Jelinek, Diane F.

Abstract Myeloid cell factor-1 (Mcl-1) is an anti-apoptotic member of the Bcl-2 protein family that associates with tumor cell survival and drug resistance in chronic lymphocytic leukemia (CLL). Increased Mcl-1 expression is associated with failure to achieve remission after chemotherapy with fludarabine and chlorambucil in CLL patients. However, the influence of Mcl-1 expression has not been examined in CLL trials using treatment regimens that contain rituximab, which has shown substantially improved outcomes for a large subset of patients and have become a mainstay in the therapy of newly diagnosed CLL. We previously reported that combination chemoimmunotherapy with pentostatin, cyclophosphamide, and rituximab (PCR) has significant clinical activity with low accompanying toxicity in previously untreated CLL patients, and is especially well tolerated in older patients in whom the use of fludarabine may be associated with prohibitive toxicities. As part of this study, we prospectively investigated association of Mcl-1 protein expression with response and progression-free survival. Eligible patients received a regimen consisting of pentostatin (2 mg/m2), cyclophosphamide (600 mg/ m2), and rituximab (375 mg/m2) given intravenously on day 1 of a 21-day cycle for a maximum of 6 cycles. Responses were assessed according to NCI 1996 criteria and included bone marrow evaluation and two-color flow cytometry two months after completion of therapy. Flow cytometry-negative status was defined as less than or equal to 1% CD5+/CD19+ cells. Of the 64 patients evaluated in this trial, clinical responses were seen in 58 (91%), with 26 (41%) complete responses (CR), 14 (22%) nodular partial responses (nPR), and 18 (28%) partial responses (PR). Lysates from peripheral blood cells obtained pre-treatment were analyzed for Mcl-1 expression by immunoblot. Mcl-1 as a continuous variable was not found to be associated with other commonly described risk factors. However, Recursive Partitioning Analysis (RPA) was devised employing Mcl-1 expression as a continuous variable, which revealed an optimal cut point of 0.85. At this cutoff, flow cytometry-negative status was significantly different between the two groups (p=0.01) and median PFS was significantly higher (p=0.02) in patients with Mcl-1 levels of <0.85 (50.8 vs. 18.7 months). No difference by Mcl-1 expression was noted in other pre-treatment or response parameters. Our data describes the first prospective validation of Mcl-1 over-expression adversely influencing both the likelihood of attaining a flow cytometry-negative complete remission and extended progression free survival. Mcl-1 expression was also independent of other risk factors, indicating additional benefit for this measure in assessing patients. Mcl-1 expression may therefore predict poor response to chemoimmunotherapy, and these findings advocate pursuing therapeutic agents targeting this important anti-apoptotic protein.

Abstract Throughout differentiation, mature B cells express distinct combinations of the BAFF and APRIL receptors, BAFF-R, TACI, and BCMA. The patterns of B lineage cell receptor expression reflect their stage of differentiation and impart the ability to respond to ligands, in some cases delivering a powerful anti-apoptotic signal. B cell malignancies arise from each stage of differentiation, typically exhibit the patterns of receptor expression that reflect their cell of origin, and have been shown to exploit the generally anti-apoptotic effects of BAFF and/or APRIL. For example, there is evidence for a role for BAFF in mature B cell cancers, including B cell chronic lymphocytic leukemia (B-CLL). As the majority of circulating CLL B cells are quiescent cells, prolonged survival is a significant hallmark, a trait that signals through BAFF-R could initiate or reinforce. Therapeutic strategies designed to interrupt this pro-survival pathway have thus far primarily focused on blocking ligand binding. Therapeutic modalities impacting receptor expression may be similarly effective. However, despite the apparent precise activation stage-dependent orchestration of B cell BAFF-R, TACI, and BCMA expression, the genetic mechanisms regulating expression of the three receptors remain undefined, and the question of whether each receptor governs expression of the other two remains unanswered. In agreement with previous studies in our own lab and others, analyses of the receptor profiles of CLL B cells continue to show BAFF-R surface expression, albeit at lower levels than seen on normal peripheral B cells, and the curious variable presence of