Phase II study of the histone deacetylase inhibitor MGCD0103 in patients with previously treated chronic lymphocytic leukaemia

MGCD0103, an orally available class I histone deacetylase (HDAC) inhibitor, was examined for pre-clinical activity in chronic lymphocytic leukaemia (CLL). A phase II clinical trial was performed, starting at a dose of 85 mg/d, three times per week. Dose escalation to 110 mg or the addition of rituximab was permitted in patients without a response after two or more cycles. MGCD0103 demonstrated pre-clinical activity against CLL cells with a LC(50) (concentration lethal to 50%) of 0.23 micromol/l and increased acetylation of the HDAC class I specific target histone H3. Twenty-one patients received a median of two cycles of MGCD0103 (range, 0-12). All patients had previously received fludarabine, 33% were fludarabine refractory, and 71% had del(11q22.3) or del(17p13.1). No responses according to the National Cancer Institutes 1996 criteria were observed. Three patients received 110 mg and four patients received concomitant rituximab, with no improvement in response. Grade 3-4 toxicity consisted of infections, thrombocytopenia, anaemia, diarrhoea, and fatigue. HDAC inhibition was observed in six out of nine patients on day 8. Limited activity was observed with single agent MGCD0103 in high risk patients with CLL. Future investigations in CLL should focus on broad HDAC inhibition, combination strategies, and approaches to diminish constitutional symptoms associated with this class of drugs.

Phase I/II trial of AEG35156 X-linked inhibitor of apoptosis protein antisense oligonucleotide combined with idarubicin and cytarabine in patients with relapsed or primary refractory acute myeloid leukemia

PURPOSE

X-linked inhibitor of apoptosis protein (XIAP) is an inhibitor of caspases 3 and 9 which are overexpressed in acute myeloid leukemia (AML) and may contribute to chemoresistance. We report on a phase I/II trial of the XIAP antisense oligonucleotide AEG35156 in combination with reinduction chemotherapy.

PATIENTS AND METHODS

Twenty-four patients with rapidly relapsed or refractory AML were treated with escalating doses of AEG35156 (12 to 250 mg/m(2)) as an intravenous solution over 2 hours and 32 patients were treated with the highest planned dose of 350 mg/m(2) in combination with idarubicin and high-dose cytarabine reinduction chemotherapy. Correlative studies were conducted to determine the effects of AEG35156 on levels of XIAP mRNA.

RESULTS

Knockdown of XIAP mRNA during treatment increased with the dose of the antisense. All patients who received 350 mg/m(2) of AEG35156 had higher than 30% target knockdown with a median maximal knockdown of 90% (range, 48% to 100%). The overall response rate was higher among the patients receiving the highest dose of AEG35156. In this group, 15 (47%) of 32 patients achieved complete response (CR)/CR with incomplete platelet count recovery (CRp) compared with only one (4%) of 24 receiving 12 to 250 mg/m(2) AEG35156. Among the patients receiving 350 mg/m(2) of AEG35156 in combination with chemotherapy, 10 (91%) of 11 who were refractory to a single induction chemotherapy regimen achieved CR/CRp after reinduction with AEG35156 and chemotherapy. AEG35156 was well tolerated save for two cases of peripheral neuropathy in patients receiving multiple doses of AEG35156.

CONCLUSION

At the highest dose tested, AEG35156 knocks down its target and appears very effective when combined with chemotherapy in patients with AML refractory to a single induction regimen.

A phase I study of the pan bcl-2 family inhibitor obatoclax mesylate in patients with advanced hematologic malignancies

PURPOSE

The outcome of patients with refractory leukemia and myelodysplasia is poor, and new therapies are needed. The antiapoptotic proteins of the Bcl-2 family are overexpressed in these malignancies and are potential therapeutic targets. Therefore, we conducted a phase I clinical trial of the small-molecule pan-Bcl-2 inhibitor, obatoclax mesylate, in patients with refractory leukemia and myelodysplasia to assess its safety and define its optimal dose.

