Greaves, Andrew

Abstract Approximately 10–15% of patients with CLL report a family history (FH) of CLL or a related lymphoproliferative disorder. Whether the biologic features of CLL that occurs within families differ from those that occur sporadically is unknown. A recent study addressing this question has reported that mutated IgVH is significantly more common among familial than sporadic CLL, 68% vs 47%, although the distribution of VH genes used was similar (Blood111:5691, 2008). Therefore we compared IgVH mutational status and gene usage, as well as other biologic features, between familial and sporadic CLL derived from patients enrolled on the CLL Research Consortium (CRC) Tissue Core. Of 4533 patients enrolled in the CRC database and tissue bank, 3328 had adequate family history information, and these were subdivided into 4 groups: FH of CLL (n=468), FH of other heme cancer but not CLL (n=421), FH of non-heme cancer (n=1444), and sporadic cases (no FH of any cancer) (n=995). Of those patients reporting a FH of CLL, 63% had at least one affected 1st degree relative, 20% at least one affected 2nd or greater degree relative, and 17% unknown. 68% of those reporting a FH of CLL also had other cancers in their family. Patients reporting a FH of CLL or non-CLL heme cancers were more frequently white (91%), compared to 87% of those with FH non-heme cancer and 84% of sporadic CLL patients (p=0.005). The proportion of CLL cases that were female was similar among groups, at 37.6% of patients with FH CLL, as compared to 32.5% of sporadic patients (p=0.12). The age at diagnosis of CLL also did not differ among the four groups, although a trend toward a difference was observed between the FH CLL patients, whose mean age at diagnosis was 54.9 (range 30, 93), and the sporadic patients, whose mean age at diagnosis was 56.1 (range 30, 84) (p=0.08). No significant difference was observed among groups in the frequency of IgVH mutation (defined as <98% homology to the most similar germline VH gene), which was present in 50.3% (95% CI 44.5–56.2) of patients with FH CLL, 56.3% (95% CI 49.7–62.7) of patients with FH other heme cancer, 51.9% (95% CI 48.5–55.3) of patients with FH non-heme cancer, and 51.3% (95% CI 47.0–55.5) of sporadic patients (p=0.53). The pattern of IgVH family gene usage also did not differ among the groups; the VH3 subgroup was most commonly used, at 45%, 52%, 46% and 47% of patients with FH CLL, FH other heme cancer, FH non-heme cancer and sporadic, respectively. The VH1 subgroup was next most common in all 4 groups, at 28%, 24%, 26% and 25%, respectively, followed by the VH4 subgroup, at 19%, 17%, 21% and 21%. In addition, no significant difference was observed in the distribution of ZAP-70 expression amongst the four family history subgroups (mean %ZAP-70 expression, 22.8% for FH CLL patients and 24.4% for sporadic patients, p=0.31), or in the fraction considered ZAP-70 positive (>20% expression), which was 40% for FH CLL patients and 45% for sporadic patients (p=0.16). The relative expression of CD23 and CD38 did not differ among groups, nor did levels of beta-2-microglobulin or IgG determined at time of CRC enrollment. Time from diagnosis to initial treatment for each of the subgroups is currently being analyzed. These data on patterns of biologic risk factors in this large group of familial CLLs compared to sporadic CLLs suggest that familial and sporadic CLL are biologically similar and therefore likely to have similar pathogenetic mechanisms, including perhaps an underlying genetic susceptibility.