BCMA and TACI. Similarly, multiple myeloma (MM) plasma cells (PCs), like normal PCs, uniformly lack BAFF-R expression, express BCMA, and variably express TACI. Our current study explores the mechanisms of receptor regulation in B cells, with an emphasis on BAFF-R, the receptor that is most consistently expressed on the CLL B cell population and that has the most clearly defined survival function. We began by analyzing the BAFF-R gene’s genomic context. We identified a possible regulatory element 2 kb upstream of the first exon with significant homology across seven mammalian species that overlapped a cluster of B cell lineage transcription factor binding sites, and, thus, we called the 2.5 kb directly upstream of the gene the putative BAFF-R promoter. We cloned the region and created promoter-reporter vectors in which the full-length promoter and 0.5 kb 5’ truncations thereof drive firefly luciferase production. While studies of primary B cells continue, studies with malignant B cell lines suggest that we have successfully cloned a powerful positive regulatory region. Specifically, B cell lines that express surface BAFF-R show positive inductions of firefly to control renilla luciferase activity in all of the promoter constructs over the empty construct with the greatest promoter activity in the longest constructs: 6-, 18-, and 3-fold inductions with the 2.5 kb promoter in RAJI, Loukes, and MEC-1 cells, respectively. To further test the promoter specificity, we transfected malignant PC lines, ALMC-1, ALMC-2, and KAS-6/1, which are negative by RT-PCR and surface staining for BAFF-R. These lines showed little promoter activity over baseline, with fold inductions between 0.5 and 2.5 for all of the promoter constructs. These results suggest that the MM lines no longer express the transcription factors required to drive BAFF-R expression and underscore our conclusion that we have identified the BAFF-R promoter. At the same time, investigations into epigenetic modification may reveal a crucial level of control. The transcriptional start site of the BAFF-R gene falls within a region of high CG content, and may be a possible CpG island. Upon treatment with the methyltransferase inhibitor, 5-azacytidine, primary blood B cells and MM cells showed no change in receptor expression. However, in CLL B cells, treatment of cultured cells caused a slight (9%) decrease in BAFF-R expression and prevented TACI upregulation in cells stimulated with CpG (a 76% increase fell to 36%). This evidence suggests that methylation indirectly suppresses expression of BAFF-R and TACI. It is essential to understand the regulation of survival receptors critical to normal B lineage cell survival, which may also be crucial for their malignant counterparts, in order to target those mechanisms as therapy.

Abstract BACKGROUND: The diagnosis of monoclonal B-cell lymphocytosis (MBL) is used to characterize patients who have a circulating population of clonal B-cells, a total B-cell count of <5 x 109/L, and no other features of another B-cell lymphoproliferative disorder. In most patients the immunophenotype is similar to that of chronic lymphocytic leukemia with co-expression of CD19 and CD5. The natural history of CLL-phenotype MBL is unclear. We used the Mayo Clinic hematopathology database to identify patients with CLL-phenotype MBL and abstracted clinical information on natural history and prognostic parameters from clinical and research records. METHODS: Using hematopathology records, we identified a cohort of 1820 patients seen at Mayo Clinic between August 1998 and May 2006 who underwent investigation using peripheral blood flow cytometry and who were found to have a clonal B-cell population of CLL phenotype. After elimination of patients with advanced stage (Rai I-IV), previously treated CLL, and individuals with an established diagnosis of CLL/MBL >1 year prior to flow, 636 unique patients with isolated lymphocytosis were identified. Based on our prior analysis (Leukemia Research 32:1458) demonstrating that nearly all patients with an ALC >10x109/L have a B-cell count >5x109/L, we focused the remaining analysis on the 405/636 patients who had an ALC <10x109/L and the necessary raw data from flow cytometry analysis to determine the B-cell count. RESULTS: Among the 405 individuals with an ALC <10x109/L, 306 (76%) had a B-cell count <5x109/L at the time of flow and met the current criteria for the diagnosis of MBL (BJH 130:325). Median age at the time of MBL diagnosis was 70 years (range 34 – 93). A slight male preponderance was observed (59% male). B-cell counts ranged from 0.02 to 4.99x109/L