Stimulation of chronic lymphocytic leukemia cells with CpG oligodeoxynucleotide gives consistent karyotypic results among laboratories: a CLL Research Consortium (CRC) Study.

Cytogenetic abnormalities are important prognostic indicators in CLL. Historically, only interphase cytogenetics was clinically useful in CLL, because traditional mitogens are not effective mitotic stimulants. Recently, CpG-oligodeoxynucleotide (ODN) stimulation has shown effectiveness in CLL cells. The CLL Research Consortium tested the effectiveness and reproducibility of CpG-ODN stimulation for detecting chromosomally abnormal clones by five laboratories. More clonal abnormalities were observed after culture of CLL cells with CpG-ODN than with the traditional pokeweed mitogen plus 12-O-tetradecanoylphorbol-13-acetate (PWM+TPA). All clonal abnormalities in PWM+TPA cultures were observed in CpG-ODN cultures, whereas CpG-ODN identified some clones not found by PWM+TPA. CpG-ODN stimulation of one normal control sample and 12 CLL samples showed that, excepting clones of del(13q) in low frequencies and one translocation, results in all five laboratories were consistent, and all abnormalities were concordant with FISH. Abnormal clones in CLL were more readily detected with CpG-ODN stimulation than with traditional B-cell mitogens. With CpG-ODN stimulation, abnormalities were reproducible among cytogenetic laboratories. CpG-ODN did not appear to induce aberrations in cell culture, but did enhance detection of abnormalities and complexity in CLL. Because karyotypic complexity is prognostic and is not detectable by standard FISH analyses, stimulation with CpG-ODN is useful for identifying this additional prognostic factor in CLL.

Central review of cytogenetics is necessary for cooperative group correlative and clinical studies of adult acute leukemia: the Cancer and Leukemia Group B experience.

The Cancer and Leukemia Group B has performed central review of karyotypes submitted by institutional cytogenetics laboratories from patients with acute myeloid (AML) and acute lymphoblastic (ALL) leukemia since 1986. We assessed the role of central karyotype review in maintaining accurate, high quality cytogenetic data for clinical and translational studies using two criteria: the proportion of karyotypes rejected (i.e. inadequate), and, among accepted (i.e. adequate) cases, the proportion of karyotypes whose interpretation was changed on central karyotype review. We compared the first four years during which central karyotype review was performed with a recent 4-year period and found that the proportion of rejected samples decreased significantly for both AML and ALL. However, during the latter period, central karyotype reviews still found 8% of AML and 16% of ALL karyotypes inadequate. Among adequate cases, the karyotype was revised in 26% of both AML and ALL samples. Some revisions resulted in changing the patients' assignment to particular World Health Organization diagnostic categories and/or moving patients from one prognostic group to another. Overall, when both data on rejection rates and data on karyotype revisions made in accepted cases were considered together, 32% of AML and 38% of ALL samples submitted were either rejected or revised on central karyotype review during the recent 4-year period. These data underscore the necessity of continued central karyotype review in multi-institutional cooperative group studies.

Outcome of induction and postremission therapy in younger adults with acute myeloid leukemia with normal karyotype: a cancer and leukemia group B study.

PURPOSE: Evaluate the outcome of induction and postremission therapy in adults younger than 60 years with normal cytogenetics acute myeloid leukemia (AML). PATIENTS AND METHODS: In 490 patients, induction included cytarabine and daunorubicin (AD) or cytarabine and escalated doses of daunorubicin and etoposide +/- PSC-833 (ADE/ADEP). Intensification included one cycle of high-dose cytarabine (HDAC) followed by etoposide/cyclophosphamide and mitoxantrone/diaziquone (group I), three HDAC cycles (group II), four intermediate-dose cytarabine (IDAC) or HDAC cycles (group III), or one HDAC/etoposide cycle and autologous stem-cell transplantation (ASCT; group IV). RESULTS: Of 350 patients receiving AD, 73% achieved complete remission (CR), compared with 82% of 140 receiving ADE/ADEP (P = .04). Splenomegaly was associated with a lower CR rate (P < .001), and ADE/ADEP, with a higher CR rate in younger patients (P = .005). The 5-year disease-free survival (DFS) rate was 28% each for intensification groups I and II, compared with 41% and 45% for groups III and IV, respectively (P = .02). The 5-year cumulative incidence of relapse (CIR) was 62% and 67% for groups I and II, respectively, compared with 54% and 44% for groups III and IV, respectively (P = .049). The type of postremission intensification remained significant for DFS and CIR in multivariable analysis. CONCLUSION: In younger adults with normal cytogenetics AML, splenomegaly predicts a lower CR rate, and the postremission strategies of either four cycles of I/HDAC or one cycle of HDAC/etoposide followed by ASCT are associated with improved DFS and reduced relapse compared with therapies that include fewer cycles of cytarabine or no transplantation.

Abnormal cytogenetics at date of morphologic complete remission predicts short overall and disease-free survival, and higher relapse rate in adult acute myeloid leukemia: results from cancer and leukemia group B study 8461.

