Oral Iptacopan Monotherapy in Paroxysmal Nocturnal Hemoglobinuria.

BACKGROUND: Persistent hemolytic anemia and a lack of oral treatments are challenges for patients with paroxysmal nocturnal hemoglobinuria who have received anti-C5 therapy or have not received complement inhibitors. Iptacopan, a first-in-class oral factor B inhibitor, has been shown to improve hemoglobin levels in these patients. METHODS: In two phase 3 trials, we assessed iptacopan monotherapy over a 24-week period in patients with hemoglobin levels of less than 10 g per deciliter. In the first, anti-C5-treated patients were randomly assigned to switch to iptacopan or to continue anti-C5 therapy. In the second, single-group trial, patients who had not received complement inhibitors and who had lactate dehydrogenase (LDH) levels more than 1.5 times the upper limit of the normal range received iptacopan. The two primary end points in the first trial were an increase in the hemoglobin level of at least 2 g per deciliter from baseline and a hemoglobin level of at least 12 g per deciliter, each without red-cell transfusion; the primary end point for the second trial was an increase in hemoglobin level of at least 2 g per deciliter from baseline without red-cell transfusion. RESULTS: In the first trial, 51 of the 60 patients who received iptacopan had an increase in the hemoglobin level of at least 2 g per deciliter from baseline, and 42 had a hemoglobin level of at least 12 g per deciliter, each without transfusion; none of the 35 anti-C5-treated patients attained the end-point levels. In the second trial, 31 of 33 patients had an increase in the hemoglobin level of at least 2 g per deciliter from baseline without red-cell transfusion. In the first trial, 59 of the 62 patients who received iptacopan and 14 of the 35 anti-C5-treated patients did not require or receive transfusion; in the second trial, no patients required or received transfusion. Treatment with iptacopan increased hemoglobin levels, reduced fatigue, reduced reticulocyte and bilirubin levels, and resulted in mean LDH levels that were less than 1.5 times the upper limit of the normal range. Headache was the most frequent adverse event with iptacopan. CONCLUSIONS: Iptacopan treatment improved hematologic and clinical outcomes in anti-C5-treated patients with persistent anemia - in whom iptacopan showed superiority to anti-C5 therapy - and in patients who had not received complement inhibitors. (Funded by Novartis; APPLY-PNH ClinicalTrials.gov number, NCT04558918; APPOINT-PNH ClinicalTrials.gov number, NCT04820530.).

Regulatory B Cells-Immunopathological and Prognostic Potential in Humans.

The aim of the following review is to shed light on the putative role of regulatory B cells (Bregs) in various human diseases and highlight their potential prognostic and therapeutic relevance in humans. Regulatory B cells are a heterogeneous group of B lymphocytes capable of suppressing inflammatory immune reactions. In this way, Bregs contribute to the maintenance of tolerance and immune homeostasis by limiting ongoing immune reactions temporally and spatially. Bregs play an important role in attenuating pathological inflammatory reactions that can be associated with transplant rejection, graft-versus-host disease, autoimmune diseases and allergies but also with infectious, neoplastic and metabolic diseases. Early studies of Bregs identified IL-10 as an important functional molecule, so the IL-10-secreting murine B10 cell is still considered a prototype Breg, and IL-10 has long been central to the search for human Breg equivalents. However, over the past two decades, other molecules that may contribute to the immunosuppressive function of Bregs have been discovered, some of which are only present in human Bregs. This expanded arsenal includes several anti-inflammatory cytokines, such as IL-35 and TGF-ß, but also enzymes such as CD39/CD73, granzyme B and IDO as well as cell surface proteins including PD-L1, CD1d and CD25. In summary, the present review illustrates in a concise and comprehensive manner that although human Bregs share common functional immunosuppressive features leading to a prominent role in various human immunpathologies, they are composed of a pool of different B cell types with rather heterogeneous phenotypic and transcriptional properties.

