Resilience in Older Adults Diagnosed With Cancer and Receiving Chemotherapy

BACKGROUND

Resilience is the capacity for physical and emotional recovery from stressful events like cancer diagnosis and treatment.

OBJECTIVES

The objectives of this study were to review existing literature to understand and illustrate ways to assess and manage resilience when providing holistic care to older adults with cancer.

METHODS

A review of the literature was conducted with a focus on assessment, management, and preservation of resilience in older adults with cancer.

FINDINGS

Interventions to support resilience include managing problems that occur in the areas of nutrition, exercise, social support, cognition, functional status, and emotion. Cell cycle arrest using pharmacologic agents may provide a novel proactive approach to protect resilience from deteriorating during chemotherapy to treat cancer. The oncology nurse can assess and manage resilience. which can lead to better treatment outcomes.

Outcomes of patients with chronic myelomonocytic leukaemia treated with non-curative therapies: a retrospective cohort study

BACKGROUND

Approval of hypomethylating agents in patients with chronic myelomonocytic leukaemia is based on trials done in patients with myelodysplastic syndromes. We aimed to investigate whether hypomethylating agents provide a benefit in subgroups of patients with chronic myelomonocytic leukaemia compared with other treatments.

METHODS

For this retrospective cohort study, data were retrieved between Nov 30, 2017, and Jan 5, 2019, from 38 centres in the USA and Europe. We included non-selected, consecutive patients diagnosed with chronic myelomonocytic leukaemia, who received chronic myelomonocytic leukaemia-directed therapy. Patients with acute myeloid leukaemia according to 2016 WHO criteria at initial diagnosis (ie, ≥20% blasts in the bone marrow or peripheral blood) or with unavailability of treatment data were excluded. Outcomes assessed included overall survival, time to next treatment, and time to transformation to acute myeloid leukaemia. Analyses were adjusted by age, sex, platelet count, and Chronic myelomonocytic leukaemia-Specific Prognostic Scoring System (CPSS). Patients were grouped by first received treatment with either hydroxyurea, hypomethylating agents, or intensive chemotherapy, and stratified by risk according to blast count, French-American-British subtype, CPSS, WHO 2016 subtype, and the eligibility criteria of the DACOTA trial (NCT02214407).

FINDINGS

949 patients diagnosed with chronic myelomonocytic leukaemia between April 13, 1981, and Oct 26, 2018, were included. Median follow-up was 23·4 months (IQR 11·5-42·3) from diagnosis and 16·2 months (6·6-31·6) from start of first-line treatment. 412 (43%) of 949 patients received hypomethylating agents as first treatment, 391 (41%) hydroxyurea, and 83 (9%) intensive chemotherapy. Adjusted median overall survival for patients treated with hydroxyurea versus hypomethylating agents was 15·6 months (95% CI 13·1-17·3) versus 20·7 months (17·9-23·4); hazard ratio (HR) 1·39 (1·17-1·65; p=0·0002) and 14·0 months (9·8-17·2) versus 20·7 months (17·9-23·4; HR 1·55 [1·16-2·05]; p=0·0027) for those treated with intensive chemotherapy versus hypomethylating agents. In patients with myeloproliferative chronic myelomonocytic leukaemia (myeloproliferative CMML), median overall survival was 12·6 months (10·7-15·0) versus 17·6 months (14·8-21·5; HR 1·38 [1·12-1·70]; p=0·0027) for patients treated with hydroxyurea versus hypomethylating agents, and 12·3 months (8·4-16·6) versus 17·6 months (14·8-21·5; HR 1·44 [1·02-2·03]; p=0·040) for intensive chemotherapy versus hypomethylating agents. Hypomethylating agents did not confer an overall survival advantage for patients classified as having lower-risk disease (ie, myelodysplastic chronic myelomonocytic leukaemia with <10% blasts, CMML-0, or lower-risk CPSS).

INTERPRETATION

These data suggest hypomethylating agents as the preferred therapy for patients with higher-risk chronic myelomonocytic leukaemia and those with myeloproliferative CMML. Our findings also suggest that CPSS is a valuable tool to identify patients who are most likely to benefit from hypomethylating agents. Further evidence from prospective cohorts would be desirable.

FUNDING

The Austrian Group for Medical Tumor Therapy.

Short- and long-term benefits of lenalidomide treatment in patients with lower-risk del(5q) myelodysplastic syndromes

In patients with transfusion-dependent, lower-risk, del(5q) myelodysplastic syndromes, lenalidomide effectively reduces red blood cell transfusion burden and acts as a disease-modifying agent, altering the natural history of the disease by suppressing the del(5q) clone. Hematologic and/or cytogenetic responses correlate with delayed acute myeloid leukemia progression and better overall survival.

The treatment of patients with myelodysplastic syndromes (MDS) begins with assessment of karyotype and risk. Lenalidomide is approved for the treatment of patients who have transfusion-dependent anemia due to lower-risk MDS with chromosome 5q deletion (del(5q)) with or without additional cytogenetic abnormalities, and isolated del(5q) only in the European Union. Mounting evidence suggests that lenalidomide is effective not only in reducing red blood cell (RBC) transfusion burden, but also in modifying the disease natural history by suppressing the malignant clone. Data discussed here from the pivotal phase 2 (MDS-003) and phase 3 (MDS-004) studies of lenalidomide demonstrate that lenalidomide treatment was associated with both short- and long-term benefits. These clinical benefits included high rates of RBC-transfusion independence (TI) with prolonged durations of response, high rates of cytogenetic response (CyR) associated with achievement of durable RBC-TI, no significant difference in rates of progression to acute myeloid leukemia (AML), and improvements in health-related quality of life (HRQOL). Achievement of RBC-TI and CyR with lenalidomide treatment was associated with extended survival and time to AML progression. Achievement of RBC-TI and hemoglobin response was additionally associated with HRQOL benefits. Recent data describing the impact of TP53 mutations and p53 expression on the prognosis of patients with del(5q) and the impact on response to lenalidomide are also discussed. The authors provide practical recommendations for the use of lenalidomide in patients with lower-risk del(5q) MDS.

