Efficacy and safety of tixagevimab/cilgavimab as passive immunisation against COVID-19 infections in patients with hematological malignancies.

Monoclonal antibodies, as tixagevimab/cilgavimab, have been introduced as prophylaxis against COVID-19 infections in high-risk populations. However, data on efficacy are limited. This study investigates efficacy and tolerability of tixagevimab/cilgavimab in hematological patients under real-life conditions. Tixagevimab/cilgavimab was administered to 155 hematological patients (March-August 2022) at two Austrian centres. S/RBD-antibody assessments were performed before (T0), four weeks (T1), and six months (T2) after application. Side effects, the occurrence of COVID-19 infections, and the course of S/RBD-antibody titres were analysed retrospectively in relation to clinical variables. 155 hematological patients, who refused tixagevimab/cilgavimab, were included as a control group to compare the frequency of COVID-19 infections. Of all immunised patients (52.3% males; 91% triple vaccinated), 25.8% had a COVID-19 breakthrough infection (76% mild) compared to 43.9% in the control group. Patients with chronic lymphocytic leukaemia (CLL)/lymphoma were at highest risk of a COVID-19 infection (OR = 2.21; 95% CI 1.05-4.65; p = 0.037). After immunisation, a steep increase in median antibody levels (1193.4BAU/ml, IQR 0-2318.94) was observed in 67.8%, followed by a rapid decrease between T1 and T2 (465.95BAU/ml, IQR 0-1900.65.3) with the greatest declines in CLL/lymphoma (848.7BAU/ml, IQR 0-1949.6, p = 0.026). Side-effects occurred in 21.2% (CTCAE I/II). These real-world data indicate that S/RBD antibodies respond rapidly after passive immunisation in all hematological patients without safety concerns. Given the rapid decline in S/RBD antibodies, early booster immunisations should be considered for future scenarios in this vulnerable group.

Randomized comparison between KTd and KRd induction therapy followed by maintenance therapy with K or observation in transplant-ineligible patients with newly diagnosed multiple myeloma.

Randomized comparison between KTd and KRd induction followed by second randomization to carfilzomib in transplant-ineligable patients with newly diagnosed multiple myeloma.

Amp(1q) and tetraploidy are commonly acquired chromosomal abnormalities in relapsed multiple myeloma.

Long-term disease control in multiple myeloma (MM) is typically an unmet medical need, and most patients experience multiple relapses. Fluorescence in situ hybridization (FISH) is the standard technique to detect chromosomal abnormalities (CAs), which are important to estimate the prognosis of MM and the allocation of risk adapted therapies. In advanced stages, the importance of CAs needs further investigation. From 148 MM patients, two or more paired samples, at least one of which was collected at relapse, were analyzed by FISH. Using targeted next-generation sequencing, we molecularly investigated samples harboring relapse-associated CAs. Sixty-one percent of the patients showed a change in the cytogenetic profile during the disease course, including 10% who acquired high-risk cytogenetics. Amp(1q) (≥4 copies of 1q21), driven by an additional increase in copy number in patients who already had 3 copies of 1q21, was the most common acquired CA with 16% affected patients. Tetraploidy, found in 10% of the samples collected at the last time-point, was unstable over the course of the disease and was associated with TP53 lesions. Our results indicate that cytogenetic progression is common in relapsed patients. The relatively high frequency of amp(1q) suggests an active role for this CA in disease progression.

Clonal dynamics in a composite chronic lymphocytic leukemia and hairy cell leukemia-variant.

