Frequency and clinical significance of BCR-ABL mutations in patients with chronic myeloid leukemia treated with imatinib mesylate.

Mutations of the BCR-ABL kinase domain are a common mechanism of resistance to imatinib in chronic myeloid leukemia. We screened for mutations 171 patients failing imatinib therapy. Sixty-six mutations in 23 amino acids were identified in 62 (36%) patients not responding to imatinib. Phosphate-binding loop (P-loop) mutations were the most frequent (n=24; 36%). By multivariate analysis, factors associated with development of mutations were older age (P=0.026) prior interferon therapy (P=0.026), and accelerated phase or blast phase at time of imatinib failure (P=0.001). After a median follow-up of 38 months (range, 4-68 months) from the start of imatinib therapy, seven patients with non-P-loop and two with P-loop mutation died. By multivariate analysis, development of clonal evolution and higher percentage of peripheral blood basophils were associated with worse survival from the time of imatinib failure. Mutation status had no impact on survival. When survival was measured from the time therapy started, non-P-loop mutations together with duration of response and transformation at the time of failure to imatinib were associated with shorter survival. In conclusion, P-loop mutations were not associated with poor outcome, suggesting that the prognosis of patients who fail imatinib is multifactorial.

Response to therapy is independently associated with survival prolongation in chronic myelogenous leukemia in the blastic phase.

BACKGROUND: Achievement of minimal tumor burden, such as complete response, has been accepted as a surrogate marker for improved survival in many solid and hematologic carcinomas. Several new agents have been approved recently for orphan disease indications or unmet medical needs, based on response analyses. This has not been the case for chronic myelogenous leukemia in the blastic phase (CML-BP), despite its poor prognosis, because response has not been proven to be a valuable endpoint for survival prolongation. The purpose of this study was to analyze the effect of response in CML-BP on survival prolongation. STUDY GROUP AND METHODS In total, 328 patients with CML-BP referred from 1989 to 1999 were studied; 311 patients received therapy for CML-BP, and 275 were evaluable for response. Blastic phase CML was defined by the presence of 30% or more blasts in the blood or bone marrow, or extramedullary disease. Treatment responses were reviewed and categorized as proposed in previous large studies. Four categoric response groups were defined further based on significant differences in outcome: cytogenetic response, hematologic response, bone marrow improvement, and failure. The association of treatment response with survival was evaluated by multivariate and landmark analyses. RESULTS: The association of response with survival was analyzed among the 275 patients who had evaluable responses, and follow-up information was documented. Univariate analysis of pretreatment characteristics found performance status, hemoglobin levels, platelet counts, peripheral blasts, additional chromosomal abnormalities, and blastic phase morphology as showing significant associations with survival (P < 0.1). A multivariate analysis found platelet counts and blastic morphology as independent significant factors associated with survival (P < 0.05). A landmark analysis conducted at 8 weeks from start of therapy showed the beneficial effect of achieving response on survival prolongation (P < 0.001). A repeat multivariate at the 8-week landmark time in the 240 patients alive at that time, which included pretreatment characteristics and treatment response, confirmed the independent significant association of morphology (P = 0.003), platelet counts (P = 0.04), and response (P < 0.001) with survival. CONCLUSIONS: Response to therapy is a significant independent factor associated with survival prolongation and maybe an acceptable therapeutic endpoint for approving new treatments in CML-BP.

Expression of apoptosis proteins in chronic myelogenous leukemia: associations and significance.