EXPERIMENTAL DESIGN

Forty-four patients with refractory leukemia or myelodysplasia were treated with obatoclax mesylate by continuous intravenous infusion at increasing doses and frequencies.

RESULTS

A total of 306 infusions of obatoclax mesylate were administered with a median of 5 infusions per patient. The study drug was well tolerated up to the highest dose planned without dose-limiting toxicity. Grade 1/2 central nervous system symptoms were the most common adverse events attributable to the study drug. One patient with acute myeloid leukemia with mixed lineage leukemia t(9;11) rearrangement achieved a complete remission, which lasted 8 months. Three of 14 patients with myelodysplasia showed hematologic improvement with RBC or platelet transfusion independence.

CONCLUSIONS

Obatoclax mesylate is well tolerated and these results support its further investigation in patients with leukemia and myelodysplasia.

Drug-resistant AML cells and primary AML specimens are killed by 111In-anti-CD33 monoclonal antibodies modified with nuclear localizing peptide sequences

Multidrug resistance (MDR) is a major challenge to the successful treatment of acute myeloid leukemia (AML). Our purpose was to determine whether (111)In-HuM195 anti-CD33 antibodies modified with peptides harboring nuclear localizing sequences (NLS) could kill drug-resistant AML cell lines and primary AML patient specimens expressing MDR transporters through the emission of Auger electrons.

METHODS

HuM195, M195, and irrelevant mouse IgG (mIgG) were conjugated to 10+/-3 NLS peptides and then labeled with (111)In by diethylenetriaminepentaacetic acid substitution to a specific activity of 1-8 MBq/microg. The binding affinity of HuM195 and M195 was determined for HL-60 and mitoxantrone-resistant HL-60-MX-1 cells. Nuclear localization of (111)In-NLS-HuM195, (111)In-NLS-M195, (111)In-HuM195, and (111)In-M195 was measured by subcellular fractionation. The antiproliferative effects of (111)In-NLS-HuM195, (111)In-NLS-M195, (111)In-HuM195, and (111)In-M195 (2.5-250 kBq/well) on HL-60 and HL-60-MX-1 were studied using the WST-1 assay. Clonogenic survival of HL-60 and HL-60-MX-1 leukemic cells and 10 primary AML specimens with MDR phenotype (assessed by flow cytometry) was determined after exposure for 3 h at 37 degrees C to 2.5-250 mBq/cell of (111)In-NLS-HuM195, (111)In-HuM195, or (111)In-NLS-mIgG. Clonogenic survival versus the amount of radioactivity incubated with the cells (mBq/cell) was plotted, and the mean lethal amount of radioactivity and the lower asymptote of the curve (plateau) were determined.

RESULTS

The (111)In-labeled anti-CD33 monoclonal antibodies HuM195 and M195 modified with NLS were efficiently routed to the nucleus of HL-60 cells and their mitoxantrone-resistant clone after CD33-mediated internalization. The following are the principal findings of our study: (111)In-NLS-HuM195 was more effective at killing HL-60 and HL-60-MX-1 cells than was (111)In-HuM195, a strong correlation between the specific activity of the (111)In-labeled radioimmunoconjugates and their cytotoxicity toward AML cells existed, and leukemic cells from patients were killed by (111)In-NLS-M195 or (111)In-M195, but the cytotoxic response among specimens was heterogeneous.

CONCLUSION

NLS conjugation enhanced the nuclear uptake and cytotoxicity of (111)In-HuM195 and (111)In-M195 toward drug-resistant AML cell lines as well as patient specimens expressing a diversity of MDR phenotypes, including Pgp-170, BCRP1, or MRP1 transporters. Targeted Auger electron radioimmunotherapy using (111)In-labeled anti-CD33 monoclonal antibodies modified with NLS may be able to overcome MDR and provide a means of treating chemotherapy-resistant myeloid leukemias in patients.