The relationship of TP53 R72P polymorphism to disease outcome and TP53 mutation in myelodysplastic syndromes

Nonsynonymous TP53 exon 4 single-nucleotide polymorphism (SNP), R72P, is linked to cancer and mutagen susceptibility. R72P associations with specific cancer risk, particularly hematological malignancies, have been conflicting. Myelodysplastic syndrome (MDS) with chromosome 5q deletion is characterized by erythroid hypoplasia arising from lineage-specific p53 accumulation resulting from ribosomal insufficiency. We hypothesized that apoptotically diminished R72P C-allele may influence predisposition to del(5q) MDS. Bone marrow and blood DNA was sequenced from 705 MDS cases (333 del(5q), 372 non-del(5q)) and 157 controls. Genotype distribution did not significantly differ between del(5q) cases (12.6% CC, 38.1% CG, 49.2% GG), non-del(5q) cases (9.7% CC, 44.6% CG, 45.7% GG) and controls (7.6% CC, 37.6% CG, 54.8% GG) (P=0.13). Allele frequency did not differ between non-del(5q) and del(5q) cases (P=0.91) but trended towards increased C-allele frequency comparing non-del(5q) (P=0.08) and del(5q) (P=0.10) cases with controls. Median lenalidomide response duration increased proportionate to C-allele dosage in del(5q) patients (2.2 (CC), 1.3 (CG) and 0.89 years (GG)). Furthermore, C-allele homozygosity in del(5q) was associated with prolonged overall and progression-free survival and non-terminal interstitial deletions that excluded 5q34, whereas G-allele homozygozity was associated with inferior outcome and terminal deletions involving 5q34 (P=0.05). These findings comprise the largest MDS R72P SNP analysis.

Extended survival and reduced risk of AML progression in erythroid-responsive lenalidomide-treated patients with lower-risk del(5q) MDS

Lenalidomide is the approved treatment for patients with red blood cell (RBC) transfusion-dependent lower-risk myelodysplastic syndromes (MDS) and chromosome 5q deletion (del(5q)). We report the long-term outcomes (median follow-up 3.2 years) in patients treated with lenalidomide in the MDS-003 trial. RBC transfusion independence (TI) ≥ 8 weeks was achieved in 97 of 148 treated patients (65.5%), with a median response duration of 2.2 years. Partial or complete cytogenetic response was achieved by 63 of 88 evaluable patients (71.6%). Median overall survival (OS) was longer in patients achieving RBC-TI ≥ 8 weeks (4.3 vs 2.0 years in non-responders; P<0.0001) or cytogenetic response (4.9 vs 3.1 years in non-responders; P=0.010). Time to acute myeloid leukemia (AML) progression was longer in patients achieving RBC-TI ≥ 8 weeks or any cytogenetic response versus non-responders (P=0.001 and P=0.0002, respectively). In a landmark multivariate analysis, RBC-TI ≥ 8 weeks was associated with prolonged OS (P<0.001) and a trend toward reduced relative risk of AML progression (P=0.080). Among these lower-risk MDS patients with del(5q), lenalidomide was associated with prolonged RBC-TI and cytogenetic responses, which were linked to improved OS and reduced risk of AML progression.

Multiple mechanisms deregulate EZH2 and histone H3 lysine 27 epigenetic changes in myeloid malignancies

Polycomb repressive complex 2 (PRC2) is involved in trimethylation of histone H3 lysine 27 (H3K27), chromatin condensation and transcriptional repression. The silencing function of PRC2 complex is mostly attributed to its intrinsic activity for methylating H3K27. Unlike in B-cell lymphomas, enhancer of zeste homolog 2 (EZH2) mutations in myeloid malignancies are inactivating/hypomorphic. When we assessed the mutational status in myeloid malignancies (N=469 cases examined), we found EZH2 and EED/SUZ12 mutations in 8% and 3.3% of cases, respectively. In addition to mutant cases, reduced EZH2 expression was also found in 78% cases with hemizygous deletion (-7/del7q cases involving EZH2 locus) and 41% of cases with diploid chromosome 7, most interestingly cases with spliceosomal mutations (U2AF1/SRSF2 mutations; 63% of cases). EZH2 mutations were characterized by decreased H3K27 trimethylation and increased chromatin relaxation at specific gene loci accompanied by higher transcriptional activity. One of the major downstream target is HOX gene family, involved in the regulation of stem cell self-renewal. HOXA9 was found to be overexpressed in cases with decreased EZH2 expression either by EZH2/spliceosomal mutations or because of -7/del7q. In summary, our results suggest that loss of gene repression through a variety of mutations resulting in reduced H3K27 trimethylation may contribute to leukemogenesis.

Naive T-cells in myelodysplastic syndrome display intrinsic human telomerase reverse transcriptase (hTERT) deficiency

Telomeres are specialized structures providing chromosome integrity during cellular division along with protection against premature senescence and apoptosis. Accelerated telomere attrition in patients with myelodysplastic syndrome (MDS) occurs by an undefined mechanism. Although the MDS clone originates within the myeloid compartment, T-lymphocytes display repertoire contraction and loss of naive T-cells. The replicative lifespan of T-cells is stringently regulated by telomerase activity. In MDS cases, we show that purified CD3+ T-cells have significantly shorter telomere length and reduced proliferative capacity upon stimulation compared with controls. To understand the mechanism, telomerase enzymatic activity and telomerase reverse transcriptase (hTERT), gene expression were compared in MDS cases (n=35) and healthy controls (n=42) within different T-cell compartments. Telomerase activity is greatest in naive T-cells illustrating the importance of telomere repair in homeostatic repertoire regulation. Compared with healthy controls, MDS cases had lower telomerase induction (P<0.0001) that correlated with significantly lower hTERT mRNA (P<0.0001), independent of age and disease stratification. hTERT mRNA deficiency affected naive but not memory T-cells, and telomere erosion in MDS occurred without evidence of an hTERT-promoter mutation, copy number variation or deletion. Telomerase insufficiency may undermine homeostatic control within the hematopoietic compartment and promote a change in the T-cell repertoire in MDS.

A phase Ib study of vosaroxin, an anticancer quinolone derivative, in patients with relapsed or refractory acute leukemia

This study of vosaroxin evaluated dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), pharmacokinetics (PK), clinical activity and pharmacodynamics in relapsed/refractory leukemia. Dosing was weekly (days 1, 8 and 15) or twice weekly (days 1, 4, 8 and 11). Seventy-three treated patients had a median age of 65 years, 85% had acute myeloid leukemia and 78% had refractory disease. Weekly schedule: 42 patients received 18-90 mg/m(2); MTD was 72 mg/m(2). Twice-weekly schedule: 31 patients received 9-50 mg/m(2); MTD was 40 mg/m(2). DLT was stomatitis; primary non-hematologic toxicity was reversible gastrointestinal symptoms and febrile neutropenia. Thirty-day all-cause mortality was 11%. Five patients had complete or incomplete remissions; median duration was 3.1 months. A morphologic leukemia-free state (bone marrow blast reduction to <5%) occurred in 11 additional patients. Antileukemic activity was associated with total dose or weekly time above 1 μmol/l plasma vosaroxin concentration (P<0.05). Vosaroxin exposure was dose proportional over 9-90 mg/m(2). The average terminal half-life was ~25 h and clearance was non-renal. No induction or inhibition of vosaroxin metabolism was evident. Vosaroxin-induced DNA damage was detected as increased intracellular γH2AX. Vosaroxin had an acceptable safety profile, linear PK and encouraging clinical activity in relapsed/refractory leukemia.