Abstract Fluorescence in situ hybridization (FISH) probes and analysis methods for B-cell Chronic Lymphocytic Leukemia (CLL) vary extensively among cytogenetic laboratories. This is not unexpected, as neither national nor international standards have been established for most FISH studies. Lack of standardization is problematic when data collected at multiple institutions are used for clinical correlative studies. To circumvent such problems, the five participating laboratories in the CLL Research Consortium (CRC) designed and executed a joint CLL FISH validation study. Methods: Initially a survey was sent to assess equipment, methods and experience with FISH for CLL. In a pilot study to compare laboratory performance in scoring patient samples, slides from ten patients were prepared and sent to each participating lab to be hybridized with five probe sets (= 50 hybridizations) and analyzed according to their local protocol. In a second pilot study, slides from two patient samples and identical probe sets were sent to the participating labs where hybridization and analysis were carried out according to their local protocol. Next, technologists and directors from all participating labs attended a workshop where technologists working in pairs scored nuclei together, techniques and scoring criteria were established, and consensus reached on other concerns. In a proficiency test nine months after the workshop, slides from two patient samples (10 hybridizations) were hybridized and scored according to each lab’s protocol and results shared using a common reporting form. Results: Survey results indicated that four labs used the same commercially available CLL FISH panel, and one used a combination of probes from the same vendor plus several home-brew probes. Each lab scored between 100 and 200 nuclei per hybridization site, and each independently set normal cutoff values. The FISH panel included probes to detect 11q, 13q, and 17p deletions, trisomy 12, and IGH gene rearrangement. One lab included probes to detect 6q deletion. In the first pilot study each lab used their hybridization methods, probe sets, and scoring criteria. Differences among labs were observed due to variations in probe strategy, reporting of anomalies, and perhaps most important, scoring criteria. Probe strategy differences resulted in variable reporting of 11q- vs monosomy 11 and 12q duplication vs trisomy 12. Some participants reported 13q-x1 and 13q-x2 as subclones and some reported only 13q-. One lab reported an IGH rearrangement whereas the others scored IGH as normal. In the second pilot study each lab used the same methods and probe sets to facilitate comparison of scoring by the technologists. All labs correctly identified the abnormalities, and there were no false positive results. Minor scoring differences were attributed to variation in scoring criteria or inexperience with an unfamiliar FISH probe strategy. The proficiency test that followed the workshop demonstrated 100% concordance in identification of abnormalities. Inter-lab scoring was much improved compared to the first pilot study. The only exceptions were a 13q- range of 72–90% in one case, and a 17p- range of 38–67% in another case. Conclusion: The pilot studies identified a need to develop common scoring criteria. The subsequent workshop and proficiency test demonstrated that the collaborative effort resulted in more standardized scoring among the CRC laboratories. Our collaborative study emphasizes the need to establish rigorous standards and guidelines for FISH procedures and scoring criteria. Standardization of FISH methods among participating laboratories will enhance the confidence in FISH studies for both clinical applications and cooperative intergroup clinical research.

Abstract Background: Chronic lymphocytic leukemia (CLL) patients exhibit variable times from diagnosis to the need to initiate therapy. Previous studies have demonstrated that the rates of CLL cell proliferation (birth) and elimination (death plus recirculation to solid tissues) could be estimated using the incorporation of deuterium (2H), taken in the form of heavy water (2H2O), into the DNA of dividing cells. In a cross-sectional study of patients with early and late stage CLL, birth rates above 0.35% per day were associated with more aggressive disease. The NIH-sponsored CLL Research Consortium (CRC) conducted a prospective study on patients with early stage disease to assess the relationship between CLL-cell birth rate and the length of time to initiation of initial therapy. Methods: Eligible patients had untreated early stage (Rai 0, 1 or 2) disease, and were no more than 3 years from diagnosis. Additional clinical parameters included age at diagnosis, gender, mutational status of the immunoglobulin heavy chain variable region (IGHV), 70-kD zeta-associated protein (ZAP-70) (binary split at 20%) and CD38 (binary split at 30%) expression, and FISH cytogenetics by the Dohner hierarchy. Heavy water was administered daily for 6 weeks, and peripheral blood was obtained for kinetic measurements at the end of weeks 3, 6, 9, 12, and 16. CLL birth rates for blood samples were measured at the same facility (KineMed, Inc, Emeryville, CA) by quantifying deuterium incorporation into the deoxyribose moiety of DNA of tumor cells, using isotope ratio mass spectrometry (IRMS). Subjects were followed for time to administration of therapy; subjects still without treatment at time of analysis were censored, as were subjects who exited the study to receive treatment outside of the established criteria. To assess the impact of birth rate and other factors on time to first therapy, Kaplan-Meier curves were compared using the logrank test for univariable analyses; stepwise Cox proportional hazards regression models were used to build multivariable models. Results: Between July 2005 and February 2009, 119 subjects were enrolled through the CRC. 107 subjects were eligible. For 10 eligible patients, exit from the study prior to completion of protocol-mandated heavy water consumption (n=5) or technical issues (n=5) made it impossible to obtain estimates of birth rate. The 97 eligible subjects for whom birth rates were available form the basis of this report. 60% of subjects were male; median age 57 years (range 40-85). Median birth rate was 0.32%/day (range 0.07-1.31%/day). 43 subjects (44%) had birth rates higher than the previously reported threshold of 0.35%/day. With a median follow up of 4 years, 33 eligible subjects (34%) required treatment. IGHV status (31 subjects unmutated), elevated ZAP-70 (31 subjects), elevated CD38 (21 subjects), and hierarchical categorization of FISH anomalies (4 del(17p), 5 del(11q), 8 tri(12), 50 del(13q)) were examined for association with differential time to first therapy in univariable analyses. All were associated with earlier need for therapy (p <0.001) except for genomic aberrations defined by FISH (p = 0.96). Birth rate > 0.35%/day was also significantly associated with shorter time to first therapy (p < 0.001). In multivariable modeling, only birth rate and IGHV status met the criteria for inclusion (Wald p-value < 0.05). Hazard ratios were 3.51 (p = 0.002) for birth rate above 0.35%/day and 5.0 for unmutated IGHV status (p < 0.001). The association between elevated birth rate and shorter time to first treatment was observed within subjects with both unmutated and mutated IGHV (see Figure 1). Conclusion: An increased birth rate of CLL cells early in the disease course is a strong predictor of an earlier need for treatment in univariable analysis, as are unmutated IGHV, elevated ZAP-70 expression and elevated CD38 expression. However, only unmutated IGHV and an increased birth rate contribute significantly to the multivariable model. This adds a direct measure of B-cell kinetics to the array of biomarkers available to subjects with CLL. Figure 1 Time to treatment by birth rate and IGHV status Figure 1. Time to treatment by birth rate and IGHV status Disclosures Murphy: KineMed, Inc: Equity Ownership. Emson:KineMed, Inc.: Employment, Equity Ownership. Li:KineMed, Inc.: Employment, Equity Ownership. McConnel:KineMed, Inc.: Equity Ownership. Turner:KineMed, Inc.: Employment, Equity Ownership. Busch:KineMed, Inc.: Equity Ownership. Hellerstein:KineMed Inc: Consultancy, Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Chiorazzi:KineMed, Inc.: Stock options Other.