Adult precursor T-lymphoblastic leukemia/lymphoma with myeloid-associated antigen expression is associated with a lower complete remission rate following induction chemotherapy

Prognostic studies of T-cell lymphoblastic leukemia/lymphoma (T-ALL) have been performed in small patient cohorts with conflicting results. We systematically reviewed 67 adult T-ALL patients diagnosed and treated at our institute to identify clinical and pathologic prognostic factors. The median initial WBC was 21.3 x 10(9)/l. Blasts expressed at least one myeloid-associated antigen in 33%. Karyotypes were abnormal in 32% of the cases. Fifty-six of 64 patients (88%) achieved complete remission (CR). In univariate analysis, age, gender, initial WBC, CD10, CD34 and abnormal karyotype did not predict CR. Patients expressing at least one myeloid-associated antigen had a CR of 74% compared to 94% (p = 0.04) for those not expressing myeloid antigens. None of the above factors affected relapse-free or overall survival in this cohort. Our study indicates that expression of myeloid-associated antigens is associated with a lower CR rate in adult T-ALL and may be considered in risk stratification for induction chemotherapy.

Outcome of patients who develop acute leukemia or myelodysplasia as a second malignancy after solid tumors treated surgically or with strategies that include chemotherapy and/or radiation

BACKGROUND

Evaluation of therapeutic outcomes and risk factors was undertaken for patients with primary solid tumors (PST) developing acute leukemia or myelodysplasia (MDS) as a second malignancy.

METHODS

In all, 131 consecutive patients presenting to a single institution with leukemia or MDS after treatment for PST with surgery or chemotherapy/radiotherapy were examined. Management of the secondary acute leukemia and MDS consisted either of intensive therapy including allogeneic blood and marrow transplants or supportive measures.

RESULTS

The time from diagnosis of PST to development of acute leukemia or MDS, the cytogenetic profile of patients, and their survival were similar irrespective of PST therapy with surgery alone or strategies involving chemotherapy and/or radiation. The median survival of all 131 patients was 10.5 months with a 5-year survival of 15.6%. Induction therapy and/or transplantation resulted in a median survival of 13.6 months and a 5-year survival of 26.6% compared with 6.5 months and 2% with supportive measures. Subset analysis of transplant recipients revealed a median survival of 17.6 months and a 37.9% 5-year survival. Despite a significantly lower recurrence rate the survival of transplant recipients was not improved secondary to a higher treatment-related mortality (TRM) rate.

CONCLUSIONS

Patients developing acute leukemia or MDS after PST demonstrated similar cytogenetic profiles and clinical outcomes independent of the type of treatment. Survival was significantly better for patients able to undergo intensive therapy compared with supportive measures. The low recurrence rate for allograft recipients was consistent with a potent antileukemic effect that may translate into a survival benefit if TRM could be reduced.

Assessment of the downstream portion of the mitochondrial pathway of caspase activation in patients with acute myeloid leukemia

Most chemotherapeutic agents used in the treatment of acute myeloid leukemia (AML) induce apoptosis by triggering the mitochondrial pathway of caspase activation. To investigate the downstream portion of the mitochondrial pathway of caspase activation in patients with AML, cytosolic lysates were stimulated with cytochrome c and dATP and hydrolysis of Ac-DEVD-AFC by effector caspases was measured. Defects in the distal mitochondrial pathway were more common in samples from patients with AML that relapsed rapidly after induction chemotherapy compared to samples from treatment naïve patients. The incidence of blocked pathways did not differ based on response to induction chemotherapy, as even nonresponders generally had an intact pathway. When the distal mitochondrial pathway was blocked, defects were usually at the level of the effector caspases. Thus, functional defects in the distal portion of the mitochondrial pathway of caspase activation may help explain the nature of response and relapse after treatment.