Altered naive and memory CD4+ T-cell homeostasis and immunosenescence characterize younger patients with myelodysplastic syndrome

Response to immunosuppressive therapy (IST) in younger patients with myelodysplastic syndrome (MDS) has been linked to a T-cell-dominant autoimmune process that impairs hematopoiesis. Analysis of the age-adjusted CD4:CD8 ratio in 76 MDS patients compared with 54 healthy controls showed that inadequate CD4+, rather than expansion of CD8+ T cells, was associated with a lower ratio in a group that included both lower and higher risk MDS patients defined by the International Prognostic Scoring System. In younger MDS patients, naive and memory phenotypes defined by CD45RA and CD62L display showed depletion of naive CD4+ and CD8+ T cells, suggesting a possible relationship to IST responsiveness. To determine the correlation between T-cell subset distribution, T-cell turnover and autoimmunity, a cohort of 20 patients were studied before and after IST. The CD4:CD8 ratio correlated inversely with the proliferative T-cell index before treatment in IST-responsive patients, suggesting that proliferation may be linked to accelerated CD4+ T-cell turnover and hematopoietic failure. Our data show seminal findings that both CD4+ and CD8+ T-cell subsets are dysregulated in MDS. Association between these T-cell defects and response to IST suggests that aberrant T-cell homeostasis and chronic activation are critical determinants influencing autoimmune hematopoietic suppression in younger patients.

Azacitidine prolongs overall survival and reduces infections and hospitalizations in patients with WHO-defined acute myeloid leukaemia compared with conventional care regimens: an update

Azacitidine (AZA), as demonstrated in the phase III trial (AZA-001), is the first MDS treatment to significantly prolong overall survival (OS) in higher risk MDS pts ((2007) Blood110 817). Approximately, one-third of the patients (pts) enrolled in AZA-001 were FAB RAEB-T (≥20–30% blasts) and now meet the WHO criteria for acute myeloid leukaemia (AML) ((1999) Blood17 3835). Considering the poor prognosis (median survival <1 year) and the poor response to chemotherapy in these pts, this sub-group analysis evaluated the effects of AZA versus conventional care regimens (CCR) on OS and on response rates in pts with WHO AML.

The effects of continued azacitidine treatment cycles on response in higher risk patients with myelodysplastic syndromes: an update

The international, phase III, multi-centre AZA-001 trial demonstrated azacitidine (AZA) is the first treatment to significantly extend overall survival (OS) in higher risk myelodysplastic syndromes (MDS) patients (Fenaux (2007) Blood110 817). The current treatment paradigm, which is based on a relationship between complete remission (CR) and survival, is increasingly being questioned (Cheson (2006) Blood108 419). Results of AZA-001 show CR is sufficient but not necessary to prolong OS (List (2008) Clin Oncol26 7006). Indeed, the AZA CR rate in AZA-001 was modest (17%), while partial remission (PR, 12%) and haematological improvement (HI, 49%) were also predictive of prolonged survival. This analysis was conducted to assess the median number of AZA treatment cycles associated with achievement of first response, as measured by IWG 2000-defined CR, PR or HI (major + minor). The number of treatment cycles from first response to best response was also measured.

Evolving trends in the treatment of low-risk myelodysplastic syndromes: immunomodulation and beyond?9th European Hematology Association Congress Geneva, Switzerland, 10?13 June 2004

The 9th European Hematology Association Congress, held in Geneva, Switzerland, from 10 through 13 June 2004, offered a number of educational programmes that focused on myelodysplastic syndromes (MDS). This report will summarize the material presented at the educational symposium entitled 'Evolving Trends in the Treatment of Low-Risk MDS: Immunomodulation and Beyond'. The overview of the presentations includes a comparative review of the classification systems for MDS; a discussion of treatment strategies and management issues for patients in lower risk disease categories; a description of a novel class of immunomodulators, the IMiDs((R)), and a presentation of updated data from clinical trials of the IMiD compound, lenalidomide, in the treatment of MDS.

Prevalence and clinical association of clonal T-cell expansions in Myelodysplastic Syndrome

Selected patients with Myelodysplastic Syndromes (MDS) are responsive to immunosuppressive therapy, suggesting that hematopoietic suppressive T cells have a pathogenic role in ineffective hematopoiesis. We assessed T-cell receptor (TCR) clonality through combined flow cytometry and molecular analysis of the complementarity determining region (CDR)-3 of the T-cell receptor-Vbeta gene. We identified clonal T cells in 50% of MDS patients (n=52) compared to 5% of age-matched normal controls (n=20). The presence of T-cell clones was not associated with features linked previously to immunosuppression response, including WHO diagnostic category, karyotype, marrow cellularity, IPSS category, sex or age <or=60. Using flow cytometry to identify expanded Vbeta-families, we found that T cells showed greater expansion in the bone marrow compared with peripheral blood, and were characterized as CD8(+)/CD57(+)/CD28(-) effector T cells. Expanded effector T cell were CD62L negative and expressed the natural killer C-lectin-family receptor NKG2D and CD244 (2B4). We conclude that clonal T-cell expansion is common among all MDS prognostic subgroups.

Phase 1 study of PTK787/ZK 222584, a small molecule tyrosine kinase receptor inhibitor, for the treatment of acute myeloid leukemia and myelodysplastic syndrome

PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.

Epigenomic changes during leukemia cell differentiation: analysis of histone acetylation and cytosine methylation using CpG island microarrays

Dysregulation of epigenetic control is an important participant in carcinogenesis. The PML/RAR alpha translocation in acute promyelocytic leukemia (APL) is an example where the resultant fusion protein recruits histone deacetylase complexes to target genes resulting in their inappropriate transcriptional repression. All-trans-retinoic acid (ATRA) acts as a ligand that relieves this repression and produces an epigenetic transcriptional reprogramming of the cancer cell. CpG island microarrays were used to analyze the DNA methylation and histone acetylation state of the human APL cell line NB4 before and after differentiation with ATRA as well as normal peripheral blood mononuclear cells (PBMC). Over 70 CpG islands within 1 kb of transcription start of a known gene are aberrantly methylated in NB4 cells compared with PBMC; however, no changes in cytosine methylation were detected following ATRA-induced differentiation. With respect to histone H4 acetylation, over 100 single-copy CpG islands within 1 kb of transcription start of a known human gene became hyperacetylated following ATRA-induced differentiation. One CpG island was aberrantly methylated in NB4 cells, but became hyperacetylated and was induced following ATRA treatment and was associated with the HoxA1 gene, suggesting it may be a target gene of ATRA in APL. In addition to single-copy sequences, a selective increase in acetylation was detected in satellite DNA when compared with other high-copy sequences, such as Alu or rDNA. In summary, ATRA stimulates complex epigenomic changes during leukemic cell differentiation, and monitoring these changes may help to identify new targets of epigenetic dysfunction.