and ALC ranged from 0.3–9.6 x109/L. CD38 status was available for 268 (88%) MBL patients of whom 20% were CD38 positive using the 30% threshold. Cytogenetic analysis by fluorescent in situ hybridization (FISH) was available in 130 (42%) MBL patients. Using the hierarchical classification system of Dohner and colleagues, 57 (44%) were 13q-, 23 (18%) were trisomy 12, 5 (4%) were 11q-, 4 (3%) were 17p-, and 39 (30%) had no defect detected. ZAP-70 status was available for 77 (25%) patients of whom 13% were ZAP-70+ positive. Patients underwent sequential monitoring with a median follow-up of 1.7 yrs (range 0–8.1 yrs). Time from diagnosis to treatment for patients meeting criteria for MBL (n=306) as compared to Rai stage 0 CLL patients with B-cell counts between 5.0 and 10.0 x109/L (n=99) was not significantly different and is shown in Figure 1 (p=0.87). For individuals with MBL, survival free of treatment was 98% (95%CI: 96–100%) at 1 year, 93% (95%CI: 89–98%) at 2 years, and 77% (95%CI: 67–89%) at 5 years. While gender (p=0.10), and B-cell count as a continuous variable (p=0.15) were not found to be associated with time to treatment (TTT) among MBL patients, age (p=0.02, HR=0.94, 95% CI: 0.89–0.99) and CD38 status (p<0.02, HR: 3.3, 95% CI: 1.2–9.2) did show a relationship with TTT. CONCLUSIONS: Although we observed a low rate of progression among individuals meeting criteria for MBL, TFS was similar to individuals meeting current criteria for Rai stage 0 CLL who had B-cell counts between 5.0 – 10.0 x109/L . Among individuals meeting criteria for MBL, younger patients and those who were CD38 positive had a shorter time to treatment. Additional studies are needed to determine what B-cell count or other characteristics should be used to distinguish between MBL and Rai stage 0 CLL. FIGURE: FIGURE:.

Abstract Background: This is an initial report of a correlative laboratory study of an ECOG clinical trial, E2903, to investigate an array of prognostic factors that are potentially associated with the clinical outcome in previously treated, high risk Chronic Lymphocytic Leukemia (CLL) patients. The ultimate goal of this study is to develop a prognostic model for this group of patients. Method: We have previously reported (ASH, 2007) on initial clinical and toxicity results using a combination of PCR followed by Campath. To date we have clinical response data on 37 patients and have conducted correlative prognostic factor analysis on these patients at entry to the study. The prognostic parameters assessed were fluorescence interphase hybridization (FISH) panel, CD38, ZAP-70 and IGVH (mutated vs. unmutated) status and plasma levels of pro- and anti-angiogenic cytokines. In addition, features such as clinical stage, age, sex and laboratory parameters including total white blood count, absolute lymphocyte count (ALC) and beta 2 microglobulin (b2m) were studied as predictors of response to PCR. Results: As of July 2008, the response data for the first 41 (the accrual goal is 110) patients who started the induction treatment are available. Of these 41, 3 patients are ineligible and one patient had no response data. The median age was 63 (range 51–76) with 29 males and 8 females, median b2m was 4 (range 2–28), 11 (31%) were Rai stage 0–2, and 26 (69%) were Rai 3–4. The median number of prior treatments was 2 (range 1–5); 15 of 23 (65%) patients tested for IGVH were unmutated, while on FISH analysis 4 had del 6q, 8 had del 11q, 4 had del 17p and 30 patients had complex FISH defects (>1 defect). Despite the prevalence of high risk features in this cohort of patients, 17 out of 37 responded (best response=partial response), 18 were stable and 2 had progressive disease with an overall response rate of 46%. Prognostic parameters most strongly associated with a clinical response included CD38 negative (p=0.008), ZAP-70 negative status (p=0.01) and mutated status (p=0.03). Responses were independent of age, sex, b2m, ALC, number of prior therapy or FISH defects. Responders showed a prolonged progression-free survival (PFS) compared to the PFS of non-responders (i.e., 2-yr PFS 29% vs. 0%, respectively, p<0.0001). Prognostic parameters most strongly associated with PFS included being both ZAP-70 negative (p=0.0009) and CD38 negative (p=0.004). Also, ZAP-70 negative and CD38 negative status was a strong predictor of favorable PFS (p=0.002). Mutated status was borderline significant (p=0.07) in univariate analysis and there was no obvious correlation of baseline angiogenic cytokine plasma levels with PFS. These results also hold in a multivariable Cox model. In the Cox model, mutated