Jelinek, Diane F.

Abstract Abstract 2917 Multiple myeloma (MM) is a cancer in the bone marrow (BM) characterized by the accumulation of transformed plasma cells (PCs). The pre-malignant form of the disease, monoclonal gammopathy of undetermined significance (MGUS), shares many of the genetic abnormalities found in MM, including chromosomal translocations, hyperdiploidy, and gene-specific mutations. Given this, we believe other factors within the tumor microenvironment must contribute to disease progression by influencing cell survival and/or proliferation. Eosinophils (Eos) are granulocytic leukocytes that are best known for their involvement in host immune defense and pathologic states such as allergy and asthma. Recently, they were also shown to play a role in the regulation of murine BM PC homeostasis via their secretion of IL-6 and APRIL. Murine BM PCs and Eos both express CXCR4 and are believed to home to CXCL12 expressing stromal cells (SCs) in the BM. The goal of this study, therefore, was to investigate whether Eos, or soluble mediators released by Eos, have biological activity on MM cells. Thus, it is possible that this type of innate immune cell may be present in the tumor microenvironment in MM patients to support disease progression. To our knowledge, a potential role for Eos in MM has not been previously studied. We began our studies by assessing whether Eos are co-localized with normal BM PCs and/or MM PCs. Immunofluorescence analysis of BM core biopsies from normal subjects revealed occasional colocalization of PCs with Eos. Similarly, MM biopsies showed regions of MM cell clusters with increased Eos density, suggesting possible biological interactions. However, we also observed regions of MM cell clusters that lack Eos, which could indicate the liberation of these transformed cells from the requirement of Eos for survival/proliferation. Next, using Eos isolated from human BM aspirates and a panel of disease-relevant human MM cell lines (HMCLs) extensively characterized in our laboratory, we aimed to verify that MM cells and Eos could both migrate toward the chemokine CXCL12. Our data showed that indeed the KAS-6/1, ANBL-6, DP-6, and KP-6 HMCLs and human BM Eos all migrated toward this chemokine. We then determined if Eos had biological activity towards MM cells as revealed by enhanced DNA synthesis. Consistent with our interpretation of the immunofluorescence stained sections, the proliferation of some, but not all, HMCLs was enhanced when cocultured with Eos isolated from either human BM or peripheral blood. To address whether contact between Eos and HMCLs was required for this phenomenon, we assessed HMCL proliferation upon treatment with Eos culture supernatant (SN). Our data suggest that the effect of Eos on the Eos-inducible HMCLs can be contact-independent as treatment of these HMCLs with Eos SN increased their proliferation. Similarly, proliferation of primary CD138+ MM cells was also enhanced when treated with Eos SN. Because BM PCs reside in niches that include support cells such as SCs and that proliferation of MM PCs is enhanced in the presence of SCs, we next questioned whether Eos can substitute for SCs in this niche or if Eos and SCs support PC survival/proliferation through different mechanisms. We observed that Eos and BM SCs together stimulated more HMCL proliferation than either cell type did alone, indicating the presence of non-redundant roles for the two cell types. Finally, we began to investigate the mechanism by which Eos enhance HMCL proliferation. In contrast to prior reports that murine Eos express IL-6, mRNA transcripts of IL-6, a known proliferation-inducing cytokine for MM cells, were not detected in human Eos. Moreover, analysis of the Eos SN showed an absence of IL-6. Neutralization of IL-6 in the HMCL-Eos coculture did not abolish the induced proliferation. Altogether, these data suggest that human Eos utilize a yet to be identified, IL-6-independent mechanism to support malignant PC proliferation. Taken together, our data show that Eos and MM cells can colocalize in the BM via their migration toward a common source of CXCL12, i.e. BM SCs, to create a niche that promotes tumor cell growth. Eos can enhance malignant PC proliferation via soluble products, although additional contact-dependent effects may exist as well and have not been explored. Additional studies are currently underway to further characterize the mechanism by which Eos may influence the biology of MM in the tumor microenvironment. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2901 Background: The median age at diagnosis of patients (pts) with chronic lymphocytic leukemia (CLL) is 72 years (yrs). According to the Surveillance and Epidemiology End Results (SEER) database, approximately 11% of all pts diagnosed with CLL in 2009 were <55 yrs. All previously reported series on the natural history of younger CLL pts are more than a decade old, and did not include information on contemporary prognostic parameters (such as immunoglobulin heavy chain gene mutation status [IGHV], genetic abnormalities by fluorescence in-situ hybridization [FISH], ZAP-70, etc). These reports also occurred prior to the introduction of modern treatment strategies (e.g. chemoimmunotherapy (CIT); reduced intensity allogenic stem cell transplant [SCT]), making their data on important clinical outcomes such as time to first treatment (TTT) and overall survival (OS) of uncertain relevance to younger pts in the modern era. Methods: We explored the natural history of younger pts with CLL using the Mayo Clinic Database. All pts ≤ 55 with pathologic diagnosis of CLL who were seen at the Mayo Clinic between January 1995 and April 2012 were included in this study. Baseline demographic and clinical characteristics, prognostic variables and administered treatments were abstracted from the medical records. Outcomes of pts in this cohort was compared to CLL pts >55 seen during the same time period. OS of pts ≤55 was also compared to the age- and sex- matched normal population of the state of Minnesota. The Mayo Clinic Institutional Review Board approved this study. Results: Collectively, 844 pts ≤ 55 yrs (median age, 48.7 yrs) with newly diagnosed CLL and seen within 1 year of diagnosis were included in this analysis. The characteristics of these pts were compared to 2324 newly diagnosed pts>55 yrs (median age, 68.4 yrs) seen during the same interval. When compared to pts>55, younger pts were more likely to present as intermediate Rai stage disease (p<0.0001), IGHV unmutated (p=0.001), and ZAP-70 positive (p=0.009). Younger pts were also more likely to have 1 or more first degree relatives with CLL (familial CLL) than older pts (10.9% vs. 8.5%; p=0.04). No significant differences were seen in the gender distribution, CD38 status, or FISH risk category. When pts ≤ 55 were further stratified by age, 204 (24%) were ≤45 yrs, 272 (32%) were 46–50 yrs, and 368 (44%) age 51–55 yrs at diagnosis. Similar to the comparison with the >55 year old group, pts ≤45 were more likely to present with intermediate Rai stage disease (61.7%) than those 46–50 yrs (52.5%), or 51–55 yrs (48.8%; p<0.01). Pts ≤45 were also more likely to be IGHV unmutated (p=0.034) and ZAP-70 positive; however, the ZAP-70 status was not significantly different (p=0.095). No difference in the prevalence of familial CLL was observed by the age stratifications of the ≤55 group. After a median follow-up of 5.5 yrs (range, 0–17 yrs), 426 (50%) pts ≤55 had received treatment for CLL and 192 (23%) pts had died. Pts ≤55 had a shorter TTT (4.0 yrs vs. 5.2 yrs; p=0.001) but longer OS (12.5 yrs vs. 9.5 yrs; p<0.0001) compared to pts >55 yrs. In contrast, no differences in TTT or OS were observed when the age ≤55 pts were sub-stratified into the ≤45, 46–50, and 51–55 age groups. A significantly higher proportion of pts≤55 received SCT than those >55 (7% vs. 1%; p<0.0001), with even further stratification of the ≤55 group (SCT age≤45: 13.7%; age 46–50: 5.1%; age 51–55: 3.5%; p<0.0001). As a group, CLL pts ≤55 have significantly shorter OS than the age- and sex-matched population (median CLL=12.5 yrs; median population=not reached; p<0.0001, Figure). However, pts≤55 who were Rai Stage 0 and had mutated IGHV had comparable survival to the general population (p=0.97). Similarly, pts≤55 who were Rai Stage 0 and had favorable FISH results (13q- or normal) had comparable survival to the general population (p=0.27). Conclusion: Our study is the first comprehensive analysis of younger CLL pts in the modern era. We found that younger pts are more likely to present with intermediate Rai stage disease, and have IGHV unmutated and ZAP-70 positive status. Consistent with these characteristics, younger pts experience shorter TTT. Although the OS of younger CLL pts is longer than those >55, their survival relative to the age- and sex-matched normal population is profoundly shortened even with the advent of CIT and SCT. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

Abstract Reliable model systems are critical for investigating the genetic and molecular drivers of disease pathogenesis. Although the number of cell line model systems for multiple myeloma is extensive, recent studies showed patient tumors and cell lines clustering separately based on gene expression profiles. Furthermore, the hyperdiploid karyotype, present in approximately 50% of myeloma patients, is also extremely underrepresented in established human myeloma cell lines (HMCLs): only one of 59 HMCLs contains this phenotype. These data suggests that the average HMCL does not accurately represent the average myeloma patient and questions the validity of using HMCLs as model systems. However, most HMCLs were established from patients with pleural effusions or plasma cell leukemia, which are highly progressed and rare forms of myeloma. To assess how cell lines correlate with patient material, we performed a copy number abnormality (CNA) comparison between four myeloma primary tumors and their corresponding HMCLs. Here, we show that established HMCLs maintain the majority of the CNAs, contain a ten-fold greater frequency of 7q gains compared to patients, and that KP-6 is the second hyperdiploid HMCL known to date. CNAs were identified using array comparative genomic hybridization (Agilent 244k) with data analyzed at a resolution of 26kb. On average 59% (46.7-77.3) of the CNAs were shared between the tumors and their cell lines, 17% (8.5-25.9) were