Vascular endothelial growth factor signaling pathway as an emerging target in hematologic malignancies

Angiogenesis is important in a variety of physiologic and pathologic disorders. It is a central element in embryogenesis, ovulation, wound healing, diabetic retinopathy, and rheumatoid arthritis and in the establishment and spread of malignant tumors. Angiogenic factors include direct angiogens, indirect angiogens, and integrins. Direct angiogens stimulate the formation of new blood vessels directly. Indirect angiogens promote neovascular formation by paracrine stimulation of direct angiogens. Integrins mediate interactions between the developing vessels and components of the extracellular matrix. Vascular endothelial growth factor (VEGF) is a principal direct angiogen. By binding to 1 of 3 receptors (VEGFR-1, -2, or -3), it influences vasculogenesis during embryogenesis, physiologic and neoplastic angiogenesis, and lymphangiogenesis. Although the importance of angiogenesis in solid tumors has been recognized for some time, its exact significance in hematologic malignancies is less clear. Evidence now suggests that VEGF has a major role in the development and progression of hematologic malignancies such as acute leukemia, chronic leukemia, myelodysplasia, non-Hodgkin's lymphoma, and multiple myeloma. Potential therapeutic interventions to interrupt the VEGF signaling pathway of malignancy include antibodies that neutralize the growth factor and small molecules that inhibit the receptor tyrosine kinase activity of VEGF receptors.

Benefit of cyclosporine modulation of drug resistance in patients with poor-risk acute myeloid leukemia: a Southwest Oncology Group study

Cyclosporine A (CsA) inhibits P-glycoprotein (Pgp)-mediated cellular export of anthracyclines at clinically achievable concentrations. This randomized controlled trial was performed to test the benefit of CsA addition to treatment with cytarabine and daunorubicin (DNR) in patients with poor-risk acute myeloid leukemia (AML). A total of 226 patients were randomly assigned to sequential treatment with cytarabine and infusional DNR with or without intravenous CsA. Remitting patients received one course of consolidation chemotherapy that included DNR with or without CsA as assigned during induction. Addition of CsA significantly reduced the frequency of resistance to induction chemotherapy (31% versus 47%, P =.0077). Whereas the rate of complete remission was not significantly improved (39% versus 33%, P =.14), relapse-free survival (34% versus 9% at 2 years, P =.031) and overall survival (22% versus 12%, P =.046) were significantly increased with CsA. The effect of CsA on survival was greatest in patients with moderate or bright Pgp expression (median 12 months with CsA versus 4 months for controls) compared to patients with absent or low Pgp expression (median 6 months in both arms). The frequency of induction deaths was 15% with CsA and 18% in controls. Steady-state serum concentrations of DNR (P =.0089) and daunorubicinol (P <.0001) were significantly higher in CsA-treated patients. Survival (P =.0003) and induction response (P =.028) improved with increasing DNR concentration in CsA-treated patients but not in controls, suggesting a targeted interaction by CsA to enhance anthracycline cytotoxicity. These results indicate that addition of CsA to an induction and consolidation regimen containing infusional DNR significantly reduces resistance to DNR, prolongs the duration of remission, and improves overall survival in patients with poor-risk AML.

KG-1 and KG-1a model the p15 CpG island methylation observed in acute myeloid leukemia patients

p15 and p16 are tumor suppressor genes that have 5' CpG islands and both are subject to hypermethylation associated with their transcriptional inactivation in hematological malignancies. In this study, we used sodium bisulfite sequencing to obtain a complete map of the 5-methylcytosine status of 80 CpGs covering approximately 900 bp in the 5' p15 CpG island, and 53 CpGs covering approximately 700 bp in the 5' p16 CpG island in the hematopoietic cell lines HL60, KG-1, and KG-1a, two normal human bone marrow samples (NBM), and eight cytosine arabinoside (ara-C)-resistant adult acute myeloid leukemia (AML) patients. We found methylation of the p15 CpG island in 75% of the AML cases studied spread throughout the 5' region analyzed but only minimal methylation of p15 in NBM. Further, the p16 CpG island was not aberrantly methylated in NBM or the eight AML patients studied. Two distinct modes of p15 methylation in AML were identified, variegated and complete. Interestingly, KG-1 and KG-1a model the methylation of p15 observed in AML, where KG-1 methylation is variegated and KG-1a methylation is complete. Both KG-1 and KG-1a had no detectable p15 mRNA or protein. These results demonstrate that rather than continuous increases in p15 methylation, surprisingly two punctuated modes of aberrant p15 methylation, variegated and complete, were observed in vitro and in vivo. Thus aberrant methylation of tumor suppressor genes is not a binary switch but in the case of p15 occurs in two independent and stable states.

Phase I/II study of the P-glycoprotein modulator PSC 833 in patients with acute myeloid leukemia

PURPOSE

To determine the maximum-tolerated dose, pharmacokinetic interaction, and activity of PSC 833 compared with daunorubicin (DNR) and cytarabine in patients with poor-risk acute myeloid leukemia.

PATIENTS AND METHODS

Patients received ara-C 3 g/m(2)/d on 5 consecutive days, followed by an IV loading dose of PSC 833 (1.5 mg/kg) and an 84-hour continuous infusion escalating from 6, 9, or 10 mg/kg/d. Daunorubicin was administered as a 72-hour continuous infusion at 34 or 45 mg/m2/d [corrected]. Responding patients received consolidation chemotherapy with DNR pharmacokinetics performed without PSC-833 on day 1, and with PSC-833 on day 4. Response was correlated with expression of P-glycoprotein and lung resistance protein (LRP), and in vitro sensitization of leukemia progenitors to DNR cytotoxicity by PSC 833.

RESULTS

All 43 patients are assessable for toxicity and response. Grade 3 or greater hyperbilirubinemia (70%) was the only dose-dependent toxicity. Four patients (9%) succumbed to treatment-related complications. Twenty-one patients (49%) achieved a complete remission or restored chronic phase, including 10 of 20 patients treated at the maximum-tolerated dose of 10 mg/kg/d of PSC-833 and 45 mg/m(2) of DNR. The 95% confidence interval for complete response was 33.9% to 63.7%. Administration of PSC 833 did not alter the mean area under the curve for DNR, although clearance decreased approximately two-fold (P =.04). Daunorubicinol clearance decreased 3.3-fold (P =.016). Remission rates were not effected by mdr-1 expression, but LRP overexpression was associated with chemotherapy resistance.

CONCLUSION

Combined treatment with infused PSC 833 and DNR is well tolerated and has activity in patients with poor risk acute myeloid leukemia. Administration of PSC 833 delays elimination of daunorubicinol, but yields variable changes in DNR systemic exposure.

Chemotherapy resistance in acute myeloid leukaemia

The development of refractory disease in acute myeloid leukaemia (AML) is frequently associated with the expression of one or several multidrug resistance (MDR) genes. MDR1, MRP1 and LRP have been identified as important adverse prognostic factors in AML. Recently it has become possible to reverse clinical multidrug resistance by blocking P-glycoprotein-mediated drug efflux. The potential relevance of MDR and new approaches to treat refractory disease, are discussed.

