Marrow transplantation for the treatment of chronic myelogenous leukemia

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.

Biphenotypic blast crisis of chronic myelogenous leukemia: abnormalities of p53 and retinoblastoma genes

The molecular mechanisms responsible for progression of chronic myelogenous leukemia (CML) to blast crisis have not been well defined. Blast crisis may be partially related to inactivation of tumor suppressor genes/such as p53 or retinoblastoma (Rb) gene. There is evidence for an association of blast cell phenotypes in CML with alterations of these genes: a strong association of myeloid phenotypes with abnormalities of the p53 gene and a weaker association of lymphoid phenotypes with abnormalities of the Rb system. We found a marked decrease in Rb gene product and rearrangements of the p53 gene simultaneously in two cases of biphenotypic blast crisis of CML (myeloid and B-lymphoid). These results support the association of blast cell phenotypes with alterations in tumor suppressor genes in CML blast crisis.

Marrow Transplantation for Chronic Myeloid Leukemia: The Influence of Plasma Busulfan Levels on the Outcome of Transplantation

The influence of busulfan (BU) plasma concentration on outcome of transplantation from HLA identical family members for the treatment of chronic myelogenous leukemia (CML) was examined in 45 patients transplanted in chronic phase (CP) (n = 39) or accelerated phase (AP) (n = 6). All patients received the same regimen of BU, 16 mg/kg orally and cyclophosphamide (CY), 120 mg/kg intravenously. Plasma concentrations of BU at steady state (CSSBU) during the dosing interval were measured for each patient. The mean CSSBU was 917 ng/mL (range, 642 to 1,749; median, 917; standard deviation, 213). Of patients with CSSBU below the median, seven (five of 18 in CP and two of four in AP) developed persistent cytogenetic relapse and three of these patients died. There were no relapses in patients with CSSBU above the median. The difference in the cumulative incidence of relapse between the two groups was statistically significant (P = .0003). CSSBU was the only statistically significant determinant of relapse in univariable or multivariable analysis. The 3-year survival estimates were 0.82 and 0.64 for patients with CSSBU above and below the median (P = .33). There was no statistically significant association of CSSBU with survival or nonrelapse mortality, although the power to detect a difference in survival between 0.82 and 0.64 was only 0.24, similarly CSSBU above the median was not associated with an increased risk of severe regimen-related toxicity. We conclude that low BU plasma levels are associated with an increased risk of relapse.

Cytogenetic and molecular genetic methods for diagnosis and treatment response in chronic granulocytic leukemia

Today, laboratory geneticists help clinical hematologists diagnose chronic granulocytic leukemia (CGL) and monitor the response of patients undergoing treatment. The most common genetic tests for CGL include quantitative cytogenetic studies, fluorescence in situ hybridization with probes for BCR and ABL, Southern blot analysis, and reverse transcriptase polymerase chain reaction. No single genetic testing procedure fulfills all the needs of clinicians who care for patients who have CGL. Thus, it has become important to use combinations of testing methods that are both accurate and cost-effective for any given clinical situation in the diagnosis and treatment of patients with CGL.

Allogeneic bone marrow transplant in pediatric patients with high-risk hematopoietic malignancies early in the course of their disease

PURPOSE

The purpose of this study was to investigate the role of bone marrow transplant (BMT) early in the course of disease for pediatric patients with high-risk leukemia using a preparatory regimen of fractionated total body irradiation (FTBI) and etoposide (VP-16).

PATIENTS AND METHODS

Those studied were 33 patients aged < or =18 years with either acute leukemia in first complete remission (CR) (n = 29) or chronic myelogenous leukemia (CML) in first chronic phase (n = 4) who received 1,320 cGy FTBI followed by high-dose VP-16 (60 mg/kg) as a preparatory regimen for BMT from matched sibling donors. Patients with acute leukemia included 18 with acute nonlymphocytic leukemia (ANLL), one with biphenotypic acute leukemia (BAL), and 10 with selected "high-risk" acute lymphocytic leukemia (ALL). Patients with ALL were selected for a high risk for recurrence: those who failed standard remission induction chemotherapy, had a t(9;22) or t(4;11) chromosomal translocation, or had certain clinical high-risk features.

RESULTS

At the time of analysis, 28 patients are alive, all of them in continued complete remission for 1.1-7.8 years (median, 5.3 years; mean, 4.9 years). The Kaplan-Meier projected event-free survival (EFS) is 84.5% at 7 years, and the actuarial recurrence hazard is 6.5%. All surviving patients have a performance status of >80%.

CONCLUSION

This result of early BMT in a two-institution study of pediatric patients with hematopoietic malignancies suggests that (a) matched sibling allogeneic BMT after conditioning with FTBI and high-dose VP-16 is an excellent treatment for pediatric patients with high-risk leukemia, and (b) children may have a better prognosis than adults treated with allogeneic BMT. Larger multiinstitutional cooperative trials for pediatric patients are needed to confirm this result.

