Molecular alterations of the IDH1 gene in AML: a Children's Oncology Group and Southwest Oncology Group study

Recent whole-genome sequencing efforts led to the identification of IDH1^R132 mutations in AML patients. We studied the prevalence and clinical implications of IDH1 genomic alterations in pediatric and adult AML. Diagnostic DNA from 531 AML patients treated on Children’s Oncology Group trial COG-AAML03P1 (N=257), and Southwest Oncology Group trials SWOG-9031, SWOG-9333, and SWOG-9500 (N=274), were tested for IDH1 mutations. Codon R132 mutations were absent in the pediatric cohort, but were found in 12/274 adult patients (4.4%, 95% CI 2.3-7.5%). IDH1^R132 mutations occurred most commonly in patients with normal karyotype, and those with FLT3/ITD and NPMc mutations. Patients with IDH1^R132 mutations trended towards higher median diagnostic WBC counts (59.2 × 10⁹/L vs. 29.1 × 10⁹/L, P=0.19) than those without mutations, but the two groups did not differ significantly in age, bone marrow blast percentage, overall survival, or relapse-free survival. Eleven patients (2.1%) harbored a novel V71I sequence alteration, which was found to be a germline polymorphism. IDH1 mutations were not detected in pediatric AML, and are uncommon in adult AML.

Childhood leukaemia in Belarus, Russia, and Ukraine following the Chernobyl power station accident: results from an international collaborative population-based case–control study

BACKGROUND

There is little evidence regarding the risk of leukaemia in children following exposure to radionuclides from the Chernobyl Nuclear Power Plant explosion on April 26, 1986.

METHODS

This population-based case-control study investigated whether acute leukaemia is increased among children who were in utero or <6 years of age at the time of the Chernobyl accident. Confirmed cases of leukaemia diagnosed from April 26, 1986 through December 31, 2000 in contaminated regions of Belarus, Russia, and Ukraine were included. Two controls were matched to each case on sex, birth year, and residence. Accumulated absorbed radiation dose to the bone marrow was estimated for each subject.

RESULTS

Median estimated radiation doses of participants were <10 mGy. A significant increase in leukaemia risk with increasing radiation dose to the bone marrow was found. This association was most evident in Ukraine, apparent (but not statistically significant) in Belarus, and not found in Russia.

CONCLUSION

Taken at face value, these findings suggest that prolonged exposure to very low radiation doses may increase leukaemia risk as much as or even more than acute exposure. However the large and statistically significant dose-response might be accounted for, at least in part, by an overestimate of risk in Ukraine. Therefore, we conclude this study provides no convincing evidence of an increased risk of childhood leukaemia as a result of exposure to Chernobyl radiation, since it is unclear whether the results are due to a true radiation-related excess, a sampling-derived bias in Ukraine, or some combination thereof. However, the lack of significant dose-responses in Belarus and Russia also cannot convincingly rule out the possibility of an increase in leukaemia risk at low dose levels.

Iodine deficiency, radiation dose, and the risk of thyroid cancer among children and adolescents in the Bryansk region of Russia following the Chernobyl power station accident

BACKGROUND

Little is known about the joint effect of iodine deficiency and radiation exposure on the risk of thyroid cancer. No epidemiological studies have been published assessing the modifying effect of iodine deficiency on radiation-induced thyroid cancer following the Chernobyl accident.

METHODS

A population sample of 3070 individuals (2590 ages 6-18, and 480 adults) from 75 settlements in the most highly contaminated regions of the Bryansk Oblast of Russia was identified and sampled for urinary iodine measurements in 1996, and iodine deficiency in each geopolitical unit (raion) was estimated. All cases of thyroid cancer were identified in those born 1968-1986 who were resident in the study area in May-June 1986 (34 histologically confirmed cases). The risk of thyroid cancer was examined in relation to population estimates of thyroid radiation dose and urinary iodine excretion level.

RESULTS

The excess relative risk (ERR) of thyroid cancer was significantly associated with increasing thyroid radiation dose, and was inversely associated with urinary iodine excretion levels. There was a joint effect of radiation exposure and iodine deficiency. At 1 gray (Gy), the ERR in territories with severe iodine deficiency was approximately two times that in areas of normal iodine intake.

CONCLUSIONS

These findings suggest that elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid. If confirmed by studies based on individuals, they may have implications for the use of stable iodine in the case of population exposure to radioactive iodine.

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.

FLT3, RAS, and TP53 mutations in elderly patients with acute myeloid leukemia

The prevalence and significance of genetic abnormalities in older patients with acute myeloid leukemia (AML) are unknown. Polymerase chain reactions and single-stranded conformational polymorphism analyses were used to examine 140 elderly AML patients enrolled in the Southwest Oncology Group study 9031 for FLT3, RAS, and TP53 mutations, which were found in 34%, 19%, and 9% of patients, respectively. All but one of the FLT3 (46 of 47) mutations were internal tandem duplications (ITDs) within exons 11 and 12. In the remaining case, a novel internal tandem triplication was found in exon 11. FLT3 ITDs were associated with higher white blood cell counts, higher peripheral blast percentages, normal cytogenetics, and less disease resistance. All RAS mutations (28 of 28) were missense point mutations in codons 12, 13, or 61. RASmutations were associated with lower peripheral blast and bone marrow blast percentages. Only 2 of 47 patients with FLT3 ITDs also had a RAS mutation, indicating a significant negative association between FLT3 and RAS mutations (P = .0013). Most TP53 mutations (11 of 12) were missense point mutations in exons 5 to 8 and were associated with abnormal cytogenetics, especially abnormalities in both chromosomes 5 and 7. FLT3 and RAS mutations were not associated with inferior clinical outcomes, but TP53mutations were associated with a worse overall survival (median 1 versus 8 months, P = .0007). These results indicate that mutations in FLT3, RAS, or TP53 are common in older patients with AML and are associated with specific AML phenotypes as defined by laboratory values, cytogenetics, and clinical outcomes.

Methylation profiling in acute myeloid leukemia

Aberrant methylation of multiple CpG islands has been described in acute myeloid leukemia (AML), but it is not known whether these are independent events or whether they reflect specific methylation defects in a subset of cases. To study this issue, the methylation status of 14 promoter-associated CpG islands was analyzed in 36 cases of AML previously characterized for estrogen-receptor methylation (ERM). Cases with methylation density of 10% or greater were considered positive. Seventeen cases (47%) were ERM(+) while 19 cases were ERM(-). Hypermethylation of any of the following, p15, p16, CACNA1G, MINT1, MINT2, MDR1, THBS1, and PTC1 (2 promoters), was relatively infrequent (6% to 31% of patients). For each of these CpG islands, the methylation density was positively correlated with ERM density (rank order correlation coefficients, 0.32-0.59; 2-tailed P < or = .058 for each gene). Hypermethylation of MYOD1, PITX2, GPR37, and SDC4 was frequently found in AML (47% to 64% of patients). For each of these genes as well, methylation density was positively correlated with ERM density (correlation coefficients 0.43 to 0.69, P < or = .0087 for each gene). MLH1 was unmethylated in all cases. Hypermethylation of p15, MDR1, and SDC4 correlated with reduced levels of expression. There was an inverse correlation between age and the number of genes methylated (P = .0030). It was concluded that CpG-island methylation in AML results from methylation defects in subsets of cases. These results have potential implications for the classification and prognosis of AML and for the identification of patients who may benefit from treatment with methylation inhibitors.

Comparison of the L10M consolidation regimen to an alternative regimen including escalating methotrexate/L-asparaginase for adult acute lymphoblastic leukemia: a Southwest Oncology Group Study

The effectiveness of intensive post-remission chemotherapy regimens for adult patients with acute lymphoblastic leukemia (ALL) is limited by both a high rate of disease recurrence and a substantial incidence of treatment toxicity. To evaluate a potentially more effective and less toxic approach, we conducted a multicenter phase III trial of consolidation therapies comparing the standard L10M regimen with one combining the brief, intensive L17M regimen and escalating methotrexate (MTX) and L-asparaginase (L-asp). Patients over age 15 with previously untreated ALL were eligible. Induction therapy included vincristine, prednisone, doxorubicin, cyclophosphamide and intrathecal methotrexate administered over 36 days. Patients who achieved complete remission (CR) were randomized to receive consolidation with either the L10M regimen or with DAT (daunomycin, cytosine arabinoside, 6-thioguanine) and escalating MTX and L-asp. The randomization was stratified by age, WBC and Ph chromosome status. Maintenance therapy was the same in both arms. Of 353 eligible patients, 218 (62%) achieved CR and 195 were randomized. The treatment arms did not differ significantly with respect to disease-free survival (DFS; P= 0.46) or overall survival (P= 0.39). Estimated DFS at 5 years was 32% (95% confidence interval (CI) 23-42%) in the L10M arm and 25% (95% CI 16-33%) in the DAT/MTX/L-asp arm. In each arm, 4% of patients died of toxicities (infection in all but one case). Infections and nausea/vomiting were somewhat more common in the L10M arm (occurring in 68% and 53% of patients respectively) than the DAT/MTX/L-asp arm (56% and 33%). The DAT/MTX/L-asp consolidation regimen was associated with some reduction in nonfatal toxicities, but no significant improvement in DFS, overall survival or non-relapse mortality when compared to the standard L10M regimen.

