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.

Impact of early cyclosporine A levels on acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation using in vivo T-cell depletion.

BACKGROUND AIMS: Cyclosporin A (CsA) remains a major component of immunosuppressive regimens applied in allogeneic hematopoietic stem cell transplantation (HSCT). The impact of CsA trough levels during the first weeks after HSCT has not yet been investigated specifically in anti-T-lymphocyte globulin (ATLG)-based HSCT from matched related and unrelated donors. METHODS: To address this issue, we have retrospectively examined 307 consecutive matched related (n = 145) and unrelated (n = 162) HSCTs, using peripheral blood stem cells or bone marrow. HSCTs for active, uncontrolled malignancies were excluded. The initial three weeks' average mean CsA trough levels were analyzed in landmark and multi-state models, using a cut-off of 200 ng/mL. RESULTS: CsA levels >200 ng/mL were associated with a reduced risk of acute graft-versus-host disease (GVHD) grade 3-4 at the first-week landmark (subdistribution hazard ratio [SHR] 0.59, P = 0.03) and the second-week landmark (SHR 0.48, P = 0.004), whereas there was no impact at the third-week landmark (HR 0.87, P = 0.69). This was supported by a multi-state model, in which week 1 (hazard ratio [HR] 0.53, P = 0.006) and week 2 (HR 0.48, P = 0.003), but not week 3 (HR 0.80, P = 0.44) CsA levels >200 ng/mL were associated with a reduced acute GVHD 3-4 risk. Relapse incidence was not significantly affected by week 1 through 3 CsA levels. Despite ATLG's inherent GVHD-preventive properties, week 1 CsA trough levels >200 ng/mL following ATLG-based HSCT (n = 220) were associated with a significantly reduced risk of non-relapse mortality (SHR 0.52, P = 0.02) and improved overall survival (HR 0.61, P = 0.02). CONCLUSIONS: Our findings emphasize the continuing importance of ensuring CsA levels ≥200 ng/mL immediately post-transplant in the setting of ATLG-based HSCT.

Allogeneic Stem Cell Transplantation in Multiple Myeloma: Risk Factors and Outcomes in the Era of New Therapeutic Options-A Single-Center Experience.

BACKGROUND: Despite major treatment advances, multiple myeloma remains incurable. The outcome of patients who are refractory to immunomodulatory agents, proteasome inhibitors, and anti-CD38 monoclonal antibodies is poor, and improved treatment strategies for this difficult-to-treat patient population are an unmet medical need. METHODS: This retrospective, unicentric analysis included 38 patients with relapsed/refractory multiple myeloma or plasma cell leukemia who underwent allogeneic stem cell transplantation (allo-HSCT) between 2013 and 2022. Survival outcomes, relapse incidence, and non-relapse mortality were calculated according to remission status, date of allo-HSCT, cytogenetic risk status, timing, and number of previous autologous HSCTs. RESULTS: The median PFS was 13.6 months (95% CI, 7.7-30.4) and the median OS was 51.4 months (95% CI, 23.5-NA) in the overall cohort. The cumulative incidence of relapse at 3 years was 57%, and non-relapse mortality was 16%. The median PFS and OS were significantly longer in patients with very good partial remission (VGPR) or better compared to patients with less than VGPR at the time of allo-HSCT (mPFS 29.7 months (95% CI, 13.7-NA) vs. 6.5 months (95% CI, 2.6-17.0); p = 0.009 and mOS not reached vs. 18.6 months (95% CI, 7.0-NA); p = 0.006). CONCLUSION: For selected patients, allo-HSCT may result in favorable overall survival, in part by providing an appropriate hemato-immunological basis for subsequent therapies.

Successful SARS-CoV-2 mRNA Vaccination Program in Allogeneic Hematopoietic Stem Cell Transplant Recipients-A Retrospective Single-Center Analysis.

(1) Background: mRNA COVID-19 vaccines are effective but show varied efficacy in immunocompromised patients, including allogeneic hematopoietic stem cell transplant (HSCT) recipients. (2) Methods: A retrospective study on 167 HSCT recipients assessed humoral response to two mRNA vaccine doses, using the manufacturer cut-off of ≥7.1 BAU/mL, and examined factors affecting non-response. (3) Results: Twenty-two percent of HSCT recipients failed humoral response. Non-responders received the first vaccine a median of 10.2 (2.5-88.9) months post-HSCT versus 35.3 (3.0-215.0) months for responders (p < 0.001). Higher CD19 (B cell) counts favored vaccination response (adjusted odds ratio (aOR) 3.3 per 100 B-cells/microliters, p < 0.001), while ongoing mycophenolate mofetil (MMF) immunosuppression hindered it (aOR 0.04, p < 0.001). By multivariable analysis, the time from transplant to first vaccine did not remain a significant risk factor. A total of 92% of non-responders received a third mRNA dose, achieving additional 77% seroconversion. Non-converters mostly received a fourth dose, with an additional 50% success. Overall, a cumulative seroconversion rate of 93% was achieved after up to four doses. (4) Conclusion: mRNA vaccines are promising for HSCT recipients as early as 3 months post-HSCT. A majority seroconverted after four doses. MMF usage and low B cell counts are risk factors for non-response.

CAR virus receptor mediates erythroid differentiation and migration and is downregulated in MDS.

Myelodysplastic syndromes (MDS) are myeloid neoplasms presenting with dysplasia in the bone marrow (BM) and peripheral cytopenia. In most patients anemia develops. We screened for genes that are expressed abnormally in erythroid progenitor cells (EP) and contribute to the pathogenesis of MDS. We found that the Coxsackie-Adenovirus receptor (CAR = CXADR) is markedly downregulated in CD45low/CD105+ EP in MDS patients compared to control EP. Correspondingly, the erythroblast cell lines HEL, K562, and KU812 stained negative for CAR. Lentiviral transduction of the full-length CXADR gene into these cells resulted in an increased expression of early erythroid antigens, including CD36, CD71, and glycophorin A. In addition, CXADR-transduction resulted in an increased migration against a serum protein gradient, whereas truncated CXADR variants did not induce expression of erythroid antigens or migration. Furthermore, conditional knock-out of Cxadr in C57BL/6 mice resulted in anemia and erythroid dysplasia. Finally, decreased CAR expression on EP was found to correlate with high-risk MDS and decreased survival. Together, CAR is a functionally relevant marker that is down-regulated on EP in MDS and is of prognostic significance. Decreased CAR expression may contribute to the maturation defect and altered migration of EP and thus their pathologic accumulation in the BM in MDS.

Cox proportional hazards deep neural network identifies peripheral blood complete remission to be at least equivalent to morphologic complete remission in predicting outcomes of patients treated with azacitidine-A prospective cohort study by the AGMT.

The current gold standard of response assessment in patients with myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML) is morphologic complete remission (CR) and CR with incomplete count recovery (CRi), both of which require an invasive BM evaluation. Outside of clinical trials, BM evaluations are only performed in ~50% of patients during follow-up, pinpointing a clinical need for response endpoints that do not necessitate BM assessments. We define and validate a new response type termed "peripheral blood complete remission" (PB-CR) that can be determined from the differential blood count and clinical parameters without necessitating a BM assessment. We compared the predictive value of PB-CR with morphologic CR/CRi in 1441 non-selected, consecutive patients diagnosed with MDS (n = 522; 36.2%), CMML (n = 132; 9.2%), or AML (n = 787; 54.6%), included within the Austrian Myeloid Registry (aMYELOIDr; NCT04438889). Time-to-event analyses were adjusted for 17 covariates remaining in the final Cox proportional hazards (CPH) model. DeepSurv, a CPH neural network model, and permutation-based feature importance were used to validate results. 1441 patients were included. Adjusted median overall survival for patients achieving PB-CR was 22.8 months (95%CI 18.9-26.2) versus 10.4 months (95%CI 9.7-11.2) for those who did not; HR = 0.366 (95%CI 0.303-0.441; p < .0001). Among patients achieving CR, those additionally achieving PB-CR had a median adjusted OS of 32.6 months (95%CI 26.2-49.2) versus 21.7 months (95%CI 16.9-27.7; HR = 0.400 [95%CI 0.190-0.844; p = .0161]) for those who did not. Our deep neural network analysis-based findings from a large, prospective cohort study indicate that BM evaluations solely for the purpose of identifying CR/CRi can be omitted.

Impact of the Recipient's Pre-Treatment Blood Lymphocyte Count on Intended and Unintended Effects of Anti-T-Lymphocyte Globulin in Allogeneic Hematopoietic Stem Cell Transplantation.

Background: In allogeneic hematopoietic stem cell transplantation (HSCT), Anti-T-Lymphocyte Globulin (ATLG) may be used for the prevention of severe graft-versus-host disease (GVHD). ATLG targets both the recipient's lymphocytes and those transferred with the graft. Assuming an inverse relation between the recipient's absolute lymphocyte count (ALC) and exposure of remaining ATLG to the graft, we aim to evaluate the impact of the recipient's ALC before the first ATLG administration on the benefits (prevention of GVHD and GVHD-associated mortality) and potential risks (increased relapse incidence) associated with ATLG. Methods: In recipients of HLA-matched, ATLG-based HSCT (n = 311), we assessed the incidence of acute GVHD, GVHD-related mortality and relapse, as well as other transplant-related outcomes, in relation to the respective ALC (divided into tertiles) before ATLG. Results: The top-tertile ALC group had a significantly increased risk of aGVHD (subhazard ratio (sHR) 1.81; [CI 95%; 1.14-2.88]; p = 0.01) and aGVHD-associated mortality (sHR 1.81; [CI 95%; 1.03-3.19]; p = 0.04). At the highest ATLG dose level (≥45 mg/kg), recipients with lowest-tertile ALC had a trend towards increased relapse incidence (sHR 4.19; [CI 95%; 0.99-17.7]; p = 0.05, n = 32). Conclusions: ATLG dosing based on the recipient's ALC may be required for an optimal balance between GVHD suppression and relapse prevention.

Intensive chemotherapy with or without gemtuzumab ozogamicin in patients with NPM1-mutated acute myeloid leukaemia (AMLSG 09-09): a randomised, open-label, multicentre, phase 3 trial.

BACKGROUND: Acute myeloid leukaemia with mutated NPM1 is associated with high CD33 expression and intermediate-risk cytogenetics. The aim of this study was to evaluate intensive chemotherapy with or without the anti-CD33 antibody-drug conjugate gemtuzumab ozogamicin in participants with newly diagnosed, NPM1-mutated acute myeloid leukaemia. METHODS: This open-label, phase 3 trial was conducted at 56 hospitals in Germany and Austria. Eligible participants were 18 years or older and had newly diagnosed NPM1-mutated acute myeloid leukaemia and an Eastern Cooperative Oncology Group performance status of 0-2. Participants were randomly assigned, using age as a stratification factor (18-60 years vs >60 years), 1:1 to the two treatment groups using allocation concealment; there was no masking of participants and investigators to treatment groups. Participants received two cycles of induction therapy (idarubicin, cytarabine, and etoposide) plus all-trans retinoic acid (ATRA) followed by three consolidation cycles of high-dose cytarabine (or an intermediate dose for those older than 60 years) and ATRA, without or with gemtuzumab ozogamicin (3 mg/m2 administered intravenously on day 1 of induction cycles 1 and 2, and consolidation cycle 1). The primary endpoints were short-term event-free survival and overall survival in the intention-to-treat population (overall survival was added as a co-primary endpoint after amendment four of the protocol on Oct 13, 2013). The secondary endpoints were event-free survival with long-term follow-up, rates of complete remission, complete remission with partial haematological recovery (CRh), and complete remission with incomplete haematological recovery (CRi), cumulative incidences of relapse and death, and number of days in hospital. This trial is registered with ClinicalTrials.gov (NCT00893399) and has been completed. FINDINGS: Between May 12, 2010, and Sept 1, 2017, 600 participants were enrolled, of which 588 (315 women and 273 men) were randomly assigned (296 to the standard group and 292 to the gemtuzumab ozogamicin group). No difference was found in short-term event-free survival (short-term event-free survival at 6-month follow-up, 53% [95% CI 47-59] in the standard group and 58% [53-64] in the gemtuzumab ozogamicin group; hazard ratio [HR] 0·83; 95% CI 0·65-1·04; p=0·10) and overall survival between treatment groups (2-year overall survival, 69% [63-74] in the standard group and 73% [68-78] in the gemtuzumab ozogamicin group; 0·90; 0·70-1·16; p=0·43). There was no difference in complete remission or CRi rates (n=267 [90%] in the standard group vs n=251 [86%] in the gemtuzumab ozogamicin group; odds ratio [OR] 0·67; 95% CI 0·40-1·11; p=0·15) and complete remission or CRh rates (n=214 [72%] vs n=195 [67%]; OR 0·77; 0·54-1·10; p=0·18), whereas the complete remission rate was lower with gemtuzumab ozogamicin (n=172 [58%] vs n=136 [47%]; OR 0·63; 0·45-0·80; p=0·0068). Cumulative incidence of relapse was significantly reduced by gemtuzumab ozogamicin (2-year cumulative incidence of relapse, 37% [95% CI 31-43] in the standard group and 25% [20-30] in the gemtuzumab ozogamicin group; cause-specific HR 0·65; 0·49-0·86; p=0·0028), and there was no difference in the cumulative incidence of death (2-year cumulative incidence of death 6% [4-10] in the standard group and 7% [5-11] in the gemtuzumab ozogamicin group; HR 1·03; 0·59-1·81; p=0·91). There were no differences in the number of days in hospital across all cycles between treatment groups. The most common treatment-related grade 3-4 adverse events were febrile neutropenia (n=135 [47%] in the gemtuzumab ozogamicin group vs n=122 [41%] in the standard group), thrombocytopenia (n=261 [90%] vs n=265 [90%]), pneumonia (n=71 [25%] vs n=64 [22%]), sepsis (n=85 [29%] vs n=73 [25%]). Treatment-related deaths were documented in 25 participants (4%; n=8 [3%] in the standard group and n=17 [6%] in the gemtuzumab ozogamicin group), mostly due to sepsis and infections. INTERPRETATION: The primary endpoints of the trial of event-free survival and overall survival were not met. However, an anti-leukaemic efficacy of gemtuzumab ozogamicin in participants with NPM1-mutated acute myeloid leukaemia is shown by a significantly lower cumulative incidence of relapse rate, suggesting that the addition of gemtuzumab ozogamicin might reduce the need for salvage therapy in these participants. The results from this study provide further evidence that gemtuzumab ozogamicin should be added in the standard of care treatment in adults with NPM1-mutated acute myeloid leukaemia. FUNDING: Pfizer and Amgen.

TOP-PIC: a new tool to optimize pharmacotherapy and reduce polypharmacy in patients with incurable cancer.

PURPOSE: Polypharmacy is a significant problem in patients with incurable cancer and a method to optimize pharmacotherapy in this patient group is lacking. Therefore, a drug optimization tool was developed and tested in a pilot test. METHODS: A multidisciplinary team of health professionals developed a "Tool to Optimize Pharmacotherapy in Patients with Incurable Cancer" (TOP-PIC) for patients with a limited life expectancy. The tool consists of five sequential steps to optimize medications, including medication history, screening for medication appropriateness and drug interactions, a benefit-risk assessment using the TOP-PIC Disease-based list, and shared decision-making with the patient. For pilot testing of the tool, 8 patient cases with polypharmacy were analyzed by 11 oncologists before and after training with the TOP-PIC tool. RESULTS: TOP-PIC was considered helpful by all oncologists during the pilot test. The median additional time required to administer the tool was 2 min per patient (P < 0.001). For 17.4% of all medications, different decisions were made by using TOP-PIC. Among possible treatment decisions (discontinuation, reduction, increase, replacement, or addition of a drug), discontinuation of medications was the most common. Without TOP-PIC, physicians were uncertain in 9.3% of medication changes, compared with only 4.8% after using TOP-PIC (P = 0.001). The TOP-PIC Disease-based list was considered helpful by 94.5% of oncologists. CONCLUSIONS: TOP-PIC provides a detailed, disease-based benefit-risk assessment with recommendations specific for cancer patients with limited life expectancy. Based on the results of the pilot study, the tool seems practicable for day-to-day clinical decision-making and provides evidence-based facts to optimize pharmacotherapy.

Phenotypic characterization of disease-initiating stem cells in JAK2- or CALR-mutated myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are characterized by uncontrolled expansion of myeloid cells, disease-related mutations in certain driver-genes including JAK2, CALR, and MPL, and a substantial risk to progress to secondary acute myeloid leukemia (sAML). Although behaving as stem cell neoplasms, little is known about disease-initiating stem cells in MPN. We established the phenotype of putative CD34+ /CD38- stem cells and CD34+ /CD38+ progenitor cells in MPN. A total of 111 patients with MPN suffering from polycythemia vera, essential thrombocythemia, or primary myelofibrosis (PMF) were examined. In almost all patients tested, CD34+ /CD38- stem cells expressed CD33, CD44, CD47, CD52, CD97, CD99, CD105, CD117, CD123, CD133, CD184, CD243, and CD274 (PD-L1). In patients with PMF, MPN stem cells often expressed CD25 and sometimes also CD26 in an aberrant manner. MPN stem cells did not exhibit substantial amounts of CD90, CD273 (PD-L2), CD279 (PD-1), CD366 (TIM-3), CD371 (CLL-1), or IL-1RAP. The phenotype of CD34+ /CD38- stem cells did not change profoundly during progression to sAML. The disease-initiating capacity of putative MPN stem cells was confirmed in NSGS mice. Whereas CD34+ /CD38- MPN cells engrafted in NSGS mice, no substantial engraftment was produced by CD34+ /CD38+ or CD34- cells. The JAK2-targeting drug fedratinib and the BRD4 degrader dBET6 induced apoptosis and suppressed proliferation in MPN stem cells. Together, MPN stem cells display a unique phenotype, including cytokine receptors, immune checkpoint molecules, and other clinically relevant target antigens. Phenotypic characterization of neoplastic stem cells in MPN and sAML should facilitate their enrichment and the development of stem cell-eradicating (curative) therapies.

Adverse Events in 1406 Patients Receiving 13,780 Cycles of Azacitidine within the Austrian Registry of Hypomethylating Agents-A Prospective Cohort Study of the AGMT Study-Group.

Background: Azacitidine is the treatment backbone for patients with acute myeloid leukemia, myelodysplastic syndromes and chronic myelomonocytic leukemia who are considered unfit for intensive chemotherapy. Detailed reports on adverse events in a real-world setting are lacking. Aims: To analyze the frequency of adverse events in the Austrian Registry of Hypomethylating agents. To compare real-world data with that of published randomized clinical trials. Results: A total of 1406 patients uniformly treated with a total of 13,780 cycles of azacitidine were analyzed. Hematologic adverse events were the most common adverse events (grade 3-4 anemia 43.4%, grade 3-4 thrombopenia 36.8%, grade 3-4 neutropenia 36.1%). Grade 3-4 anemia was significantly more common in the Registry compared to published trials. Febrile neutropenia occurred in 33.4% of patients and was also more common in the Registry than in published reports. Other commonly reported adverse events included fatigue (33.4%), pain (29.2%), pyrexia (23.5%), and injection site reactions (23.2%). Treatment termination due to an adverse event was rare (5.1%). Conclusion: The safety profile of azacitidine in clinical trials is reproducible in a real-world setting. With the use of prophylactic and concomitant medications, adverse events can be mitigated and azacitidine can be safely administered to almost all patients with few treatment discontinuations.

Efficacy and safety of voriconazole as invasive fungal infection prophylaxis in patients with acute myeloid leukemia.

Invasive fungal infections (IFIs) are commonly observed in patients, who are at high risk of severe infections during the neutropenic phase. The aim of this retrospective single-center study was to evaluate the efficacy and safety of voriconazole as a fungal prophylaxis after induction chemotherapy for acute myeloid leukemia (AML) in adult patients. Six proven/probable IFIs were diagnosed in 213 patients with AML (median age 61 years, range 18-85), who received a total of 377 induction chemotherapies. This yielded an incidence rate of 1.6% based on all induction cycles administered. Voriconazole prophylaxis was administered as intended in 317 out of 377 (84%) induction cycles until the end of neutropenia with a median duration of 20 days (range: 2-101 days). In conclusion, voriconazole demonstrates efficacy and safety as a first-line IFI prophylaxis comparable to published data on posaconazole, which is the standard fungal prophylaxis recommendation for AML patients in international guidelines today.

Midostaurin plus intensive chemotherapy for younger and older patients with AML and FLT3 internal tandem duplications.

We conducted a single-arm, phase 2 trial (German-Austrian Acute Myeloid Leukemia Study Group [AMLSG] 16-10) to evaluate midostaurin with intensive chemotherapy followed by allogeneic hematopoietic-cell transplantation (HCT) and a 1-year midosta urin maintenance therapy in adult patients with acute myeloid leukemia (AML) and fms-related tyrosine kinase 3 (FLT3) internal tandem duplication (ITD). Patients 18 to 70 years of age with newly diagnosed FLT3-ITD-positive AML were eligible. Primary and key secondary endpoints were event-free survival (EFS) and overall survival (OS). Results were compared with a historical cohort of 415 patients treated on 5 prior AMLSG trials; statistical analysis was performed using a double-robust adjustment with propensity score weighting and covariate adjustment. Results were also compared with patients (18-59 years) treated on the placebo arm of the Cancer and Leukemia Group B (CALGB) 10603/RATIFY trial. The trial accrued 440 patients (18-60 years, n = 312; 61-70 years, n = 128). In multivariate analysis, EFS was significantly in favor of patients treated within the AMLSG 16-10 trial compared with the AMLSG control (hazard ratio [HR], 0.55; P < .001); both in younger (HR, 0.59; P < .001) and older patients (HR, 0.42; P < .001). Multivariate analysis also showed a significant beneficial effect on OS compared with the AMLSG control (HR, 0.57; P < .001) as well as to the CALGB 10603/RATIFY trial (HR, 0.71; P = .005). The treatment effect of midostaurin remained significant in sensitivity analysis including allogeneic HCT as a time-dependent covariate. Addition of midostaurin to chemotherapy was safe in younger and older patients. In comparison with historical controls, the addition of midostaurin to intensive therapy led to a significant improvement in outcome in younger and older patients with AML and FLT3-ITD. This trial is registered at clinicaltrialsregistry.eu as Eudra-CT number 2011-003168-63 and at clinicaltrials.gov as NCT01477606.

Multistep pathogenesis of chronic myelomonocytic leukemia in patients.

BACKGROUND: A multistep pathogenesis of myeloid leukemia including mutations in epigenetic, spliceosome, and signaling genes has been recently demonstrated in a preclinical model but is poorly validated in patients. METHODS: Clinical, phenotypic, and biologic features were compared between three distinct molecularly defined CMML cohorts including TET2 monomutated patients (T, n = 10), TET2/SRSF2 bimutated patients (TS, n = 19), and patients who had NRAS mutations in addition to TET2/SRSF2 comutations (TSN, n = 14). RESULTS: Median survival was 90, 45, and 9 months, respectively (p = .001). Whereas no patient in the T and TS group transformed into acute myeloid leukemia (AML), 6/14 patients in the TSN group had AML at study entry or transformed during follow-up. Leukocyte counts, blast cell counts, and LDH levels were significantly higher in TSN vs. TS and T, respectively, whereas hemoglobin and platelet values were not significantly different. Increased growth factor-independent myeloid colony formation was restricted to TSN but not found in T and TS, respectively. The proportion of patients showing in vitro myelomonocytic skewing in T, TS, and TSN was 0%, 56%, and 100%, respectively (p = .010). CONCLUSION: Our results demonstrate that the model of multistep pathogenesis in CMML can be recapitulated in patients regarding clinical, phenotypic, and biologic features.

PD-L1 overexpression correlates with JAK2-V617F mutational burden and is associated with 9p uniparental disomy in myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are chronic stem cell disorders characterized by enhanced proliferation of myeloid cells, immune deregulation, and drug resistance. JAK2 somatic mutations drive the disease in 50-60% and CALR mutations in 25-30% of cases. Published data suggest that JAK2-V617F-mutated MPN cells express the resistance-related checkpoint PD-L1. By applying RNA-sequencing on granulocytes of 113 MPN patients, we demonstrate that PD-L1 expression is highest among polycythemia vera patients and that PD-L1 expression correlates with JAK2-V617F mutational burden (R = 0.52; p < .0001). Single nucleotide polymorphism (SNP) arrays showed that chromosome 9p uniparental disomy (UPD) covers both PD-L1 and JAK2 in all MPN patients examined. MPN cells in JAK2-V617F-positive patients expressed higher levels of PD-L1 if 9p UPD was present compared to when it was absent (p < .0001). Moreover, haplotype-based association analyses provided evidence for germline genetic factors at PD-L1 locus contributing to MPN susceptibility independently of the previously described GGCC risk haplotype. We also found that PD-L1 is highly expressed on putative CD34+ CD38- disease-initiating neoplastic stem cells (NSC) in both JAK2 and CALR-mutated MPN. PD-L1 overexpression decreased upon exposure to JAK2 blockers and BRD4-targeting agents, suggesting a role for JAK2-STAT5-signaling and BRD4 in PD-L1 expression. Whether targeting of PD-L1 can overcome NSC resistance in MPN remains to be elucidated in forthcoming studies.

Relapse Protection Following Early Cytomegalovirus Reactivation after Hematopoietic Stem Cell Transplantation Is Limited to HLA-C Killer Cell Immunoglobulin-Like Receptor Ligand Homozygous Recipients.

Although the risk for nonrelapse mortality (NRM) associated with early cytomegalovirus (CMV) reactivation (CMVR) after allogeneic hematopoietic stem cell transplantation (HSCT) is well established, debate is ongoing on whether CMVR may reduce the risk of primary disease relapse. The aim of this study was to evaluate relapse protection following early CMV reactivation after HSCT in the context of the recipient HLA-C killer cell immunoglobulin-like receptor ligands (KIRLs). In this retrospective bicentric study, 406 matched related or unrelated donor transplantations for acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) were stratified by HLA-C KIRL group (homozygous versus heterozygous) and analyzed separately for the impact of early CMVR on the cumulative incidences of relapse, NRM, and acute and chronic graft-versus-host-disease (GVHD) using landmark and multistate analyses. By landmark analysis of patients alive and relapse-free at 45 days post-HSCT, HLA-C KIRL homozygous recipients (C1/1 or C2/2) had a lower risk of subsequent relapse if CMVR occurred before this landmark (subhazard ratio [sHR], 0.36; P = .002). In contrast, in HLA-C KIRL heterozygous (C1/2) recipients, early CMVR had no impact on subsequent relapse (sHR, 0.88; P = .63). NRM (sHR, 3.31; P < .001) and grade III-IV acute GVHD (sHR, 2.60; P = .04) were significantly increased after early CMVR in the homozygous cohort, but not in the heterozygous cohort (NRM: sHR, 1.23; P = .53; grade III-IV acute GVHD: sHR, 1.40; P = .50). Multivariable landmark analyses and a multistate model confirmed the limitation of the relapse-protective effect of early CMVR to the homozygous cohort. Chronic GVHD and overall survival were not influenced in neither cohort. An antileukemic effect of early CMVR after HSCT for AML/MDS was significant but strictly limited to recipients homozygous for HLA-C KIRL. However, particularly in this cohort, CMVR had an adverse impact on aGVHD and NRM.

Impact of age on the cumulative risk of transformation in patients with chronic myelomonocytic leukaemia.

In older patients with chronic myelomonocytic leukaemia (CMML) and limited life expectancy due to age and or comorbidities, it is particularly important to consider the risk of transformation for individualised treatment decisions. There is limited information on potential differences between younger and older CMML patients regarding the cumulative risk of transformation as well as haematological, molecular and biologic characteristics. We analysed data from the Austrian Biodatabase for CMML (ABCMML) to compare these parameters in 518 CMML patients. Categorisation of patients into 3 age-related groups: <60 years, 60-79 years and ≥80 years, showed a significantly lower risk of transformation at higher age by competing risk analysis, with a 4-year risk of 39%, 23% and 13%, respectively (P < .0001). The lower probability of transformation was associated with a lower percentage of blast cells in the peripheral blood (PB) of older patients. Furthermore, we provide a simple score based on age, PB blasts and platelet counts that allowed us to define subgroups of CMML patients with a different cumulative transformation risk, including a low-risk group with a transformation risk of only 5%. Our findings may facilitate reasonable treatment decisions in elderly patients with CMML.

Molecular Basis and Clinical Application of Growth-Factor-Independent In Vitro Myeloid Colony Formation in Chronic Myelomonocytic Leukemia.

We have originally reported that colony-forming units granulocyte/macrophage (CFU-GM) formation is an in vitro feature of chronic myelomonocytic leukemia (CMML) and a strong predictor for short survival. Elucidation of the molecular basis underlying this in vitro phenomenon could be helpful to define molecular features that predict inferior outcome in patients. We studied the correlation between the mutational landscape and spontaneous colony formation in 164 samples from 125 CMML patients. As compared to wildtype samples, spontaneous in vitro CFU-GM formation was significantly increased in samples containing mutations in NRAS, CBL and EZH2 that were confirmed as independent stimulatory factors by multiple regression analysis. Inducible expression of mutated RAS but not JAK2 was able to induce growth factor independence of Ba/F3 cells. Whereas high colony CFU-GM growth was a strong unfavorable parameter for survival (p < 0.00001) and time to transformation (p = 0.01390), no single mutated gene had the power to significantly predict for both outcome parameters. A composite molecular parameter including NRAS/CBL/EZH2, however, was predictive for inferior survival (p = 0.00059) as well as for increased risk of transformation (p = 0.01429). In conclusion, we show that the composite molecular profile NRAS/CBL/EZH2 derived from its impact on spontaneous in vitro myeloid colony formation improves the predictive power over single molecular parameters in patients with CMML.

Clinical, Hematologic, Biologic and Molecular Characteristics of Patients with Myeloproliferative Neoplasms and a Chronic Myelomonocytic Leukemia-Like Phenotype.

Patients with a myeloproliferative neoplasm (MPN) sometimes show a chronic myelomonocytic leukemia (CMML)-like phenotype but, according to the 2016 WHO classification, a documented history of an MPN excludes the diagnosis of CMML. Forty-one patients with an MPN (35 polycythemia vera (PV), 5 primary myelofibrosis, 1 essential thrombocythemia) and a CMML-like phenotype (MPN/CMML) were comprehensively characterized regarding clinical, hematologic, biologic and molecular features. The white blood cell counts in MPN/CMML patients were not different from CMML patients and PV patients. The hemoglobin values and platelet counts of these patients were higher than in CMML but lower than in PV, respectively. MPN/CMML patients showed myelomonocytic skewing, a typical in vitro feature of CMML but not of PV. The mutational landscape of MPN/CMML was not different from JAK2-mutated CMML. In two MPN/CMML patients, development of a CMML-like phenotype was associated with a decrease in the JAK2 V617F allelic burden. Finally, the prognosis of MPN/CMML (median overall survival (OS) 27 months) was more similar to CMML (JAK2-mutated, 28 months; JAK2-nonmutated 29 months) than to PV (186 months). In conclusion, we show that patients with MPN and a CMML-like phenotype share more characteristics with CMML than with PV, which may be relevant for their classification and clinical management.