Call, Timothy G.

Abstract Introduction: Richter transformation (RT) refers to transformation of chronic lymphocytic leukemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Most studies on the management of RT were either small retrospective series or early phase non-randomized trials before the era of novel agents. The natural history, prognostication and optimal treatment of patients with RT remain undefined. Here we report the clinical characteristics and outcomes of a large series of RT from a single center. Methods: Biopsy-confirmed RT (limited to non-Hodgkin lymphoma) diagnosed from 4/1993 to 4/2018 were identified from the Mayo Clinic CLL database. Clinical characteristics, treatment information and follow-up data were abstracted by chart review. Overall survival (OS) was defined as time from RT diagnosis to death from any cause and analyzed using the Kaplan-Meier method. Statistical analysis was done in SAS 9.4. Results: A total of 204 patients with CLL who developed RT were identified. The median age at CLL diagnosis was 62 years (range 22-85), and 148 (73%) were male. The median time to transformation was 4.7 years (range 0-34.5). Prior to RT, 68 (33.3%) patients received no treatment for CLL, 109 (53.4%) received chemoimmunotherapy (CIT) only, and 27 (13.2%) received at least one novel agent (idelalisib, ibrutinib, or venetoclax) for CLL. The median lines of CLL therapy prior to RT was 2 (range 0-13). The median age at RT diagnosis was 69 years (range 30-88). Pathology of RT was DLBCL and high grade B-cell lymphoma in 193 (94.6%) and 11 (5.4%) patients, respectively. The median LDH was 306 IU/L (range 99-9000). 62/125 (49.6%) patients had bulky disease (≥ 5 cm), and the median PET SUVmax was 13.9 (range 2.9-30.0). 45/131 (34.4%) patients had del(17p) or TP53 mutation, 12 (9.2%) had del(11q), 21 (16.0%) had trisomy 12, 27 (20.6%) had del(13q), and 25 (19.1%) had normal FISH. The CLL and RT were clonally related in 12/21 (57.1%) patients. For the transformed lymphoma, cell of origin by Han's algorithm was germinal center B cell-like (GCB) and non-GCB in 31/100 (31.0%) and 69/100 (69.0%) patients, respectively. EBV was positive in 14/52 (26.9%) patients. The median Ki-67 was 80% (range 10-100). Myc and Bcl-2 were positive by IHC in 31/43 (72.1%) and 83/103 (80.6%) patients, respectively; 27/56 (48.2%) were double-expressors. MYC, BCL2, and BCL6 rearrangement was positive by FISH in 18/68 (26.5%), 10/34 (29.4%), and 4/31 (12.9%) patients, respectively; 8/66 (12.1%) were double/triple-hit. The most common first-line treatment (Table 1 notes) of RT was R-CHOP-like regimen (n=114, 65.5%). Other treatments included R-EPOCH-like (n=6, 3.4%), high-intensity chemotherapy (n=15, 8.6%), novel agents (eg, ibrutinib, venetoclax, pembrolizumab; n=19, 10.9%), other chemotherapy (n=12, 6.9%), and palliative therapy (n=8, 4.6%). Response to first-line treatment was CR in 57 (38.0%), PR in 33 (22.0%), SD in 18 (12.0%), and PD in 42 (28.0%) patients. The median OS of the entire cohort after RT diagnosis was 12.0 months. The median OS for patients who received no prior CLL treatment, CIT only or at least one novel agent for CLL were 65.5, 7.3, and 12.0 months, respectively (P<0.0001; Figure 1). Of note, in patients who received CIT only for CLL, ~10% and 60% received high-intensity and R-CHOP/R-EPOCH-like chemotherapy, respectively, as first-line RT therapy. In contrast, in patients who had prior novel agents for CLL, 56% and 26% were treated with novel agents and R-CHOP/R-EPOCH-like chemotherapy, respectively, as first-line RT therapy. Patients with or without del(17p)/TP53 mutation had a median OS of 8.3 and 12.8 months, respectively (P=0.046). Patients who were treated with high intensity chemotherapy, R-CHOP/R-EPOCH-like regimens, novel agents, and other therapies for RT had a median OS of 35.1, 14.4, 10.9 and 6.1 months, respectively (P=0.02; Figure 2). OS comparisons by CLL/RT clonal relationship, double expressor or double/triple-hit status are shown in Table 1, with no significant differences noted. Conclusions: Over two thirds of RT were the non-GCB subtype, and about half were Myc/Bcl-2 double expressors. Patients who developed RT without prior CLL therapies had a significantly better OS. In contrast, patients who had received prior CLL therapies had poor outcomes. Myc/Bcl-2 double expressor and MYC/BCL2/BCL6 double/triple hit status had no impact on OS. Disclosures Kenderian: Humanigen: Research Funding; Novartis: Patents & Royalties; Tolero Pharmaceuticals: Research Funding. Kay:Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees. Parikh:Janssen: Research Funding; Abbvie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; MorphoSys: Research Funding; Gilead: Honoraria; Pharmacyclics: Honoraria, Research Funding. Ding:Merck: Research Funding.

Abstract Introduction: Given the established role of PD-1 in mediating immune suppression in chronic lymphocytic leukemia (CLL), we tested and reported the efficacy of PD-1 blocking antibody pembrolizumab in relapsed and transformed CLL patients. A selective response of pembrolizumab (~40%) in patients with RT, particularly after prior ibrutinib, was observed (Ding, Blood, 129:3419). Correlative analysis showed PD-1 expression in tumor B-cells of patients with RT and aggressive CLL after progression on ibrutinib. PD-1, an inhibitory receptor expressed on CLL T-cells, inhibits the immune synapse and cytotoxic T cell functions via the interactions with its ligands. However, the expression pattern and role of PD-1 in tumor B-cells is not well defined. In this study we investigated the functional implication of the PD-1 signaling axis in B-cell pathobiology in CLL and RT patients. Methods: 26 CLL-involved lymph node (LN) and 20 RT-involved LN were tested for PD-1 expression by immunohistochemistry (mouse clone NAT105, Abcam). For in vitro study, we checked PD-1 expression in 11 lymphoma cell lines and 1 CLL cell line by both flow cytometry and Western blot (WB) analysis. Effect of PD-1 knockdown using CRISPR/Cas9 system (Addgene) and over-expression of PD-1 using pLEX-lentiviral (Thermoscientific) or pRetro-retroviral (Clonetech) system were evaluated on pro-survival and apoptotic signaling pathways by Western blot analysis. Gene expression signatures in CLL and RT patients were also evaluated by Illumina-based RNA sequencing using FFPE-nodal tissue obtained by clinical biopsy (Tempus Labs; Chicago, IL). Results: The expression of PD-1 was significantly increased in RT-LN compared to CLL-LN. (mean ± SEM in RT vs. CLL, 30.6 ± 4.7 vs. 11.5 ± 2.8, p < 0.001). PD-1 expression was highest in patients with RT where the immediate prior CLL therapy was ibrutinib (Figure 1A). Among all cell lines tested for PD-1 expression, the expression of PD-1 by WB and flow was highest in Mino (mantle cell lymphoma line), followed by moderate expression in Jvm2 (B-PLL line) and Mec1 (CLL line), and very low-level expression in both Jeko-1 (B-NHL line) and lymphoma line 'Karpas299'. CRISPR/Cas9 mediated depletion of PD-1 in Mino cells inhibited constitutively active Akt, p70S6K and mTOR pathway, accompanied by significant downregulation of the anti-apoptotic proteins, Bcl-2, Mcl-1 and XIAP, but P-ERK1/2 was not affected. Constitutive lentiviral (pLEX-PD-1)-mediated overexpression of PD-1 in Jeko-1 and doxycycline regulated inducible retroviral (pRetro-PD-1) mediated overexpression of PD-1 in Karpas299 activated Akt, mTOR and p70S6K pathway. Overexpression of PD-1 in Jeko-1 significantly increased Bcl-2 and Mcl-1 and in Karpas299 increased Bcl-2, Mcl-1 and XIAP expression (Figure 1B). A parallel genetic analysis using RNA sequencing was performed on 5 nodal tissues involved by either RT or progressive CLL after these patients developed clinical progression after prior ibrutinib therapy. In all 5 patients, overexpression of PD-1 was associated with increased expression of Bcl-2 and mTOR regardless of the genetic mutations detected (including TP53, ATM, BTK, NOTCH1, XPO1, SF3B1, TET2 etc). However, in 2 patients who received prior chemoimmunotherapy, similar overexpression of gene signature was not observed by RNA sequencing analysis, alternative pathways including Met or NFkB overexpression was detected. Given these clinical and laboratory findings, we have treated 2 RT patients with a combination of BTK and Bcl-2 inhibitors (ibrutinib and venetoclax, respectively) whose CLL transformed after prior ibrutinib. Significant reduction of tumor burden was observed in both cases with one complete response and one mixed response. Conclusion: An increased expression of PD-1, Akt/mTOR and Bcl-2 gene signature was first observed in RT patients after prior ibrutinib therapy. PD-1 overexpression in the tumor B-cells of RT and progressive CLL patients likely regulate AKT/mtOR to upregulate Bcl-2. Targeting both BTK and Bcl-2 pathways in addition to PD-1 blockade appear to be a promising strategy to treat these aggressive diseases. Disclosures Parikh: Gilead: Honoraria; Janssen: Research Funding; Abbvie: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; AstraZeneca: Honoraria, Research Funding. Kenderian:Novartis: Patents & Royalties; Tolero Pharmaceuticals: Research Funding; Humanigen: Research Funding. Ansell:Takeda: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Celldex: Research Funding; Merck & Co: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Pfizer: Research Funding. Kay:Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees. Ding:Merck: Research Funding.

Abstract Background Predictors of outcomes after reduced intensity conditioning (RIC) stem cell transplantation (SCT) in chronic lymphocytic leukemia (CLL) are not well established. The Dana Farber (DF) investigators (Brown et al, leukemia 2013) developed a prognostic scoring model for overall survival (OS) and disease free survival (DFS) that assigned one point to each of comorbidity index, absolute lymphocyte count, LDH and disease status. The goals of the present study were to 1) validate the DF model 2) identify additional predictors of outcomes after SCT. Methods This study is a retrospective review of the Mayo Clinic CLL database and was approved by the Institutional Review Board. All CLL patients that underwent RIC-SCT were included. The prognostic significance of prognostic factors at time of RIC-SCT were analyzed, including the DF model. Survival was estimated and compared using the Kaplan Meier and Log Rank tests. Results From 2006 to 2012, 50 patients with CLL underwent RIC-SCT at the Mayo Clinic. Of these, 33 were male (66%) and the median age was 56 (29-69) years. The median time from diagnosis to RIC-SCT was 4.7 years (0.6-22.9). Indications for RIC-SCT were 17p deletion in 24 (48%) patients and purine nucleoside analogue (PNA) refractory disease in 26 (52%) patients. Transplant related mortality was 6% and non-relapse mortality at 5 years was 14%. Acute graft versus host disease (GVHD) developed in 30 (60%) patients and chronic (c) GVHD was noted in 32 patients (64%). The 5-year relapse rate was 38%. The DF prognostic score stratified three categories for OS (score of 0, 1-2, ≥ 3), but was not associated with DFS in this cohort. We next evaluated the impact of other patient, disease, and transplant characteristics on clinical outcome. Development of cGVHD post-transplant was the dominant predictor of both DFS (HR 0.26, 95% CI=0.10-0.69, P=0.006) and OS (HR 0.04, 95% CI=0.01-0.19, P<0.0001, figure 1). The presence of 17p deletion at time of RIC-SCT was associated with shorter DFS (HR 3.99, 95% CI=1.43-11.18, P=0.008), but did not impact OS. Developing cGVH but not DF score remained an independent predictor of OS on a multi-variate analysis including both factors. Given these findings, we evaluated what pre-treatment patient, disease, and transplant characteristics predicted for subsequent development of cGVHD. Patients with higher scores on DF prognostic model were less likely to develop cGVHD (score 0=66%, 1-2=76%, ≥3=31%; P=0.01). Three CLL characteristics (complete or partial remission at time of RIC-SCT, absence of 17p deletion, and absence of ZAP70 overexpression) were predictors for development of cGVHD while alemtuzumab exposure ≤3 months prior to RIC-SCT decreased likelihood of cGVHD. On multivariate modeling using these four predictors, only ZAP70 overexpression was an independent negative predictor of developing cGVHD (Table 1). Rates of cGVHD post RIC-SCT in ZAP 70 positive and ZAP70 negative patients were 50% and 92%, respectively (p=0.03). Conclusion This study found that while the DF prognostic score is an effective way to predict outcome prior to RIC-SCT, development of cGVHD post-transplant is ultimately the most significant predictor for both OS and DFS after transplant in patients with CLL. Pretransplant characteristics that predict subsequent cGVHD include DF prognostic score and ZAP70 status. This is the first report to identify biologic characteristics of CLL B-cells associated with development of cGVHD post-transplant. Disclosures: No relevant conflicts of interest to declare.

Abstract Clonal hematopoiesis of indeterminate potential (CHIP) is defined as somatic mutations in clonal blood cells of individuals without any other hematological abnormalities and have been identified using whole exome sequencing (WES) from pre-specified genes. CHIP is reportedly associated with aging, reduced overall survival, cardiovascular disease, and hematologic disease, mainly myeloid cancers. Additionally, whole genome sequencing and WES studies in CLL cases have identified putative CLL driver genes with recurrent somatic variants or copy number alterations. Here, we investigate the associations of CHIP and mutations in CLL somatic driver genes with risk of CLL and MBL, a precursor to CLL. Using WES, 571 individuals from 132 CLL families were sequenced from two different sites, Mayo Clinic (92 families) and National Cancer Institute (NCI, 40 families), including 251 CLLs, 74 MBLs, and 246 unaffected relatives. DNA was extracted from buccal cells (Mayo Clinic) and peripheral blood (NCI). Allele counts from gVCF files were extracted for specific genes and analyzed. Variants were annotated using the Variant Effect Predictor in Ensembl, genome build GRCh37 (http://useast.ensembl.org/index.html). Highly-sensitive flow cytometry of the blood was used to screen for MBL. CHIP was defined as in Genovese et al., 2014 as the presence of any of the following: A) disruptive mutations in ASXL1, TET2, or PPM1D; B) missense mutation p.617F in JAK2; C) disruptive or missense mutations in DNMT3Alocalized to exons 7 to 23D) any mutations reported at least 7 times in hematological malignancies in the Catalogue of Somatic Mutations in Cancer (COSMIC); and (E) No variant allelic fraction (VAF) threshold. CLL driver genes included disruptive or missense mutations in ATM, BIRC3, MYD88, NOTCH1, SF3B1, TP53, EGR2, POT1, NFKBIE, XPO1, or FBXW7with VAF greater than 0.1. Mutations from COSMIC and CLL driver genes were excluded if the minor allele frequency in 1000 Genomes was greater than 0.5%. Data was analyzed using logistic regression adjusting for age, sex, and site. Odds ratios (OR) and 95% confidence intervals (CI) were estimated. Median age for CLL, MBL, and unaffected was 63, 61.5, and 54, respectively. The unaffected relatives were significantly younger than both the CLL and MBL groups (p<0.0001), with no difference between CLL and MBL (p=0.46). A total of 70 (12%) individuals from 54 different families had CHIP. CHIP was characterized in the majority of samples as mutations in DNMT3A, ASXL1, and TET2with 43, 9 and 8 individuals, respectively. As expected, CHIP was associated with age (p<0.001) but not sex (p=0.87). CHIP was present in 42 (17%) CLLs, 9 (12%) MBLs, and 19 (8%) unaffected relatives. There was a significant association between the presence of CHIP and CLL risk compared to unaffected relatives (OR= 2.19, 95% CI: 1.20 - 4.13, p=0.013) but not with MBL risk (OR=1.34, 95% CI: 0.54 - 3.11, p=0.51). Using the CLL driver genes, we found mutations in 119 (47%) CLL, 20 (27%) MBL, and 70 (29%) unaffected relatives. Mutations in CLL driver genes were associated with CLL risk compared to unaffected relatives (OR = 2.51, 95% CI: 1.64 - 3.87, p<0.0001), but there was no evidence for increased MBL risk (OR = 1.00). These results held when we subset the analysis to the Mayo only data where the DNA was extracted from buccal cells. This study further supports the association between mutations in CHIP related genes and risk of hematologic malignancies, in particular CLL. This is the first report of the prevalence of CHIP in MBLs. Although MBL and CHIP represent clonal population of blood cells, our data suggest the clones are different. Mutations in CLL driver genes are also associated with CLL risk but show little to no evidence with increased MBL risk. Interestingly, our unaffected relatives of CLL cases also had a high frequency of CLL driver mutations. Future studies are needed to understand these acquired mutations (both in CHIP- and CLL driver- related genes) in the unaffected to MBL to CLL continuum. Disclosures Parikh: Abbvie: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; AstraZeneca: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Research Funding. Ding:Merck: Research Funding. Cerhan:Jannsen: Other: Scientific Advisory Board; Celgene: Research Funding; Nanostring: Research Funding. Shanafelt:Jansen: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; GlaxoSmithKline: Research Funding. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract Backgrounds B cell receptor (BCR) signals and microenvironment protection have been recognized to have key influences on CLL survival and activation. Akt activation is down-stream of the BCR signaling cascade and is critical in the mediation of the bi-directional interactions between CLL B-cells and bone marrow stroma. MK2206 is an allosteric Akt inhibitor previously tested for safety in solid tumor patients. Our preclinical data has demonstrated the synergy of MK2206 with bendamustine (B) to induce CLL apoptosis in vitro. MK2206 also abolished the signal activation and cytokine production induced by BCR ligation in CLL leukemic cells (Ding, ASH 2012). Therefore, we conducted a phase 1 trial testing the safety and efficacy of MK2206 in combination with bendamustine and rituximab (BR) for patients with relapsed/refractory CLL. Methods A phase 1 dose-escalation study was designed to define the maximum tolerated dose (MTD) as well as the safety and efficacy of 3 dose levels (90 mg or 135 mg or 200 mg weekly) of the oral Akt inhibitor MK2206 in combination with bendamustine (70 mg/m2 daily for 2 days in each cycle) and rituximab (cycle 1: 375 mg/m2, cycle 2-6: 500 mg/m2) therapy in relapse/refractory CLL patients. To test the targeting efficacy of MK2206 on Akt and downstream signals, we designed a one-week “run-in” of single agent MK2206 before the initiation of BR during cycle 1. MK2206 was then given along with BR on day 1 of cycles 2-6. Tumor response was evaluated 2 months after the 6th/last cycle of therapy based on IWCLL 2008 criteria. Correlative laboratory studies included assessment of Akt signaling and the plasma cytokine levels (multiplex beads assay (Invitrogen)) at baseline and after one week of first dose of single agent MK2206. Results Nine patients (median age 68) were enrolled in the phase I portion of this trial. All 9 patients had unmutated immunoglobulin heavy chain variable region genes (IGHV) and 4 had del(11q). Six had received prior chemoimmunotherapy (CIT: FCR or PCR or PCO) and 5 had high risk disease defined as early progression within 26 months of the last CIT. Three had received alemtuzumab containing regimen. We have observed potent lymphocyte mobilization in all evaluated patients (n=7) after one-dose of MK2206 during week 1 (mean increase ALC: 35%) as well as reductions of plasma CCL3, CCL4 and CCL2 in the majority of the patients. A single dose-limiting toxicity (DLT) (febrile neutropenia and hemolytic anemia) was observed at dose level 1 (90 mg weekly) among 6 patients treated at this dose. Two patients with dose-limiting toxicities at dose level 2 (135 mg weekly) were observed where one patient had a rash and one patient had dehydration and febrile neutropenia among three patients treated at this dose. Accordingly, the 90 mg once weekly dose was determined to be the MTD for phase 2 trial testing. The most frequent grade 3 or 4 adverse events observed to date were neutropenia (44%) including febrile neutropenia (22%), rash (22%), diarrhea (22%), nausea and vomiting (11%), dehydration (11%), hemolytic anemia (11%) and thrombocytopenia (11%). The frequency of cytopenias was similar to the published German experience with BR (50% grade 3 or 4 hematological toxicities compared to 44% in N1087) in relapsed CLL patients (Fischer, JCO 2011). The median number of cycles received was 6 (range 1-6). Using an intent to treat analysis, two patients achieved complete response (CR, n= 2, 22%), one patient achieved nodular partial response (nPR, n=1, 11%) and five patients achieved a partial response (PR, n=5, 56%). The overall response rate (ORR) is 89%. Conclusion The Akt inhibitor MK2206 in combination with BR is well tolerated in patients with relapsed/refractory CLL. Single dose of MK2206 inhibits Akt phosphorylation, mobilizes leukemic cells and decreases plasma cytokines involved in BCR signals. The preliminary efficacy of this combination demonstrated promising results with a 89% ORR and 22% CR albeit in the small phase 1 cohort. These results compare favorably to BR alone (9% CR and 59% ORR) in relapsed/refractory CLL patients. Phase 2 testing of this combination is now underway. Acknowledgment This work was supported by the funding from NCI grant K23CA160345 (WD), NCI grant CA95241 (NEK) and Alliance for Clinical Trials in Oncology (CA025224 and CA33601). Disclosures: Off Label Use: MK2206, used in a phase 1 trial of relapsed CLL disease. Shanafelt:Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding. Zent:Novartis: Research Funding; GlaxSmithKline: Research Funding; Biothera: Research Funding; Genzyme: Research Funding; Genentech : Research Funding. Reeder:Celgene: Research Funding; Novartis: Research Funding; Millenium: Research Funding.

Abstract Background MBL is a precursor state to CLL, with a prevalence of ~5-8% in the general population and 15-18% in CLL families. To date, 41 single nucleotide polymorphisms (SNPs) have been found to be associated with CLL. We previously showed that a PRS of the weighted average of the number of risk alleles of these SNPs is associated with CLL risk using cases and controls from the International Lymphoma Epidemiology (InterLymph) Consortium. We validated this score in an independent sample of CLL cases and controls from the Genetic Epidemiology of CLL (GEC) Consortium, a cohort of families with ≥2 members with CLL. In the CLL families we also reported an association between the PRS and MBL risk, where 93% of MBLs were low-count MBL. Here we evaluate the PRS in an independent sample ascertained from the Mayo Clinic Biobank. Methods The Mayo Clinic Biobank is a large-scale bio-repository of adult patients assembled to provide a wide array of health-related research studies. Biobank participants (N=2530) were screened for MBL using a highly-sensitive, 8-color (CD38, CD45, Kappa, Lambda, CD19, CD23, CD5 and CD20) flow-cytometry assay on stored cryopreserved peripheral blood mononucleotide cells. Low-count and high-count MBL were defined as those individuals who had <85% and ≥85 clonal B-cells out of total B-cells, respectively. Individuals without MBL ("controls") were frequency matched to MBLs based on age and sex, after excluding non-Caucasian and non-interpretable flow results. Participants were genotyped using the Illumina OmniExpress array. Standard genotyping quality-control metrics were applied. We computed the PRS as previously published and categorized it by quintiles based on values previously used with InterLymph controls. The middle quintile served as the reference category. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CI), adjusting for age at consent, sex, and socioeconomic status. In addition, we compared the median PRS by low-count MBL and high count MBL using the Mann-Whitney U test. Results We identified 276 MBLs overall and 2109 controls; 97% (N=267) of MBLs had low-count MBL and only 3% (N=9) had high-count MBL. We then selected 844 controls frequency matched to the MBL cases on age and sex. Family history of leukemia/lymphoma was 11.3% among MBLs overall and 8.8% among controls. The median PRS was 7.88 and 7.46 (Figure) among MBLs overall and controls, respectively. The continuous PRS had a 1.75-fold increased risk for MBL overall (CI:1.5-2.1, P=2.65x10-12). Compared to the middle quintile, the highest quintile had 2.2-fold increased risk for MBL overall (CI:1.5-3.3, P=1.46x10-4) and the lowest quintile had 0.6-fold decreased risk (CI:0.4-0.96, P=0.03). The median PRS for low-count and high count MBL were 7.86 and 8.04, respectively. The continuous PRS had a 1.75-fold increased risk for low-count MBL (CI:1.5-2.1, P=4.81x10-12) and a 1.89-fold increased risk for high-count MBL (CI:0.8-4.2, P=0.13), however, the effect is not statistically significant between high-count and low-count MBL (P=0.89). Conclusion In this independent sample, we validated our previous findings that the CLL PRS is associated with MBL risk. Although the sample size of high-count MBL was limited (N=9), there is evidence of a weak trend towards a higher PRS compared to low-count MBL and controls Larger sample size of high-count MBL is warranted in order to stratify MBL risk by low-count and high-count MBL. These results may help identify individuals at higher risk of MBL including low-count and high-count MBL, beyond the risk associated with age and family history of CLL. Figure: Polygenic risk score distribution by control and MBL status Figure. Figure. Disclosures Parikh: Janssen: Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria; Abbvie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; MorphoSys: Research Funding. Cerhan:Nanostring: Research Funding; Celgene: Research Funding; Jannsen: Other: Scientific Advisory Board. Kay:Janssen: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees. Shanafelt:Genentech: Research Funding; Pharmacyclics: Research Funding; GlaxoSmithKline: Research Funding; Jansen: Research Funding.

Abstract Abstract 4607 Background: Extramedullary Chronic Lymphocytic Leukemia (EM-CLL) is reported in the literature as case reports and series. The prognosis, patient characteristics, and treatment approaches to EM-CLL have not been fully analyzed in a comprehensive fashion. We therefore conducted a systematic review to better understand EM-CLL and how it might affect patients' clinical course and overall survival. Methods: A comprehensive PubMed search for English-language articles published between 1975 and 2010 in peer-reviewed journals was performed. EM-CLL was defined as CLL identified pathologically in these reports outside the bone marrow. Search terms included “EM-CLL, CLL outside the bone marrow, and CLL with each system [central nervous system (CNS), genitourinary (GU/GYN), gastrointestinal (GI), cardiac, pulmonary, head and neck (H+N), skin, and vascular]. Data regarding location, sex, age at diagnosis, systemic CLL disease setting (relapsed vs. initial diagnosis), laboratory studies/prognostic factors (when available), treatment for CLL (yes or no), use of chemotherapy (yes or no), use of radiation (yes or no), use of rituximab (R), use of purine analogues, outcome (alive or deceased), and follow-up were collected. A z-test was used for assessing proportion differences for gender, stage (Rai 0, 1, 2 vs. Rai 3, 4), and chemotherapy (yes or no). Univariate analyses were performed via the Chi-square test. A backward stepwise logistic regression analysis was performed to identify whether disease location, disease setting, age, and sex influence overall survival (OS). No other multivariate analyses were performed due to large percent of missing data for different variables of interest. A two-tailed P level of 0.05 was considered statistically significant in all analyses; which were performed using SPSS for windows, version 19.0 (SPSS Inc.) and StarStat (DataStar, Inc.). Results: A total of 192 cases were identified [63 (33%) skin, 51 (27%) CNS, 26 (14%) GI, 20 (10%) GU/GYN, 10 (5%) lung, 10 (5%) ocular, 6 (3%) heart, 5 (3%) H+N, and 1(0.5%) vascular]. Median age at detection of EM-CLL was 62 (range, 25–89); significantly more men were diagnosed with EM-CLL versus women (61% vs. 35%; z = 3.51, P <.001); more patients were at early stage (Rai 0, 1, 2) versus advanced (Rai 3 and 4) at time of EM-CLL but this difference was not statistically significant (22% vs. 18%; z = .43, P =.665). More patients with EM-CLL were treated with chemotherapy for their underlying systemic CLL than not (65% vs. 15%, z = 6.25, P <.001); very few patients received radiotherapy which was delivered for their EM-CLL (n=35; 18%) but treatment information was missing from approximately 20% of cases. Our analysis showed that there was no significant difference with regard to number of patients treated with chemotherapy before and after the contemporary chemoimmunotherapy era (defined here as before and after the year 2000) (87% vs. 78%, p =.171). As far as systemic therapy for CLL, 12% of pts received R and 14% received purine analogues. Tissue sites such as CNS (45%), ocular (33%), H+N (25%), and skin (19%) were significantly more likely to receive XRT (p <.001) but no significant differences between the sites were reported for chemotherapy (p =.106), R (p =.237), and purine analogues (p =.090) usage. OS data was missing in 56 cases (29%), 79 were alive (41%), and 54 (28%) were dead at the time of case reporting. Backward stepwise logistic regression analysis, which included data for 102 (53%) patients showed that EM-CLL detected in patients with systemic relapse had worse OS compared to those with EM-CLL at time of initial CLL diagnosis (p =.027), while no significant effect on OS was found for tissue site (p =.085), age (above or below 70, p =.796), and sex (p =.791). All other variables were not significant. Conclusions: To our knowledge, this analysis represents the largest collection of EM-CLL series examined comprehensively. EM-CLL is not an uncommon presentation in the spectrum of CLL/SLL with skin and CNS being the most commonly affected organs (33% and 27% respectively). Patients who develop EM-CLL in the relapsed setting have significantly worse OS compared to those who manifest EM-CLL at the time of initial diagnosis. We propose that this subset of CLL needs a prospective and robust accumulation of prognostic and clinical data as it will be critical in defining how extramedullary presentation affects the biology and natural course of CLL. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: B-cell non-Hodgkin lymphomas (NHL) are common lymphoid malignancies in which malignant B-cells arrested at various stages of differentiation proliferate within lymph nodes and occasionally other tissues. The microenvironment that supports the growth and survival of NHL B cells consists of a complex network of immune cells and cytokines and its specific composition has been shown to have significant clinical implications. The intratumoral immune cells include effector and regulatory T (Treg) lymphocytes that are more than simple residual elements from the normal lymph node structure. We previously explored whether the extent of T cell infiltration played a role in the clinical outcome of patients with B-cell NHL and found that an increased percentage of CD4+ T cells in the diagnostic biopsy of lymphoma patients significantly correlated with an improved 5-year overall survival. We have also shown that intratumoral Treg cells significantly suppress the anti-tumor response. Based on the fact that intratumoral T-cells are important in B-cell NHL, we evaluated whether genetic variation in genes that regulate the T-cell response may be associated with lymphoma risk. Methods: We genotyped 257 single nucleotide polymorphisms (SNPs) from 50 candidate genes related to T-cell differentiation and function in a clinic-based study of 441 Caucasian NHL cases and 475 frequency matched Caucasian controls seen at the Mayo Clinic from 2002–2005. Tagging and nsSNPs were selected from HapMap. The most prevalent homozygous genotype was used as the reference group and each SNP was modeled individually as having a log-additive effect, expressed as ordinal odds ratios (OR) per variant allele and 95% confidence intervals, in an age- and sex-adjusted logistic regression analysis. We also evaluated the consistency of the findings for the most common types of B-cell NHL - diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and CLL/SLL. For gene-level analyses, we used principal components (PC) analysis using all SNPs from a gene; those PCs that explained > 90% of the variability were then modeled in a logistic regression analysis and significance was determined using a likelihood ratio test. We also evaluated the association of haplotypes from each gene with risk of NHL using the score test implemented from HAPLO.SCORE. Results. The mean age at diagnosis was 60.1 years for cases and 58% were male; among controls, the mean age at enrollment was 61.7 years and 55% were men. In the PC gene analyses, PRF1 (perforin gene - involved in cytotoxicity; p=0.004), CD276 (B7-H3 gene - involved in co-stimulation; p=0.01), TBX21 (T-bet gene – regulates Th1 cell development; p=0.02), and IL6 (p=0.02) were significant at p<0.05; haplotype analysis showed similar results, with the addition of CARD15 (NOD2 gene – regulates Th1 responses; p=0.02). There were 2 SNPs in PRF1, and both the intronic SNP rs3758562 (OR=1.38; 1.13–1.69) and the synonymous coding SNP rs885821 (OR=0.80; 0.63–1.02) were associated with NHL risk overall and for each subtype. There were 2 SNPs in CD276, and both the intronic SNP rs7176654 (OR=1.29; 1.07–1.56) and the mrna-utr SNP rs3816661 (OR=0.82; 0.68–0.99) were associated with NHL risk overall and with the CLL/SLL and follicular NHL subtypes specifically. There were 2 SNPs in TBX21, and only the mrna-utr SNP rs7502875 (OR=0.73; 0.59–0.92) was associated with NHL risk overall and for each subtype. There were 11 SNPs in IL6, and the intronic SNP rs2069835 (OR=1.88; 1.24–2.84) and the locus-region SNP rs2069824 (OR=1.73; 1.20–2.50) were each associated with NHL risk overall and each subtype. Finally, there were 9 SNPs in CARD15, with only the nonsynonymous coding SNP rs5743291 (OR=1.43; 1.02–1.98) being associated with overall NHL risk, and risk was specific to FL. Conclusions. Genetic variation in several genes that play critical roles in T-cell maturation and function was associated with lymphoma risk. These genes appeared to be associated with the differentiation and function of effector T-cells particularly Th1 and Th17 cells. These results provide potentially important insights into the role of T-cells in lymphomagenesis.

Abstract Background: Reactive oxygen species cause DNA damage and altered immunologic responses, and have been linked to the development of NHL. Diets rich in fruits and vegetables are excellent sources of antioxidants, and vitamins C, E, polyphenols, and carotenoids, along with selected micronutrients such as zinc are thought to be responsible for most of the antioxidant activity in foods. We evaluated the hypothesis that vegetables, fruits and nutrients involved in antioxidant activity would protect against developing NHL. In a secondary analysis, we also assessed heterogeneity of this hypothesis for the most common subtypes of NHL: chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), follicular lymphoma, and diffuse large B cell lymphoma (DLBCL). Methods: We evaluated dietary antioxidant intake and NHL risk in a clinic-based study of 416 newly diagnosed NHL cases and 926 frequency-matched controls enrolled at the Mayo Clinic from 2002–2007. Usual diet two years before diagnosis/enrollment was assessed using a self-administered, 128-item food frequency questionnaire. Dietary intake of antioxidants was estimated using the Food Processor SQL system, further supplemented with data from US Department of Agriculture nutrient databases. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI), adjusted for age, sex, residence, and total energy. NHL subtypes were centrally reviewed, and subtype-specific risks were estimated using polychotomous logistic regression. Results: The mean age at diagnosis was 60.8 years for cases and 57% were male; for controls, the mean age at enrollment was 60.8 years and 54% were men. NHL risk was inversely associated with intake of total vegetables (OR for highest compared to lowest quartile, 0.46; 95% CI 0.32–0.68; p-trend<0.001), and specifically green leafy (OR=0.54; 95% CI 0.39–0.76; p-trend<0.001) and cruciferous (OR=0.62; 95% CI 0.43–0.88; p-trend=0.02) vegetables, but not legumes or red/yellow/orange vegetables. There was no association with total fruit intake or intake of citrus fruits in particular. When modeled together, the association for green leafy vegetables was unchanged while the association for cruciferous vegetables attenuated (OR=0.75; 95% CI 0.50–1.13; p-trend=0.3). Higher intake of total vitamin A (OR=0.60; 95% CI 0.41–0.88; p-trend<0.001) and vitamin E (OR=0.53; 95% CI 0.34–0.82; p-trend<0.001), but not vitamin C, were associated with lower NHL risk. For vitamin A, there was no association with preformed Vitamin A, but there was an inverse association with beta-carotene (OR=0.56; 95% CI 0.39–0.81; p-trend<0.001); only weak inverse associations were observed for other carotenoids (lutein/zeaxanthin, lycopene, and cryptoxanthin). When modeled together, the inverse association for vitamin E was unchanged while the association for beta-carotene attenuated. For micronutrients, there were inverse associations for manganese (OR=0.60; 95% CI 0.40–0.90; p-trend=0.02), selenium (OR=0.47; 95% CI 0.27–0.80; p-trend=0.01), and zinc (OR=0.46; 95% CI 0.27–0.80; p-trend<0.001) but not copper; when modeled simultaneously, both manganese (p-trend=0.03) and zinc (p-trend=0.02) remained significantly and inversely associated with NHL risk. Further adjustment for education, family history of NHL, smoking, alcohol use, and body mass index did not alter these results. There was no NHL subtype heterogeneity for the associations with total vegetables, green leafy vegetables or vitamin E, while inverse associations were not observed for manganese and follicular lymphoma or zinc and CLL/SLL. Conclusion: Higher intakes of vegetables, particularly green leafy vegetables, vitamin E, manganese, and zinc were associated with lower risk of NHL. These finding extend a growing literature from case-control and cohort studies that support a protective role of foods and nutrients that function in antioxidant related pathways against development of NHL, and therefore may represent one of the few known modifiable risk factors for this cancer.

Abstract Abstract 2835 Background: Extrinsic growth and survival signals provided by nonneoplastic cells present within the tumor microenvironment promote the growth and survival of CLL cells. For example, bone marrow stromal cells, blood-derived “nurse-like” cells and follicular dendritic cells have been shown to promote the survival of CLL cells via the provision of both soluble and cell-contact dependent factors. More recently, monocytes were convincingly shown to support the survival of CLL cells during in vitro culture, and many of the factors (e.g. BLyS/BAFF, SDF-1, CD14) previously implicated in supporting the growth and survival of CLL cells are produced by monocytes. To explore the potential clinical implications of these in vitro findings, we evaluated the relationship between the absolute monocyte count (AMC) at diagnosis and disease progression in a well defined cohort of CLL patients. We hypothesized that the presence of a relative monocytosis at presentation in patients newly diagnosed with CLL may create a nurturing environment for CLL cells and be associated with more rapid disease progression. Methods: Previously untreated patients diagnosed with CLL/SLL within 12 months of presentation to the Mayo Clinic (from 1/1/2000-8/31/2010) were identified (n=1396). The AMC was obtained from routine complete blood counts (CBC) with automated or manual differentials that were performed within 3 months of diagnosis (n=947). The primary study objective was to determine whether the AMC is associated with time to first treatment (TTFT) in CLL. The secondary objective was to determine whether the AMC had independent prognostic value after adjusting for CD38/CD49d/Zap-70 expression, IGHV gene mutation status, and cytogenetic (11q-, 17p-) findings by FISH analysis. Results: The median age was 66 years and the median AMC was 550/μL (380–812/ μL, 1st-3rd quartile) at diagnosis (normal range: 300–900/μL). No significant difference in the median AMC was observed by age, gender; CD38, CD49d, or Zap-70 expression; IGHV gene mutation status or cytogenetic findings. Patients were followed for a median of 3.2 years (range: 0–10.3), with disease progression requiring the initiation of treatment observed in 268 (28%) patients. On multivariate analysis using a Cox proportional hazards model which incorporated age, gender and Rai stage, the AMC (as a continuous variable) was associated with TTFT with a hazard ratio (HR) of 1.099 (per unit change; 95% CI, 1.003–1.205; p=0.04). The optimal cutpoint for the association between AMC and TTFT was determined to be ≥1, 170/μL, a threshold that remained an independently significant predictor of TTFT after adjusting for age, gender and Rai stage with a HR of 5.1 (95% CI, 2.56–10.10, p<0.0001). The median TTFT was 1.0 year for patients with an AMC ≥1, 170/μL and 7.4 years for those with an AMC <1, 170/μL (p<0.0001). In order to evaluate whether the AMC had independent prognostic value after adjusting for other prognostic biomarkers, CD38, CD49d, Zap-70, IGHV gene mutation status and cytogenetic findings (11q- or 17p-), were individually incorporated into the multivariate analysis. In each case, the AMC remained an independent predictor of TTFT, with HRs ranging from 4.31 to 5.43 (p<0.0001 for all analyses). Conclusions: The AMC at the time of diagnosis as measured by a routine CBC is associated with accelerated disease progression in CLL/SLL independent of other prognostic biomarkers. These results suggest that the in vitro observation that nonneoplastic cells present in the tumor microenvironment promote CLL cell survival may have direct clinical implications for the prognostic evaluation of CLL patients and further substantiate the pathogenic role of monocytic cells in CLL. Disclosures: No relevant conflicts of interest to declare.