Composite lymphoma is the rare simultaneous manifestation of two distinct lymphomas. Chronic lymphocytic leukemia (CLL) has a propensity for occurring in composite lymphomas, a phenomenon that remains to be elucidated. We applied cytogenetics, droplet digital polymerase chain reaction, and massively parallel sequencing to analyze longitudinally a patient with CLL, who 3 years later showed transformation to a hairy cell leukemia-variant (HCL-V). Outgrowth of the IGHV4-34-positive HCL-V clone at the expense of the initially dominant CLL clone with trisomy 12 and MED12 mutation started before CLL-guided treatment and was accompanied by a TP53 mutation, which was already detectable at diagnosis of CLL. Furthermore, deep sequencing of IGH showed a composite lymphoma with presence of both disease components at all analyzed timepoints (down to a minor clone: major clone ratio of ~1:1000). Overall, our analyses showed a disease course that resembled clonal dynamics reported for malignancies with intratumoral heterogeneity and illustrate the utility of deep sequencing of IGH to detect distinct clonal populations at diagnosis, monitor clonal response to therapy, and possibly improve clinical outcomes.

The prognostic value of additional copies of 1q21 in multiple myeloma depends on the primary genetic event.

Hyperdiploidy (HRD) and specific immunoglobulin heavy locus (IGH) translocations are primary chromosomal abnormalities (CA) in multiple myeloma (MM). In this retrospective study of 794 MM patients we aimed to investigate clinical features and common CA including gain(1q) in separate subgroups defined by primary CA. In the entire group, we confirmed that gain(1q) was associated with short time to next treatment and adverse overall survival (OS). The impact was worse for four or more copies of 1q21 as compared to three copies. However, in a subgroup of patients with clonal gain(11q) and without known primary IGH translocations (CG11q), already three copies of 1q21 were associated with a poor outcome; in the absence of gain(1q), patients in this subgroup had a remarkably long median OS of more than nine years. These cases were associated with HRD, coexpression of CD56 and CD117, male gender, and IgG subtype. In non-CG11q patients, four or more copies of 1q21 (but not three copies) had a significant adverse impact on outcome. Several associations with CA and clinical findings were observed for the defined subgroups. As an example, we found a predominance of early tetraploidy, plasma cell leukemia, and female gender in the t(14;16) subgroup. Our results underscore the importance of subgrouping in MM.

Lessons learned from immunoadsorption for hyperviscosity in IgM multiple myeloma-A case report.

We report the case of a 63-year-old Caucasian woman with multiple relapsed IgM multiple myeloma (MM) and elevated free kappa light chains (fκLC). Due to hyperviscosity syndrome with visual impairment, regular plasma exchanges were performed. As part of her 11th line of therapy, an experimental protocol consisting of pembrolizumab, pomalidomide, and dexamethasone was initiated. To reduce fκLC and immunoglobulin (Ig) M, we performed immunoadsorption (IA) using columns containing recombinant single domain camelid antibody fragments as ligands. We measured pembrolizumab (humanized IgG4 kappa anti-PD1 antibody) levels before and after each IA session and found a 98.1% reduction from baseline with five sessions of IA. Comparable elimination kinetics were observed for serum IgG, whereas fκLC and IgM were eliminated to a substantially lesser extent. These findings highlight that in hyperviscosity syndrome due to IgM MM, broad spectrum IA columns might be only moderately effective compared to total plasma exchange or double filtration plasmapheresis. Monoclonal antibodies are efficiently reduced by extracorporeal therapies and re-dosing is necessary to provide sufficient efficacy. In the case of serious adverse events such as immune-related adverse events, IA might be used to eliminate the monoclonal antibody. Measuring IgG levels might be a reasonable strategy for monitoring drug levels of monoclonal antibodies during IA.

Ixazomib-Thalidomide-Dexamethasone for induction therapy followed by Ixazomib maintenance treatment in patients with relapsed/refractory multiple myeloma.

BACKGROUND: Ixazomib-revlimid-dexamethason showed significant activity in relapsed/refractory multiple myeloma (RRMM). Here, we evaluate ixazomib in combination with thalidomide and dexamethasone for induction treatment followed by ixazomib maintenance therapy in RRMM patients. METHODS: Ninety patients have been included. Ixazomib-thalidomide-dexamethasone (4 mg, day 1, 8, 15; 100 mg daily; and 40 mg weekly) was scheduled for eight cycles followed by maintenance with ixazomib for one year. RESULTS: The overall response rate was 51.1%, 23.3% achieved CR or VGPR and 10% MR resulting in a clinical benefit rate of 61.1%. In patients completing ≥2 cycles, the rates were 60.5%, 27.6% and 68.4%, respectively. Median progression-free survival (PFS) was 8.5 months in all, and 9.4 months in those completing ≥2 cycles. Response rates, PFS and overall survival (OS) were similar in patients with and without t(4;14) and/or del(17p), but PFS and OS was significantly shorter in patients with gain of 1q21. Multivariate regression analysis revealed gain of 1q21 as the most important factor associated with OS. Ixazomib maintenance resulted in an upgrade in the depth of response in 12.4% of patients. Grade 3/4 toxicities were relatively rare. CONCLUSIONS: Ixazomib-thalidomide-dexamethasone followed by ixazomib maintenance therapy is active and well tolerated in patients with RRMM. TRIAL REGISTRATION NUMBER: NCT02410694.

Robo 4 - the double-edged sword in prostate cancer: impact on cancer cell aggressiveness and tumor vasculature.

Background: The magic roundabout receptor 4 (Robo 4) is a tumor endothelial marker expressed in the vascular network of various tumor entities. However, the role of Robo 4 in prostate cancer (PCa), the second common cause of cancer death among men in -developed countries, has not been described yet. Thus, the present study investigates for the first time the impact of Robo 4 in PCa both in the clinical setting and in vitro. Methods and Results: Immunohistochemical analyses of benign and malignant prostate tissue samples of 95 PCa patients, who underwent radical prostatectomy (RPE), revealed a significant elevated expression of Robo 4 as well as its ligand Slit 2 protein in cancerous tissue compared to benign. Moreover, increased Robo 4 expression was associated with higher Gleason score and pT stage. In advanced stage we observed a hypothesis-generating trend that high Robo 4 and Slit 2 expression is associated with delayed development of tumor recurrence compared to patients with low Robo 4 and Slit 2 expression, respectively. In contrast to so far described exclusive expression of Robo 4 in the tumor vascular network, our analyses showed that in PCa Robo 4 is not only expressed in the tumor stroma but also in cancer epithelial cells. This finding was also confirmed in vitro as PC3 PCa cells express Robo 4 on mRNA as well as protein level. Overexpression of Robo 4 in PC3 as well as in Robo 4 negative DU145 and LNCaP PCa cells was associated with a significant decrease in cell-proliferation and cell-viability. Conclusion: In summary we observed that Robo 4 plays a considerable role in PCa development as it is expressed in cancer epithelial cells as well as in the surrounding tumor stroma. Moreover, higher histological tumor grade was associated with increased Robo 4 expression; controversially patients with high Robo 4 tend to exert lower biochemical recurrence possibly reflecting a protective role of Robo 4.

The Aplidin analogs PM01215 and PM02781 inhibit angiogenesis in vitro and in vivo.

BACKGROUND: Novel synthesized analogs of Aplidin, PM01215 and PM02781, were tested for antiangiogenic effects on primary human endothelial cells in vitro and for inhibition of angiogenesis and tumor growth in vivo. METHODS: Antiangiogenic activity of both derivatives was evaluated by real-time cell proliferation, capillary tube formation and vascular endothelial growth factor (VEGF)-induced spheroid sprouting assays. Distribution of endothelial cells in the different phases of the cell cycle was analyzed by flow cytometry. Aplidin analogs were tested in vivo in chicken chorioallantoic membrane (CAM) assays. RESULTS: Both derivatives inhibited angiogenic capacities of human endothelial cells (HUVECs) in vitro at low nanomolar concentrations. Antiangiogenic effects of both analogs were observed in the CAM. In addition, growth of human multiple myeloma xenografts in vivo in CAM was significantly reduced after application of both analogs. On the molecular level, both derivatives induced cell cycle arrest in G1 phase. This growth arrest of endothelial cells correlated with induction of the cell cycle inhibitor p16(INK4A) and increased senescence-associated beta galactosidase activity. In addition, Aplidin analogs induced oxidative stress and decreased production of the vascular maturation factors Vasohibin-1 and Dickkopf-3. CONCLUSIONS: From these findings we conclude that both analogs are promising agents for the development of antiangiogenic drugs acting independent on classical inhibition of VEGF signaling.

New antiangiogenic strategies beyond inhibition of vascular endothelial growth factor with special focus on axon guidance molecules.

Since the approval of the first antiangiogenic agent bevacizumab, a neutralizing antibody against the vascular endothelial growth factor (VEGF), antiangiogenic therapies augmented the standard armamentarium of anticancer therapies and proved their clinical efficacy. Nevertheless, antiangiogenic strategies could not fulfill the expected hopes. In clinical routine, therapy responses to antiangiogenic therapies were mostly transient and most of the patients developed evasive resistance mechanisms during therapy. Further, no predictive biomarker for therapy response could be developed, hampering the clinical development of these agents and triggering skepticism. In the past years, knowledge on the biology of angiogenesis increased and the role of tumor hypoxia was better characterized and identified as the driver for angiogenic regulation mechanisms. Besides VEGF, new angiogenic and antiangiogenic factors were characterized and the process of endothelial cell migration, proliferation and vessel formation was better elucidated. Thus, a strong connection to neural development and axon guidance molecules like netrins, Slit proteins, semaphorins, ephrins and their cognate receptors UNC5, Robo1-4, neuropilin and EphB was identified. The aim of this review is to present the importance of these axon guidance molecules with special focus on Robo4 and semaphorins in tumor angiogenesis and to highlight their value as potential targets for new antiangiogenic therapies.

Polyarteritis nodosa complicating multiple myeloma - a case report and review of the literature.

INTRODUCTION: Polyarteritis nodosa (PAN) is a necrotizing vasculitis of small to-medium-sized vessels, rarely associated with hematologic neoplasms. CASE REPORT: We report a 44-year-old man with a history of monoclonal gammopathy of undetermined significance (MGUS) who presented with rapidly progressing sensorimotor peripheral neuropathy. Two weeks after onset the patient developed severe acute acral and retinal ischemia. MR-angiography and nerve biopsy revealed a systemic necrotizing vasculitis (PAN type). At this time, bone marrow biopsy identified a smoldering multiple myeloma. Immediate immunosuppressive and anti-neoplastic treatment (steroids, immunoglobulins, bortezomib combined with cyclophosphamide followed by lenalidomide maintenance) resulted in a favorable clinical outcome. After 4 years, the patient is in good clinical condition with sustained partial remission from myeloma and without evidence of relapse of PAN. CONCLUSION: This is a remarkable case of a histologically confirmed peripheral neuropathy due to polyarteritis nodosa associated with progression of MGUS to multiple myeloma. Immediate diagnosis and combined immunosuppressive and anti-neoplastic treatment may improve the outcome of this potentially life-threatening clinical condition.

QoL during KTd or KRd induction followed by K maintenance or observation in transplant noneligible patients with newly diagnosed multiple myeloma: Longitudinal and cross-sectional analysis of the randomized AGMT 02 study.

Understanding the impact of induction and maintenance therapy on patients' quality of life (QoL) is important for treatment selection. This study aims to compare patient-reported QoL between patients treated with KTd or KRd induction therapy and K maintenance therapy or observation. QoL was assessed using the EORTC QOL-C 30 and QOL-MY20 questionnaires in the AGMT-02 study, in which 123 patients with newly diagnosed transplant ineligible multiple myeloma were randomized to nine cycles of either KTd or KRd induction therapy, followed by 12 cycles of K maintenance therapy, or observation. Longitudinal assessments showed statistically significant improvements in global health-related QoL, various disease symptoms and pain for both treatment regimens. KTd improved insomnia and fatigue, and KRd improved physical functioning. Cross-sectional comparisons indicated a "slight" superiority of KTd over KRd in several scales, with the exception of higher neuropathy scores with KTd. During maintenance, longitudinal comparisons showed no statistically significant changes. Cross-sectional comparisons revealed a "slight" improvement in cognitive functioning during carfilzomib therapy, but a worsening in most other QoL scales. Induction therapy led to improvements in most QoL items, while maintenance therapy with K maintenance was associated with "slight" or "moderate" impairments in several QoL scales compared with the observation group.

"Idiopathic Bence-Jones proteinuria": a new characterization of an old entity.

Idiopathic Bence-Jones proteinuria (BJP) is a rare plasma cell dyscrasia, of which the clinical and biological characteristics are yet unclear. Historical data suggested that they are at higher risk of progression to multiple myeloma or other related neoplasms, while recent findings are contradictory. To address these open questions, we evaluated a series of both BJP and monoclonal gammopathy of undetermined significance (MGUS) with production of an intact immunoglobulin plus Bence-Jones proteinuria (MGUS+BJP) with long-term follow-up, regarding their clinical characteristics and progression to multiple myeloma, amyloidosis or other related B cell lymphoproliferative disorders. Two hundred and twenty-nine persons fulfilling the 2004 criteria of MGUS were included in the final analyses: 31 had BJP and 198 had MGUS+BJP. At the time of diagnosis, significantly more persons in the BJP group had renal impairment, anaemia and polyneuropathy. A more detailed analysis revealed discrepancies between the serum and urine light chain type in nine cases, reflecting clonal heterogeneity. The number of disease progressions was higher in MGUS+BJP (n = 30) when compared to BJP (n = 1), with a rate of 1.6 and 0.4 progressions per 100 person-years, respectively. In conclusion, BJP has distinct clinical characteristics and a lower risk of progression when compared to MGUS+BJP. Our data suggest that MGUS+BJP being closer to malignant transformation may be due to the higher portion of genetically heterogeneous, pre-malignant plasma cell subclones.

Poor Mobilizers in Lymphoma but Not Myeloma Patients Had Significantly Poorer Progression-Free Survival after Autologous Stem Cell Transplantation: Results of a Large Retrospective, Single-Center Observational Study.

In our single-center study, 357 myeloma and lymphoma patients between 2009 and 2019 were mobilized with granulocyte colony-stimulating factor (G-CSF 7.5 µg/kg bid for four days) plus a fixed dose of 24 mg Plerixafor when indicated (Plerixafor Group, n = 187) or G-CSF alone (G-CSF Group, n = 170). The target CD34 cell yields were ≥2.0 × 106 CD34+ cells/kg in lymphoma and ≥4.0 × 106 CD34+ cells/kg in myeloma patients to enable putative second transplants in the latter. There were no significant differences in engraftment kinetics or transfusion requirements between the Plerixafor Group and the control group in the myeloma cohort, with lymphoma patients not requiring Plerixafor showing significantly faster neutrophil recovery, a trend to faster platelet recovery, and a significantly lower need for platelet transfusions, probably due to the significantly lower number of CD34-positive cells re-transfused. While in myeloma patients the outcome (overall survival, progression-free survival) following autologous stem cell transplantation (ASCT) was similar between the Plerixafor Group and the control group, hard to mobilize lymphoma patients had significantly poorer progression-free survival (47% vs. 74% at 36 months after ASCT, p = 0.003) with a trend also to poorer overall survival (71% vs. 84%). In conclusion, while there seem to be no differences in stemness capacity and long-term engraftment efficiency between the Plerixafor and the G-CSF Group in lymphoma as well as myeloma patients, poor mobilizing lymphoma patients per se constitute a high-risk population with a poorer outcome after ASCT. Whether disease characteristics and/or a more intense or stem cell-toxic pre-mobilization chemo-/radiotherapy burden in this cohort are responsible for this observation remains to be shown in future studies.

Selinexor-Based Triplet Regimens in Patients With Multiple Myeloma Previously Treated With Anti-CD38 Monoclonal Antibodies.

BACKGROUND: The increasing use of anti-CD38 monoclonal antibodies (αCD38 mAbs) for newly diagnosed or early relapsed multiple myeloma (MM), especially in non-transplant eligible patients, may lead to more patients developing αCD38 mAb-refractory disease earlier in the treatment course with fewer treatment options. PATIENTS AND METHODS: We analyzed the efficacy and safety of selinexor-based triplets (selinexor+dexamethasone [Sd] plus pomalidomide [SPd, n = 23], bortezomib [SVd, n = 16] or carfilzomib (SKd, n = 23]) in a subset of STOMP (NCT02343042) and BOSTON (NCT03110562) study patients treated previously with αCD38 mAbs. RESULTS: Sixty-two patients (median 4 prior therapies, range 1 to 11, 90.3% refractory to αCD38 mAb) were included. Overall response rates (ORR) in the SPd, SVd and SKd cohorts were 52.2%, 56.3%, and 65.2%, respectively. Overall response rate was 47.4% among patients who had MM refractory to the third drug reintroduced in the Sd-based triplet. Median progression-free survival in the SPd, SVd, and SKd cohorts was 8.7, 6.7, and 15.0 months, respectively, and median overall survival was 9.6, 16.9, and 33.0 months, respectively. Median time to discontinuation in the SPd, SVd, and SKd cohorts was 4.4, 5.9, and 10.6 months, respectively. The most common hematological adverse events were thrombocytopenia, anemia, and neutropenia. Nausea, fatigue, and diarrhea were primarily grade 1/2. Adverse events were generally manageable with standard supportive care and dose modifications. CONCLUSION: Selinexor-based regimens may offer effective and well-tolerated therapy to patients with relapsed and/or refractory MM who had disease previously exposed or refractory to αCD38 mAb therapy and could help address the unmet clinical need in these high-risk patients.

Autologous and Allogeneic Stem Cell Transplantation as Salvage Treatment Options for Relapsed/Refractory Multiple Myeloma: A Single-center Experience over 20 Years.

BACKGROUND/AIM: Despite multiple treatment options, multiple myeloma (MM) remains an incurable disease with poor outcome. PATIENTS AND METHODS: We retrospectively analyzed the outcome of MM patients undergoing an allogeneic (allo-SCT; n=34) or autologous stem cell transplantation (auto-SCT; n=41) as salvage treatment for relapsed/refractory (r/r) disease. RESULTS: After a median observation period of 79.9 months in the auto group and 15.7 months in the allo group, the 5- and 10-year OS rates were 54% and 44% in the auto group and 17% and 4% in the allo group (p=0.0002), respectively. The 5- and 10-year disease-free survival in the auto group was 21% and 8%, and 14% and 5% in the allo group (p=0.0142), respectively. The 5- and 10-year cumulative incidence of relapse/progression in the auto group was 69% and 82%, and 64% and 69% in the allo group (p=0.0759), respectively. The 5- and 10-year non-relapse mortality in the auto group was significantly lower than that in the allo group [5% versus 45% (p=0.0001)]. CONCLUSION: A second autotransplant in selected r/r patients offers an acceptable long-term outcome partly because of the significantly lower treatment-related morbidity and mortality.

GRP-78 secreted by tumor cells blocks the antiangiogenic activity of bortezomib.

Antiangiogenic effects of the proteasome inhibitor bortezomib were analyzed on tumor xenografts in vivo. Bortezomib strongly inhibited angiogenesis and vascularization in the chicken chorioallantoic membrane. Bortezomib's inhibitory effects on chorioallantoic membrane vascularization were abrogated in the presence of distinct tumor xenografts, thanks to a soluble factor secreted by tumor cells. Through size-exclusion and ion-exchange chromatography as well as mass spectroscopy, we identified GRP-78, a chaperone protein of the unfolded protein response, as being responsible for bortezomib resistance. Indeed, a variety of bortezomib-resistant solid tumor cell lines (PC-3, HRT-18), but not myeloma cell lines (U266, OPM-2), were able to secrete high amounts of GRP-78. Recombinant GRP-78 conferred bortezomib resistance to endothelial cells and OPM-2 myeloma cells. Knockdown of GRP78 gene expression in tumor cells and immunodepletion of GRP-78 protein from tumor cell supernatants restored bortezomib sensitivity. GRP-78 did not bind or complex bortezomib but induced prosurvival signals by phosphorylation of extracellular signal-related kinase and inhibited p53-mediated expression of proapoptotic Bok and Noxa proteins in endothelial cells. From our data, we conclude that distinct solid tumor cells are able to secrete GRP-78 into the tumor microenvironment, thus demonstrating a hitherto unknown mechanism of resistance to bortezomib.