Abstract Abstract 3865 ZAP-70 expression is a prognostic marker differentiating chronic lymphocytic leukemia (CLL) patients with indolent disease from those rapidly progressing after diagnosis and requiring treatment. We previously demonstrated in four independent clinical cohorts that DNA methylation at a single CpG dinucleotide in the ZAP-70 promoter region impacts on ZAP-70 transcriptional regulation and is prognostic in CLL (Claus et al. J Clin Oncol. 2012;30(20):2483–91). Here, we confirm and extend our previous findings by investigating the significance of ZAP-70 methylation relative to established prognostic biomarkers in CLL: IGHV mutation status or expression of ZAP-70 protein or CD38. DNA methylation analysis of the ZAP-70 core promoter region was conducted in mononuclear cells of 295 untreated CLL patients, previously reported by the CRC (Rassenti et al. Blood 2008;112:1923–30) using MALDI-TOF mass spectrometry (MassARRAY, Sequenom). The 295 patients had a median age of 55 years (range 26–82), 69% were male, and 46% were Rai stage 0, 47% stage I/II, and 7% stage III/IV at diagnosis. ZAP-70 protein and CD38 expression were measured by four-color flow cytometry and IGHV mutational status was assessed, as previously described. By hierarchical clustering, the previously identified single CpG dinucleotide (“CpG unit 1”, position +223 relative to the transcription start) separated patients with high methylation levels across the entire region from those with lower methylation levels at this specific site. With a median follow-up of 3.9 years in 50 patients who had not started treatment and 5.6 years among those still alive (n=196), patients with lower methylation levels at CpG unit 1 had shortened time to first treatment (TTT) and overall survival (OS) (both p<0.0001), confirming the prognostic relevance of this site. In our previous study, an optimal cut-off for CpG unit 1 methylation across four data sets was between 10% and 20%. In this cohort, the optimal cut-off across the two endpoints was between 15% and 25%. A natural gap in CpG unit 1 methylation levels occurred between 20% and 25%, adding potential biological significance, as lower values may represent patient cell samples in which both alleles are unmethylated. Applying a 20% cut-off, TTT and OS were significantly different for those with lower and higher methylation levels (both p<0.0001). The 5-year TTT estimates were 22% (95 % CI: 0.16–0.28) and 64% (95% CI: 0.52–0.74), respectively, for patients with low versus high methylation levels; 5-year OS estimates were 80% (95% CI: 0.73–0.85) and 90% (95% CI: 0.81–0.95). Low ZAP-70 methylation was significantly associated with CLL-cell expression of ZAP-70, CD38, or unmutated IGHV status (each p<0.0001). In a model of TTT, expression of ZAP-70 modified the strong effect of ZAP-70 methylation. In patients with CLL cells lacking ZAP-70 expression, high methylation was protective (hazard ratio [HR]=0.37, 95% CI: 0.23–0.58). In contrast, methylation had no significant effect in ZAP-70+ CLL (HR=1.47, 95% CI: 0.81–2.68); TTT was short regardless of methylation levels (Figure 1). IGHV mutation status and expression of CD38 did not provide significant additional prognostic information. The effect modification described for TTT was not observed for OS (p=0.57). Here, ZAP-70 methylation was the strongest risk factor (hazard ratio=0.32, 95% CI: 0.19–0.54; p<0.0001), and expression of ZAP-70, CD38 or unmutated IGHV did not significantly improve the ability to explain differences in OS. Hence, the prognostic value of ZAP-70 CpG unit 1 methylation was confirmed in a large patient cohort with extensive follow-up. We defined a clinically applicable threshold for ZAP-70 methylation assessment and determined its relative value to current prognostic markers in CLL. ZAP-70 methylation predicted longer TTT among patients with CLL cells lacking ZAP-70 expression, but not among those with ZAP-70+ CLL cells, although this could reflect sampling bias due to the small number of patients (n=16) in our cohort with both high methylation and expression of ZAP-70. Lastly, methylation was the strongest risk factor for OS, and neither IGHV mutation status nor expression of ZAP-70 or CD38 significantly improved the ability to predict prognosis. In conclusion, ZAP-70 DNA methylation represents a clinically valuable biomarker for predicting TTT and OS in previously untreated patients with CLL. Disclosures: Gribben: Gilead: Honoraria; Mundipharma: Honoraria; GSK: Honoraria; Pharmacyclics: Honoraria; Roche: Honoraria; Celgene: Honoraria. Kay:Celgene: Research Funding.

