Phase Chronic Myelogenous Leukemia Research Articles

Granulocytic Sarcoma (GS) as First Manifestation of AML.

Granulocytic sarcoma (GS), or chloroma is an extramedullary tumor of immature myeloid cells which occurs throughout the body, often associated with acute myeloid leukemia (AML) or in the accelerated phase of chronic myelogenous leukemia, but rarely as the first manifestation of AML, preceding the onset in marrow and blood by months or years[1, 2] Herein, we report GS of lymph nodes presenting as first manifestation of AMLCase ReportA 53 years old male presented with recurrent episodes of epigastric abdominal pain without history of trauma or infections, Physical examination was normal. Laboratory examination showed WBC 5.2, ANC 4.4, Hemoglobin 13.6 gm/dl, PLT.306, 000 and Retic 1.8. Computerized Tomography (CT) of abdomen and pelvis showed extensive abdominal and pelvic lymphadenopathy, gastric wall thickening and prominence of the pancreatic head versus peripancreatic lymphadenopathy. Subsequently Esophagogastroduodenscopy and colonoscopy were both negative for malignancy. Peripheral smear showed normal RBC, and no myeloblasts. Laparoscopic retroperitoneal lymph node biopsy revealed granulocytic sarcoma, with immunohistochemistry positive for CD43, CD117, CD68 and MPOBone marrow biopsy and aspirate were performed, showing increased M: E ratio, increased blasts (29%), with flow cytometry reporting positivity for CD13, CD33, CD34, CD117, and HLA-DR supporting the diagnosis of AML. Chromosomal analysis including Fluorescence in situ hybridization studies (FISH) showed no evidence of chromosomal abnormalities. Patient continued to have epigastric pain radiating to the back without fever, night sweats or weight loss.He was treated with standard induction chemotherapy with Ara-c (7 days) and Idarubicin (3days), resulting in complete remission with resolution of the abdominal and pelvic lymphadenopathy.Patient is currently receiving consolidation therapy with high dose Ara-cConclusionGranulocytic sarcoma is a rare disease. The overall prognosis is poor. However, AML-type chemotherapy appears to improve survival.

Targeting the Kinase Activity of the BCR-ABL Fusion Protein in Patients with Chronic Myeloid Leukemia

Imatinib mesylate is a major advance in the therapy of patients with chronic myelogenous leukemia (CML). Imatinib mesylate binds to the inactive conformation of BCR-ABL tyrosine kinase suppressing the Philadelphia chromosome positive clone in CML. Clinical studies have yielded impressive results in all phases of CML. With higher rates of complete cytogenetic response with imatinib, molecular monitoring of disease is now advisable in assessing response and determining prognosis. Emergence of resistance to imatinib may be manifest at the hematologic, cytogenetic, or molecular levels in patients who remain in chronic phase, or may be evidenced by the development of more advanced CML phases. Resistance and eventual clinical failure of imatinib occurs in most patients with blastic phase disease. Resistance may occur at the level of Bcr-Abl, with reduction or loss of imatinib effectiveness as a kinase inhibitor, or, despite retention of its inhibitory ability, with changes in the ability to deliver an effective dose at the cellular level, and/or, the leukemia becoming less dependent on Bcr-Abl. The various mechanisms underlying these differing, non-mutually exclusive, mechanisms of resistance must be understood to develop corresponding therapeutic remedies. We review the current data on imatinib in CML, the criteria for diagnosis of imatinib resistance, and the mechanisms that underlie such resistance in CML.

The early referral for reduced-intensity stem cell transplantation in patients with Ph1 (+) chronic myelogenous leukemia in chronic phase in the imatinib era: results of the Latin American Cooperative Oncohematology Group (LACOHG) prospective, multicenter study

Using a reduced-intensity stem cell transplantation (RIST) schedule, 24 patients with Philadelphia (Ph1) (+) chronic myelogenous leukemia (CML) in first chronic phase (CP) were prospectively allografted in four Latin American countries: México, Brazil, Colombia and Venezuela, using HLA-identical siblings as donors. The median age of the patients was 41 years (range 10-71 years); there were eight females. Patients received a median of 4.4 x 10(6)/kg CD34 cells. The median time to achieve above 0.5 x 10(9)/l granulocytes was 12 days, range 0-41 days, and the median time to achieve above 20 x 10(9)/l platelets was also 12 days, range 0-45 days. In all, 22 patients are alive 81-830 (median 497) days after RIST. The 830-day probability of survival is 92%, and the median survival has not been reached, being beyond 830 days. A total of 11 patients (46%) developed acute graft-versus-host disease (GVHD), and seven of 23 (30%) developed chronic GVHD. Two patients died 43 and 210 days after RIST, one as a result of sepsis and the other of chronic GVHD. The 100-day mortality was 4.4%, and transplant-related mortality was 8%. RIST for patients with CML in CP appears to be an adequate therapeutic option.

Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) represents about 14% of all leukemias and occurs with a frequency of about 1 in 100,000. It is rare in children. Symptoms include fatigue, weight loss, sweating, and abdominal discomfort from an enlarged spleen. The white blood cell count can range from 100-600 ul. CML has three phases: the chronic phase, accelerated phase, and blast phase. Most patients are diagnosed during the chronic phase. Ionizing radiation has been implicated in some cases of CML, but in most individuals no cause is known. The Philadelphia chromosome, an acquired genetic mutation represented by a translocation of chromosome 22 and chromosome 9, drives the leukemic changes in CML. Imatinib mesylate, a tyrosine kinase inhibitor, was approved in 2002 for the treatment of all phases of CML. Because of its effectiveness, imatinib has become the treatment of choice for most patients with CML. Stem cell transplantation also is an option for eligible patients. It is the only curative treatment for CML. Two drugs under study for patients who cannot tolerate or who become resistant to imatinib are BMS-354825 and AMN107. Oncology nurses who are knowledgeable about new therapies for CML can be effective resources for their patients.

METABOLISM AND DISPOSITION OF IMATINIB MESYLATE IN HEALTHY VOLUNTEERS

Imatinib mesylate (GLEEVEC, GLIVEC, formerly STI571) has demonstrated unprecedented efficacy as first-line therapy for treatment for all phases of chronic myelogenous leukemia and metastatic and unresectable malignant gastrointestinal stromal tumors. Disposition and biotransformation of imatinib were studied in four male healthy volunteers after a single oral dose of 239 mg of (14)C-labeled imatinib mesylate. Biological fluids were analyzed for total radioactivity, imatinib, and its main metabolite CGP74588. Metabolite patterns were determined by radio-high-performance liquid chromatography with off-line microplate solid scintillation counting and characterized by liquid chromatography-mass spectrometry. Imatinib treatment was well tolerated without serious adverse events. Absorption was rapid (t(max) 1-2 h) and complete with imatinib as the major radioactive compound in plasma. Maximum plasma concentrations were 0.921 +/- 0.095 mug/ml (mean +/- S.D., n = 4) for imatinib and 0.115 +/- 0.026 mug/ml for the pharmacologically active N-desmethyl metabolite (CGP74588). Mean plasma terminal elimination half-lives were 13.5 +/- 0.9 h for imatinib, 20.6 +/- 1.7 h for CGP74588, and 57.3 +/- 12.5 h for (14)C radioactivity. Imatinib was predominantly cleared through oxidative metabolism. Approximately 65 and 9% of total systemic exposure [AUC(0-24 h) (area under the concentration time curve) of radioactivity] corresponded to imatinib and CGP74588, respectively. The remaining proportion corresponded mainly to oxidized derivatives of imatinib and CGP74588. Imatinib and its metabolites were excreted predominantly via the biliary-fecal route. Excretion of radioactivity was slow with a mean radiocarbon recovery of 80% within 7 days (67% in feces, 13% in urine). Approximately 28 and 13% of the dose in the excreta corresponded to imatinib and CGP74588, respectively.

Synergistic interactions between imatinib mesylate and the novel phosphoinositide-dependent kinase-1 inhibitor OSU-03012 in overcoming imatinib mesylate resistance

AbstractResistance to the Ableson protein tyrosine (Abl) kinase inhibitor imatinib mesylate has become a critical issue for patients in advanced phases of chronic myelogenous leukemia. Imatinib-resistant tumor cells develop, in part, as a result of point mutations within the Abl kinase domain. As protein kinase B (Akt) plays a pivotal role in Abl oncogene-mediated cell survival, we hypothesize that concurrent inhibition of Akt will sensitize resistant cells to the residual apoptotic activity of imatinib mesylate, thereby overcoming the resistance. Here, we examined the effect of OSU-03012, a celecoxib-derived phosphoinositide-dependent kinase-1 (PDK-1) inhibitor, on imatinib mesylate-induced apoptosis in 2 clinically relevant breakpoint cluster region (Bcr)-Abl mutant cell lines, Ba/F3p210E255K and Ba/F3p210T315I. The 50% inhibitory concentration (IC50) values of imatinib mesylate to inhibit the proliferation of Ba/F3p210E255K and Ba/F3p210T315I were 14 ± 4 and 30 ± 2 μM, respectively. There was no cross-resistance to OSU-03012 in these mutant cells with an IC50 of 5 μM irrespective of mutations. Nevertheless, in the presence of OSU-03012 the susceptibility of these mutant cells to imatinib-induced apoptosis was significantly enhanced. This synergistic action was, at least in part, mediated through the concerted effect on phospho-Akt. Together these data provide a novel therapeutic strategy to overcome imatinib mesylate resistance, especially with the Abl mutant T315I.