The impact of acute myeloid leukemia and its treatment on quality of life and functional status in older adults

Although intensive chemotherapy (IC) may modestly improve survival compared to supportive care in older people with acute myeloid leukemia (AML), treatment may worsen quality of life (QOL) and functional status. We assessed QOL and functional status at baseline, 1 month, 4 months, and 6 months in 65 consecutive, English-speaking, patients age 60 or older with newly diagnosed AML. At baseline, functional status was high but QOL was negatively affected in global health and most QOL domains. Over time, QOL remained stable or improved in most patients and was generally similar between IC and non-IC groups. Basic activities of daily living (ADL) scores did not change over time, whereas instrumental ADL scores declined slightly regardless of treatment. Receiving IC does not appear to lead to worse QOL or functional status than more palliative approaches. This information may aid treatment discussions in older patients with AML.

Extramedullary infiltrates of AML are associated with CD56 expression, 11q23 abnormalities and inferior clinical outcome

We evaluated the frequency and prognostic significance of extramedullary infiltrates (EMI) at presentation of acute myeloid leukemia (AML) in adult patients. Of 331 cases with de novo AML, 101(30.5%) had extramedullary infiltrates at diagnosis. The extramedullary manifestations included: lymphadenopathy, splenomegaly, hepatomegaly, gingival hypertrophy, skin infiltrates and involvement of central nervous system (CNS). Patients with EMI had a high initial WBC count and a high proportion of M4/M5 morphological variants. The complete remission rate (CR) with induction chemotherapy was lower in patients with EMI (P=0.0077) and their overall survival was also inferior (P=0.0017). Flow cytometric evaluation of the surface antigens expressed by the leukemic blasts for CD34, TdT, HLADR, CD7, CD19 and CD56 found that only CD56 expression was associated with EMI. The association of CD56 expression with lymphadenopathy was statistically significant (P=0.035). Abnormal karyotypes were found in 50.6% of patients with EMI and 49.7% of patients without EMI. Only 11q23 abnormalities were associated with specific sites of EMI; lymphadenopathy (P=0.0111) and gingival hypertrophy (P=0.0016). Our study of adult AML patients demonstrates that EMI at diagnosis is associated with CD56 expression by leukemic blasts, 11q23 karyotypic abnormalities, low complete remission rate and poor overall survival.

The morphological subcategories of acute monocytic leukemia (M5a and M5b) share similar immunophenotypic and cytogenetic features and clinical outcomes

Acute monocytic leukemia (M5) is a subtype of acute myeloid leukemia (AML) with two distinct morphologic subcategories, M5a and M5b. We compared the immunophenotype, cytogenetics and clinical outcome of AML M5 with non-M5 AML and also compared M5a with M5b. One hundred and twelve M5 (76 M5a, 36 M5b) and 726 non-M5 cases were identified and treated on protocols at our institution. There were no significant differences in immunophenotype between M5a and M5b. Translocation 11q23 was the sole abnormality in 18.6% of M5 and 3.2% of non-M5 (p<0.001). Trisomy 8 was also more prevalent in M5 (16.9%) than in non-M5 (8.7%; p=0.03). There was no significant difference in karyotypes between M5a and M5b. The complete remission rate was 70% for AML M5 and 57% for non-M5 AML (p=0.03). There was no significant difference in median overall survival or disease free survival for patients with M5 versus non-M5, M5a versus M5b. Our data indicate that the prognosis of AML M5 is similar to non-M5 AML and that M5a and M5b do not differ in immunophenotype, cytogenetics or clinical outcome.

