ALBERT

Description: Lakes are a nitrous oxide (N 2 O) source to the atmosphere, but the biogeochemical controls and microbial pathways of N 2 O production are not well understood. To trace microbial N 2 O production (denitrification, nitrifier denitrification, and nitrification) and consumption (denitrification) in two basins of Lake Lugano, we measured the concentrations and N and O isotope compositions of N 2 O, as well as the intramolecular 15 N distribution, i.e., site preference (SP). Our results revealed differential N 2 O dynamics in the two lake basins, with N 2 O concentrations between 12 nmol L −1 and 〉 900 nmol L −1 in the holomictic South Basin, and significantly lower concentrations in the meromictic North Basin (〈13 nmol L −1 ). In the South Basin, the isotope signatures reflected a complex combination of N 2 O production by nitrifying bacteria through hydroxylamine (NH 2 OH) oxidation, N 2 O production through incomplete denitrification, and N 2 O reduction to N 2 , all occurring in close vicinity within the redox transition zone (RTZ). In the North Basin, in contrast, the N 2 O isotopomer signatures suggested that nitrifier denitrification was the main N 2 O source. The pronounced decrease in N 2 O concentrations to undetectable levels within the RTZ, in tandem with an increase in δ 15 N-N 2 O, δ 18 O-N 2 O, and SP indicated quantitative N 2 O consumption by microbial denitrification. In the northern basin this was primarily sulfide-dependent. The apparent N and O isotope enrichment factors associated with net N 2 O consumption were 15 ε ≈ 3.2‰ and 18 ε ≈ 8.6‰, respectively. The according 18 O to 15 N enrichment ratio ( 18 ε : 15 ε ≈ 2.5) is consistent with previous reports for microbial N 2 O reduction, underscoring its robust nature across environments.

Description: Chronic lymphocytic leukemia (CLL) is characterized by the existence of subsets of patients with (quasi)identical, stereotyped B cell receptor immunoglobulins (BcR IG). Patients in certain major stereotyped subsets often display remarkably consistent clinicobiological profiles, suggesting that the study of BcR IG stereotypy in CLL has important implications for understanding disease pathophysiology and refining clinical decision-making. Nevertheless, several issues remain open, especially pertaining to the actual frequency of BcR IG stereotypy and major subsets, as well as the existence of higher-order connections between individual subsets. In order to address these issues, we investigated clonotypic IGHV-IGHD-IGHJ gene rearrangements in a series of 29,856 patients with CLL, by far the largest series worldwide. We report that the stereotyped fraction of CLL peaks at 41% of the entire cohort and that all 19 previously identified major subsets retained their relative size and ranking, while 10 new ones emerged; overall, major stereotyped subsets had a cumulative frequency of 13.5%. Higher-level relationships were evident between subsets, particularly for major stereotyped subsets with unmutated IGHV genes (U-CLL), for which close relations with other subsets, termed 'satellites', were identified. Satellite subsets accounted for 3% of the entire cohort. These results confirm our previous notion that major subsets can be robustly identified and are consistent in relative size, hence representing distinct disease variants amenable to compartmentalized research with the potential of overcoming the pronounced heterogeneity of CLL. Furthermore, the existence of satellite subsets reveals a novel aspect of repertoire restriction with implications for refined molecular classification of CLL.

Description: The IGHV4-34 gene is very frequent (~10%) in the B cell receptor immunoglobulin (BcR IG) gene repertoire of chronic lymphocytic leukemia (CLL). Over 30% of IGHV4-34 CLL cases can be assigned to different subsets with stereotyped BcR IG. The largest is subset #4 which represents ~1% of all CLL and ~10% of IGHV4-34 CLL and is considered a prototype for indolent disease. The BcR IG of a great majority (~85%) of IGHV4-34 CLL cases carry a significant load of somatic hypermutation (SHM), often with distinctive SHM patterns. This holds especially true for stereotyped subsets and is suggestive of particular modes of interactions with the selecting antigen(s). In detail, subsets #4 and #16, both involving IgG-switched cases (IgG-CLL), exhibit the greatest sequence similarity in SHM profiles, whereas they differ in this respect from IgM/D subsets #29 and #201. Prompted by these observations, here we explored the extent that these subset-biased SHM profiles in different IGHV4-34 stereotyped subsets were reflected in distinct demographics, clinical presentation, genomic aberrations and outcomes. Within a multi-institutional series of 20,331 CLL patients, 1790 (8.8%) expressed IGHV4-34 BcR IG. Following established bioinformatics approaches for the identification of BcR IG stereotypy, 573/1790 IGHV4-34 CLL cases (32%) were assigned to stereotyped subsets; of these, 340 cases (19% of all IGHV4-34 CLL and 60% of stereotyped IGHV4-34 cases) belonged to subsets #4, #16, #29 and #201, all concerning IGHV-mutated CLL (M-CLL). Clinicobiological information was available for 275/340 patients: #4, n=150; #16, n=44; #29, n=39; and #201, n=42. Comparisons between subsets revealed no differences in gender and age distribution. Interestingly, however, 36-43% of each subset cases were young for CLL (defined as patients aged ≤55 years), which is higher compared to general CLL cohorts, where young patients generally account for ~25% of cases. In contrast, significant differences were identified between subsets regarding: (i) disease stage at diagnosis, with 〉90% of IgG subsets #4 and #16 diagnosed at Binet stage A versus 83% in subset #201 and 74% in subset #29 (p=0.029); (ii) CD38 expression, ranging from 1% in subset #4 to 10% in subset #201 (p=0.013); (iii) the distribution of del(13q), peaking at a remarkable 92% in subset #29 versus only 37% in subset #16 (p

Description: Introduction Ibrutinib is an oral irreversible inhibitor of Bruton's tyrosine kinase for treatment of chronic lymphocytic leukemia (CLL). Ibrutinib has demonstrated superior efficacy for patients with TP53 aberration or relapsed/refractory (R/R) CLL; and more recently superior progression free survival (PFS) has been demonstrated compared to chemoimmunotherapy as first line therapy. However, knowledge about the outcomes and adverse events (AE) upon ibrutinib among patients at a population-based level are still limited. The aim of the here presented study is to explore outcomes of ibrutinib treatment in a population-based cohort of patients with CLL treated with ibrutinib in Denmark. Methods In this retrospective study, patients from 8 hospitals in Denmark, who were diagnosed with CLL and treated with ibrutinib from April 2014 until February 2019 were included. Medical records were retrospectively reviewed to obtain information. Patients receiving ibrutinib within clinical trials were excluded. Overall survival (OS) was defined as time from ibrutinib start to death from any cause while PFS was defined as time from ibrutinib start to progression or death from any cause. PFS and OS were analyzed with the Kaplan-Meier method while cumulative incidence was calculated with the Aalen-Johansen estimator. Results In total, 205 patients with CLL receiving ibrutinib treatment were identified from hospital records and registries. The median follow-up was 21.4 months (IQR, 11.9-32.8) and the median time on ibrutinib was 16.8 months (IQR, 6.0-28.1). The median age at treatment initiation was 72.8 years (IQR, 65.7-77.8), 128 (62.4%) were male, and 111 (63.4%) were Binet stage B/C at treatment initiation out of 175 with available information regarding clinical stage. Thirty-nine (19.0%) received ibrutinib as first-line, and 166 for R/R CLL