Triple-fusion protein (TriFu): A potent, targeted, enzyme-like inhibitor of all three complement activation pathways.

The introduction of a therapeutic anti-C5 antibody into clinical practice in 2007 inspired a surge into the development of complement-targeted therapies. This has led to the recent approval of a C3 inhibitory peptide, an antibody directed against C1s and a full pipeline of several complement inhibitors in preclinical and clinical development. However, no inhibitor is available that efficiently inhibits all three complement initiation pathways and targets host cell surface markers as well as complement opsonins. To overcome this, we engineered a novel fusion protein combining selected domains of the three natural complement regulatory proteins decay accelerating factor, factor H and complement receptor 1. Such a triple fusion complement inhibitor (TriFu) was recombinantly expressed and purified alongside multiple variants and its building blocks. We analyzed these proteins for ligand binding affinity and decay acceleration activity by surface plasmon resonance. Additionally, we tested complement inhibition in several in vitro/ex vivo assays using standard classical and alternative pathway restricted hemolysis assays next to hemolysis assays with paroxysmal nocturnal hemoglobinuria erythrocytes. A novel in vitro model of the alternative pathway disease C3 glomerulopathy was established to evaluate the potential of the inhibitors to stop C3 deposition on endothelial cells. Next to the novel engineered triple fusion variants which inactivate complement convertases in an enzyme-like fashion, stoichiometric complement inhibitors targeting C3, C5, factor B, and factor D were tested as comparators. The triple fusion approach yielded a potent complement inhibitor that efficiently inhibits all three complement initiation pathways while targeting to surface markers.

Predictors for improvement in patient-reported outcomes: post hoc analysis of a phase 3 randomized, open-label study of eculizumab and ravulizumab in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by uncontrolled terminal complement activation leading to intravascular hemolysis (IVH), thrombosis, and impairments in quality of life (QoL). The aim of this study was to identify the clinical drivers of improvement in patient-reported outcomes (PROs) in patients with PNH receiving the complement component 5 (C5) inhibitors eculizumab and ravulizumab.This post hoc analysis assessed clinical outcomes and PROs from 246 complement inhibitor-naive patients with PNH enrolled in a phase 3 randomized non-inferiority study that compared the C5 inhibitors ravulizumab and eculizumab (study 301; NCT02946463). The variables of interest were lactate dehydrogenase (LDH) levels, a surrogate measure of IVH, and hemoglobin (Hb) levels. PROs were collected using Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) to assess fatigue and QoL, respectively.Improvements in absolute mean LDH levels were significantly associated with improvements in mean FACIT-F score (p = 0.0024) and EORTC QLQ-C30 global health (GH) score (p < 0.0001) from baseline to day 183. Improvements in scores were achieved despite a non-significant increase in Hb levels. To understand the interaction between LDH and Hb, a regression analysis was performed: LDH response with Hb improvements was a significant predictor of improvement in fatigue. The independent effect of improved Hb did not significantly affect FACIT-F or EORTC QLQ-C30 GH scores.These findings suggest that LDH levels are an important determinant of fatigue and QoL outcomes in patients with PNH. CTR: NCT02946463, October 27, 2016.

Impact of a booster dose on SARS-CoV2 mRNA vaccine-specific humoral-, B- and T cell immunity in pediatric stem cell transplant recipients.

Stem cell transplant recipients (SCTR) are imperiled to increased risks after SARS-CoV2 infection, supporting the need for effective vaccination strategies for this vulnerable group. With respect to pediatric patients, data on immunogenicity of SARS-CoV2 mRNA-based vaccination is limited. We therefore comprehensively examined specific humoral, B- and T cell responses in a cohort of 2-19 year old SCTR after the second and third vaccine dose. Only after booster vaccination, transplant recipients reached similar levels of vaccine-specific IgG, IgA and neutralizing antibodies against omicron variant as age-matched controls. Although frequencies of SARS-CoV2 specific B cells increased after the third dose, they were still fourfold reduced in patients compared to controls. Overall, the majority of individuals enrolled mounted SARS-CoV2 Spike protein-specific CD4+ T helper cell responses with patients showing significantly higher portions than controls after the third dose. With respect to functionality, however, SCTR were characterized by reduced frequencies of specific interferon gamma producing CD4+ T cells, along with an increase in IL-2 producers. In summary, our data identify distinct quantitative and qualitative impairments within the SARS-CoV2 vaccination specific B- and CD4+ T cell compartments. More importantly, humoral analyses highlight the need for a booster vaccination of SCTR particularly for development of neutralizing antibodies.