status was significantly associated with PFS (HR=0.2, p=0.01). Conclusion: We believe that the PCR regimen is highly effective at inducing responses in previously treated relapsed or refractory CLL patients who carry high risk prognostic markers. Thus, while no CRs were seen all but 2 patients had a PR or were stable after 6 cycles of PCR. The prognostic parameters most strongly associated with predictors of clinical outcome appear to be ZAP-70, CD38 and mutation status. The ability to attain a response also appears to be important for achieving a prolonged PFS. In summary, we believe that the strong clinical activity of PCR in a high risk group of CLL patients provides more evidence for pursuing the regimen as a platform for other combinations. In addition, we have generated a first level prognostic model that will continue to be refined as we proceed to complete this trial.

Abstract BACKGROUND: Karyotype analysis of metaphase cells for discovering genome-wide cytogenetic abnormalities has played an important role in prognosis and counseling of patients with chronic lymphocytic leukemia (CLL). Due to the low proliferative rate of CLL B cells, karyotype analysis has been of limited clinical utility in this disease. Thus, fluorescence in situ hybridization (FISH) on interphase cells has replaced karyotype analysis for the assessment of recurrent genetic changes in CLL. Recently, immunostimulatory CpG-oligodeoxynucleotides (CpG) have been shown to induce primary CLL B cell proliferation via engagement of toll-like receptor 9 (TLR9), thereby rendering karyotype analysis feasible and providing for a useful and reliable method to discover new cytogenetic abnormalities in CLL B cells. However, we and others have shown that CpG stimulation of CLL and normal B cells also induces robust expression of activation induced cytidine deaminase (AID), a mutagenic enzyme that is linked to the development of cytogenetic abnormalities. It is therefore plausible that cytogenetic abnormalities observed following CpG stimulation of CLL B cells may not reflect de novo abnormalities but rather reflect CpG induced-AID mediated cytogenetic alterations. We began to address this possibility by assessing the effects of CpG stimulation on the karyotypes of normal blood B cells. HYPOTHESIS: Since CpG stimulation induces AID expression in CLL and normal B cells, we hypothesize that: robust B cell activation by CpG could result in cytogenetic abnormalities thereby contributing to lymphomagenesis; and if CpG induces cytogenetic abnormalities that are linked to disease initiation and/or progression, such information would be of great value in the interpretation of cytogenetic data obtained from CpG-stimulated CLL B cells. METHODS: We performed interphase FISH analysis on freshly isolated blood B cells, and metaphase karyotype analysis on CpG stimulated B cells from 17 healthy blood donors. Pure (>98%) B cells obtained by negative selection, were hybridized at isolation with a probe set to identify deletion 6q, 11q, 13q, and 17p, trisomy 12, and IGH gene rearrangements, and cells were also stimulated for 5 days with 10 μg/ml CpG (CpG 2006, synthesized in-house) plus IL-2 and IL-15 for metaphase analysis. At least 20 post-CpG metaphase spreads were analyzed for each sample and abnormalities were considered clonal using the accepted convention (gains or translocations are present in two or more cells and loss present in at least 3 cells). The expression of AID in the B cells pre- and post-CpG stimulation was assessed by RT-PCR. RESULTS: FISH analysis of freshly isolated B cells showed that all 17 subjects were normal. After CpG stimulation, all samples examined exhibited strong AID expression as revealed by RT-PCR. By karyotype analysis, none of the 17 CpG stimulated samples showed evidence of clonal abnormalities. However, one or more nonclonal chromosomal abnormalities were observed in 7 out of 17 (41.2%) samples. Among those 7 samples, 4 samples had 1 abnormal metaphase out of a minimum of 20 examined while the other 3 samples exhibited two or more cells, each with distinct abnormalities. Some of those nonclonal abnormalities have also been observed in CLL (i.e., trisomy 3, trisomy 12 and 14q32 rearrangements). This is a much higher incidence of nonclonal abnormalities than has been seen with peripheral blood cells cultured by other methods. CONCLUSION: Our data have significance for the biology of CLL and for clinical practice. First, our data suggest that signaling through TLR9, and perhaps other receptors that likewise induce robust B cell AID expression, may represent a natural mechanism