CD7 expression predicts poor disease free survival and post-remission survival in patients with acute myeloid leukemia and normal karyotype

AML patients with normal karyotype comprise the largest subgroup ( approximately 50%) but have a highly heterogeneous clinical course. By multi-parameter flow cytometry we analyzed CD7 expression along with other phenotypic markers in 185 patients with normal-karyotype AML. CD7 was expressed in 68 (37%) patients. CD7 expression was associated with younger age (P=0.024) but not with sex, WBC count, or extramedullary disease. Patients expressing CD7 had significant shorter disease free (DFS) and post-remission survivals (PRS) than patients without CD7 (DFS of 12 months versus 42 months, P=0.005; PRS of 15 months versus 33 months, P=0.013). We also found that expression of CD34 or HLA-DR was associated with lower CR rate (P=0.0007 and P=0.019, respectively) but did not affect DFS or OS. Furthermore, as for all AML patients, we demonstrated that in the normal karyotypic subgroup, patients with higher WBC counts (>50) and older age (>60 years) had lower CR rate (P=0.003 and P=0.0157, respectively) and shorter OS (P</=0.001 and P=0.007, respectively). Multivariate analysis of age, WBC, CD34, HLA-DR and CD7 showed that CD7 expression was an independent risk factor for DFS (P=0.01) and PRS (P=0.02).

A prospective, non-randomised phase 1-2 trial of VACOP-B with filgrastim support for HIV-related non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma (NHL) remains an important complication of associated HIV infection despite advances in antiretroviral therapy (ART), and the optimum chemotherapy regimen for this disease remains to be defined. A dose-escalation trial was performed to determine the maximum tolerated doses of etoposide and doxorubicin as part of the 12-week VACOP-B regimen, supported by filgrastim (r-metHuG-CSF). Patients with aggressive histology HIV-related NHL who were previously untreated with chemotherapy, and who had no active opportunistic infection were eligible for the study. Chemotherapy consisted of cyclophosphamide 350 mg/m2, vincristine 2 mg, bleomycin 10 U/m2; and prednisone 100 mg q2 days x 12 weeks, with increasing doses of doxorubicin 25-50 mg/m2 and etoposide 25-50 mg/m2 intravenously and 50-100 mg/m2 orally. Central nervous system prophylaxis (intrathecal cytarabine 50 mg x 4 doses), antifungal, and Pneumocystis carinii prophylaxis were used, and filgrastim was administered to prevent neutropenic complications. One dose level was expanded to permit the concomitant use of ART. Endpoints were determination of maximum tolerated dose of doxorubicin and etoposide, treatment tolerability, and survival. Forty-seven patients were enrolled, most with diffuse large-cell or immunoblastic NHL. Protocol-defined maximum tolerated dose was not reached and the limits of dose-limiting toxicity were not exceeded, even in patients receiving ART. Thirty-two cycles (4.9%) were delayed >6 days because of toxicity; 30 patients (64%) completed all 12 weeks of treatment. After completion of therapy, 14 patients had a complete response (30%), and 4 had a partial response (8%). Median time to progression was 9 months. At 42 months, progression-free survival was 25% and overall survival was 28%.

Fatigue in older adults with acute myeloid leukemia (AML): Predictors and impact on quality of life (QOL) and functional status

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Background: Fatigue is one of the most common and important symptoms in patients with cancer, yet little is known about predictors of fatigue or its impact on either QOL or functional status in older adults with AML. Methods: Patients aged 60 or older presenting with AML to an AML referral centre were enrolled at diagnosis. Fatigue and QOL were evaluated at baseline and at 1, 4, and 6 months. Questionnaires included the Functional Assessment of Cancer Therapy Anemia and Fatigue subscale (FACT-An) and the European Organization for the Research and Treatment of Cancer QLQ-C30. Correlations between FACT-An scores, predictor variables, and QOL domains were examined with Pearson correlation. Mixed effects modeling was used to examine changes in fatigue over time. Results: Between June 2003 and December 2005, 63 patients (mean age 72) were enrolled. Fatigue was the most common symptom and was of moderate severity in the majority of patients. Fatigue scores at baseline did not correlate with age, hemoglobin level, white blood cell count, or bone marrow blast percentage but correlated positively with depression scores. There were strong correlations (r=0.56 to 0.70, p<0.01) between fatigue scores and depression scores over time, and moderate to strong correlations (r=0.36 to 0.67, p<0.01) with both global QOL and all 5 QOL domains of the QLQ-C30 over time. Correlations were slightly weaker with functional status measures (r=0.25 to 0.76). There was a weak but inconsistent relationship between fatigue scores and change in hemoglobin over time. Fatigue scores did not improve over time regardless of treatment intent and were not better by 6 months among those achieving complete remission. Conclusions: Fatigue is the most common symptom in older adults with AML and is negatively correlated with QOL and functional status. There is a weak relationship with anemia but not with other markers of disease severity. Fatigue does not improve by 6 months even in those who achieve remission. Further studies are needed to identify potential intervention targets to improve fatigue in this population.