Real-world data suggest effectiveness of the allogeneic mesenchymal stromal cells preparation MSC-FFM in ruxolitinib-refractory acute graft-versus-host disease.

BACKGROUND: Patients with steroid-refractory acute graft-versus-host disease (aGvHD) not tolerating/responding to ruxolitinib (RR-aGvHD) have a dismal prognosis. METHODS: We retrospectively assessed real-world outcomes of RR-aGvHD treated with the random-donor allogeneic MSC preparation MSC-FFM, available via Hospital Exemption in Germany. MSC-FFM is provided as frozen cell dispersion for administration as i.v. infusion immediately after thawing, at a recommended dose of 1-2 million MSCs/kg body weight in 4 once-weekly doses. 156 patients, 33 thereof children, received MSC-FFM; 5% had Grade II, 40% had Grade III, and 54% had Grade IV aGvHD. Median (range) number of prior therapies was 4 (1-10) in adults and 7 (2-11) in children. RESULTS: The safety profile of MSC-FFM was consistent with previous reports for MSC therapies in general and MSC-FFM specifically. The overall response rate at Day 28 was 46% (95% confidence interval [CI] 36-55%) in adults and 64% (45-80%) in children; most responses were durable. Probability of overall survival at 6, 12 and 24 months was 47% (38-56%), 35% (27-44%) and 30% (22-39%) for adults, and 59% (40-74%), 42% (24-58%) and 35% (19-53%) for children, respectively (whole cohort: median OS 5.8 months). CONCLUSION: A recent real-world analysis of outcomes for 64 adult RR-aGvHD patients not treated with MSCs reports survival of 20%, 16% and 10% beyond 6, 12 and 24 months, respectively (median 28 days). Our data thus suggest effectiveness of MSC-FFM in RR-aGvHD.

SARS-CoV-2 mRNA vaccination-induced immunological memory in human nonlymphoid and lymphoid tissues.

Tissue-resident lymphocytes provide organ-adapted protection against invading pathogens. Whereas their biology has been examined in great detail in various infection models, their generation and functionality in response to vaccination have not been comprehensively analyzed in humans. We therefore studied SARS-CoV-2 mRNA vaccine-specific T cells in surgery specimens of kidney, liver, lung, bone marrow, and spleen compared with paired blood samples from largely virus-naive individuals. As opposed to lymphoid tissues, nonlymphoid organs harbored significantly elevated frequencies of spike-specific CD4+ T cells compared with blood showing hallmarks of tissue residency and an expanded memory pool. Organ-derived CD4+ T cells further exhibited increased polyfunctionality over those detected in blood. Single-cell RNA-Seq together with T cell receptor repertoire analysis indicated that the clonotype rather than organ origin is a major determinant of transcriptomic state in vaccine-specific CD4+ T cells. In summary, our data demonstrate that SARS-CoV-2 vaccination entails acquisition of tissue memory and residency features in organs distant from the inoculation site, thereby contributing to our understanding of how local tissue protection might be accomplished.

Phorbol-12-myristate-13-acetate is a potent enhancer of B cells with a granzyme B+ regulatory phenotype.

Introduction: The infusion of ex-vivo-generated regulatory B cells may represent a promising novel therapeutic approach for a variety of autoimmune and hyperinflammatory conditions including graft-versus-host disease. Methods: Previously, we developed a protocol for the generation of a novel population of regulatory B cells, which are characterized by secretion of enzymatically active granzyme B (GraB cells). This protocol uses recombinant interleukin 21 (IL-21) and goat-derived F(ab)'2 fragments against the human B cell receptor (anti-BCR). Generally, the use of xenogeneic material for the manufacturing of advanced therapy medicinal products should be avoided to prevent adverse immune reactions as well as potential transmission of so far unknown diseases. Results: In the present work we demonstrated that phorbol-12-myristate-13-acetate (PMA/TPA), a phorbol ester with a particular analogy to the second messenger diacylglycerol (DAG), is a potent enhancer of IL-21-induced differentiation of pre-activated B cells into GraB cells. The percentage of GraB cells after stimulation of pre-activated B cells with IL-21 and PMA/TPA was not significantly lower compared to stimulation with IL-21 and anti-BCR. Discussion: Given that PMA/TPA has already undergone encouraging clinical testing in patients with certain haematological diseases, our results suggest that PMA/TPA may be a safe and feasible alternative for ex-vivo manufacturing of GraB cells.

AML with complex karyotype: extreme genomic complexity revealed by combined long-read sequencing and Hi-C technology.

Acute myeloid leukemia with complex karyotype (CK-AML) is associated with poor prognosis, which is only in part explained by underlying TP53 mutations. Especially in the presence of complex chromosomal rearrangements, such as chromothripsis, the outcome of CK-AML is dismal. However, this degree of complexity of genomic rearrangements contributes to the leukemogenic phenotype and treatment resistance of CK-AML remains largely unknown. Applying an integrative workflow for the detection of structural variants (SVs) based on Oxford Nanopore (ONT) genomic DNA long-read sequencing (gDNA-LRS) and high-throughput chromosome confirmation capture (Hi-C) in a well-defined cohort of CK-AML identified regions with an extreme density of SVs. These rearrangements consisted to a large degree of focal amplifications enriched in the proximity of mammalian-wide interspersed repeat elements, which often result in oncogenic fusion transcripts, such as USP7::MVD, or the deregulation of oncogenic driver genes as confirmed by RNA-seq and ONT direct complementary DNA sequencing. We termed this novel phenomenon chromocataclysm. Thus, our integrative SV detection workflow combing gDNA-LRS and Hi-C enables to unravel complex genomic rearrangements at a very high resolution in regions hard to analyze by conventional sequencing technology, thereby providing an important tool to identify novel important drivers underlying cancer with complex karyotypic changes.

Effect of Expansion Media on Functional Characteristics of Bone Marrow-Derived Mesenchymal Stromal Cells.

The therapeutic efficacy of mesenchymal stromal cells (MSCs) has been shown to rely on their immunomodulatory and regenerative properties. In order to obtain sufficient numbers of cells for clinical applications, MSCs have to be expanded ex vivo. Expansion media with xenogeneic-free (XF) growth-promoting supplements like human platelet lysate (PL) or serum- and xenogeneic-free (SF/XF) formulations have been established as safe and efficient, and both groups provide different beneficial qualities. In this study, MSCs were expanded in XF or SF/XF media as well as in mixtures thereof. MSCs cultured in these media were analyzed for phenotypic and functional properties. MSC expansion was optimal with SF/XF conditions when PL was present. Metabolic patterns, consumption of growth factors, and secretome of MSCs differed depending on the type and concentration of supplement. The lactate per glucose yield increased along with a higher proportion of PL. Many factors in the supernatant of cultured MSCs showed distinct patterns depending on the supplement (e.g., FGF-2, TGFß, and insulin only in PL-expanded MSC, and leptin, sCD40L PDGF-AA only in SF/XF-expanded MSC). This also resulted in changes in cell characteristics like migratory potential. These findings support current approaches where growth media may be utilized for priming MSCs for specific therapeutic applications.

Complement and platelets: prothrombotic cell activation requires membrane attack complex-induced release of danger signals.