Serum levels of cytokines and secondary messages after T-cell-depleted and non-T-cell-depleted bone marrow transplantation: influence of conditioning and hematopoietic reconstitution

Cytokines are increasingly recognized as important mediators of graft-versus-host disease (GVHD). Measurements of cytokine serum levels in patients with GVHD, and successful prevention and treatment of the disease with the use of cytokine antagonists to either the cytokine or its receptor, are only two of several factors demonstrating the involvement of cytokines in GVHD. To further investigate the role of cytokines in the pathomechanism of acute GVHD, we investigated endogenous serum levels of various cytokines and dependent molecules in sera of 14 patients after T-cell-depleted (TCD) bone marrow transplantation (BMT) and compared the results with those of 12 patients undergoing non-TCD BMT. The effect of various conditioning regimens and of hematopoietic reconstitution on cytokine serum levels was analyzed in detail in these cohorts of patients by measuring interferon (IFN)-gamma, IFN-alpha, tumor necrosis factor-alpha, interleukin-6, neopterin, and beta2-microglobulin. The analyses showed that an increase in IFN-gamma and neopterin serum levels was a specific feature of cyclophosphamide administration and was not observed after other cytostatic drugs or total body irradiation, and that an increase in IFN-gamma, neopterin, beta2-microglobulin, and IFN-alpha release depends on the presence of T cells in the graft. We conclude that significant cytokine serum alterations were noted after TCD BMT as compared with after non-TCD BMT. These alterations, besides depletion of cytotoxic effector cells, might be involved in preventing GVHD after TCD BMT. In addition, more attention should be devoted to the cytokine release-inducing capacity of the conditioning regimen, because such a release might influence the occurrence of transplant-related complications after BMT.

Intensive remission induction therapy for chronic myeloid leukemia in blast phase with a goal of post-remission bone marrow transplant--a pilot study

An intensive protocol utilizing mitoxantrone, high-dose cytarabine, vincristine, etoposide and methylprednisolone as induction therapy for chronic myeloid leukemia in blast transformation is described. Fourteen patients were treated, with a remission/second chronic phase achieved in 64%. None of the 3 patients older than 50 yr responded. Complete hematological responses were seen in 9 of the 11 younger patients, 4 of whom also became BCR-ABL negative by Southern Blot analysis. Four patients went on to allogeneic bone marrow transplant. Median remission durations were 4.5 (1-5) and 8.5 (5-16) months in the non-transplanted and transplanted cohorts, respectively. Median survival is 1.5 (0.5-3), 9.5 (7-14) and 17 (14-61+) months in the non-responding, responding non-transplanted and transplanted cohorts, respectively. Toxicity, particularly gastrointestinal, was significant. This represents an aggressive protocol that should be reserved for patients who are potential transplant candidates.

Chronic myelogenous leukemia: a review

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative disorder with an initially chronic course lasting for 3-5 years. It eventually transforms into accelerated and blastic phases, which are generally fatal. CML was one of the first diseases in which a specific chromosomal abnormality was identified, a t(9;22)(q34;q11) or Philadelphia chromosome. CML had been traditionally treated with conventional chemotherapy with hydroxyurea or busulfan. Although these agents can achieve hematologic remissions in most patients, no evidence of sustained disappearance of the chromosomal abnormality was evident. Interferon alpha (IFN-alpha) has been able to achieve hematologic and cytogenic remissions in a significant number of patients, and recent studies show a survival advantage for patients treated with IFN-alpha compared with those treated with conventional chemotherapy. The results of these studies are discussed, and the reasons for discordance among different investigators analyzed in this review. Allogeneic bone marrow transplantation (BMT) may be curative in some patients with CML. The benefits and limitations of this approach in the treatment of CML are also discussed and the results of different alternatives compared. Other alternatives of therapy, including newer chemotherapeutic agents, combinations of IFN-alpha with other agents, and autologous BMT, are presented. The availability of very sensitive techniques for detection of the Philadelphia chromosome at the molecular level has allowed the detection of minimal residual disease. The information available on these measurements is also analyzed. Finally, we discuss the alternatives for patients with accelerated and blastic phase CML, as well as the clinical characteristics and prognosis for patients with Philadelphia-chromosome-negative CML.

Result of interferon-alpha therapy in patients with chronic myelogenous leukemia 60 years of age and older

PURPOSE

To determine the response rate to interferon-alpha (IFN-alpha) in patients with chronic myelogenous leukemia (CML) aged 60 years and older.

PATIENTS AND METHODS

Patients with CML aged 60 years and older included in all protocols with INF-alpha therapy for chronic phase CML at the M.D. Anderson Cancer Center were analyzed. They were treated with human leukocyte or recombinant human IFN-alpha 5x10(6) U/m2 daily alone or in combination with hydroxyurea or IFN gamma. The clinical characteristics of the patients were analyzed and their hematologic and cytogenetic responses to IFN-alpha and survival from the initiation of therapy were determined. Results were compared with those of younger patients treated in the same protocols. Treatment-related toxicity was also analyzed.

RESULTS

Thirty-five of 274 (13%) patients included in trials of IFN-alpha-based regimens for CML were 60 years and older. Older patients had a higher percentage of bone marrow blasts (P = 0.04) and basophils (P = 0.09) than younger patients. Sixty-nine percent achieved a complete hematologic remission with IFN-alpha therapy, and 51% had a cytogenetic response, which was major in 26% and complete (Philadelphia chromosome-positive cells = 0%) in 20%, Their median survival was 64 months, and the estimated 5-year survival rate was 62%. These results were not different from those in younger patients. Twenty-two patients (63%) had at least grade 2 toxicity requiring dose adjustment. The most frequent side effects were neurotoxicity in 31% and chronic fatigue in 29%.

CONCLUSIONS

Patients with CML 60 years of age and older respond well to IFN-alpha therapy, but experience more toxicity. This therapy should be considered for these patients if they are otherwise in good condition, with careful attention to IFN-alpha toxicity and its management.

Donor leukocyte infusions in the treatment of chronic myeloid leukemia in relapse post bone marrow transplantation

A 25-yr-old Caucasian man presented in 1988 with Philadelphia chromosome (Ph) negative, bcr-abl rearranged, chronic phase chronic myeloid leukemia (CML). He was treated with human leukocyte antigen matched sibling allogeneic bone marrow transplantation but relapsed 5 yrs later. At this time he was given donor leukocyte infusions from the original bone marrow donor, seeking an immune anti-leukemic effect. This treatment induced graft versus host disease and severe bone marrow aplasia, requiring immunosuppression and repeat donor marrow infusion (without prior conditioning). Graft versus host disease was controlled and full donor hematopoiesis was restored, resulting in complete eradication of the leukemic clone at a molecular level. The patient remains in complete clinical and molecular remission and off all immunosuppression 24 mths later. This emphasizes a potentially powerful graft versus leukemia effect in CML.