No significant financial relationships to disclose.

Nuclear localizing sequences promote nuclear translocation and enhance the radiotoxicity of the anti-CD33 monoclonal antibody HuM195 labeled with 111In in human myeloid leukemia cells

Our objective was to evaluate the toxicity of the anti-CD33 monoclonal antibody HuM195 modified with peptides (CGYGPKKKRKVGG) harboring the nuclear localizing sequence (NLS; underlined) of simian virus 40 large T antigen and labeled with (111)In against acute myeloid leukemia (AML) cells.

METHODS

HuM195 was derivatized with sulfosuccinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (sulfo-SMCC) to introduce maleimide groups for reaction with NLS-peptides and then conjugated with diethylenetriaminepentaacetic acid for labeling with (111)In. The immunoreactivity of NLS-HuM195 was evaluated by its ability to displace the binding of (111)In-HuM195 to HL-60 leukemia cells. Nuclear localization was measured in HL-60 cells by subcellular fractionation. The antiproliferative effects of (111)In-NLS-HuM195 and (111)In-HuM195 on HL-60, U937, or K562 cells with high, intermediate, or minimal CD33 expression, respectively, were studied. The survival of HL-60 cells or patient AML specimens treated with (111)In-NLS-HuM195 or (111)In-HuM195 was studied. Normal tissue toxicity was evaluated in BALB/c mice injected intravenously with of 3.7 MBq (22 microg) of (111)In-NLS-HuM195 or (111)In-HuM195.

RESULTS

NLS-HuM195 exhibited relatively preserved CD33 binding affinity (dissociation constant [K(d)] = 4.3 +/- 1.7 x 10(-9) mol/L to 6.9 +/- 1.3 x 10(-9) mol/L). Nuclear uptake increased from 10.5% +/- 0.5% for (111)In-HuM195 to 28.5% +/- 4.1% or 65.9% +/- 1.5% for (111)In-HuM195 substituted with 4 or 8 NLS-peptides, respectively. The inhibitory concentrations of 50% (IC(50)) and 90% (IC(90)) for HL-60 cells treated with (111)In-NLS-HuM195 were 37 kBq per 10(3) cells and 77-81 kBq per 10(3) cells, respectively. The IC(50) and IC(90) values for (111)In-HuM195 were 92 kBq per 10(3) cells and 203 kBq per 10(3) cells. Growth inhibition was correlated with the level of CD33 expression. The survival of HL-60 cells was reduced from 232 +/- 22 colonies (control) to 7 +/- 1 colonies with 1.48 mBq per cell of (111)In-NLS-HuM195; no colonies were found at 3.33 mBq per cell. The surviving fraction decreased >2-fold in 7 of 9 AML specimens treated with an excess of (111)In-NLS-HuM195 and >10-fold in 2 of these specimens. There were no decreases in body weight or hematologic parameters or increases in alanine aminotransferase or creatinine in mice administered 3.7 MBq (22 microg) of (111)In-NLS-HuM195 or (111)In-HuM195. There was no morphologic damage to the liver or kidneys.