Complement activation in the diseases paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS) results in cytolysis and fatal thrombotic events, which are largely refractory to anticoagulation and/or antiplatelet therapy. Anticomplement therapy, however, efficiently prevents thrombotic events in PNH and aHUS, but the underlying mechanisms remain unresolved. We show that complement-mediated hemolysis in whole blood induces platelet activation similarly to activation by adenosine 5'-diphosphate (ADP). Blockage of C3 or C5 abolished platelet activation. We found that human platelets failed to respond functionally to the anaphylatoxins C3a and C5a. Instead, complement activation did lead to prothrombotic cell activation in the whole blood when membrane attack complex (MAC)-mediated cytolysis occurred. Consequently, we demonstrate that ADP receptor antagonists efficiently inhibited platelet activation, although full complement activation, which causes hemolysis, occurred. By using an established model of mismatched erythrocyte transfusions in rats, we crossvalidated these findings in vivo using the complement inhibitor OmCI and cobra venom factor. Consumptive complement activation in this animal model only led to a thrombotic phenotype when MAC-mediated cytolysis occurred. In conclusion, complement activation only induces substantial prothrombotic cell activation if terminal pathway activation culminates in MAC-mediated release of intracellular ADP. These results explain why anticomplement therapy efficiently prevents thromboembolisms without interfering negatively with hemostasis.

Quality assessment and harmonization of laboratories across Europe for multiple SARS-CoV-2 serology assays.

BACKGROUND AND OBJECTIVES: There is a need for conversion of SARS-CoV-2 serology data from different laboratories to a harmonized international unit. We aimed to compare the performance of multiple SARS-CoV-2 antibody serology assays among 25 laboratories across 12 European countries. MATERIALS AND METHODS: To investigate this we have distributed to all participating laboratories a panel of 15 SARS-CoV-2 plasma samples and a single batch of pooled plasma calibrated to the WHO IS 20/136 standard. RESULTS: All assays showed excellent discrimination between SARS-CoV-2 seronegative plasma samples and pre-vaccinated seropositive plasma samples but differed substantially in raw antibody titres. Titres could be harmonized to binding antibody units per millilitre by calibration in relation to a reference reagent. CONCLUSION: The standardization of antibody quantification is of paramount importance to allow interpretation and comparison of serology data reported in clinical trials in order to identify donor cohorts from whom the most effective convalescent plasma can be collected.

Serum sPD-L1 levels are elevated in patients with viral diseases, bacterial sepsis or in patients with impaired renal function compared to healthy blood donors.

OBJECTIVES: Immune checkpoints play an important role in maintaining the balance of the immune system and in the development of autoimmune diseases. A central checkpoint molecule is the programmed cell death protein 1 (PD-1, CD279) which is typically located on the surface of T cells. Its primary ligand PD-L1 is expressed on antigen presenting cells and on cancer cells. Several variants of PD-L1 exist, among these soluble molecules (sPD-L1) present in serum at low concentrations. sPD-L1 was found elevated in cancer and several other diseases. sPD-L1 in infectious diseases has received relatively little attention so far and is therefore subject of this study. METHODS: sPD-L1 serum levels were determined in 170 patients with viral infections (influenza, varicella, measles, Dengue fever, SARS-CoV2) or bacterial sepsis by ELISA and compared to the levels obtained in 11 healthy controls. RESULTS: Patients with viral infections and bacterial sepsis generally show significantly higher sPD-L1 serum levels compared to healthy donors, except for varicella samples where results do not reach significance. sPD-L1 is increased in patients with impaired renal function compared to those with normal renal function, and sPD-L1 correlates significantly with serum creatinine. Among sepsis patients with normal renal function, sPD-L1 serum levels are significantly higher in Gram-negative sepsis compared to Gram-positive sepsis. In addition, in sepsis patients with impaired renal function, sPD-L1 correlates positively with ferritin and negatively with transferrin. CONCLUSIONS: sPD-L1 serum levels are significantly elevated in patients with sepsis, influenza, mesasles, Dengue fever or SARS-CoV2. Highest levels are detectable in patients with measles and Dengue fever. Also impaired renal function causes an increase in levels of sPD-L1. As a consequence, renal function has to be taken into account in the interpretation of sPD-L1 levels in patients.

Clinically important change for the FACIT-Fatigue scale in paroxysmal nocturnal hemoglobinuria: a derivation from international PNH registry patient data.

BACKGROUND: Fatigue is the most common symptom associated with paroxysmal nocturnal hemoglobinuria (PNH). The objective of this analysis was to estimate values that would suggest a clinically important change (CIC) for the functional assessment of chronic illness therapy-fatigue scale (FACIT-Fatigue) in patients with PNH. METHODS: Adults with PNH who initiated eculizumab within 28 days of enrollment in the International PNH Registry as of January 2021 with baseline FACIT-Fatigue scores were included in the analysis. Distribution-based estimates of likely difference were calculated using 0.5 × SD and SEM. Anchor-based estimates of CIC considered the European Organization for Research and Treatment of Cancer (EORTC) global health status/quality of life summary score and the EORTC Fatigue Scale score. Changes in anchors and high disease activity (HDA) shift from start of eculizumab treatment to each follow-up visit were then assessed by FACIT-Fatigue score change (≤ 1 CIC, no change, or ≥ 1 CIC). RESULTS: At baseline, 93% of 423 patients had fatigue documented in their medical history. The distribution-based estimates for FACIT-Fatigue were 6.5 using 0.5 × SD and 4.6 using SEM; internal consistency was high (α = 0.87). For anchor-based estimates, the FACIT-Fatigue CIC ranged from 2.5 to 15.5, and generally supported 5 points as a reasonable lower end of the value for meaningful individual change. The percentage of patients who changed from having HDA at baseline to no HDA at eculizumab-treated follow-up visits increased over time. CONCLUSION: These results support the use of 5 points as the CIC for FACIT-Fatigue in patients with PNH, which is within range of the CICs reported in other diseases (3-5 points).

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disease that leads to breakdown of the body's red blood cells in the blood vessels (intravascular hemolysis). Many people with PNH have fatigue, which consists of tiredness and weakness. A self-report questionnaire called the FACIT-Fatigue scale that objectively measures how fatigued a patient feels has been validated in clinical trials. Changes in the FACIT-Fatigue score help determine if a treatment is helping patients. The clinically important difference (difference between groups of people) or clinically important change (change within an individual) on the FACIT-Fatigue scale is a value that helps patients and clinicians find out if a drug helps or worsens patient fatigue. There is currently no defined clinically important difference and clinically important change on the FACIT-Fatigue scale for people with PNH. The International PNH Registry is a noninterventional, observational study collecting safety, treatment outcomes, and quality of life data from adults with PNH. This study used data from the International PNH Registry to find a clinically important difference and clinically important change in terms of improvement on the FACIT-Fatigue scale for adults with PNH who started eculizumab treatment. Different approaches were used to determine the amount of change in FACIT-Fatigue that would show that eculizumab has meaningful benefits, meaning patients are less fatigued. The authors demonstrated that a 5-point change on the FACIT-Fatigue is meaningful for people with PNH. This number is similar to the clinically important difference and clinically important change values of 3­5 points determined in other diseases.

Correlation between Clinical Characteristics and Antibody Levels in COVID-19 Convalescent Plasma Donor Candidates.