Karyotypic analysis predicts outcome of preremission and postremission therapy in adult acute myeloid leukemia: a Southwest Oncology Group/Eastern Cooperative Oncology Group Study

The associations of cytogenetics with complete remission (CR) rates, overall survival (OS), and outcomes after CR were studied in 609 previously untreated AML patients younger than 56 years old in a clinical trial comparing 3 intensive postremission therapies: intensive chemotherapy, autologous transplantation (ABMT), or allogeneic bone marrow transplantation (alloBMT) from matched related donors. Patients were categorized into favorable, intermediate, unfavorable, and unknown cytogenetic risk groups based on pretreatment karyotypes. CR rates varied significantly (P <.0001) among the 4 groups: favorable, 84% (95% confidence interval [CI], 77%-90%); intermediate, 76% (CI, 71%-81%); unfavorable, 55% (CI, 48%-63%); and unknown, 54% (CI, 33%-74%). There was similar significant heterogeneity of OS (P <.0001), with the estimated relative risk of death from any cause being 1.50 (CI, 1.10-2.05), 3. 33 (CI, 2.43-4.55), and 2.66 (CI, 1.59-4.45) for the intermediate, unfavorable, and unknown risk groups, respectively, compared with the favorable group. In multivariate analyses, the effects of cytogenetic risk status on CR rate and OS could not be explained by other patient or disease characteristics. Among postremission patients, survival from CR varied significantly among favorable, intermediate, and unfavorable groups (P =.0003), with significant evidence of interaction (P =.017) between the effects of treatment and cytogenetic risk status on survival. Patients with favorable cytogenetics did significantly better following ABMT and alloBMT than with chemotherapy alone, whereas patients with unfavorable cytogenetics did better with alloBMT. Cytogenetic risk status is a significant factor in predicting response of AML patients to therapy; however, to tighten treatment correlates within genetically defined AML subsets, a significantly larger leukemia cytogenetic database is warranted.

Long-term follow-up of remission duration, mortality, and second malignancies in hairy cell leukemia patients treated with pentostatin

The nucleoside analogue, pentostatin, has demonstrated high complete response rates and long relapse-free survival times in patients with hairy cell leukemia, a disease that historically had been unresponsive to treatment. Long-term data on duration of overall survival and relapse-free survival and incidence of subsequent malignancies with this agent are lacking. Patients completing the treatment phase of a randomized, intergroup study who received pentostatin as an initial treatment or who crossed over after failure of interferon alpha were followed for survival, relapse, and diagnosis of subsequent malignancies. Two hundred forty-one patients treated with pentostatin as initial therapy (n = 154) or who crossed over after failure of interferon alpha (n = 87) were followed for a median duration of 9.3 years. Estimated 5- and 10-year survival rates (95% confidence interval) for all patients combined were 90% (87%-94%) and 81% (75%-86%), respectively. In the 173 patients with a confirmed complete response to pentostatin treatment, 5- and 10-year relapse-free survival rates were 85% (80%-91%) and 67% (58%-76%), respectively. Survival curves for patients initially treated with pentostatin and those crossed over were similar. Only 2 of 40 deaths were attributed to hairy cell leukemia. The mortality rate and incidence of subsequent malignancies were not higher than expected in the general population. Pentostatin is a highly effective regimen for hairy cell leukemia that produces durable complete responses. Subsequent malignancies do not appear to be increased with pentostatin treatment.

A phase I study of induction chemotherapy for older patients with newly diagnosed acute myeloid leukemia (AML) using mitoxantrone, etoposide, and the MDR modulator PSC 833: a southwest oncology group study 9617

Older patients with acute myelogenous leukemia (AML) have overexpression of P-glycoprotein (Pgp+), and this has been shown to correlate quantitatively with therapeutic outcome. Since Pgp-mediated efflux of cytotoxic drugs can be inhibited by the cyclosporine analogue, PSC 833, we investigated the use of this agent with a 5-day mitoxantrone/etoposide regimen in patients over age 55 with newly diagnosed AML. Previous studies suggested a 33% incidence of grade IV/V non-hematologic toxicity with the use of mitoxantrone 10 mg/M(2) and etoposide 100 mg/M(2), each for 5 days, in this patient population. Since PSC 833 alters the pharmacokinetic excretion of MDR-related cytotoxins, this phase I dose-finding study was performed to identify doses of mitoxantrone/etoposide associated with a similar 33% incidence of grade IV/V non-hematologic toxicity, when given with PSC 833. Mitoxantrone/etoposide (M/E) doses were escalated in fixed ratio from a starting dose of M: 4 mg/M(2) and E: 40 mg/M(2), to M: 7 mg/M(2) and E: 70 mg/M(2), in successive cohorts of eight patients each. PSC 833 was well tolerated and the MTD of this M/E regimen with PSC 833 in this population was M: 6 mg/M(2) and E: 60 mg/M(2). The complete response (CR) rate for all patients was 50% (15/30) and was considerably higher for de novo than for secondary AML. These data suggest that the addition of PSC 833 to an M/E regimen for older patients with untreated AML is well tolerated but requires a reduction in M/E dosing to avoid increased toxicity.

Twenty-four-color spectral karyotyping reveals chromosome aberrations in cytogenetically normal acute myeloid leukemia

Multicolor spectral karyotyping allows simultaneous visualization of all human chromosomes and screening for chromosomal rearrangements without a priori knowledge of any abnormalities involved. Based on this potentially increased sensitivity, we investigated, in a preliminary manner, whether spectral karyotyping could detect cytogenetic aberrations in karyotypically normal leukemia. The test population was comprised of 28 cryopreserved, cytogenetically normal acute myeloid leukemia (AML) samples from patients registered to a randomized trial for previously untreated AML (SWOG 9031). Two normal and 12 samples with known cytogenetic aberrations were used to validate and establish the diagnostic accuracy of the spectral karyotyping assay and instrumentation in a clinical setting. Enumeration and region-specific DNA fluorescence in situ hybridization (FISH) probes verified discrepant results. In the validation data set, spectral karyotyping refined complex karyotypic rearrangements in six cases and defined the chromosomal origin of a "jumping" homogeneously staining region; however, the technology was less sensitive in the detection of subtelomeric rearrangements and double minute chromosomes. In the test population, spectral karyotyping identified previously undetected cytogenetic aberrations in two cases (7%) of karyotypically normal AML: a cryptic 11q23 translocation in 20/20 cells and a minor monosomy 7 clone in 3/21 cells (FISH, 10.5%). Both of these abnormalities are considered to confer a poor prognosis when based on classical cytogenetic prognostic criteria. As an adjunct to classical cytogenetics and standard FISH analyses, the additive resolution of spectral karyotyping, in particular, with chromosome paints spiked with subtelomeric and/or locus-specific probes, may allow significant gains to be made in diagnostic accuracy and recognition of genotype/phenotype prognostic relationships, and in defining underlying biologic mechanisms in cancer. Genes Chromosomes Cancer 28:318-328, 2000.

Microsatellite instability is not a defining genetic feature of acute myeloid leukemogenesis in adults: results of a retrospective study of 132 patients and review of the literature

The frequency of acute leukemia in children with constitutional DNA repair defects implicates defective DNA repair in leukemogenesis. Whether sporadic cases of AML also arise from an inherited genetic predisposition remains to be determined. Prior studies have reported microsatellite instability (MSI) in AML, particularly secondary and relapsed AML. These studies included small numbers of cases in which key features such as cytogenetic abnormalities were not reported. To determine whether defective DNA mismatch repair, reflected by MSI, is a defining feature of adult myeloid leukemogenesis, we retrospectively studied 132 AML cases including 28 de novo, 62 secondary, 22 relapsed/refractory, 15 cases of paired diagnosis/relapse. 110 patients were elderly (55+ years). The cases included a range of cytogenetic abnormalities. MSI was assessed at three loci (BAT 25, BAT 26, BAT 40) in DNA isolated from sorted leukemic blasts and paired T cell controls. Fluoresceinated PCR products were analyzed using an automated capillary electrophoresis system. Of the 132 AML cases, no single case demonstrated MSI. Our studies indicate that MSI, and defective DNA mismatch repair, is not a defining feature of the majority of adult patients with AML. Furthermore, our data does not support the hypothesis that MSI could be acquired during the progression of AML from diagnosis to relapse, as a consequence of therapeutic exposure.

Glutathione S-transferase theta 1 gene deletion and risk of acute myeloid leukemia

Individuals with a homozygous deletion of the glutathione S-transferase theta 1 (GSTT1) gene lack GSTT1 enzymatic detoxification of environmental carcinogens by conjugation with glutathione. The GSTT1 gene deletion has been associated with carcinogen-induced chromosomal changes in lymphocytes, and some but not all epidemiological evidence has suggested that the GSTT1 gene deletion may increase susceptibility to myelodysplasia. We conducted a case-control study to test whether individuals with an inherited homozygous deletion of the GSTT1 gene are at increased risk of acute myeloid leukemia (AML). The GSTT1 and GST mu 1 (GSTM1) genotypes were determined by PCR using lymphocyte or bone marrow DNA from 297 AML patients and 152 controls. AML patients were selected from Southwest Oncology Group clinical studies, and controls were identified by random digit dialing in Washington state. No association was observed between the GSTT1 gene deletion and AML [race-adjusted odds ratio (OR), 0.94; 95% confidence interval (CI), 0.55-1.60] or between the GSTM1 gene deletion and AML (race-adjusted OR, 1.26; 95% CI, 0.85-1.88). Patients with secondary AML had a slightly higher prevalence of the GSTT1 and GSTM1 gene deletions compared with de novo AML patients or controls, but this was consistent with chance. Exploratory analyses of AML cytogenetics suggested a few associations, i.e., between the GSTT1 gene deletion and trisomy 8, and between the GSTM1 gene deletion and non-8 trisomies or inv(16). These results do not support the hypothesis that the GSTT1 gene deletion is related to the incidence of AML.

A phase III comparison of high dose ARA-C (HIDAC) versus HIDAC plus mitoxantrone in the treatment of first relapsed or refractory acute myeloid leukemia Southwest Oncology Group Study

The aim of this study is to determine whether the addition of mitoxantrone to high dose cytarabine improves the outcome of treatment in patients with relapsed or refractory acute myeloid leukemia (AML). One hundred and sixty-two eligible patients, 14-76 years of age, with AML either in first relapse or that failed to respond to initial remission induction therapy, with no CNS involvement were randomized to receive therapy with cytarabine 3 gm/M2 i.v. over 2 h every 12 h for 12 doses on days 1-6 (Arm I) (HIDAC); or HIDAC plus mitoxantrone 10 mg/M2 i.v. daily on days 7 9 (Arm II) (HIDAC + M). Patients achieving complete remission were treated with three courses of consolidation including HIDAC (Ara-C 3 gm/M2 i.v. 12 h days 1 3; 2 gm/M2 over age 50) alone (ARM I) or with mitoxantrone (10 mg/M2 i.v. day 1) (ARM II). Among 162 patients (81 HIDAC, 81 HIDAC + M) evaluated for induction toxicity, there were 10 (12%) induction deaths with HIDAC and 13 (17%) with HIDAC + M (2-tailed P = 0.65). Most early deaths were due to infection and/or hemorrhage. Among 162 patients evaluated for responses to induction therapy, 26/81 (32%) HIDAC and 36/81 (44%) HIDAC + M patients achieved complete remission (two-tailed P = 0.15). Although this difference was not statistically significant in univariate analysis, it was after adjusting for the effects of WBC and PMN percentage in multivariate analysis (P=0.013). Median survivals from study entry were 8 months (HIDAC) and 6 months (HIDAC + M); 2-tailed logrank P = 0.58. Among 48 patients registered for consolidation, the median disease-free survivals from that registration were 8 months with HIDAC and 11 months with HIDAC + M (P = 0.60). There were three treatment-related deaths during consolidation (1 HIDAC, 2 HIDAC + M), all due to infections. In this randomized trial, the addition of mitoxantrone to high-dose cytarabine was associated with a trend toward a higher CR rate. There was less evidence for an advantage in disease-free or overall survival, although any such conclusion is limited by the size of the study.

Frequency and clinical significance of the expression of the multidrug resistance proteins MDR1/P-glycoprotein, MRP1, and LRP in acute myeloid leukemia: a Southwest Oncology Group Study

Therapeutic resistance is a major obstacle in the treatment of acute myeloid leukemia (AML). Such resistance has been associated with rapid drug efflux mediated by the multidrug resistance gene 1 (MDR1; encoding P-glycoprotein) and more recently with expression of other novel proteins conferring multidrug resistance such as MRP1 (multidrug resistance-associated protein 1) and LRP (lung resistance protein). To determine the frequency and clinical significance of MDR1, MRP1, and LRP in younger AML patients, we developed multiparameter flow cytometric assays to quantify expression of these proteins in pretreatment leukemic blasts from 352 newly diagnosed AML patients (median age, 44 years) registered to a single clinical trial (SWOG 8600). Protein expression was further correlated with functional efflux by leukemic blasts [assessed using two substrates: Di(OC)(2) and Rhodamine 123] and with the ability of MDR-reversing agents to inhibit efflux in vitro. MDR1/P-glycoprotein expression, which was highly correlated with cyclosporine-inhibited efflux, was noted in only 35% of these younger AML patients, distinctly lower than the frequency of 71% we previously reported in AML in the elderly (Blood 89:3323, 1997). Interestingly, MDR1 expression and functional drug efflux increased with patient age, from a frequency of only 17% in patients less than 35 years old to 39% in patients aged 50 years (P =.010). In contrast, MRP1 was expressed in only 10% of cases and decreased with patient age (P =. 024). LRP was detected in 43% of cases and increased significantly with increasing white blood cell counts (P =.0015). LRP was also marginally associated with favorable cytogenetics (P =.012) and French-American-British (FAB) AML FAB subtypes (P =.013), being particularly frequent in M4/M5 cases. Only MDR1/P-glycoprotein expression and cyclosporine-inhibited efflux were significantly associated with complete remission (CR) rate (P(MDR1) =.012; P(efflux) =.039) and resistant disease (RD; P(MDR1) =.0007; P(efflux) =.0092). No such correlations were observed for MRP1 (P(CR) =.93; P(RD) =.55) or LRP (P(CR) =.50; P(RD) =.53). None of these parameters were associated with overall or relapse-free survival. Unexpectedly, a distinct and nonoverlapping phenotype was detected in 18% of these cases: cyclosporine-resistant efflux not associated with MDR1, MRP1, or LRP expression, implying the existence of other as yet undefined efflux mechanisms in AML. In summary, MDR1 is less frequent in younger AML patients, which may in part explain their better response to therapy. Neither MRP1 nor LRP are significant predictors of outcome in this patient group. Thus, inclusion of MDR1-modulators alone may benefit younger AML patients with MDR1(+) disease.

Minimal residual disease in patients with hairy cell leukemia in complete remission treated with 2-chlorodeoxyadenosine or 2-deoxycoformycin and prediction of early relapse

The purine nucleoside analogues 2-chlorodeoxyadenosine (2-CdA) and 2'-deoxycoformycin (2'-DCF) induce complete remission (CR) in the majority of patients with hairy cell leukemia. However, minimal residual disease (MRD) has been detected in bone marrow core biopsies using immunohistochemical techniques in patients achieving CR by conventional criteria. This study was designed to compare the prevalence of MRD with each agent in patients in CR by using conventional criteria and the relapse-free survival for patients with and without MRD. Bone marrow biopsies from 39 patients treated with a single cycle of 2-CdA and 27 patients treated with multiple cycles of 2'-DCF were studied. The monoclonal antibodies anti-CD20, DBA.44, and anti-CD45RO were used to evaluate the paraffin-embedded bone marrow core biopsies for MRD. Five of 39 patients (13%) treated with 2-CdA had MRD, as compared to 7 of 27 patients (26%) treated with 2'-DCF (two-tailed P = 0.21). Relapse has occurred in two of the five patients with MRD after 2-CdA treatment and in four of the seven patients with MRD after 2'-DCF treatment. In total, 6 of the 12 patients (50%) with MRD have relapsed, whereas 3 of 54 patients (6%) without MRD have relapsed, and 2 patients have died without evidence of relapse. The estimated 4-year relapse-free survival among patients with MRD is 55% (+/- 15%, SE), compared to 88% (+/- 5%, SE) among patients without MRD (two-tailed P = 0.0023). The prevalence of MRD detected in a subset of patients in CR after either 2-CdA or 2'-DCF treatment did not differ significantly. However, the presence of MRD is associated with an increased risk of relapse.

Estrogen receptor methylation is associated with improved survival in adult acute myeloid leukemia

Estrogen receptor methylation (ERM) is a frequent molecular alteration in adult acute myeloid leukemia (AML). In this study, we sought to determine the clinical characteristics and prognostic significance of ERM in AML. ERM was determined for 268 patients who had leukemic blasts available for molecular analysis. ERM was measured by Southern blot analysis, and results were obtained for 261 patients (ages 17-69). ERM ranged from 0-99.1%, with a median of 25%. One hundred sixty patients (61%) had ERM values over 15% and were considered ERM+. In a subset of patients analyzed, ERM+ samples had markedly lower ER gene expression compared with ERM- samples. In multiple regression analyses of patient and disease characteristics at diagnosis, two factors had significant independent association with ERM: ERM decreased with increasing age (P = 0.0001) and was significantly lower in patients with French-American-British classification M4 or M5 (P = 0.0019). In regression analyses of outcome measures, ERM had no significant impact on complete remission rate after initial induction therapy. However, ERM+ patients had significantly better overall survival [OS; 18% at 6 years; 95% confidence interval (CI), 12-24% versus 9%; CI, 3-14% for ERM- patients; P = 0.022]. In multiple regression analyses, OS increased with increasing ERM (P = 0.0044). Similar results were seen for relapse-free survival (23% at 6 years; CI, 15-32% for ERM+ versus 10%; CI, 2-19% for ERM-), although the effect of ERM was not statistically significant (P = 0.15 in multiple regression analysis). Our results indicate that ERM at diagnosis may be a favorable prognostic factor for OS in adult AML.

Malignant progenitors from patients with acute myelogenous leukemia are sensitive to a diphtheria toxin-granulocyte-macrophage colony-stimulating factor fusion protein

We have previously demonstrated that human granulocyte-macrophage colony-stimulating factor (GM-CSF) fused to a truncated diphtheria toxin (DT388-GMCSF) kills acute myelogenous leukemia (AML) cell lines bearing the GM-CSF receptor. We now report that exposure of malignant cells from 50 different patients with AML for 48 hours in culture to DT388-GMCSF reduces by a median of 1.6 logs (range, 0 to 3.7 logs) the number of leukemic cells capable of forming colonies in semisolid media (leukemic colony-forming cells [CFU-L]) with a median IC50 of 3 x 10(-12) mol/L (range, 5 to >4,000 x 10(-12) mol/L). Furthermore, the cell kill is dependent on the presence of high-affinity GM-CSF receptors on leukemic blasts, because CFU-L from 27 of 28 AML samples expressing > or = 35 GM-CSF receptors per cell were inhibited by the toxin, whereas the colony growth from all 4 leukemic samples (2 AML, 1 acute lymphoblastic leukemia [ALL], and 1 prolymphocytic leukemia [PLL]) that had less than 35 receptors per cell was unaffected by the drug. Sensitivity of CFU-L to DT388-GMCSF was seen regardless of the clinical responsiveness of the patient's leukemia to standard chemotherapy agents. In contrast, clonogenic cells from normal bone marrow formed colonies at near control numbers after exposure to much higher toxin concentrations (4 x 10(-9) mol/L) than those required to kill CFU-L from most patients. Thus, leukemic progenitors isolated directly from the peripheral blood of most AML patients show the same sensitivity to DT388-GMCSF as previously demonstrated for AML cell lines. Under the same conditions of exposure, normal hematopoietic progenitors are relatively unaffected by DT388-GMCSF, suggesting its potential as a therapeutic agent in AML.

A double-blind placebo-controlled trial of granulocyte colony-stimulating factor in elderly patients with previously untreated acute myeloid leukemia: a Southwest oncology group study (9031)

Older age is a poor prognosis factor in acute myeloid leukemia (AML). This double-blind trial was designed to test the hypothesis that granulocyte colony-stimulating factor (G-CSF) used as supportive care could improve the treatment of elderly AML patients. Two hundred thirty-four patients 55 or more years of age with a morphologic diagnosis of de novo or secondary AML, French-American-British (FAB) M0-M7, excluding M3, were randomly assigned to a standard induction regimen (daunorubicin at 45 mg/m2 intravenously [IV] on days 1 through 3 and Ara-C at 200 mg/m2 IV continuous infusion on days 1 through 7) plus either placebo or G-CSF (400 microg/m2 IV over 30 minutes once daily). Results are reported here for 211 centrally confirmed cases of non-M3 AML. The two groups were well balanced in demographic, clinical, and hematological parameters, with median ages of 68 years in the G-CSF and 67 years in the placebo groups. The complete response (CR) rate was not significantly better in the G-CSF group: 50% in the placebo and 41% in the G-CSF group (one-tailed P = .89). Median overall survival was also similar, 9 months (95% confidence interval [CI], 7 to 10 months) in the placebo and 6 months (95% CI, 3 to 8 months) in the G-CSF arms (P = .71). We found a significant 15% reduction in the time to neutrophil recovery in the G-CSF group (P = .014). G-CSF had no impact on recovery from thrombocytopenia (P = .80) or duration of first hospitalization (P = .27). When infection complications were evaluated, G-CSF had a beneficial effect on the duration but not on incidence of infection. G-CSF patients had fewer days with fever and shorter duration of antibiotic use. However, there was no difference in the frequency of total documented infections or in the number of fatal infections (19% placebo v 20% G-CSF). In this study of elderly AML patients, G-CSF improved clinical parameters of duration of neutropenia and antibiotic use, but did not change CR rate or survival or shorten hospitalization.

Long-term survival after chemotherapy for acute myeloid leukemia: the experience of the Southwest Oncology Group

BACKGROUND

Reports on outcomes of chemotherapy trials in acute myeloid leukemia (AML) have rarely included results of long-term follow-up beyond 10 years. The authors therefore chose to review long-term follow-up data from 3 studies conducted by the Southwest Oncology Group (SWOG) between 1978 and 1990.

METHODS

The analysis included data on 2083 patients enrolled in SWOG studies S7823, S8124, and S8600. The results were based on data available as of November 15, 1996.

RESULTS

The probability of survival 8 years after entry was 9% in Study S7823, 14% in S8124, and 15% in S8600. For patients age < 50 years, the probabilities were 14%, 24%, and 20%, respectively. For patients ages 50-64 years, the probabilities were 7%, 8%, and 8%, respectively. For those age < 50 years who achieved complete remission, the 8-year probability of disease free survival was 17% in Study S7823, 28% in S8124, 17% with standard dose cytarabine in S8600, and 26% with high dose cytarabine in S8600. Relapse was the major reason for failure after complete remission in all three studies. When the results of the 3 studies were combined, most of the 743 relapses had occurred by Year 3 and nearly all the rest by Year 5. Among the prognostic factors universally available for study, three were highly associated with survival in all three studies: age, French-American-British disease classification, and white blood cell count at diagnosis.

CONCLUSIONS

In view of the fact that most deaths occurred during the first 3 years, it is appropriate to report the results of clinical trials after patients have been followed for 4 years. Despite modest gains, the results of chemotherapy for AML remain disappointing, especially in the treatment of older patients.

Acute myeloid leukemia in the elderly: assessment of multidrug resistance (MDR1) and cytogenetics distinguishes biologic subgroups with remarkably distinct responses to standard chemotherapy. A Southwest Oncology Group study

Compared with younger patients, elderly patients with acute myeloid leukemia (AML) respond poorly to conventional chemotherapy. To determine if this poor response is due to differences in the biologic characteristics of AML in the elderly, we studied 211 patients (161 de novo, 50 secondary AML) over 55 years of age (median, 68 years) registered to a single clinical trial for previously untreated AML (SWOG 9031, Phase III randomized trial of standard dose cytosine arabinoside and daunomycin + rhG-CSF). Pretreatment leukemic blasts were karyotyped and were also analyzed for intrinsic drug resistance by quantitating expression of the multidrug resistance glycoprotein MDR1 and functional drug efflux using sensitive flow cytometric techniques. Results were correlated with clinical variables and outcome. These elderly AML patients had a high frequency of unfavorable cytogenetics (32%), MDR1 protein expression (71%), and functional drug efflux (58%); each of these factors occurred at high frequencies in both de novo and secondary AML patients and was associated with a significantly poorer complete remission (CR) rate. In multivariate analysis, secondary AML (P = .0035), unfavorable cytogenetics (P = .0031), and MDR1 (P = .0041) were each significantly and independently associated with lower CR rates. Resistant disease was associated with unfavorable cytogenetics (P = .017) and MDR1 expression (P = .0007). Strikingly, elderly MDR1(-) de novo AML patients with favorable/intermediate cytogenetics had a CR rate of 81%; with increasing MDR1 expression, CR rate decreased in this cytogenetic group. MDR1(+) secondary AML patients with unfavorable cytogenetics had a CR rate of only 12%. Thus, AML in the elderly is associated with an increased frequency of unfavorable cytogenetics and MDR1 expression, both of which independently contribute to poor outcomes. The high frequencies of these features in both de novo and secondary elderly AML patients suggest a common biologic mechanism for these leukemias distinct from that in younger patients. Investigation of biologic parameters at diagnosis in AML in the elderly may help identify patients with a high likelihood of achieving CR with conventional regimens, as well as those who may require alternate regimens designed to overcome therapy resistance.

A randomized investigation of high-dose versus standard-dose cytosine arabinoside with daunorubicin in patients with previously untreated acute myeloid leukemia: a Southwest Oncology Group study

Interest in high-dose cytarabine (HDAC) for both induction and postremission therapy for acute myeloid leukemia (AML) prompted the Southwest Oncology Group (SWOG) to initiate a randomized trial comparing HDAC with standard-dose cytarabine (SDAC) for remission induction of previously untreated AML and to compare high-dose treatment versus conventional doses for consolidation therapy. Patients less than 65 years of age with de novo or secondary AML were randomized for induction between SDAC 200 mg/ m2/d for 7 days by continuous infusion or HDAC at 2 g/ m2 intravenously every 12 hours for 12 doses; both groups received daunorubicin (DNR) at 45 mg/m2/d intravenously for 3 days. Complete responders to SDAC were randomized to receive either two additional courses of SDAC plus DNR or one course of HDAC plus DNR. Complete responders to HDAC were nonrandomly assigned to receive one additional course of HDAC plus DNR. Of patients randomized between SDAC (n = 493) and HDAC (n = 172) induction, 361 achieved complete remission (CR). The CR rate was slightly poorer with HDAC: 55% versus 58% with SDAC for patients aged less than 50, and 45% (HDAC) versus 53% (SDAC) for patients aged 50 to 64 (age-adjusted one-tailed P = .96). With a median follow-up time of 51 months, survival was not significantly better with HDAC (P = .41); the estimated survival rate at 4 years was 32% (HDAC) versus 22% (SDAC) for those aged less than 50, and 13% (HDAC) versus 11% (SDAC) for those aged 50 to 64. However, relapse-free survival was somewhat better following HDAC Induction (P = .049): 33% (HDAC) versus 21% (SDAC) at 4 years for those aged less than 50, and 21% (HDAC) versus 9% (SDAC) for those aged 50 to 64. Induction with HDAC was associated with a significantly increased risk of fatal (P = .0033) and neurologic (P < .0001) toxicity. Among patients who achieved CR with SDAC, survival and disease-free survival (DFS) following consolidation randomization were not significantly better with HDAC compared with SDAC (P = .77 and .46, respectively). Patients who received both HDAC induction and consolidation had the best postremission outcomes; however, the proportion of CR patients who did not go on to protocol consolidation therapy was more than twice as high after HDAC induction compared with SDAC. Induction therapy with HDAC plus DNR was associated with greater toxicity than SDAC plus DNR, but with no improvement in CR rate or survival. Following CR induction with SDAC, consolidation with HDAC increased toxicity but not survival or DFS. In a nonrandomized comparison, patients who received both HDAC induction and consolidation had superior survival and DFS compared with those who received SDAC induction with either SDAC or HDAC consolidation.

A controlled trial of long-term administration of intravenous immunoglobulin to prevent late infection and chronic graft-vs.-host disease after marrow transplantation: clinical outcome and effect on subsequent immune recovery

To determine whether intravenous immunoglobulin (IVIg) given monthly from day 90 to day 360 posttransplantation decreased the incidence of late infection, chronic graft-vs.-host disease (GVHD), and obliterative bronchiolitis after marrow transplantation, patients were assigned randomly to receive either IVIg (500 mg/kg/month) or no IVIg prophylaxis. Participants were registered before transplantation, and 250 patients (123 IVIg and 127 control) were evaluable for events after day 100. The two groups were balanced for age, marrow source, cytomegalovirus (CMV) seropositivity, pretransplantation conditioning, and prophylaxis for infection and GVHD. Between days 100 and 365 posttransplantation, the incidence of bacteremia or septicemia per 100 patient-days of risk was 0.10 in the IVIg group and 0.12 in the controls (p = not significant). During the same period, the incidence of localized infection was marginally higher in control patients than in IVIg recipients (0.44 vs. 0.24, respectively; relative risk [RR] 1.46, p < 0.07). Administration of IVIg prophylaxis had no effect on survival, the incidence of obliterative bronchiolitis, severity of airflow obstruction, or the incidence or mortality of chronic GVHD. After discontinuing IVIg prophylaxis at day 360, subsequent recovery of endogeneous humoral immunity was impaired (serum IgG1 and IgA levels were significantly lower than controls at day 730), and total infections were less common in the second year in control patients than in former IVIg recipients (0.12 vs 0.19, respectively; RR 0.61, p = 0.03). We conclude that in the absence of hypogammaglobulinemia, monthly administration of IVIg given from day 90 to 360 does not reduce late complications and may impair long-term humoral immune recovery after marrow transplantation.

The biological significance of the multidrug resistance gene MRP in inversion 16 leukemias

Multidrug resistance represents an important mechanism by which leukaemic and solid tumour cells escape cell death after exposure to anthracyclines and other natural products. Acute myeloid leukaemia (AML) associated with the inversion chromosome 16: inv(16)(p13q22) has a favourable prognosis and is known to be chemosensitive. The inversion chromosome is seen in a number of FAB subclasses but is most commonly associated with acute myelomonocytic leukaemia with abnormal eosinophils, M4Eo. It results in the creation of a fusion between the myosin heavy chain gene (MYH11) on the short arm and the gene for a transcription factor, core binding factor beta (CBFB) on the long arm. In a subset of these inv(16) AML patients, inversion also results in loss of the gene for the multidrug resistance protein (MRP) at the short arm breakpoint. This gene maps to 16p13.13, centromeric to the primary short arm breakpoint, separated from MYH11 by a distance of approximately 150kb. Deletion of the MRP gene has been demonstrated by in situ hybridisation, gene dosage studies and by loss of heterozygosity of a flanking microsatellite marker (D16S405). Twenty two patients with inv(16) leukaemia were analysed for deletion of the MRP gene. Deletion of the gene was detected in seven patients, fourteen patients showed retention of the gene and in one case the findings were indeterminate. Clinical data from 13 of these patients were analysed revealing deletion of the MRP gene to be significantly associated with longer time from diagnosis until failure (death or relapse from complete remission) in these patients (p = 0.007). From this work and the growing literature concerning MRP, it appears likely that the deletion of an MRP allele, may favourably affect the biology of inv(16) AML and may have important prognostic implications.

Childhood brain tumor occurrence in relation to residential power line configurations, electric heating sources, and electric appliance use

To assess the relation between childhood brain tumor occurrence and exposure to potential sources of residential magnetic fields, a population-based case-control study of incident brain tumors was conducted in the Seattle, Washington, area at the Fred Hutchinson Cancer Research Center from 1989 to 1994 among children younger than age 20 years who were diagnosed from 1984 to 1990. The specific aims were to evaluate whether proximity to high-current residential power lines, as defined by the Wertheimer-Leeper code, or use of electric appliances or electric heating sources by the mother while pregnant or by the child before diagnosis were associated with increased risks of brain tumor occurrence. The mothers of 133 cases and 270 controls (recruited by random digit dialing) participated. Risk of brain tumor occurrence did not increase with increasing exposure, as indicated by the five-level Wertheimer-Leeper code. When exposure was dichotomized as high versus low, the odds ratio was 0.9 (95% confidence interval 0.5-1.5) and did not vary significantly by sex, age, or histology. No elevations in risk were found for ever versus never use of electric blankets, water beds, or electric heating sources. Odds ratios were slightly elevated for nine appliances and were at or below 1.0 for eight others. These data do not support the hypothesis that exposure to magnetic fields from high-current power lines, electric heating sources, or electric appliances is associated with the subsequent occurrence of brain tumors in children.

Correlation of multidrug resistance (MDR1) protein expression with functional dye/drug efflux in acute myeloid leukemia by multiparameter flow cytometry: identification of discordant MDR-/efflux+ and MDR1+/efflux- cases

Resistance to chemotherapy is a major factor limiting successful treatment of acute myeloid leukemia (AML); one of the best characterized drug resistance mechanisms is extrusion of drugs by the energy-dependent multidrug resistance (MDR1) transport protein. Expression of MDR1 is common in AML and has been linked to lower remission induction rates and decreased remission durations. Because MDR1 efflux function may be modified by drugs such as cyclosporin A, accurate identification of MDR1+/efflux+ AML cases will be critical to identify patients who may benefit from therapies that contain such MDR1 modulators. We have optimized single and multiparameter flow cytometric assays to detect efflux of drugs or fluorescent dyes by previously cryopreserved AML blasts. These assays allowed precise identification of efflux by leukemic blasts, and correlation with CD34 and MDR1 expression. We subsequently studied a series of 60 previously untreated AML cases. Functional efflux was identified in 39 cases and was significantly correlated with MDR1 expression (P = .0002). However, discrepant cases were identified; 10 cases were efflux+ without significant MDR1 expression, whereas 6 MDR1+ cases were efflux-. There was also a highly significant correlation of efflux with CD34; 31 (79%) of the 39 efflux+ cases were CD34+ in comparison with only 5 (24%) of the 21 efflux- cases (P < .0001). Multivariate analysis showed that efflux was significantly associated with independent effects of both CD34 (P = .0011) and MDR1 expression (P = .034); the majority of efflux+ cases were CD34+, whereas 5 of the 6 MDR1+ efflux- cases lacked CD34 expression. Cyclosporin A blocked efflux in all but 2 cases regardless of MDR1 expression. Functional efflux in AML is frequently detected without the classic MDR1+ phenotype indicating that alternate non-MDR1-mediated efflux mechanisms may be important. Efflux assays may better identify patients who would benefit from therapies that include efflux modulators.

Effect of aggressive daunomycin therapy on survival in acute promyelocytic leukemia

The Southwest Oncology Group analyzed outcome with cytotoxic chemotherapy for previously untreated acute myeloblastic leukemia (AML) from 1982 through 1986. Results with acute promyelocytic leukemia (APL) prompted comparison with patients from 1986 through 1991 and analysis of factors contributing to APL results. Patient and disease characteristics and treatment outcome were compared for all evaluable patients, with more detailed analysis of factors affecting APL treatment outcome. From 1982 through 1986, median survival and disease-free survival in 45 APL patients were 106 months and greater than 105 months, respectively, versus 6 and 14 months for 417 other AML patients. Such differences were not seen from 1986 through 1991. In the 141 APL patients from 1982 through 1991, after adjusting for significant patient and disease characteristics, higher daunomycin (DNR) doses during induction were significantly associated with higher complete remission rates (P < .0001), longer survival (P < .0001), and longer DFS (P < .0001). Cytosine arabinoside (Ara-C) induction dose, the inclusion of other chemotherapy agents in induction, postremission therapy (consolidation, maintenance, or bone marrow transplantation) other than DNR, APL subtype, and patient age did not appear to significantly affect outcome of APL, except for a significant detrimental effect of high-dose Ara-C in consolidation (P = .0042). Morphologic AML subtypes other than APL did not affect outcome. We conclude that high-dose DNR selectively increases survival in APL. This good survival is important for evaluation of combined all-trans retinoic acid (ATRA)/chemotherapy protocols and for planning future combinations of chemotherapy and ATRA. These results illustrate the need to individualize chemotherapy for subtypes of AML. Therapeutic response of APL is independent of age. Except for APL, morphologic subclassification of AML contributed little prognostic information.

Effects of vitamin A on survival in patients with chronic myelogenous leukemia: a SWOG randomized trial

A national cooperative group trial was conducted in 153 patients with chronic myelogenous leukemia (CML) in chronic phase treated with oral pulse busulfan to determine if oral vitamin A can increase the time to blast crisis and enhance survival of patients. Patients diagnosed within 1 year and in the chronic phase of CML were randomized to receive oral pulse busulfan or the alkylator plus continuous oral vitamin A. Distributions of clinical progression and overall survival were estimated using the method of Kaplan and Meier. Associations of these endpoints with treatment and other patient characteristics were analyzed using the proportional hazards regression method of Cox. Both regimes were well tolerated. Patients in the busulfan plus vitamin A arm had somewhat longer durations of clinical progression-free survival (median 46 months) and overall survival (51 months) compared to those in the busulfan arm (medians 38 and 44 months). However, the differences were not statistically significant (one-tailed P = 0.11 for clinical progression-free survival, 0.081 for survival). After adjustment for significant factors identified in an additional exploratory multivariate analysis, risk of clinical progression or death was 53% (P = 0.022) greater and risk of death 60% (P = 0.014) greater among busulfan patients. Given the relatively large though non-significant difference between treatment arms, the limited statistical power of the study, and the likelihood that oral vitamin A may not be the most effective means of delivering retinoid therapy, we conclude that further investigation of retinoids in chronic phase CML is warranted.

Carboplatin infusion in relapsed and refractory acute myeloid leukemia--a Southwest Oncology Group trial

Carboplatin (CBDCA) is an active agent in the treatment of acute leukemia and is associated with limited extramedullary toxicity. Simultaneous phase II trials were conducted by the Southwest Oncology Group in adult patients with relapsed or refractory acute myeloid leukemia (AML). CBDCA was given as a continuous infusion at a dose of 300 mg/m2 daily for 5 days. Three (8%) of the 37 eligible patients in the relapsed group achieved complete remissions (CRs) lasting 3, 4, and 26 months. Entry of patients was stopped early in the refractory group due to slow accrual and in the relapsed group due to low CR rate. For both groups combined, the CR rate was 3/45 or 7% (95% confidence interval 3-18%). There were 12 fatal toxicities. Four patients died of intracerebral hemorrhage, three of infection, and five of hepatic and/or renal failure. Nonhematologic grade 4 toxicity included diarrhea in three patients, hyperbilirubinemia in four, and mucositis and renal toxicity in one each. These results suggest that CBDCA should not be considered for treatment of relapsed or refractory AML patients with prior high-dose therapy.

Cytogenetic correlation with disease status and treatment outcome in advanced stage leukemia post bone marrow transplantation: a Southwest Oncology Group study (SWOG-8612)

A retrospective cytogenetic study was performed to determine whether non-random chromosome aberrations were related to the outcome of marrow transplantation for advanced stage acute leukemia (AL) and chronic myelogenous leukemia (CML). The patients were registered on SWOG-8612, a randomized comparison of busulphan and cyclophosphamide (BU/CY) to fractionated total body irradiation and etoposide (FTBI/VP16) as preparatory regimens for allogeneic bone marrow transplant (BMT). Blume K. G., Kopecky K. J., Henslee-Downey J. P., Forman S. J., Stiff P. J., Le Maistre C. F. & Appelbaum F. R. (1987) Blood 81, 2187. Pretreatment cytogenetic studies were available for 90 (78%) of the 115 patients who proceeded to BMT. Patients were categorized by diagnosis (ALL/AML/CML), disease status ['good' risk = second complete remission (CR2) or CML-accelerated phase (AP); 'poor' risk = third complete remission (CR3), induction failure, florid relapse or CML-blast phase (BP)] and cytogenetic status (favorable = normal cytogenetics in AL or Philadelphia chromosome positive (Ph+) standard or variant translocation as the sole findings in CML; unfavorable = all other cytogenetic aberrations). Chromosomal aberrations observed in the unfavorable category included -7, t(9;22) in AL, t(8;21) in association with complex karyotypes, t(6;9), del(9q), t/del(11q), t(1;19), hypotetraploidy, and complex karyotypes (> 3 cytogenetic anomalies). Unfavorable cytogenetic status was significantly more frequent among patients with 'poor' risk clinical disease status (P < 0.0001). In multivariate analysis, disease-free survival (DFS) was significantly poorer for patients with unfavorable cytogenetic status (P = 0.002) but not significantly related to disease status (P = 0.43). These data indicate that certain secondary chromosome aberrations [+8,i(17q), duplication of Ph] should be reclassified as relatively favorable predictors of successful BMT in CML and, therefore, be separated from the unfavorable cytogenetic aberrations characteristic of drug resistant disease [-7, inv(3), complex karyotypes]. The limited number of patients precluded definitive assessment of the prognostic significance of specific cytogenetic aberrations for any single diagnosis. Nevertheless, these findings suggest that cytogenetic status may be an important and independent factor in predicting outcome following allogeneic bone marrow transplantation.

Trisomy 11: an association with stem/progenitor cell immunophenotype

The clinicopathological features and the prognostic significance of acute myeloid leukaemia (AML) with trisomy 11 are currently unknown. In this study we describe 15 adult AML cases with trisomy 11. Trisomy 11 was the sole chromosomal anomaly in eight cases; the remaining seven cases were characterized by +11 in association with other karyotypic aberrations. Patients ages ranged from 34 to 79 years. 12 patients were male; three were female. Although there was no correlation of trisomy 11 with any specific FAB subgroup [M2 (n = 7), M1 (n = 5), M4/5 (n = 2), M3 (n = 1)] less mature forms predominated. Immunologically, the leukaemic blasts showed a strikingly consistent stem cell phenotype with expression of HLA-DR, CD34 and the myeloid antigens (CD15, CD33 and/or CD13). In addition, two cases expressed the B-cell associated antigen CD19. The presence of trilineage dysplasia, suggesting the presence of an underlying myelodysplasia (MDS), was observed at presentation in five cases; in another case MDS was evident at relapse only. Unexpectedly, MLL gene rearrangements were observed in two of four cases characterized by trisomy 11 as the sole karyotypic abnormality; however, MLL aberrations were not identified in three cases with trisomy 11 accompanied by other karyotypic anomalies. The majority of patients in each subgroup (i.e. those with and without additional cytogenetic abnormalities) achieved a short first complete remission (CR) (mean 8 months) and failed to obtain a second CR. Only one patient in each trisomy 11 subgroup is in a continuous CR for > 34 months. These findings suggest that trisomy 11 leukaemia is characterized by a stem/progenitor cell immunophenotype with poor response to standard chemotherapeutic regimens and an unfavourable prognosis.

A prospective evaluation of the roles of allogeneic marrow transplantation and low-dose monthly maintenance chemotherapy in the treatment of adult acute myelogenous leukemia (AML): a Southwest Oncology Group study

Between February 1982 and December 1986, the Southwest Oncology Group conducted a prospective study in patients with newly diagnosed acute myeloid leukemia (AML) with two objectives: to evaluate the role of allogeneic marrow transplantation for patients in first remission, and to evaluate the role of low-dose monthly maintenance therapy in those patients not transplanted in first remission. Among 522 evaluable patients, 295 (57%) achieved complete remission (CR), including 70% of patients age 49 or less. Twenty-four patients (15%) age 49 or less in CR were not HLA-typed, mostly because of financial constraints. HLA-identical donors were found for 39% of patients, of whom two-thirds were transplanted in first CR. The 5-year disease-free survival among those transplanted in first CR, those with donors not transplanted in first CR, and those less than age 50 without donors was 41, 42, and 29%, respectively (P = 0.60). A total of 150 eligible patients were randomized to receive late intensification alone or late intensification plus monthly maintenance. In multivariate analyses, treatment with maintenance was associated with prolonged disease-free survival (P = 0.028), but not improved overall survival (P = 0.27). Factors associated with improved overall survival included younger age, lower white blood count (WBC) at diagnosis, having leukemia of M3 morphology, and being of white race. In this study, a diagnosis of M3 AML was particularly favorable, with disease-free and overall survivals of 75 and 56%, respectively, at 7 years.

Expression of myeloid antigens by blast cells in acute lymphoblastic leukemia of adults. The Southwest Oncology Group experience

A subset of adult acute lymphoblastic leukemia (ALL) patients have blast cells which co-express myeloid-associated antigens (MY+ ALL). We have analyzed 113 adult ALL cases for expression of MY-associated antigens (MAA). ALL was diagnosed by standard morphology, cytochemistry, and immunophenotype in central review. MY+ ALL was diagnosed when > or = 20% of lymphoblasts co-expressed CD13 and/or CD33. Overall incidence of MY+ was 31/113 (27%). MAA expression was not significantly correlated with WBC, blast count, hemoglobin, or hematocrit. MY+ cases were more likely to express B-associated antigens, especially CALLA, and to be FAB L2, Ph+, or to have the BCR-ABL translocation by PCR, but these differences were not statistically significant. All patients were induced with a L10M regimen, and 67 (59%) achieved CR: 43/66 (65%) of B MY neg; 14/29 (48%) of B MY+; 10/16 (63%) T MY neg; and 0/2 T MY+. In age-adjusted analyses CR rate did not differ significantly between MY+ and MY neg patients or between B- and T-cell patients. Of the 113 patients, 84 have died and the remaining 29 patients have been followed for a median of 49 months. In proportional hazards regression analyses adjusting for age and WBC, heterogeneity of survival among the four groups was statistically significant (p = 0.021), largely due to MY status. The mortality rate was 85% greater for MY+ patients compared to MY neg patients (two-tailed p = 0.013). By contrast, survival did not vary significantly between B- and T-cell patients. The data indicate that MAA expression is useful for predicting overall survival of adult patients with ALL treated in a L10M protocol. As a predictive factor MAA expression is comparable to the WBC and superior to the more standard stratification by B- or T-cell markers for this group of patients.

Detection of BCR-ABL fusion genes in adult acute lymphoblastic leukemia by the polymerase chain reaction

The sensitivity and clinical utility of the polymerase chain reaction (PCR) assay for the detection of BCR-ABL gene rearrangement was compared to conventional cytogenetics for the Philadelphia chromosome (Ph1) in adult acute lymphoblastic leukemia (ALL) patients entered onto a single clinical trial. Ninety-three patients had evaluable PCR assays for both the p190bcr-abl and p210bcr-abl type of BCR-ABL gene rearrangements. Twenty-one of 93 patients (23%) were positive for the BCR-ABL rearrangement by the PCR assay. Fourteen of these patients had the p210brc-abl BCR-ABL rearrangement characteristically seen in CML patients, while seven had the p190bcr-abl rearrangement seen in ALL alone. Of 61 patients analyzed, both with conventional cytogenetics and PCR, eight (13%) were positive for the Ph1, while 14 (23%) were positive for the BCR-ABL rearrangement by the PCR assay. Discordance between the PCR assay and cytogenetics occurred in eight cases where the PCR assay was positive and the cytogenetics negative, and two cases where the PCR assay was negative and cytogenetics positive. PCR positivity did not correlate with treatment response, survival, or relapse-free survival, but there was a higher percentage of L2 FAB morphology in the PCR+ cases compared to the PCR-cases (67 vs. 28%, p = 0.003). In addition, the data suggested that patients with a p190bcr-abl rearrangement have a better response to induction therapy, but a worse relapse-free survival compared to patients with a p210bcr-abl breakpoint, but these differences were not statistically significant. These data suggest that PCR and conventional cytogenetics may provide complementary information, since there appear to be a subset of patients who are Ph1-negative yet BCR-ABL positive by PCR. Further studies will be required to determine the prognostic significance of the detailed information about BCR-ABL breakpoints that is available from the PCR assay.

HLA-DR-, CD33+, CD56+, CD16- myeloid/natural killer cell acute leukemia: a previously unrecognized form of acute leukemia potentially misdiagnosed as French-American-British acute myeloid leukemia-M3

We have identified and characterized a previously unrecognized form of acute leukemia that shares features of both myeloid and natural killer (NK) cells. From a consecutive series of 350 cases of adult de novo acute myeloid leukemia (AML), we identified 20 cases (6%) with a unique immunophenotype: CD33+, CD56+, CD11a+, CD13lo, CD15lo, CD34+/-, HLA-DR-, CD16-. Multicolor flow cytometric assays confirmed the coexpression of myeloid (CD33, CD13, CD15) and NK cell-associated (CD56) antigens in each case, whereas reverse transcription polymerase chain reaction (RT-PCR) assays confirmed the identity of CD56 (neural cell adhesion molecule) in leukemic blasts. Although two cases expressed CD4, no case expressed CD2, CD3, or CD8 and no case showed clonal rearrangement of genes encoding the T-cell receptor (TCR beta, gamma, delta). Leukemic blasts in the majority of cases shared unique morphologic features (deeply invaginated nuclear membranes, scant cytoplasm with fine azurophilic granularity, and finely granular Sudan black B and myeloperoxidase cytochemical reactivity) that were remarkably similar to those of acute promyelocytic leukemia (APL); particularly the microgranular variant (FAB AML-M3v). However, all 20 cases lacked the t(15;17) and 17 cases tested lacked the promyelocytic/retinoic acid receptor alpha (RAR alpha) fusion transcript in RT-PCR assays; 12 cases had 46,XX or 46,XY karyotypes, whereas 2 cases had abnormalities of chromosome 17q: 1 with del(17)(q25) and the other with t(11;17)(q23;q21) and the promyelocytic leukemia zinc finger/RAR alpha fusion transcript. All cases tested (6/20), including the case with t(11;17), failed to differentiate in vitro in response to all-trans retinoic acid (ATRA), suggesting that these cases may account for some APLs that have not shown a clinical response to ATRA. Four of 6 cases tested showed functional NK cell-mediated cytotoxicity, suggesting a relationship between these unique CD33+, CD56+, CD16- acute leukemias and normal CD56+, CD16- NK precursor cells. Using a combination of panning and multiparameter flow cytometric sorting, we identified a normal CD56+, CD33+, CD16- counterpart cell at a frequency of 1% to 2% in the peripheral blood of healthy individuals. Our studies suggest that this form of acute leukemia may arise from transformation of a precursor cell common to both the myeloid and NK cell lineages; thus we propose the designation myeloid/NK acute leukemia. Recognition of this new leukemic entity will be important in distinguishing these ATRA-nonresponsive cases from ATRA-responsive true APL.

Deletion of gene for multidrug resistance in acute myeloid leukaemia with inversion in chromosome 16: prognostic implications

Acute myeloid leukaemia (AML) associated with an inversion in chromosome 16 has a relatively favourable prognosis. The AML subclass most commonly associated with this chromosomal abnormality is acute myelomonocytic leukaemia with abnormal eosinophils. In some AML patients with inversion 16 the chromosomal lesion results in deletion of MRP, the gene for multidrug resistance associated protein. This gene is proximal to the primary breakpoint and loss of its function may play a key role in determining the favourable outcome in inversion 16 AML. We have demonstrated deletion of MRP by in situ hybridisation, by gene dosage studies and by studying loss of heterogeneity of a flanking microsatellite marker. Among 13 AML patients with inversion 16 MRP deletion was detected in 5 while 7 had no deletion. Deletion of MRP gene was associated with longer time from diagnosis until death or relapse from complete remission (p = 0.007). These findings provide important insight into the biology of inversion 16 leukaemia and suggest that MRP deletion, as detected by molecular analysis, may have a key role in determining outcome in patients with inversion 16 AML.

Didemnin B in metastatic malignant melanoma: a phase II trial of the Southwest Oncology Group

Didemnin B is a cyclic peptide isolated from the marine tunicate Trididemnin cyanophorum. It is a known potent inhibitor of RNA, DNA and protein synthesis, with activity against the murine B16 melanoma. Fourteen patients with disseminated malignant melanoma were evaluated in a Southwest Oncology Group phase II trial of didemnin B at 4.2 mg/m2 by 30 min i.v. infusion every 28 days (SWOG-8754). Only patients with no prior chemotherapy were eligible; prior radiation therapy, surgery and at most one prior biologic regimen were allowed. Patients with brain metastasis were eligible only if the disease in the brain had been treated and controlled. All patients had to have normal renal and hepatic function and adequate granulocyte and platelet counts, a performance status of 0-2, and bidimensionally measurable disease. Fourteen patients were entered on the study; five received one and nine received two courses of didemnin B. No responses were noted among the 11 patients evaluable for response. Five patients developed unusual but reversible hypersensitivity reactions during the second course of therapy. Other toxicity in this trial was nausea and vomiting and diarrhea, none of severity greater than grade 3. Given the lack of antitumor efficacy and the unusual toxicity, further evaluation of didemnin B in this dose and schedule in malignant melanoma is not warranted.

Evaluation of amonafide in disseminated malignant melanoma. A Southwest Oncology Group study

Amonafide (AMF), NSC 308847 is an investigational anticancer drug acting as a DNA intercalating agent. This paper presents results of a phase II clinical study of AMF in disseminated malignant melanoma. Twenty patients, eleven males and nine females, with biopsy proven malignant melanoma, performance status 0-2; median age 59 (range 29-74), and no previous chemotherapy, were treated with AMF 300 mg/m2/day by 60 min i.v. infusion for five days repeated every three weeks. Fifteen patients had lung (9 patients) and/or liver (8 patients) involvement. None had known brain metastasis at entry. All 20 patients were evaluated for response and toxicity. Six patients had stable disease and fourteen had increasing disease. With 0/20 responses, the upper 95% confidence limit for the response rate was 14%. The median survival time was 5.7 months. Hematologic toxicity was dose limiting with the incidence of leucopenia 45% and thrombocytopenia 20%. The nonhematologic toxicities included nausea and vomiting (60%), alopecia (20%), headaches (15%), diarrhea (10%), and phlebitis (10%). We conclude that AMF administered at this dose and schedule is not active in the treatment of patients with malignant melanoma, previously untreated with chemotherapy.

A prospective randomized comparison of total body irradiation-etoposide versus busulfan-cyclophosphamide as preparatory regimens for bone marrow transplantation in patients with leukemia who were not in first remission: a Southwest Oncology Group study

Two novel preparatory regimens for conditioning of patients with leukemia for allogeneic bone marrow transplantation (BMT) from histocompatible sibling donors have been tested in a phase III trial under the auspices of the Southwest Oncology Group (SWOG 8612). These two regimens consisted either of fractionated total body irradiation and etoposide (FTBI/VP-16) or high-dose busulfan with cyclophosphamide (BU/CY). Only patients who had failed prior conventional management at least once were study eligible, ie, no patients with acute leukemia in first remission (CR) or in first chronic phase (CP) of chronic myelogenous leukemia (CML) participated. Patients were stratified according to the following risk criteria: "good-risk" patients were those who were in second CR of their acute leukemia or in accelerated phase (AP) of CML; "poor-risk" patients had further advanced stages of leukemia. During a 52-month period, 131 patients were registered of whom 122 (93%) were study eligible. Sixty-one eligible patients were randomized to the FTBI/VP-16 arm and 61 to the BU/CY regimen. Of these 122 patients, 114 (93%) proceeded to BMT according to protocol. Posttransplant immunosuppression to prevent graft-versus-host disease (GVHD) consisted of cyclosporine and prednisone (CSA/PSE). Neither overall survival nor disease-free survival (DFS) differed significantly between the two treatment groups (P = .89 and .69, respectively). Estimated DFS for "good-risk" patients who had been prepared with the FTBI/VP-16 regimen was 55% +/- 11%, as compared with patients treated with BU/CY whose DFS figure was 34% +/- 10% (P = .30). For "poor-risk" candidates, the DFS rates at 24 months were 17% +/- 6% (for FTBI/VP-16) and 24% +/- 8% (for BU/CY), respectively (P = .81). These figures do not differ significantly, especially in view of the fact that the "good-risk" patients prepared with the FTBI/VP-16 regimen were younger than those treated with BU/CY. Both regimens were well tolerated with no regimen-related deaths encountered during the 6-week period after BMT. This study also confirmed the efficacy of the CSA/PSE combination in the prevention of GVHD with 23 of 113 (20%) of BMT recipients developing moderate to severe acute GVHD. The leading cause for treatment failure was leukemic relapse (45 of the 114 BMT recipients suffered a recurrence of their leukemia), whereas 38 patients died without evidence of relapse. Thirty-one patients are alive and in continued CR after marrow transplantation; four are alive in relapse.(ABSTRACT TRUNCATED AT 400 WORDS)

Late intensification with POMP chemotherapy prolongs survival in acute myelogenous leukemia--results of a Southwest Oncology Group study of rubidazone versus adriamycin for remission induction, prophylactic intrathecal therapy, late intensification, and levamisole maintenance

Between August 1978 and September 1982, 642 patients with newly diagnosed acute myelogenous leukemia (AML) were entered onto a Southwest Oncology Group Study which addressed four questions. (i) What is the comparative utility of rubidazone versus adriamycin in remission induction? (ii) What is the role of prophylactic intrathecal therapy in AML? (iii) Does late intensification affect treatment outcome? (iv) Does maintenance with levamisole affect disease-free survival or overall survival? Among 611 evaluable patients, 329 (54%) achieved complete remission. There was no difference in the remission rate between those patients receiving rubidazone (54%) and those receiving adriamycin (54%) as part of the induction regimen. Prophylactic intrathecal therapy with cytosine arabinoside had no effect on the incidence of central nervous system disease or survival. After nine months of complete remission, patients were randomized between late intensification with POMP (mercaptopurine + vincristine + methotrexate + prednisone) or continued maintenance with OAP (vincristine + cytosine arabinoside + prednisone). T patients randomized to late intensification had better survival and disease-free survival, compared to those randomized to receive no late intensification (p = 0.027 and 0.030, respectively). At twelve months of remission, surviving patients were randomized to receive levamisole or no further treatment. There was no evidence that levamisole affected survival or disease-free survival.

Analysis of treatment failure in acute nonlymphocytic leukemia patients over fifty years of age. A Southwest Oncology Group study

Fourteen participating centers registered 33 patients on a Southwest Oncology Group Study of adults with acute non-lymphocytic leukemia (ANLL). Induction consisted of cytosine arabinoside 70 mg/m2 days 1-7 by continuous intravenous (i.v.) infusion, VP-16 50 mg/m2 i.v. over 1 hour days 1-3, and daunomycin 30 mg/m2 i.v. bolus days 1-3. Twenty-five patients (median age 69 years) were evaluable for response. Eleven (44%) achieved a remission marrow but only 8 fulfilled both blood and marrow criteria for complete remission. Of the 11 patients with a remission marrow, there were no patients over 70 years of age. Major coexisting disease data were evaluated. Only 5 patients had no major coexisting disease and 4 of those 5 achieved a remission marrow. The study illustrates and underscores the following problems of remission induction in the elderly: (a) increased susceptibility to the stress of the induction period, with 6 patients (24%) dying before treatment day sixteen; (b) disease resistance to antileukemic therapy with persistent ANLL in 6 patients (24%), despite two induction courses; and (c) hematopoietic stem cell sensitivity in the elderly with marrow regeneration failure documented in 2 patients (8%) following induction. Acute nonlymphocytic leukemia in the elderly has a poor prognosis, and novel therapeutic approaches are warranted.

On estimating HLA/disease association with application to a study of aplastic anemia

A multiplicative model is described relating HLA typing information to disease incidence. A likelihood-based method for estimating parameters in this model is proposed for use with data sets in which HLA haplotype information is available on a series of cases and their parents. This approach is extended to incorporate information from a matched control series for the purpose of estimating HLA and environmental risk factor effects simultaneously. The method is applied to data from aplastic anemia patients treated by bone marrow transplantation and the results are compared to unmatched case-control analyses using the same case series and several different control series.

Immunomodulatory and antimicrobial efficacy of intravenous immunoglobulin in bone marrow transplantation

BACKGROUND

Graft-versus-host disease (GVHD) and infection are major complications of allogeneic bone marrow transplantation. Since intravenous immunoglobulin has shown benefit in several immunodeficiency and autoimmune disorders, we studied its antimicrobial and immunomodulatory role after marrow transplantation.

METHODS

In a randomized trial of 382 patients, transplant recipients given immunoglobulin (500 mg per kilogram of body weight weekly to day 90, then monthly to day 360 after transplantation) were compared with controls not given immunoglobulin. By chance, the immunoglobulin group included more patients with advanced-stage neoplasms; otherwise, the study groups were balanced for prognostic factors.

RESULTS

Control patients seronegative for cytomegalovirus who received seronegative blood products remained seronegative, but seronegative patients who received immunoglobulin and screened blood had a passive transfer of cytomegalovirus antibody (median titer, 1:64). Among the 61 seronegative patients who could be evaluated, none contracted interstitial pneumonia; among the 308 seropositive patients evaluated, 22 percent of control patients and 13 percent of immunoglobulin recipients had this complication (P = 0.021). Control patients had an increased risk of gram-negative septicemia (relative risk = 2.65, P = 0.0039) and local infection (relative risk = 1.36, P = 0.029) and received 51 more units of platelets than did immunoglobulin recipients. Neither survival nor the risk of relapse was altered by immunoglobulin. However, among patients greater than or equal to 20 years old, there was a reduction in the incidence of acute GVHD (51 percent in controls vs. 34 percent in immunoglobulin recipients; P = 0.0051) and a decrease in deaths due to transplant-related causes after transplantation of HLA-identical marrow (46 percent vs. 30 percent; P = 0.023).

CONCLUSIONS

Passive immunotherapy with intravenous immunoglobulin decreases the risk of acute GVHD, associated interstitial pneumonia, and infections after bone marrow transplantation.