CONCLUSION

We conclude that NLS-peptides routed (111)In-HuM195 to the nucleus of AML cells, where the emitted Auger electrons were lethal. (111)In-NLS-HuM195 is a promising targeted radiotherapeutic agent for AML.

Phase III Randomized Multicenter Study of a Humanized Anti-CD33 Monoclonal Antibody, Lintuzumab, in Combination With Chemotherapy, Versus Chemotherapy Alone in Patients With Refractory or First-Relapsed Acute Myeloid Leukemia

Purpose

Lintuzumab (HuM195) is an unconjugated humanized murine monoclonal antibody directed against the cell surface myelomonocytic differentiation antigen CD33. In this study, the efficacy of lintuzumab in combination with induction chemotherapy was compared with chemotherapy alone in adults with first relapsed or primary refractory acute myeloid leukemia (AML).

Patients and Methods

Patients with relapsed or primary resistant AML (duration of first response, zero to 12 months) were randomly assigned to receive either mitoxantrone 8 mg/m2, etoposide 80 mg/m2, and cytarabine 1 g/m2 daily for 6 days (MEC) in combination with lintuzumab 12 mg/m2, or MEC alone. Overall response, defined as the rate of complete remission (CR) and CR with incomplete platelet recovery (CRp), was the primary end point of the study, with additional analyses of survival time and toxicity.

Results

A total of 191 patients were randomly assigned from November 1999 to April 2001. The percent CR plus CRp with MEC plus lintuzumab was 36% v 28% in patients treated with MEC alone (P = .28). The overall median survival was 156 days and was not different in the two arms of the study. Apart from mild antibody infusion–related toxicities (fever, chills, and hypotension), no differences in chemotherapy-related adverse effects, including hepatic and cardiac dysfunction, were observed with the addition of lintuzumab to induction chemotherapy.

Conclusion

The addition of lintuzumab to salvage induction chemotherapy was safe, but did not result in a statistically significant improvement in response rate or survival in patients with refractory/relapsed AML.

Small-molecule XIAP inhibitors derepress downstream effector caspases and induce apoptosis of acute myeloid leukemia cells

We tested the effects of small-molecule XIAP antagonists based on a polyphenylurea pharmacophore on cultured acute myelogenous leukemia (AML) cell lines and primary patient samples. X-linked inhibitor of apoptosis protein (XIAP) antagonist N-[(5R)-6-[(anilinocarbonyl)amino]-5-((anilinocarbonyl){[(2R)-1-(4-cyclohexylbutyl)pyrrolidin-2-yl]methyl}amino)hexyl]-N-methyl-N'-phenylurea (1396-12), but not a structurally related control compound, induced apoptosis of primary leukemia samples with a lethal dose (LD50) of less than 10 microM in 16 of 27 (60%) samples. In contrast, XIAP antagonist 1396-12 was not lethal to the normal hematopoietic cells in short-term cytotoxicity assays. Response of primary AML specimens to XIAP inhibitor correlated with XIAP protein levels, with higher levels of XIAP associated with sensitivity. The XIAP antagonist 1396-12 induced activation of downstream caspases 3 and 7 prior to the activation of upstream caspase 8 and caspase 9. Apoptosis induction was also independent of B-cell lymphoma protein-2 (Bcl-2) or caspase 8, indicative of a downstream effect on apoptotic pathways. Thus, polyphenylurea-based XIAP antagonsists directly induce apoptosis of leukemia cells and AML patient samples at low micromolar concentrations through a mechanism of action distinct from conventional chemotherapeutic agents.

Hairy Cell Leukemia Variant With Features of Intrasinusoidal Bone Marrow Involvement

Hairy cell leukemia variant (HCL-V) is a rare lymphoproliferative disorder. We report a case of HCL-V with an intrasinusoidal pattern of bone marrow involvement without interstitial or diffuse infiltration that is typical of HCL and its variant. The peripheral blood and bone marrow aspirates demonstrated abnormal lymphoid cells with cytoplasmic projections that were weakly positive for tartrate-resistant acid phosphatase cytochemical staining. Immunostaining of the bone marrow biopsy specimen showed that these cells were strongly positive for CD20, located within bone marrow sinusoids, and weakly positive for DBA44. By flow cytometry, these cells were positive for CD19, CD20, CD11c, and CD103, exhibited λ light chain restriction, and were negative for CD25. The patient was initially diagnosed as having splenic lymphoma with villous lymphocytes (SLVL) or splenic marginal zone lymphoma (SMZL) (World Health Organization designation) and treated with fludarabine followed by splenectomy with simultaneous liver biopsy. The pathologic analysis of the spleen revealed infiltration of red pulp by the critical cells without white pulp involvement, which is characteristic of HCL and HCL-V but not of SLVL (SMZL). This case illustrates an atypical marrow presentation of HCL-V and emphasizes the need to correlate all clinical and pathologic data, including tissue biopsy, in reaching a diagnosis.

Role of all-trans-retinoic acid (ATRA) in the consolidation therapy of acute promyelocytic leukaemia (APL)

The role of all-trans-retinoic acid (ATRA) in the consolidation therapy of acute promyelocytic leukaemia (APL) is undefined at present. Between 1994 and 1999, we treated 38 newly diagnosed APL patients with ATRA and chemotherapy during the induction and consolidation. ATRA was given for 28 days each during the induction and 2 cycles of consolidation therapy. Chemotherapy consisted of daunorubicin and cytarabine. No maintenance therapy was given. ATRA was well-tolerated during consolidation therapy with no cases of retinoic acid syndrome. The 5-year overall and leukaemia-free survival of study patients was 82% (95% C.I. 70-95%) and 78% (95% C.I. 65-93%), respectively. These data are comparable to the studies that used prolonged maintenance with ATRA +/- chemotherapy. The role of ATRA during consolidation therapy of APL merits further investigation as this may allow shortening the overall duration of APL treatment.

Disease biology rather than age is the most important determinant of survival of patients ≥ 60 years with acute myeloid leukemia treated with uniform intensive therapy

BACKGROUND

The objectives of the current study were to evaluate the outcome of patients > or = 60 years with acute myeloid leukemia (AML) treated uniformly with high-dose daunorubicin containing induction and modified high-dose cytosine arabinoside containing postremission therapy, and to identify factors predictive of complete disease remission (CR) and survival.

METHODS

Between 1998 and 2002, the authors treated 117 newly diagnosed patients (acute promyelocytic leukemia excluded) with AML > or = 60 years (median, 67 years; range, 60-82 years). Karyotype (Medical Research Council classification) at diagnosis was categorized as good risk (n = 3), intermediate risk (n = 69), adverse risk (n = 26), and suboptimal/not done (n = 19). A normal karyotype was seen in 41 patients and 40 (34%) had secondary AML.

RESULTS

The outcome of induction included the following: CR, 62 (53%); early death, 5 (4%); death during hypoplasia, 14 (12%); and resistant disease, 36 (31%). The 3-year event-free (EFS) and overall survival (OS) rates were 9% (95% confidence interval [95% CI], 3-16%) and 17% (95% CI, 9-29%), respectively. In a univariate analysis, cytogenetics, lactate dehydrogenase level, leukocyte count, and performance status were the significant factors for EFS and OS. Age was not a significant prognostic factor for either CR or survival. In a multivariate model, adverse-risk cytogenetics, previous history of myelodysplastic syndrome or antecedent hematologic disorder, and high leukocyte count (> 30 x 10(9)/L) were independent adverse prognostic factors for survival. The impact of adverse karyotype on EFS and OS was time dependent and was observed after 50 and 150 days, respectively.

CONCLUSIONS

The authors concluded that candidacy for intensive therapy in older patients should be based on biologic features of disease and fitness, rather than on age.