by which B lineage cells acquire chromosomal abnormalities during normal immune responses that may predispose toward neoplastic transformation. Second, given that none of the CpG-induced metaphases in normal B cells resulted in clonal abnormalities in the 5 day timeframe, our data also validate the clinical utility of CpG as a valuable tool for the cytogenetic analysis of CLL B cells since only clonal abnormalities are currently scored. However, it remains possible that non-clonal abnormalities seen in CpG-stimulated CLL B cells may be relevant to the disease process if future work shows that CpG stimulation uncovers recurring non-clonal defects of chromosomes/genes associated with tumorigenic events.

Abstract Background: Normal and tumor stem cells are characterized by high activity of multidrug resistance (MDR) transporters. One of these, ABCG2 (ATP-binding cassette, sub-family G member 2 protein), is an ATP dependent transporter and putative stem cell marker responsible for verapamil sensitive Hoechst efflux. While ABCG2 is known to be expressed in normal and leukemic stem cells, as well as a small population of normal lymphocytes and some B-cell malignancies, its expression in chronic lymphocytic leukemia (CLL) is unknown. It has been postulated that leukemic stem cells due to their quiescent nature and expression of MDR transporters represent a population resistant to therapy and that this residual population is critical for tumor persistence and recurrence. Hypothesis: We hypothesized that ABCG2 is expressed in a small percentage of primary CLL B cells; gene expression profiles of ABCG2 positive versus ABCG2 negative CLL B cells differ in respect to expression of self renewal and lymphoid development genes; the frequency of ABCG2+ CLL B cells increases after treatment in patients responding to therapy. Methods: We analyzed ABCG2 expression by primary CD5+, CD19+ CLL-B cells from untreated CLL patients of all Rai stages by flow cytometry. In a subset of patients we used fluorescence activated cell sorting (FACS) to sort CD19+, CD5+ ABCG2+ and CD19+, CD5+ ABCG2- cells. Gene expression profiling was then performed using the U133 plus 2.0 Affymetrix microarray platform. In a separate cohort of patients treated in a clinical trial of pentostatin, cyclophosphamide and rituximab (PCR), the percentage of ABCG2+, CD19+, CD5+, CD79b dim cells at baseline and then two months after completion of 6 cycles of PCR therapy where patients had minimal residual disease (MRD) was assessed and correlated with clinical response. Results: ABCG2+ CD19+, CD5+ detectable populations were seen in all 20 CLL assessed patients (median percentage 0.6%; range 0.08%–3.8%). There was no difference in percentage of ABCG2+ cells based on Rai stage, IGVH mutational status, Zap70 or CD38 expression. Preliminary analysis of the gene expression profiling of ABCG2 positive versus negative CLL B cells from four randomly selected patients revealed significantly higher expression of genes associated with self-renewal, cell cycle and early B-cell development including: cyclin-dependent kinase inhibitor 1C (CDKN1C, p=0.034), transcription factor 7-like 2 (TCF7L2, involved in WNT pathway regulation, p=0.016), beta-catenin (p=0.034) and pre-B-cell colony enhancing factor 1 (PBEF-1, p=0.037). Flow based assessment of the levels of ABCG2 positive populations at baseline and after therapy with PCR in patients with minimal residual disease showed a dramatic increase in frequency of ABCG2 positive CLL B cells. The percentage of ABCG2+ cells went from a median level of 0.19% (range 0.04%–0.19%) prior to therapy to a median level of 10.93% (range 0.15%–25.12%), p<0.001. In contrast two patients who did not reach MRD (partial responses by NCI-WG criteria) had no significant increase in percentage of ABCG2 positive cells (0.14%; 0.23% and 0.16%; 0.21% prior and after therapy, respectively, p=0.68). Conclusion: Our data indicate that ABCG2 positive CLL B-cells constitute 0.1–3.8% of circulating CLL B-cells in untreated patients. The frequency of ABCG2+ CLL B-cells appears to dramatically increase after therapy in the MRD state; this could be related to their relative resistance to therapy and/or a shift from extravascular compartments post therapy. Since ABCG2 positive CLL B-cells demonstrate expression of early B-cell development and self-renewal genes we believe that that this population could represent a putative self renewing CLL B-cell compartment. Further studies to characterize features of ABCG2 CLL-B –cells in relation to their capacity to be self renewing and resistance to therapy are warranted.