Abstract Abstract 1614 Poster Board I-640 Background Cytogenetic abnormalities in B-cell CLL are important prognostic indicators for predicting disease progression and treatment response. Until recently, only interphase cytogenetics has been readily applicable to clinical use in CLL due to the inability of traditional mitogens to promote effective metaphase cytogenetic identification. Recently, cytokine or CpG oligonucleotide stimulation has been utilized to promote efficient metaphase analysis. One concern with this approach is the actual clonality and reproducibility of such clones when examined by different cytogenetic laboratories. The CLL Research Consortium (CRC) conducted a prospective trial to test (1) whether CpG would enhance detection of abnormal clones and (2) whether the CRC cytogenetic laboratories would achieve similar results when testing the same patient samples. Methods Initially, one laboratory compared stimulation of CLL cells using CpG versus pokeweed mitogen (PWM) + 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in the same samples. To test the reproducibility of CpG stimulation, fresh blood samples from 1 normal control and 12 CLL patients were collected at one site and distributed (blinded to phenotype and prior cytogenetic results) to 5 CRC cytogenetic laboratories where they were cultured for 3 days using CpG stimulation, harvested, banded and analyzed utilizing standard laboratory procedures. When possible, each laboratory analyzed 20 metaphases per case. Interphase FISH analysis for CLL (including probes for chromosomes 6q, 11q, 12, 13q, 17p, and IGH/CCND1) was also done on each sample. Results In the PWM+TPA versus CpG comparison, more cases were found to have clonal abnormalities with CpG stimulation (147 of 229, 64%) than with PWM+TPA (110 of 229, 48%; P=0.0005). All clonal abnormalities detected in the PWM+TPA cultures were also observed in the CpG cultures. In the 5-laboratory CpG comparison, the results were compiled and compared to the concurrent FISH results. The CpG karyotypes were concordant with the FISH results. The control case had a normal CpG-stimulated karyotype in all 5 laboratories. Three cases exhibited a complex karyotype; one of these also exhibited 11q-, one had 17p-, and one had neither. The cytogenetic descriptions varied modestly among labs, but all identified the complex clones. Every case including the control exhibited some nonclonal abnormal cells, but no pattern was detected among the 5 labs. When an abnormal clone was found by only 1 or 2 labs, it was present in only a very small number of cells. A small 13q- clone was observed in 2 cases in 1 and 2 labs (3 of 20 and 5 of 50 cells, respectively), and was confirmed by interphase FISH. A single lab found 2 of 30 cells with a t(12;15) in one case. Conclusions Abnormal clones in CLL are more readily detected with CpG stimulation than with traditional B-cell mitogens. The clonal abnormalities revealed by CpG stimulation are consistent with the “gold standard” interphase FISH results, and are reproducible among different cytogenetic laboratories. We have no evidence that CpG oligonucleotides create new clonal B-cell populations in vitro during 3 days of cell culture. CpG stimulation in vitro reveals clonal cytogenetic abnormalities and complexity in CLL that should be evaluated as potential independent prognostic parameters. Disclosures Kay: Biogenc-Idec, Celgene, Genentech, genmab: Membership on an entity's Board of Directors or advisory committees; Genentech, Celgene, Hospira, Polyphenon Pharma, Sanofi-Aventis: Research Funding.

