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Alterations in the FLT3 gene, including internal tandem duplications (ITDs) and D835 mutations occur frequently in acute myelogenous leukemia. We investigated the prevalence and clinico-biological correlations of FLT3 ITDs and D835 mutations in 90 patients with acute promyelocytic leukemia (APL) receiving the AIDA protocol. Twenty patients in which both presentation and relapse material was available were analyzed sequentially. Thirty-three patients (37%) harbored the ITD, and seven (7.7%) the D835 mutation in blasts obtained at diagnosis. Presence of ITDs was strongly associated with high WBC count (P = 0.0001), M3 variant (P = 0.0004), and the short (BCR3) PML/RARalpha isoform (P = 0.003). There was no difference in response to induction in the two ITD+ve and ITD-ve groups, while a trend towards inferior outcome was observed for ITD+ve cases when analyzing disease-free survival (DFS) and relapse risk (RR). These differences, however, did not reach statistical significance. Sequential studies showed variable patterns in diagnostic and relapse material, ie ITD (-ve/-ve, +ve/+ve, +ve/-ve, -ve/+ve) and D835 (-ve/-ve, +ve/-ve, -ve/+ve). Our results indicate that FLT3 alterations are associated in APL with more aggressive clinical features and suggest that these lesions may not play a major role in leukemia progression.

The objective of the study was to evaluate the incidence, characteristics, treatment and outcome of acute megakaryoblastic leukemia (AMeL) in patients enrolled in GIMEMA trials. Between 1982 and 1999, 3603 new consecutive cases of AML aged over 15 years were admitted to GIMEMA trials. Of them, 24 were AMeL. The incidence of AMeL among AML patients enrolled in GIMEMA trials was 0.6% (24/3603). Diagnosis was based on morphological criteria. Out of 11 cytogenetic studies performed two presented chromosome 3 abnormalities. Twelve patients (50%) reached a CR, five (21%) died in induction and seven (27%) were unresponsive. The median duration of CR was 35 weeks (range 10-441). Seven patients underwent transplantation procedures (1 BMT, 4 aBMT, 2 aPBSCT). Four patients died in CR due to chemotherapy-related complications. Comparing the CR rate between AMeL and the other cases of AML enrolled in GIMEMA trials, no differences were observed. These results were mirrored for different age groups. The median survival was 40 weeks. At present, after a follow-up of a minimum of 2 years, only two patients are alive in CR, all the others having died. A 5-year Kaplan-Meier curve shows a disease-free survival of 17% and an actuarial overall survival of 10%. AMeL is a rare form of AML. The CR duration and the overall survival in this group of patients are very poor, even if similar to those observed in other AML. Furthermore, a high number of deaths in CR were observed. On the basis of these data, a specific therapeutic approach, possibly with innovative treatments, should be evaluated.

Extramedullary (EM) involvement occurs infrequently in acute promyelocytic leukemia (APL) and usually involves skin and CNS. We describe seven patients (four observed at a single institution) who relapsed in various sites of the auditory apparatus, including the external canal and middle ear (temporal bone). Front-line treatment included ATRA and chemotherapy (six patients) or chemotherapy alone (one patient). Three patients had concomitant hematologic relapse, two had molecular relapse and two were in hematologic and molecular remission when ear localization was documented. Local symptoms that stimulated further diagnostic studies included ear bleeding/discharge in the first patient, but were mild in the others (hypoacusia, five patients; earache, two patients). Ear involvement by leukemia was documented by histological and/or molecular studies after local surgery in five cases, and by CT scan or NMR in the remaining patients. We suggest that the ear might represent a specific sanctuary for disease involvement in APL.

We studied the impact of cytogenetics and kind of induction/consolidation therapy on 848 adult acute myeloid leukemia (AML) patients (age 15-83). The patients received three types of induction/consolidation regimen: standard (daunorubicin and cytosine arabinoside (3/7); two cycles); intensive (idarubicin, cytosine arabinoside and etoposide (ICE), plus mitoxantrone and intermediate-dose Ara-C (NOVIA)); and low-dose (low-dose cytosine arabinoside). CR patients under 60 years of age, if an HLA-identical donor was available received allogeneic stem cell transplantation (allo-SCT); otherwise, as part of the program, they underwent autologous (auto)-SCT. CR rates significantly associated with 'favorable' (inv(16), t(8;21)), 'intermediate' ('no abnormality', abn(11q23), +8, del(7q)) and 'unfavorable' (del (5q), -7, abn(3)(q21q26), t(6;9), 'complex' (more than three unrelated cytogenetic abnormalities)) karyotypes (88% vs 65% vs 36%, respectively; P = 0.0001). These trends were confirmed in all age groups. On therapeutic grounds, intensive induction did not determine significant increases of CR rates in any of the considered groups, with respect to standard induction. Low-dose induction was associated with significantly lower CR rates. Considering disease-free survival (DFS), multivariate analysis of the factors examined (including karyotype grouping) showed that only age > 60 years significantly affected outcome. However, in cases where intensive induction was adopted, 'favorable' karyotype was significantly related to longer DFS (P = 0.04). This was mainly due to the favorable outcome of t(8;21) patients treated with intensive induction. Patients receiving allo-SCT had significantly longer DFS (P = 0.005); in particular, allo-SCT significantly improved DFS in the 'favorable' and 'intermediate' groups (P = 0.04 and P = 0.048, respectively). In conclusion our study could provide some guidelines for AML therapy: (1) patients in the 'favorable' karyotype group seem to have a longer DFS when treated with an intensive induction/consolidation regimen, adopted before auto-SCT instead of standard induction; this underlines the importance of reinforcement of chemotherapy, not necessarily based on repeated high-dose AraC cycles. Allo-SCT, independently of induction/consolidation therapy, should be considered an alternative treatment; (2) patients in the 'intermediate' karyotype group should receive allo-SCT; (3) patients in the 'unfavorable' karyotype group should be treated using investigational chemotherapy, considering that even allo-SCT cannot provide a significantly longer DFS, but only a trend to a better prognosis.

The 'gold standard' for the treatment of polycythemia vera (PV) is to date undefined. We performed a retrospective analysis to evaluate the outcome of a cohort of PV patients treated with pipobroman (PB) at a single institution during a period of 20 years (November 1971-October 1991). During this period, a total of 366 adult PV patients were diagnosed according to Polycythemia Vera Study Group (PVSG) criteria. Of these, only 199 (54%) were treated with PB: 92 were males and 107 females, median age was 63.0 years (range 25.2-87.3 years). Major clinical characteristics at onset were as follows: 34 (17%) patients had splenomegaly >3 cm below costal margin, 70 (35%) had platelets >600,000/mm3, 79 (40%) had white blood cells >12,000 mm3; 97 (49%) had hypertension, 83 (42%) had minor neurological symptoms (as vertigo, headache, paresthesias), 33 (17%) had pruritus and 27 (13%) had thrombotic features. All patients received PB at the dosage of 1 mg/kg/day until response was achieved (hematocrit value <50% in males and <45% in females). Thereafter treatment was given according to toxicity and maintenance of response. All patients were phlebotomized before starting treatment (mean number of phlebotomies performed: three, range 2-4) and 47 of them received PB when hematocrit value was already reduced at response levels: therefore, while all patients are evaluable for acute and long-term toxicity, only 152/199 (76.4%) patients are evaluable for response to PB. During a median time of 2 months, all these 152 patients achieved the response; as maintenance, 128/199 (64.3%) patients were managed with PB alone and 71/199 (35.7%) patients received phlebotomies occasionally. Sixty-one out of 199 (30.6%) patients developed disease-related complications (25 neurological symptoms, 21 thrombotic complications, 12 cardiovascular problems, three hepatic failures). Eleven (5.5%) patients developed acute myelogenous leukemia (AML) after a median time of treatment of 89 months (range 33-188 months), 11 (5.5%) patients developed myelofibrosis (median time from treatment 71 months, range 31-182 months) and in six (3%) patients cancer occurred (median time from treatment 85 months, range 13-118 months). The cumulative risk of leukemia in PV was 2% (95% CI: 0-4%) and 6% (95% CI: 1-11%) at 5 and 10 years respectively; the cumulative risk of myelofibrosis was 2% (95% CI: 1-5%) and 9% (95% CI: 3-15%) at 5 and 10 years, respectively. As of May 1996, 33 (16.6%) patients are lost to follow-up, 40 (20.1%) are dead and 126 (63.3%) are alive with a median overall survival of 191 months. In conclusion, this retrospective analysis confirms the efficacy and safety of PB in PV patients and its low leukemogenic role; prospective studies are needed to evaluate the real impact of PB in the treatment of PV.

The outcome of a cohort of 218 consecutive patients who failed to respond to a single course of standard daunorubicin plus ARAC (three + seven) induction regimen has been retrospectively evaluated to assess the characteristics of this group of AML patients and the effectiveness of second-line induction programs. Seventy-four of the 218 patients (33.9%) attained complete remission with salvage chemotherapies. The multivariate analysis of pretherapy characteristics of the patients showed that peroxidase positivity and age were the most important factors in determining whether or not the patient would have a favorable response to second-line induction regimen. In addition, comparison of marrow characteristics at diagnosis with those of marrow after the first-line therapy (marrow leukemic index, MLI) provided the greatest differences between second-line CR and resistant patients. Finally, peroxidase positivity and MLI predicted for remission duration and overall survival. Allogeneic BMT, however, appeared the most important factor for survival and event-free survival of remitting patients. These results are of importance when considering that better defined prognostic factors provide an objective rationale for selecting appropriate strategies for the treatment of patients who do not respond to a single course of induction regimen.

Thirty-one patients with either advanced AML (18) or blastic CML (13) were treated with an intensive timed sequential combination of VP-16 (100 mg/m2/day i.v., days 1-3 and 8-10), intermediate-dose Ara-C (500 mg/m2 i.v. over 1 h q 12 h, days 1-3 and 8-10) and carboplatin (150 mg/m2/day i.v. continuous infusion, days 1-3 and 8-10). CR rates were 9/18 (50%) for patients with AML and 9/13 (69%) for those with blastic CML, for an overall CR rate of 58%. Among patients with AML, CR rates for specific subgroups were: primary resistant disease 2/6; resistant relapse 1/5; second relapse 6/7. Ten patients were refractory to VAC and three (10%) died of complications during marrow hypoplasia. Median overall survival was 7 months, and median DFS of the 18 responders 4 months. The major toxicity was myelosuppression and infection. The VAC regimen has significant activity and acceptable toxicity in myelogenous leukemias. The very high response rate observed in blastic CML warrants further testing of carboplatin-based regimens in this poor-risk form of leukemia.

We treated a patient with chronic myeloid leukaemia in accelerated phase with autologous bone marrow transplantation. Before reinfusion, cells were purged in vitro with a 26-mer phosphorothioate antisense oligodeoxynucleotide specific for the B2A2 junction. Incubation with antisense oligodeoxynucleotides produced a 24 and 41% reduction of CFU-GM and CD34+ cells, respectively. However, an in vitro test previously performed as a screening for patient inclusion in this procedure, revealed a 38 and 75% reduction of colony formation after 24-h and 168-h incubation, respectively. The patient showed bone marrow engraftment 15 days after reinfusion and haematological reconstitution after 17 and 25 days for platelets and neutrophils, respectively. Using fluorescence in situ hybridization in interphase nuclei, we demonstrated the presence of a proportion of Ph-negative cells in repeated controls after the autograft. The patient is now in unmaintained complete haematological remission 9 months after the autograft.

5-Aza-2'-deoxycytidine (Decitabine) is an analog of deoxycytidine now entering clinical trials in acute myeloid leukemia (AML) owing to a defined antileukemic activity mediated at least in part by DNA hypomethylation, altered gene expression, and induction of cell differentiation. In the present study, we examined the relationship between the in vitro sensitivity to Decitabine of blast progenitors and the clinical outcome, in nine AML patients treated in vivo with Decitabine within a phase II trial carried out at two different institutions. Leukemic blast progenitors in acute myeloid leukemia (AML) undergo terminal divisions giving rise to colonies in methylcellulose. The self-renewal capacity of blast progenitors is conversely reflected by a secondary methylcellulose assay after exponential growth of clonogenic cells in suspension cultures. Three out of four patients, in which clonogenic cells in methylcellulose were strongly suppressed by Decitabine and clonogenic growth of blasts cultured in suspension was only slightly affected, failed on Decitabine treatment in vivo. Two subjects, whose blast progenitors in suspension culture were significantly inhibited by Decitabine, obtained a positive hematological response (complete or partial remission, CR or PR) and an additional patient showing a similar in vitro pattern died in induction with an hypoplastic marrow without morphological evidence of persistant leukemia. Interestingly two patients displaying an unfavourable in vitro pattern (i.e. a minor suppression of self-renewal mitoses as evinced from suspension cultures) achieved a hematological response (CR and PR) upon in vivo therapy with Decitabine. The in vitro response to Decitabine of clonogenic progenitors from both these patients shifted to a favourable pattern (i.e. major suppression of self-renewal versus terminal mitoses) following manipulation of culture conditions by the addition or removal of exogenous growth factors. In addition, in a further patient refractory to treatment with Decitabine in vivo, similar alterations of the culture conditions were unable to modify the unfavourable pattern of response to the drug in vitro. Our results indicate that the sensitivity of blast progenitors in suspension cultures strongly correlates with the remission outcome of the patients. From our data, it also appears that alterations of culture microenvironment are able to modify the response of AML blasts to Decitabine, unveiling the 'hidden' sensitivity of leukemic progenitors to the drug in cases characterized by a discrepancy between in vivo and in vitro results, i.e. apparent in vitro resistance and favourable clinical outcome.

5-Aza-2'-deoxycytidine (Decitabine) is a new cytosine analog with potent antileukemic activity and able to induce in vitro gene activation and cellular differentiation by a mechanism probably involving DNA hypomethylation. The aim of this pilot study was to evaluate the efficacy and the toxicity of Decitabine, used as single induction agent, in the treatment of poor prognosis acute myeloid leukemia (AML) patients, and to explore its mechanism of action. A total of 12 patients were treated with Decitabine at 90-120 mg/m2 as a four hour intravenous infusion, three times daily for three consecutive days every four to six weeks. A minimum of two courses were required for response evaluation and to consider a patient as therapeutic failure. A total of 10/12 patients were fully evaluable for response; three patients achieved a complete remission (CR) and one a partial remission (PR). Extra-hematological toxicity was generally mild. As for the mechanism of action, both a differentiation induction effect and a cytotoxic mechanism have been observed. In particular, CRs and PRs were probably obtained through the induction of leukemia cell differentiation as shown by the kinetic of remission and immunotyping studies. The preliminary results of this ongoing study suggest that Decitabine may have a prominent role in the treatment of those AML patients with poor general conditions and/or advanced age.

A total of 74 patients with poor risk AML (median age 36.7 years, range 4.5-60.6) received a single course of a regimen including mitoxantrone (6 mg/m2 intravenous bolus daily, days 1 to 6), etoposide (80 mg/m2 intravenous over 1 h, daily, days 1 to 6) and intermediate-dose Ara-C (1 g/m2 over 6 h, daily days 1 to 6). 28 patients had failed initial remission induction with daunorubicin and conventional doses of Ara-C, 16 patients had secondary AML and 30 patients had relapsed from initial remission (five within six months, 15 over six months and ten after autologous or allogeneic bone marrow transplantation). Overall 41/74 patients (55%) achieved complete remission, 26 (35%) had resistant disease and seven (10%) died of infection during marrow hypoplasia. A 4-day course of the same regimen was given as consolidation to patients in complete remission. Subsequent antileukemic therapy was individualized. Profound myelosuppression and pancytopenia were universal resulting in fever or documented infections in almost 100% of patient; major hemorrhagic complications occurred in 39% of patients. Extrahematologic toxicity was mild to moderate consisting mostly of nausea and vomiting, oral mucositis and transient liver and cardiac dysfunction. We conclude that the MEC combination chemotherapy program seems to be an effective antileukemic regimen for secondary and advanced AML, with acceptable toxicity.

Granulocyte-macrophage colony-stimulating factor, (GM-CSF) was given at 8 micrograms/kg daily by continuous i.v. infusion for 72 h to six patients with acute myeloid leukemia (AML) in expansion and one with chronic myeloid leukemia in blastic crisis to determine whether it was possible to augment the proliferative activity of the neoplastic population. The percentage of marrow blasts in S phase (labeling index, LI) was increased in five patients (1.3-, 1.5-, 1.9-, 2.3- and 3.2-fold change). The increase in LI was similar 24 and 48 h after beginning GM-CSF. The RNA Index also increased in patients who showed an increased LI, suggesting that GM-CSF had recruited quiescent neoplastic cells into the cell cycle. Forty eight hours after beginning GM-CSF, chemotherapy was started. The fate of S phase cells, labeled in vivo with bromodeoxyuridine (BrdU) immediately before cytostatic treatment, was monitored. BrdU positive cells were identified by fluorescent antibody for up to 28 days. A preferential killing of BrdU (S phase) cells was observed in 5/7 patients who obtained a complete remission, whereas this was not apparent in the two patients who achieved only a partial remission. Chemotherapy induced a rapid and profound aplasia; its duration, however, was not significantly different from that observed in historical controls. GM-CSF may have a potential role in the treatment of AML, as this study shows that it recruits leukemic cells into the cell cycle without adversely prolonging aplasia after cycle-specific therapy.

Serum interleukin-2 (IL-2), soluble IL-2 receptors (sIL-2R) and tumor necrosis factor-alfa (TNF-alpha) levels were determined in 66 previously untreated consecutive patients with acute myeloid leukemia (AML) and in 22 normal volunteers. The following mean (+/- SE) values were observed in patients and controls, respectively: 35 +/- 14.7 (range 0.5-500) and 0.7 +/- 0.02 (0.5-0.8 U/ml for IL-2 (p = 0.001); 1622 +/- 289 (110-10,600) and 422 +/- 30 (207-666) U/ml for sIL-2R (p = 0.0001); 1247 +/- 196 (218-4672) and 152 +/- 11 (75-308) pg/ml for TNF-alpha (p = 0.0001). With respect to the FAB classification system, we found a significantly different distribution of serum IL-2 mean values in distinct subcategories, i.e. 3.4 +/- 1.9 U/ml in M1-M2-M3 and 42.4 +/- 20.4 U/ml in M4-M5 subgroups, respectively (p = 0.01), whereas sIL-2R and TNF-alpha levels were 1144 +/- 322 U/ml and 1120 +/- 317 pg/ml in M1-M2-M3 patients and 1945 +/- 317 U/ml and 1270 +/- 259 pg/ml in the M4-M5 group. A significantly positive correlation between TNF-alpha and sIL-2R (r = 0.53; p = 0.002) was also detected in the M4-M5 group. Sixty-three out of 66 patients received an intensive chemotherapy program. Univariate analysis showed that age and sIL-2R greater than 2000 U/ml significantly affected both complete remission rate and overall survival, whereas by multivariate analysis, age was the only independent variable significantly influencing survival. These data confirm recent in vitro evidence suggesting the role of IL-2, sIL-2R, and TNF-alpha in the control of normal hematopoiesis and leukemogenesis. Since the availability of recombinant cytokines for clinical use in AML, it is crucial to understand their spectrum of interaction in order to select the appropriate combination for in vivo administration.

Forty-seven patients with primary refractory, relapsed, and previously untreated, poor risk AML were entered into a phase II study of intermediate dose ARA-C (IDAC) (1 g/m2 i.v. over 6 hr, daily for 6 days) with sequential mitoxantrone (MITOX) (6 mg/m2 i.v. bolus 3 hr after the end of each ARA-C infusion). Overall, complete remission was induced in 31 patients (66%), and 1 additional patient entered a partial remission. Seven patients (15%) died of infection during marrow hypoplasia. Response to IDAC + MITOX was influenced by sensitivity to previous therapy: patients with primary refractory and early relapse AML responded less well to the regimen (CR rate 28% and 33%, respectively), as compared to those with previously untreated (CR rate 64%) or late relapse disease (CR rate 85%). Sixteen patients continue in CR at 1-12+ months. Except for the expected severe myelosuppression, the regimen was well tolerated with minimal extramedullary toxicity. The data indicate that the sequential combination of IDAC and MITOX is an effective and tolerable regimen for AML. Consideration should be given to applying this program at earlier stages of AML therapy.