Abstract Within the past five years studies published from this laboratory and others have identified or confirmed CD38 as a marker for aggressive disease in B cell chronic lymphocytic leukemia (B-CLL). To learn more about the possible role of CD38 in this disease, we performed gene expression profiling (GEP; Affymetrix U133A platform) on primary leukemic B cells isolated from CD38 positive and negative patients. We and others have previously shown that the leukemic compartment within some patients consists of both CD38neg and CD38pos CLL B cells. To optimize identification of differentially expressed genes associated with CD38 expression or lack thereof, we restricted our gene profiling to patient cells that were unimodally negative for CD38 and those that expressed unimodally high levels of CD38. In both groups of patients, CD19 positive cells were purified using magnetic bead cell sorting on a Miltenyi AutoMacs prior to isolation of total RNA. To determine genes that appear to be differentially expressed in this set of experiments, we used a recently developed model-based algorithm that uses the normalized probe-level data as well as information about the underlying experimental design. Reassuringly, the gene expression profiles within the CD38pos versus the CD38neg cohort maintain congruency within each cohort when analyzing the gene expression data set as a whole, as well as within categories such as adhesion, signaling, and transcriptional molecules. Using this analytical approach, several genes emerged as interesting candidates for exploration into the nature of the CD38pos association with disease aggressiveness. Interestingly, although peripheral blood CLL B cells are overwhelmingly in the resting, G0, stage of the cell cycle, several cell cycle related genes were expressed at higher levels in CD38pos patient leukemic cells but not in CD38neg leukemic patients. Moreover, these genes encompass protein families that function at different stages throughout the cell cycle. These genes include: anaphase promoting complex subunit 5 (APC5); cell division cycle (cdc) family members; a checkpoint protein CHFR; the microtubule and actin associated protein, MACF1; the mitotic spindle checkpoint protein, MAD1L1; the DNA replication regulator, MCM7; STAG3, a meiotic regulator of chromosome segregation; and several activators of the ubiquitin pathway, including UBE2N, a known regulator of DNA repair enzymes (p-values of <0.01, <0.01, <0.01, 0.01, 0.02, <0.01, 0.01, and 0.01, respectively). We have begun to confirm these findings at the protein translation level. Through immunoblotting, preliminary data show that 3 out of 5 CD38pos and 0 out of 5 CD38neg patients’ leukemic cells express detectable levels of APC5, suggesting that CD38pos cells, or at least a subpopulation of cells, express APC5. Taken together, these gene and protein expression data suggest that at least a subpopulation of the leukemic cells from CD38pos CLL patients have more recently completed the cell cycle and maintain expression of specific cell cycle related genes. Alternatively, it is possible that this subpopulation is better prepared to re-enter the cell cycle if it encounters proliferative stimuli in other microenvironments.