unique to the patient samples, and 24% (13.6-36.6) were only detected in the HMCLs. To put these differences in context we also compared the diagnostic material from which JMW-1 was established with a progression sample collected 9 months later after 3 cycles of VAD followed by an autologous peripheral blood stem cell transplant. The patient diagnostic and relapse tumors showed 58% similarity based on CNAs while the diagnostic and relapse tumors contained 8% and 34% unique events respectively. These results indicate that established HMCLs are no more divergent from their primary cells as is the same patient's relapse material. Overall the HMCLs studied appear highly representative of the patient from which they were derived, with most differences attributed to an enrichment of subclonal populations present in the primary tumor admixture. Of particular interest, ubiquitous 7q gains were an unexpected unifying event across all patient tumors and their HMCLs. We then analyzed the 729 baseline myeloma tumors with copy number data from the MMRF CoMMpass study against our panel of 59 similarly characterized HMCLs. We observed that HMCLs contained a 10-fold increase in the occurrence of 7q gains with respect to non-hyperdiploid patients with 7q gains (35/59 in HMCLs and 19/344 in patients). Because 97% of HMCLs are non-hyperdiploid and 7q gains are extremely rare in this population, over-representation of 7q gains in cell lines suggests that this event may promote extra-medullary growth and the establishment of cell lines. Profiling of patient tumors for gains on 7q may therefore increase the probability of establishing a new HMCL and help expand our model systems for understanding this disease. Further studies are required to understand the potential biological significance of this event in vitro . We also identified the KP-6 cell line as a novel hyperdiploid HMCL established from an extramedullary site of an advanced hyperdiploid patient. The presence of trisomies for at least four of the odd-numbered chromosomes is characteristic of a hyperdiploid myeloma patient. From the patient's tumor, clear trisomies were observed on chromosomes 3, 7, 11, 15, 19, and 21 and the HMCL established from this hyperdiploid patient maintains full trisomies of chromosomes 15, 19, and 21, with partial p-arm trisomies on chromosomes 7, 11, and 17. Since this is only the second bona fied hyperdiploid myeloma cell line to date, KP-6 promises to play a major role in our ability to understand the pathogenesis and progression of this prominent patient population. Overall, our research indicates that, based on CNAs, HMCLs are as representative of the primary tumor as is the same patient's tumor at a later time point. Additionally, HMCLs contain a 10-fold overabundance of 7q gains. Finally, we showed that KP-6 is the second hyperdiploid HMCL known to date. Taken together, these results suggest that HMCLs are reliable model systems for investigating the underlying biology of multiple myeloma. Disclosures No relevant conflicts of interest to declare.

Abstract In chronic lymphocytic leukemia (CLL), the molecular features of the clonotypic B-cell receptor immunoglobulins (BcR IG) are set from the birth of the clone and in contrast to genetic aberrations, remain stable overtime, rendering the BcR IG a reference biomarker that is usually not significantly affected by clonal evolution. Approximately 30% of CLL cases carry quasi-identical BcR IGs and can be assigned to distinct stereotyped subsets. While preliminary evidence alludes to BcR IG stereotypy being relevant from a clinical viewpoint, this aspect has never been explored systematically or in a cohort of adequate size to enable meaningful conclusions. In order to assess the clinical implications of BcR IG stereotypy, we evaluated clinicobiological data from 8593 CLL patients, particularly focusing on 14 major stereotyped subsets of cases with unmutated (U-CLL) or mutated IGHV genes (M-CLL). The largest subset was #2 (n=254, 3%), within which 156 and 98 cases were M-CLL and U-CLL, respectively, followed by U-CLL subsets #1 (n=173, 2%) and #7 (n=123, 1.4%). Amongst M-CLL, the largest subsets were #4 (n=94, 1.1%) and #148 (n=92, 1%). Stereotyped subsets, even of the same mutational category i.e. U-CLL or M-CLL, exhibited significant clinicobiological differences regarding: age at diagnosis (median age ranging from 53-68 years, p<0.001); gender distribution (male/female ratios ranging from 0.85-4.4, p<0.001); the frequency of advanced stage disease (Binet C) at diagnosis (ranging from 9-21%, p<0.001); CD38 positivity (median percentage of positive cells ranging from 2-73%, p<0.05). Moving to cytogenetic findings, we detected subset-biased spectra of FISH-detected aberrations which can be summarized as follows: (i) isolated del(13q) varied from 10% in subset #8 (U-CLL), to 29% in subsets #59 (U-CLL) and #16 (M-CLL), and >75% in M-CLL subsets #77 and #148 (p<0.001); (ii) trisomy 12 was absent in subsets #31 (U-CLL) and #77 (M-CLL), in 20% of subset #201 (M-CLL) and, 60% in subset #8 (U-CLL) (p<0.001); (iii) del(11q) ranged from 69% in subset #31 (U-CLL) to 12% in subset #8 (U-CLL) and 0% in M-CLL subsets #16 and #201 (p<0.001); (iv) del(17p): absent from all M-CLL subsets except #148 (7.5%); absent from U-CLL subsets #5 and #59, and present in 19% and 17% of stereotyped subset #8 and #6 cases, respectively (p<0.05). We considered subset #2 separately since it included both M-CLL and U-CLL and identified a distinctive clinicobiological profile characterized by a constellation of features, including high incidence of Binet stage C disease (21%), CD38 positivity (41%) and certain cytogenetic abnormalities i.e. del(13q) (56%) and del(11q) (23%) and, in contrast, low frequency of del(17p) (4.5%). Notably, no differences were found between U-CLL versus M-CLL subset #2 cases regarding the incidence of these parameters. Survival analysis for time-to-first-treatment (TTFT) revealed that each stereotyped subset exhibited a distinct clinical course, different from that of other subsets even with similar IGHV gene mutational status and/or expressing the same IGHV gene. Interestingly, subsets #1 and #2 demonstrated a similar TTFT to that of del(17p) positive cases, while within subset #2 the clinical outcome was independent of IGHV mutational status. By integrating BcR IG stereotypy into the Döhner cytogenetic prognostication model, we found that subsets #1, #2 and #4, collectively accounting for ~7% of our series, and representing both U-CLL and M-CLL, constituted distinct clinical entities, with the latter exhibiting a particularly indolent disease even when compared to isolated del(13q) cases or cases with no cytogenetic aberrations. Finally, in multivariate analysis for TTFT, assignment to subset #2 emerged as a new independent unfavorable factor (p=0.002); furthermore, when restricting the analysis to Binet A cases, subset #2 exhibited the second highest hazard ratio after U-CLL. In conclusion, the molecular classification of CLL based on BcR IG stereotypy refines prognostication beyond IG mutational status and improves the Döhner hierarchical model. Hence, we suggest that a compartmentalized approach focusing on and comparing different subsets sheds light on CLL clinical behavior and biology and that BcR IG stereotypy represents a companion molecular diagnostic for personalized medicine in CLL. Disclosures Montillo: Janssen: Honoraria.

Abstract Background: Smudge cells are ruptured CLL cells seen on blood smears of CLL patients. For over a century, smudge cells were thought to represent an artifact of slide preparation. We recently showed that smudge cell formation was inversely proportional to leukemic B cell vimentin content. Vimentin is a cytoskeletal protein critical for lymphocyte rigidity and migration; high vimentin content is related to poor prognosis in CLL. Concordantly, in an initial small cohort of patients from a single institution, we found that patients with a low (<30%) percentage of smudge cells on a blood smear have a shorter time to treatment (Mayo Clin Proc.2007;82:449–53). In the current study, we evaluated the impact of smudge cell percentage on prognosis of patients with CLL seen at member institutions of the CLL Research Consortium (CRC). Methods: Archived blood smears from untreated patients with CLL were evaluated for smudge levels. All blood smears were prepared manually in a standard fashion from blood obtained by CRC Tissue Core and stained with WrightGiemsa stain. Smudge cells were defined as broken cells with no intact cytoplasm and a disrupted nuclear membrane. A total of 200 lymphocytes and smudge cells were counted on each slide and the results were expressed as the percent smudge cells. The association between the percentage of smudge cells, prognostic factors (IgVH status, CD38, ZAP-70 and FISH) and time to initial therapy (TTT) was examined. Results: We calculated smudge cell percentage on blood smears obtained prior to treatment for 337 CLL patients. The median smudge cell percentage was 32 (range 2–95%). The percentage of smudge cells was lower in CD38 positive patients (mean 33% vs. 38% in CD38 negative patients, p=0.04). No difference in smudge cell percentage was observed based on IgVH gene mutation status or Zap70 expression. Smudge cell percentage as a continuous variable was associated with prolonged TTT, exponential coefficient 0.98, p=0.04. Using our previously published cutoff of 30% to stratify patients in low and high risk categories, the estimated median time to first therapy of patients with smudge cell percentage ≤30% (n=178) was 7.8 years versus not reached in patients in patients with > 30% (n=159) of smudge cells, p=0.0036, (Figure 1). Ten years from diagnosis, 62% of patients with ≤30% of smudge cells versus 39% of patients with >30% of smudge cells required therapy. In multivariate analysis, the low percentage of smudge cells (≤30%) was an independent predictor of the shortened time to treatment (HR 1.86, 95%CI 1.09–3.16, p=0.02). Conclusion: This multicenter study confirms our initial finding that the percentage of smudge cells on a blood smear is an independent predictor of clinical outcome in patients with CLL. The estimation of smudge cell percentage on routine blood smear provides a simple and inexpensive prognostic test available to nearly all patients with a diagnosis of CLL worldwide. It also allows reanalysis and risk stratification of previously completed trials provided that blood smears have been archived. Further studies of the role of the cytoskeleton in CLL biology are warranted and ongoing in our laboratory. Figure Figure

Abstract Background: Historically, CLL patients with cytopenia were thought to have a poor prognosis and cytopenia is a key feature of CLL clinical staging systems. The implications of cytopenia in CLL could have changed because of improved diagnostic accuracy, increased recognition of early stage disease, and better treatments. Newer data suggest that the etiology of cytopenia determines its prognostic importance in CLL. Patients with cytopenia caused by autoimmune disease (AID) are less likely to have the poor prognosis associated with patients with bone marrow (BM) failure. To determine the prognostic significance of cytopenia in patients with CLL, we performed an observational study at Mayo Clinic Rochester (MCR). Methods: We studied all patients with CLL seen in the Division of Hematology at MCR from 1 January 1995 to 31 December 2004 (n = 1,750). Cytopenia (hemoglobin < 10 g/dL or platelet count < 100 × 09/L) was considered due to BM failure in patients with extensive BM involvement by CLL (< 20% residual myeloid tissue on BM biopsy) or reticulocytopenia without other causes persisting > 3 months after CLL therapy. Cytopenia was attributed to AID in patients with autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP), pure red blood cell aplasia (PRCA), or autoimmune granulocytopenia (AIG). Results: Median age at diagnosis of CLL was 63.7 years (69% male). Cytopenia occured in 423 (24.2%) patients. In 303 patients, cytopenia was due to CLL (228 BM failure and 75 AID). In 120 patients cytopenia was due to CLL related factors (splenomegaly, n = 11; possible AID, n = 18; treatment of CLL, n = 16) or non CLL causes (other malignancy, n = 12; iron deficiency, n = 11; anemia of chronic disease, n = 10; renal failure, n = 6; drugs effect, n = 4; surgical blood loss n = 4). In 28 (6.6%) patients the cause of cytopenia was not definitively determined. Of the patients with BM failure, 97 (43%) had cytopenia at CLL diagnosis (70% male, median age 63.3 years [range 32–95]), The AID patients the median age of CLL diagnosis was 66.7 years (range 30–85) with 79% male. AID diagnoses were AIHA (n = 41), ITP (n= 35), PRCA (n=8), and AIG (n=3); 9 patients had > 1 AID. Survival from diagnosis of cytopenia was significantly better for patients with AID (median 9.1 years) than BM failure (median 4.4 years, p < 0.001). AID patients had a longer survival from diagnosis of CLL (median 12.4 years) versus the rest of the CLL population (median 9.5 years, p = 0.020) but patients with BM failure at diagnosis had a worse prognosis (median 6.2 years, p < 0.001). Conclusion: We show that the etiology of cytopenia in CLL patients determines its prognostic importance. Anemia and thrombocytopenia caused by BM failure, but not AID, are associated with a significantly worse prognosis. These data show the importance of accurate determination of the etiology of cytopenia in all patients with CLL. Cytopenia in patients with AID is not a marker of advanced stage disease; these patients often need different management compared to those with BM failure. Cytopenia due to AID versus BM failure can be difficult to distinguish and a BM study should be done in all patients considered for treatment. Patients with cytopenia due to AID cannot be meaningfully classified by current clinical staging systems. We believe that efforts to review the NCI-WG 96 criteria are timely and should consider the etiology of cytopenia in CLL patients.

Abstract Background Although hypogammaglobulinemia is a well-recognized complication in patients with chronic lymphocytic leukemia (CLL), its prevalence at the time of CLL diagnosis and association with novel prognostic markers and clinical outcomes are not well understood. Methods All patients seen at Mayo Clinic between 1/1995 - 4/2013 with newly diagnosed CLL (<12 months diagnosis) and who had baseline assessment of serum immunoglobulin G (IgG) were included in this analysis. Baseline demographic and clinical characteristics as well as serum IgG levels measured by either immunoassay or serum protein electrophoresis analysis were recorded. Based on the normal range for IgG at our laboratory, patients with serum IgG<757 mg/dL were classified as having hypogammaglobulinemia. Patients with IgG<757 were also further stratified by terciles (lower tercile: IgG<585 mg/dL; middle tercile: IgG 585-687 mg/dL, upper tercile: IgG 688-756 mg/dL). The relationship between hypogammaglobulinemia at diagnosis and prognostic parameters including immunoglobulin heavy chain (IGHV) gene mutation status, genetic abnormalities detected by fluorescence in-situ hybridization (FISH), and ZAP-70, CD38 and CD49d expression was assessed. Associations of hypogammaglobulinemia with time to first treatment (TTT) and overall survival (OS) was also evaluated. Results Of 1485 patients who met the eligibility criteria, 382 (26%) had hypogammaglobulinemia (median IgG=624 mg/dL) at the time of CLL diagnosis while the remaining 1103 (74%) had normal serum IgG levels (median IgG=1040 mg/dL). Baseline demographic and clinical