Leis, José F.

Abstract Background: High risk CLL patients treated with novel targeted therapies continue to experience disease progression (PD), and more than 50% of these PD patients evolve into Richter's syndrome (RS), (Maddocks, Jama Oncol 2015). Standard chemotherapy for large cell lymphoma has limited efficacy (median overall survival <12 months) in RS. Novel immunotherapy using a PD-1 antibody to block immune checkpoint signals to activate the cytotoxic T -cell has significant efficacy in relapsed Hodgkin lymphoma (Ansell, NEJM 2015). We conducted a phase 2 trial to test the safety and clinical efficacy of the anti-PD-1 antibody pembrolizumab in patients with relapsed/refractory CLL and relapsed low grade B non-Hodgkin lymphoma (B-NHL) (MC1485 trial). Methods: MC1485includes two arms: patients with relapsed/refractory CLL (including RS) and patients with relapsed B-NHL. The main end points of this study are safety and overall response rate. The first 6 patients enrolled in either arm were included in a designed safety interim analysis. Here we report the initial interim analysis from the CLL arm. Relapsed/refractory CLL including RS who had ECOG performance 0-2 and normal organ function were included. Patients with active autoimmune disease or interstitial lung disease were excluded. Pembrolizumab 200 mg was administered intravenously every 3 weeks until progression, excessive toxicity, or completion of 2 years of therapy. Soluble plasma PD-L1 levels were measured in these 6 patients using an established ELISA assay (Frigola, Clin Cancer Res, 2011). CD8+ T cell subsets were assessed for their functional status using an established analysis (Liu, Oncoimmunology. 2013) at baseline and after 2 cycles of therapies. Results: As of July 27th, 2015, 16 relapsed/refractory CLL patients including 5 RS patients were enrolled. The median age was 71 years (58-81). The median number of prior therapies was 3 (1-6). All CLL patients had received chemoimmunotherapy (FCR/PCR). 4 out of 5 RS patients had received anthracycline-containing chemotherapy. 5 out of 8 patients who had received prior ibrutinib therapy progressed on ibrutinib. 8 patients had 17p-/TP53 mutation. Herein, we report preliminary results from the interim analysis of CLL arm including 4 RS and 2 CLL as well as the 5th RS who had response evaluation by PET. The median cycles of therapy administered was 4 (3-7). One patient experienced grade 2 cytokine release syndrome with transient febrile neutropenia, grade 3 headache and skin rashes. These symptoms resolved with steroid therapy. One patient experienced grade 3 myalgia and was also treated with steroids. The other patients in this safety cohort tolerated pembrolizumab well. The most common drug-related adverse events were grade 1 dyspnea (33%, 2/6) and grade 1 anemia (33%, 2/6). Based on investigator assessment using the Cheson 2007 International Working Group Criteria, 4 out of 5 RS patients had responded to therapy. One patient had a complete remission after 2 cycles and remains in remission. One patient had almost complete PET response after two cycles and is classified as PR as her bone marrow have not been re-evaluated yet. Two patients had notable responses with nodal and skin lymphoma improvements before they showed potential evidence of progressive diseases. The remaining 1 RS and 2 CLL had stable disease and continued on therapy at the last follow-up. Soluble PD-L1 levels (sPD-L1, n=6) were measured at baseline and after 2 cycles of therapies. 3 RS patients who had responded to therapy had decreased or stable sPD-L1 levels. The 4th RS and two CLL had increased sPD-L1 levels and had not demonstrated clinical response. CD8 T-cell subset analyses performed blindly (n=4) showed increased CD8 T cell function in one of the 4 patients tested. This patient who demonstrated CD8 T cell functional enhancement is the only patient in the 4 tested patients who had notable response to pembrolizumab. Conclusion: Pembrolizumab is tolerated in relapsed CLL and RS patients. Early efficacy observed in heavily pretreated RS patients including patients progressed on both anthracycline-based treatment and ibrutinib indicate PD-1 inhibition is a promising novel approach in patients with RS. Our CD8 T cell subset analysis may be used as a biomarker assay to predict clinical response in the era of novel immunotherapy. This trial and further correlative analysis is ongoing and will be presented at the ASH meeting. Disclosures Ding: Merek: Research Funding. Shanafelt:Cephalon: Research Funding; Pharmactckucs: Research Funding; Janssen: Research Funding; Hospira: Research Funding; Polyphenon E Int'l: Research Funding; Celgene: Research Funding; Glaxo-Smith_Kline: Research Funding; Genentech: Research Funding. Kay:Tolero Pharma: Research Funding; Hospira: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Celgene Corporation: 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. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding.

Abstract Abstract 1749 BACKGROUND: We have previously reported that transformation of a myeloproliferative neoplasm (MPN) to acute leukemia or blast phase (MPN-BP) is accompanied by a median survival of 2.6 months (range 0–24.2 months) (Mesa et. al. Blood 2005) despite treatment. Allogeneic stem cell transplantation (ASCT) offers a potential for cure. We reviewed 13 patients with MPN – BP who were candidates for ASCT, and 8 of those patients received ASCT after induction chemotherapy. METHODS: Retrospective analysis of individuals who had a clear antecedent myeloproliferative neoplasm (essential thrombocythemia (ET), polycythemia vera (PV), or myelofibrosis (MF) (either primary (PMF) or post ET/PV)), transformed to MPN-BP, and were candidates for ASCT. Clinical characteristics at each phase of illness, therapy at each phase of illness, and outcome of ASCT were assessed. RESULTS: Patients (MPN details): Thirteen patients (8 male, 5 female, median age at diagnosis of MPN 42 years in those who underwent ASCT and 64 years in those who did not receive ASCT (combined median 53 years, range 26–70)) were identified who met the inclusion criteria, of whom 2 had ET, 4 PV, 2 Post-ET MF, 1 Post-PV MF and 4 PMF. Jak2-V617F mutation was present in 7 of 8 patients tested. Treatments used during the MPN phase included hydroxyurea in 9 (+ busulfan in 1 and + anagrelide in 1), and thalidomide/prednisone in 2 (two patients received no treatment prior to MPN-BP). Patients (MPN-BP details): Transformation of an MPN to blast phase (from diagnosis of MPN) occurred after a median of 11 years in those who underwent ASCT and 8 years in non-ASCT (range 3 months to 30 years). At the time of MPN-BP diagnosis, 9 patients had an abnormal karyotype, 3 with complex karyotypes, 3 with trisomy 8 (sole abnormality), 1 with del(7q), 1 with del(13q). Leukemic induction consisted of standard anthracycline/cytarabine combination therapy (+/− etoposide), except for one patient received a study medication voreloxin. One patient who did not receive ASCT had remission after induction, but later expired from relapse, two expired soon after leukemic transformation, and two were too ill to receive induction. In the ASCT group (N=8), 5 patients achieved complete remission (CR) of their leukemia/return to MPN chronic phase (one of the five patients required a second induction to achieve CR), while 3 patients were considered primary induction failures due to persistence of > 5% blasts in the blood (2) or marrow (1) at the time of pre-transplant response assessment. The median time from diagnosis of MPN-BP to ASCT was 128 days. ASCT Details and Outcomes: Patients (median age of 55 years at time of ASCT; range 44–73) underwent ASCT (all HLA identical, 3 matched unrelated donors, 5 matched sibling donors) with either reduced intensity conditioning (n=6) or fully myeloablative conditioning (n=2). After a median follow-up of 488 days (range 127 – 1206), 6 of 8 patients are alive and free of disease. MPN-BP recurred in two patients at day 69 and 77 post-transplant; both patients eventually died of progressive leukemia, one after a second transplant. Acute GVHD occurred in 3 patients (1 grade III, 2 grade II), and chronic GVHD in 4 (2 mild, 2 moderate). All five patients who achieved CR (marrow and PB blasts < 5%) after induction therapy remain in continuous CR, while 2 of the 3 patients with evidence of persistent leukemia relapsed and died of MPN-BP. No patient died of transplant-related causes and all patients engrafted promptly. CONCLUSION: Rapid induction followed by ASCT can offer a curative path for individuals with MPN-BP. Although limited by small numbers, our data suggest that leukemic clearance (marrow blast percentage < 5%) prior to ASCT is associated with improved outcome. Disclosures: Mesa: Incyte: Research Funding; Lilly: Research Funding; SBio: Research Funding; Astra Zeneca: Research Funding; NS Pharma: Research Funding; Celgene: Research Funding.

Abstract Abstract 1977 Introduction: Transplant options are limited for adult patients (pts) who lack a fully matched related or unrelated donor. We hypothesized that in-vivo T-cell depletion with r-ATG would allow safe allo-SCT from mismatched, unrelated donors, thus expanding the potential donor pool for pts with hematologic malignancies who require allo-SCT. Patients and Methods: Thirty seven adult pts (age 20 – 70, median 45) underwent a first unrelated, mismatched, allo-SCT between 1/1/2006 and 6/30/2011 at Mayo Clinic Arizona for hematologic malignancy (35 PBSC, 2 marrow). All pts had at least a one allele or one antigen mismatch (MM) at HLA-A, -B, -C, or -DRB1, and all except one pt received r-ATG as part of the GVHD prophylaxis strategy (dose range 2.5 – 10 mg/kg in daily dose of 2.5 mg/kg depending on degree of mismatch, with the last dose generally given on day −1). One pt received Campath after experiencing anaphylaxis to r-ATG. Pts were transplanted for acute myeloid leukemia (n = 19; 10 CR1, 6 CR2, 3 other), acute lymphoblastic leukemia (n = 8; 4 CR1, 4 CR>/= 2), chronic myeloid leukemia (n = 1), myelodysplastic syndrome (n = 5), or non-Hodgkin lymphoma (n = 4). Conditioning was myeloablative in 20, reduced intensity in 16, and non-myeloablative in 1. Mismatches were as follows: 1-allele MM (n = 7); 1 antigen MM (n = 15); 2 allele MM (n = 4); 1 antigen, 1 allele MM (n = 7); and 2 antigen MM (n = 4). Additional GVHD prophylaxis included tacrolimus plus either methotrexate (n =21), mycophenolate mofetil (n = 14), or other (n = 2). Results: The median follow-up for surviving pts is 12 months. As of 6/30/11, 31 pts were alive, and 6 had died of the following causes: multiorgan failure (n = 1), relapse (n = 3), and veno-occlusive disease (n = 2). To date, there have been no deaths related to acute or chronic GVHD. The 1- and 2-year estimated rates of overall survival are 84.5%/78.8% (Fig. 1); of progression-free survival 79.7%/72.0%. The estimated rate of relapse at 1 and 2 years is 11.8%/18.7%, and of non-relapse mortality 8.1%/10.5%. Four pts (10.8%) have developed severe (grades III-IV) acute GVHD by day 100 (days 19, 27, 30, 43; one pt after withdrawal of prograf due to transplant-associated microangiopathy). No late onset severe acute GVHD has been seen. Moderate to severe NIH-defined chronic GVHD occurred in a single pt at risk (cumulative incidence estimate 2.4% at 1 year, 4.7% at 2 years; Fig. 2). Four pts have reactivated EBV, with one developing PTLD (all have been treated with Rituximab). CMV reactivation was seen in 24 pts (65%), CMV disease in 4, with no deaths directly related to CMV. Conclusions: In vivo T-cell depletion with r-ATG abrogates severe acute and chronic GVHD, and allows use of mismatched unrelated donors for allo-SCT in adult pts with otherwise incurable hematologic malignancies. Long-term survivors are generally free of severe chronic GVHD, with good quality of life. There does not appear to be an increased incidence of disease relapse, and non-relapse mortality is low. This approach is safe, effective, and considerably expands the donor pool for adult pts who require allo-SCT. Disclosures: Reeder: Celgene: Research Funding; Millennium Pharmaceuticals Inc.: Research Funding; Novartis: Research Funding. Mesa:Incyte: Research Funding; Lilly: Research Funding; SBio: Research Funding; Astra Zeneca: Research Funding; NS Pharma: Research Funding; Celgene: Research Funding.

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&lt;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&lt;0.001; age ≥75 HR=3.6, p&lt;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&lt;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 Abstract 4610 Introduction: Infections are a major cause of morbidity and mortality in patients with chronic lymphocytic leukemia (CLL). Up to 50% of patients with CLL will develop infectious complications during the course of their disease, and 30–50% of all deaths from CLL are attributed to infections and infectious complications. The risk of infection in CLL is related to immune deficiencies associated with the primary disease process, as well as immunosuppression secondary to treatment. Available research on infectious complications of CLL has focused on patients in clinical trials receiving chemotherapy. Little is known about the natural history of infection in community dwelling patients with newly diagnosed CLL. Method: To explore the natural history of infection in a local, community dwelling cohort of patients diagnosed with CLL, we used the Mayo Clinic CLL database to identify all patients with newly diagnosed CLL seen in the Mayo Clinic Division of Hematology after January 1, 1999 and who resided within 50 mi of Mayo Clinic (Rochester, MN). All patient hospitalizations were reviewed to document infection including cross-referencing with the electronic Mayo Clinic infection database which includes all culture and serology results obtained from hospitalized Mayo Clinic patients. Patients who had positive blood, sputum, cerebrospinal fluid, pleural fluid, or paracentesis fluid culture results were identified. Patients whose cultures were negative were considered to have culture negative infection. Serologies and viral assays (e.g. CMV viral load) were also reviewed to identify infections. Results: In May 2010, there were 2022 patients in the Mayo Clinic CLL Database with the diagnosis of CLL/SLL made between Jan 1999 – Dec 2009. Of these, 336 (17%) patients resided within a 50 mi radius of Mayo Clinic and were considered non-referred, community-based CLL patients. Median age at diagnosis for these 336 patients was 69 yrs (range 27–97) and most had early stage CLL (57% stage 0; 34% stage I-II). With respect to prognostic markers, 206 (70%) patients were CD38 negative, 125 (64%) ZAP-70 negative, 85 (53%) IgVH mutated, and 101 (63%) had either no abnormality or 13q14- as a sole abnormality on FISH analysis. Consistent with being a community dwelling cohort, ~90% (152/165) of patients had co-morbid health problems and ~50% (86/165) had a major comorbidity (e.g. coronary artery disease, cerebral vascular disease, CHF, diabetes, COPD, other malignancy). Although ~17% (43/249) of patients had gamma-globulin levels below the reference range at diagnosis, only 2% (6/249) had an IgG level <500 mg/dL. Median follow-up for all patients was 49 months (range 0–121) and 104 (31%) patients progressed to require treatment for CLL. Although 222 (66%) patients required hospitalization during follow-up, only 38 (11.3%) were hospitalized with infection. Collectively, these 38 patients were hospitalized for infection 139 times (median 2 hospitalizations for infection per patient). Among these 38 patients, 13 had no organism identified on cultures (culture negative infection) while the remaining 25 (66%) had an organism identified during at least hospitalization for infection. Of the 38 patients hospitalized with infection, 18/38 (47%) had a gram positive organism (8 strep pneumonia, 11 staphylococcus Aureus, 2 nocardia), 11/38 (29%) had a gram negative organism (3 E.Coli, 4 Pseudomonas, 4 Hemophilus influenzae), 5/38 (13%) a mycobacterial infection (4 MAC, 1 M. gordonae), 15/38 (40%) a cytomegalovirus infection, 19/38 (50%), cryptococcus and/or cryptosporidium (18 cryptococcus AG, 4 cryptosporidium), and 12/38 (32%) a filamentous fungi infections (12 aspergillous). In aggregate, hospitalization for an opportunistic infection (e.g. cytomegalovirus, cryptococcus, filamentous fungi, myocobacteria, pneumocystis) occurred in 26/336 (8%) CLL patients during follow-up. Being male (OR 2.7; p=0.02), ZAP-70+ (OR 3.9; p=0.004), IGHV unmutated (OR 5.5; p=0.002), and receiving treatment (OR 4.7, p<0.001; Figure) were associated with increased risk of hospitalization for infection. Conclusions: Approximately 8% of newly diagnosed, community dwelling CLL patients will require hospitalization for opportunistic infection at some point during the course of their disease. Gender, disease factors (e.g. ZAP-70, IGHV status), and treatment characteristics are associated with infection risk. Disclosures: Zent: Genzyme: Research Funding; Genentech: Research Funding; Novartis: Research Funding; G.S.K.: Research Funding. Shanafelt:Celgene: Research Funding; Hospira: Research Funding; Genentech: Research Funding.

Abstract Abstract 1241 Poster Board I-263 Background and Significance Monoclonal B lymphocytosis (MBL) is a hematologic syndrome characterized by accumulations of clonal B lymphocytes in the peripheral blood. Most MBL have a CLL-like immunophenotype, though other, less common phenotypes are observed. Although some MBL, particularly those with MBL cell counts >1.9 × 109 / L, progress to CLL, “low count” MBL (<0.2 × 109 MBL / μL) have little potential to progress to MBL and may have different biologic characteristics from MBL with lymphocytosis or Rai Stage 0 CLL. Our hypothesis was that detailed characterization of family-associated MBL may also provide biologic insights into the pathogenesis of CLL. Methods Individuals with MBL were identified by flow cytometry screening of fresh and cyropreserved peripheral blood from unaffected members of CLL kindreds ascertained by Genetic Epidemiology of CLL Consortium (GEC) sites. We defined MBL as populations of CD5+, CD19+, CD20lo, CD23+ B cells that comprised at least 0.02% of the PBMC and did not exceed 5.0 × 109 MBL cells / L. Flow cytometry was used to determine the surface immunophenotype including prognostic parameters of CD38, intracellular ZAP-70, immunoglobulin isotype, CD49d, and the ratio of CD69:71. mRNA and genomic DNA from single MBL cells isolated by flow cytometric sorting were analyzed using PCR to determine immunoglobulin heavy and light chain sequences (IGVH status). MBL cells were sorted in bulk for FISH determination of genetic loci associated with clinical CLL. Results Fifty-four unaffected family members were found to have MBL, of these 48 (89%) showed a typical CLL immunophenotype (CLL-like MBL). We observed significant variability in the size of the MBL clone as a percentage of the CD19+ B cell compartment (mean 30%, median 16%; range 2% - 97%). CD38 positive (defined as CD38 surface expression in ≥ 30% of MBL cells) was observed in 6 of 38 (16%) subjects tested. ZAP-70 positive (defined as intracellular expression in ≥ 20% of MBL cells) was expressed in 5 of 28 (18%) participants. CD49d positive (defined as surface expression in ≥ 45% of MBL cells) was observed in 4 of 17 (24%) subjects. The ratio of surface expression of CD69:CD71, a measure of cellular activation that also correlates with an unmutated IGVH, was ≥2.0 in 3 of 34 (9%) subjects tested. Among 36 subjects tested, 9 (25%) MBL expressed both surface IgD and IgM (defined as surface expression ≥ 40% for both IgM and IgD), 12 (33%) expressed IgD only, 2 (6%) expressed IgM only, and 13 did not express IgD or IgM (36%). Analysis of IGVH status has been completed in 10 individuals. Both immunoglobulin heavy chain variable (IGVH) region mutated (n = 14) and unmutated (n = 5) sequences were observed. Six of 10 individuals had 2 or more unrelated MBL clones (range 2 - 4), including two individuals with both unmutated and mutated clones. Among the 19 MBL clones identified in these 8 subjects, VH3 or VH4 rearrangements were observed in all MBL clones. The most commonly rearranged IGVH genes were 3-07 (3 MBL clones), 3-15 (3), and 4-34 (3). No VH1 family gene rearrangements were observed. MBL cells were bulk sorted for FISH from 14 subjects. Mono or biallelic deletion of 13q14.3 was observed in 9 subjects, 4 were normal, and one showed trisomy 12. Conclusions Our data affirms that CLL-like MBL are commonly observed among the unaffected family members from CLL kindreds. We found that family associated MBL clones (most of which were small clones) express ZAP-70, CD38, and CD49d at an apparently lower frequency than observed in CLL. Unlike in CLL, the surface immunoglobulin isotype showed co-expression of IgM and IgD in only one third of cases. Moreover, small MBL clones are commonly oligoclonal and predominantly express mutated IGVH genes with an IGVH usage that also appears different from CLL. Taken together, these findings suggest that small MBL clones, though phenotypically similar to CLL, have important biologic differences from CLL that may explain the limited potential of these clones to progress to CLL. The clinical outcome of these MBL clones in relation to our baseline prognostic characterization will be of interest. In addition the further investigation of family associated MBL is being conducted and may clarify the genetics and immunobiology of familial CLL. Disclosures No relevant conflicts of interest to declare.

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 Abstract 1246 Poster Board I-268 B-cell chronic lymphocytic leukemia (B-CLL) is characterized by a variable clinical course. Genomic aberrations as detected by FISH analysis and the mutational status of the IgVH genes have been found to have prognostic clinical significance with unmutated IgVH genes associated with clinically more aggressive disease. Previous studies have suggested that unmutated IgVH B-CLL is associated with increased chromosomal instability and increased chromosomal aberrations leading to accelerated disease progression. We recently performed a high-throughput, high-resolution array-based comparative genomic hybridization (aCGH) in a cohort of B-CLL patients. Fifty-eight patients have been analyzed by using the Sureprint G3 microarray (one million probes, Agilent). Our working hypothesis was that we would see increased genomic aberrations and instability in the unmutated IgVH group. The total number of copy number aberrations and total megabases (Mb) deleted or gained per genome were used as a surrogate marker for genomic instability. Variations in chromosomal aberrations in various VH families were also evaluated. B-CLL with unmutated IgVH genes utilized members of the VH1, VH3, VH4 and VH5 families with VH1-69 the most prevalent. B-CLL with mutated IgVH genes utilized VH families VH1, VH2, VH3, VH4, and VH6. Considerable variation was seen in the number of genomic abnormalities between cases. Overall, 315 abnormalities have been identified (236 deletions and 79 gains), with a median of 4 copy-number abnormalities per patient (range 0-32). In patients with IgVH mutational status available the median number of chromosomal aberrations in the mutated group was 5 (range 1-17) and unmutated group was 4 (range 0-20). Copy number deletions were significantly more common than chromosomal gains for the total group and in both the unmutated and mutated IgVH gene groups. Mean number of megabases (Mb) of DNA deleted in the unmutated IgVH group was 17.80Mb (standard deviation 24.17 Mb, median 6.63 Mb, range 0 - 90.55Mb) and 40.65 Mb in the mutated IgVH group (standard deviation 86.04 Mb, median 15.35Mb, range 0 – 307.57Mb). Mean number of Mb gained in the unmutated group was 37.74Mb (standard deviation 57.58Mb, median 0.44Mb, range 0 – 132.47Mb) and 32.99Mb (standard deviation 59.76Mb, median 0.14Mb, range 0 – 172.50Mb) in the mutated group. Nine patients had B-CLL with VH1-69 genes and 8 of them were unmutated. Median number of chromosomal deletions was 2 and gains also 2 (ranges 0 – 8 deletions and 0 – 4 gains) for this group. Similar findings were seen for the other VH families. These results initially suggest that total copy number variations do not account for the observed clinical differences between mutated and unmutated IgVH B-CLL. The catalogue of potentially clinically relevant chromosomal abnormalities found in this aCGH study is being currently evaluated. Disclosures Zent: Genentech, Bayer, Genzyme, Novartis: Research Funding. Shanafelt:Genentech: Research Funding; Hospira: Membership on an entity's Board of Directors or advisory committees, Research Funding; Polyphenon E International: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Bayer Health Care Pharmaceuticals: Research Funding. Kay:Genentech, Celgene, Hospira, Polyphenon Pharma, Sanofi-Aventis: Research Funding; Biogenc-Idec, Celgene, Genentech, genmab: Membership on an entity's Board of Directors or advisory committees. Fonseca:BMS: Consultancy; Amgen: Consultancy; Otsuka: Consultancy; Celgene: Consultancy; Medtronic: Consultancy; Genzyme: Consultancy.

Abstract Abstract 1232 Poster Board I-254 B-Chronic Lymphocytic Leukemia (CLL) shows a strong familial risk and also co-aggregates with other indolent lymphomas. Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic hematologic condition characterized by small B-cell clones, most with a surface phenotype similar to that of chronic lymphocytic leukemia (CLL). These clones are detectable at low absolute lymphocyte cell (ALC) numbers in otherwise healthy individuals using sensitive 6 or 8 color flow cytometry analysis and can be a precursor to CLL. In the general population, MBL increases with age with a prevalence of 5% in individuals over age 65. In contrast, the rate of MBL is 13-18% in first degree relatives of CLL patients in high risk families. In the largest study to date, we report the characteristics of MBL among 430 first-degree relatives of CLL patients (with no associated lymphoproliferative diseases [LPD]) in 132 high risk families. Patients and Methods Individuals studied came from “high risk” families (defined as those with two or more confirmed cases of CLL) that are participating in the Genetic Epidemiology of CLL Consortium. Multi-parameter flow cytometry analysis with a detection sensitivity of 0.02% was performed on either fresh or cryopreserved PBMC and MBL was classified according to previously published criteria (Marti et al, Br. J Haematol 130:325, 2005). Both the ALC and the absolute B cell count (B-ALC) were calculated for each individual. Survival analysis was used to compute the probability of developing MBL with age using the life table method. Results The overall rate of MBL was 17% (73/430) among first–degree relatives but the probability for developing MBL by age 90 was 51%. Males had a slightly higher (but non-significant) risk for MBL than females. MBL patients had significantly higher ALC and B-ALC than did those with normal immunophenotype. The mean ALC was 2.5×109/L among MBL patients, and 20% had an ALC greater than 3 ×109/L. The B-ALC count averaged 0.51 ×109/L. Ninety percent of the MBL cases had a CLL-like phenotype (CD20dim, CD5+, CD23+). Conclusions MBL is found at a very high rate in families selected for having 2 or more patients with CLL suggesting that MBL reflects inherited predisposition to CLL. Although most of the MBL cases in these families had low cell counts and thus have a presumed low likelihood of progressing to CLL or other LPD, a higher proportion of them had lymphocytosis compared to those with normal immunophenotype. We hypothesize that if MBL is an early step in the process of development of CLL, then germ line genes are likely to be acting early in carcinogenesis with more “hits” required before CLL develops. By looking for genes associated with MBL or CLL in families or in the population, we could substantially increase our power to identify germ line genes predisposing to CLL. Disclosures Kay: Biogenc-Idec, Celgene, Genentech, genmab: Membership on an entity's Board of Directors or advisory committees; Genentech, Celgene, Hospira, Polyphenon Pharma, Sanofi-Aventis: Research Funding.