Abstract BACKGROUND: The diagnosis of CLL among asymptomatic patients without lymphadenopathy or cytopenias has historically been based on documenting a characteristic lymphocyte clone and the presence of lymphocytosis. Currently, there are no data regarding what lymphocyte type (absolute lymphocyte count [ALC] or B-cell count) or threshold should be used for this diagnosis. We analyzed the relationship of these lymphocyte counts to clinical outcome in a cohort of 459 patients to determine whether the CLL diagnosis: should be based on ALC or B-cell count what lymphocyte threshold should be used for diagnosis whether any lymphocyte counts has independent prognostic value after accounting for molecular prognostic markers. METHODS: We used the Mayo Clinic CLL database to identify all Rai stage 0 patients diagnosed with CLL between 1/1/00 and 12/31/07 who were evaluated and had flow cytometry at Mayo within 12 months of diagnosis. All patients had lymphocytosis (ALC ≥5 x 109/L) and fulfilled the 1996 criteria for CLL. Raw data from the peripheral blood flow analysis was used in conjunction with blood counts to determine ALC and absolute B-cell count at diagnosis. Estimates of survival were calculated using the Kaplan-Meier method. RESULTS: To assess whether B-cell count or ALC more strongly related to clinical outcome, we evaluated the relationship of these variables with treatment free survival (TFS) and overall survival (OS; n=459). When treated as continuous variables (i.e. measuring risk of each 1.0 x 109/L increase in cell count), both ALC and B-cell count were related to TFS (hazard ratio [HR] ALC=1.02; p<0.0001; HR B-cell count=1.02; p<0.0001) and OS (HR ALC=1.02; p=0.04; HR B-cell count=1.02; p=0.02). Because B-cell count and ALC related to TFS and OS as a continuous variables, we next evaluated what threshold (nearest 1.0 x109/L) at diagnosis best related to an individual’s risk of requiring chemotherapeutic treatment and/or dying of CLL using the HR (log rank statistic) and c-statistic [c=1 indicates perfect discrimination between poor survivors and good survivors; c=0.5 equivalent to chance]. The B-cell threshold that best predicted OS was 11 x 109/L (HR=2.36, p=0.01; c=0.60). This threshold also predicted TFS (HR=3.02; p<0.0001; c=0.64). With respect to ALC, a threshold of 12 x 109/L was able to predict TFS (HR=2.28, p=0.003; c=0.62) but not OS (HR=1.62, p=0.12; c=0.56). The B-cell threshold used in the current diagnostic criteria (5 x 109/L) was able to predict TFS (HR=3.24, p<0.0001; c=0.63), but not OS (HR=1.64, p=0.13; c=0.55) Finally, we evaluated the ability of B-cell count to predict TFS independent of IGHV mutation status, ZAP-70 status, CD38 status, and FISH. Since not all patients had all prognostic tests performed, the predictive value of B-cell count (< or ≥11 x 109) independent of the other prognostic variable was assessed for each variable independently. B-cell count retained prognostic value independent of IGHV mutation status, ZAP-70 status, CD38 status, and FISH (all p≤0.001) [Table]. CONCLUSIONS: Although B-cell count and ALC have similar ability to predict TFS and OS as continuous variables, B-cell count may be a better predictor of TFS and OS when a defined lymphocyte threshold is used. These findings provide evidence to justify the recent proposal by Hallek et al (Blood 111:5446) to base the diagnosis of CLL on B-cell count rather than ALC. The results also provide justification for retaining the size of the B-cell count as part of the diagnostic criteria even in the era of molecular/biologic prognostic markers, but imply a threshold of 11 x 109 is the B-cell count that best predicts patient’s TFS and risk of death. Differentiating between CLL and MBL based on a patient’s likelihood of developing clinical symptoms and dying of disease could minimize unnecessary psychologic distress caused by labeling asymptomatic individuals at low risk for adverse clinical consequences as having leukemia. TABLE: TREATMENT FREE SURVIVAL HR p-value CD38 + 3.20 0.0002 B-cell ≥11 3.10 0.0001 ZAP + 8.33 < 0.0001 B-cell ≥11 6.86 < 0.0001 Unmutated 5.26 < 0.0001 B-cell ≥11 3.06 0.001 FISH (17p- or 11q-) 3.97 0.01 B-cell ≥11 3.67 < 0.0001

