediate cell growth and programmed cell death. Protein kinases are essential elements in these signalling pathways. In the US, Novartis launched Gleevec (imantinib, STI-571) in May 2001 as the first anticancer drug whose mechanism of action is kinase inhibition. In Phase I trials, 23/24 patients with chronic myelogenous leukaemia (CML) had complete remissions and the drug is relatively non-toxic. Herceptin (trastuzumab) is a monoclonal antibody (mAb) against a member of the growth factor receptor family (HER-2/neu) that was launched in 1998 by Genentech for the treatment of breast cancer. Trastuzumab has an excellent antitumour profile, particularly when used in combination with doxorubicin and paclitaxol. These drugs are pioneering the treatment of cancer based on the molecular understanding of the disease. Numerous drugs that target growth factor receptors and their signalling pathways are in advanced clinical trials. Herein, antibodies against receptors and small molecule inhibitors of kinases in signalling pathways will be summarised. Inter-disciplinary preclinical studies have identified chemicals that target specific kinases. We believe that clinical studies of these agents will yield new anticancer agents that target specific diseases and that are less toxic than current agents.

Cardiac morbidity in advanced chronic myelogenous leukaemia patients treated by successive allogeneic stem cell transplantation with busulphan/cyclophosphamide conditioning after imatinib mesylate administration

Imatinib mesylate is useful for facilitating allogeneic stem cell transplantation (allo-SCT) in advanced-phase chronic myelogenous leukaemia (AP-CML) patients. However, although the side-effects of imatinib are usually minor, cardiac morbidity can develop as a latent adverse effect post SCT when a myeloablative SCT is given to patients taking imatinib. Two AP-CML patients who were treated with imatinib manifested severe cardiac dysfunction after an allo-SCT, whereas cardiac morbidity was not observed in 45 other patients who had not received imatinib. It would appear that exposure to imatinib may have an adverse impact on the heart in AP-CML patients who receive an allo-SCT conditioned with busulphan/cyclophosphamide.

Favorable outcome with STI571 (imatinib mesylate) and allogeneic stem cell transplantation in a case of Ph+ chemorefractory acute lymphocytic leukaemia

We present a patient with a Philadelphia chromosome positive (Ph+) acute lymphocytic leukaemia (ALL) refractory to standard induction chemotherapy. Treatment with the ABL-specific tyrosine kinase inhibitor STI571 (Glivec, Gleevec, imatinib mesylate) resulted in a complete haematologic and cytogenetic remission. Allogeneic stem cell transplantation from an unrelated donor could be undertaken while the patient was in STI571-induced complete remission from the leukaemia. At present, the patient has a 15-month post-transplantation follow-up and is in stable molecular remission as evaluated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) for the BCR/ABL fusion gene transcript. Our case demonstrates that STI571 can act as a bridge to potentially curative allogeneic stem cell transplant in otherwise poor prognosis Ph+ ALL.

Bcr-Abl variants: biological and clinical aspects

Bcr-Abl is an oncogene that arises from fusion of the Bcr gene with the c-Abl proto-oncogene. Three different Bcr-Abl variants can be formed, depending on the amount of Bcr gene included: p185, p210, and p230. The three variants are associated with distinct types of human leukemias. Examination of the signaling pathways differentially regulated by the Bcr-Abl proteins will help us gain better insight into Bcr-Abl mediated leukemogenesis.

Factors affecting duration of survival after onset of blastic transformation of chronic myeloid leukemia

We analyzed factors having an impact on response to treatment and survival in 78 consecutive patients with chronic myeloid leukemia (CML) in blastic transformation (BT) referred to the Hammersmith Hospital from January 1995 to December 2000. BT was defined as the presence of at least 30% blasts in blood or marrow or extramedullary blastic deposits. Immunophenotyping of blasts showed 57 myeloid, 19 lymphoid, and 2 biphenotypic. The median age of the patients was 39.1 years (range, 11.3-73.4 years), with 55 males and 23 females. The median survival for all patients after onset of BT was 8.2 months (95% CI, 6.4-10). Patients in lymphoid BT survived longer than those in myeloid BT (median, 11.2 months versus 6.9 months, P =.052). Initial treatment varied; 41 patients received cytotoxic drugs, 8 underwent allogeneic or autologous transplantation procedures, 21 received STI571 (imatinib mesylate, Gleevec), 1 received radiotherapy, and 7 received no therapy. Of the 25 (32%) patients who achieved a "second chronic phase" with first therapy, 6 of 21 (29%) were treated with STI571 and 19 of 50 (38%) were treated with chemotherapy, transplantation, or radiotherapy. Patients who achieved a second chronic phase survived longer than those who did not (median time from onset of BT 12.0 months versus 6.3 months, P =.0004). In multivariate analysis the finding of more than 50% blast cells in the blood and the presence of cytogenetic progression were independent adverse prognostic variables for survival. We conclude that survival after onset of BT has improved in recent years but is still unsatisfactory. We speculate that the combined use of STI571 with cytotoxic drugs may offer additional benefit.

Activity of a specific inhibitor of the BCR-ABL tyrosine kinase in the blast crisis of chronic myeloid leukemia and acute lymphoblastic leukemia with the Philadelphia chromosome

BACKGROUND

BCR-ABL, a constitutively activated tyrosine kinase, is the product of the Philadelphia chromosome. This enzyme is present in virtually all cases of chronic myeloid leukemia (CML) throughout the course of the disease, and in 20 percent of cases of acute lymphoblastic leukemia (ALL). On the basis of the substantial activity of the inhibitor in patients in the chronic phase, we evaluated STI571 (formerly known as CGP 57148B), a specific inhibitor of the BCR-ABL tyrosine kinase, in patients who had CML in blast crisis and in patients with ALL who had the Ph chromosome.

METHODS

In this dose-escalating pilot study, 58 patients were treated with STI571; 38 patients had a myeloid blast crisis and 20 had ALL or a lymphoid blast crisis. Treatment was given orally at daily doses ranging from 300 to 1000 mg.

RESULTS

Responses occurred in 21 of 38 patients (55 percent) with a myeloid-blast-crisis phenotype; 4 of these 21 patients had a complete hematologic response. Of 20 patients with a lymphoid blast crisis or ALL, 14 (70 percent) had a response, including 4 who had complete responses. Seven patients with a myeloid blast crisis continue to receive treatment and remain in remission from 101 to 349 days after starting the treatment. All but one patient with a lymphoid blast crisis or ALL has relapsed. The most frequent adverse effects were nausea, vomiting, edema, thrombocytopenia, and neutropenia.

CONCLUSIONS

The BCR-ABL tyrosine kinase inhibitor STI571 is well tolerated and has substantial activity in the blast crises of CML and in Ph-positive ALL.

In vitro cytotoxic effects of a tyrosine kinase inhibitor STI571 in combination with commonly used antileukemic agents

The BCR/ABL tyrosine kinase has been implicated in the pathogenesis of chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL). STI571 is a novel anticancer agent that selectively inhibits the BCR/ABL tyrosine kinase. The cytotoxic effects of STI571 were studied in combination with antileukemic agents against Ph(+) leukemia cell lines, KU812, K-562, TCC-S, and TCC-Y. The cells were exposed to STI571 and to other agents simultaneously for 5 or 7 days. Cell growth inhibition was determined by MTT assay. The cytotoxic effects in combinations at the inhibitory concentration of 80% level were evaluated by the isobologram. STI571 produced synergistic effects with recombinant and natural alpha-interferons in 2 of 3 and 3 of 3 cell lines, respectively. STI571 produced additive effects with hydroxyurea, cytarabine, homoharringtonine, doxorubicin, and etoposide in all 4 cell lines. STI571 with 4-hydroperoxy-cyclophosphamide, methotrexate, or vincristine produced additive, antagonistic, and synergistic effects in 3 of 4 cell lines, respectively. These findings suggest that the simultaneous administration of STI571 with other agents except methotrexate would be advantageous for cytotoxic effects against Ph(+) leukemias. Among them, the simultaneous administration of STI571 and alpha-interferons or vincristine would be highly effective against Ph(+) leukemias and these combinations would be worthy of clinical trials. In contrast, the simultaneous administration of STI571 with methotrexate would have little therapeutic efficacy. Although there are gaps between in vitro studies and clinical trials, the present findings provide useful information for the establishment of clinical protocols involving STI571. (Blood. 2001;97:1999-2007)

High-dose busulphan alone as cytoreduction before allogeneic or autologous stem cell transplantation for chronic myeloid leukaemia: a single-centre experience

Transplant-related morbidity and mortality remain a major problem following stem cell transplantation (SCT). The use of high-dose single-agent busulphan before allogeneic or autologous SCT may be a reasonable compromise between maintaining cytoreductive efficacy and minimizing toxicity in patients with chronic myeloid leukaemia (CML). Seventy patients with CML have received busulphan as the only cytoreductive therapy before SCT on 79 occasions. The probability of survival of the 14 allogeneic recipients (all of whom were undergoing a second transplant from the original donor) was 78% at 5 years. Sixty-five autologous SCT were performed in 56 patients, of whom 40 were in late chronic phase. The actuarial 3-year post-autograft survival was 54% for these 56 first autografts. For patients in chronic phase, the 3-year survival was 76% compared with 30% at 2 years for those with advanced phase disease. Busulphan therapy was well tolerated, and except for mild mucositis little toxicity was experienced. None of these patients developed hepatic veno-occlusive disease (VOD). Nine patients (one allogeneic and eight autologous recipients) received several doses of an intravenous formulation of busulphan with very low toxicity. High-dose busulphan alone appears sufficient to provide adequate cytoreduction and immunosuppression in second allogeneic transplants and is also effective as cytoreduction before autologous SCT in patients with CML.

Effects of the Tyrosine Kinase Inhibitor AG957 and an Anti-Fas Receptor Antibody on CD34+ Chronic Myelogenous Leukemia Progenitor Cells

The hallmark of chronic myelogenous leukemia (CML) is the Philadelphia (Ph) chromosome that fuses genetic sequences of the BCR gene on chromosome 22 with c-ABL sequences translocated from chromosome 9. BCR/ABL fusion proteins have a dysregulated protein tyrosine kinase (PTK) activity exerting a key role in malignant transformation. Targeting the tyrosine kinase activity of BCR/ABL or using agents capable of triggering apoptosis might represent attractive therapeutic approaches for ex vivo purging. AG957, a member of the tyrphostin compounds, exerts a selective inhibition of p210BCR/ABLtyrosine phosphorylation. We report here that preincubation of CML or normal CD34+ cells with graded concentration of AG957 (1 to 100 μmol/L) resulted in a statistically significant, dose-dependent suppression of colony growth from multipotent, erythroid, and granulocyte-macrophage progenitors as well as the more primitive long-term culture-initiating cells (LTC-IC). However, AG957 doses causing 50% inhibition (ID50) of CML and normal progenitors were significantly different for multilineage colony-forming units (CFU-Mix; 12 v 64 μmol/L; P = .008), burst-forming unit-erythroid (BFU-E; 29 v 89 μmol/L;P = .004), colony-forming unit–granulocyte-macrophage (CFU-GM; 34 v 85 μmol/L; P = .004), and LTC-IC (43 v 181 μmol/L; P = .004). In 5 of 10 patients, analysis of BCR/ABL mRNA on single progenitors by reverse transcription-polymerase chain reaction showed that AG957 at 50 μmol/L significantly reduced the mean (±SD) percentage of BCR/ABL-positive progenitors (92% ± 10% v 33 ± 5%;P = .001). Because AG957 treatment resulted in significantly higher percentages of apoptotic cells (30% v9%) in the BCR/ABL-transfected 32DLG7 cells as compared with 32D-T2/93 cells (BCR/ABL-negative), we investigated the combined effects of AG957 with the anti-Fas receptor (Fas-R) monoclonal antibody CH11 that triggers apoptosis. As compared with AG957 alone, the sequential treatment of CML CD34+ cells with AG957 (1 μmol/L) and CH11 (1 μg/mL) increased CFU-Mix, BFU-E, and CFU-GM growth inhibition by 1.6-fold, 3-fold, and 4-fold, respectively. In contrast, the treatment of normal CD34+ cells with AG957 and CH11 failed to enhance AG957-induced colony growth inhibition. We conclude that (1) AG957 inhibits in a dose-dependent manner CML CD34-derived colony formation by both primitive LTC-IC as well as committed CFU-Mix, BFU-E, and CFU-GM; (2) this growth inhibition is associated with the selection of a substantial amount of BCR/ABL-negative progenitors; and (3) the antiproliferative effect of AG957 is dramatically increased by combining this compound with the anti–Fas-R antibody CH11. These data may have significant therapeutic applications.

Effects of the Tyrosine Kinase Inhibitor AG957 and an Anti-Fas Receptor Antibody on CD34+ Chronic Myelogenous Leukemia Progenitor Cells

The hallmark of chronic myelogenous leukemia (CML) is the Philadelphia (Ph) chromosome that fuses genetic sequences of the BCR gene on chromosome 22 with c-ABL sequences translocated from chromosome 9. BCR/ABL fusion proteins have a dysregulated protein tyrosine kinase (PTK) activity exerting a key role in malignant transformation. Targeting the tyrosine kinase activity of BCR/ABL or using agents capable of triggering apoptosis might represent attractive therapeutic approaches for ex vivo purging. AG957, a member of the tyrphostin compounds, exerts a selective inhibition of p210BCR/ABLtyrosine phosphorylation. We report here that preincubation of CML or normal CD34+ cells with graded concentration of AG957 (1 to 100 μmol/L) resulted in a statistically significant, dose-dependent suppression of colony growth from multipotent, erythroid, and granulocyte-macrophage progenitors as well as the more primitive long-term culture-initiating cells (LTC-IC). However, AG957 doses causing 50% inhibition (ID50) of CML and normal progenitors were significantly different for multilineage colony-forming units (CFU-Mix; 12 v 64 μmol/L; P = .008), burst-forming unit-erythroid (BFU-E; 29 v 89 μmol/L;P = .004), colony-forming unit–granulocyte-macrophage (CFU-GM; 34 v 85 μmol/L; P = .004), and LTC-IC (43 v 181 μmol/L; P = .004). In 5 of 10 patients, analysis of BCR/ABL mRNA on single progenitors by reverse transcription-polymerase chain reaction showed that AG957 at 50 μmol/L significantly reduced the mean (±SD) percentage of BCR/ABL-positive progenitors (92% ± 10% v 33 ± 5%;P = .001). Because AG957 treatment resulted in significantly higher percentages of apoptotic cells (30% v9%) in the BCR/ABL-transfected 32DLG7 cells as compared with 32D-T2/93 cells (BCR/ABL-negative), we investigated the combined effects of AG957 with the anti-Fas receptor (Fas-R) monoclonal antibody CH11 that triggers apoptosis. As compared with AG957 alone, the sequential treatment of CML CD34+ cells with AG957 (1 μmol/L) and CH11 (1 μg/mL) increased CFU-Mix, BFU-E, and CFU-GM growth inhibition by 1.6-fold, 3-fold, and 4-fold, respectively. In contrast, the treatment of normal CD34+ cells with AG957 and CH11 failed to enhance AG957-induced colony growth inhibition. We conclude that (1) AG957 inhibits in a dose-dependent manner CML CD34-derived colony formation by both primitive LTC-IC as well as committed CFU-Mix, BFU-E, and CFU-GM; (2) this growth inhibition is associated with the selection of a substantial amount of BCR/ABL-negative progenitors; and (3) the antiproliferative effect of AG957 is dramatically increased by combining this compound with the anti–Fas-R antibody CH11. These data may have significant therapeutic applications.