Feasibility and toxicity of concomitant radio/immunotherapy with MabThera (Rituximab®) for patients with non-Hodkin's Lymphoma: results of a prospective phase I/II study.

PURPOSE: Non-Hodgkin's lymphomas (NHL) have a high radio- and chemosensitivity. Although initially responsive, approximately 50% of low grade B-cell lymphomas relapse after 10-15 years. Besides chemo- and radiotherapy, rituximab, a mouse/human chimeric antibody targeting CD20 antigen on the surface of B-cell lymphoma cells, is another treatment approach. In vitro data showed potentiation of radiation-induced apoptosis by addition of rituximab. The purpose of this study was to evaluate the feasibility and toxicity of radiotherapy with concomitant application of rituximab in NHL patients. PATIENTS AND METHODS: A total of 21 patients with B-cell lymphoma (stage I: n = 11; II: n = 5; III: n = 1; IV: n = 4) were included in this study, treated with radiotherapy of 30-40 Gy and weekly application of rituximab (375 mg/m²). Nine patients had R-CHOP chemotherapy previously, 1 patient leuceran chemotherapy, and 2 patients an initial treatment with 6 cycles of rituximab. Mean time of follow-up was 41.7 months. RESULTS: No grade 4 toxicity or treatment-related death was observed. In 1 patient, rituximab application had to be stopped after 3 cycles due to radiation-induced side effects. No late toxicities were reported. All patients were in complete remission after treatment. Progression or relapse was observed in 6 patients (28%); the mean time to progression was 27 months. The mean overall survival (OS) was 53 months. CONCLUSION: Combined radio/immunotherapy is feasible and safe. Treatment was well tolerated, no late toxicities were observed, and treatment outcome is promising. Randomized trials are necessary to clarify the benefit of this treatment approach and its applicability.

Increased levels of NETosis in myeloproliferative neoplasms are not linked to thrombotic events.

Morbidity and mortality of Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are mainly determined by thromboembolic complications. Thrombus formation is facilitated by a neutrophil-specific form of cell death linked to neutrophil extracellular trap (NET) formation (NETosis). Preclinical and clinical data suggested a potential link between NETosis and thrombosis in MPNs. In this study, we aimed to define the impact of NETosis on clinical end points in a large MPN cohort. NETosis was induced in vitro by ionomycin and quantified by enzyme-linked immunosorbent assay-based nucleosome release assays as well as fluorescent staining of free DNA in samples from 103 MPN patients and 28 healthy donors. NETosis rate was correlated with a broad set of clinical data, such as MPN subtype, mutational status, laboratory variables, history of thrombotic events, and treatment types. Triggered NETosis levels were clearly higher in MPN patients than in healthy donors. Positivity for JAK2 V617F or exon 12 as well as CALR mutations correlate with increased NET formation. However, neither JAK2 allelic burden nor history of thromboembolic complication nor the presence of other risk factors for thrombosis (eg, leukocytosis) were associated with the rate of NETosis. In addition, none of the analyzed laboratory parameters nor the type of treatment significantly impacted the rate of NETosis formation. The biology of MPNs has an impact on NET formation because genetic driver mutations favor induction of NETosis, but this does not seems to translate into important clinical end points such as thromboembolic complications. Therefore, NETosis may play a role in facilitating thrombosis, but it is not a sole causative determinant in MPN-associated thrombophilia.