Abstract Motexafin gadolinium (MGd, Xcytrin®) is a tumor-selective redox mediator that oxidizes intracellular reducing metabolites and protein thiols, thereby generating reactive oxygen species (ROS) through a process known as redox cycling. B-cell chronic lymphocytic leukemia (CLL) has elevated levels of the antioxidant ascorbate, and is known to be sensitive to redox stress. Since MGd can generate ROS through oxidation of ascorbate, we reasoned that MGd would be cytotoxic to CLL cells. Mononuclear cells were isolated from the blood of CLL patients (n=15) characterized by Rai Stage, CD38, FISH and immunoglobulin heavy chain variable (Ig VH) mutational status. CLL cells were incubated in vitro over 2–5 days with MGd at concentrations ranging from 0–50 uM. Cytotoxicity was assessed by flow cytometry using annexin V binding/propidium iodide uptake. Accumulation of MGd in CLL cells was demonstrated by flow cytometry using drug fluorescence (>650 nm). MGd-induced cytotoxicity was found to be dose-dependent over a range of 2.5 to 50 uM in cells from 11 of 15 CLL patients. CLL cells from 11/15 patients treated with 50 uM MGd and 4/15 patients treated with 10 uM MGd had cytotoxicity levels at least 2 fold above baseline. MGd uptake was similar in sensitive and resistant CLL cells, implying that mechanisms other than uptake are responsible for the differential responses. CLL cells that were sensitive to MGd treatment showed an increase in caspase-3 activity and cleavage of the caspase substrate PARP was found by immunoblot suggesting that MGd induced apoptosis. The induction of apoptosis was found to be exclusive of Rai stage, CLL FISH defects, CD38 expression or Ig VH mutational status. Cells from 5 CLL patients were studied for drug synergy using seven concentrations of MGd (7.5 – 50 uM) and the active moiety F-ara-A of fludarabine (0.25 –2.0 uM). The cells were treated with each drug individually or both drugs for 48 hours prior to analysis for cytotoxicity. MGd was found to exhibit additive activity (N=4) or synergistic (N=1) effects on CLL B cytotoxicity when combined with fludarabine. Thus, our pre-clinical results reveal that MGd is cytotoxic to CLL cells in vitro through induction of apoptosis. Furthermore, MGd shows additive or synergistic activity when combined with fludarabine. These results support the evaluation of MGd in ongoing CLL clinical trials utilizing this agent alone or in combination with fludarabine.

Abstract Background: Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell proliferative disorder with a high risk of progression to symptomatic multiple myeloma. Identification of risk factors that predict progression of SMM to symptomatic MM could identify higher risk patients who might benefit from chemoprevention or more intensive surveillance. We hypothesized that increased monoclonal free kappa or lambda immunoglobulin light chains in smoldering myeloma (SMM), as detected by the serum free light chain (FLC) assay, indicates an increased the risk of progression to active myeloma. Methods: Of 276 pathologically confirmed SMM patients seen at the Mayo Clinic from 1970 to 1995, baseline serum samples obtained within 30 days of diagnosis were available in 273. Results: At a median follow-up of surviving patients of 12.4 years, transformation to active disease has occurred in 161 (59%) patients. An abnormal FLC ratio was present at baseline in 90% of patients. The best break-point for predicting risk of progression was a FLC ratio less than or equal to 0.125 or greater than or equal to 8 (hazard ratio, 2.3; 95% CI, 1.6–3.2) [Figure 1]. The extent of abnormality of FLC ratio was independent of SMM risk categories defined by number of plasma cells in the bone marrow and size of serum M-proteins (bone marrow plasma cells ≥ 10% and serum M protein ≥ 3 g/dL; bone marrow plasma cells ≥ 10% but serum M protein < 3 g/dL; and serum M protein ≥ 3 g/dL but bone marrow plasma cells < 10%). Incorporating the FLC ratio into the risk model, the division of patients into high-, intermediate-, and low-risk groups is 28, 42, and 30% with 5 year progression rates of 76, 51, and 25%, respectively [Figure 2]. Conclusions: The serum immunoglobulin FLC ratio is an important additional determinant of clinical outcome in patients with SMM. Figure Figure Figure Figure