COVID-19 convalescent plasma (CCP) with high neutralizing antibodies has been suggested in preventing disease progression in COVID-19. In this study, we investigated the relationship between clinical donor characteristics and neutralizing anti-SARS-CoV-2 antibodies in CCP donors. COVID-19 convalescent plasma donors were included into the study. Clinical parameters were recorded and anti-SARS-CoV-2 antibody levels (Spike Trimer, Receptor Binding Domain (RBD), S1, S2 and nucleocapsid protein) as well as ACE2 binding inhibition were measured. An ACE2 binding inhibition < 20% was defined as an inadequate neutralization capacity. Univariate and multivariable logistic regression analysis was used to detect the predictors of inadequate neutralization capacity. Ninety-one CCP donors (56 female; 61%) were analyzed. A robust correlation between all SARS-CoV-2 IgG antibodies and ACE2 binding inhibition, as well as a positive correlation between donor age, body mass index, and a negative correlation between time since symptom onset and antibody levels were found. We identified time since symptom onset, normal body mass index (BMI), and the absence of high fever as independent predictors of inadequate neutralization capacity. Gender, duration of symptoms, and number of symptoms were not associated with SARS-CoV-2 IgG antibody levels or neutralization. Neutralizing capacity was correlated with SARS-CoV-2 IgG antibodies and associated with time since symptom onset, BMI, and fever. These clinical parameters can be easily incorporated into the preselection of CCP donors.

Crovalimab treatment in patients with paroxysmal nocturnal haemoglobinuria: Long-term results from the phase I/II COMPOSER trial.

OBJECTIVES: This study reports long-term outcomes from the open-label extension (OLE) period of the Phase I/II COMPOSER trial (NCT03157635) that evaluated crovalimab in patients with paroxysmal nocturnal haemoglobinuria, who were treatment-naive or switched from eculizumab at enrolment. METHODS: COMPOSER consists of four sequential parts followed by the OLE. The primary OLE objective was to assess long-term crovalimab safety, with a secondary objective to assess crovalimab pharmacokinetics and pharmacodynamics. Exploratory efficacy endpoints included change in lactate dehydrogenase (LDH), transfusion avoidance, haemoglobin stabilisation and breakthrough haemolysis (BTH). RESULTS: A total 43 of 44 patients entered the OLE after completing the primary treatment period. Overall, 14 of 44 (32%) experienced treatment-related adverse events. Steady state exposure levels of crovalimab and terminal complement inhibition were maintained over the OLE. During the OLE, mean normalised LDH was generally maintained at ≤1.5× upper limit of normal, transfusion avoidance was achieved in 83%-92% of patients and haemoglobin stabilisation was reached in 79%-88% of patients across each 24-week interval. Five BTH events occurred with none leading to withdrawal. CONCLUSIONS: Over a 3-year median treatment duration, crovalimab was well tolerated and sustained C5 inhibition was achieved. Intravascular haemolysis control, haemoglobin stabilisation and transfusion avoidance were maintained, signifying long-term crovalimab efficacy.

A Combination of the Immunotherapeutic Drug Anti-Programmed Death 1 with Lenalidomide Enhances Specific T Cell Immune Responses against Acute Myeloid Leukemia Cells.

Immune checkpoint inhibitors can block inhibitory molecules on the surface of T cells, switching them from an exhausted to an active state. One of these inhibitory immune checkpoints, programmed cell death protein 1 (PD-1) is expressed on T cell subpopulations in acute myeloid leukemia (AML). PD-1 expression has been shown to increase with AML progression following allo-haematopoeitic stem cell transplantation, and therapy with hypomethylating agents. We have previously shown that anti-PD-1 can enhance the response of leukemia-associated antigen (LAA)-specific T cells against AML cells as well as leukemic stem and leukemic progenitor cells (LSC/LPCs) ex vivo. In concurrence, blocking of PD-1 with antibodies such as nivolumab has been shown to enhance response rates post-chemotherapy and stem cell transplant. The immune modulating drug lenalidomide has been shown to promote anti-tumour immunity including anti-inflammatory, anti-proliferative, pro-apoptotic and anti-angiogenicity. The effects of lenalidomide are distinct from chemotherapy, hypomethylating agents or kinase inhibitors, making lenalidomide an attractive agent for use in AML and in combination with existing active agents. To determine whether anti-PD-1 (nivolumab) and lenalidomide alone or in combination could enhance LAA-specific T cell immune responses, we used colony-forming immune and ELISpot assays. Combinations of immunotherapeutic approaches are believed to increase antigen-specific immune responses against leukemic cells including LPC/LSCs. In this study we used a combination of LAA-peptides with the immune checkpoint inhibitor anti-PD-1 and lenalidomide to enhance the killing of LSC/LPCs ex vivo. Our data offer a novel insight into how we could improve AML patient responses to treatment in future clinical studies.