Value of PCR analysis for long term survivors after allogeneic bone marrow transplant for chronic myelogenous leukemia: a comparative study

At present, allogeneic bone marrow transplantation (BMT) seems to be the only curative treatment for patients with chronic myeloid leukemia (CML). The mechanisms of this therapeutic approach probably include anti-leukemic immune response or "graft-versus-leukemia" (GVL) reaction against leukemic cell clones, since even aggressive chemotherapy is not sufficient per se to cure this type of disease. In many patients, allogeneic BMT results in the disappearance of the Ph chromosome; this negativity does not exclude the presence of residual leukemic cells since sensitivity of cytogenetic analysis is low. The chimeric BCR-ABL gene in CML is a tumor-specific marker that is well suited to allowing detection of low numbers of residual leukemic cells through the extremely sensitive detection method of polymerase chain reaction (PCR). Using this method, 1 leukemic cell in 10(5) or 10(6) normal cells can be detected. Many studies have evaluated the clinical significance and predictive value of BCR-ABL gene rearrangement detected by PCR assay after BMT, most often on heterogeneous populations. Results from such studies have been conflicting. We have conducted a review of the literature, focussing on long-term survivors (> 3 years from BMT) of CML to determine the value of PCR in such patients (n = 183). With the consideration that such a population is obviously heterogenous, long-term PCR negativity strongly correlated with achieving a cure since no patient relapsed in this population (n = 117). Among the PCR positive patients (n = 66), only 5 (8%) relapsed, suggesting a poor prognostic value for a PCR+ test > 36 months post-transplant. Besides the potential clinical value of these data, they contribute to the understanding of the biology of the disease and may suggest a crucial role for the long term GVL effect of marrow transplantation.

Improved survival of patients with chronic myelogenous leukemia undergoing allogeneic bone marrow transplantation

A total of 28 patients with chronic myelogenous leukemia (CML) in chronic phase (CP) received bone marrow allografts from HLA-matched siblings at the University of Florida between August 1984-July 1992. The present study compares the disease-free survival (DFS) for those patients who were transplanted before or after August 1988 using the same conditioning regimen. The analysis shows significant difference in 3-year DFS for those patients transplanted post- vs. pre-August 1988 (69.6% vs. 20%, respectively; P = 0.006). A decrease in pneumonitis due to different etiologies from pre-August 1988 (6/13, 46%) to post-August 1988 (1/15, 7%) was statistically significant (P = 0.029). A decrease, although statistically insignificant, in the overall incidence and severity of acute and chronic graft vs. host disease (GVHD) after August 1988 was also noticed. This study indicates significantly improved outcome for patients with CML in CP who have been treated in the University of Florida after August 1988. Better supportive care and prophylaxis for GVHD most likely contributed to such improvement.

Roquinimex-induced graft-versus-host reaction after autologous bone marrow transplantation

BACKGROUND

Roquinimex is being used for posttransplantation immunotherapy of autologous bone marrow transplantation for acute and chronic myelogenous leukemia. This immunotherapeutic agent is a cytokine inducer and may induce an autologous graft-versus-host (GVH) and graft-versus-tumor reactions.

OBJECTIVE

Our purpose was to examine patients undergoing this immunotherapy for clinical signs and symptoms of acute GVH reactions and to correlate these symptoms with their clinical outcome.

METHODS

We studied eight patients receiving requinimex therapy.

RESULTS

We found autologous GVH reactions in three of eight patients (38%) treated with this immunotherapy. Their disease was manifested by localized or widespread violaceous papules that on histologic evaluation were compatible with a grade II GVH reaction. The acute cutaneous GVH reaction was associated with eccrine sweat gland necrosis, a dermatologic toxicity usually associated with chemotherapy.

CONCLUSION

Long-term studies of larger numbers of patients treated with this immunotherapy will determine whether these GVH reactions confer significant, sustained, antitumor effects.

Interferon-alpha therapy for chronic myelogenous leukemia

PURPOSE

To provide a status report on the use of interferon (IFN)-alpha in patients with chronic myelogenous leukemia (CML).

DATA SOURCES

Data on IFN-alpha therapy for CML collected from published articles identified in a MEDLINE computer search.

RESULTS

Previously untreated patients with low-risk factors and early-stage disease consistently had the best results in clinical trials. A dose response was seen, with patients treated with dosages of 5 million units (MU)/m2 per day showing the greatest incidence of cytogenetic remissions. In addition, randomized trials showed a survival advantage for IFN-alpha-treated patients. In studies comparing IFN-alpha therapy to chemotherapy, IFN-alpha produced significantly more major and durable cytogenetic responses than chemotherapy did. In studies combining IFN-alpha and chemotherapy, patients had significantly more cytogenetic responses, although more patient accrual and follow-up data are needed to offer conclusive statements concerning durability of response. IFN-alpha also showed activity in maintaining remissions after both chemotherapy and bone marrow transplantation.

CONCLUSIONS

IFN-alpha has significant activity in patients with CML, with best results at dosages of 5 MU/m2 per day. At these dosages, in patients with early-stage, Philadelphia+ CML, hematologic response rates of 70% to 80% and cytogenetic response rates of 50% (approximately 20% of which were complete) are seen. One randomized trial shows a survival advantage with cytogenetic response in IFN-alpha-treated patients, and this advantage appears to be unrelated to the degree of that response. These questions remain under study.

