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Objectives: To examine perceptions of nurses and physicians in regard to ethical decision-making climate in the ICU and to test the hypothesis that the worse the ethical decision-making climate, the greater the discordance between nurses’ and physicians’ rating of ethical decision-making climate with physicians hypothesized to rate the climate better than the nurses. Design: Prospective observational study. Setting: A total of 68 adult ICUs in 13 European countries and the United States. Subjects: ICU physicians and nurses. Interventions: None. Measurements and Main Results: Perceptions of ethical decision-making climate among clinicians were measured in April-May 2014, using a 35-items self-assessment questionnaire that evaluated seven factors (empowering leadership by physicians, interdisciplinary reflection, not avoiding end-of-life decisions, mutual respect within the interdisciplinary team, involvement of nurses in end-of-life care and decision-making, active decision-making by physicians, and ethical awareness). A total of 2,275 nurses and 717 physicians participated (response rate of 63%). Using cluster analysis, ICUs were categorized according to four ethical decision-making climates: good, average with nurses’ involvement at end-of-life, average without nurses’ involvement at end-of-life, and poor. Overall, physicians rated ethical decision-making climate more positively than nurses (p < 0.001 for all seven factors). Physicians had more positive perceptions of ethical decision-making climate than nurses in all 13 participating countries and in each individual participating ICU. Compared to ICUs with good or average ethical decision-making climates, ICUs with poor ethical decision-making climates had the greatest discordance between physicians and nurses. Although nurse/physician differences were found in all seven factors of ethical decision-making climate measurement, the factors with greatest discordance were regarding physician leadership, interdisciplinary reflection, and not avoiding end-of-life decisions. Conclusions: Physicians consistently perceived ICU ethical decision-making climate more positively than nurses. ICUs with poor ethical decision-making climates had the largest discrepancies.

Abstract Introduction: Outcomes of multidisciplinary and molecular tumor boards have been reported. Lymphoma specific tumor board outcomes have not been reported in the molecular era. In addition, the utility of multi-site, interactive tumor boards using videoconference technology are not widely reported. We prospectively followed the outcomes of a multidisciplinary multi-site lymphoma tumor board in the molecular era and during a change in the revision of the World Health Organization Classification in first published in 2016. Methods: The Mayo Clinic Lymphoma Tumor Board is a component of the international Mayo Clinic Care Network (MCCN). The format includes the clinical case presentation, presentation of radiology and hematopathology findings by the appropriate specialist, proposed treatment options, review of the literature pertinent to the case, and discussion followed by recommendations. Requirement for presentation includes having a diagnosis of lymphoma with pathology reviewed at Mayo Clinic, Rochester, MN (MCR). Pathology and radiology material, when relevant to the case, are required to be reviewed at MCR and presented by MCR pathologists/radiologists. Patients must be presented prospectively, and have active clinical issues or questions to be addressed. Four cases are presented per 60-minute meeting. 309 consecutive highly selected cases with a diagnosis of lymphoma were presented at the Mayo Clinic Lymphoma Tumor Board from 2014 to 2018. The pathology material was independently reviewed by the presenting hematopathologists and radiology material by the presenting radiologist. Participants are office based and included multiple members of the health care team which also incudes pharmacists, clinical research associates affiliated with lymphoma research, and physicians in training. Recommendations were prospectively tracked for changes in radiology interpretation, pathologic diagnosis, and treatment approaches. Actual follow-up of all patients after the meeting was not allowed in the MCCN. Participation in the meeting can be either via in-room attendance at MCR, video conference at a participating MCCN site, or via non-participatory live-stream online. Results: 309 cases were presented were presented from 2014-2018. 258 cases were from MCR, and 51 were not physically seen at MCR. 16 cases were presented at a subsequent meeting for further recommendations in the course of their disease after the initial presentation. 54% of patients presented had changes in some aspect of their care as a result of the meeting. Changes in radiologic interpretation occurred in 5 (1.6%) patients. The pathologic diagnosis changed in 27 (8.7%). Additional testing was recommended in 44 (14%). Clinical management changes were recommended in 90 (29%) cases. These included alterations in treatment approach in 43 (14%), change from undecided to pursuit of treatment 10 (3%), change from undecided regarding treatment approach to further diagnostic testing 4 (1.3%), change from observation to treatment 9 (3%), change from treatment to observation 4 (1.3%), and treatment to further tests in 2 (0.6%) Site in room average attendance (internal/external) was 16.8/8.6. Non-participatory live-stream attendance was not possible to track. In an annual electronic evaluation of this activity, 93% of the responders reported an improvement in knowledge and competence, and 100% recommended no changes to the format of the conference. Enhancements over time have included Continuous Medical Education credit, an in room microscope, and real-time radiology images. Selected cases will now be on line on an international web site. Conclusion: In this highly selected group of lymphoma cases from multiple sites over a 4-year period, 54% of the (167/309) case presentations resulted in changes to some aspect of care as a direct result of this tumor board. A multidisciplinary lymphoma tumor board approach was of value, efficacious, and meaningfully impacted lymphoma patients while substantially enhancing interdisciplinary interactions. Disclosures Ansell: Celldex: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Merck & Co: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding.

Abstract Background: The pivotal phase 3 ECHELON-1 study demonstrated superior efficacy of brentuximab vedotin plus doxorubicin, vinblastine and dacarbazine (A+AVD) versus doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) in patients with previously untreated advanced stage classical Hodgkin lymphoma (cHL) with a 2-year modified progression-free survival (mPFS) of 82.1% in the A+AVD group versus 77.2% in the ABVD group (Hazard Ratio=0.77; 95% confidence interval [CI] 0.60, 0.98; p=0.04). PN is a known toxicity associated with anti-mitotic agents, including vinblastine and the MMAE component of brentuximab vedotin. In the ECHELON-1 study, the incidence of any-grade PN events was 67% (442 of 662 patients) and 43% (286 of 659 patients) in the A+AVD and ABVD arms, respectively; the incidence of grade ≥3 PN was 11% and 2%, respectively. At the time of the initial analysis, 67% of A+AVD-treated patients had either resolution (43%) or improvement (24%) of PN events. A total of the 92% of ongoing PN events were grade 1 (64%) or grade 2 (29%). Here, we report rates of PN resolution and improvement in patients participating in the ECHELON-1 study after long-term follow-up. Methods: Patients with Stage III or IV cHL were randomized 1:1 to receive up to six cycles of A+AVD (n=664) or ABVD (n=670). Pre-existing PN was an exclusion factor at study entry. Peripheral neuropathy was determined on the basis of a standardized MedDRA query; patients who developed PN were monitored throughout the study and those with ongoing PN at end of treatment were followed for resolution or improvement during the post-treatment follow-up period; follow-up visits were scheduled for every 12 weeks ±1 week until 36 months, then every 6 months until study closure. PN resolution was defined as completely resolved and improvement was defined as improved by ≥1 grade from worst grade as of the latest assessment. Results: At the time of the primary analysis, 51% (226/442) and 61% (174/286) of patients in the A+AVD and ABVD arms, respectively, had resolution or improvement of PN events at EOT. Upon continued follow-up (~10 additional months) for approximately 30 months (range 0-78.5) after end of treatment, 76% (335/442) of patients with PN in the A+AVD arm had either complete resolution (59%, 260/442) or improvement (17%, 75/442) of their PN events compared with 82% (234/286) with either resolution (72%) or improvement (10%) in the ABVD arm. In the A+AVD arm, 90% of ongoing PN cases (n=182) were grade 1/2; grade 1=58% (n=106), grade 2=32% (n=58). Residual grade 3 PN was reported in 9% (n=17) of patients (1 patient with grade 4 PN died before resolution). In the ABVD arm, residual PN (n=81) was grade 1 (65%; n=53), grade 2 (30%; n=24), and grade 3 (5%; n=4). For the subset of patients with PN that had not resolved by end of treatment, the median time to resolution of all PN events from AE start date was 28 weeks for A+AVD and 14 weeks for ABVD, the median time to improvement of PN was 39 weeks for A+AVD and 18.5 weeks for ABVD. Conclusions: After approximately 2.5 years of continued follow-up, PN continues to resolve and improve for patients who were treated with A+AVD or ABVD in the ECHELON-1 study. In both study arms, the majority of ongoing PN cases are grade 1 or grade 2. Further follow-up is ongoing. Disclosures Radford: Celgene: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Speakers Bureau; GlaxoSmithKline: Equity Ownership; Takeda: Consultancy, Research Funding, Speakers Bureau; Pfizer: Research Funding; BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; AstraZeneca: Equity Ownership. Connors:Takeda: Research Funding; Seattle Genetics: Honoraria, Research Funding; Roche Canada: Research Funding; Genentech: Research Funding; Cephalon: Research Funding; Bristol Myers-Squibb: Research Funding; Janssen: Research Funding; Bayer Healthcare: Research Funding; NanoString Technologies: Patents & Royalties: Named Inventor on a patent licensed to NanoString Technologies, Research Funding; Merck: Research Funding; F Hoffmann-La Roche: Research Funding; Amgen: Research Funding; Lilly: Research Funding. Younes:Astra Zeneca: Research Funding; J&J: Research Funding; Curis: Research Funding; BMS: Honoraria, Research Funding; Bayer: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Merck: Honoraria; Seattle Genetics: Honoraria; Celgene: Honoraria; Incyte: Honoraria; Abbvie: Honoraria; Novartis: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding. Gallamini:Takeda: Consultancy, Speakers Bureau. Ansell:Affimed: Research Funding; Merck & Co: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Bristol-Myers Squibb: Research Funding; Celldex: Research Funding; Seattle Genetics: Research Funding. Gopal:Aptevo: Consultancy; Janssen: Consultancy, Research Funding; Merck: Research Funding; Gilead: Consultancy, Research Funding; Brim: Consultancy; Spectrum: Research Funding; Takeda: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Seattle Genetics: Consultancy, Research Funding; Incyte: Consultancy; Teva: Research Funding; Asana: Consultancy. Flinn:Trillium: Research Funding; Calithera: Research Funding; Forma: Research Funding; Portola: Research Funding; Verastem: Research Funding; Janssen: Research Funding; Infinity: Research Funding; Genentech: Research Funding; Forty Seven: Research Funding; Constellation: Research Funding; Merck: Research Funding; Curis: Research Funding; Takeda: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Incyte: Research Funding; ArQule: Research Funding; Verastem: Consultancy, Research Funding; Celgene: Research Funding; Agios: Research Funding; Novartis: Research Funding; Gilead: Research Funding; Pfizer: Research Funding; TG Therapeutics: Research Funding; Kite: Research Funding; BeiGene: Research Funding. Pettengell:CTI: Honoraria; Pfizer: Honoraria; Roche: Honoraria; Servier: Honoraria; Takeda: Honoraria. Dlugosz-Danecka:Servier: Consultancy; Roche: Consultancy. Engley:Seattle Genetics: Employment. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Liu:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Purevjal:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Miao:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Gautam:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Kuruvilla:Janssen: Consultancy, Honoraria, Research Funding; Princess Margaret Cancer Foundation: Research Funding; BMS: Consultancy, Honoraria; Abbvie: Consultancy; Karyopharm: Honoraria; Celgene: Honoraria; Seattle Genetics: Consultancy, Honoraria; Lundbeck: Honoraria; Merck: Consultancy, Honoraria; Amgen: Honoraria; Roche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria; Leukemia and Lymphoma Society Canada: Research Funding.

Abstract Abstract 4876 Background Recent studies have found obesity to be associated with a 1.5- to 2-fold elevated risk of developing multiple myeloma. This is of particular interest given that elevated levels of the pro-inflammatory cytokine interleukin (IL)-6 have been found in obese persons, and, at the same time, IL-6 has well-known proliferative and anti-apoptotic effects on monoclonal plasma-cells. Also insulin-like growth factors (IGFs) have been proposed to play a role since obesity often causes insulin resistance, which in turn modulates the bioavailability of IGF-1 Similar to IL-6, prior studies have found IGF-1 to have both growth and survival effects on monoclonal plasma-cells. Based on these facts, we have speculated that obesity might increase the risk of the multiple myeloma precursor monoclonal gammopathy of undetermined significance (MGUS), or, alternatively, that obesity may increase the risk for transformation from MGUS to multiple myeloma. We conducted the first large screening study designed to assess the association between obesity and MGUS among almost 2,000 African-American and Caucasian women. Methods We included 1000 African-American and 996 Caucasian women (age 40-79, median 48 years) from the Southern Community Cohort Study to assess MGUS risk in relation to obesity. Per our sampling strategy, about 50% of the participants were obese. Medical record-abstracted weight and height (measured on the day of study enrollment) and self-reported values had very high concordance (Pearson correlation >0.95). Serum samples from all subjects were analyzed by electrophoresis performed on agarose gel; samples with a discrete or localized band were subjected to immunofixation. Using logistic regression models, we estimated odds ratios (ORs) as measures of risk. Results Among all study participants, 39 (3.9%) African-Americans and 21 (2.1%) Caucasians were found to have MGUS, yielding a 1.9-fold (95%CI 1.1-2.3; p=0.021) higher risk of MGUS among African-Americans (vs. Caucasians). On multivariate analysis, we found obesity (OR=1.8, 95%CI 1.03-3.1; p=0.039), African-American race (OR=1.8, 95%CI 1.04-3.1; p=0.037), and increasing age (quartiles: ≥55 vs. <43 years) (OR=2.5, 95%CI 1.1-5.7; p=0.028) to be independently associated with an excess risk of MGUS. Another interesting finding was that the distribution of the monoclonal immunoglobulin isotype usage among African-American and Caucasian women was significantly different (p=0.007). Their respective rates were: IgG in 79.5% and 71.3 %; IgA in 7.7% and 0%; IgM in 7.7% and 19%; biclonal in 5.1% and 4.7%; and triclonal in 0% and 4.7%. The distribution of serum light-chain types between the two races was also significantly different (P=0.003, chi-square test): kappa in 53.8% and 47.6%; lambda in 43.6% and 42.8%; biclonal 2.6% and 4.7%; and triclonal in 0% and 4.7%. Conclusions Our finding that MGUS is twice as common among obese (vs. non-obese) women, and independent of race, supports the hypothesis that obesity is etiologically linked to myelomagenesis and may have public health impact. The observed 2-fold excess of MGUS among African-Americans (vs. Caucasians) of similar socio-economic status, coupled with other recent studies supports a role for susceptibility genes as the cause for racial disparity in the prevalence of MGUS. Disclosures No relevant conflicts of interest to declare.

Abstract Arabinosyl cytosine (ara-C), a synthetic pyrimidine nucleoside related to the normal metabolites cytidine and deoxycytidine, has been found capable of producing marrow remission at tolerable doses in acute myelocytic and acute lymphocytic leukemia in adults. There were 16 per cent remissions complete in all aspects, 3 per cent complete except for hemoglobin level, and 6 per cent partial remissions among 180 adults with acute myelocytic leukemia treated with any one of 8 variants of infusion duration or daily dose of ara-C. Twenty-four per cent of 37 adults with acute lymphocytic or unclassified leukemia had complete or partial remissions. The comparison of 1, 4, 12 and 24 hours infusion of ara-C (to total dose tolerated) does not show significant superiority for any one group. The complete remission rate with 1 or 12 hour infusions, however, is 25 per cent (superior to that obtained with 6-mercaptopurine) and the recommended schedule of treatment for ara-C based on these data is, therefore, daily infusions of 100 or 50 mg./m.2 in one hour for approximately 3 to 6 weeks followed by maintenance therapy of once weekly subcutaneous injection of 30 mg./m.2 of ara-C. Platelet transfusions should be available when ara-C is used.

