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Chronic myelomonocytic leukemia (CMML) is an aggressive disease in which survival after allogeneic hematopoietic stem cell transplantation (HCT) remains relatively poor. An assessment of prognostic factors is an important part of treatment decision making and has the potential to be greatly improved by the inclusion of molecular genetics. However, there is a significant knowledge gap in the interpretation of mutational patterns. This study aimed to describe outcomes of allogeneic HCT in patients with CMML in relation to clinical and molecular genetic risk factors. This retrospective study included 64 patients with CMML who underwent allogeneic HCT between 2008 and 2018, with a median follow-up of 5.4 years. Next-generation sequencing using targeted myeloid panels was carried out on saved material from 51 patients from the time of transplantation. Kaplan-Meier and Cox regression were used for analysis of overall survival (OS), and cumulative incidence with competing risks and Fine and Gray models were used for analysis of relapse and nonrelapse mortality (NRM). Mutations were detected in 48 patients (94%), indicating high levels of minimal residual disease (MRD) positivity at transplantation, even among those in complete remission (CR) (n = 14), 86% of whom had detectable mutations. The most frequently mutated genes were ASXL1 (37%), TET2 (37%), RUNX1 (33%), SRSF2 (26%), and NRAS (20%). Risk stratification using the CMML-specific Prognostic Scoring System molecular score (CPSS-Mol) resulted in 45% of patients moving to a higher risk-group compared with risk stratification using the CPSS. High leucocyte count (≥13 × 109/L), transfusion requirement, and previous intensive chemotherapy were associated with higher incidence of relapse. Being in CR was not linked to better outcomes. Neither ASXL1 nor RUNX1 mutation was associated with a difference in OS, relapse, or NRM, despite being high risk in the nontransplantation setting. TET2 mutations were associated with a significantly higher 3-year OS (73% versus 40%; P = .039). Achieving MRD-negative CR was rare in this CMML cohort, which may explain why we did not observe better outcomes for those in CR. This merits further investigation. Our analyses suggest that the negative impact of ASXL1 and RUNX1 mutations can be overcome by allogeneic HCT; however, risk stratification is complex in CMML and requires larger cohorts and multivariate models, presenting an ongoing challenge in this rare disease.

Introduction One third of patients with myelodysplastic syndrome (MDS) will relapse after allogeneic stem cell transplantation (SCT), with a dismal prognosis. Early detection of relapse enables pre-emptive treatment and may potentially reduce relapse risk, but is limited by the lack of sensitive markers for minimal residual disease (MRD). We developed a pipeline where patient-specific mutations, as determined by a myeloid next generation sequencing (NGS) panel are tracked using sensitive digital droplet PCR (ddPCR). Method We designed a prospective Nordic study (NMDSG14B; NCT02872662) enrolling all patients with MDS, mixed MDS / MPN or AML with myelodysplasia related disease and < 30% marrow blasts undergoing SCT in the Nordic region. We hypothesized that personalized MRD detection by ddPCR can predict clinical relapse earlier than conventional methods. Patients were included before SCT and serial bone marrow samples were collected before, and 1 and 3 months post SCT, and thereafter every third month for 2 years or until relapse or death. Blood samples were collected monthly. The MRD results were not available for the treating physicians. MRD positivity was defined based on the background noise of the specific ddPCR-assays and varied between 0.05-0.1% VAF. Results Three-hundred and sixteen patients were screened between 2016 and 2020, of which 19 were excluded due to lack of mutation or disease progression preventing SCT. We here present data of 254 patients followed ≥ 6 months after SCT. Median age was 64 (18-78) years and 59% were male. Most WHO subgroups of MDS (n=166), MDS/MPN (n=39), AML (n=8) and therapy-related disease (n=41), were represented. Risk profile according to IPSS-R was very low (n=13), low (n=32), intermediate (n=46), high (n=60) and very high (n=32). The majority of patients received pre-SCT treatment consisting of HMA (n=159) and / or intensive chemotherapy (n=59) while 60 patients did not receive disease-modifying treatment prior to SCT. The most common mutations were ASXL1 (n=69), TET2 (n=58), SRSF2 (n=57) and TP53 (n=44). No mutation was identified in 10 pts, and NGS data is still pending for 11 patients. After a median follow-up of 436 days, estimated 2 years overall survival and relapse free survival were 72% and 63%, respectively. Cumulative incidence of NRM and relapse at 2 years was 16% and 20%, respectively. Forty-six patients relapsed after a median of 170 (53-733) days, and the estimated median survival following relapse was 197 days. The most common pre-SCT mutations in the relapsed cohort were TP53 (n=19), DNMT3A (n=11) and RUNX1 (n=9). Thirty-seven patients died due to non-relapse mortality (NRM) after a median of 83 (4-754) days. To date, MRD results are available for 64 patients. Relapse was preceded by positive MRD in 14 out of 15 patients a median of 79 (21-173) days before clinical relapse. The 15th patient had an extra-medullary relapse only. Borderline positive MRD samples < 0.2% VAF within 100 days after SCT followed by negative samples were seen in 11 non-relapse patients. Twenty-four of 37 patients in continuous complete remission (CCR) were consistently MRD neg. Six CCR patients had positive MRD after 100 days; two with transient borderline peaks ( 0.1%, which turned negative when the patients developed GVHD; one patient with slowly decreasing MRD which turned negative first after 1 y, and finally one patient with prevailing KIT mutation (>700 days post-SCT) despite negative BCOR and STAG2. Two MRD+ patients died from NRM without showing signs of clinical relapse. Discussion In summary, we show that our pipeline of personalized MRD-assessment, based on patient-specific mutations is feasible with a high sensitivity to predict relapse. An update of study progression will be presented at the meeting. Figure 1 Disclosures Illman: Sanofi-Genzyme: Other: Travel Support; Celgene: Other: Travel Support. Mielke:DNA Prime: Honoraria, Other: received via my institution , Speakers Bureau; KIADIS Pharma: Honoraria, Other: received via my institution , Speakers Bureau; Miltenyi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: received via my institution , Speakers Bureau; Kite/Gilead: Honoraria, Other: received via my institution , Speakers Bureau; Bellicum: Honoraria, Other: received via my institution, Speakers Bureau; Novartis: Honoraria, Other: received via my institution, Speakers Bureau; Celgene/BMS: Honoraria, Other: received via my institution , Speakers Bureau. Ebeling:Accord Healthcare: Other: Travel Support; Amgen: Other: Travel Support; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support; Otsuka Pharma Scandanavia AB: Consultancy, Membership on an entity's Board of Directors or advisory committees.

// Olle Werlenius 1,2 , Johan Aurelius 1,2 , Alexander Hallner 2 , Ali A. Akhiani 2 , Maria Simpanen 2 , Anna Martner 2 , Per-Ola Andersson 3 , Kristoffer Hellstrand 2 and Fredrik B. Thoren 2 1 Department of Hematology, Sahlgrenska University Hospital, Gothenburg, Sweden 2 TIMM Laboratory, Sahlgrenska Cancer Center, University of Gothenburg, Gothenburg, Sweden 3 Department of Medicine, Sodra Alvsborgs Hospital, Boras, Sweden Correspondence to: Fredrik B. Thoren, email: // Keywords : monoclonal antibodies, reactive oxygen species, immunotherapy, NK cells, NOX2 Received : March 31, 2016 Accepted : April 03, 2016 Published : April 16, 2016 Abstract The antibody-dependent cellular cytotoxicity (ADCC) of natural killer (NK) cells is assumed to contribute to the clinical efficacy of monoclonal antibodies (mAbs) in chronic lymphocytic leukemia (CLL) and other hematopoietic malignancies of B cell origin. We sought to determine whether reactive oxygen species (ROS)-producing monocytes regulate the ADCC of NK cells against primary CLL cells using anti-CD20 as the linking antibody. The monoclonal CD20 antibodies rituximab and ofatumumab were found to trigger substantial release of ROS from monocytes. Antibody-exposed monocytes induced NK cell apoptosis and restricted NK cell-mediated ADCC against autologous CLL cells. The presence of inhibitors of ROS formation and scavengers of ROS preserved NK cell viability and restored NK cell-mediated ADCC against primary CLL cells. We propose that limiting the antibody-induced induction of immunosuppressive ROS may improve the anti-leukemic efficacy of anti-CD20 therapy in CLL.

Antigen-loaded dendritic cells (DCs) used as anticancer vaccine holds promise for therapy, but needs to be optimized. The most frequently described DC vaccine is being matured with a cocktail containing prostaglandin E2 (PGE2 DC). However, even though PGE2 DCs express both costimulatory and migratory receptors, their IL-12p70-prodcution is low, leading to an insufficient Th1 immune response. As an alternative, α-type-1 polarized DCs (αDC1s) have shown a superior production of IL-12p70 and subsequent activation of effector cells. From chronic lymphocytic leukaemia (CLL) patients, αDC1s can be generated to induce a functional Th1-immune response. Yet, another costimulatory receptor, CD70, appears to be essential for optimal DC function by promotion of T cell survival and function. So far, PGE2 is suggested as one of the most important factors for the induction of CD70 expression on DCs. Therefore, we wanted to investigate whether αDC1s have the ability to express functional CD70. We found that CD70 expression on αDC1s could be upregulated in the same manner as PGE2 DCs. In an allogeneic mixed leucocyte reaction, we found that antibody-blocking of CD70 on αDC1s from controls reduced effector cell proliferation although this could not be found when using CLL αDC1s. Nevertheless, CD70-blocking of αDC1s from both controls and patients with CLL had a negative influence on the production of both IL-12p70 and the Th1 cytokine IFN-γ, while the production of the Th2 cytokine IL-5 was enhanced. Together, this study further suggests that αDC1s should be considered as a suitable candidate for clinical antitumour vaccine strategies in patients with CLL.

The prognosis of diffuse large B-cell lymphoma (DLBCL) has improved significantly since the introduction of immunochemotherapy (rituximab [R] with cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP]). However, few outcome data are available for very elderly patients (≥ 80 years). Therefore, we compared all patients with DLBCL aged ≥ 80 years diagnosed in the Gothenburg area during two time periods (2006-2009, "post-R" and 1997-2000, "pre-R"). Forty and 30 patients were identified, corresponding to 23.5% and 20.5%, respectively, of the entire population with DLBCL. Estimated 3-year progression-free (PFS) and overall (OS) survival was better post-R than pre-R: 41% vs. 17% (p = 0.015) and 41% vs. 17% (p = 0.01), respectively. Fifty-three percent of post-R patients were treated with curative intent with a moderately reduced R-CHOP regimen (median relative dose intensity: 0.86). At a median follow-up of 29 months, the 3-year PFS and OS were 70% (p = 0.018) and 76% (p = 0.0089), respectively. In conclusion, moderately reduced R-CHOP is tolerable and effective for a considerable number of very elderly patients with DLBCL and high age by itself should not be a reason for excluding a patient with DLBCL from such treatment.

The Rai and Binet staging systems are currently being challenged by the development of new biological methods to characterize the prognosis and management of chronic lymphocytic leukemia (CLL). To evaluate these two systems in recently diagnosed CLL patients, we performed a retrospective population-based study including 344 patients in western Sweden diagnosed between 1995 and 2000. Binet stage A patients had longer median overall survival (OS) (100 months) than stage B (55 months; P < 0.001) and C patients (45 months; P < 0.0005). Median OS for stage B and C could not be separated (P = 0.94). When transferring Rai stages into three groups, a similar pattern was found. Overall response differed only between Binet A and C patients and there was no difference regarding time to next treatment between any of the Binet stages. Finally, in both systems, low stage patients had inferior survival compared to age- and sex-matched controls. Our data emphasize the need for a new risk stratification system for CLL pat...

To the editor: In a recent study, Golay and coworkers address the commonly overlooked role of neutrophils in therapy of chronic lymphocytic leukemia (CLL) with monoclonal antibodies (mAbs).[1][1] Convincingly, they demonstrate that both rituximab (RTX) and, to a greater extent, glycoengineered