PURPOSE: As most patients with acute myeloid leukemia (AML) with morphologic complete remission (CR) ultimately relapse, better predictors for outcome are needed. Recently, Cheson et al suggested using cytogenetic remission (CRc) as part of the criteria for CR. To our knowledge, ours is the first relatively large study evaluating the usefulness of CRc attained immediately following induction chemotherapy. PATIENTS AND METHODS: We included AML patients treated on Cancer and Leukemia Group B front-line studies with cytogenetic samples obtained at diagnosis and at the first day of documented CR following induction. Patients with abnormal cytogenetics at diagnosis, and normal cytogenetics at CR (NCR; n = 103) were compared with those with abnormal cytogenetics both at diagnosis and at CR (ACR; n = 15) for overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR). Cox proportional hazards models determined the prognostic significance of cytogenetics at CR, adjusting for other covariates. RESULTS: Clinical features were similar for both groups, with the exception of favorable cytogenetics [t(8;21), inv(16)/t(16;16), t(15;17)] at diagnosis, which was more frequent (P =.03) in the NCR group. Median follow-up was 3.1 years (range, 1.0 to 11.4 years). ACR patients had significantly shorter OS (P =.006) and DFS (P =.0001), and higher CIR (P =.0001). In multivariable models, the NCR and ACR groups were predictors for OS (P =.03), DFS (P =.02), and CIR (P =.05). The relative risk of relapse or death was 2.1 times higher for ACR patients than for NCR patients (95% CI, 1.1 to 3.9). CONCLUSION: Our data suggest that converting to normal karyotype at the time of first CR is an important prognostic indicator and support the use of CRc as a criterion of CR in AML.

Repetitive cycles of high-dose cytarabine benefit patients with acute myeloid leukemia and inv(16)(p13q22) or t(16;16)(p13;q22): results from CALGB 8461.

PURPOSE: To study the impact of repetitive (three to four courses) versus a single course of high-dose cytarabine (HDAC) consolidation therapy on outcome of patients with acute myeloid leukemia (AML) and inv(16)(p13q22) or t(16;16)(p13;q22). PATIENTS AND METHODS: We examined the cumulative incidence of relapse (CIR), relapse-free survival (RFS), and overall survival (OS) for 48 adults younger than 60 years with inv(16)/t(16;16) who had attained a complete remission on one of four consecutive clinical trials and were assigned to receive HDAC consolidation therapy. Twenty-eight patients were assigned to either three or four courses of HDAC, and 20 patients were assigned to one course of HDAC followed by alternative intensive consolidation therapy. RESULTS: Pretreatment features were similar for the two groups. The CIR was significantly decreased in patients assigned to receive three to four cycles of HDAC compared with patients assigned to one course (P=.03; 5-year CIR, 43% v 70%, respectively). The difference in RFS also approached statistical significance (P=.06). In a multivariable analysis that adjusted for potential confounding covariates, only treatment assignment (three to four cycles of HDAC) predicted for superior RFS (P=.02). The OS of both groups was similar (P=.93; 5-year OS, 75% for the three to four cycles of HDAC group v 70% for the one cycle of HDAC group), reflecting a high success rate with stem-cell transplantation salvage treatment administered among patients in both treatment groups. CONCLUSION: We conclude that, in AML patients with inv(16)/t(16;16), repetitive HDAC therapy decreases the likelihood of relapse compared with consolidation regimens including less HDAC.

Pretreatment cytogenetic abnormalities are predictive of induction success, cumulative incidence of relapse, and overall survival in adult patients with de novo acute myeloid leukemia: results from Cancer and Leukemia Group B (CALGB 8461).

We analyzed prospectively 1213 adults with de novo acute myeloid leukemia (AML) to ascertain the prognostic impact of cytogenetic abnormalities on complete remission (CR) rate, 5-year cumulative incidence of relapse (CIR), and 5-year overall survival (OS). All patients received similar induction therapy. Median follow-up for surviving patients was 8.3 years. Nonprioritized cytogenetics distinguished t(8;21) and inv(16)/t(16;16) as conferring a significantly better prognosis than normal karyotype. Prognostic impact of many abnormalities could not be determined independently because of their association with complex karyotype. Neither complex karyotype nor secondary aberrations affected outcome of patients with t(8;21), inv(16)/t(16;16), or t(9;11). Among other patients, those with complex karyotypes had significantly worse outcomes than cytogenetically normal patients. Based on outcome for specific cytogenetic abnormalities and karyotype complexity, patients were divided into 3 risk groups: favorable (CR 88%, CIR 54%, OS 55%), intermediate (CR 67%, CIR 67%, OS 24%), and adverse (CR 32%, CIR 92%, OS 5%). Multivariate analyses confirmed the major contribution of cytogenetics to the probability of attaining CR, CIR, and OS. For the adverse-risk group, the probability of achieving CR was 4.0 and 11.9 times lower, the probability of relapse 3.0 and 4.4 times higher, and the risk of death 2.1 and 4.3 times higher than those for the intermediate and favorable groups, respectively. We conclude that although the prognostic impact of many recurring abnormalities has not been ascertained independently of complex karyotype, cytogenetics is among the most useful factors predicting attainment of CR, CIR, and long-term survival in adult AML.