characteristics of patients with and without hypogammaglobulinemia are shown in Table 1. When patients with hypogammaglobulinemia (IgG<757 mg/dL) were further stratified into terciles, patients in the lower tercile (n=127) were more likely to have advanced Rai stage (III-IV) at diagnosis (15% vs. 6% vs. 4%, p=0.008), be CD49d positive (56% vs. 43% vs. 32%, p=0.01), and have trisomy 12 on FISH testing (29% vs. 24% vs. 9%, p=0.005) compared to patients in the middle (n=127) and upper (n=128) terciles. After median follow-up of 4.2 years, 479 (32%) patients had received treatment for CLL, and 328 (22%) patients had died. The median TTT for patients with hypogammaglobulinemia was 3.8 years compared to 7.4 years for patients with a normal IgG (p-value<0.001). Among patients with hypogammaglobulinemia, the median TTT for patients in the lower, middle, and upper terciles were 1.7, 2.9, and 6.3 years respectively (p-value<0.001, Figure 1). On multivariable analysis that included age, gender, Rai stage, IGHV mutation status, FISH risk category and hypogammaglobulinemia, the following were independently associated with a shorter TTT: advanced (III-IV) Rai stage (hazard ratio [HR] =15.3, p<0.0001); intermediate (I-II) Rai stage (HR=3.0, p<0.0001); unmutated IGHV (HR=2.6, p=<0.0001); and hypogammaglobulinemia (HR=1.5, p=0.02). Conclusion In this large cohort study, approximately one-quarter of CLL patients had a low serum IgG level at the time of diagnosis. High-risk features, including advanced Rai stage and expression of CD49d, were associated with greater risk of hypogammaglobulinemia at the time of diagnosis. Patients with hypogammaglobulinemia at diagnosis had shorter TTT, a finding that persisted after adjusting for other prognostic factors. Evaluation of acquired hypogammaglobulinemia during the course of follow-up among patients who initially had normal IgG levels is ongoing. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

Abstract Introduction Approximately 2-8% chronic lymphocytic leukemia (CLL) patients develop diffuse large B-cell lymphoma (DLBCL, so-called Richter syndrome [RS]) over long-term follow-up. The outcomes of patients with RS are variable and poorly understood. Methods CLL patients seen at Mayo Clinic from January 1995 to April 2013 who developed biopsy-proven DLBCL during follow-up were included in this analysis. Clinical characteristics, therapy and overall survival (OS) of all patients with RS were analyzed. Results One hundred and twenty patients with biopsy-proven RS were identified in the Mayo Clinic database. The median age at diagnosis of RS was 67 years (range, 29-88 years), 87 (73%) were male, and 83 (69%) had received prior CLL therapy. The median duration between diagnosis of CLL and development of RS was 3.8 years (range, 0-34.5 years). Stereotyped B-cell receptors were found in 9/30 (30%) RS patients compared to 219/1294 (17%) non-RS patients (OR=2.1, p=0.07). IGHV4-39 gene usage was present in 2/26 (8%) RS patients compared to 57/1354 (4%) non-RS patients (p=0.3). Of the 30 RS biopsy samples in which Epstein Barr virus (EBV) in-situ hybridization studies were performed, EBV was detected in 7 (23%) patients. After a median follow-up of 5.2 years, 86 (72%) patients have died. Causes of death were as follows: progressive DLBCL (n=46, 53%), progressive CLL (n=2, 2%), infection (n=8, 9%), unknown (n=20, 23%) and other (n=10, 12%). The median OS of the entire cohort was 0.9 years (95% CI, 0.5-1.3 years). Tsimberidou and colleagues proposed a prognosis score (RS score) based on the following variables at the time of RS diagnosis: Eastern Co-operative Group performance status of 2-4, lactate dehydrogenase >1.5 x normal, platelets<100 x 109/L, tumour size >5 cm and >1 prior therapy for CLL. Each parameter was assigned one point, and patients were then assigned to one of four risk groups based on their calculated RS score: 0 or 1, low risk; 2, low-intermediate risk; 3, high-intermediate risk; 4 or 5, high risk. The OS according to the RS score for our group of patients is shown in Figure 1. Median survival in the low, intermediate-1, intermediate-2 and high-risk groups were 2.4 years, 0.7 years, 0.3 years and 0.2 years, respectively (p<0.001). Fifteen (12%) patients received cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) as initial therapy for RS, and 68 (57%) received rituximab in addition to CHOP (R-CHOP). There was no difference in survival among patients who received CHOP compared to R-CHOP (median, 1.8 years. vs. 1.2 years, p=0.5). Twenty-four patients (20%) received non-CHOP-based chemotherapy, and treatment was unknown in 4 (3%) patients. Nine patients (7%) died before definitive therapy could be instituted. Thirteen (11%) patients were able to proceed to stem cell transplantation (SCT): 10 (8%) autologous SCT, 2 (2%) allogeneic SCT and 1 (1%) autologous SCT followed by an allogeneic SCT. Although RS patients who underwent SCT were younger compared to those who did not undergo SCT (median, 59 years. vs. 69 years, p=0.001), no differences in prior CLL therapy or receipt of R-CHOP therapy for DLBCL was noted between the two groups. The median survival of patients who proceeded to SCT was superior compared to those who did not (5.2 years vs. 0.7 years; p=0.005). Conclusion Stereotyped B-cell receptors but not VH4-39 had a suggested evidence of an increased risk of RS in our cohort. Although 90% RS patients received intensive chemotherapy, only 11% patients were able to proceed to SCT. Median survival of RS patients remains dismal at 1 year, and newer therapies are needed to improve outcomes. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

Abstract Introduction We have previously developed a primary human bone marrow model in CLL which allows us to study marrow derived mesenchymal stroma cells (MSC) and mimic in vivoMSC-leukemic interactions in CLL (Ding, Blood, 2010) These interactions proved to be bidirectional with functional implications for both cell types. However the biologic and clinical implications of these bilateral cellular interactions in relation to MSC function in CLL patients have not been completely studied. MSC are clearly established as an essential component in forming supportive marrow niches for hematopoiesis. Our focus in this study thus was to further investigate on the status of CLL MSC function in comparison with normal MSC and the impact of the leukemic CLL B cell on MSC function and its role in forming marrow niches in CLL. Methods Bone marrow (BM) aspirates of CLL patients or normal age-matched subjects were used to generate MSC and these MSC were then assessed for various functions. Specifically we assessed the growth, differentiation capacity, gene expression, cytokine secretion profile and transcriptome analysis of CLL and normal MSC using colony forming unit (CFU) assay, MSC differentiation assay, Affymetrix U133 2.0 plus array and RNA sequencing respectively. To determine MSC CFU frequency, fixed number of nucleated cells (5 or 10 million) from BM aspirates were added in MSC growth medium for 10 days to form CFU. CFU frequency was then calculated by dividing the number of MSC colonies by the fixed number of inputted nucleated cells. In order to test the specific gene changes that occurred in MSC after their interaction with CLL leukemic cells, normal MSC were co-cultured with CLL cells for 1 week and subsequently followed by cell growth, gene expression analysis with RNA sequencing and cytokine profiles using a multiplex assay. Results CLL MSC generated significantly lower CFU colonies compared to normal subjects (CLL [n=24] vs normal [n=6] mean: 2.2 vs. 22 CFU per million nucleated cells, p=0.01). In order to test if the lower number of CLL MSC CFU was due to their reduced growth capacity or lower frequency, we then performed the CFU assay using identical numbers of CLL and normal MSC at the start of culture. CLL MSC was found to have significantly lower CFU capacity compared to normal MSC (mean: 2.1 [CLL] vs 4.5 [normal] CFU/10 input cell, n=7 in each group, p=0.03). To investigate the mechanism(s) for the reduced growth capacity of CLL MSC, we compared the gene expression profiles of non-stimulated CLL vs. normal MSC (n=10 for each group) with the following outcomes: CLL MSC had increased expression of cell cycle inhibitor: p16(Ink4a) and p57, both key markers of cell senescence (Baker, Nature, 2011); CLL MSC overexpressed homeobox B cluster of transcription factors, key regulator for cell development and differentiation. Wnt inhibitors DKK1/DKK2 and non-canonical Wnt 5b known to be associated with aging were found to be 10 and 2 fold more elevated in CLL MSC. In addition, MSC abundantly produced a milieu of the cytokines MCP-1/IL-8/IL-6/IL-1Ra after interaction with CLL leukemic cells. These cytokines are associated with a senescent associated secretory phenotype (SASP). Co-culture experiments of normal MSC with CLL Leukemic cells revealed significant impact of leukemic cells on normal MSC functions. Co-culture with a low density of CLL leukemic cells (CLL to MSC ratio: ≤10,000/1) increased MSC growth (1.2 fold). However, high density co-culture of CLL cells with MSC (CLL to MSC ratio of 100,000/1) inhibited MSC growth (0.8 fold). Transcriptome analysis of normal MSC before and after one week of co-culture with CLL leukemic cells showed that normal MSC had alteration of ~1500 genes. Many of the modified genes (CDKN2B, DKK2, LIF, HGF, FOXQ1 etc) are known to be involved in regulation of cell growth and senescence. Conclusion Collectively, these results demonstrated that bone marrow derived CLL MSC have decreased proliferative potential and possess senescent phenotypes. Importantly these senescent features were inducible in normal MSC after their interaction with CLL leukemic cells implying that leukemic B cells can educate MSC to become senescent. The implications of the CLL MSC senescence status are multiple and include: defective hematopoietic niches due to dysfunctional MSC, immune dysregulation and the enhanced nurturing of CLL B cell by these MSC. We are now investigating several of these latter features in our current work. Disclosures Shanafelt: Genentech: Research Funding; GlaxoSmithKline: Research Funding; Celegene: Research Funding; Cephalon: Research Funding; Pharmacyclics/Jannsen: Research Funding; Hospira: Research Funding; Polyphenon E Int'l: Research Funding. Kay:Genetech: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees.

Abstract BACKGROUND: Although chemoimmunotherapy (CIT) has improved response rates, treatment free survival, and overall survival in patients with chronic lymphocytic leukemia (CLL), only 40-50% of patients achieve a complete remission and the majority have residual disease when evaluated using sensitive assays. Interactions with nurturing environments can enhance CLL B-cell resistance to apoptosis. These interactions include cytokine mediated prosurvival signals by angiogenic molecules, such as VEGF and bFGF that nurture CLL B-cells in an autocrine fashion and promote CLL cell survival partly through up regulation of anti-apoptotic proteins. These findings provide a strong rationale for testing anti-VEGF therapy in combination with a purine nucleoside analogue CIT regimen for upfront treatment. We conducted a randomized phase 2 CIT trial using pentostatin, cyclophosphamide, and rituximab with (PCR-B) or without (PCR) bevacizumab (B), an anti-VEGF monoclonal anti-body. METHODS: Eligible patients were previously untreated and had CLL in need of treatment by NCI-WG criteria (Blood 111:5446). Patients were randomized using a dynamic allocation procedure stratifying for stage (0-II vs. III-IV) and FISH (17p or 11q deletion vs. other) to receive either 6 cycles of rituximab (100 mg on day 1 of cycle 1; 375 mg/m2on day 2 of cycle 1 and day 1 of cycles 2-6) followed by pentostatin (2 mg/m2) and cyclophosphamide (600 mg/m2) (PCR) administered every 21 days. Patients in the PCR-B cohort also received bevacizumab 15mg/kg on day 1 of cycles 1-5 and days 1, 22, & 43 of cycle 6. All patients underwent complete response evaluation 3 months after day 1 of cycle 6 (or last cycle of treatment for those completing < 6 cycles). MRD was assessed using 6-color flow cytometry (Leukemia 21:956) at the completion of treatment. RESULTS: 68 patients were enrolled through the Mayo Clinic Cancer Research Consortium between 1/2009 and 1/2013. Three patients were excluded from analysis: 1 patient canceled prior to treatment, 1 was dosed incorrectly, and 1 was ineligible due to immunophenotyping inconsistent with CLL. Median age of eligible patients was 63 years (range 43-81) and 43 (66%) were men. With respect to disease stage, 3 (5%), 38 (58%), and 24 (37%) had low, intermediate and high Rai stage disease. Eleven (17%) patients had deletion 17p or 11q & 29 (45%) had unmutated IGHV. No statistically significant differences were observed in these variables by treatment arm. All 65 evaluable patients have completed active treatment, with 54 (83.1%) completing the intended 6 cycles (PCR group 27/32 [84.4%] and PCR-B 27/33 [81.8%]). Hematologic grade 3+ adverse events deemed at least possibly related to treatment were observed in 10 (31.3%) patients on PCR and 12 (36.4%) on PCR-B (p=0.79). Non-hematologic grade 3+ adverse events deemed at least possibly related to treatment were observed in 9 (28.1%) patients on PCR and 18 (54.4%) on PCR-B (p=0.04). The most common such events were hypertension (PCR: 3.1% vs. PCR-B: 21.2%), proteinuria (0% vs. 6.1%) and creatinine increase (3.1% vs. 6.1%). Across both arms, 64/65 (98.5%) patients achieved a response including 31/32 (96.9%) treated with PCR and 33/33 (100%) treated with PCR-B (p=0.49). CR/CRi was achieved in 10/32 (31.3%) patients treated with PCR & 18/33 (54.5%) treated with PCR-B (p=0.08). Of the 28 who achieved a CR/CRi, MRD analysis was completed on 26, of whom 12 (46%) were MRD negative. With respect to treatment arm, 5/32 (16%) patients on PCR and 7/33 (21%) on PCR-B achieved an MRD negative CR. Median time to retreatment for all 65 patients was 44.8 (95% CI: 34.6 – NA) months. Median overall survival has not yet been reached. With current follow-up no differences between treatment-free survival (p=0.38), progression-free survival (p=0.23), or overall survival (p=0.45) are observed by treatment arm. Plasma levels of angiogenic cytokines VEGF, bFGF, thrombospondin (TSP) and the chemokines CCL3 and CCL4 were measured prior to treatment and at the time of the post treatment response evaluation. Correlations of these cytokines with clinical outcome will be presented. CONCLUSION: The addition of bevacizumab to purine analogue-based CIT was generally well-tolerated and may increase complete remission rates in patients with CLL. No clear improvement in treatment free survival has been observed to date. Disclosures Shanafelt: Hospiria: Research Funding; Pharmacyclics/Jannsen: Research Funding; Cephalon: Research Funding; Celgene: Research Funding; glaxoSmithKline: Research Funding; Genetech: Research Funding; Polyphenon E Int'l: Research Funding. Off Label Use: Off label use of pentostatin for treatment of CLL. Off label use of bevacizumab for treatment of CLL. . Kay:Genetech: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees.