The rarity of neoplastic cells in the biopsy imposes major technical hurdles that have so far limited genomic studies in classical Hodgkin lymphoma (cHL). By using a highly sensitive and robust deep next-generation sequencing approach for circulating tumor DNA (ctDNA), we aimed to identify the genetics of cHL in different clinical phases, as well as its modifications on treatment. The analysis was based on specimens collected from 80 newly diagnosed and 32 refractory patients with cHL, including longitudinal samples collected under ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) chemotherapy and longitudinal samples from relapsing patients treated with chemotherapy and immunotherapy. ctDNA mirrored Hodgkin and Reed-Sternberg cell genetics, thus establishing ctDNA as an easily accessible source of tumor DNA for cHL genotyping. By identifying as the most frequently mutated gene in ∼40% of cases, we refined the current knowledge of cHL genetics. Longitudinal ctDNA profiling identified treatment-dependent patterns of clonal evolution in patients relapsing after chemotherapy and patients maintained in partial remission under immunotherapy. By measuring ctDNA changes during therapy, we propose ctDNA as a radiation-free tool to track residual disease that may integrate positron emission tomography imaging for the early identification of chemorefractory patients with cHL. Collectively, our results provide the proof of concept that ctDNA may serve as a novel precision medicine biomarker in cHL.

Key Points CLL patients harboring mutated IGHV genes but neither 11q or 17p deletion experience durable remission after frontline FCR.

IRC3 is a recurrently mutated gene in chronic lymphocytic leukemia (CLL) but the functional implications of BIRC3 mutations are largely unexplored. Furthermore, little is known about the prognostic impact of BIRC3 mutations in CLL cohorts homogeneously treated with first-line fludarabine, cyclophosphamide, and rituximab (FCR). By immunoblotting analysis, we showed that the non-canonical nuclear factor-κB pathway is active in BIRC3-mutated cell lines and in primary CLL samples, as documented by the stabilization of MAP3K14 and by the nuclear localization of p52. In addition, BIRC3-mutated primary CLL cells are less sensitive to fludarabine. In order to confirm in patients that BIRC3 mutations confer resistance to fludarabine-based chemoimmunotherapy, a retrospective multicenter cohort of 287 untreated patients receiving first-line FCR was analyzed

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W e present a laboratory-based prognostic calculator (designated CRO score) to risk stratify treatment-free survival in early stage (Rai 0) chronic lymphocytic leukemia (CLL) developed using a training-validation model in a series of 1,879 cases from Italy, the United Kingdom and the United States. By means of regression analysis, we identified five prognostic variables with weighting as follows: deletion of the short arm of chromosome 17 and unmutated immunoglobulin heavy chain gene status, 2 points; deletion of the long arm of chromosome 11, trisomy of chromosome 12, and white blood cell count >32.0x10 3 /microliter, 1 point. Low-, intermediate-and high-risk categories were established by recursive partitioning in a training cohort of 478 cases, and then validated in four independent cohorts of 144 / 395 / 540 / 322 cases, as well as in the composite validation cohort. Concordance indices were 0.75 in the training cohort and ranged from 0.63 to 0.74 in the four validation cohorts (0.69 in the composite validation cohort). These findings advocate potential application of our novel prognostic calculator to better stratify early-stage CLL, and aid case selection in risk-adapted treatment for early disease. Furthermore, they support immunocytogenetic analysis in Rai 0 CLL being performed at the time of diagnosis to aid prognosis and treatment, particularly in today's chemofree era.

