Ding, Wei

Abstract BACKGROUND: Consistent with the advanced age at diagnosis (median age ~70 years), most patients with CLL have co-existent health problems. These co-morbidities influence the ability of many CLL patients to tolerate aggressive chemotherapy-based treatment and can also contribute to treatment-related side effects. The recent development of novel signaling inhibitors, particularly the Bruton's tyrosine kinase inhibitor ibrutinib, has been a major treatment advance for patients with CLL. While these agents generally have favorable toxicity profiles relative to standard chemotherapy-based treatments, they are chronic therapies which patients typically stay on for an extended period. Preliminary data suggests ibrutinib may be associated with an increased risk of atrial fibrillation (Afib). In one randomized trial comparing ibrutinib to ofatumumab in patient with relapsed CLL, incident grade 3+ Afib occurred in 3% of ibrutinib treated patients compared to 0% of ofatumumab treated patients (NEJM 371:213). Despite these observations, the baseline frequency of Afib in patients with CLL is not well described - particularly incident atrial fibrillation acquired during the course of the disease. METHODS: We used the Mayo Clinic CLL database to evaluate the prevalence of Afib at the time of CLL diagnosis as well as the incidence of Afib during follow-up. All patients with a new diagnosis of CLL after January 1995 who were seen at Mayo within 12 months of diagnosis were included in the analysis. Afib was identified by chart review and by billing search using ICD9 codes. Data on co-morbid conditions associated with risk of Afib was also abstracted (e.g. hypertension, coronary artery disease [CAD], valvular heart disease, cardiomyopathy, diabetes mellitus, pulmonary disease). RESULTS: A total of 2444 patients with newly diagnosed and previously untreated CLL were seen at Mayo Clinic within 12 months of diagnosis between 1/1995 and 4/2015.Median age at diagnosis was 65 years and 1626 (66.5%) patients were men. A history of Afib was present at the time of CLL diagnosis in 148 (6.1%) patients. Four additional patients had Afib documented in the record but the precise date of onset (e.g. prior to or after CLL diagnosis date) could not be determined. Age, male sex and history of CAD, valvular heart disease, cardiomyopathy, hypertension, and diabetes were associated with a greater likelihood of having a history of Afib at the time of CLL diagnosis (all p<0.01). Among the 2292 patients without a history of Afib at CLL diagnosis, 139 (6.1%) had incident Afib during the course of follow-up for their CLL. The incidence of Afib among patients without a history of Afib at diagnosis was approximately 1%/year (Figure 1A). Considering both Afib present at the time of CLL diagnosis or acquired during the course of the disease, 291 (11.9%) of the 2444 patients in this cohort experienced Afib (median follow-up: 59 months). Among patients without Afib at the time of CLL diagnosis, the following characteristics at the time of CLL diagnosis were associated with an increased risk of incident Afib on multivariate analysis: older age (age 65-74 HR=2.4, p<0.001; age ≥75 HR=3.6, p<0.001), male sex (HR=1.8, p=0.004); valvular heart disease (HR=2.4, p=0.007), and hypertension (HR=1.5; p=0.02). A predictive model for acquired Afib was subsequently constructed based on the independent factors in the Cox regression model. An individual weighted risk score was assigned to each independent factor based on the regression coefficients of the HRs. The Afib risk score (range 0-7) was defined as the sum of the scores of these independent factors. The risk of incident Afib among patients with risk scores of 0-1, 2-3, 4, and 5+ is shown in Figure 1B. Rates for these 4 groups were significantly different (p<0.001), with the 10-year Afib rates (95% C.I.) for those with a score of 0-1, 2-3, 4, and 5+: 4% (2-6%), 9% (6-13%), 17% (11-23%), and 33% (20-43%), respectively. CONCLUSIONS: A history of Afib is present in approximately 1 out of every 16 patients with newly diagnosed CLL. Among patients without Afib at diagnosis, the incidence rate of Afib is ~1%/year. The risk of incident Afib in newly diagnosed CLL patients can be predicted based on age, sex, and co-morbid health conditions present at diagnosis. These data provide context to help interpret data on the frequency of Afib in CLL patients treated with ibrutinib and other novel agents. Disclosures Shanafelt: Janssen: Research Funding; Polyphenon E Int'l: Research Funding; Glaxo-Smith_Kline: Research Funding; Cephalon: Research Funding; Genentech: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Pharmactckucs: Research Funding. Ding:Merek: Research Funding. Kay:Tolero Pharm: Research Funding; Hospira: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Introduction: The Food and Drug Administration (FDA) approved ibrutinib in February 2014 based on results from a pivotal phase 2 clinical trial that enrolled 85 patients with relapsed/refractory CLL. A subsequent phase 3 trial confirmed the superior progression-free survival (PFS) and overall survival (OS) of ibrutinib compared to ofatumumab in 391 CLL patients. However, there is no information on the efficacy and safety of ibrutinib in CLL patients treated outside the context of clinical trials. Additionally, it is unclear if the reasons for discontinuation of ibrutinib differ in routine clinical practice from those described in patients treated on clinical trials. We conducted a retrospective study to evaluate these aspects in a large cohort of CLL patients treated with ibrutinib off-protocol. Methods: After IRB approval, CLL patients seen at Mayo Clinic, Rochester, MN, and treated with commercial ibrutinib from November 2013 through July 2015 were evaluated. The baseline characteristics, time to therapy discontinuation, reasons for discontinuation and survival following discontinuation were