Vascular endothelial cell growth factor is an autocrine promoter of abnormal localized immature myeloid precursors and leukemia progenitor formation in myelodysplastic syndromes

Vascular endothelial growth factor (VEGF) is a potent angiogenic peptide with biologic effects that include regulation of hematopoietic stem cell development, extracellular matrix remodeling, and inflammatory cytokine generation. To delineate the potential role of VEGF in patients with myelodysplastic syndrome (MDS), VEGF protein and receptor expression and its functional significance in MDS bone marrow (BM) were evaluated. In BM clot sections from normal donors, low-intensity cytoplasmic VEGF expression was detected infrequently in isolated myeloid elements. However, monocytoid precursors in chronic myelomonocytic leukemia (CMML) expressed VEGF in an intense cytoplasmic pattern with membranous co-expression of the Flt-1 or KDR receptors, or both. In situ hybridization confirmed the presence of VEGF mRNA in the neoplastic monocytes. In acute myelogenous leukemia (AML) and other MDS subtypes, intense co-expression of VEGF and one or both receptors was detected in myeloblasts and immature myeloid elements, whereas erythroid precursors and lymphoid cells lacked VEGF and receptor expression. Foci of abnormal localized immature myeloid precursors (ALIP) co-expressed VEGF and Flt-1 receptor, suggesting autocrine cytokine interaction. Antibody neutralization of VEGF inhibited colony-forming unit (CFU)-leukemia formation in 9 of 15 CMML and RAEB-t patient specimens, whereas VEGF stimulated leukemia colony formation in 12 patients. Neutralization of VEGF activity suppressed the generation of tumor necrosis factor-alpha and interleukin-1beta from MDS BM-mononuclear cells and BM-stroma and promoted the formation of CFU-GEMM and burst-forming unit-erythroid in methylcellulose cultures. These findings indicate that autocrine production of VEGF may contribute to leukemia progenitor self-renewal and inflammatory cytokine elaboration in CMML and MDS and thus provide a biologic rationale for ALIP and its adverse prognostic relevance in high-risk MDS.

Rational approaches to design of therapeutics targeting molecular markers

This paper introduces novel therapeutic strategies focusing on a molecular marker relevant to a particular hematologic malignancy. Four different approaches targeting specific molecules in unique pathways will be presented. The common theme will be rational target selection in a strategy that has reached the early phase of human clinical trial in one malignancy, but with a much broader potential applicability to the technology. In Section I Dr. Richard Klasa presents preclinical data on the use of antisense oligonucleotides directed at the bcl-2 gene message to specifically downregulate Bcl-2 protein expression in non-Hodgkin's lymphomas and render the cells more susceptible to the induction of apoptosis. In Section II Dr. Alan List reviews the targeting of vascular endothelial growth factor (VEGF) and its receptor in anti-angiogenesis strategies for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). In Section III Dr. Bruce Cheson describes recent progress in inhibiting cell cycle progression by selectively disrupting cyclin D1 with structurally unique compounds such as flavopiridol in mantle cell lymphoma as well as describing a new class of agents that affect proteasome degradation pathways.

A randomized placebo-controlled trial of lisofylline in HLA-identical, sibling-donor, allogeneic bone marrow transplant recipients. The Lisofylline Marrow Transplant Study Group

The purpose of the study was to evaluate the effect of lisofylline (LSF) on engraftment, regimen-related toxicities (RRT), and mortality in patients undergoing allogeneic bone marrow transplantation (BMT). We performed a multicenter, randomized placebo-controlled trial in 60 patients with hematologic malignancies receiving BMT from HLA-identical sibling donors. Patients were randomized to receive either placebo, 2 mg/kg LSF or 3 mg/kg LSF every 6 h, beginning before conditioning and continuing to day 21 or hospital discharge. Treatment groups were balanced with respect to conditioning regimen and disease stage. However, significantly more patients in the 2 mg/kg LSF group were at high risk for RRT due to performance status >/=1, age >/=40 years, and prior exposure to CMV. Nausea and vomiting were the only adverse events observed in a higher proportion of LSF-treated patients that led to study withdrawal in six of 42 patients (14%). The times to neutrophil recovery to >/=500/microl and platelet recovery (>20 000/microl) were not improved by LSF treatment. Nevertheless, no patient who received treatment with 3 mg/kg LSF developed a documented infection between day 0 and 35 or had a serious or fatal infection between day 0 and 100 (P = 0.003 vs placebo for both). The day-100 survival rate was also significantly improved in the 3 mg/kg LSF group (89%), compared with either the 2 mg/kg LSF (48%) or placebo (61%) groups (log-rank test, 3 mg/kg LSF vs placebo, P = 0. 026). We conclude that treatment with LSF 3 mg/kg reduced the incidence of infections and improved 100-day survival in patients receiving related-donor allogeneic bone marrow transplantation. Bone Marrow Transplantation (2000) 25, 283-291.

Use of amifostine in hematologic malignancies, myelodysplastic syndrome, and acute leukemia

The phosphorylated thiol amine, amifostine (Ethyol; Alza Pharmaceuticals, Palo Alto, CA/US Bioscience, West Conshohocken, PA), is a cytoprotective agent for cisplatin-based chemotherapy. Recent investigations have given rise to new potential applications of amifostine in hematologic malignancies. Amifostine appears to exert a sustained mitogenic effect in primitive hematopoietic progenitors that results in a significant increase in colony-forming capacity. Amifostine also retards cell loss and delays commitment to apoptosis initiated by cytokine deprivation, suggesting that amifostine has trophic effects similar to the hematopoietic cytokines. The abilities to prolong progenitor survival and to delay apoptosis under conditions of cellular stress make amifostine an attractive agent for investigation in bone marrow failure states. Amifostine promotes more effective hematopoiesis in patients with myelodysplastic syndrome, although additional investigation is needed to further define the optimal dose and schedule of administration. Furthermore, amifostine may selectively enhance the cytotoxicity of chemotherapeutic agents in leukemia progenitors. When the sensitivity of leukemic and normal progenitors to mafosfamide was evaluated with and without amifostine pretreatment, amifostine effectively protected normal myeloid and erythroid progenitors while increasing leukemic cell kill. Thus, amifostine represents a unique agent with promising potential for therapeutic application in hematologic malignancies. Further investigation is needed to define its role in clinical practice.

Limited erythropoietic response to combined treatment with recombinant human interleukin 3 and erythropoietin in myelodysplastic syndrome

Twenty-two patients with myelodysplastic syndrome were treated with combined recombinant human erythropoietin and recombinant human interleukin 3 (rHuIL-3). All 22 patients were evaluable for toxicity and 21/22 for response. Thirteen patients (62%) required rHuIL-3 dose reduction because of toxicity. Nineteen experienced a 50% or greater rise in neutrophil count. Of seven patients with initial platelet counts of > 100,000, three experienced increases of > 15,000/ml while an equal number had a comparable decline. Five patients (21%) experienced a significant rise in reticulocyte count, and two transfusion-dependent patients experienced a significant decrease in transfusions. Erythroid burst-forming units were increased by > or = 50% in nine of 11 patients after combined therapy. Similar changes were seen in multipotential colony-forming units. Clinical responses were comparable to results obtained with epo alone while toxicities due to IL-3 were significant.

Pharmacological differentiation and anti-apoptotic therapy in myelodysplastic syndromes

The haematological diversity of myelodysplastic syndromes (MDS) mandates that therapeutic strategies for this disease be guided by an understanding of the disease biology. Insights into the pathobiology of this disease have given rise to novel treatment strategies which exploit basic biological disturbances. Myelodysplastic bone marrow progenitors from patients with low leukaemia burden display an accelerated senescence phenotype which is characterised by impaired response to trophic signals and premature apoptotic death of primitive haematopoietic progenitors. Elaboration of aptogenic cytokines such as TNF-alpha and IL-1beta may reinforce this sequence by up-regulating cellular expression of fas ligand and its cognate receptor, suppressing responsiveness to growth factor stimulation, and accelerating apoptotic cell death. Inactivation of p15 or other tumour suppressor genes antedate disease progression and the emergence of blast populations with reduced capacity for fas mediated cell death. Herein we review the current understanding of the pathobiology of MDS and promising strategies for therapeutic intervention.

Selective variegated methylation of the p15 CpG island in acute myeloid leukemia

Both p15 and p16 are tumor suppressor genes that have 5' CpG islands; aberrant cytosine methylation of these islands has been associated with silencing of their expression. Deoxycytidine kinase (dCK) converts prodrugs to their cytotoxic form, has a 5' CpG island and is a candidate gene for inactivation by hypermethylation. In our study, we used sodium bisulfite sequencing to generate high resolution maps of 5-methylcytosine in the CpG islands associated with p15, p16 and dCK in normal human bone marrow (BM), peripheral blood lymphocytes (PBL) and cytosine arabinoside (ara-C)-resistant acute myeloid leukemia (AML) patients, and established human hematopoietic tumor cell lines. In normal cells the p15, p16 and dCK CpG islands were largely unmethylated. The p16 and dCK CpG islands were also unmethylated in the 8 AML specimens. In contrast, the p15 CpG island was aberrantly methylated in 6 of the 8 AML specimens. Furthermore, bisulfite sequencing revealed that the p15 CpG island is heterogeneously methylated in AML, with large intra-individual and inter-individual variability.

Amifostine stimulates formation of multipotent and erythroid bone marrow progenitors

Amifostine (WR-2721, Ethyol) is a phosphorylated aminothiol that affords broad cytoprotection from the myelosuppressive effects of antineoplastics. To further characterize its hematopoietic activities, we investigated the effects of amifostine and its dephosphorylated metabolite, WR1065, on the in vitro growth of human bone marrow progenitors. Preincubation exposure to amifostine or WR1065 stimulated the growth of colony-forming units granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM) and erythroid bursts (BFU-E) from bone marrow mononuclear cells in a dose-dependent fashion. Over the concentration range tested (0.1-1000 microM), pretreatment with the aminothiols enhanced formation of CFU-GEMM up to five-fold and BFU-E nine-fold, compared to a three-fold increase in myeloid colony recovery. In CD34+ selected cells, preincubation with amifostine increased formation of CFU-GEMM up to 38-fold and produced macroscopic colonies, exceeding colony number in cultures initiated with optimal concentrations of interleukin-1 (IL-1), IL-3, or kit ligand (KL). When compared with recombinant human cytokines, amifostine enhanced IL-1 and IL-3 induced colony formation, although its stimulatory effect was less than additive. In contrast, pretreatment with amifostine antagonized the stimulatory effects of KL, whereas synergy was observed with concurrent exposure. Ex vivo expansion studies showed that amifostine alone supported and augmented the production of myeloid progenitors in secondary cultures. Similarly, under cytokine-deficient conditions, amifostine promoted cell survival and delayed apoptosis as measured by nucleosome generation. These data indicate that amifostine is a novel multipotent hematopoietic stimulant that augments the formation and survival of bone marrow progenitors.

Treatment with low-dose oral etoposide in patients with myelodysplastic syndromes

Forty-three patients with myelodysplastic syndromes (MDS) received treatment with oral etoposide 50 mg/day for 21 consecutive days every 4 weeks. Eighteen patients (42%) experienced hematological responses, including 12 of 17 (70%) patients with chronic myelomonocytic leukemia (CMML). Three of five CMML patients who failed treatment with hydroxyurea experienced major hematological responses with oral etoposide. Median response duration exceeded 9 months (range: 4-49 + months), and one patient remains in an unmaintained complete remission for 4 years. Toxicity included nausea/vomiting in five patients, fever (four patients), infection (three patients), mucositis (two patients), and anorexia (two patients). Two patients had grade 4 neutropenia with sepsis necessitating treatment withdrawal. We conclude that low-dose oral etoposide has remitting activity in MDS and is an effective treatment alternative for patients with CMML.

Stimulation of hematopoiesis by amifostine in patients with myelodysplastic syndrome

The aminothiol, amifostine (Ethyol; U.S. Bioscience, West Conshohocken, PA), is a cytoprotective agent that ameliorates the toxicities of anticancer therapy. In vitro, amifostine promotes the formation and survival of primitive hematopoietic progenitors derived from myelodysplastic bone marrow (BM) specimens. To evaluate the hematological effects of amifostine, 18 patients with myelodysplastic syndrome (MDS) and one or more refractory cytopenias received treatment with amifostine in a Phase I/II study. Four cohorts received intravenous treatment with 100, 200, or 400 mg/m2 amifostine three times a week, or 740 mg/m2 weekly for three consecutive weeks followed by 2 weeks observation. Nonresponding patients received a second course of therapy at the next higher dose level depending upon drug tolerance. Bone marrow (BM) progenitor growth was assessed before treatment and after day 21. Diagnoses included refractory anemia (7), refractory anemia with ringed sideroblasts (5), refractory anemia with excess blasts (RAEB) (4), and RAEB-in transformation (RAEB-t) (2). Single- or multi-lineage hematologic responses occurred in 15 patients (83%) treated with the three-times-a-week dose schedule. Fourteen patients had a 50% or greater increase in absolute neutrophil count with amifostine treatment (range, 426 to 11,348/microL). Platelet count increased in 6 (43%) of 14 patients with thrombocytopenia (absolute increase, 16, 000 to 110,000/microL), and 5 of 15 red blood cell transfusion-dependent patients had a 50% of greater reduction in transfusion needs. Assayable hematopoietic progenitors increased in 13 of 15 evaluable patients; including CFU-GEMM (12), BFU-E (8), and CFU-GM (6). Amifostine doses less than or equal to 200 mg/m2 were well tolerated, whereas grade II nausea, vomiting, and fatigue was limiting at higher doses. Three patients with excess blasts before enrollment experienced an increase in BM blast percentage and two patients had evolution to acute leukemia that persisted after treatment withdrawal. We conclude that amifostine administered at doses </=200 mg/m2 three times a week is well tolerated and has hematologic activity in patients with MDS.

Non-P-glycoprotein drug export mechanisms of multidrug resistance

A variety of cellular mechanisms of multidrug resistance (MDR) have been identified in human drug-resistant cell lines, and may play an important role in the clinical response of hematologic malignancies to chemotherapy. P-glycoprotein (P-gp)-mediated drug efflux is the most well-characterized cellular mechanism of MDR; however, several other non-P-gp membrane transporter proteins have also been implicated in the development of an MDR phenotype in hematologic malignancies. These include the MDR-related protein (MRP), the lung-resistance protein (LRP), and the transporter of antigenic peptides (TAP). The transporter proteins MRP and TAP are both members of the adenosine triphosphate (ATP)-binding cassette (ABC) family of transmembrane transporters, but each has distinct differences in substrate specificity. Despite effective modulation of P-gp, one or more of these alternate mechanisms of drug resistance may contribute to an MDR phenotype in tumor cell lines. Development of multifunctional MDR modulators or novel therapeutics may be necessary to effectively circumvent MDR in hematologic malignancies.

Amifostine protects normal tissues from paclitaxel toxicity while cytotoxicity against tumour cells is maintained

The objectives of this study were to evaluate the protective effects of amifostine against paclitaxel-induced toxicity to normal and malignant human tissues. Haematopoietic progenitor colony assays were used to establish the number of CFU-GEMM and BFU-E colonies after incubation with WR-1065 alone, Amifostine alone, paclitaxel (2.5 or 5 microM) +/- WR-1065 or amifostine. MTT and alkaline elution assays evaluated the in vitro growth inhibitory and DNA damaging effects, respectively, of paclitaxel with or without amifostine against normal human fibroblasts and human non-small cell lung cancer (NSCLC) cells. This combination was also evaluated in vivo using severe combined immune deficient (scid) mouse models of early (non-palpable tumours) and advanced (palpable tumours) human ovarian cancer. Human 2780 ovarian cancer cells were inoculated subcutaneously while paclitaxel and amifostine were administered intraperitoneally. A brief exposure (15 min) to amifostine not only protected human haematopoietic progenitor colonies from paclitaxel toxicity, but stimulated the growth of CFU-GEMM and BFU-E beyond control values. Amifostine protected normal human lung fibroblasts from paclitaxel-induced cytotoxicity and DNA single-strand breaks. However, paclitaxel cytotoxicity and DNA single-strand breaks were actually enhanced by pretreatment with amifostine in the NSCLC model. Importantly, amifostine did not interfere with paclitaxel antitumour activity even with prolonged exposure (24.5 h) of the lung cancer cells to high concentrations (1.2 mM) in vitro or following five repetitive high doses (200 mg/kg) given to scid mice with human ovarian cancer xenografts. Indeed, under certain circumstances, amifostine resulted in sensitisation of tumour cells to paclitaxel. Our results confirm previous reports of the ability of amifostine to protect normal tissues from the toxic effects of chemotherapy drugs and now extend these observations to paclitaxel.

Amifostine protects primitive hematopoietic progenitors against chemotherapy cytotoxicity

Controlled clinical trials indicate that amifostine (WR-2721, Ethyol) confers protection from the cumulative hematologic toxicities associated with alkylating agents and organoplatinums. To determine whether amifostine protects primitive hematopoietic progenitors from the cytotoxicity of functionally diverse antineoplastics, formation of the multipotent hematopoietic progenitors colony-forming units-granulocyte-erythroid, macrophage, megakaryocyte (CFU-GEMM) and erythroid burst-forming units (BFU-E) was evaluated using a clonogenic progenitor inhibition assay. Bone marrow mononuclear cells from normal donors were subjected to a 15-minute exposure of medium, amifostine (500 micromol/L), or WR-1065 (100 micromol/L at concentrations approximating peak plasma levels, washed twice, then treated with the antineoplastic for 1 to 6 hours. Colony growth was scored after 14 days of incubation. Amifostine conferred protection against a broader range of antineoplastics than did WR-1065. Amifostine protected CFU-GEMM against cytotoxicity from daunorubicin, mitoxantrone, and paclitaxel (range, 1.29- to 9.57-fold) (P < .05) but did not afford protection against cisplatin, diaziquone, or thiotepa. Similarly, amifostine protected BFU-E against toxicity from doxorubicin, mitoxantrone, paclitaxel, cisplatin, and diaziquone, yielding 3.4- to 65-fold greater colony recovery compared with controls. The high degree of cytoprotection afforded by amifostine derived largely from stimulation of progenitor growth at sublethal chemotherapy concentrations. In the absence of antineoplastic exposure, preincubation with amifostine or WR-1065 enhanced the colony-forming capacity of bone marrow progenitors from six normal donors, increasing recovery of CFU-GEMM and BFU-E up to sevenfold. We conclude that amifostine protects primitive hematopoietic progenitors from a wide range of antineoplastics. This broad hemoprotective effect derives in part from inherent trophic effects on progenitor growth and survival.

Role of multidrug resistance and its pharmacological modulation in acute myeloid leukemia

Cellular expression of the multidrug transporter, P-glycoprotein (Pgp) is recognized as a biological mechanism possibly contributing to treatment failure in acute myeloid leukemia (AML). Correlative studies indicate its association with poor risk features including secondary AML, CD34+ surface phenotype, unfavorable karyotype and advanced age. Reported disparity in the prognostic impact of Pgp relates in part to variance in drug transport capacity. In Pgp expressing cells, capacity for drug extrusion is governed by maturation phenotype and is largely restricted to CD34+ populations lacking myeloid maturation antigens. Three competitive inhibitors of Pgp function showing promise in pilot studies, cyclosporin A (CsA), quinine and the cyclosporin D analogue PSC 833, have entered testing in phase III trials. The presence of non-Pgp-related mechanisms of multidrug resistance, relatively insensitive to Pgp modulators, may limit the success of such treatment strategies. Preliminary investigations indicate that overexpression of the gene encoding the multidrug resistance-related protein (MRP) occurs infrequently in de novo AML, but relative increases in gene message are evident in relapsed specimens. Overexpression of lung resistance protein (LRP) is associated with adverse prognostic variables such as age, secondary disease and Pgp, and has demonstrated prognostic relevance. Because treatment with Pgp modulators may select for this drug resistance phenotype, LRP merits evaluation in randomized trials of Pgp antagonists. These observations indicate that multiple biological mechanisms contribute to anthracycline resistance in AML, thereby warranting development of multifunctional modulators or chemotherapeutic agents with novel mechanisms of action.

The role of multidrug resistance and its pharmacological modulation in acute myeloid leukemia

Despite more effective treatment for younger patients with acute myeloid leukemia (AML), resistance to conventional antineoplastics has limited such advances in the elderly. Overexpression of the multidrug transporter, P-glycoprotein (Pgp), appears to contribute to treatment failure in de novo AML and has been detected in up to 70 percent of elderly patients. Data also indicate linkage between Pgp and many adverse prognostic features, including cytogenetic pattern, surface phenotype, and evolution from an antecedent hematologic disorder. Pharmacologic inhibitors of Pgp function have been targeted for investigation in elderly AML patients. Non-Pgp mechanisms responsible for multidrug resistance (MDR) phenotypes that are only weakly sensitive to classic Pgp modulators, however, may limit the success of such strategies. Overexpression of the lung-resistance protein (LRP) in AML has also been linked to advanced age, secondary leukemia, and Pgp overexpression. In a study of 66 patients at the Arizona Cancer Center, LRP overexpression was a more important predictor of response to induction therapy for AML than was Pgp. Recent investigations indicate that overexpression of the gene encoding the MDR-related protein (MRP), though rare in de novo AML, may be common in high-risk groups such as relapsed patients and secondary AML. Use of monoclonal antibodies specific for the MRP gene product may further define its prognostic relevance in AML.

Overexpression of the major vault transporter protein lung-resistance protein predicts treatment outcome in acute myeloid leukemia

The monoclonal antibody LRP56 recognizes a 110-kD major vault protein (lung-resistance protein [LRP]) overexpressed in several P-glycoprotein-negative (Pgp-), multidrug resistant tumor cell lines. To determine the frequency of LRP overexpression, its prognostic significance, and its relation to Pgp, we analyzed bone marrow specimens from 87 consecutive patients with acute leukemia. Diagnoses included de novo acute myeloid leukemia (AML; 21 patients), leukemia arising from an antecedent hematologic disorder or prior cytotoxic therapy (secondary AML; 27 patients), AML in relapse (29 patients), and blast phase of chronic myeloid leukemia (CML-BP; 10 patients). A granular cytoplasmic staining pattern was detected by immunocytochemistry in 32 (37%) cases, including 7 (33%) de novo AML, 13 (48%) secondary AML, 11 (38%) relapsed AML, and 1 of 10 CML-BP. Among 66 evaluable patients with AML, LRP overexpression was associated with an inferior response to induction chemotherapy (P = .0017). Remissions were achieved in 35% of LRP+ patients as compared with 68% of LRP- patients. Although Pgp adversely affected response in univariate analysis (P = .0414), only LRP had independent prognostic significance when compared in a logistic regression model (P = .0046). Differences in remission duration (P = .075) and overall survival (P = .058) approached significance only for LRP. Sequential specimens from remitting patients receiving treatment with the Pgp modulator cyclosporin-A showed emergence of the LRP phenotype despite a decrease or loss of Pgp at the time of treatment failure (P =.0304). Significant associations were observed between LRP and age greater than 55 years (P = .017), Pgp (P = .040), and prior treatment with mitoxantrone (P = .020) but not with CD34. These findings indicate that overexpression of the novel transporter protein LRP is an important predictor of treatment outcome in AML.

Cytogenetics and P-glycoprotein (PGP) are independent predictors of treatment outcome in acute myeloid leukemia (AML)

Clinical and biological features have recognized prognostic significance in acute myeloid leukemia (AML). To evaluate the interaction of these variables and weighted effect on treatment outcome, prognostic variables from 96 previously untreated patients were analyzed for association with expression of the MDR1 gene product P-glycoprotein (Pgp), and effect on response to induction chemotherapy, progression-free survival and overall survival. Multivariate relationships were analyzed using six prognostic variables, including age, cytogenetic pattern, gender, CD34+ surface phenotype, AML type (de novo versus secondary) and Pgp. Univariate comparisons indicate that Pgp (P = 0.0001), cytogenetic pattern (P = 0.0004) and a Cd34+ phenotype (P = 0.0005) are predictive of primary treatment failure, whereas Pgp (P = 0.0001) had the greatest predictive value in multivariate analysis. Only cytogenetic pattern retained prognostic significance (P = 0.0143) for response to induction therapy after adjustment for Pgp. Although all variable except gender were associated with Pgp, specimens harboring the favorable karyotypic abnormalities t(15;17), t(8;21) and inv(16) exclusively lacked Pgp expression. In a multivariate model, both Pgp and cytogenetic pattern predicted response and overall survival, whereas secondary AML and cytogenetic pattern influenced remission duration. These findings indicate that cytogenetic has prognostic relevance that is independent of Pgp, and implies the presence of undefined biological mechanisms affecting chemotherapy resistance.

Low itraconazole serum concentrations following administration of itraconazole suspension to critically ill allogeneic bone marrow transplant recipients

OBJECTIVE

To report itraconazole serum concentrations following administration of itraconazole suspension via orogastric feeding tubes to 2 critically ill allogeneic bone marrow transplant recipients.

CASE SUMMARIES

A 38-year-old man and a 29-year-old man, each allogeneic bone marrow transplant recipients, were treated with oral itraconazole for documented fungal infections. Intubation and mechanical ventilation impeded ingestion of itraconazole capsules. Itraconazole was prepared initially as a suspension in intravenous lipid emulsion 20% and later as a suspension in citric acid 1.5% in D5W USP. Itraconazole serum concentrations were assayed using HPLC. Predose itraconazole serum concentrations were undetectable to 72 ng/mL. Postdose itraconazole serum concentrations were 5-97 ng/mL. Itraconazole concentrations measured in these patients were markedly lower than serum concentrations reported in the literature for similar doses administered to fed subjects.

DISCUSSION

Efficacy of this antifungal agent is limited currently by the patient's ability to ingest and absorb the itraconazole capsules. Pathophysiologic factors and suspension formulation issues that likely contributed to decreased itraconazole absorption are discussed.

CONCLUSIONS

Preparation and administration of itraconazole as a suspension did not enhance drug absorption in these patients. Furthermore, efficacy of itraconazole suspension may be affected by physical compatibility and chemical stability of the extemporaneous preparations.

Preclinical investigations of drug resistance

The effectiveness of antileukemic therapy is limited by intrinsic and acquired cellular resistance. Preclinical investigations support a complex and redundant network of cytoprotective mechanisms resulting from decreased drug accumulation, intracellular drug detoxification, alterations in nuclear targets of the antineoplastic agent, impaired transduction of growth arrest signals, and inherent cytokinetic resistance to S-phase active agents. Some, but not all, of these mechanisms are coordinately regulated, and correlative studies suggest that some may indeed contribute to clinical chemotherapy resistance.