BACKGROUND: The mechanisms favoring the growth advantage of Philadelphia chromosome positive cells over normal cells in chronic myelogenous leukemia (CML) are not fully elucidated but could be due partly to altered apoptosis and longer survival of CML clones. Also, little is known about the biologic characteristics of disease progression in CML. Bcl-2 expression has been demonstrated to exert an antiapoptotic effect resulting in increased cell survival. Other proteins such as Bax and Bad are proapoptotic proteins. Fas, a cell surface protein, can be triggered by an appropriate death-promoting ligand (FasL) to activate downstream caspases pivotal in initiation of programmed cell death. Although the mechanisms underlying cellular proliferative and apoptotic pathways are complex, with involvement of multiple interlocking proteins, the relative expression of pro- and antiapoptotic proteins may have an influence on disease progression. This study aimed to determine whether the changes in the cellular expression of Bcl-2, Bax, and Fas correlate with caspase-3 activity and disease progression in CML, or with response to interferon (IFN)-alpha therapy and prognosis in early chronic phase CML. METHODS: Bcl-2, Bax, and Fas expression were measured on whole cell lysates from bone marrow mononuclear cell fractions by Western blot analysis and quantitative radioimmunoassay. Caspase-3 activity was determined using the DEVD system. Specimens from 203 patients with CML were examined. These included 130 patients in early chronic phase disease (ECP; diagnosis to therapy, < or =12 months), 33 patients in late chronic phase (diagnosis to therapy, > 12 months), 27 patients in accelerated phase, and 13 patients in blastic phase. Correlations between apoptosis proteins and CML phases, risk groups in ECP, and response to IFN-alpha therapy and survival in ECP were investigated by standard statistical methods, and positive findings were assessed by multivariate analysis. RESULTS: Levels of Bcl-2, Fas, Bax, and caspase-3 activity did not correlate with disease progression. Among patients in ECP, higher Fas levels correlated with poorer risk groups (P = 0.05) and higher caspase-3 activity correlated with better risk groups (P = 0.048). With IFN-alpha therapy, major cytogenetic responses were noted in 30% of patients with high Fas and 53% with low Fas (P = 0.016) and failure to achieve a complete hematologic response (CHR) in 25% versus 2% (P = 0.0001). Survival was shorter with high Fas levels (5-year rates, 71% vs. 52%; P = 0.002), and the independent poor prognostic significance of high Fas levels was confirmed by multivariate analysis (P = 0.014). Response to IFN-alpha therapy and survival were not significantly different by different levels of Bcl-2, Bax, or caspase-3 activity. CONCLUSIONS: High Fas levels were associated with intrinsically worse disease at diagnosis, whereas high caspase-3 activity was associated with good risk disease. In ECP CML, high Fas levels were associated with significantly worse response to IFN-alpha therapy and with significantly worse survival. The influence of these cellular proteins and caspase-3 activity on apoptosis in CML is complex and merits further investigation.

Results of therapy with interferon alpha and cyclic combination chemotherapy in patients with philadelphia chromosome positive chronic myelogenous leukemia in early chronic phase.

The objective of the study was to investigate the toxicity and efficacy of cyclic combination therapy offered to patients with Ph-positive CML having a sub-optimal response to IFN-alpha. Patients in early chronic phase CML were treated with IFN-alpha at 5MU/m(2) daily. Patients who did not achieve cytogenetic response after 6 months of IFN-alpha therapy, or Ph-suppression to less than 35% Ph-positive cells (partial cytogenetic response) after 12 months of therapy were offered cyclic intensive chemotherapy every 6 months, with IFN-alpha maintenance between cycles. The initial 3 cycles included daunorubicin, vincristine, cytosine arabinoside (ara-C) and prednisone (DOAP). Later cycles were given with cyclophosphamide replacing daunorubicin (COAP). Of 74 patients treated, 61 (82%) achieved complete hematologic response (CHR): 51 (69%) had a cytogenetic response, which was major (Ph < 35%) in 31 (42%), and complete in 23 (31%). Fifty-five patients (74%) achieved CHR by 6 months of therapy, 38 (69%; 51% of total) with a cytogenetic response - 13 (24%) had a major cytogenetic response. Seventeen patients received at least 1 course of DOAP therapy. Median survival of the overall cohort of patients was 120 months. With a median follow-up of 145 months (103+ to 155+ months), 40 patients (54%) have died. The median duration of cytogenetic response was 35 months (range 3 to 149+ months) and the estimated 10-year cytogenetic response rate was 37%. A durable complete cytogenetic response was observed in 16 patients (20%) with a median duration of 139+ months (range 12+ to 149+ months), 11 of them (15%) are now off IFN-alpha therapy for a median of 57+ months (range 12+ to 128+ months). The projected 10-year survival was 50% for the study group versus 35% for 208 patients who received other IFN-alpha based regimens at the MD Anderson Cancer Center (p<.01). In conclusion, the addition of intensive chemotherapy may improve survival in patients with CML who have not obtained an adequate cytogenetic response on an IFN-alpha-based regimen.

Homoharringtonine and low-dose cytarabine in the management of late chronic-phase chronic myelogenous leukemia.

PURPOSE: : To evaluate the efficacy and toxicity profiles of a combination regimen of homoharringtonine (HHT) and low-dose cytarabine (ara-C) in patients with Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) who had experienced treatment failure with interferon alfa (IFNalpha) therapy. PATIENTS AND METHODS: One hundred five patients were treated: 100 in chronic phase (15 with cytogenetic clonal evolution) and five in accelerated phase. Their median age was 52 years; all had been treated unsuccessfully with IFNalpha; 94% were in late chronic phase; 43% had been exposed to ara-C and 11% had been exposed to HHT. Patients received HHT 2.5 mg/m(2) by continuous infusion daily for 5 days and ara-C 15mg/m(2) daily in two subcutaneous injections for 5 days every 4 weeks. The outcome of the 100 patients in chronic phase was compared with a previous study group of 73 patients treated with HHT alone. RESULTS: Overall, the complete hematologic response (CHR) rate in chronic phase was 72%; the cytogenetic response rate was 32% (major response, 15%; complete response, 5%). Toxicities were acceptable, mostly related to moderate diarrhea (3%), headaches (3%), cardiovascular events (3%),and myelosuppression-associated complications (3% to 14%). With a median follow-up period of 25 months, the estimated 4-year survival rate was 55%. Response rates were identical with HHT plus ara-C versus HHT alone, but the survival was significantly longer with the combination after accounting for differences in the study groups and by multivariate analysis. CONCLUSION: The combination regimen of HHT and ara-C is effective and safe in patients with CML who have experienced treatment failure with IFNalpha and needs to be investigated together with IFNalpha as part of front-line CML therapy. The addition of ara-C did not improve the response rates but may have improved survival, perhaps through suppression of clones related to disease transformation.

Serum beta-2 microglobulin levels are a significant prognostic factor in Philadelphia chromosome-positive chronic myelogenous leukemia.

Our objective was to investigate the prognostic significance of serum beta-2 microglobulin (B2M) levels among patients with chronic myelogenous leukemia (CML). All patients with Philadelphia chromosome-positive early chronic phase CML (i.e., within 1 year of diagnosis) treated with IFN alpha-based therapy at the M. D. Anderson Cancer Center between 1980 and 1997, in whom pretreatment B2M levels were available, were investigated. Two hundred one patients were evaluable. Their median B2M was 2.2 mg/dl (range, 1.1-20 mg/dl). Serum B2M levels were associated with other variables of prognostic significance, including age, spleen size, WBC count, percentage of peripheral and marrow blasts, and percentage of marrow basophils. Patients with B2M levels >2.9 mg/dl (ie., the upper quartile of the distribution) had a significantly lower rate of major cytogenetic response compared to those in the lower three quartiles (20 versus 52%; P < 0.01). They also had a shorter survival, with a 5-year survival rate of 48%, compared with 75% for those in the lower quartiles (P = 0.01). High B2M levels (>2.9 mg/dl) could identify a group of patients with an adverse outcome within patients in stage I disease (P = 0.02). Results for patients in stages 2-4 were inconclusive because of the small number of patients in these groups. We conclude that serum B2M levels are an important, and probably independent, prognostic factor for patients with CML in early chronic phase treated with IFN-based therapy.

A phase I-II trial of escalating doses of mitoxantrone with fixed doses of cytarabine plus fludarabine as salvage therapy for patients with acute leukemia and the blastic phase of chronic myelogenous leukemia.

BACKGROUND: Cytarabine is an essential drug for inducing remission of acute myelogenous leukemia, and it is also one the most effective drugs used as salvage therapy for patients with all types of relapsed acute leukemia. Nevertheless, there is considerable room for improvement in the treatment of patients with relapsed leukemia in terms of both the reinduction rate and the duration of response. Fludarabine has been shown to augment responses to cytarabine, possibly by increasing the intracellular concentrations of the active metabolite cytarabine triphosphate. Higher-than-standard doses of mitoxantrone have been shown to augment responses to cytarabine, possibly by increasing the DNA strand breaks induced by topoisomerase II; these strand breaks cannot be effectively repaired in the presence of cytarabine triphosphate. This preliminary study was designed to determine whether moderately high doses of mitoxantrone could be added to the combination of fludarabine and cytarabine in an attempt to improve the combination's antileukemic efficacy. METHODS: Fifty-five adults with relapsed or refractory acute leukemia or the blastic phase of chronic myelogenous leukemia (CML) received salvage therapy with the FLAM regimen, which consisted of fludarabine, cytarabine, and increasing doses of mitoxantrone. RESULTS: Even with doses of mitoxantrone escalated to as much as 60 mg/m(2) over 4 days, dose-limiting toxicity was not observed. Overall, the complete response rate was 27.3% (15 of 55 patients, including 4 of 17 with acute myelogenous leukemia [AML], 4 of 12 with acute lymphocytic leukemia [ALL], and 7 of 26 with the blastic phase of CML). The median time to complete response was 42 days. Toxicity other than myelosuppression was manifested primarily as hyperbilirubinemia, which was reversible in all cases. Poor performance status and undifferentiated blastic phase of CML were poor prognostic factors for response to FLAM. CONCLUSIONS: The FLAM regimen is an active salvage regimen and should be formally evaluated in Phase II studies of patients with AML, ALL, and the myeloid and lymphoid blastic phases of CML.

Unexpected high incidence of severe toxicities associated with alpha interferon, low-dose cytosine arabinoside and all-trans retinoic acid in patients with chronic myelogenous leukemia.

Preclinical data have shown that all-trans retinoic acid (ATRA) with interferon-alpha (IFN-alpha) can exert significant suppressive effects on Philadelphia-chromosome (Ph)-positive cells. The aim of this study combining IFN-alpha, low-dose cytosine arabinoside (ara-C) and ATRA was to increase the proportion of patients achieving a major cytogenetic response, in comparison with a group of 140 patients previously treated with IFN-alpha plus low-dose ara-C. Forty three patients with Ph-positive CML in early chronic phase were treated with IFN-alpha 5 MU/m2 s.c. daily, low-dose ara-C 10 mg s.c. daily and ATRA 45 mg/m2 orally daily, for 7 consecutive days every other week. Overall, 76% of patients achieved a complete hematologic response (CHR). A cytogenetic response was in observed 59% (major in 38% and complete in 17%). Compared with patients treated with IFN-alpha and low-dose ara-C, those receiving additional ATRA had a lower CHR rate (p. 014), but other response rates were similar. Severe toxicities were common with the triple regimen (64%), mostly related to ATRA therapy. Two patients experienced pseudotumor cerebri; two patients had leukocytosis during the week on ATRA treatment, decreasing during the week off (one suffered a severe asthma-like reaction followed by pulmonary edema, resembling ATRA syndrome). Six patients had other unusual side-effects: aseptic necrosis of the hip (1 patient), ataxic syndrome (1 patient), paranoid syndrome (2 patients), syncopal episodes (1 patient), pure red cell aplasia (1 patient). In conclusion the results of IFN-alpha and low-dose ara-C combined with ATRA in patients with early CML-chronic phase were disappointing, due to excessive toxicity. Whether different ATRA dose schedules may result in fewer side-effects and improve hematologic and cytogenetic response remains to be determined.

Chronic myelogenous leukemia in nonlymphoid blastic phase: analysis of the results of first salvage therapy with three different treatment approaches for 162 patients.

BACKGROUND: The prognoses of patients with chronic myelogenous leukemia in blastic phase (CML-BP) are extremely poor. Treatment of patients with nonlymphoid CML-BP is associated with very low response rates, a median survival of 2-3 months, and significant toxicities. The aim of this study was to evaluate the results of therapy in CML-BP with different treatments in relation to response rate, survival, and toxicity. METHODS: A total of 162 adults patients with a diagnosis of nonlymphoid CML-BP referred from 1986 to 1997 were included in this analysis. Only first salvage therapy was considered for the purpose of this analysis. The blastic phase of CML was defined by the presence of 30% or more blasts in the blood or bone marrow, or extramedullary disease. Ninety patients were treated with intensive chemotherapy, 31 with decitabine, and 41 with other single agents. RESULTS: Thirty-six patients (22%) had an objective response. Response rates were similar among patients treated with intensive chemotherapy (28%) or with decitabine (26%). In aggregate, other single agents showed objective response rates of 7%. The median duration of remission for all patients was 29 weeks and the median overall survival 22 weeks. Patients treated with decitabine showed a trend toward better survival, despite a higher percentage of older patients (P < 0.004). The median survival times were 29 weeks with decitabine, 21 weeks with intensive chemotherapy, and 22 weeks with other agents. When only older patients were considered, survival was significantly better with decitabine versus other treatments (P < 0.01). A multivariate analysis of prognostic factors for survival confirmed the independent, significant favorable effect of decitabine therapy (P = 0.047). In all groups complications of myelosuppression were the most significant side effects. Severe nonhematologic toxicities were not observed in patients treated with decitabine; they occurred in 20% and 17% of patients treated with intensive chemotherapy or other single agents, respectively. CONCLUSIONS: Compared with intensive chemotherapy, decitabine showed favorable results, with similar objective response rates, a better nonhematologic toxicity profile, and a trend for better survival, particularly among older patients. Studies will now attempt to combine decitabine with other promising approaches, such as homoharringtonine, low dose cytarabine, and interferon-alpha, in all CML phases.

Analysis of Philadelphia chromosome-negative BCR-ABL-positive chronic myelogenous leukemia by hypermetaphase fluorescence in situ hybridization.

BACKGROUND: In 5%-10% of patients with of chronic myelogenous leukemia (CML), the Philadelphia chromosome (Ph) is not identified, despite the presence of the associated BCR-ABL molecular abnormality (Ph-negative, BCR-ABL-positive CML) because of sub-microscopic rearrangements. PATIENTS AND METHODS: Six patients with Ph-negative, BCR-ABL-positive CML were investigated. The Ph chromosome detection via fluorescence in situ hybridization after 24-hour mitotic arrest of bone marrow cultures resulting in several hundreds of metaphases (hypermetaphase FISH or HMF) was useful in explaining the nature of the six cases. RESULTS: Four patients had a low frequency of Ph-positive cells by HMF (5.7%, 4.8%, 3.9%, 0.2%), i.e., a typical Ph translocation. However, two cases involved a 9q34 inserted into chromosome 22q11 (74.2% and 92%), without a deletion from chromosome 22 and reciprocal translocation onto 9, i.e., not a typical Ph translocation. The pattern of UBCR gene rearrangement was characterized by the same genomic recombination of 5-BCR and c-ABL, both in the four cases of typical translocation (9;22) and in the two cases of insertion of 9q34 into chromosome 22q11. CONCLUSIONS: The HMF identified two different bases for Ph-negative, BCR-ABL-positive cells in CML-presence of low frequency of cells with typical Ph translocations or presence of cells with ABL insertions into the BCR gene on chromosome 22.

Phase I study of arabinosyl-5-azacytidine (fazarabine) in adult acute leukemia and chronic myelogenous leukemia in blastic phase.

Fazarabine has demonstrated a broad spectrum of antitumor activity in experimental models including P388 and L1210 cell lines. Previous phase I clinical trials using a 3-day continuous infusion schedule of Fazarabine have shown myelosuppression to be the dose limiting toxicity in solid tumors. Based on this clinical and preclinical experience we designed a phase I study to determine the toxicity, maximum tolerated dose (MTD), and antileukemic efficacy of Fazarabine using a 3-day continuous infusion schedule in patients with refractory or relapsed acute leukemia or chronic myelogenous (CML) in blastic phase. Adults with a diagnosis of acute leukemia or blastic phase CML who were refractory or had relapsed on salvage chemotherapy were entered on study. Fazarabine was administered as a continuous infusion over 3 days every 3 to 4 weeks. The initial dose was 2 mg/m2/hour x 72 hours. Results showed that the MTD was 425 mg/m2/hour infused over 72 hours every 3 to 4 weeks. At this dose level neurotoxicity and fluid overload were the dose limiting toxicities. Among 71 patients treated, we observed one complete remission, one partial remission and one hematologic improvement. No obvious dose response relationship could be determined. In conclusion, Fazarabine has not shown a beneficial effect in the therapy of acute leukemia. Since 71 patients and 20 dose levels were required to determine the MTD of Fazarabine, a reassessment of our phase I study designs should be considered to provide patients with better potential toxic: therapeutic benefits in such trials.

Treatment of Philadelphia chromosome-positive early chronic phase chronic myelogenous leukemia with daily doses of interferon alpha and low-dose cytarabine.

PURPOSE: To evaluate the efficacy of the combination of interferon alpha (IFN-alpha) and daily low-dose cytarabine (ara-C) in the treatment of patients with early chronic-phase chronic myelogenous leukemia (CML) (within 1 year of diagnosis). Improving the degree of hematologic and cytogenetic response in patients with Philadelphia chromosome (Ph)-positive CML may improve prognosis. Both IFN-alpha and ara-C induce cytogenetic responses as single-agent therapy in CML. PATIENTS AND METHODS: One hundred forty patients with Ph-positive early chronic-phase CML received subcutaneous injections of IFN-alpha 5 megaunits/m2 daily and ara-C 10 mg daily. Their median age was 46 years; 53% had good-risk disease, 33% had intermediate-risk disease, and 14% had poor-risk disease. Their results were compared with those of patients receiving IFN-alpha with or without intermittent ara-C (7 days/mo). RESULTS: A complete hematologic response (CHR) was achieved in 92% of patients. A cytogenetic response was seen in 74%: it was major in 50% (Ph-positive < 35%) and complete in 31% (Ph-positive 0%). With a median follow-up of 42 months, the 4-year estimated survival rote was 70% (95% confidence interval, 61% to 79%). Significant side effects included fatigue (43%; grade 3/4, 11%), weight loss (19%; grade 3/4, 11%), muscle and bone aches (20%; grade 3/4, 7%), oral ulcers (4%), diarrhea (6%), and neurologic changes (27%, grade 3/4, 6%). The median dose of IFN-alpha was 3.7 megaunits/m2 daily, mainly because of reductions for myelosuppression (70% of cases); the median ara-C dose was 7.5 mg daily. Prognostic risk groups were predictive for response to the IFN-alpha plus ara-C combination. The incidence of CHR was higher with IFN-alpha plus daily ara-C compared with IFN-alpha plus intermittent ara-C and IFN-alpha alone (no ara-C) (92% v 84% v 80%, P = .01), as were the incidences of cytogenetic response (74% v 73% v 58%; P = .003) and major cytogenetic response (50% v 38% v 38%; P = .06). The median time to achievement of major cytogenetic response was significantly shorter than that for previous IFN-alpha regimens (7 v 10 v 12 months; P < .01). However, with the present follow-up, the survival and time to blastic transformation were similar. CONCLUSION: The combination of IFN-alpha plus daily low-dose ara-C seems to be promising for the treatment of CML. High rates of CHR and cytogenetic response were observed with acceptable toxicity and a lower daily dose of IFN-alpha compared with our previous studies.

Sequential homoharringtonine and interferon-alpha in the treatment of early chronic phase chronic myelogenous leukemia.

Homoharringtonine (HHT) is a novel plant alkaloid that produced a complete hematologic remission (CHR) in 72% of patients with late chronic phase chronic myelogenous leukemia (CML). Cytogenetic (CG) remissions were noted in 31%. In this study, six courses of HHT were administered to 90 patients with early chronic phase CML (< 1 year from diagnosis). Patients then received interferon-alpha (IFN-alpha) with a target dose of 5 MU/m2 daily. Results were compared with those in a prior group of patients treated with IFN-alpha-based therapy between 1982 and 1990. Ninety-two percent of patients achieved CHR with HHT; CG responses were observed in 60% and were major in 27%. Both CHR and CG response rates were significantly higher than those seen in historical control patients after 6 months of IFN-alpha therapy. After receiving HHT, patients required lower doses of IFN-alpha to maintain a CHR. The median dose delivered was 2.4 MU/m2. This reduction in IFN-alpha dose was associated with a lower incidence of myalgia and gastrointestinal (GI) disturbances than that seen in patients treated at the 5 MU/m2 dose. Overall, CG responses were seen in 66% of the patients who received HHT and IFN-alpha compared with 61% of the historical control patients. HHT is a very effective treatment of early chronic phase CML, and ongoing trials are investigating the simultaneous administration of HHT and IFN-alpha, as well as that of HHT and low-dose cytosine arabinoside in patients failing IFN-alpha therapy.

Significance of FHIT expression in chronic myelogenous leukemia.