AbstractBackgroundThe extent to which obesity and genetics determine postoperative complications is incompletely understood.MethodsWe performed a retrospective study using two population cohorts with electronic health record (EHR) data. The first included 736,726 adults with body mass index (BMI) recorded between 1990 and 2017 at Vanderbilt University Medical Center. The second cohort consisted of 65,174 individuals from 12 institutions contributing EHR and genome‐wide genotyping data to the Electronic Medical Records and Genomics (eMERGE) Network. Pairwise logistic regression analyses were used to measure the association of BMI categories with postoperative complications derived from International Classification of Disease‐9 codes, including postoperative infection, incisional hernia, and intestinal obstruction. A genetic risk score was constructed from 97 obesity‐risk single‐nucleotide polymorphisms for a Mendelian randomization study to determine the association of genetic risk of obesity on postoperative complications. Logistic regression analyses were adjusted for sex, age, site, and race/principal components.ResultsIndividuals with overweight or obese BMI (≥25 kg/m2) had increased risk of incisional hernia (odds ratio [OR] 1.7–5.5, p < 3.1 × 10−20), and people with obesity (BMI ≥ 30 kg/m2) had increased risk of postoperative infection (OR 1.2–2.3, p < 2.5 × 10−5). In the eMERGE cohort, genetically predicted BMI was associated with incisional hernia (OR 2.1 [95% CI 1.8–2.5], p = 1.4 × 10−6) and postoperative infection (OR 1.6 [95% CI 1.4–1.9], p = 3.1 × 10−6). Association findings were similar after limitation of the cohorts to those who underwent abdominal procedures.ConclusionsClinical and Mendelian randomization studies suggest that obesity, as measured by BMI, is associated with the development of postoperative incisional hernia and infection.

Abstract Introduction Diffuse or polyclonal hypergammaglobulinemia has been associated with multiple medical conditions such as autoimmune diseases, infections, and chronic liver diseases. However, the possibility of differences in gamma globulin levels in different races and its association with environmental and socioeconomic factors is not well studied. Method A randomized sample of 917 adult males (50–74 years) in an urban community in Ghana underwent in-person interview and health examination. Serum from all persons was analyzed by electrophoresis performed on agarose gel. Those found to have a monoclonal protein (n=54) were excluded from further analysis. Gamma globulin levels were measured in the remaining 863 samples. Associations between selected characteristics and gamma globulin levels were assessed by Chi-square test and logistic regression models. Results The median gamma globulin level was 1.86 gm/dl. Seventy three percent of the study population had gamma globulin levels above the 1.6 gm/dl reference level and will be considered to have hypergammaglobulinemia. Surprisingly, 25% had gamma globulin levels above 2.17 gm/dl. In univariate analysis increased gamma globulin levels were associated with older age within the study population. Only 54% of the males aged 60 yrs or younger had gamma globulin levels above 1.6 gm/dl compared to 69% in those older than 60 yrs (p=0.007). Higher education level was associated with a low prevalence of hypergammaglobulinemia 51% compared with 74% in those with less than high school education (p <0.0001). Smoking was not associated (p=0.16) with gamma globulin levels. Although a higher proportion (71%) of people with history of alcohol use had hypergammaglobulinemia compared to the control (63%) this was not statistically significant (p=0.07). Self-reported history of genital warts, genital herpes and meningitis was associated with hypergammaglobulinemia, whereas syphilis, malaria, cholera, gonorrhea, hepatitis, measles and tuberculosis had no association with gamma globulin levels in univariate analysis. Conclusion Three quarters of this randomized sample of Ghanaian adult males has hypergammaglobulinemia based on current laboratory definitions. More work is needed to uncover underlying causes for the observed high gamma globulin levels in this population. Further evaluation of a younger population with less environmental influence may help explain whether this is due to genetic differences, environmental exposures, or a combination.