Abnormal patterns of immunoglobulin heavy chain gene DNA fingerprinting during chronic phase chronic myeloid leukemia

Using IgH DNA fingerprinting we have previously demonstrated clonal immunoglobulin heavy chain (IgH) gene rearrangements during chronic phase (CP) chronic myeloid leukemia (CML) in patients destined to develop lymphoid blast crisis (L-BC). In view of this we decided to follow a cohort of CP CML patients to determine the frequency with which abnormal IgH fingerprints are found and their relationship, if any, to treatment regimen. Thirty three, initially CP, CML patients were studied on 111 occasions over a 16 month period using consensus PCR amplification of the third complementarity determining region (CDR3) of the IgH gene and high resolution polyacrylamide gel electrophoresis (IgH DNA fingerprinting). Of these 33 patients, thirteen received interferon-alpha (IFN) containing regimens and 15 non-IFN containing regimens throughout the study period. Five patients received variable therapy. During the period of observation 7 patients experienced disease progression: 5 accelerated phase, I L-BC and I myeloid blast crisis (M-BC). Abnormal IgH fingerprints were seen in 29 of the 111 (26%) specimens analysed. The 28 patients who received uniform therapy (IFN or non-IFN) over the 16 months were classified as "normal" (n = 18, normal pattern on all occasions) or "abnormal" (n = 10, abnormal on 1 or more occasions). Analysis by patient group (normal vs abnormal) showed that fingerprint abnormalities were associated with an elevated peripheral blood lymphocyte count (p = 0.0001) but not with changes in the total white cell count. Comparison of the IFN vs. non-IFN groups showed the former all had normal patterns whereas 10 of 15 non-IFN therapy patients were abnormal (p = 0.00023). The peripheral blood lymphocyte counts in the normal vs abnormal patients within the non-IFN group were not significantly different. The patient who developed L-BC demonstrated a persistent IgH fingerprint pattern abnormality from 7 months prior to the diagnosis of L-BC. The M-BC patient had a normal pattern at all times. We conclude that: (1) abnormal IgH fingerprints are found in a significant number of CP CML patients; (2) in this cohort the use of IFN was associated with normal CP CML IgH fingerprints, and (3) detection of abnormal IgH fingerprints may be highly predictive for the lineage of impending blast crisis.

Unrelated donor marrow transplantation for chronic myelogenous leukaemia

Between January 1989 and July 1995 the search for an unrelated donor (UD) was started for 379 consecutive Italian patients with Philadelphia positive (Ph+) chronic myelogenous leukaemia (CML). 89 (23%) were transplanted. The overall probability of transplant before and after December 1991 was 16% and 49%, respectively (P=0.0001), and average interval between search activation and graft was 23 months and 13 months, respectively (P=0.0001). Disease-free survival (DFS) following 60 consecutive transplants performed before February 1996 was 41.5% at 48 months and was 64% for patients grafted after January 1993. In univariate analysis, five variables had a favourable effect on DFS: year of bone marrow transplantation (BMT) after 1993 (P=0.0002), HLA-DRB1 donor/recipient (D/R) match (P=0.0006), total body irradiation (TBI) containing regimen (P=0.0006), graft-versus-host disease (GvHD) prophylaxis including 'early' cyclosporin before the transplant, and a marrow cell dose > 3 x 10(8)/kg of recipient body weight (P=0.04). Multivariate analysis confirmed that HLA identity (P=0.006), TBI-containing regimen (P=0.0001) and 'early cyclosporin' (P=0.04) were associated with higher DFS. Transplant-related mortality (TRM) was 67% in patients grafted before January 1993 and 30% in patients grafted subsequently (P=0.002). Multivariate analysis confirmed DRB1 identity (P=0.03) and TBI-containing regimen (P=0.0005) to be independent factors predictive of low TRM. This suggests that the outcome of patients transplanted from an HLA DRB1 matched donor, after a TBI-containing preparative regimen, is similar to results recently reported in patients transplanted from geno-identical siblings. These results indicate that the search should be initiated at diagnosis for patients < 45 years of age and UD BMT should be considered early in the disease course for those with an available DRB1-matched unrelated donor.

Autografting as first line treatment for chronic myeloid leukaemia

Interest in autografting for chronic myeloid leukaemia and its clinical relevance has revived in recent years. This followed observations that with various chemotherapeutic regimens it was possible to achieve, temporarily at least, peripheral blood and bone marrow that were Philadelphia negative. Bone marrow or peripheral blood progenitor cells could then be harvested and reinfused following a high dose procedure, hopefully eliminating any residual disease, and resulting in prolonged disease free survival. This ideal has not yet been successfully achieved with current strategies. Recent results indicate that eliminating residual disease with current chemotherapy is not normally achievable. The use of more sensitive technologies such as polymerase chain reaction has revealed persistent disease in most if not all apparently Philadelphia negative cases. This is confirmed by results where disease relapse occurs following transplant in these cases. Despite this, clinically relevant remissions are obtained and further trials are indicated. In this review present treatment is discussed and future strategies, using novel techniques as an adjunct to current treatment, are proposed that might improve on present results or even lead to the elusive goal of cure.

The Tyrosine Kinase Inhibitor CGP57148B Selectively Inhibits the Growth of BCR-ABL–Positive Cells

The Philadelphia chromosome found in virtually all cases of chronic myeloid leukemia (CML) and in about one third of the cases of adult acute lymphoblastic leukemia is formed by a reciprocal translocation between chromosomes 9 and 22 that results in the fusion of BCR and ABL genetic sequences. This BCR-ABL hybrid gene codes for a fusion protein with deregulated tyrosine kinase activity that can apparently cause malignant transformation. CGP57148B, a 2-phenylaminopyrimidine derivative, has been shown to selectively inhibit the tyrosine kinase of ABL and BCR-ABL. We report here that this compound selectively suppresses the growth of colony-forming unit–granulocyte/macrophage (CFU-GM) and burst-forming unit–erythroid derived from CML over a 2-logarithmic dose range with a maximal differential effect at 1.0 μmol/L. However, almost all CML colonies that grow in the presence of 1.0 μmol/L CGP57148B are BCR-ABL–positive, which may reflect the fact that residual normal clonogenic myeloid precursors are infrequent in most patients with CML. We also studied the effects of CGP57148B on hematopoietic cell lines. Proliferation was suppressed in most of the BCR-ABL–positive lines; all five BCR-ABL–negative lines were unaffected. We conclude that this new agent may have significant therapeutic applications.

Quality of life in young patients with chronic myelocytic leukaemia during intensive treatment including interferon

The aim of this study was to evaluate to what extent the quality of life (QOL) of young patients with chronic myelocytic leukemia (CML) was affected by treatment with interferon (IF) and intensive chemotherapy. In a main study performed by The Swedish CML Group, aiming at reduction of the malignant pH+ cell clone by treatment with hydroxyurea and IF followed by ABMT, QOL was evaluated with VAS scales and the Life Ingredient Profile in 44% of the patients. The intensive treatment did not lead to intolerable suffering or protracted reduction in QOL. However, 80% of the patients were on sick leave during the first year of treatment.

Myelodysplasia and the leukemias

The armistice after World War II marked the beginning of an era that was to last to the end of the present century. It was an era in which many changes in medicine and nursing combined to alter the entire philosophy of managing malignant disease. More specifically, the fluid-phase tumors, which comprise myelodysplasia and the leukemias, were singled out for special attention. First there was the ease with which blood and bone marrow could be sampled, making serial investigations simple and practical. Second, cytotoxic drugs became available ranging from nitrogen mustard through cytosine arabinoside, the anthracycline antibiotics, and the epi-podophyllotoxins. Although cytomorphology of the hematopoietic tissue had been exquisitely defined with the use of Romanowsky stains coupled with electron microscopy, the diagnosis of leukemia was, before 1945, a death sentence for want of effective therapy. This changed dramatically with the introduction of the folate antagonists, and progress was unremitting as the range of new products expanded. Suddenly responses could be obtained with single agents, and fairly rapidly combinations were developed for cumulative antitumor effect. Many agents had undesirable toxicity among different organs. Although slightly different for myeloblastic or lymphoblastic variants, this approach produced apparent disease eradication. The concept of complete remission, both clinical and hematologic, was born. Some of our early enthusiasm has had to be tempered with the somber appreciation that not all patients can improve and many others experience relapses. Where then do we stand? Leukemic cells themselves seldom kill. It is the relentless and uncontrolled expansion of a neoplastic clone that leads to bone marrow failure, albeit at different rates in the various subtypes. In the acute forms, the common presentation remains symptomatic anemia, neutropenic sepsis, and thrombocytopenic bleeding. Differentiation from marrow aplasia may not be possible at first on clinical grounds, although bone tenderness, gingival hypertrophy, and skin infiltration are among the general useful differential signs. Findings in the circulation and the marrow are of cardinal importance in diagnosis; they provide the basis for classification. Improved accuracy has followed the introduction of cytochemical stains, and a widening range of monoclonal antibodies, and greater recourse to karyotyping, have enhanced diagnostic acumen. Treatment decisions rest on many variables or prognostic factors that include age, performance status, comorbidity, and disease category, with an ever increasing regard for the part played by cellular and molecular genetics. Despite skillful utilization of this wealth of information for optimal management, outcome often leaves much to be desired. Myelodysplasia encompasses a number of different syndromes in which the refractory anemias are indolent, whereas those with excess blasts progress toward overt leukemia. Considerable judgment is necessary in selecting patients for whom supportive therapy alone is appropriate and recognizing others, up to one third of patients for whom use growth factors that include erythropoietin, granulocyte or granulocyte monocyte-colony stimulating factors, and thrombopoietin can be justified. The often unfavorable result has been a stimulus to current investigations that examine the value of intensive chemotherapy or the more innovative bone marrow transplantation and its peripheral blood equivalent. Autografting is a newer alternative that does not have proved potential. Acute leukemia, whether myeloblastic or lymphoblastic, has been managed with mixed success. Remission rates have steadily increased and, notably among children, moved toward 100% in certain groupings. The downside of nonspecific drug regimens is that some patients simply may not respond, whereas others experience remissions and then relapses. (ABSTRACT TRUNCATED)

Treatment of chronic myeloid leukaemia: some topical questions

The treatment of chronic myeloid leukaemia has become extremely complex in recent years. Busulphan has been displaced by hydroxyurea where rapid control of the leukocyte count is required. It is generally accepted that interferon-alpha (IFN-alpha) prolongs life for those who achieve a major or complete cytogenetic response and it may also prolong life for those who achieve only a haematological response. Thus routinely most newly diagnosed patients are started on treatment with IFN-alpha alone or in combination with other agents and this agent is continued if possible for 2 or more years. Because allografting is the only way of curing patients with CML, those under the age of 50 or 60 years who have HLA-identical siblings should be offered treatment by allogeneic haemopoietic stem cell transplantation; however, the risks of morbidity and mortality remain appreciable. Transplants with stem cells from phenotypically HLA-matched donors should also be considered for younger patients. The role of autografting is not yet clearly established; a series of controlled studies comparing autografting with IFN-alpha have therefore been activated. Because patients usually retain in their blood and marrow substantial numbers of Ph-negative stem cells a variety of methods designed to favour collection in vivo or isolation in vitro of Ph-negative stem cells are currently under investigation. To integrate these different approaches to treating patients with CML in chronic phase a variety of algorithms or flow charts have been proposed but many of the criteria on which the recommended treatment decisions are based remain controversial or ill-defined.

Autografting for chronic myeloid leukaemia

For most chronic myeloid leukaemia (CML) patients the option of a potentially 'curative' allogeneic stem cell transplant is not available because of age or lack of donor. Interferon alpha appears to extend survival when used in the chronic phase of the disease but probably does not produce long-term disease-free survivors. Autografting is being actively explored as a therapeutic option which may improve on the survival data seen with interferon and numerous different autografting methodologies are being investigated. While it seems reasonable to hope that a suitably robust and safe approach to autografting may improve survival it is unlikely with current technology that long-term disease-free survival will be achieved. To date no compelling trial data are available to confirm the efficacy of autografting but large prospective randomized studies are underway to investigate whether autografting can indeed extend survival for CML patients who do not have the option of an allograft.