Introduction: Observation is the standard of care for asymptomatic early stage chronic lymphocytic leukemia (CLL) however these cases follow a heterogenous course. Recent studies show novel biomarkers can delineate indolent from aggressive early stage disease and current clinical trials are exploring the role of early intervention in high risk cases. Although several scoring systems have been established in CLL, most are designed for overall survival, do not circumscribe early stage disease, and require cumbersome calculations relying on extensive laboratory and clinical information. Aim: We propose a novel laboratory-based prognostic calculator to risk stratify time to first treatment (TTFT) in early stage CLL and guide candidate selection for early intervention. Methods: We included 1574 cases of early stage CLL in an international cohort from Italy, the United Kingdom and the United States using a training-validation model. Patient information was obtained from participating centers in accordance with the Declaration of Helsinki. The training cohort included 478 Rai 0 cases from a multicenter Italian cohort, all referred to a single center (Clinical and Experimental Onco-Hematology Unit of the Centro Riferimento Oncologico in Aviano, IT) for immunocytogenetic lab analyses. Considering TTFT as an endpoint, we evaluated 8 variables (age>65, WBC>32K, 17p-, 11q-, +12, IGHV status, CD49d+, gender) with univariate and multivariate Cox regression internally validated using bootstrapping procedures. FISH thresholds were 5% for 11q-, and +12 and 10% for 17p-. Cases were categorized according to the hierarchical model proposed by Dohner. IGHV status was considered unmutated at ≥98%. CD49d+ was set at >30%. WBC cutoff of >32K was established by maximally selected log rank analysis. Variables were weighted based on the proportion of their normalized hazard ratios rounded to the nearest whole integer. We used recursive partitioning for risk-category determination and Kaplan-Meier analysis to generate survival curves. We compared the concordance index (C-index) of our model with the CLL international prognostic index (CLL-IPI) for 381/478 cases in the training cohort with available beta-2-microglobulin data and for all validation cohorts. We used 3 independent single-center cohorts for external validation. Results: The training cohort had 478 cases of Rai 0 CLL with a median (95% CI) TTFT of 124 months (m) (104-183m). Five prognostic variables emerged with respect to TTFT, and each assigned a point value of 1 or 2 according to their respective normalized HR values as follows: 17p-, and UM IGHV (2 pts); 11q-, +12, and WBC>32K (1 pt). We identified three risk groups, based on point cut-offs of 0, 1-2, and 3-5 established by recursive partitioning analysis with a median (95% CI) TTFT of 216m (216-216m), 104m (93-140m) and 58m (44-68m) (p<0.0001, C-index 0.75) for the low, intermediate, and high-risk groups, respectively (figure 1). A comparison with the CLL-IPI was possible in 381 cases with available beta-2-microglobulin data. In this subset, the C-index was 0.75 compared to 0.68 when patient risk groups were split according to the CLL-IPI. The scoring system was then validated in 3 independent cohorts of early stage CLL: i) Gemelli Hospital in Rome, IT provided 144 Rai 0 cases. Median (95% CI) TTFT was 86m (80-94m, 95% CI). Median (95% CI) TTFT for the low, intermediate and high-risk groups was 239m (239-239m), 98m (92-132m) and 85m (60-109m) respectively (p=0.002 between low and intermediate groups, p=0.09 between intermediate and high groups; C-index 0.64 v 0.60 for CLL-IPI). ii) Cardiff University Hospital in Wales, UK provided 395 Binet A cases. Median (95% CI) TTFT was 74 m (67-81m) overall and NR, 111m (97-146m) and 70m (29-114m) for the low, intermediate and high-risk groups respectively (p<0.001 between low and intermediate groups, p=0.009 between intermediate and high groups; C-index 0.63 v 0.63 for CLL-IPI). iii) Mayo Clinic in Rochester, MN provided 557 Rai 0 cases. Median (95% CI) TTFT was 127m (96m-NR) overall and NR, 76m (64m-NR) and 36m (31-59m) for the low, intermediate and high-risk groups respectively (p<0.0001; C-index 0.72 v 0.68 for CLL-IPI). Conclusion: We present a novel laboratory-based scoring system for Rai 0/Binet A CLL to aid case selection in risk-adapted treatment for early disease. Further comparison to existing indices is needed to verify its utility in the clinical setting. Disclosures Zaja: Novartis: Honoraria, Research Funding; Takeda: Honoraria; Abbvie: Honoraria; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Janssen: Honoraria; Sandoz: Honoraria. Fegan:Roche: Honoraria; Napp: Honoraria; Janssen: Honoraria; Gilead Sciences, Inc.: Honoraria; Abbvie: Honoraria. Pepper:Cardiff University: Patents & Royalties: Telomere measurement patents. Parikh:AstraZeneca: Honoraria, Research Funding; Janssen: Research Funding; MorphoSys: Research Funding; Abbvie: Honoraria, Research Funding; Gilead: Honoraria; Pharmacyclics: Honoraria, Research Funding. Kay:Janssen: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees.

Introduction Progression of disease within 2 years after starting rituximab-chemotherapy (POD24) has been identified as a convincing adverse prognostic factor for follicular lymphoma (FL), and can serve as a clinical endpoint to identify patients at high risk of early lymphoma-related mortality. However, POD24 is not accessible at diagnosis. Several stratification models adopting baseline variables have been developed for predicting outcomes in FL patients. The Follicular Lymphoma International Prognostic Index (FLIPI) and PRIMA Prognostic-Index (PRIMA-PI) include clinical characteristics, while m7- Follicular Lymphoma International Prognostic Index (m7-FLIPI) and POD24 Prognostic Index (POD24-PI) integrate gene mutations with clinical features. Moreover, the mutation status of specific genes (including TP53, EZH2, TNFRSF14, and BCL2) has been reported to be relevant to early progression. It has been reported that m7-FLIPI and POD24-PI are predictive for POD24. Here we compare the diagnostic accuracy for POD24 of various stratification models and gene mutations in an institutional cohort of FL. Methods Consecutive patients diagnosed as FL grades 1-3a were enrolled from the Oncology Institute of Southern Switzerland (n=75), the University of Eastern Piedmont (n=118), and the Hematology of the AUSL IRCCS of Reggio Emilia (n=59). DNA was extracted from FFPE tissue specimen obtained at diagnosis. We performed CAPP-seq to detect the mutation status of the genes included in m7-FLIPI and POD24 PI (EZH2,ARID1A, MEF2B, EP300, FOXO1, CREBBP, and CARD11), as well as BCL2, TNFRSF14 and TP53. POD24 was the primary endpoint of this research. Sensitivity, specificity, predictive values and balanced accuracy of every stratification model were calculated to estimate the prognostic efficacy. Results With FLIPI score, 34% of patients were classified as low risk, 22% as intermediate risk, and 41% as high risk. With PRIMA-PI, the fractions for low risk, intermediate risk and high risk group were 24%, 21% and 49%, respectively. With m7-FLIPI, 82% of patients were low risk, and 15% high risk. For POD24-PI, 65% of patients were low risk, and 32% high risk. The mutation frequencies of TP53, TNFRSF14, EZH2 and BCL2 were 8%, 28%, 27% and 38%, respectively. We validated the prognostic utility of FLIPI, PRIMA-PI, m7-FLIPI and POD24-PI for progression free survival (PFS) and OS. However, no statistically significant relevance with PFS or OS has been found for TP53, TNFRSF14, EZH2 or BCL2 mutations. POD24 was calculated in the 142 patients who received systemic treatment (immunotherapy or chemoimmunotherapy) within 6 months from diagnosis: 18% of them were POD24-positive. POD24 positivity associated with shorter overall survival (OS) (p=0.0138). After adjusting for multiple comparisons, no high-risk groups identified by TNFRSF14, EZH2 or BCL2 gene mutations, FLIPI, PRIMA-PI, m7-FLIPI or POD24-PI were associated with POD24. In terms of diagnostic performance for POD24, PRIMA-PI showed the highest accuracy (57%), FLIPI had the highest positive predictive value (64%), and m7-FLIPI had the highest negative predictive value (82%). Conclusion The mutation status of specific single genes were not related to POD24, PFS nor OS, indicating that the mutation of single gene may not be sufficient to identify high-risk FL patients. Though retaining their prognostic value, the integration of mutations onto the clinical biomarker-based prognostic scores has a limited discrimination capacity for POD24. Our results prompt the investigation of: i) POD discrimination capacity of prognostic models based on molecular phenotypes (i.e. gene expression) reflecting the tumor-microenvironment milieu; ii) new models based on a combination of biomarkers capturing the most informative clinical, genetic and phenotypic features. Figure 1 Disclosures Moccia: Takeda: Consultancy, Other: Advisory Boards: Roche, Janssen, Takeda; Roche: Consultancy, Other: Advisory Boards: Roche, Janssen, Takeda; Janssen: Consultancy, Other: Advisory Boards: Roche, Janssen, Takeda. Stathis:ADC Therapeutcis: Other, Research Funding; Abbvie: Other: Travel Grant; MEI Pharma: Other, Research Funding; Novartis: Other, Research Funding; Roche: Other, Research Funding; Pfizer: Other, Research Funding; PharmaMar: Other: Travel Grant; Cellestia: Research Funding; Loxo: Honoraria, Other, Research Funding; Member of the steering committee of the trial of this abstract: Other; Bayer: Other, Research Funding; Merck: Other, Research Funding. Gerber:Alnylam: Other: funding for accredited continuing medical education; Axonlab: Other: funding for accredited continuing medical education program ; Bayer: Other: funding for accredited continuing medical education program ; Bristol Myers Squibb: Other: funding for accredited continuing medical education program ; Daiichi-Sankyo: Other: funding for accredited continuing medical education program ; Janssen: Other: funding for accredited continuing medical education program ; Mitsubishi Tanabe Pharma: Other: funding for accredited continuing medical education program ; NovoNordisk: Other: funding for accredited continuing medical education program ; Octapharma: Other; Takeda: Other; Sanofi: Other; SOBI: Other; Thermo Fishe: Other; Axonlab: Other; Pfizer: Other: personal fees ; Sanofi: Other: funding for accredited continuing medical education. Gaidano:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Sunesys: Membership on an entity's Board of Directors or advisory committees. Rossi:Gilead: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding. Zucca:Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grants, Research Funding; Celltrion Healthcare: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Abbvie: Other: Travel Grants; Beigene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Background: In clinical trials, treatment of chronic lymphocytic leukaemia (CLL) with venetoclax (Ven) has shown promising efficacy and good tolerability. However, patients treated in clinical trial often represent a selected group not representative for patients treated in daily practice. Prospective real-world data on Ven usage are limited.