Thromboembolic events in patients with paroxysmal nocturnal hemoglobinuria (PNH): Real world data of a Greek nationwide multicenter retrospective study

Thrombosis is the most common and a life-threatening complication in patients with Paroxysmal Nocturnal Hemoglobinuria. One-third of patients with PNH experience at least one thromboembolic event during the course of the disease, with thrombosis being the most common cause of death in these patients. The mechanism of thrombosis in PNH is complex and continues to be of great research interest. Since the introduction of C5 complement inhibitors in the treatment of PNH, the incidence of thromboembolic events has decreased substantially. We retrospectively analyzed data concerning the thrombotic episodes of 41 patients with PNH from 14 different national hematology centers in Greece. Sixteen patients (39%) experienced at least one episode of thrombosis, including, seven (43.8%) at diagnosis, seven (43.8%) during the course of the disease and two (12.5%) patients prior to PNH diagnosis. Nearly half of these individuals (n=7, 43.8%) had multiple episodes of thrombosis during the course of their disease. The most common sites of thrombosis were intra-abdominal veins. Three out of 26 patients developed thrombosis while on eculizumab. In none of the 16 patients, the thrombotic event was fatal. Our findings, despite the small number of patients, confirmed that thrombosis continues to be a significant complication of PNH affecting more than one third of the patients.

Aplastic anemia and paroxysmal nocturnal hemoglobinuria in children and adults in two centers of Northern Greece

Bone marrow failure (BMF) syndromes are a group of various hematological diseases with cytopenia as a main common characteristic. Given their rarity and continuous progress in the field, we aim to provide data considering the efficiency and safety of the therapeutic methods, focusing on the treatment of aplastic anemia(AA) and paroxysmal nocturnal hemoglobinuria (PNH). We enrolled consecutive patients diagnosed with BMF in two referral centers of Northern Greece from 2008 to 2020. We studied 43 patients with AA (37 adults and 6 children/adolescents) and 6 with classical PNH. Regarding classical PNH, 4 patients have received eculizumab treatment with 1/4 presenting extravascular hemolysis. Among 43 patients with aplastic anemia, PNH clones were detected in 11. Regarding patients that did not receive alloHCT (n=15), 14/15 were treated with ATG and cyclosporine as first line, with the addition of eltrombopag in patients treated after its approval (n=9). With a median follow-up of 16.7 (1.8-56.2) months from diagnosis, 12/14 (85.7%) are alive (4-year OS: 85.1%). AlloHCT was performed in 28 patients. Five patients developed TA-TMA which did not resolve in 3/5 (all with a pre-transplant PNH clone). With the follow-up among survivors reaching 86.3 (6.3-262.4) months, 10-year OS was 56.9%, independently associated with PNH clones after adjusting for age (p=0.024). In conclusion, our real-world experience confirms that novel treatments are changing the field of BMF syndromes. Nevertheless, there is still an unmet need to personalize algorithms in this field.

The Role of Myeloid-Derived Suppressor Cells (MDSCs) in Graft-versus-Host Disease (GVHD)

Background: Myeloid-derived suppressor cells (MDSCs) are implicated in the complex interplay involving graft-versus-leukemia (GVL) effects and graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HCT) in hematologic malignancies. Methods: A review of literature through PubMed was undertaken to summarize the published evidence on the pathophysiology and clinical implications of MDSCs in allo-HCT. Literature sources published in English since 1978 were searched, using the terms Natural Suppressor (NS) cells, MDSCs, GVHD, and allo-HCT. Results: In vivo studies demonstrated that MDSCs derived from mobilization protocols could strongly suppress allo-responses mediated by T cells and enhance T-Reg activity, thus inhibiting GVHD toxicity. However, the influence of MDSCs on the GVL effect is not fully defined. Conclusions: The induction or maintenance of MDSC suppressive function would be advantageous in suppressing inflammation associated with GVHD. Pathways involved in MDSC metabolism and the inflammasome signaling are a promising field of study to elucidate the function of MDSCs in the pathogenesis of GVHD and translate these findings to a clinical setting.

Carfilzomib Improves Bone Metabolism in Patients with Advanced Relapsed/Refractory Multiple Myeloma: Results of the CarMMa Study

Simple Summary

Carfilzomib with dexamethasone is an important therapeutic option for patients with relapsed/refractory multiple myeloma. We sought to evaluate the effect of this regimen on the bone-related outcomes, which are associated with both quality of life and survival. Among 25 patients, less than one third experienced a new skeletal-related event during treatment, even in the absence of any bone-targeted agent. Interestingly, there was a significant decrease in serum biomarkers of bone resorption, which was at least partially due to the sRANKL/OPG ratio reduction. Furthermore, Kd produced an increase in markers of bone formation. Importantly, these changes were independent of myeloma response to treatment. Therefore, the combination of carfilzomib and dexamethasone improves bone metabolism and bone health in patients with advanced multiple myeloma.

Abstract

Carfilzomib with dexamethasone (Kd) is a well-established regimen for the treatment of relapsed/refractory multiple myeloma (RRMM). There is limited information for the effects of Kd on myeloma-related bone disease. This non-interventional study aimed to assess skeletal-related events (SREs) and bone metabolism in patients with RRMM receiving Kd, in the absence of any bone-targeted agent. Twenty-five patients were enrolled with a median of three prior lines of therapy; 72% of them had evidence of osteolytic bone disease at study entry. During Kd treatment, the rate of new SREs was 28%. Kd produced a clinically relevant (≥30%) decrease in C-telopeptide of collagen type-1 (p = 0.048) and of tartrate-resistant acid phosphatase-5b (p = 0.002) at 2 months. This reduction was at least partially due to the reduction in the osteoclast regulator RANKL/osteoprotegerin ratio, at 2 months (p = 0.026). Regarding bone formation, there was a clinically relevant increase in osteocalcin at 6 months (p = 0.03) and in procollagen type I N-propeptide at 8 months post-Kd initiation. Importantly, these bone metabolism changes were independent of myeloma response to treatment. In conclusion, Kd resulted in a low rate of SREs among RRMM patients, along with an early, sustained and clinically relevant decrease in bone resorption, which was accompanied by an increase in bone formation, independently of myeloma response and in the absence of any bone-targeted agent use.

Paroxysmal nocturnal hemoglobinuria and myelodysplastic syndrome: Disappearance of cytogenetic abnormalities

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare life-threatening disease resulting from clonal hematopoietic stem cell evolution. There is a strong link between PNH and other acquired bone marrow failure syndromes, including myelodysplastic syndrome (MDS). Cytogenetic, morphological abnormalities or both are observed in the range of MDS/PNH diagnosis. Herein, we investigate cytogenetic abnormalities in PNH patients. We found two patients with PNH clones and MDS-associated abnormalities that later disappeared. The first patient, originally diagnosed with MDS and Trisomy 6, developed a large PNH clone. At the time of PNH diagnosis, the abnormal cytogenetic clone was no longer detectable despite persistent trilineage dysplasia. In the second patient, a large PNH clone and MDS-defining abnormality were detected at diagnosis, without evidence of dysplasia. No cytogenetic abnormalities were evident after complement inhibition. Our report adds significant information on the complex link between MDS and PNH, suggesting that distinction between these entities may be difficult in some cases. Especially in transplant eligible patients, the clinical phenotype may be the leading feature for treatment decisions in the era of complement inhibition. Lastly, the transient presence of cytogenetic abnormalities is a unique characteristic of our patients' course that needs to be further elucidated in larger studies.

Real-world data on Len/Dex combination at second-line therapy of multiple myeloma: treatment at biochemical relapse is a significant prognostic factor for progression-free survival

We evaluated progression-free survival (PFS) rate of patients treated with lenalidomide/dexamethasone (Len/Dex), the efficacy of the combination, and the prognostic significance of treatment at biochemical vs. clinical relapse on PFS in 207 consecutive myeloma patients treated with Len/Dex in second line, according to routine clinical practice in Greece. First-line treatment included bortezomib-based (63.3%) or immunomodulatory drug-based (34.8%) therapies; 25% of patients underwent autologous stem cell transplantation. Overall response rate was 73.4% (17.8% complete response and 23.7% very good partial response); median time to best response was 6.7 months. Overall, median PFS and 12-month PFS rate was 19.2 months and 67.6%, respectively. 67.5% of patients had biochemical relapse and 32.5% had clinical relapse prior to initiation of Len/Dex. Median PFS was 24 months for patients treated at biochemical relapse vs. 13.2 months for those treated at clinical relapse (HR:0.63, p = 0.006) and the difference remained significant after adjustment for other prognostic factors. Type of relapse was the strongest prognostic factor for PFS in multivariate analysis. These real-world data confirm the efficacy of Len/Dex combination at first relapse; more importantly, it is demonstrated for the first time outside a clinical trial setting that starting therapy with Len/Dex at biochemical, rather than at clinical relapse, is a significant prognostic factor for PFS, inducing a 37% reduction of the probability of disease progression or death.

Extramedullary relapse and discordant CD19 expression between bone marrow and extramedullary sites in relapsed acute lymphoblastic leukemia after blinatumomab treatment

Blinatumomab, a bispecific T-cell engager antibody construct targeting CD19, has been shown to improve the outcome in patients with relapsed and/or refractory B-cell acute lymphoblastic leukemia. Treatment with blinatumomab demonstrated significant survival benefit over chemotherapy, supporting its use as a bridge therapy to allogeneic hematopoietic stem cell transplantation. Unfortunately, following initial response, approximately 50% of responding patients eventually relapse. At the time of failure, the majority of patients have CD19-positive blasts, yet a concerning number of CD19-negative relapses has been reported. In the data reported herein, we present an interesting case of a 42-year-old patient with primary refractory B-cell acute lymphoblastic leukemia who achieved complete morphologic remission after one cycle of blinatumomab as a single agent. Notably, and in the absence of extramedullary disease history, the response in marrow coincided with the emergence of CD19-positive extramedullary relapse including sites of previous punctures for blood and bone marrow samples, as confirmed by biopsy, as well as parenchymal organs (eg breast and lung). During the second cycle of blinatumomab, a CD19-negative morphological relapse emerged. The loss of CD19 was a transient event, as leukemic cells partially regained it after chemotherapy. This study illustrates a challenging situation of relapsed and refractory acute lymphoblastic leukemia complicated with extramedullary disease after exposure to a bispecific T-cell engager antibody, such as blinatumomab. Physicians should maintain a high level of suspicion for the evolution of extramedullary leukemia. This pattern of resistance and/or relapse to blinatumomab resembles the graft-versus-leukemia effect after allogeneic transplantation (stronger in blood and marrow than in other tissues). Mechanisms of resistance to blinatumomab are not yet clear. Combination treatments for refractory patients and those at high risk for exramedullary disease may warrant future assessment.

A matched pair analysis of conditioning BuEM versus BEAM in autologous haematopoietic cell transplantation for lymphomas in terms of toxicity and efficacy

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Background: In autologous hematopoietic cell transplantation (AHCT) for lymphomas, the optimal conditioning regimen is currently investigated. The standard conditioning used is BEAM. During 2009-2011 a new alternative Busulphan-based conditioning regimen constructed in our unit, consisting of Busilvex (9.6 mg/Kg), Etoposide (9.6 mg/Kg) and Melphalan (140mg/m^2) (BuEM) was used. We retrospectively analysed the outcome of patients (pts) conditioned with BEAM and BuEM regimen, in terms of toxicity and efficacy, in a matched pair analysis. Methods: A matched paired analysis on a 1:2 ratio was performed. Thus, 2 control cases (receiving BEAM regimen) were matched to each patient treated with BuEM according to: phase of transplant, age, lines of previous chemotherapy. The first 50 consecutive pts treated with BuEM were matched to a random sample from the historical BEAM control population. Ninety-three BEAM pts that fulfilled the matching criteria were eventually randomly selected. Concerning pts characteristics there were no statistical significant differences except from more chemoresistant disease in the BuEM cohort (p=0.008). Thus a second matched pair analysis was conducted upon stratification by disease chemosensitivity instead of age as a risk factor. Results: Progression free survival and overall survival (OS) were 70.6% and 81.8% for the BEAM vs 68.9% and 83% for the BuEM cohort respectively (p=ns). In the BuEM cohort a borderline significantly better OS was noted in Hodgkin’s pts receiving BuEM (p=0.05). In terms of early toxicity a significantly faster neutrophil engraftment was found in the BEAM cohort, but there was a significantly less need of red blood cells, platelet transfusions and GCSF infusion in the BuEM cohort. BEAM regimen was also associated with: reduced incidence of infections (p=0.02), less severe (grade 3-4) mucositis (p=0.000) and liver toxicity (p=0.004). Conclusions: BEAM regimen was correlated with a favourable reduced early toxicity profile, ie severe mucositis and liver impairment. On the other hand, BuEM was found to be equally efficacious and moreover offered improved overall survival in Hodgkin’s lymphoma pts.

Splenic Marginal-zone Lymphoma: One or More Entities? A Histologic, Immunohistochemical, and Molecular Study of 42 Cases

We analyzed 42 splenic marginal-zone lymphoma (SMZL) cases diagnosed on splenectomy specimens after established World Health Organization criteria. A predominantly nodular growth pattern was observed in 24 cases; the remainder showed predominantly (11/42) or exclusively (7/42) diffuse infiltration. Twenty-one cases showed the "classic" biphasic appearance; 13 cases exhibited marginal-zone morphology; finally, 8 cases were composed predominantly of small cells. CD21 and CD35 were expressed by 12/42 and 17/38 cases, respectively. DBA.44 was detected in 24/42 cases. Seventeen of 37 cases were surface IgD (SIgD)-positive. Twenty-one of 22 analyzed cases were SIgM-positive (12/21 coexpressed SIgD). Five of 37 cases were SIgG-positive. CD27 staining was observed in 21/35 cases; 7/18 CD27-positive cases coexpressed SIgD; 7/14 CD27-negative cases were SIgD-positive. Forty IGHV-D-J rearrangements were amplified in 34/42 cases: the IGHV4-34 gene predominated, followed by IGHV1-2. Using the 98% homology cut-off, 25/40 (62.5%) IGHV sequences were considered as "mutated": 10/11 cases with monomorphous, marginal-zone morphology were IGHV-mutated; in contrast, 4/6 cases with monomorphous, small-cell morphology were IGHV-unmutated. Five of 7 cases expressing IGHV1 subgroup genes had biphasic morphology, whereas 6/9 IGHV3-expressing cases had monomorphous, marginal-zone morphology. Most IGHV-mutated cases (14/20; 70%) were SIgD-negative; in contrast, 8/11 IGHV-unmutated cases expressed SIgD. CD27 was detected in 10/17 IGHV-mutated and 6/10 IGHV-unmutated cases. Seven of 11 CD27-negative cases were IGHV-mutated; 5/7 CD27-negative/IGHV-mutated cases expressed DBA.44. These results confirm the considerable histologic, immunohistochemical, and molecular heterogeneity of SMZL and indicate an origin from the diverse resident B-cell populations of the normal SMZ.

Immunoglobulin heavy- and light-chain repertoire in splenic marginal zone lymphoma

The considerable heterogeneity in morphology, immunophenotype, genotype, and clinical behavior of splenic marginal zone lymphoma (SMZL) hinders firm conclusions on the origin and differentiation stage of the neoplastic cells. Immunoglobulin (IG) gene usage and somatic mutation patterns were studied in a series of 43 SMZL cases. Clonal IGHV-D-J rearrangements were amplified in 42/43 cases (4 cases carried double rearrangements). Among IGHV-D-J rearrangements, IGHV3 and IGHV4 subgroup genes were used with the highest frequency. Nineteen IGHV genes were unmutated (> 98% homology to the closest germline IGHV gene), whereas 27/46 were mutated. Clonal IGKV-J and IGLV-J gene rearrangements were amplified in 36/43 cases, including 31 IGKV-J (8/31 in lambda light-chain expressing cases) and 12 IGLV-J rearrangements; 9/31 IGKV and 6/12 IGLV sequences were mutated. IGKV-J and IGLV-J rearrangements used 14 IGKV and 9 IGLV different germline genes. Significant evidence for positive selection by classical T-dependent antigen was found in only 5/27 IGHV and 6/15 IGKV+IGLV mutated genes. These results provide evidence for the diverse B-cell subpopulations residing in the SMZ, which could represent physiologic equivalents of distinct SMZL subtypes. Furthermore, they indicate that in SMZL, as in other B cell malignancies, a complementarity imprint of antigen selection might be witnessed either by IGHV, IGKV, or IGLV rearranged sequences.

Transferrin receptor-1 and 2 expression in chronic lymphocytic leukemia

Transferrin receptor (TfR)-1 and 2 mRNA and CD71 (TfR1) expression was analyzed in 118 CLL patients. Ninety-five out of 109 analyzed cases expressed CD71, mostly at a high level; 60% of CD71 (+) cases were IGH-mutated. All samples were TfR1 mRNA (+); TfR2-alpha/beta mRNA was detected in, respectively, 52/102 and 100/109 cases. Competitive RT-PCR showed widely divergent levels of TfR1 mRNA in cases with high CD71 expression, alluding to post-transcriptional control of TfR1 expression in CLL. The almost uniformly high CD71 expression in CLL is in keeping with the activated status of neoplastic cells, regardless of IGH mutational load.