SummaryThis study revisited the Dohner prognostic hierarchy in a cohort of 1585 well‐documented patients with chronic lymphocytic leukaemia. The duration of both time to first treatment (TTFT) and overall survival (OS) were significantly longer than observed previously, and this is at least partly due to improved therapeutic options. Deletion 13q remains the most favourable prognostic group with median TTFT and OS from fluorescence in situ hybridization (FISH) testing of 72 months and >12 years, respectively. Deletion 11q had the poorest median TTFT (22 months) and 17p deletion the poorest median OS (5 years). The percentages of abnormal nuclei were significantly associated with differential TTFT for the trisomy 12, 13q and 17p deletion cohorts but not for the 11q deletion cohort. From the date of the first FISH study, patients with >85% 13q deletion nuclei had a notably shorter TTFT (24 months). Patients with ≤20% 17p deletion nuclei had longer median TTFT and OS from the date of the first FISH study (44 months and 11 years), and were more likely to be IGHV mutated.

Key Points Methylation analysis at ZAP-70 CpG+223 in CLL provides superior prognostic information vs IGHV status or CD38 or ZAP-70 expression. A pyrosequencing method for the feasible assessment of CpG+223 methylation in CLL samples is provided.

AbstractLeukemia-cell expression of ZAP-70, CD38, or unmutated immunoglobulin heavy chain variable region genes (U-IGHV) each is associated with aggressive disease in patients with chronic lymphocytic leukemia (CLL). To assess the relative strength of each marker, we defined thresholds for designating a case as positive for CD38 or ZAP-70 in a test cohort of 307 patients and used these data-defined criteria to stratify patients in an independent cohort of 705 patients. Multivariable analysis revealed that ZAP-70 was the strongest risk factor. Knowledge of the IGHV mutation status or CD38 did not improve our ability to predict the time to first treatment except for ZAP-70–negative cases, which could be segregated into 2 groups of intermediate-risk or low-risk disease based on whether they expressed unmutated or mutated IGHV. ZAP-70 maintained its high relative prognostic value for the subset of patients with early-stage, asymptomatic disease, including patients evaluated within 1 year of diagnosis. Although it is premature to recommend therapy based on these risk factors, patients with ZAP-70–positive CLL cells should be monitored closely for disease progression as they have a median time from diagnosis to requiring initial therapy by standard criteria of approximately 3 years.

AbstractWe examined the chronic lymphocytic leukemia (CLL) cells of 2457 patients evaluated by the CLL Research Consortium (CRC) and found that 63 (2.6%) expressed immunoglobulin (Ig) encoded by the Ig heavy-chain-variable-region gene (IGHV), IGHV3-21. We identified the amino acid sequence DANGMDV (motif-1) or DPSFYSSSWTLFDY (motif-2) in the Ig heavy-chain (IgH) third complementarity-determining region (HCDR3) of IgH, respectively, used by 25 or 3 cases. The IgH with HCDR3 motif-1 or motif-2, respectively, was paired with Ig light chains (IgL) encoded by IGLV3-21 or IGKV3-20, suggesting that these Ig had been selected for binding to conventional antigen(s). Cases that had HCDR3 motif-1 had a median time from diagnosis to initial therapy comparable with that of cases without a defined HCDR3 motif, as did cases that used mutated IGHV3-21 (n = 27) versus unmutated IGHV3-21 (n = 30). Of 7 examined cases that used Ig encoded by IGHV3-21/IGLV3-21, we found that 5 had a functionally rearranged IGKV allele that apparently had incurred antigendriven somatic mutations and subsequent rearrangement with KDE. This study reveals that CLL cells expressing IGHV3-21/IGLV3-21 most likely were derived from B cells that had experienced somatic mutation and germinal-center maturation in an apparent antigen-driven immune response before undergoing Ig-receptor editing and after germinal-center leukemogenic selection.