Loss or reduced expression of the fragile histidine triad (FHIT) gene, a tumor suppressor gene localized at chromosome 3p14.2, is common in several solid and hematological cancers and has been associated with tumor progression and worse prognosis. The role of the FHIT gene in the pathogenesis of chronic myelogenous leukemia (CML) or its progression from a chronic phase to the accelerated and blastic phases is not known. The aim of this study was to evaluate whether Fhit protein expression is altered in CML, and whether it plays any role in CML progression, disease responsiveness to therapy, or prognosis. A total of 195 patients with Philadelphia chromosome-positive CML were evaluated, including 129 patients in early chronic phase (time from diagnosis to study, 12 months or less), 30 patients in late chronic phase, and 36 patients in the accelerated and blastic phases. The levels of cellular Fhit protein expression were determined using Western blot analysis and solid-phase RIA and compared to the levels in 31 normal marrows. The median Fhit expression in normal marrows was assigned a value of 1, and the levels in CML samples were normalized to the median of the normal control. Fhit levels in CML samples were evaluated in relation to CML phase and patient characteristics and prognosis in the early chronic phase. The median Fhit value in CML samples was 0.89 (range, 0.34-2.62). Eight of the 195 (4%) CML samples showed Fhit levels <0.5 and lacked detectable Fhit protein by Western blot. There was no difference in the levels of Fhit expression by different CML phases. In early chronic phase, reduced Fhit expression tended to be associated with leukocytosis (P = 0.04) and lower platelet counts (P = 0.01), but not with poorer-risk groups. No differences in response to IFN-alpha therapy or in survival were observed by different Fhit levels. Lack of Fhit protein expression was detected in 4% of CML cases, and reduced expression occurred in a subpopulation of patients. However, reduced Fhit expression is not associated with progression, response to therapy, or prognosis in CML.

Determinants of prognosis in late chronic-phase chronic myelogenous leukemia.

PURPOSE: Since interferon alfa (IFN-A) became an established treatment in chronic myelogenous leukemia (CML), more patients are referred to tertiary centers in late chronic phase (ie, > 12 months after diagnosis). Trials conducted in this phase cannot be evaluated precisely unless the features that determine prognosis in late chronic-phase CML are identified. The purpose of this study is to define the prognostic determinants of late chronic-phase CML. PATIENTS AND METHODS: From 1980 to 1997,257 consecutive CML patients referred in late chronic phase were studied. Their clinical characteristics at the time of referral and their association with survival were investigated. A staging model was designed. RESULTS: The median survival from time of referral was 43 months. Pretreatment characteristics associated with worse outcome included older age, poor performance status, splenomegaly, low albumin level, high percentage of blasts or basophils in peripheral blood (PB) or bone marrow, longer duration of chronic phase, and poor-risk group as defined by the Synthesis model. Prior exposure to IFN-A was not associated with worse outcome. By multivariate analysis, characteristics associated with shorter survival were age of 60 years or older, time from diagnosis of 3 years or greater, performance status of 1 or greater, PB basophils of 7% or greater, spleen 10 cm or greater, PB blasts 3% or greater, and albumin level less than 4 g/dL. A model that included age, duration of chronic phase, performance status, and PB basophils was generated. Patients with no, one, two, or three or greater adverse factors had median survivals of 71, 49, 26, and 19 months, respectively. CONCLUSION: A staging model for late chronic-phase CML can stratify patients in four groups with significantly different outcomes. If confirmed in independent populations, such a model could be considered in the analysis of future trials of treatment strategies in late chronic-phase CML.

Suppression of cytogenetic clonal evolution with interferon alfa therapy in patients with Philadelphia chromosome-positive chronic myelogenous leukemia.

PURPOSE: To investigate whether cytogenetic clonal evolution can be suppressed with interferon alfa (IFN-alpha) therapy in patients with chronic myelogenous leukemia (CML). PATIENTS AND METHODS: Ninety patients with CML and cytogenetic clonal evolution who received IFN-alpha-based regimens were analyzed. Clonal evolution was defined as the presence of karyotypic abnormalities in addition to the Philadelphia (Ph) chromosome. Patients were evaluated for the suppression of cytogenetic clonal evolution after therapy, the cytogenetic response, and survival. RESULTS: The median age of the population was 39 years (range, 15 to 70 years), median time from diagnosis to clonal evolution 14 months (range, 0 to 145 months), and median percentage of abnormal metaphases 18% (range, 4% to 100%). Fifty six patients (62%) achieved some suppression of cytogenetic clonal evolution; in 41 patients (46%), the suppression was complete. The overall median survival was 51 months, with 43% alive at 5 years. Patients who achieved a complete suppression of cytogenetic clonal evolution had a median survival of 66 months, with 51% alive at 5 years. Characteristics associated with a better response include a lower percentage of abnormal metaphases, time to cytogenetic clonal evolution of 24 months or less, and absence of other features of accelerated disease. A prognostic classification for cytogenetic clonal evolution defined three groups with complete response (CR) rates of 85%, 34%, and 0% (P < .0001) and median survival times of 58, 31, and 30 months, respectively (P=.02). CONCLUSION: Patients with cytogenetic clonal evolution can respond to IFN-alpha therapy, and this response is associated with longer survival. A previously described prognostic model separates patients into subsets with different probabilities of response to IFN-alpha and survival.

Results of decitabine therapy in the accelerated and blastic phases of chronic myelogenous leukemia.

The aim of the study was to evaluate the activity of decitabine, a hypomethylating agent, in the treatment of patients with chronic myelogenous leukemia (CML) in transformation. Thirty-seven patients with CML in blastic (20 patients) or accelerated phases (17 patients) were treated. Their median age was 52 years; 36 had Philadelphia chromosome-positive disease. Decitabine was given at 100 mg/m2 over 6 h every 12 h x 10 doses (1000 mg/m2) to 13 patients, and at 75 mg/m2 over 6 h every 12 h x 10 doses (750 mg/m2) to 24 patients. In blastic phase, two patients (10%) achieved a complete hematologic response (one with Ph suppression), and three (15%) had a hematologic improvement (marrow CR, platelets <100 x 10[3]/microl), for an overall response rate of 25%. In accelerated phase, six patients (35%) returned to a second chronic phase (two with Ph suppression), one (6%) had a hematologic improvement, and two (12%) had a partial hematologic response, for an overall response rate of 53%. Prolonged myelosuppression was the most significant side-effect. The median time to recovery of granulocytes above 500/microl was 48 days, and to recovery of platelets above 30 x 10(3)/microl, 31 days. Febrile episodes occurred in 25 patients (68%) including documented infections in 17 patients (46%). Decitabine has promising activity in CML. The most significant side-effect is prolonged myelosuppression. Decitabine may show activity in other myeloid disorders such as acute myeloid leukemia and myelodysplastic syndrome, as well as in other hematologic malignancies, alone or with other drug combinations. Its value in the context of stem cell support should also be investigated.

Tallimustine, an effective antileukemic agent in a severe combined immunodeficient mouse model of adult myelogenous leukemia, induces remissions in a phase I study.

Despite progress in leukemia therapy, only 20-30% of patients with acute myelogenous leukemia (AML) are cured. 1-beta-D-arabinofuranosylcytosine- and topoisomerase II-reactive drugs are the primary therapeutic agents used. The aim of this study was to evaluate the potential activity of tallimustine in leukemia. In this study, we first investigated the efficacy and toxic effects of tallimustine, a distamycin-A derivative, in a human leukemia model in severe combined immunodeficient (SCID) mice. On the basis of its dramatic activity in this preclinical study, a Phase I study of tallimustine at a starting dose of 300 microgram/m2/day for 3 days every 3-4 weeks was conducted in patients with refractory or relapsed leukemia. In SCID mice grafted with a human myelomonocytic leukemia cell line, tallimustine resulted in complete remission of disease in most mice at tolerable dosages ranging from 0.86 to 3.0 mg/kg/day for 3 days and was combined effectively and safely with a 2-day schedule of high-dose ara-C. In the Phase I study, 26 patients with refractory or relapsed leukemia were treated. The maximum tolerated dose was 900 microgram/m2/day for 3 days every 3-4 weeks. This dose was 3 times higher than the maximum tolerated dose in solid tumors and was limited by severe mucositis. Magnesium and potassium wasting were also observed, but other side effects (fatigue and gastrointestinal) were minor. Two (8%) patients with AML achieved complete remission and two achieved hematological improvement with persistent thrombocytopenia. The results of this study indicate that tallimustine has promising activity in AML. Future studies may combine tallimustine with other agents known to be active against AML, and investigate its activity in other hematological malignancies. The recommended Phase II single-agent dose of tallimustine is 750-900 microgram/m2/day for 3 days, and combination studies may start at 50-66% of this dose schedule. The SCID mouse model of human leukemia may be promising in the preclinical evaluation and selection of potential antileukemic agents.