Abstract Background Rituximab in combination with chemotherapy has been shown to improve overall survival (OS) in pts with FL compared with chemotherapy alone. The effect of MR was evaluated in randomized clinical trials (RCTs) with conflicting results regarding OS. In a previous systematic review and meta-analysis of summary (aggregate) data we demonstrated an OS benefit of MR treatment in pts with relapsed or refractory FL and an improved progression free survival (PFS) in both untreated and relapsed refractory FL. However, pts' disease and treatment characteristics may interact with the effect of MR. To improve identification of sub-groups of pts who may benefit from MR treatment, and to evaluate factors that interact with the effect of MR we conducted an international IPD (raw data) meta-analysis of RCTs of MR for pts with FL. We present the first analysis of this meta-database. Methods In June 2014, we updated an electronic search in Pubmed and the Cochrane Library, conference proceedings and database of clinical trials for randomized trials comparing MR to observation. The investigators of eleven trials that fulfilled inclusion criteria were invited to cooperate. Results of one trial were not reported and this trial could not be included in the meta-analysis. Seven study groups participated in this collaborative project and contributed data on individual pts, including disease characteristics, past treatment, response, survival and adverse events. We examined the effect of pt, disease and treatment characteristics by performing a series of Cox regression analyses stratified by trial. In a sensitivity analysis we combined the assessed log hazard ratios (HR) using a log-rank test for each study and combined the results using a fixed effect meta-analysis. Results We obtained data for 2323 patients randomized in 7 trials of MR compared to observation after induction therapy. The median follow up ranged from 28-114 months. The median age was 57 years (23 - 85 years), and 41% were older than 60 years. 50% of pts were women, 97% had WHO performance status 0-1; 1195 (53%) pts received CHOP/RCHOP, 453 (20%) CVP/R CVP; 1755 (77%) received rituximab containing induction; 33% of pts received 1st induction, 67% ≥2nd. Overall, pts less than 60 years of age (vs. ≥60 years) (p < 0.0001), and women (p = 0.001) had a better prognosis. There was no interaction between sex and the effect of MR (p = 0.65). Pts treated with MR had an improved OS compared to observation (HR 0.76, 95% CI 0.62-0.93, p=0.008, Figure). This was demonstrated also in a sensitivity analysis of 10 studies fulfilling inclusion criteria. There was no statistically significant heterogeneity of treatment effect between trials (p=0.15). In an analysis by treatment line (1st vs. ≥2nd), the estimated effect of MR among patients who received ≥2nd induction was HR of 0.70 (95% CI 0.55 - 0.91), compared to 0.90 (95% CI 0.65 - 1.25) among patients who received 1st induction. However, this difference was not statistically significant (p=0.25). Analysis by the inclusion of rituximab in induction demonstrated among patients who received rituximab in induction a HR of 0.82 (95% CI 0.63 – 1.06), and among those who received induction without rituximab a HR of 0.68 (95% CI 0.49 – 0.93). This difference was not statistically significant (p= 0.35). Analysis by chemotherapy regimen demonstrated an estimated effect for MR among patients who received RCHOP/CHOP of 0.79, 95% CI 0.58 – 1.06, and after RCVP/CVP of 0.65, 95% CI 0.42 – 1.02, with no statistically significant difference between these sub-groups (p = 0.50). Conclusions This is the first report of the collaborative group of maintenance therapy for FL patients. Based on individual patient data, this study demonstrated an improved OS with MR therapy for patients with FL. A sensitivity analysis with all 10 eligible trials supported these results. Results support the effectiveness of MR among patients after their 1st induction as well as after ≥2nd induction, and irrespective of inclusion of rituximab in induction, and the chemotherapy regimen. These results are consistent with those of the summary data meta-analysis that was previously published. The wider CI and lack of statistical significance within sub-groups could be attributed to the sample size. Figure: Pooled HR of death of MR compared to observation in patients with follicular lymphoma. In one study there were no events in one group and it is not represented in the forest plot. Figure:. Pooled HR of death of MR compared to observation in patients with follicular lymphoma. In one study there were no events in one group and it is not represented in the forest plot. Disclosures Vidal: Roche: unrestricted grant Other. Shpilberg:Roche: Consultancy, Research Funding.