abstracted. Results: One hundred thirty-five patients with CLL were treated during the study interval; 124 received ibrutinib for relapsed/refractory CLL and 11 received ibrutinib for treatment-naïve CLL with TP53 disruption (either del17p on FISH or TP53 mutation). Patients with relapsed/refractory CLL (n=124) Patients were high-risk, with a median of 3 prior therapies (range, 1-15), 81% had unmutated IGHV, and 38% had either del11q or del17p on FISH testing. After a median follow-up of 6.4 months, 101 remain on ibrutinib therapy. The estimated proportion of patients continuing ibrutinib at 6 months was 84% (95% CI: 77-92%) and at 12 months was 70% (95% CI: 59-83%). Of the 23 who discontinued ibrutinib therapy, 8 discontinued for progressive disease (2 progressive CLL; 6 Richter's transformation). The remaining 15 discontinued therapy for reasons other than progression, including: infection (n=3), bleeding (n=3), diarrhea (n=1), atrial fibrillation (n=1), rash (n=1), immune thrombocytopenia (n=1), renal dysfunction (n=1), severe edema (n=1), MDS (n=1) and physician preference (n=2). Table 1 shows the reasons for discontinuation of ibrutinib in patients treated on clinical trials (Maddocks, JAMA Oncology, 2015) compared to the current cohort of patients. The estimated cumulative incidence of discontinuation of ibrutinib therapy due to CLL progression/Richter's transformation at 6 and 12 months was 9% (95% CI: 4-17%) and 12% (95% CI: 5-23%), respectively. The estimated cumulative incidence of ibrutinib discontinuation due to reasons other than progression at 6 and 12 months was 10% (95% CI: 5-17%) and 22% (12-34%), respectively (Figure). The median survival after discontinuation of ibrutinib for patients who had CLL progression was 3.5 months, not reached in patients who developed Richter's transformation and not reached in those patients who discontinued ibrutinib due to reasons other than progression. Patients with treatment-naïve CLL (n=11) All patients had evidence of TP53 disruption (9 had del17p, 3 had TP53 mutation, and 1 had both). After a median follow-up of 2.8 months, no patient has had progression of CLL, and 2 patients have discontinued ibrutinib therapy for reasons other than CLL progression (atrial fibrillation, n=2). The estimated proportion of patients continuing ibrutinib at 6-months was 71% (95% CI: 45-100%). All 11 are still alive, and no patient has undergone allogeneic stem cell transplantation. Conclusion: This is the first study that describes the outcomes of a large cohort of CLL patients treated with ibrutinib outside the context of clinical trials. Patients treated in routine practice appear more likely to discontinue ibrutinib for reasons other than progression of disease, compared to those participating in clinical trials. Our results confirm the poor survival of CLL patients who progress on ibrutinib. Table 1. Comparative analysis of reasons for discontinuation of ibrutinib in patients with relapsed/refractory CLL: Characteristic Current Study (%) Maddocks (JAMA Oncology 2015) (%) No. of patients 124 308 Median follow-up (months) 6.4 20 Reasons for Discontinuation Progression of disease CLL 2 (2) 13 (4) Richter's transformation 6 (5) 15 (5) Non-progression of disease Infection 3 (2) 28 (9) Other 12 (10) 17 (5) Figure 1. Figure 1. Disclosures Ding: Merek: Research Funding. Kay:Celgene: 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, Research Funding; Hospira: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Tolero Pharm: Research Funding. Shanafelt:Cephalon: Research Funding; Celgene: Research Funding; Glaxo-Smith_Kline: Research Funding; Polyphenon E Int'l: Research Funding; Hospira: Research Funding; Janssen: Research Funding; Pharmactckucs: Research Funding; Genentech: Research Funding.

Abstract Background: PRCA is characterized by severe normochromic normocytic anemia, reticulocytopenia, and markedly reduced bone marrow erythroid precursors with intact leukocytic and megakaryocytic lineages. There is limited information about the prevalence and outcomes of PRCA in CLL, with the vast majority of information derived from case reports and small series comprising <10 patients. Here, we describe the clinical features, therapy, and outcomes of CLL patients with PRCA seen at our institution. Methods: The Mayo Clinic CLL Database includes all patients with a diagnosis of CLL evaluated at Mayo Clinic Rochester, MN between January 1995 and December 2014. We identified patients diagnosed with PRCA per the following diagnostic criteria: those who presented with normocytic anemia, had decreased erythroid precursors on bone marrow examination, and reticulocytopenia that could not be explained by any other cause besides PRCA. The baseline demographics, clinical characteristics, therapy, and outcomes were abstracted from the electronic medical records. We generated descriptive statistics and calculated overall survival (OS) from diagnosis date (PRCA, autoimmune cytopenia [AID], or CLL) to last known alive or death date. OS was plotted using Kaplan Meier curves and compared between groups using log-rank statistic. The Mayo Clinic IRB approved this study. Results: Of the 3945 CLL patients seen during the study interval, we identified 30 patients who met the diagnostic criteria of PRCA as described in the Methods section. The baseline characteristics, etiology and therapy for PRCA are shown in Table 1. The median time to PRCA from CLL diagnosis was 4.5 years (range-0.1-14 years). Of the 13 patients with IGHV results available, 12 (92%) were IGHV unmutated. Twenty-one (70%) were male and their median age at PRCA diagnosis was 67 years (range 40-81 years). Parvovirus testing was positive in 6 of 24 (25%) patients who were tested; 3 of these patients were treated with IVIG, 2 were treated with prednisone and IVIg, and 1 was treated with prednisone and rituximab. Eight patients (27%) had both PRCA and autoimmune hemolytic anemia (AIHA), and 1 patient (3%) had