with a median of 2 (range, 1-8) prior treatment regimens. Information on TP53 aberration was available for 149 and regarding IGHV mutation for 147 patients, 111 (74.5%) had TP53 aberration and 107 (72.8%) were IGHV unmutated. Eighty-six patients (42.0%) discontinued ibrutinib during follow-up with a median time until discontinuation of 9.3 months (IQR, 3.0-23.2). Forty-seven (54.7%) discontinued due to AEs, 19 (22.1%) due to progression (12 had progression of CLL and 7 had Richter's transformation) while the remaining 20 (23.2%) discontinued due to other reasons. The estimated cumulative incidence of discontinuation at 12 months was 24.8% (95% CI: 18.6-30.9). The estimated OS after 12 and 24 months was 88.8% (95%CI: 84.3-93.3) and 76.8% (95%CI: 70.4-83.2) and the estimated PFS after 12 and 24 months was 87.3% (95%CI: 82.5-92.1) and 72.4% (95%CI: 65.5-79.2). One hundred and eighty-eight (91.7%) experienced at least one AE, among these 45 (23.9%) experienced a grade 3+. The most common AEs were hemorrhage (tendency to bruise, epistaxis etc.) which occurred in 86 (42.0%) of all and musculoskeletal and connective tissue disorders (arthralgia, myalgia etc.) which occurred in 82 (40.0%). Thirty-one (15.1%) patients experienced atrial fibrillation while on ibrutinib and 14 (6.8%) developed hypertension. One hundred and thirty-seven patients (66.8%) had at least one infection and among these 80 (58.4%) were hospitalized with an infection. The most common infections were lower respiratory tract infections and urinary tract infections that occurred for 88 (42.9%) and 41 (20.0%). The estimated cumulative incidence for any infection was 58.9% (95%CI: 52.0-65.9) at 12 months. Conclusion This is the first study describing outcomes for a population-based cohort of CLL patients treated with ibrutinib in Denmark. Real-world studies are warranted, to confirm the results from clinical trials. In this study, patients appear to have comparable OS and types of AE compared with the RESONATE trial. Differences in frequency of AEs compared to the clinical trial may reflect the focus of clinicians in routine practice. Discontinuation in this cohort was higher compared to clinical trials but comparable to previously reported real-world studies. While ibrutinib can be safely managed in routine clinical practice, this study demonstrates that a quarter of patients discontinue treatment due to mainly AEs. Further patient training and information, and in some instances personalized treatment with other targeted agents based on adverse event profile, may improve treatment adherence. Disclosures Aarup: Research Committee, Rigshospitalet: Research Funding. Enggaard:Abbie: Other: Advisory board; Gilead: Other: Advisory board; Janssen: Other: Advisory board. Frederiksen:Gilead: Research Funding; Abbvie: Research Funding; Janssen Pharmaceuticals: Research Funding; Novartis: Research Funding; Alexion: Research Funding. Niemann:Novo Nordisk Foundation: Research Funding; AstraZeneca: Consultancy, Other: Travel Grant, Research Funding; Sunesis: Consultancy; Acerta: Consultancy; CSL Behring: Consultancy; Roche: Other: Travel Grant; Janssen: Consultancy, Other: Travel Grant, Research Funding; Gilead: Other: Travel Grant; Abbvie: Consultancy, Other: Travel Grant, Research Funding.

Description: Introduction In chronic lymphocytic leukemia (CLL), few randomized clinical trials include patients who are older or have significant comorbidity, despite constituting a large proportion of the CLL-population. Therefore, detailed data on the association of specific comorbidities with CLL-prognosis are missing and decisions on treatment and follow-up are poorly informed in comorbid patients. We present data on the association of comorbidity with prognostic factors, treatment patterns and causes of death in patients from the world's largest cohort of unselected CLL-patients. Methods All patients diagnosed with CLL in the CLL-registry (2008-2017) or the Danish Cancer Register (1997-2017) were followed through the Civil Registration System from 1 month after CLL-diagnosis until death, emigration or January 2017. Data from Danish nationwide population-based health registers were linked through personal unique identification numbers. Data on comorbidities based on the modified Charlson Comorbidity Index was attained from the Danish National Patient Register, from 20 years prior to the CLL-diagnosis and until 1 month after. Multimorbidity was defined as ≥ 2 comorbidities. Prognostic baseline data such as Binet Stage, IGHV-status, cytogenetics and β2-microglobuline (B2M) level were available through the CLL-registry. Causes of death were ascertained through the National Register of Causes of Death, further sub-categorized as CLL-related (including CLL, all other malignancies and infections) and CLL-unrelated death. Hazard ratios (HR) for mortality were calculated using Cox regression models, adjusting for age, sex, calendar period (5-year intervals) and internally for all other comorbidities. The association between IGHV-status and overall survival (OS) and treatment-free survival (TFS) was assessed by means of Kaplan-Meier and fully adjusted Cox models, stratifying for age and comorbidity-burden. Results The study included 8055 patients with a median follow-up time of 4.2 years; 59 % were male and the median age at diagnosis was 71 years. Overall 2816 patients (35%) were comorbid and 965 (12%) multimorbid. At diagnosis 818 (10%) patients had a history of chronic heart failure or myocardial infarction, 672 (8%) cerebrovascular disease, 626 (8%) diabetes (type 1 or 2), 620 (8%) chronic pulmonary disease, 399 (5%) peripheral vascular disease, 307 (4%) peptic ulcer, 264 (3%) connective tissue disease, 172 (2%) psychiatric disease, 148 (2%) renal disease, 87 (1%) dementia and 86 (1%) hepatic disease. Elevated B2M (〉4.0 mg/L) was more common in comorbid (20%) and multimorbid (24%) patients compared with non-comorbid (11%), while Binet Stage B/C, unmutated IGHV-status and del(17p) were evenly distributed across the groups (18-20%, 31-33% and 6-8%, respectively). Among comorbid patients, 56% died during follow-up, compared with 42% among non-comorbid patients. For comorbid patients, death was more commonly caused by cardiovascular disease (14% vs 6%) or other causes (14% vs 10%), while hematological malignancy was less common (25% vs 34%) compared with non-comorbid patients. Other malignancies (11% vs 13%), infection (34% vs 35%) and cerebrovascular disease (2% vs 2%) were equally common causes of death in the two groups. All individual comorbidities were associated with increased all-cause mortality. Except for connective tissue disease, dementia and chronic pulmonary disease, all comorbidities were associated with increased CLL-related mortality (Fig 1A) and as for CLL-unrelated mortality, only ulcer disease, psychiatric disease, renal disease and connective tissue were not associated with an increase. Unmutated IGHV status was associated with inferior TFS for all patients regardless of age and comorbidity burden (range of HRs 1.47-3.70), while IGHV status was associated with inferior OS for non-comorbid patients only (range of HRs 1.43-1.66). Of comorbid patients who died from CLL-related causes, 59% had not received treatment for CLL, compared with 43% among non-comorbid patients. Conclusions All individual types of comorbidity were associated with increased all-cause mortality and most also with higher CLL-related mortality. Improved management is warranted for comorbid CLL-patients, who should be prioritized in clinical trials of agents with high tolerability to further inform treatment guidelines and reduce CLL-related mortality for these patients. Disclosures Curovic Rotbain: Abbvie: Other: Travel Grant; AstraZeneca: Consultancy, Research Funding; Janssen: Research Funding. Niemann:Novo Nordisk Foundation: Research Funding; AstraZeneca: Consultancy, Other: Travel Grant, Research Funding; Sunesis: Consultancy; Acerta: Consultancy; CSL Behring: Consultancy; Roche: Other: Travel Grant; Janssen: Consultancy, Other: Travel Grant, Research Funding; Abbvie: Consultancy, Other: Travel Grant, Research Funding; Gilead: Other: Travel Grant. Da Cunha-Bang:Janssen: Consultancy; Abbvie: Consultancy, Other: Travel Grant; AstraZeneca: Consultancy; Roche: Other: Travel Grant. Frederiksen:Gilead: Research Funding; Abbvie: Research Funding; Janssen Pharmaceuticals: Research Funding; Novartis: Research Funding; Alexion: Research Funding.

Description: BACKGROUND: The WHO and iwCLL diagnostic criteria for CLL rely on morphology and immunophenotype based on the co-expression of CD19/CD5/CD23 on B-cells with weak CD20 and monoclonal sIg expression. These diagnostic criteria are likely to persist in the near future because there is no specific diagnostic molecular abnormality for CLL. The current criteria have some limitations affecting reproducibility, particularly flexibility in marker expression with many centres using a scoring system that permits absence of CD5 or CD23. Potentially informative new markers have been identified but there is no consensus yet on which should be routinely assessed. AIM: To identify reproducible criteria and to achieve a consensus on markers recommended for the diagnosis of CLL METHODS: ERIC/ESCCA members were invited to classify 35 flow-cytometry markers as being required or recommended for the diagnosis of CLL. Consensus was considered to be achieved if 〉75% of participants agreed on the marker classification. A diagnostic panel was identified by the steering committee and characteristics of component markers that could be reproducibly validated within an individual laboratory were identified. The proposed panel was assessed in 13 different centres. RESULTS: Responses were received from 154 members (100 laboratory staff, 14 clinicians and 36 from both laboratory and clinic) with a diagnostic workload 〉20 cases per week in 23/154 (15%), 5-20 in 82/154 (53%) and

Description: Introduction: BTK is involved in B-cell receptor (BCR) signal transduction and is an established target for the treatment of chronic lymphocytic leukemia (CLL) (Byrd, NEJM, 2013). ACP-196 is a novel, potent second generation BTK inhibitor, which binds covalently to Cys481 in the ATP-binding pocket of BTK. IC50determinations on nine kinases with a cysteine in the same position as BTK showed ACP-196 to be more selective than the first-in-class BTK inhibitor, ibrutinib (Covey, AACR, 2015). We present data evaluating the anti-tumor effects of ACP-196 in established murine models of CLL. Methods: Two distinct murine models were used for these studies. In the TCL1 adoptive transfer model, leukemic cells from Eμ-TCL1 transgenic mice were transplanted into C57BL/6 mice, resulting in a CD5+/CD19+ leukemia with peripheral blood, spleen and nodal involvement. ACP-196 treatment in drinking water (0.16 mg/mL) commenced when recipient mice had 〉 10% CD5+/CD19+ leukocytes in the peripheral blood. Mice were followed for survival. Separate cohorts were sacrificed for pharmacodynamic analyses after 1 and 4 weeks of treatment. In the second model, NSG mice received primary human CLL cells. The xenografted human CLL cells have comparable tumor biology (including active BCR signaling) to activated human lymph node resident CLL cells (Herman, Leukemia, 2013). PBMCs harvested from CLL patients were adoptively transferred at 1 x 108 cells per mouse. ACP-196 was initiated on day -1 (at the time of busulfan priming) at multiple doses ranging from 0.006 to 0.3 mg/mL in drinking water. Results: In the TCL1 model, treatment with ACP-196 showed 〉 90% BTK occupancy of BTK after 1 and 4 weeks of therapy. ACP-196 inhibited BCR signaling as shown by decreased autophosphorylation of BTK and reduction in surface expression of the BCR activation markers CD86 and CD69. After 1 week of ACP-196 inhibited BCR signaling as shown by a 6-fold reduction of autophosphorylation of BTK in the presence of anti-IgM, and surface expression of the BCR activation markers CD69 and CD86 were decreased by 47% and 57% respectively. Inhibition of BTK and downstream BCR activation was maintained through at least day 28 of treatment. Most notably, ACP-196 treatment resulted in a significant increase in survival compared with mice receiving vehicle (median 81 vs 59 days, respectively; P =0.02). In the NSG xenograft model, ACP-196 at the times examined did not cause a significant treatment-induced lymphocytosis in the patients evaluated (n=6). After 4 weeks of treatment with ACP-196, the NSG mice were sacrificed, and BCR signaling activity and tumor burden in the spleen were evaluated. ACP-196 treatment showed decreases in phosphorylation of PLCγ2 and ERK (P

Description: Background The treatment of chronic lymphocytic leukemia (CLL) is in rapid transition. As single agents, Fludarabine (F) was shown to be superior to chlorambucil (Rai, NEJM, 2000). Soon after F with Cyclophosphamide (C), showed superiority to F alone (Eichhorst, Blood, 2006; Flinn, JCO, 2007, Catovsky, Lancet, 2007). Subsequently, the addition of CD20 antibody rituximab (R) to FC for the first time showed a survival benefit for fit patients in a clinical trial (Hallek, Lancet, 2010). Likewise, in unfit patients the addition of CD20 antibodies to chlorambucil led to increased overall survival (Goede, NEJM, 2014). Eventually, BCR-targeted treatment for patients harboring TP53 aberrations demonstrated promising results (Farooqui, Lancet Onc, 2015). Here we assess the impact of these successive changes of therapy on the survival of patients with CLL in a Danish population-based cohort. Methods We studied the survival of a population-based cohort of CLL patients reported to the Danish Cancer Registry 1978-2013. Patients were categorized according to year of diagnosis from 1978-1994, 1995-2000, 2001-2005 and 2006-2013. For each CLL patient, we randomly selected 50 controls from the general population matched on age, gender and municipality. Kaplan MeierÕs survival curves and Hazard ratios (HR) and 95% confidence interval (95%CI) for death since time of diagnosis /matching date for controls were calculated. Change in survival probability relative to the controls with stratification on gender, age and calendar period of diagnosis was assessed. Results In total, 10500 patients were diagnosed with CLL in Denmark from 1978 to 2013 as follows: 1978-1994: 4651, 1995-2000: 1622, 2001-2005: 1664 and 2006-2013: 2563. Thus, the reported incidence of CLL increased slightly after year 2000. Overall, we observed a continuously decreasing risk of death for patients with CLL compared to matched controls, with HRs from 3.47 (3.37 - 3.58) to 2.09 (1.96 - 2.24) for patients diagnosed 1978-1994 and 2005-2013, respectively. In inter group analyses, a significant stepwise reduction in risk of death was observed for each period (Figure 1). In all age groups and calendar periods, male patients had an inferior survival compared to female patients and younger patients survived longer than older patients (p

Description: Background Patients with Chronic Lymphocytic Leukemia (CLL) have an increased risk of infections both prior to and upon treatment. Infections are the major cause of death for these patients, the 5-year incidence of severe infection prior to treatment is approximately 32 % with a 30-day mortality of 10 % (Andersen et al., Haematologica, 2018). Chemoimmunotherapy is still 1st line standard of treatment for patients without del17p or TP53 mutation despite association with neutropenia, immunesuppression and infections. The combination of BTK inhibitors and the bcl-2 inhibitor venetoclax has demonstrated synergy in vitro and in vivo, while translational data indicate that the CLL-related immune dysfunction can be improved on treatment with reduced risk of infections. Employing the Machine-Learning based CLL treatment infection model (CLL-TIM) that we have developed, patients with a high (〉65%) risk of infection and/or need of CLL treatment within 2 years of diagnosis can be identified (CLL-TIM.org). The significant morbidity and mortality due to infections in treatment-naïve CLL warrants trials that challenge the dogma of only treating symptomatic CLL. Thus, we initiated the randomized phase 2 PreVent-ACall trial of 12 weeks acalabrutinib + venetoclax to reduce risk of infections. Methods Design and statistics A phase 2, randomized, open label, multi-center clinical trial for newly diagnosed patients with CLL. Based on the CLL-TIM algorithm, patients with high risk of severe infection and/or treatment within 2 years from diagnosis can be identified. Approximately 20% of newly diagnosed CLL patients will fall into this high-risk group. First patient in trial planned for September 2019, primary outcome expected in 2021. Only patients identified as at high risk, who do not currently fulfil IWCLL treatment criteria are eligible. Patients will be randomized between observation in terms of watch&wait according to IWCLL guidelines or treatment. Primary endpoint Grade ≥3-Infection-free survival in the treatment arm compared to the observation arm after 24 weeks (12 weeks after end of treatment). Study treatment Acalabrutinib 100 mg BID from cycle 1 day 1 for 12 weeks. Venetoclax, ramp up during the first five weeks starting cycle 1 day 1, thereafter 400 mg once daily for a total of 12 weeks counted from cycle 1 day 1. Patients A sample size of 25 patients in each arm, 50 patients in total. Major inclusion criteria CLL according to IWCLL criteria ≤1 year prior to randomizationHigh risk of infection and/or progressive treatment within 2 years according to CLL-TIM algorithmIWCLL treatment indication not fulfilledAdequate bone marrow functionCreatinine clearance above 30 mL/min.ECOG performance status 0-2. Major exclusion criteria Prior CLL treatmentRichter's transformationPrevious autoimmune disease treated with immune suppressionMalignancies other than CLL requiring systemic therapies or considered to impact survivalRequirement of therapy with strong CYP3A4 and CYP3A5 inhibitors/inducers or anticoagulant therapy with vitamin K antagonistsHistory of bleeding disorders, current platelet inhibitors / anticoagulant therapyHistory of stroke or intracranial hemorrhage within 6 months Trial registry number EUDRACT NUMBER: 2019-000270-29 Clinicaltrials.gov number: NCT03868722 Perspectives: As infections is a major cause of morbidity and mortality for patients with CLL prior to any treatment, we aim at changing the natural history of immune dysfunction in CLL. The PreVent-ACaLL trial includes an optional extension into a phase 3 part with the primary outcome of grade ≥3 infection-free, CLL treatment-free survival two years after enrollment to address the unmet need of improved immune function in CLL for the first time. Figure Disclosures Da Cunha-Bang: AstraZeneca: Consultancy; Janssen: Consultancy; Abbvie: Consultancy, Other: Travel Grant; Roche: Other: Travel Grant. Levin:Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Educational grant ; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Educational grant . Österborg:BeiGene: Research Funding; Gilead: Research Funding; Janssen: Research Funding; Abbvie: Research Funding; Kancera AB: Research Funding. Niemann:Novo Nordisk Foundation: Research Funding; Gilead: Other: Travel grant; Janssen: Consultancy, Other: Travel grant, Research Funding; Roche: Other: Travel grant; CSL Behring: Consultancy; Acerta: Consultancy, Research Funding; Sunesis: Consultancy; Astra Zeneca: Consultancy, Research Funding; Abbvie: Consultancy, Other: Travel grant, Research Funding. OffLabel Disclosure: acalabrutinib and venetoclax in combination for CLL.

Description: Background Richter's transformation (RT) refers to the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL). Roughly, 2-10 % of patients with CLL develop RT most often as diffuse large B-cell lymphoma (DLBCL) or Hodgkin lymphoma (HL). Aim This study aimed to assess the incidence rate and risk factors for RT for patients with CLL in a nationwide cohort. Furthermore, we want to assess prognostic risk factors for patients with RT. Methods All patients diagnosed with CLL in Denmark between 2008 and 2016 were included in this study. Clinical data was retrieved from the Danish National CLL Registry (DCLLR), whereas all histologically verified DLBCL, HL and/or transformation diagnoses for patients with CLL were retrieved from the Danish National Pathology Registry. Patients were followed from date of CLL diagnosis until date of RT, death or end of follow-up, whichever came first. The time to RT was estimated as cumulative incidence considering death as a competing risk. Stepwise Cox analysis with backward elimination was applied to identify independent risk factors for RT in patients with CLL. Results A total of 3771 CLL patients were identified, and followed for 14165 person-years. With a median follow-up of 4.3 (IQR (2.4;6.6)) years, 120 (3%) CLL patients had a transformation diagnosis, of which 4 patients were excluded due to misdiagnosis. DLBCL accounted for 78/116 (67%) cases, HL for 15/116 (13%) cases and one patient presented with both DLBCL and HL. In the remaining 22/116 (19%) cases the subtype of the transformation was either unspecified or unclassified RT. The median time to RT was 3.4 (IQR (1.8;5.7)) years from CLL diagnosis and the median overall survival (OS) after development of RT was 4.9 (IQR (0.7;8.4)) years. The cumulative incidence of RT, calculated by Aalen-Johansen estimator, at 5 and 8 years post-CLL diagnosis were 3.3% and 7.9% respectively (Figure 1). The annual crude incidence rate of RT was approximately 0.7% per year for all CLL patients. In all, 918 (24%) patients received CLL-related treatment, of whom 59 (6.4%) patients developed RT, resulting in a cumulative incidence of RT of 7% after 5 years and 11% after 8 years. At the time of CLL diagnosis, patients treated for CLL prior to RT diagnosis had a worse median OS (1.49 years) compared to RT patients who were untreated for CLL (6.16 years). In the univariate analysis, RT was significantly associated with male gender, advanced Binet stage (B or C), unmutated IGHV status (CLL-U), elevated beta-2-microglobulin (〉3.5 mg/L) and elevated lactate dehydrogenase (〉205 U/L). Of cytogenic aberration, deletion 13q (del(13q)) had a protective effect on the risk of RT, whereas deletion 11q (del(11q)) and deletion 17p (del(17p)) increased the risk. In the multivariable model, advanced Binet stage (HR 2.86 (1.82;4.51), p