Abstract BACKGROUND. The detection of minimal residual disease (MRD) at the level of 0.01%/10-4 or above is a strong independent predictor of reduced progression-free (PFS) and overall survival (OS) in patients with CLL treated with chemoimmunotherapy. Although newer agents such as B-cell receptor pathway inhibitors can result in prolonged survival without achieving complete response, there remains a important role for MRD analysis in assessing therapeutic strategies aimed at disease eradication and cure. This is particularly important in front-line trials for fit patients which now require at least five years of follow-up if PFS is used as an endpoint. The feasibility of using MRD as a surrogate or intermediate endpoint for accelerated approval of new treatments is under review by regulatory agencies but further prospective validation is required. At the same time technology is rapidly evolving and high-throughput sequencing (HTS) technologies now detect MRD at the 0.0001%/10-6 level. It is therefore important to determine the most effective approaches for quantifying MRD that are compatible with previous studies but sufficiently sensitive for current treatments. AIMS. This collaborative project had two objectives. First, to identify the simplest and most flexible flow cytometry panel capable of detecting MRD at the 0.01%/10-4 or lower, that is compatible with published data and independent of instrument/reagent manufacturer. Second, to compare the flow cytometry approach with HTS analysis using the ClonoSEQ assay (Adaptive Biotechnologies, Seattle, WA). METHODS AND RESULTS. A core panel of antibodies for MRD detection was identified by testing an 8-marker combination in 52 samples (27 post-treatment and 25 dilution study) and re-analysing data with serial exclusion of single markers to determine redundancy. A 1-tube core panel of CD19, CD20, CD5, CD43, CD79b, and CD81 was identified and validated against the previously published 2-tube 6-marker and 4-tube 4-marker ERIC panels in 76 samples (19 post-treatment and 57 dilution study). The results showed good concordance (for log-transformed data above the LoQ, linearity=0.977, Pearson correlation co-efficient=0.983, average difference=0.026 log, 95% limit of agreement 0.20log) and a limit of detection of 0.001%/10-5 for the 1-tube core panel. Inter-operator variation was similar to CML MRD monitoring with both experienced operators, or inexperienced cytometrists after ~1 hour of specific education, achieving a 95% limit of agreement less than 0.3log in samples with MRD levels ranging from 0.0001 – 100%. The flow cytometry approach was compared with the ClonoSEQ HTS assay in 109 samples (21 dilution study and 88 post-treatment samples, complete data currently available on 13/88). The assay was applicable to the vast majority CLL patients, often with two clonal markers. There was 94% concordance at the 0.01% (10-4) threshold (15 samples with ≥0.01% CLL by both methods, 14 samples with <0.01% by both methods, 1 sample with 0.03% CLL by HTS and <0.003% CLL by flow cytometry, and 1 sample with 0.005% CLL by HTS and 0.012% by flow cytometry. HTS detected CLL IGH sequences in 22% (7/31) samples with no detectable CLL cells by flow cytometry (i.e. CLL level 0.0001-0.001%, 3/13 patient samples and 4/18 dilution samples). HTS demonstrated a relatively high variability in quantification, as seen in previous studies, but with a clear superiority in the limit of detection and good linearity (linearity=0.905, Pearson correlation co-efficient=0.870, average difference=0.078 log, 95% limit of agreement 1.5 log). CONCLUSIONS. The 1-tube 6-marker flow cytometry core panel is compatible with published studies, manufacturer-independent and flexible, providing directly quantitative results to 0.001%/10-5 without requiring a pre-treatment sample. HTS requires further work to standardise the quantitative analysis and prospective validation but the ClonoSEQ assay is applicable to >95% of CLL patients, does not require viable cells and is extremely sensitive, detecting residual disease in a significant proportion of cases with <0.01% CLL. The results indicate that flow cytometry and HTS are complementary technologies with a combined approach offering the most reliable way of quantifying CLL at the 0.01%/10-4 threshold while allowing higher sensitivity in clinical trials aimed at disease eradication. Disclosures Rawstron: Roche: Honoraria; Biogen Idec: Consultancy; Gilead: Consultancy, Honoraria; Abbvie: Honoraria; BD Biosciences: Intrasure reagent Patents & Royalties; Celgene: Honoraria; GSK: Honoraria. Williamson:Adaptive Biotechnologies: Employment, Equity Ownership. Sanders:Adaptive Biotechnologies: Employment, Equity Ownership. Robins:Adaptive Biotechnologies: Consultancy, Equity Ownership, Patents & Royalties. Hallek:Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GSK: Honoraria; Gilead: Honoraria. Hillmen:Roche: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria, Research Funding.