concomitant PRCA and immune thrombocytopenia (ITP). Of the 27 patients for whom we have treatment data, 10 required only one treatment regimen and 17 required 2-6 treatment regimens, with two patients requiring splenectomy for concomitant AIHA. The median survival of CLL patients after a diagnosis of PRCA was 4.6 years (Figure 1). There was no difference in survival between PRCA cases with and without parvovirus (p=0.92). Compared to newly diagnosed CLL Rai stage III/IV patients, there was no difference in OS (p=0.53). There was no statistically significant difference in survival from an AID cytopenia diagnosis when comparing PRCA, ITP, AIHA, and Evans syndrome (Figure 1; median 5 years for PRCA and 6 years for other groups; p=0.17). Conclusion: PRCA is a rare complication in CLL, occurring in <1% CLL patients seen at our institution over the past 20 years. Parvovirus was the etiologic factor in ~25% of patients and did not influence outcomes. There appears to be no significant difference in outcomes of PRCA patients compared to patients with other AID in CLL. Table 1. Patient Characteristics Characteristic N [range] or (%) Number of patients 30 Males 21 (70) IGHV status* · Unmutated · Mutated 12 (92) 1 (8) FISH results at CLL diagnosis* · 17p- · 11q- · Trisomy 12 · 13q- · Negative 0 (0) 1 (10) 3 (30) 3 (30) 3 (30) At PRCA Diagnosis Median age 67 [40 - 81] Median hemoglobin (gm/dL)* [normal range 12-15.5 gm/dL] 8.2 [3.5 - 10.8] Median absolute reticulocyte count (x 109/L)* [normal range: 38 - 113 x 109/L] 3.5 [0.0 - 25.3] Patients treated for CLL prior to PRCA diagnosis 25 (83) Etiology of PRCA Parvovirus (n = 24) 6 (25) Therapy-related: · Fludarabine · Alemtuzumab/rituximab · Pentostatin/cyclophosphamide/rituximab 3 (10) 1 (3) 1 (3) Autoimmune (neither therapy nor parvovirus related) 19 (63) Initial Therapy of Non-Parvovirus Related PRCA Steroids alone 2 (8) Steroids and Rituximab 3 (13) Steroids in combination with: · IVIG, Chlorambucil · Cyclosporine · Rituximab, IVIg · IVIg, splenectomy 1 (4) 2 (8) 1 (4) 1 (4) Monoclonal Ab alone · Alemtuzumab · Rituximab 1 (4) 4 (17) Cyclosporine 1 (4) Cyclophosphamide 2 (8) RCP (Rituxan, Cyclophosphamide, and prednisone) 2 (8) IVIg 1 (4) Not available 3 (13) *Not available for all patients Figure 1. Figure 1. Disclosures Ding: Merck: Research Funding. Kay:Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; Tolero Pharma: Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding. Shanafelt:Cephalon: Research Funding; Hospira: Research Funding; Glaxo-Smith-Kline: Research Funding; Genentech: Research Funding; Jannsen: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding; Pharmacyclics: Research Funding.

Abstract Background Severe cytopenias in CLL are typically associated with bone marrow failure due to massive infiltration of the bone marrow by leukemic cells and negatively impact patient morbidity/mortality. Although near complete marrow replacement by CLL is typically observed in patients whose degree of cytopenia meet criteria for advanced Rai stage disease (Hg<11g/dL; platelet <100 x10^9/L), profound variability in the degree of cytopenia and the extent of marrow infiltration exists, and the relationship between these dimensions is not well characterized. Methods We used the Mayo Clinic CLL database to identify all previously untreated CLL/SLL patients who underwent bone marrow biopsies. CLL patients known to have autoimmune-based cytopenias were excluded from this study. Hemoglobin, platelets, absolute neutrophil count (ANC), absolute lymphocyte count (ALC), and absolute monocyte (AMC) at the time of bone marrow biopsy were collected. Characteristics from bone marrow biopsy including marrow cellularity, % CLL involvement, CLL leukemic index (calculated as % cellularity times % CLL), and non-CLL leukemic index (calculated as % cellularity times (1-% CLL)) were also collected. Bone marrow cellularity and % CLL involvement were recorded in the Mayo Clinic CLL database based on clinical estimates made by Mayo hematopathologists. Clinical characteristics and CLL prognostic factors (e.g., Rai stage, CLL FISH, IGHV, ZAP-70, CD38 and CD49d) were also obtained from the database. Age- and sex-adjusted Pearson correlations between the bone marrow measurements and hemoglobin and platelet levels were computed, and scatterplots were created. Results A total of 695 untreated CLL patients diagnosed between 1972 and 2015 who had a CBC test at the time of bone marrow biopsy performed at Mayo Clinic were identified. Median age at diagnosis was 61 years, and 487 (70%) patients were men. Mean time from CLL diagnosis to bone marrow biopsy was 2.2 years. At the time bone marrow biopsy was performed, 20% of patients had advanced stage disease (Rai III/IV) disease, while 44% and 36% had intermediate (Rai I/II) and early stage (Rai 0), respectively. With respect to prognostic parameters, 53% had unmutated IGHV and 20% had high risk CLL FISH (11q- and 17p-). The distribution of other prognostic factors included 43% CD49d+, 35% CD38+, and 42% ZAP-70+ CLL diseases. Median peripheral blood counts were: hemoglobin 13g/dL, platelet 167,000/mL, ALC 26,600/mL, ANC 4100/mL, AMC 700/mL. The median bone marrow cellularity and percent CLL involvement were 70% and 70%, respectively. The median CLL leukemic index was 42%, and median non-CLL leukemic index was 21%. Pearson correlation analysis of bone marrow measurements with peripheral blood hemoglobin found the strongest correlation with the CLL leukemic index (r= -0.49, p<0.001) (Figure), followed by the % marrow CLL involvement (r= -0.45, p<0.001), cellularity (r= -0.40, p<0.001), and non-CLL leukemic index (r= 0.37, p<0.001). Pearson correlation analysis of the bone marrow measurements with platelet count also found the strongest correlation with the CLL leukemic index (r= -0.39, p<0.001), followed by % marrow CLL involvement (r= -0.38, p<0.001), non-CLL leukemic index (r= 0.35, p<0.001), and cellularity (r= -0.28, p<0.001). The peripheral blood ANC levels did not correlate with the four bone marrow measurements. Age- and sex-adjusted Pearson correlations between the bone marrow measurements and hemoglobin and platelet levels were similar to the above unadjusted results. Conclusion To our knowledge, this is the first study to examine the relationship between peripheral blood counts and the extent of bone marrow infiltration in patients with CLL. Although the bone marrow leukemic index had the strongest correlation with peripheral blood Hg and platelet counts, the correlation was modest with an r value of -0.49. These findings suggest that the extent of infiltration of the bone marrow by CLL cells only partially explains of the anemia and thrombocytopenia observed in CLL, indicating other biologic interactions between CLL B-cells and hematopoietic cells contribute to anemia and thrombocytopenia in these patients. More research is needed to determine the nature of these interactions. Disclosures Ding: Merek: Research Funding. Kay:Genentech: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; Celgene: 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, Research Funding; Tolero Pharm: Research Funding. Shanafelt:genentech: Research Funding; Glaxo-Smith-knine: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; Hospira: Research Funding; Polyphenon E Int'l: Research Funding.

Abstract Abstract 2414 Background: Mesenchymal stromal cells (MSC) derived from normal subjects are known to have immunosuppressive capacity by virtue of inhibiting T- and B-cell activation. A novel subset of T cells, Th17, plays an important role in inflammation and autoimmunity. A recent report demonstrated that normal MSC ameliorates experimental autoimmune encephalomyelitis by inhibiting CD4+ Th17 cells in a chemokine ligand 2-dependent manner (J Immunol. 2009, 182: 5994). It remains unknown if MSC derived from leukemic or cancer patients play a role in Th17 cell differentiation. In particular this would be of interest to study in B-Chronic Lymphocytic Leukemia (CLL) where immunosuppression is evident even in early stage disease. Methods: MSC derived from bone marrow of CLL patients or normal subjects were expanded in vitro as previously described by us (Br J Haematol. 2009, 147:471). CD4+ cells positively selected from normal peripheral blood mononuclear cells were co-cultured with either CLL MSC or normal MSC at a ratio of 50:1 for 3 days with stimulation via CD3/CD28 beads, as well as interleukin-1β (IL-1β; 50 ng/ml). Then phorbol 12-myristate 13-acetate (50 ng/ml) and ionomycin (500 ng/ml) were introduced into the co-culture for 5 hrs in the presence of brefeldin A. Subsequently, cells were stained with CD4-phycoerythrin (PE) and IL-17-Alexa647 using intracellular flow to analyze the percent expression of IL-17 in CD4 + cells. Cytokine production from both CLL MSC and normal MSC as secreted into culture medium (CM) were tested using a commercial multiplex cytokine array (Invitrogen, CA). This array measures the level of 30 different cytokines. Results: Positively selected CD4+ cells from peripheral blood of normal donors contain minimal percentages of Th17 cells (range: 0.48–0.71%). IL-1β stimulation induced increased IL-17 expression (range: 1.05–1.12%). Co-culture of CLL MSC with CD4+ cells induced significantly increased IL-17 expression in the CD4+ T cells (range: 1.16–1.32%). The promoting effect of CLL MSC on these Th17 cells appeared to be mediated by direct contact since the CM of CLL MSC was not able to induce increased IL-17 expression (mean = 0.66%) to a similar level as direct co-culture. When IL-1b was used to stimulate Th17 cell differentiation from CD4+ cells, CLL MSC were able to further promote the level of Th17 cell differentiation (range: 2.01–2.63%), indicating synergistic function for CLL MSC with IL-1β. This latter finding again appeared to be more pronounced for CLL MSC as normal MSC with IL-1β was not able to promote Th17 cell differentiation to a similar degree. To further investigate the mechanism of CLL MSC on Th17 cell differentiation, we assessed the cytokine production for resting CLL MSC and normal MSC compared to cytokine production of CLL and normal MSC stimulated with IL-17. The data from multiplex cytokine arrays revealed that the cytokine profiles were not different between resting CLL and normal MSC; however, when MSC were stimulated with IL-17, there were significant differences between CLL and normal MSC in terms of IL-6 and MCP-1 production (IL-6, CLL vs. normal, 957.9 ± 98 vs. 554.2 ± 92.3 pg/ml, p = 0.01; MCP-1, CLL vs. normal, 787.7 ± 166.9 vs. 330.2 ± 116.5 pg/ml, p = 0.04, n = 7). Since both IL-6 and MCP-1 have been demonstrated to play important roles in Th17 differentiation, we are conducting further studies to dissect the mechanism of CLL MSC in the promotion of Th17 cell differentiation. Conclusions: These results indicate that MSC derived from CLL patients promotes Th17 cell differentiation in vitro, which is in contrast to the previous published suppressive role of normal MSC on Th17 cell differentiation. Recent findings have indeed demonstrated that CLL patients do have high percentage of Th17 cells (Cancer Res. 2009. 69: 5922) when compared to other lymphoproliferative diseases. Given this data we believe that CLL MSC are intrinsically different from normal MSC in terms of immune regulation and cytokine production. This may occur as a result of the bi-directional activation that we found to be present between MSC and CLL leukemic cells (Br. J Haematol. 2009. 147:471). In total, our findings demonstrated that the dynamic interactions between the CLL leukemic cells and MSC appear to influence the Th 17 cell levels. This is of biological and clinical interest in that Th17 cells have the potential to regulate the immune environment to favor tumor proliferation and progression. Disclosures: No relevant conflicts of interest to declare.

Abstract Patients with CLL complicated by autoimmune diseases causing cytopenias (AID) are often considered to have clinically advanced disease (Rai stage III - IV, Binet C). With the use of automatic differential counts and flow cytometric immunophenotyping of peripheral blood, CLL is now most often diagnosed in asymptomatic patients with early stage disease. These changes in clinical practice could have an impact on clinical presentation and prognosis of CLL patients with AID. To more fully define AID complicating CLL, we conducted an observational study of a large cohort of CLL patients. Methods All 1737 patients with chronic B cell lymphoproliferative diseases seen in the Division of Hematology at Mayo Clinic Rochester from January 1, 1995 to December 30, 2004 were included. Lymphoid malignancies were classified using WHO and modified NC-WG 1996 criteria (CLL = 1649, “atypical” CLL = 4, leukemic phase of lymphoma = 9, chronic B cell lymphoproliferative disorders (not otherwise classified) = 75). Autoimmune hemolytic anemia (AIHA) was defined as a Hgb ≤ 10 g/dL with at least one appropriate marker of hemolysis (elevated indirect bilirubin, LDH, or reticulocyte count; or increased bone marrow erythropoiesis without bleeding) and evidence of an autoimmune mechanism (positive DAT, cold agglutinins), or at least 2 markers of hemolysis in absence of evidence of bleeding or hypersplenism. Immune thrombocytopenia (ITP) was defined as a platelet count of ≤100 x 109/L with normal/ increased bone marrow (BM) megakaryocytes or normal/increased absolute reticulocyte count. Pure red blood cell aplasia (PRBCA) was defined as a Hgb ≤ 10 g/dL, reticulocytopenia, and an isolated absence of BM erythrocyte precursors. Autoimmune granulocytopenia (AIG) was defined as sustained neutropenia (< 0.5 x 109/l) in the absence of chemotherapy for at least 8 weeks and with decreased/absent BM granulocyte precursors. Results Seventy four (4.5%) CLL patients had AID (78% male, median age at diagnosis 67 yr). The diagnosis of AID preceded CLL in 12% and was concomitant with the diagnosis of CLL in 15% of patients. Of the CLL patients with AID, 55% had AIHA, 47% ITP, 10% PRBCA and 4% AIG; 10% had coincident AIHA and ITP (Evans syndrome). Most AIHA (74%) patients presented with symptomatic anemia but 68% of the ITP patients were asymptomatic at diagnosis. Forty one patients (55%) developed AID prior to receiving any treatment for CLL. Only 9 of the 33 patients who developed AID after treatment for CLL had received purine analogues. Eighteen (24%) patients with CLL and AID died; the estimated median survival was 12.4 yr. Discussion In this CLL population with predominantly early stage disease at diagnosis (> 60% Rai stage 0), AID is clinically distinct from that previously reported in patients with more advanced disease. A higher proportion of patients had ITP which was usually asymptomatic. Most patients with AID had not previously required therapy for CLL. Purine analogue therapy did not appear to be a major cause of AID in this population. Overall survival was considerably more favorable than that previously reported with CLL induced bone marrow failure (Rai stage III-IV, Binet C). We conclude that the earlier diagnosis and subsequently longer follow up of patients with CLL has altered the clinical presentation and prognostic consequences of AID. A more detailed analysis of the correlation between novel prognostic risk factors and the risk of AID in CLL patients is planned.

Abstract Abstract 2902 Background: Although chronic lymphocytic leukemia (CLL) is a low grade B-cell malignancy, 2–8% of patients (pts) are reported to undergo transformation to diffuse large B-cell lymphoma (DLBCL; Richter's syndrome [RS]). Whether the risk of transformation is related to the underlying biology of CLL or is a consequence of treatment for CLL is uncertain. Also, the role of prognostic markers such as immunoglobulin heavy chain (IGHV) gene mutation status, ZAP-70 and CD38 expression, and genetic abnormalities detected by fluorescence in situ hybridization (FISH) in predicting the development of RS is not well defined. The available data on stem cell transplant (SCT) in pts with RS is based on retrospective case series of selected RS pts and is of uncertain relevance to the majority of CLL pts experiencing RS. Therefore, we conducted a cohort study of newly diagnosed CLL pts to explore the incidence and natural history of RS. Methods: The Mayo Clinic CLL database includes all consenting pts with a pathologic diagnosis of CLL. Information on date of diagnosis, treatment history, and disease-related complications is abstracted from clinical records on all pts and then maintained prospectively. We used this database to identify newly diagnosed pts with CLL from January 2000 through July 2011, who were seen at our institution within 12 months of diagnosis. Pts with biopsy-confirmed RS were included in this analysis. For pts referred from an outside institution, pathology review at Mayo Clinic was mandatory to be included in this study. The Mayo Clinic Institutional Review Board approved the study. Results: Between January 2000 and July 2011, 1641 pts with newly diagnosed CLL were seen at Mayo Clinic within 12 months of diagnosis, and this cohort had a median follow-up of 4.0 yrs (range, 0–12.3 yrs). Of these pts, 37 (2.3%) were diagnosed with RS. The median time to development of RS after a diagnosis of CLL was 1.8 yrs (range, 0–11.7 yrs). The incidence of RS at 2 and 5 yrs post CLL diagnosis were 1.3% and 2.1% respectively (Figure). Pts who developed RS had more advanced (Rai III/IV) stage disease (22% vs. 6%; p<0.001) and higher beta 2-microglobulin levels (median 3.1 mg/dL vs. 2.3 mg/dL; p=0.003) at diagnosis of their CLL compared to pts without RS. Pts who developed RS were also more likely to be positive for ZAP-70 (58% vs. 33%; p=0.03), CD49d (77% vs. 31%; p=0.0004), and CD38 (57% vs. 29%; p=0.001), have unmutated IGHV (76% vs. 44%; p=0.003) and have either del(11q22.3) or del(17p13) on FISH analysis (46% vs. 13%; p<0.0001). RS transformation occurred prior to treatment of CLL in 17 (46%) pts and after treatment of CLL in 20 pts (54%). Treatment for CLL was associated with an increased risk of RS (92% vs 34%; p<0.0001). The odds ratio (OR) of RS was increased for pts who received purine nucleoside analogues (OR=3.0; 95%CI=[1.6, 5.9]; p=0.001), alkylating agents (OR=2.5; 95% CI=[1.3, 4.9]; p=0.004), or both (OR=3.3; 95% CI=[1.7, 6.4]; p=0.0003) for treatment of their CLL. Median overall survival after development of RS was 2.1 yrs. Most pts (29/37, 78%) received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) therapy. Two (5%) pts underwent an autologous SCT and 5 (14%) underwent an allogeneic SCT. Additionally, 1 (3%) patient received an autologous SCT followed by an allogeneic SCT. By the end of the study period, 17 (46%) pts with RS had died. Conclusion: The overall rate of biopsy-proven RS in this large cohort of pts with newly diagnosed CLL was 2.3% (5 year incidence: 2.1%). Clinical characteristics (Rai stage III/IV) and biologic characteristics of the CLL B-cell (positive expression of ZAP-70, CD38 and CD49d; unmutated IGHV; and either del(11q22.3) or del(17p13) on FISH) at the time of diagnosis were associated with future risk of RS. Exposure to purine nucleoside analogues and/or alkylating agents for treatment of CLL was also associated with increased risk of RS. Disclosures: Zent: GlaxoSmithKline: Research Funding; Novartis: Research Funding; Genentech: Research Funding; Genzyme: Research Funding; Biothera: Research Funding. Shanafelt:Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

Abstract Background: CLL patients (pts) treated with novel targeted therapies continue to experience disease progression. Approximately 7-15% of relapsed CLL treated with ibrutinib or venetoclax developed Richter's syndrome (RS), an aggressive high grade lymphoma transformation. Standard chemotherapy has limited efficacy in RS. We hypothesized that checkpoint blockade would re-establish anti-tumor immune response in progressive CLL/RS and here we aim to update the clinical data and correlative analysis of MC1485: a phase 2 study of PD-1 blocking antibody pembrolizumab in relapsed/refractory CLL and RS. Methods: Relapsed/refractory CLL including RS enrolled in the CLL arm of MC1485 trial was reported here. The primary end point of this study is overall response rate (ORR). Pts with prior allogeneic stem cell transplant were excluded. Pembrolizumab 200 mg was administered intravenously every 3 weeks. NCI CTCAE v4.0 and IWCLL 2008 criteria were used for non-hematological adverse events (AE) and for CLL grade hematological AE. Tumor expression of PD-1 and PD-L1 were assessed with standard immunohistochemical (IHC) staining. Percentage expressions of individual antigens were analyzed with whole-slide scanning followed by image analysis with Image-Pro software (Media Cybernetics). Fluorescence in situ hybridization (FISH) was performed on available CLL/RS tissue sections to assess copy number of chromosome 9p region that contains PD-L1 and PD-L2. Results: 25 pts including 16 CLL and 9 RS (biopsy-proven large cell lymphoma) were enrolled in CLL arm. The median age was 69 years (46-81). Twelve (48%) pts had del(17p) or monosomy 17 or TP53 mutation. The median number of prior therapies was 4 (1-10). 96%, 72% or 48% of pts had received alkylator and anti-CD20 antibody, purine analog or anthracycline. Fifteen (60%) pts had prior ibrutinib and 12 (48%) progressed clinically while receiving ibrutinib, including 6 who progressed to RS and 6 who developed progressive CLL. The median number of pembrolizumab doses that pts received was 3 (1 to 21), administered over a median treatment duration of 11 weeks (1 to 56). Drug-related AE occurred in 21 pts (88%) with the most common ones being neutropenia in 9 (37%), cough in 7 (29%) and dyspnea in 6 (25%) pts. Drug-related grade 3 or above AE occurred in 9 (38%) pts with most common ones being thrombocytopenia (5, 21%), dyspnea (2, 8%), and fatigue (2, 8%). The most common immune-related AE was liver enzyme elevation (12%, 8% G3) and was reversible with therapy interruption or steroid therapy. Based on investigator assessment using the Revised Response Criteria for Lymphomas and IWCLL 2008 criteria, one RS pt had complete response (CR, 4%), 3 RS had partial responses (PR, 12%). Among 9 RS pts, 1 CR (11%), 3 PR (33%), 3 SD (33%) and 2 PD (22%) were observed. Thus the ORR in RS was 44%. No CLL pts achieved a CR/PR, 3 had SD and 9 had progressive disease (PD). The ORR of all pts was 16%. Of the 4 RS who had CR/PR, responses occurred early after 2 cycles of therapy and median duration of therapy for CR/PR pts was 8.3 months with data cut-off by June 30th 2016 (Figure 1A). The causes for therapy discontinuation in RS were PD (3, 33%), alternate therapy (2, 22%), and thrombocytopenia due to increased marrow CLL (1, 11%). Increased marrow CLL was observed in 2 RS pts with PR to RS phase of disease assessed by PET, thus the protocol was amended to allow addition of idelalisib/ibrutinib to control the underlying marrow CLL. For RS pts who had a CR/PR or SD, variable nodal responses were observed (Figure 1B). In particular, 6 RS who had prior ibrutinib experienced CR or PR or SD with nodal responses. After a median follow-up of 10.2 (1.9 to 16.1) months, the median overall survival (OS) for all pts was 10.7 months (95% confidence interval [CI], 5.4 to not reached). The 6 month OS rate for RS and CLL pts were 73% and 59%, respectively. Biomarker assessment using IHC analysis on 10 pts with available tumor/nodal tissues (6 RS and 4 CLL) showed an increased expression of PD-L1 (p = 0.02) and a trend for an increased expression of PD-1 (p = 0.1) in the group of pts with CR/ PR versus pts in the group with no clinical response. One out of 10 tested showed polysomic for chromosome 9p. Conclusion: Pembrolizumab had an acceptable safety profile in CLL and RS patients. We confirmed that pembrolizumab has substantial therapeutic activity in RS. Single-agent pembrolizumab does not appear to have clear activity in CLL. Disclosures Ding: Merck: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding. Shanafelt:GlaxoSmithKline: Research Funding; Genentech: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Hospira: Research Funding.

Abstract Abstract 1792 High risk disease can be identified in patients with early stage chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) using biological prognostic markers. We have shown that early therapy of high risk CLL patients with alemtuzumab (ALM) and rituximab (RTX) is effective and could possibly delay first standard treatment (Cancer 2008;113:2110-8). Efficacy of unconjugated monoclonal antibody (mAb) therapy in these patients could be improved by enhancing mAb mediated cellular cytotoxicity. Preclinical studies show that yeast cell wall derived beta glucan, which increases complement receptor 3 (CR3) binding to the complement fragment iC3b on target cells, could increase mAb mediated cellular cytotoxicity. Both ALM and RTX activate complement resulting in deposition of iC3b on the cell membrane. In CLL cells that are not lysed by complement activation, these iC3b molecules are targets for the effector cells mediating cellular cytotoxicity. We hypothesized that PGG beta glucan (Imprime PPG®, Biothera, Eagan MN) an intravenous formulation of a 1,3/1,6 glucose polymer prepared from a strain of Saccharomyces cerevisiae, would improve the efficacy of therapy with ALM and RTX in patients with CLL by increasing CR3 binding to iC3b and thus enhancing macrophage, neutrophil, and NK cell mediated cytotoxicity. We report the results of a Phase I study of the combination of ALM, RTX and PPG beta glucan in patients with CLL. Methods: The primary aim of this IRB approved study (NCT01269385) was to determine the maximum tolerated dose (MTD) of PGG beta glucan that could be safely combined with ALM and RTX. The MTD was defined as the PGG beta glucan dose level below that which induced dose limiting toxicity in at least one third of patients, or the highest dose level tested if all levels were tolerated. Eligibility for the trial required a diagnosis of CLL by standard (IWCLL-NCI 2008) criteria, no prior treatment for CLL, high risk CLL based on molecular markers, absence of standard indications for initiation of therapy for CLL, and adequate performance status and organ function. High risk CLL was defined as at least one of the following: 17p13-; 11q22-; either unmutated (<2%) IGHV or use of VH3–21 as well as CD38+ and/or ZAP70+. Patients received standard premedication for mAb, antimicrobial and allopurinol prophylaxis and weekly PCR testing for CMV reactivation with treatment of viremia. The duration of treatment was 33 days. PGG beta glucan was administered IV on days 1, 5, 10, 17, 24, and 31 and the first dose was premedicated with hydrocortisone 100mg IV, oral acetaminophen 1000 mg and diphenhydramine 50 mg. The starting dose level of PGG beta glucan was 1 mg/kg, 2nd dose level was 2 mg/kg and the 3rd dose level 4 mg/kg. Subcutaneous ALM therapy started on day 3 with daily dose escalation (3 – 10 – 30 mg) and then 30 mg Mon-Wed-Friday for 4 weeks. Weekly RTX started on day 10 at 375 mg/m2 IV × 4 doses. Results: Thirteen patients were enrolled from February 2011 to April 2012. The 11 evaluable patients had a median age of 61 years (range 47 – 77), 73% were male, 3 had early stage disease (Rai 0) and 8 had intermediate stage disease (Rai I n = 7, Rai II n = 1). High-risk parameters were 17p- in 4 patients, 11q22- in 3 patients, and unmutated IGHV and expression of ZAP70 and/or CD38 in 4 patients. There were no dose limiting toxicities. One patient had grade 4 febrile neutropenia, with no grade 3–4 anemias or thrombocytopenias, and there were no grade 3–4 non-hematological toxicities. All patients responded to therapy with 7 CR, 1 CCR, 1 nPR, and 2 PR (IWCLL-NCI 2008 criteria). Median follow up was 6.9 months (2.3 – 13.2) and one patient progressed at 9.7 months. No patients have required treatment for progressive disease and there have been no patient deaths. Two patients were not evaluable: One developed neutropenia and therapy was not held per protocol, and the other developed a grade 2 skin reaction to ALM and treatment was stopped. Discussion: The combination of PGG beta glucan with ALM and RTX is well tolerated at a PGG beta glucan dose of 4 mg/kg. All patients responded to therapy with 64% achieving a CR. These data support continuation of this study in a phase II component. Acknowledgment: This study was funded by the University of Iowa/Mayo Clinic Lymphoma SPORE (CA097274) and Biothera. Disclosures: Zent: Biothera: Research Funding; Genzyme: Research Funding; Genentech: Research Funding; Novartis: Research Funding; GlaxoSmithKline: Research Funding. Off Label Use: Phase I study using PGG beta glucan in CLL.

Abstract INTRODUCTION: Among patients (pts) with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), the indications for liver biopsy are not known. Additionally, the histopathologic findings of CLL infiltration in the liver along with its clinical implications have not been thoroughly described in the literature. METHODS: We identified all pts with a diagnosis of CLL/SLL from the CLL Clinical Database at Mayo Clinic, Rochester, MN who underwent a liver biopsy. We also cross referenced the Mayo Clinic Hematopathology Database for all pts who underwent a liver biopsy. The indications for biopsy, description of the pathologic findings in the liver biopsy, CLL therapy and outcomes were abstracted from the clinical records. Retrospective pathology review was performed on cases with CLL involvement in which slides were available for review. RESULTS: Fifty-two CLL/SLL pts who underwent a liver biopsy were identified. The indications for liver biopsy were as follows: liver lesion identified on radiographic imaging in 21 (41%) pts, abnormal liver function tests (LFTs) in 17 (33%) pts, hepatosplenomegaly in 11 (21%) pts, and unknown in 3 (6%) pts. Among all 52 pts, there was concern for Richter transformation at time of biopsy in 7 (13%) pts. Types of biopsy were as follows: percutaneous in 20 (39%) pts, intraoperative in 17 (33%) pts, transjugular in 3 (6%) pts, and unknown in 12 (23%) pts. CLL/SLL involvement was identified in 38/52 (73%) pts undergoing liver biopsy. Among these, the diagnosis of CLL/SLL was made on liver biopsy in 8 pts, and 7 pts had additional findings on their liver biopsy including metastatic colon cancer (n=3), hemochromatosis (n=2), steatohepatitis (n=1), and cirrhosis (n=1). Liver biopsy revealed Richter transformation in 4 (8%) pts (3 pts with diffuse large B cell lymphoma (DLBCL) and 1 patient with Hodgkin lymphoma), other malignancy in the absence of CLL in 7 (15%) pts (2 metastatic colorectal, 2 metastatic esophageal, 1 hepatocellular carcinoma, 1 metastatic lung, and 1 neuroendocrine), and 1 patient with steatohepatitis. Two (4%) pts had normal findings on liver biopsy. Among the 38 pts with liver involvement by CLL, 27 had slides available for retrospective pathology review. CLL involvement ranged from 2-100% of the liver parenchyma. Seven pts (26%) underwent excisional biopsies or resections and 20 (74%) underwent core biopsies. The portal tracts were the most common region of the liver involved (22/26 pts, 85%). Of these, 8/22 (36%) pts had extension into the lobules or sinusoids, as well. Of the 4 cases without portal involvement, 2 showed extensive involvement such that it effaced the liver parenchyma in the region of involvement. One patient (4%) had a predominantly sinusoidal involvement. One patient (4%) showed small nodular infiltrates that were difficult to localize due to their size. Proliferation centers were noted in only 3 pts (11%). Most pts (29/38; 76%) whose liver biopsy demonstrated involvement by CLL did not receive immediate CLL-specific treatment. Nine of the 38 pts (24%) with CLL involvement on liver biopsy received therapy (Table): purine analog based therapy (n=4), rituximab and steroids (n=2), steroids only (n=1), alkylator and rituximab (n=1), and ibrutinib (n=1). Pts with extensive involvement of the liver by CLL were more likely to receive purine nucleoside analog based therapy compared to pts with portal infiltration by CLL (2/2 pts [100%] vs. 1/6 pts [17%]). The remaining pts were offered no therapy due to incidental finding of CLL in the liver biopsy (n=11), chemotherapy for other cancer (n=5), palliative care (n=3), or unknown (n=10). Pts with Richter's transformation received R-CHOP (n=2) and CHOP (n=1) for DLBCL, and ABVD (n=1) for Hodgkin lymphoma. Pts with other cancers without CLL received appropriate therapy for their underlying malignancy. CONCLUSION: Abnormal LFTs and radiographic abnormalities were the most common indications for a biopsy in this large cohort of CLL pts. Infiltration of the portal tracts by CLL/SLL was the most common histopathological finding. Proliferation centers were not commonly seen, which may make the diagnosis challenging for the pathologist if there is not a prior history of CLL/SLL. The mere presence of CLL/SLL infiltration did not mandate treatment and many pts were able to continue observation. Table Table. Disclosures Ding: Merck: Research Funding. Kenderian:Novartis: Patents & Royalties, Research Funding. Shanafelt:GlaxoSmithkKine: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Genentech: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding.