Reproducible cytogenetic analysis in CLL has been limited by the inability to obtain reliable metaphase cells for analysis. CpG oligonucleotide and cytokine stimulation have been shown to improve metaphase analysis of CLL cytogenetic abnormalities, but is limited by variability in the cytokine receptor levels, stability and biological activity of the cytokine in culture conditions and high costs associated with these reagents. We report here use of a novel, stable CpG, GNKG168 along with pokeweed mitogen (PWM) and phorbol 12-myristate 13-acetate (PMA) for conventional cytogenetic assessment in CLL. We demonstrate that the combined use of GNKG168+PWM/PMA increased the sensitivity of detection of chromosomal abnormalities compared to PWM/PMA (n=207, odds ratio=2.2, p=0.0002) and GNKG168 (n=219, odds ratio=1.5, p=0.0452). Further, a significant increase in sensitivity to detect complexity ≥3 with GNKG168+PWM/PMA compared to GNKG168 alone (odds ratio 8.0, p=0.0022) or PWM/PMA alone (odds ratio 9.6, p=0.0007) was observed. The trend toward detection of higher complexity was significantly greater with GNKG168+PWM/PMA compared to GNKG168 alone (p=0.0412). The increased sensitivity was mainly attributed to the addition of PWM/PMA with GNKG168 because GNKG168 alone showed no difference in sensitivity for detection of complex abnormalities (p=0.17). Comparison of fluorescence in situ hybridization (FISH) results with karyotypic results showed a high degree of consistency, although some complex karyotypes were present in cases with no adverse FISH abnormality. These studies provide evidence for potential use of GNKG168 in combination with PWM and PMA in karyotypic analysis of CLL patient samples to better identify chromosomal abnormalities for risk stratification.
Key Points• Pretreatment near-tetraploidy is associated with advanced Rai stage, deletion of 17p, and complex karyotype.• Pretreatment near-tetraploidy is an independent risk factor for ibrutinib discontinuation via Richter transformation.Ibrutinib is a highly effective targeted therapy for chronic lymphocytic leukemia (CLL).However, ibrutinib must be discontinued in a subset of patients due to progressive CLL or transformation to aggressive lymphoma (Richter transformation). Transformation occurs early in the course of therapy and has an extremely poor prognosis. Thus, identification of prognostic markers associated with transformation is of utmost importance. Neartetraploidy (4 copies of most chromosomes within a cell) has been reported in various lymphomas, but its incidence and significance in CLL has not been described. Using fluorescence in situ hybridization, we detected near-tetraploidy in 9 of 297 patients with CLL prior to beginning ibrutinib treatment on 1 of 4 clinical trials (3.0%; 95% confidence interval [CI], 1.4%-5.7%). Near-tetraploidy was associated with aggressive disease characteristics: Rai stage 3/4 (P 5 .03), deletion 17p (P 5 .03), and complex karyotype (P 5 .01). Neartetraploidy was also associated with ibrutinib discontinuation due to Richter transformation (P , .0001), but not due to progressive CLL (P 5 .41). Of the 9 patients with near-tetraploidy, 6 had Richter transformation with diffuse large B-cell lymphoma. In a multivariable model, near-tetraploidy (hazard ratio [HR], 8.66; 95% CI,; P , .0001) and complex karyotype (HR, 4.77; 95% CI,; P 5 .01) were independent risk factors for discontinuing ibrutinib due to transformation. Our results suggest that near-tetraploidy is a potential prognostic marker for Richter transformation to assess in patients going on ibrutinib. IntroductionIbrutinib is a first-in-class oral covalent inhibitor of Bruton tyrosine kinase (BTK) 1 approved to treat chronic lymphocytic leukemia (CLL), mantle cell lymphoma, and Waldenstrom macroglobulinemia. Ibrutinib has rapidly changed the landscape of CLL treatment, with high response rates and prolonged remission durations in both relapsed/refractory CLL and previously untreated patients.2-5 Despite these strides, a subset of patients relapse on ibrutinib. Patients relapse primarily with progressive CLL or Richter transformation, an aggressive transformation into lymphoma, predominantly diffuse large B-cell lymphoma.6 Most patients progressing with CLL acquire mutations in either the C481 ibrutinib-binding pocket of BTK or downstream activating mutations in PLCG2 that bypass the need for signaling through BTK. progress via disease transformation. 6 Identifying prognostic markers associated with Richter transformation is critical at this time as an increasing number of patients have begun to receive ibrutinib and those whose CLL transforms have very aggressive disease and poor prognosis. 6,9 Complex karyotype ($3 unrelated chromosomal abnormalities) has been associated with ibrutinib discontinuation due to progr...
Mutations of the IGH variable region in patients with chronic lymphocytic leukemia (CLL) are associated with a favorable prognosis. Cytogenetic complexity (>3 unrelated aberrations) and translocations have been associated with an unfavorable prognosis. While mutational status of IGHV is stable, cytogenetic aberrations frequently evolve. However, the relationships of these features as prognosticators at diagnosis are unknown. We examined the CpG-stimulated metaphase cytogenetic features detected within one year of diagnosis of CLL and correlated these features with outcome and other clinical features including IGHV. Of 329 untreated patients, 53 (16.1%) had a complex karyotype, and 85 (25.8%) had a translocation. Median time to first treatment (TFT) was 47 months. In univariable analyses, significant risk factors for shorter TFT (p<0.05) were Rai stage 3-4, beta2-microglobulin >3.5, log-transformed WBC, unmutated IGHV, complex karyotype, translocation, and FISH for trisomy 8, del(11q) and del(17p). In multivariable analysis, there was significant effect modification of IGHV status on the relationship between translocation and TFT (p=0.002). In IGHV mutated patients, those with a translocation had over 3.5 times higher risk of starting treatment than those without a translocation (p<0.001); however, in IGHV unmutated patients, a translocation did not significantly increase the risk of starting treatment (HR 1.00, p=0.99). Rai Stage 3-4, log-transformed WBC and complex karyotype remained statistically significant; however, del(17p) did not (p=0.51). In summary, the presence of a translocation in IGHV mutated patients appeared to negate the improved prognosis of mutated IGHV, but 4 the presence of a translocation did not have an effect on TFT in high-risk IGHV unmutated patients.
Summary A jumping translocation (JT) is a rare cytogenetic aberration that can occur in haematological malignancy. It involves the translocation of the same fragment of donor chromosome onto two or more recipient chromosomes, typically in different cells. In this study, we describe the first series of chronic lymphocytic leukaemia (CLL) patients with JTs reported to date. Following a review of 878 CLL patient karyotypes, we identified 26 patients (3%) with 97 JTs. The most commonly occurring breakpoint in these translocations was 17p11.2. Loss of TP53 was identified prior to or at the same time as JT in 23 of 26 patients (88%). All patients eventually developed a complex karyotype. All but one patient has required treatment for CLL, with estimated median time to treatment of 11.5 months. This study establishes JTs as a recurrent abnormality found in CLL patients with aggressive disease. JTs contribute to complex karyotypes and, in many cases, are involved in chromosomal rearrangements that result in loss of the tumour suppressor gene TP53.
Chronic Lymphocytic Leukemia (CLL) has a varied clinical course; some patients experience a long survival and others succumb to disease in a short time. Clinical factors correlated with either time to first treatment (TFT) and/or overall survival include Rai stage, IGHV somatic hypermutation status, fluorescence in situ hybridization (FISH) abnormalities, especially del(17p), karyotypic complexity and the presence of a cytogenetic translocation. Previous studies have included patients both at diagnosis and at various times throughout their diseases, and many included limited numbers of patients, precluding extensive analyses of relationships between the prognostic factors and their relative impact on clinical outcome. We sought to identify which factors determined within a short time of diagnosis (i.e., 1 year) were prognostic for TFT in untreated CLL patients. We identified 329 untreated CLL patients who had stimulated karyotypic and FISH analyses within 1 year of diagnosis seen at The Ohio State University (OSU). Patient characteristics and outcome were obtained from patient records. The studies were approved by the OSU IRB and were conducted according to the Declaration of Helsinki. A complex karyotype was defined as ≥ 3 unrelated aberrations by karyotype. Patient characteristics are given in Table 1. Translocations occurred in 87 (26.4%) patients: 38 balanced and 49 unbalanced translocations. Initial statistical analyses showed no large difference in TFT between balanced and unbalanced translations, so they were combined for final analyses. 144 patients (49 with and 95 without a translocation) had unmutated IGHV, and 144 patients (22 with and 122 without a translocation) had mutated IGHV. IGHV data were not available for 41 patients. TFT was calculated from date of diagnosis to date of first treatment. Untreated patients were censored at last known untreated date. Kaplan-Meier curves estimated TFT probability, and proportional hazard models were used to examine the association between potential risk factors and TFT. Using backward selection, variables with statistical significance when adjusting for all other covariates were included in the final model. To evaluate potential effect modifications, pairwise interactions among all the variables in the final model were examined and retained if statistically significant. Stata 14 (College Station TX) was used, and all tests were two-sided with statistical significance set at p<0.05. Median follow-up for censored patients was 30 months (range 0.03-102 months). Median TFT for the entire cohort was 47 months (95% confidence interval (CI) 40-63 months). In a univariable model, the following factors were significant: presence of a translocation (hazard risk (HR) 2.69, CI 1.91-3.78, p<0.001), Rai stage III/IV (HR 3.73, CI 2.32-5.99, p<0.001), complexity (HR 2.92, CI 1.98-4.31, p<0.001), unmutated IGHV (HR 3.54, CI 2.42-5.17, p<0.0001), del17p (HR 2.10, CI 1.31-3.37, p=0.002), del11q (HR 2.91,CI 1.92-4.40, p<0.001). In the multivariable model, there was significant effect modification of IGVH status on the relationship between translocation and TFT (p<0.001). In IGHV mutated patients, those with a translocation had over 5 times the risk of starting treatment relative to those without a translocation (HR 5.30, CI 2.76-10.17); however, in IGHV unmutated patients, a translocation did not significantly increase the risk of starting treatment (HR 1.32, CI 0.86-2.03). Independent of IGHV and translocation, Rai Stage (HR 2.07, CI 1.24-3.45, p=0.01) and del11q (HR 1.68, CI 1.09-2.60, p=0.02) were the only variables that remained statistically significant. Notably, once these variables were accounted for in the model, complexity did not provide additional significant prognostic information (p=0.12), perhaps due to its strong association with a translocation (p<0.001). In summary, the presence of a translocation in IGHV mutated patients appeared to negate the improved prognosis associated with mutated IGHV, but the presence of a translocation did not have an effect on TFT in high-risk IGHV unmutated patients (Figure 1). Table 1 Table 1. Figure 1 Time to Treatment for patients with vs without a translocation and with mutated vs unmutaed IGVH Figure 1. Time to Treatment for patients with vs without a translocation and with mutated vs unmutaed IGVH Disclosures Jones: Pharmacyclics, LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Andritsos:Hairy Cell Leukemia Foundation: Research Funding. Woyach:Morphosys: Research Funding; Acerta: Research Funding; Karyopharm: Research Funding. Awan:Pharmacyclics: Consultancy; Novartis Oncology: Consultancy; Innate Pharma: Research Funding.
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