Circulating colony-forming units of granulocytes/monocytes in patients with chronic myeloid leukemia before and during busulfan treatment

The number of colony-forming units of granulocytes/monocytes (CFU-GM) in the peripheral blood of 7 patients with chronic myeloid leukemia (CML) in chronic phase (CP) receiving standard doses of busulfan (BSF, 0.1-0.2 mg/kg/day p.o.) was compared to that found in 8 patients with CML in CP not previously treated in order to establish if non-myeloablative chemotherapy mobilizes committed granulomonocytic progenitor cells into the circulation. The number (mean +/- SEM) of spontaneous CFU-GM in untreated patients was similar to that recorded in 10 sex- and age-matched controls, 2.6 +/- 1.9 and 3.5 +/- 2.1, respectively. BSF-treated patients showed significantly more spontaneous CFU-GM (13.9 +/- 7.5) than controls and untreated patients. Addition of recombinant human granulocyte/monocyte colony-stimulating factor to cultures promoted colony growth in controls but not in untreated and BSF-treated patients. These data seemingly indicate that: 1) administration of standard non-myeloablative doses of BSF to patients with CML in CP mobilizes CFU-GM into the circulation and 2) BSF therapy selects a granulomonocytic colony-forming progenitor cell population with increased autonomous growth potential. These findings may contribute to the understanding of the therapeutic role of BSF in CML.

Transfer of the HSV-tk gene into donor peripheral blood lymphocytes for in vivo modulation of donor anti-tumor immunity after allogeneic bone marrow transplantation

The infusion of donor lymphocytes after allogeneic bone marrow transplantation is a promising therapeutic tool for achieving a graft versus leukemia (GvL) effect in case of leukemic relapse (1-7), and for the treatment of other complications related to the severe immunosuppressive status of transplanted patients, such as Epstein Barr virus-induced lymphoproliferative disorders (EBV-BLPD) (8) or reactivation of CMV infection (9). Although the delay in the administration of T lymphocytes is expected to reduce the risk of severe GvHD, this risk is still present at higher doses of donor T-cells. The transfer of a suicide gene into donor lymphocytes could allow the in vivo selective elimination of cells responsible for severe GvHD. Additionally, under appropriate conditions, it may allow in vivo modulation of donor anti-tumor responses, and to separate GvL from GvHD. Finally, crucial questions concerning survival and function of donor lymphocytes could be answered by their gene marking. Previous studies documented that T lymphocytes are suitable targets for gene transfer through retroviral vectors (10, 11). This protocol has been designed to evaluate in the contest of allogeneic BMT: 1--the safety of increasing doses of donor lymphocytes transduced with a suicide retroviral vector; 2--the efficacy in terms of survival and immunologic potential of donor lymphocytes after in vitro activation, gene transduction, and immunoselection; 3--the possibility of in vivo down regulation of GvHD by the administration of ganciclovir to patients treated by tk-transduced donor lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon and chronic myelogenous leukaemia

Interferon (IFN) is widely employed in the therapy of chronic myelogenous leukaemia because of its ability to exert the antiproliferative activity on leukaemic haematopoietic progenitors and for the expression for IFN-alpha receptors by peripheral blood leukaemic cell surfaces. There is no difference between recombinant IFN alpha 2b and alpha 2a regarding their efficacy in the treatment of Ph-positive CML patients. Either no randomized studies or the randomized ones show a superior effectiveness of IFN given as single agent in the induction treatment to that one of chemotherapy regarding the complete cytogenic response percentage. The ability of IFN-gamma to induce the expression of adhesion molecules such LFA 1 and ICAM 1 on peripheral blood leukaemic cell surfaces may suggest its use in the induction therapy of CML patients. Other than, a superior effectiveness of combined therapy including interferon and chemotherapy agents compared to chemotherapy alone has also been found. Finally no large series of trials to study the IFN efficacy both as second line treatment and maintenance therapy have been carried out.

Case report of spontaneous remission of cytogenetic relapse of chronic myelogenous leukemia suggestive of progression to blast crisis after allogeneic bone marrow transplantation

Detection of the chronic myelogenous leukemia (CML)-related marker, the bcr/abl m-RNA transcript, in blood or bone marrow of patients with CML in hematologic remission after allogeneic bone marrow transplantation (allo-BMT) may be associated with the presence of minimal residual disease but does not uniformly predict hematologic relapse. In contrast, when there is cytogenetic reappearance of the Philadelphia (Ph1) translocation [t(9;22)(q34;q11)] along with additional cytogenetic abnormalities, especially more than 2 years after BMT, progression to hematologic relapse and acceleration of CML usually occur. An exception to this rule may be our patient, who was a 29-year old white woman diagnosed with Ph1-positive CML by cytogenetics. She was initially treated with hydroxyurea. An allo-BMT was performed 4 months after the diagnosis, while the patient was still in the first chronic phase of her disease, her HLA-identical brother serving as bone marrow (BM) donor. The conditioning regimen for BMT consisted of cytosine arabinoside, cyclophosphamide, total body irradiation, splenic irradiation, and intrathecal methotrexate. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin A and methotrexate. Her hospital course was unremarkable and without evidence of acute GVHD. Six months after transplantation, the patient had mild chronic GVHD and was treated with azathioprine and prednisone for 6 months. A year later, she recurred with mild chronic GVHD. She was treated with azathioprine alone for 5 months. Subsequently, she received cyclosporin A and prednisone for 8 months, with resolution of her symptoms. Serial BM cytogenetic studies showed normal male donor karyotypes 12 and 24 months after BMT. At 36, 42, and 50 months after BMT, reappearance of the Ph1 was noted along with some cells with additional cytogenetic abnormalities, including t(6;14)(p21;q32). The breakpoint involvement of 14q32, the heavy chain Ig locus, in the new clone may be indicative of B-lymphoid lineage-based evolution. The abnormal clones disappeared 56 months from BMT and remained absent through 69 months after BMT. The patient has remained in hematologic remission during her entire post-BMT course. Clinically, she continues to do well without immunosuppressants at presently 69 months after BMT. The reappearance of the Ph1 chromosome could be associated with the immunosuppressive therapy given for chronic GVHD. This case supports the concept that immunologic mechanisms may be important in the eradication of CML after allo-BMT, and even cytogenetic evidence of blast crisis CML may spontaneously remit after allo-BMT.

Mechanisms of cyclophosphamide resistance in a human myeloid leukemia cell line

The 4-hydroperoxycyclophosphamide (4HC)-resistant B5-180(3) subline of the cloned KBM-7/B5 cell line was developed as a model of induced cyclophosphamide resistance in human myeloid leukemia. Based on IC90 values, this subline was approximately 20-fold resistant to 4HC. Furthermore, it was significantly cross-resistant to phosphorodiamidic mustard (PM), whose cytotoxicity is independent of aldehyde dehydrogenase (ADH). Using alkaline elution we found that the resistant line had decreased initial levels of DNA interstrand cross-links (ISCs) following 4HC but not PM treatment. The resistant cells also appeared to remove ISCs from their DNA more rapidly than the parental cells. Our data therefore suggest that 4HC resistance in the B5-180(3) subline is multifactorial; ADH is an important mediator of its resistance to ISC induction by 4HC, while a second process, which may involve an increased ability to tolerate drug-induced DNA damage, appears to be important for its resistance to both 4HC and PM. The B5-180(3) cells were also cross-resistant to gamma-radiation (approximately 1.7-fold at a surviving fraction of 0.1); if generally applicable, such effects could have important clinical implications, since pretransplant total body irradiation is a major component of the eradication of leukemic cells.

Availability and appropriateness of allogeneic bone marrow transplantation for chronic myeloid leukemia in 10 countries

BACKGROUND

Allogeneic bone marrow transplantation, a sophisticated and expensive procedure, is the only curative therapy for chronic myeloid leukemia (CML). We examined the availability and appropriateness of allogeneic bone marrow transplantation for CML in 10 economically advanced countries with diverse health care systems. For each country we obtained data on the likelihood of transplantation to treat CML in patients under the age of 55 years, the length of time from diagnosis to transplantation, and the stage of disease at the time of transplantation.

METHODS

Data were collected on 9873 allogeneic bone marrow transplantations performed at 208 centers in 10 countries from 1989 through 1991. Data were acquired from transplantation registries and by means of a mailed survey of all centers and teams that did not contribute data to registries. Data on the incidence of disease were drawn from national and regional cancer registries.

RESULTS

Among the 10 countries there was a twofold difference between the lowest and highest rates of transplantation to treat CML (0.26 to 0.54 per 100,000 population per year); Swedish patients were the most likely to receive a transplant, and German patients the least likely. The median length of time from diagnosis to transplantation ranged from 6.8 to 15.4 months. In all countries, most transplantations were performed in the chronic phase of the disease, but as many as a third of patients received transplants in the less favorable accelerated or blast phase. The values for the United States fell near the middle of those for the 10 countries on all measures.

CONCLUSIONS

Our findings challenge the assumption that the United States is unique in providing broad access to high-technology treatments. On no measure of the availability or appropriateness of transplantation for CML did it surpass the other nine countries studied.

Issues in the diagnosis and management of essential thrombocythemia

OBJECTIVE

To summarize the current trends in the diagnosis and management of essential thrombocythemia (ET) and to discuss the treatment of young and pregnant patients with ET.

DESIGN

We review our experiences in the diagnosis and management of ET.

MATERIAL AND METHODS

A definitive diagnosis of ET at initial examination is seldom possible because of the low incidences of associated clonal cytogenetic abnormalities and palpable splenomegaly. The criteria of the Polycythemia Vera Study Group for the diagnosis of ET are provided, as are the clinical and laboratory features that help to distinguish ET from reactive thrombocytosis.

RESULTS

Patients with ET have an almost normal life expectancy if thrombohemorrhagic complications are controlled. Although a previous history of thrombosis is an established risk factor for further episodes, the adverse effects of extreme thrombocytosis and age are less well defined. Determining which patients require therapy is controversial. The management of young or pregnant patients necessitates special considerations.

CONCLUSION

Until additional data become available, no strong recommendations can be given in support of or against specific therapy for asymptomatic young patients. We favor treatment in asymptomatic patients with cardiovascular risk factors but not in asymptomatic women who are pregnant or are of childbearing age.

Intensive conditioning regimen for bone marrow transplantation in children with high-risk haematological malignancies

Between September 1987 and May 1991, 21 children aged 10 months to 15 years (median 9 years) underwent bone marrow transplantation (BMT) for advanced haematological malignancies using a conditioning regimen consisting of total body irradiation (TBI), etoposide 1.8 g/m2 by continuous infusion, and cyclophosphamide 2 g/m2 on 3 consecutive days. The patients included 14 with acute lymphoblastic leukaemia (ALL), 1 with chronic myeloid leukaemia (CML), 1 with juvenile CML, 4 with non-Hodgkin's lymphoma and 1 with acute nonlymphocytic leukaemia. Eleven had an allogeneic BMT from an HLA-matched sibling, and 1 from an unrelated donor. Nine patients received 4-hydroperoxycyclophosphamide purged autologous marrow. Median time to myeloid engraftment (ANC > 500/microliters) was 19 days in allogeneic BMT patients and 28 days in autologous BMT patients (P < .01). Mucositis was the major regimen-related toxicity (RRT). GI toxicity in the form of diarrhoea affected ten patients and five had veno-occlusive disease of the liver. Two patients had mild bladder toxicity and one died of renal toxicity. There was no CNS or cardiac toxicity. There was no significant difference in the incidence of toxicity according to the type of BMT (autologous or allogeneic), total dose, or sequence of TBI. With a median follow-up of 44 months, ten patients are alive (6/12 allogeneic BMT patients and 4/9 autologous BMT patients). Of the 11 deaths, four were related to toxicity (2 aspergillus, 1 haemorrhage following liver biopsy, and 1 from haemolytic-uraemic syndrome), and 4/12 allogeneic and 4/9 autologous BMT patients died from relapsed disease. This conditioning regimen is well tolerated in children, demonstrating mild and reversible RRT.

Sequential cytogenetic study of patients after bone marrow transplantation

Thirty-one patients (19 males and 12 females; mean age 23.9 years, range 4-41 years) were treated with bone marrow transplantation (BMT) after intensive chemoradiotherapy. Their diagnoses were as follows: chronic myeloid leukemia (CML) in 13, acute myeloid leukemia (AML) in seven, acute lymphocytic leukemia (ALL) in six, myelodysplastic syndrome (MDS) in two, aplastic anemia (AA) in two, and Fanconi anemia (FA) in one. Allogeneic BMT was performed in 28 cases (17 donors were of like sex, 11 were of unlike sex), one patient received syngenic transplant, and one received transplant of cells obtained from an unrelated donor through a computerized international registry in London. Autologous BMT was performed in three patients. BM cells were analyzed cytogenetically at diagnosis, before and serially after BMT (three to nine times). Follow-up ranged from 2 to 55.5 months. Cytogenetic examination was a very useful method for monitoring posttransplantation course in patients with CML or in those who received BM cells of unlike sex. Results of concomitant cytogenetic examinations are reported in detail.

Bone marrow transplantation in leukemia

Bone marrow transplants are increasingly being used as treatment for leukemia. Several IBMTR studies have identified variables predicting outcome in allogeneic transplants. These studies have also identified factors like GVL that increase our understanding of leukemia treatment. Following the success of HLA-identical sibling transplants, allografts from related and unrelated donors are now performed frequently and achieve long-term LFS. The use of autologous transplants, with and without marrow treatment, is also increasing and continues to be investigated as an alternative therapy for leukemia.

Unresponsiveness of primitive chronic myeloid leukemia cells to macrophage inflammatory protein 1 alpha, an inhibitor of primitive normal hematopoietic cells

Most primitive hematopoietic cells appear to be normally quiescent in vivo, whereas their leukemic counterparts in patients with chronic myeloid leukemia (CML) are maintained in a state of rapid turnover. This difference is also seen in the long-term culture system, where control of primitive hematopoietic progenitor proliferation is mediated by interactions of these cells with marrow-derived mesenchymal cells of the fibroblast lineage. We now show that exogenous addition of macrophage inflammatory protein 1 alpha (MIP-1 alpha) to normal long-term cultures can reversibly and specifically block the activation of "primitive" (high proliferative potential), but not "mature" (lower proliferative potential), progenitors in the adherent layer of these cultures. Moreover, addition of MIP-1 beta after primitive-progenitor activation can prevent the subsequent return of these cells to a quiescent state a few days later as shown previously in similar experiments using antibodies to transforming growth factor beta. This suggests that the level of MIP-1 alpha (or a related MIP-1 alpha agonist) produced in LTCs, like the level of transforming growth factor beta, may be necessary, but is not on its own sufficient, to mediate the inhibitory activity of the regulatory cells in the adherent layer. Addition of MIP-1 alpha to similar long-term cultures containing normal marrow adherent layers but supporting exclusively neoplastic (CML) hematopoiesis did not block the cycling of primitive neoplastic progenitors. A defect in the responsiveness of CML cells to MIP-1 alpha (or a similarly acting chemokine) would explain their deregulated proliferative behavior in this model and, by extrapolation to the in vivo setting, suggests a molecular mechanism whereby the leukemic clone may become amplified at the stem-cell level. In addition, these findings suggest approaches to the therapy of CML, using inhibitors such as MIP-1 alpha for the protection of primitive normal cells.

Allogeneic bone marrow transplantation following busulfan-cyclophosphamide with or without etoposide conditioning regimen for patients with acute lymphoblastic leukaemia

We have investigated the feasibility and efficacy of administering a radiation-free preparative regimen in the setting of allogeneic bone marrow transplantation (BMT) in 40 consecutive patients with acute lymphoblastic leukaemia (ALL). Busulfan (4 mg/kg/d x 4 d) and cyclophosphamide (50 mg/kg/d x 4 d) (BuCy4) were given in 29 patients and 11 received busulfan (4 mg/kg/d x 4 d), etoposide (60 mg/kg) and cyclophosphamide (60 mg/kg/d x 2 d) (BuCy+VP - 16). Median age was 22 years (range 1-50); 11 patients were children < or = 15 years of age. All children and 20 adults were at high risk of relapse pretransplant. Nine adults and one child died from transplant-related toxicity. 11 patients relapsed at a median of 11 months post-transplant (range 2-27). The 3-year Kaplan-Meier estimated probability of relapse was 42.1% and found to be significantly lower in patients with chronic GVHD (P = 0.03). 19 patients are leukaemia-free survivors with a median follow-up of 33 months (range 7-59). The Kaplan-Meier actuarial probability of disease-free survival at 3 years was 43% for all patients. 63.6% for children versus 30.2% for adults (P = 0.24) and 51.6% for patients transplanted in first remission versus 30.2% for those transplanted in subsequent remissions (P = 0.20).

Chronic myelogenous leukemia: in search of the benign hematopoietic stem cell

Donor marrow transplantation can cure chronic myelogenous leukemia (CML). Unfortunately, the procedure is associated with severe complications and is limited to the minority of potential recipients with suitably matched donors. Autologous marrow transplantation using negative selection approaches such as incubation with gamma interferon (IFN-gamma) can produce cytogenetic and clinical remissions, but they are often associated with recurrent evidence of leukemia. A primitive progenitor population can be separated from normal human marrow on the basis of morphologic characteristics and cell surface antigen expression. Cell populations with similar morphologic and phenotypic characteristics obtained by positive selection from the marrow of patients with CML appear to be benign. Benign primitive and committed progenitors selected in this fashion can be expanded ex vivo when cultured in a "Transwell" system which physically separates hematopoietic cells from stromal feeder layers. Positive selection and ex vivo cultivation of benign progenitors from CML marrow may provide a source of hematopoietic stem cells suitable for autologous marrow transplantation. Autologous natural killer (NK) cells obtained from the peripheral blood of patients with CML are of benign origin and have antileukemia activity. Interleukin 2 (IL-2) activated autologous NK cells may be used in post-transplant cellular therapy to prevent recurrence of CML.

Autografting in chronic myelogenous leukemia followed by immunotherapy

Patients with chronic myelogenous leukemia (CML) can be cured with allogeneic bone marrow transplantation. Over the past decade, it has become clear that immunological mechanisms, in the form of graft-versus-leukemia, constitute an integral part of this therapy. Because of limitations imposed by a lack of suitable donors, age, and toxicity, only a minority of patients can be offered allogeneic bone marrow transplantation (BMT). Recently, attempts have been made to employ autologous bone marrow transplantation (ABMT) for the therapy of CML using a variety of pre- and post-transplantation manipulations. This report describes the rationale for an ongoing clinical trial using the immunomodulator roquinimex (Linomide), following autologous bone marrow transplantation, in an attempt to stimulate the immunological responses thought to be critical for successful therapy in CML.

Evaluating survival after allogeneic bone marrow transplant for chronic myeloid leukaemia in chronic phase: a comparison of transplant versus no-transplant in a cohort of 258 patients first seen in Italy between 1984 and 1986. Italian Cooperative Study Group on Chronic Myeloid Leukaemia

Information on the outcome of allogeneic bone marrow transplant (BMT) for chronic myeloid leukaemia (CML) was previously provided by BMT centres or registries. This report uses the data from another source, based on a cohort of 258 patients aged 50 or less who were first seen and recruited between 1984 and 1986 at 55 Italian hospitals. These patients were registered and followed for a prospective study of the course and prognosis of CML, without any obligations for treatment. All patients had Ph+ CML; 50 of them were transplanted in first chronic phase (CP), and 208 were not transplanted. Leukaemia-free survival at 8 years was 34% (95% CI 20-47%) for the transplant group versus zero in the non-transplant group. Overall survival at 8 years was 43% (95% CI 29-57%) for the transplant group versus 25% (95% CI 19-32%) in the non-transplant group (P = 0.24). The difference in overall survival between transplant and non-transplant was significant in patients less than 30 years old (P = 0.035), but not in patients aged 30-50 years (P = 0.439). This report points out that although freedom from leukaemia could be obtained only with BMT, a beneficial effect of BMT on overall survival could be detected only in a patients' subset, and that many hundreds of cases and a decade could be necessary to evaluate the effect on survival of new transplant policies.

Treatment of 11 patients with chronic myelogenous leukemia with interferon-alpha-2C and low-dose cytosine arabinoside

Patients with Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) and on interferon (IFN)-alpha-2c treatment for at least two months were entered in the present pilot study. IFN-alpha treatment was maintained identically and cytosine arabinoside (Ara-C) was added at monthly cycles of 10 mg/m2/day for ten days subcutaneously. In the case of a leukocyte nadir above 10 G/l, the Ara-C dose was increased to 20 mg/m2/day for 10 days per month. Ten of the eleven patients entered in this study were evaluable for toxicity and response. They received a total of 87 IFN-alpha/Ara-C cycles (3-14/patient). Five patients received 1-5 cycles with Ara-C dose intensification to 20 mg/m2/day. The following gastrointestinal and hematological toxicities were attributable to Ara-C, as they had not been observed in these patients during the preceding IFN-alpha monotherapy period. Gastrointestinal side effects consisted of nausea grade 1 (n = 5) and diarrhea grade 2 (n = 1). Hematotoxicity was observed in eight patients, grade 1 in five patients and grades 2, 3 and 4 in one of the patients each. Both episodes of grades 3 and 4 toxicity were seen during dose escalation to 20 mg/m2. Small cytogenetic responses (4-14%) were observed in 3 patients and a larger one (50%) in one patient, hematological improvement or stable disease in an additional three patients. These preliminary data suggest that the combination of IFN-alpha and low-dose Ara-C is active in inducing cytogenetic responses in CML patients at an acceptable rate of toxicity and therefore warrant further investigation.

Recurrence of Philadelphia chromosome-positive leukemia in donor cells after bone marrow transplantation for chronic granulocytic leukemia

Allogeneic bone marrow transplantation has been shown to be a very effective therapy for Chronic Granulocytic Leukemia with long term disease free survivals in excess of 60%. Relapse rates remain low at 15% following histocompatible sibling transplants and lower rates following matched unrelated donor grafts. Relapse rates however, are higher if BMT is carried out in transformation or blast crisis. Leukemic relapse in donor cells following transplantation for CGL is a rare event. The occurrence of donor leukemia however, may be under reported as accurate and sensitive investigation of the origin of relapsed leukemia following BMT requires DNA based technologies. A possible mechanism of donor leukemia in CGL is transfection of donor cells with the chimeric gene which is unique to this disease. It is possible that the malignant cells found in transformed or blast crisis of CGL may have a greater potential to transfect donor haematopoietic material. Careful evaluation of the incidence of donor leukemia using molecular biology methods may elucidate the frequency of this event following BMT for CGL.

Highly efficient elimination of Philadelphia leukemic cells by exposure to bcr/abl antisense oligodeoxynucleotides combined with mafosfamide

Synthetic oligodeoxynucleotides complementary to the break-point junction of bcr-abl transcripts selectively inhibit the proliferation of Philadelphia-positive leukemic cells, but residual leukemic cells persist in antisense oligodeoxynucleotides-treated cultures. Cyclophosphamide derivatives such as mafosfamide and 4-hydroperoxycyclophosphamide are used at high doses for purging of Philadelphia leukemic cells from marrows but such treatment can be associated with delayed engraftment and prolonged cytopenias. To develop a more effective procedure that might optimize the killing of leukemia cells and the sparing of normal hematopoietic progenitor cells, a 1:1 mixture of Philadelphia leukemic cells and normal bone marrow cells was exposed to a combination of a low dose of mafosfamide and bcr-abl antisense oligodeoxynucleotides and assayed for growth ability in clonogenic assays and in immunodeficient mice. Bcr-abl transcripts were not detected in residual colonies, and cytogenetic analysis of individual colonies revealed a normal karyotype. Normal but not leukemic hematopoietic colonies of human origin were also detected in marrows of immunodeficient mice 1 mo after injection of the treated cells. Our results indicate that a combination of a conventional chemotherapeutic agent and a tumor-specific antisense oligodeoxynucleotide is highly effective in killing leukemic cells and in sparing a much higher number of normal progenitor cells as compared with high-dose mafosfamide treatment. This offers the prospect of a novel and more selective ex vivo treatment of chronic myelogenous leukemia.

Clinical significance of bcr-abl gene rearrangement detected by the polymerase chain reaction after allogeneic bone marrow transplantation in chronic myelogenous leukemia

Although serial detection of bcr-abl positive cells by PCR appears able to identify distinct patient groups with different risks of relapse following BMT, there remain many unanswered questions regarding the clinical utility and biological significance of PCR detectable cells in this disease. Many of the studies summarized have conflicting results and the influence of various clinical parameters which are known to affect the risk of relapse post-BMT has not yet been consistently associated with the ability to detect bcr-abl positive cells by PCR. These clinical parameters include GVHD, T-cell depletion and intensity of immunosuppression following BMT. Prospective studies with larger patient numbers will be necessary to define the impact of these factors in PCR status and relapse. The answers to all these questions will increase our understanding of the biology of chronic myelogenous leukemia and help provide more effective therapies for the future.

Minimal residual disease after allogeneic bone marrow transplantation for chronic myeloid leukaemia in first chronic phase: correlations with acute graft-versus-host disease and relapse

We have studied 61 patients who underwent allogeneic bone marrow transplantation (BMT) for chronic myeloid leukaemia (CML) in first chronic phase. Minimal residual disease was detected by the amplification of the leukaemia-specific BCR-ABL fusion mRNA with the polymerase chain reaction (PCR) using a highly sensitive nested primer strategy. As a general pattern, patients often had detectable BCR-ABL (PCR positive) for up to 6 or 9 months post BMT after which time BCR-ABL became undetectable (PCR negative). The conversion from PCR positive to PCR negative was not associated with the time at which cyclosporin A treatment was stopped. Six patients (10%) have relapsed during the period of this study, two within 1 year and four more than 1 year after transplant. The relationship between PCR positivity more than 1 year post transplant and relapse was significant (P = 0.036) but 15 patients who were PCR positive beyond 1 year remain in complete clinical and cytogenetic remission. Thus late positivity identifies a group of patients at increased risk of relapse but is of little predictive value for individual patients. Of the four late relapses, two had been persistently PCR positive and two were initially PCR positive, converted to negative and subsequently to positive again. Although all relapses were preceded by PCR positivity, relapse may occur only 12 months after a PCR negative result. The proportion of patients PCR negative at 3/4 months after BMT was found to increase significantly with the severity of acute GVHD (P = 0.002) but no relationship was found between acute GVHD and subsequent PCR results. There was no clear association between severity of chronic GVHD and PCR result.

Increased risk of relapse in patients with chronic myelogenous leukemia given T-cell depleted marrow compared to methotrexate combined with cyclosporin or monotherapy for the prevention of graft-versus-host disease

Fifty-two patients with chronic myelogenous leukemia (CML) who underwent bone marrow transplantation (BMT) at Huddinge Hospital were analyzed retrospectively regarding type of graft-versus-host disease (GvHD) prophylaxis. With T-cell depletion (TCD) (n = 13) the incidence of grade II-IV acute GvHD was 8% compared to 27% among patients given short course methotrexate (MTX) + cyclosporin (CSA) (n = 23) (ns) and 60% in patients who received MTX or CSA alone (n = 16) (p = 0.006 vs TCD and 0.03 vs MTX + CSA). The incidence of chronic GvHD was 56%, 31% and 75%, in the three groups, respectively (p = 0.02 combination vs monotherapy). Probability of relapse differed significantly, with most relapses in the TCD group, 62% compared to 20% in the MTX + CSA group (p = 0.02) and no relapse in the monotherapy group (p = 0.01 TCD vs monotherapy). Patient survival at 6 years was 54%, 59% and 38%, in the three groups, respectively (ns). Relapse-free survival was 23% in the TCD group, 55% in the combination group (p = 0.06) and 38% in the monotherapy group (ns). We conclude that TCD in patients with CML is correlated with an increased risk of relapse and a tendency towards a decreased long-term relapse-free survival compared to patients receiving other kind of GvHD prophylaxis.