Molecular Responses in Patients with Chronic Myelogenous Leukemia in Chronic Phase Treated with Imatinib Mesylate

To determine the clinical significance of molecular response and relapse among patients with chronic myelogenous leukemia (CML) treated with imatinib. We analyzed the results of quantitative PCR in 280 patients with CML in chronic phase who achieved complete cytogenetic remission with imatinib (117 after IFN-alpha failure and 163 previously untreated). Median follow-up was 31 months (range, 3-52 months). Median BCR-ABL/ABL ratio before the start of therapy was 39.44 (range, 0.252-170.53). A major molecular response (BCR-ABL/ABL ratio <0.05%) was achieved in 174 (62%), and transcripts became undetectable (complete molecular response) in 95 (34%). By multivariate analysis, only treatment with high-dose imatinib (P = 0.02) was associated with achievement of a major molecular response. Nine of 166 (5%) patients who achieved a major molecular response lost their cytogenetic remission, compared with 25 of 68 (37%) among those who did not achieve this response (P < 0.0001). Patients achieving a major molecular response 12 months after the start of therapy had significantly better complete cytogenetic remission duration than others. A >1-log reduction in transcript levels after 3 months of therapy predicted for an improved probability of achieving a major molecular response at 24 months. Increasing levels of BCR-ABL transcripts predicted for a loss of cytogenetic remission only among patients who did not achieve a major molecular response. Achieving a major molecular response, particularly within the first year of therapy, is predictive of a durable cytogenetic remission and may be the future goal of therapy in CML.

Survival benefit with imatinib mesylate therapy in patients with accelerated‐phase chronic myelogenous leukemia—Comparison with historic experience

The effect of imatinib mesylate on survival in the accelerated phase of chronic myelogenous leukemia (CML) is unknown. The objectives of this study were to update the long-term experience with imatinib in patients who had accelerated-phase CML and to compare outcomes with historic experience. The outcomes of 176 patients who received treatment with imatinib were reviewed and compared with the outcomes of 213 historic control patients with accelerated-phase CML who received treatment with interferon-alpha or with other modalities. With imatinib, the complete hematologic response rate was 82% versus a rate < or = 50% for others, and the complete cytogenetic response rate was 43% versus rates of 0-6% for others. The estimated 4-year survival rates were 53% with imatinib, 42% with interferon-alpha, and 0-21% for others. A multivariate analysis of the total population of 389 patients indicated that imatinib therapy (vs. other therapies) was an independent, favorable prognostic factor for survival (P < 0.0001; hazard rate, 0.62). A subset analysis that included only patients who were treated with imatinib and interferon-alpha (276 patients) also identified imatinib as an independent favorable prognostic factor (P < 0.0001; hazard rate, 0.65). The 3-month cytogenetic response to imatinib was associated with significantly different survival outcomes (P < 0.0001). A multivariate analysis that included pretreatment characteristics and 3-month cytogenetic response among 150 patients who received imatinib and were alive at 3 months identified only 2 adverse independent prognostic factors: lack of a cytogenetic response at 3 months (P < 0.001) and anemia (hemoglobin < 10 g/dL; P = 0.003). Patients who had neither factor (41%) had an estimated 4-year survival rate of 88%; in the other patients, the 4-year survival rate was < or = 60%. This may have implications in relation to subsequent therapy, because, according to the outcomes of patients who underwent allogeneic transplantation in accelerated phase at the authors' institution and from literature reports, the estimates of 5-year survival were 25-30%. The current results suggest that imatinib improved survival compared with other therapies in patients with accelerated-phase CML.

C/EBPδ expression in a BCR-ABL-positive cell line induces growth arrest and myeloid differentiation

CCAAT/enhancer-binding proteins (C/EBPs) are a family of highly conserved transcription factors that have important roles in normal myelopoiesis as well as associated with myeloid disorders. The chronic myelogenous leukemia (CML) cell lines, KCL22 and K562, express exceptionally low levels of endogenous C/EBPs and provide a good model to test the effects of C/EBPs on myeloid differentiation. To explore the possibility that C/EBPdelta can promote differentiation in BCR-ABL-positive cells, we generated stable KCL22 and K562 clones that expressed an inducible C/EBPdelta gene. C/EBPdelta expression resulted in G0/G1 proliferative arrest and a moderate increase in apoptosis of the KCL22 and the K562 cells. Within 4 days of inducing expression of C/EBPdelta, myeloid differentiation of the CML blast cells occurred as shown by morphologic changes and induction of secondary granule-specific genes. We also showed that during granulocytic differentiation of KCL22 cells, the C/EBPdelta protein was detected in immunocomplexes with both Rb and E2F1. Furthermore, expression of C/EBPdelta was associated with downregulation of c-Myc and cyclin E and upregulation of the cyclin-dependent kinase inhibitor p27(Kip1) in both the KCL22 and K562 cell lines. These results show that expression of C/EBPdelta in BCR-ABL-positive leukemic cells in blast crisis is sufficient for neutrophil differentiation and point to the therapeutic potential of ectopic induction of C/EBPdelta in the acute phase of CML.

Response of Elevated Serum Soluble Interleukin-2 Receptor (sIL-2R) and Overexpression of Glucose-6-Phosphate Dehydrogenase (G6PD) in Patients with Chronic Myelogenous Leukemia Treated with Imatinib Mesylate.

Regulation of intracellular redox potential is important for regulation of cell growth. G6PD functions to catalyze the first step in the pentose phosphate pathway physiologically providing the NADPH required for reductive biosynthesis and detoxification of free-radicals and peroxides in mature red blood cells. We present two cases of patients (pts) with Chronic Myelogenous Leukemia-chronic phase (CML-cp) with significant overexpression of sIL-2R and G6PD. Serum elevated levels of sIL-2R and G6PD correlated to CML stage and response to therapy with imatinib; one male pt and one female pt with white blood cell counts of 80 and 21,000 X 109 per liter and a mean sIL-2R and G6PD levels of 26.975 X 103 pg/ml and 14.10 units/gHb respectively. Both pts had BCR/abl-RT-PCR positive gene rearrangements with b2a2 in peripheral blood and bone marrow. Chromosomal abnormalities of female pt was consistent with CML-cp (t 9; 22) ( q34;q11.2) philadelphia chromosome. Treatment of both pts with imatinib 400 mg orally daily resulted in reduction toward normal levels of sIL-2R and G6PD. Our female pt had to have therapy interrupted due to severe gastrointestinal and myelosuppression with cardiac irritation, edema, headaches and arthralgia. She was changed to 300 mg of imatinib with a proton-pump inhibitor, growth factor G-CSF, and a cox-2 inhibitor with excellent tolerance and response to therapy ( see table I).Response of sIL-2R and G6PD To Treatment With Imatinib MesylateMONTHSLAP-SCOREsIL-2R (pg/ml)CRP (mg/dL)G6PD (units/gHb)LDH (U/L)Zero426,97516.011.1386Three125,6292.754.1241Six1712,8680.753.6266Twelve1436,1113.753.9203Lap Score(NL 40-130); sIL-2R (NL 1,770-9,753); G6PD (3.5–5.0)CONCLUSIONS: Overexpression of sIL-2R and G6PD in CML-cp pts treated with tyrosine kinase inhibitor imatinib mesylate were significantly reduced to levels within normal limits after twelve months of therapy. Peripheral blood sera sIL-2R and erythrocyte G6PD levels in CML-cp pts may be useful clinical and prognostic indicators of leukemic cell burden.

A Phase I Trial of Autologous Dendritic Cell Therapy for Chronic Myelogenous Leukemia.

This phase 1 clinical trial evaluated the safety and effects of autologous dendritic cells (DC) injected to patients in late chronic or accelerated phase of chronic myelogenous leukemia (CML). Seven patients with a median age of 63 years (range 55–78) entered the trial. Median time from diagnosis to registration was 38 months (range 16–94). Two patients were in the accelerated phase of disease based on the presence of additional bone marrow chromosomal abnormalities, all other patients were in chronic phase. Prior therapies included hydroxyurea and alpha interferon with or without cytosine arabinoside. Four patients were on therapy with imatinib mesylate during the course of the trial, two were treated before imatinib became available and one was previously intolerant of imatinib. CD14+ monocytes were selected from a leukapheresis product by clinical grade immunoadsorption (Miltenyi Biotec). The monocytes were matured to CD83+ and bcr-abl+ DC after 10 days in culture with X-VIVO 15 medium with 1% human AB serum, GM-CSF, IL-4, as the base culture media followed by maturation mediated by TNF-alpha, IL-6 and prostaglandin E2. The first patient entered had a positive mycoplasma reaction by polymerase chain reaction at the time of his first DC injection, the cells were not given and he was withdrawn from the study. The other six patients were treated in two cohorts of three patients and received four injections each of 3x106 DC and 15x106 DC per injection, respectively. CML-DC injections were generally well tolerated and all non-hematologic toxicities were ≤ grade 2. All injections were given intra-nodally into a cervical lymph node except in the first patient where the DCs were injected subcutaneously. We observed no major clinical responses, but the white blood cell counts normalized or were maintained at normal level in four patients during therapy. Three patients experienced a transient reduction in the percentage of bcr-abl+ cells suggesting that the treatment may have affected the cells in a leukemia specific manner. We detected vascular endothelial growth factor (VEGF) in the plasma prior to therapy. In four of five patients, VEGF levels decreased by more than 75 percent during therapy. T cells isolated from patients' blood and incubated with autologous CML DC before, during and after therapy showed increased proliferation and secretion of interferon gamma during the course of therapy. DCs from three patients were transfected with a recombinant replication-defective adenovirus carrying the gene for IL-2 under a constitutively active promoter. IL-2 secreted by transfected dendritic cells enhanced in vitro T cell proliferation and interferon gamma release and these effects increased with increasing numbers of DC injections. This study demonstrates that CML-DC can be prepared from the blood of patients treated with imatinib mesylate, that they can be administered safely and that progress of therapy is accompanied by an increase in DC-specific T cell reactivity and a decrease in circulating VEGF.

Gleevec Therapy in Advanced Phases of the Cml - Polish Study Report.

Accelerated phase marks the onset of advanced rapidly progressive chronic myelogenous leukaemia (CML) and generally leads finally to a fatal blast crisis (BC) within 6 months.Gleevec (imatinib mesylate) as a potent tyrosine kinase inhibitor has demonstrated significant activity in chronic phase (CP) of CML.Because of the observed activity and favorable tolerability of Gleevec and because of the limited treatment options available to these patients we have introduced Gleevec in CML patients meeting rigorous criteria for acceleration and blast crisis phase of CML.PATIENTS: MALE - 31 and FEMALE - 20 were eligible for inclusion in this study if they were at least 18 years old and had a diagnosis of Ph+ CML (AP; BC) confirmed by cytology, histology, cytogenetic and molecular analyses.Characteristics CML patients (AP-accelerated phase; BC-blast crisis phase) is showed in table 1.Table 1- Demographics, Disease History and Characteristics of CML Patients.Duration time of CML-yr3.8 (1–4.5)3.7 (0.7–5.1)Prior therapy -n(%)100%100%combined Chemotherapy10 (33)18 (86)BMT2 (6.6)0Sokal's score>0.816 (53)15 (71)PLT (x 109/L)100.0–300.011 (37)8 (38)>300.015 (50)4 (19)Blasts in peripheral blood (%)median934range4–2031–80Blasts in bone marrow (%)range10–2532–78HGB (g%)median6.246.12range5.0–9.44.4–10.0Gleevec dosageAPBC300mg: n (%)1 (3.3)1 (4.8%)400 mg: n (%)4 (13.3)1 (4.8)600–800 mg: n (%)25 (83.4)19 (90.4)Duration of treatment (months)APBCmedian31.6440.0range1–980.5–911Patients received Gleevec 300–800 mg orally daily (table 2). Clinical evaluation of Gleevec therapy was determined by the rate of sustained haematological response (lasting >= 4 weeks)The results of Gleevec therapy are showed in table 2.Table 2 - Haematologic Response in Patients with AP & BC Phase after Gleevec TreatmentResponseAPBCCHR25 (83.3%)4 (19.0%)Cytogenetic responseMajor :5 (16.7%)1 (4.8%)CCR2 (6.7%)0PCR3 (10.0%)1 (4.8%)Minimal11 (36.7%)1.4.8%)No response9 (30%)18 (85.6%)BMT performed5 (16.7%)2 (9.6%)after Gleevec therapy (months)6–127–132The most often observed side effects were irst few months ( neutropenia, thrombocytopenia, weakness, bone and muscles pain, headache, nausea, vomiting, diarrhoea, legs' oedema, deaths (6.3% – 27.3%).Conclusions:1.Imatinib as a single agent is well tolerated and has substantial activity in the accelerated phase of CML.2.The overall response rate in these cases was 83%. Imatinib as a single agent is well tolerated and has substantial activity in the accelerated phase of CML.3.The overall response rate in these cases was 83%. Imatinib as a single agent is well tolerated and has substantial activity in the accelerated phase of CML.4.The overall response rate in these cases was 83%.5.5 pts. out of these 30 patients are still in the chronic phase after 10 to 32 months of follow-up.6.In 4 ( 19%) out of 21 patients with BC the improvement after Gleevec therapy was short and transient mainly due to advanced stage of disease.

Granulocyte—colony‐stimulating factor (Filgrastim) may overcome imatinib‐induced neutropenia in patients with chronic‐phase myelogenous leukemia

BACKGROUND Imatinib mesylate administration has become standard treatment for patients with chronic myelogenous leukemia (CML). Although the safety profile of imatinib is favorable, Grade ≥ 3 neutropenia (according to the National Cancer Institute Common Toxicity Criteria) occurs in 35–45% of patients with CML in chronic phase who receive standard-dose imatinib. Myelosuppression results in treatment interruptions, which may compromise responses to imatinib. The authors investigated the ability of granulocyte–colony-stimulating factor (filgrastim) to reverse imatinib-associated neutropenia, thereby allowing for more continuous imatinib administration. METHODS Thirteen patients with chronic-phase CML and Grade ≥ 3, imatinib-induced neutropenia were treated with filgrastim. Treatment with filgrastim was initiated after a median of 22 months from the start of imatinib. Eleven patients received filgrastim 5 μg/kg 1–3 times weekly, and 2 patients received filgrastim 5 μg/kg daily; doses were titrated to maintain an absolute neutrophil count (ANC) ≥ 109/L. RESULTS Seven of 11 patients (64%) who began treatment with an ANC < 1.5 × 109/L had responses (i.e., their ANC improved to ≥ 2 × 109/L within 21 days); the other 4 patients experienced slower recovery but were able to continue receiving imatinib uninterrupted. Before filgrastim administration was initiated, patients did not receive imatinib (due to neutropenia-related treatment interruptions) for an average of 21% of the total time since the start of imatinib. This figure decreased to 6% after the start of filgrastim treatment (P = 0.0008). Before filgrastim treatment was initiated, only one patient had achieved a major (partial) cytogenetic response. After the start of filgrastim treatment, five patients had major cytogenetic responses (including two complete responses). CONCLUSIONS The authors concluded that filgrastim may overcome imatinib-associated neutropenia and allow improved delivery of imatinib. Some patients may experience improvements in their responses to therapy as a result. Cancer 2004. © 2004 American Cancer Society.

Reduced intensity conditioning and allogeneic stem cell transplantation (RI AlloSCT) in children and adolescents with malignancies following unrelated cord blood and matched family donor AlloSCT results in ≥90% achieving ≥98% donor chimerism

8506 Background: Although RI AlloSCT induces complete donor chimerism in adults with hematological malignancies (Slavin et al, Blood 91:756–763, 1998), there is little data in children and adolescents. We determined the degree of engraftment following RI AlloSCT in 14 children with malignant diseases following matched-family donor (MFD) and umbilical cord blood transplants (UCBT). Methods: Donors included: 8 unrelated UCB, 1 related UCB, and 5 related peripheral blood stem cells (PBSC). RI conditioning consisted of: fludarabine and busulfan +/- rabbit anti-thymocyte globulin (r-ATG) or alemtuzumab (N=12); and fludarabine, melphalan +/- horse ATG (N=2). Graft-vs.-host disease (GVHD) prophylaxis consisted of tacrolimus and mycophenolate mofetil. Demographics were as follows: median age 14.5 (0.5–21) yrs; 6 pts. with Hodgkin's disease (3 in 2nd CR, 1 in PR, 2 pts with PD), 1 pt with non-Hodgkin's lymphoma in PR, 2 pts with neuroblastoma - 1 in CR and one with PD, 2 pts with Wilms' tumor and PD, 1 pt with chronic myelogenous leukemia in chronic phase, and 2 pts with acute myelogenous leukemia in 1st CR. The UCB median cell dose was 3.43 × 107 NC/kg (0.9–10.8). The PBSC dose was 5.7 × 108 NC/kg (4.3–9.9). Results: Maximal donor chimerism (MDC) following UCBT was 100% for 7 pts, 98% for 1 pt, and 55% for 1 pt (died of PD on day +79), and 100% for all 5 pts after PBSC transplant. Graft failure was not observed. There was one non-infectious grade 4 toxicity (hepatic) secondary to busulfan, which resolved. The probability of developing acute GVHD grade II-IV in UCB vs. PBSC transplants was 11.11% (CI, 0–31.64) vs. 60.0% (CI, 38.1–81.9). The overall probability of chronic GVHD was 32.5% (CI, 0–73.2). The probability of 1-yr OS is 67.7 % (CI, 48.69–99.45). 1-yr OS for good-risk patients vs. poor-risk patients was 100% vs. 33.3% (CI, 20.47–93.81). Conclusions: RI AlloSCT is feasible and tolerable in children and adolescents with malignancies. Evaluation of graft-vs.-malignancy effect is ongoing, but 4 patients with active disease responded. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Roche Pharmaceuticals

Reduced intensity conditioning and allogeneic stem cell transplantation (RI AlloSCT) in children and adolescents with malignancies following unrelated cord blood and matched family donor AlloSCT results in ≥90% achieving ≥98% donor chimerism

8506 Background: Although RI AlloSCT induces complete donor chimerism in adults with hematological malignancies (Slavin et al, Blood 91:756–763, 1998), there is little data in children and adolescents. We determined the degree of engraftment following RI AlloSCT in 14 children with malignant diseases following matched-family donor (MFD) and umbilical cord blood transplants (UCBT). Methods: Donors included: 8 unrelated UCB, 1 related UCB, and 5 related peripheral blood stem cells (PBSC). RI conditioning consisted of: fludarabine and busulfan +/- rabbit anti-thymocyte globulin (r-ATG) or alemtuzumab (N=12); and fludarabine, melphalan +/- horse ATG (N=2). Graft-vs.-host disease (GVHD) prophylaxis consisted of tacrolimus and mycophenolate mofetil. Demographics were as follows: median age 14.5 (0.5–21) yrs; 6 pts. with Hodgkin's disease (3 in 2nd CR, 1 in PR, 2 pts with PD), 1 pt with non-Hodgkin's lymphoma in PR, 2 pts with neuroblastoma - 1 in CR and one with PD, 2 pts with Wilms' tumor and PD, 1 pt with chronic myelogenous leukemia in chronic phase, and 2 pts with acute myelogenous leukemia in 1st CR. The UCB median cell dose was 3.43 × 107 NC/kg (0.9–10.8). The PBSC dose was 5.7 × 108 NC/kg (4.3–9.9). Results: Maximal donor chimerism (MDC) following UCBT was 100% for 7 pts, 98% for 1 pt, and 55% for 1 pt (died of PD on day +79), and 100% for all 5 pts after PBSC transplant. Graft failure was not observed. There was one non-infectious grade 4 toxicity (hepatic) secondary to busulfan, which resolved. The probability of developing acute GVHD grade II-IV in UCB vs. PBSC transplants was 11.11% (CI, 0–31.64) vs. 60.0% (CI, 38.1–81.9). The overall probability of chronic GVHD was 32.5% (CI, 0–73.2). The probability of 1-yr OS is 67.7 % (CI, 48.69–99.45). 1-yr OS for good-risk patients vs. poor-risk patients was 100% vs. 33.3% (CI, 20.47–93.81). Conclusions: RI AlloSCT is feasible and tolerable in children and adolescents with malignancies. Evaluation of graft-vs.-malignancy effect is ongoing, but 4 patients with active disease responded. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Roche Pharmaceuticals

Long-term results of imatinib mesylate therapy in philadelphia chromosome (Ph) positive chronic phase chronic myelogenous leukemia (CML) post interferon-a (IFN) failure M.D. Anderson experience in 261 patients

6622 Background: The initial results of imatinib in Ph-positive CML in chronic phase post IFN failure were positive with a median follow up times of 17 months. The major cytogenetic (CG) response rate (Ph 5% (p<0.05) or prior hematologic resistance to IFN (p=0.01). Achieving any CG response at 3 months was associated with a 4-year survival rate of 95% (versus 78% for others; p=0.0001); the 4-year FFP rates were 94% versus 64%, respectively (p<0.0001). Achieving a major CG response at 6 months was associated with a 4-year survival rate of 95% (versus 81% for others; p=0.001); the 4-yr FFP rates were 94% versus 68% (p<0.0001). Among 167 patients achieving CG CR, 152 pts had quantitative PCR (QPCR) studies: 82 pts (49%; 31% total) had a major molecular response (QPCR= BCR-ABL/ABL <0.05%) and 38 pts (15%) had a complete molecular response (BCR-ABL undetectable). The 3-yr cumulative major molecular response rate was 55%, and complete molecular response rate 22%. Compared with a historical group of 131 similar patients in CML chronic phase post IFN failure treated with non-imatinib therapies, imatinib was associated with better 4-year survival rates (88%, versus 35% p<0.0001); this survival advantage for imatinib was confirmed by multivariate analysis (p<0.0001). Conclusions: The results with imatinib in CML chronic phase post IFN failure are improving and durable. Major and complete responses are now noted in a substantial proportion of patients with longer follow-up time. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis; Supergen

Long-term results of imatinib mesylate therapy in philadelphia chromosome (Ph) positive chronic phase chronic myelogenous leukemia (CML) post interferon-a (IFN) failure M.D. Anderson experience in 261 patients

6622 Background: The initial results of imatinib in Ph-positive CML in chronic phase post IFN failure were positive with a median follow up times of 17 months. The major cytogenetic (CG) response rate (Ph 5% (p<0.05) or prior hematologic resistance to IFN (p=0.01). Achieving any CG response at 3 months was associated with a 4-year survival rate of 95% (versus 78% for others; p=0.0001); the 4-year FFP rates were 94% versus 64%, respectively (p<0.0001). Achieving a major CG response at 6 months was associated with a 4-year survival rate of 95% (versus 81% for others; p=0.001); the 4-yr FFP rates were 94% versus 68% (p<0.0001). Among 167 patients achieving CG CR, 152 pts had quantitative PCR (QPCR) studies: 82 pts (49%; 31% total) had a major molecular response (QPCR= BCR-ABL/ABL <0.05%) and 38 pts (15%) had a complete molecular response (BCR-ABL undetectable). The 3-yr cumulative major molecular response rate was 55%, and complete molecular response rate 22%. Compared with a historical group of 131 similar patients in CML chronic phase post IFN failure treated with non-imatinib therapies, imatinib was associated with better 4-year survival rates (88%, versus 35% p<0.0001); this survival advantage for imatinib was confirmed by multivariate analysis (p<0.0001). Conclusions: The results with imatinib in CML chronic phase post IFN failure are improving and durable. Major and complete responses are now noted in a substantial proportion of patients with longer follow-up time. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis; Supergen

Activation of protein kinase A (PKA) by 8-Cl-cAMP as a novel approach for antileukaemic therapy.

Activation of PKA by cAMP agonists, such as 8-Cl-cAMP activation, selectively causes rapid apoptosis in v-abl transformed fibroblasts by inhibiting the Raf-1 kinase. Here we investigated whether 8-Cl-cAMP is useful for the treatment of chronic myelogenous leukaemia (CML), which is hallmarked by the expression of the p210bcr/abl oncogene. Autologous bone marrow transplantation is a feasible alternative for patients with no suitable donor, but hampered by the risk of relapse due to the persistence of leukaemia cells in the transplant. To study the effects of 8-Cl-cAMP on primary leukaemic cells, bone marrow cells (BMCs) from eight CML patients (one at diagnosis, three in chronic and four in accelerated phase) were treated. Ex vivo treatment of BMCs obtained in chronic phase of CML with 100 μM 8-Cl-cAMP for 24–48 h led to the selective purging of Philadelphia Chromosome (Ph1 chromosome) without toxic side effects on BMCs from healthy donors as measured by colony-forming unit (CFU) assays. BMCs from patients in accelerated phase showed selective, but incomplete elimination of Ph1 chromosome positive colony forming cells. The mechanism of 8-Cl-cAMP was investigated in FDCP-mix cells transformed by p210bcr/abl, a cell culture model for CML. The results showed that 8-Cl-cAMP reduced DNA synthesis and viability independent of Raf inhibition as Raf inhibitors had no effect. MEK inhibitors interfered with DNA synthesis, but not with viability. In summary, our results indicate that 8-Cl-cAMP could be useful to purge malignant cells from the bone marrow of patients with CML and certain other forms of leukaemias.

T(8;21)(q22;q22) in Blast Phase of Chronic Myelogenous Leukemia

The blast phase of chronic myelogenous leukemia (CML) frequently is associated with cytogenetic evidence of clonal evolution, defined as chromosomal aberrations in addition to the t(9;22)(q34;q11.2). We identified the t(8;21)(q22;q22) and other cytogenetic abnormalities by conventional cytogenetics and fluorescence in situ hybridization in 2 patients with t(9;22)-positive CML at the time of blast phase. The t(8;21), which typically is associated with a distinct subtype of de novo acute myeloid leukemia (AML) carrying the <italic>aml1/eto</italic> fusion gene, was accompanied by increased bone marrow myeloblasts (33%) in case 1 and extramedullary myeloid sarcoma in case 2, suggesting its possible role in disease progression. In case 1, the leukemic cells in aspirate smears had salmon-colored cytoplasmic granules, and immunophenotypic studies showed that the blasts expressed CD19. These findings suggest that the pathologic features of blast phase CML with the t(8;21) resemble those of de novo AML with the t(8;21).

Imatinib mesylate in the treatment of chronic myelogenous leukemia.

Imatinib mesylate binds to the inactive conformation of BCR-ABL tyrosine kinase, suppressing the Philadelphia chromosome-positive clone in chronic myelogenous leukemia (CML). Clinical studies of imatinib have yielded impressive results in the treatment of all phases of CML. With the higher rates of complete cytogenetic response with imatinib, molecular monitoring of disease has become mandatory in assessing response and determining prognosis. The practical aspects of the treatment of CML with imatinib are discussed. The emergence of imatinib resistance, albeit in a small percentage of patients, has prompted an evaluation of innovative treatment strategies.