KIR2DS4 and Its Variant KIR1D in KIR-AA Genotype Donors Showed Differential Survival Impact in Patients with Lymphoid Disease after HLA-Matched Unrelated Hematopoietic Stem Cell Transplantation.

Previous studies have illustrated associations between the presence of activating killer cell immunoglobulin-like receptor (KIR) genes and lower susceptibility to hematologic malignancies in humans. In addition, favorable hematopoietic stem cell transplantation (HSCT) outcomes have been reported in patients who received transplants from donors with KIR genotypes dominant for activating KIR receptors. However, the association of activating KIR genes on an allelic level with disease and their impact on HSCT outcome has been little investigated to date. To this end, we genotyped a large transplantation cohort for KIR 2 Ig domains and short cytoplasmic tail 4 (KIR2DS4) polymorphisms and investigated their association with disease. We next investigated the impact of KIR-AA genotype donor KIR2DS4 polymorphisms (AA/KIR2DS4 versus AA/ KIR 1 Ig domain [KIR1D]) on clinical outcomes of HSCT in myeloid versus lymphoid patient subgroups. Among 2810 transplantation donor-recipient pairs, 68.8% (n = 1934) were 10/10 HLA-matched and 31.2% (n = 876) were 9/10 HLA-matched. The distribution of KIR1D was equal in patients and donors (P = .205). Multivariate analysis in 10/10 HLA-matched patients with lymphoid disease showed improved HSCT outcomes when they received grafts from AA/KIR1D donors (overall survival: hazard ratio [HR], .62, P = .002; disease free survival: HR, .70, P = .011; graft-versus-host disease-free and relapse-free survival: HR, .67, P = .002; nonrelapse mortality: HR, .55, P < .001). This effect was not seen in either 9/10 HLA-matched patients with lymphoid disease or patients with myeloid disease. Our study indicates that the presence of KIR1D alleles is not associated with disease in patients, and, interestingly, using grafts from AA/KIR1D donors translated into beneficial survival outcomes in 10/10 HLA-matched patients with lymphoid disease.

SARS-CoV-2 vaccination of convalescents boosts neutralization capacity against Omicron subvariants BA.1, BA.2 and BA.5 and can be predicted by anti-S antibody concentrations in serological assays.

Background: Recent data on immune evasion of new SARS-CoV-2 variants raise concerns about the efficacy of antibody-based COVID-19 therapies. Therefore, in this study the in-vitro neutralization capacity against SARS-CoV-2 variant B.1 and the Omicron subvariants BA.1, BA.2 and BA.5 of sera from convalescent individuals with and without boost by vaccination was assessed. Methods and findings: The study included 313 serum samples from 155 individuals with a history of SARS-CoV-2 infection, divided into subgroups without (n=25) and with SARS-CoV-2 vaccination (n=130). We measured anti-SARS-CoV-2 antibody concentrations by serological assays (anti-SARS-CoV-2-QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S) and neutralizing titers against B.1, BA.1, BA.2 and BA.5 in a pseudovirus neutralization assay. Sera of the majority of unvaccinated convalescents did not effectively neutralize Omicron sublineages BA.1, BA.2 and BA.5 (51.7%, 24.1% and 51.7%, resp.). In contrast, 99.3% of the sera of superimmunized individuals (vaccinated convalescents) neutralized the Omicron subvariants BA.1 and BA.5 and 99.6% neutralized BA.2. Neutralizing titers against B.1, BA.1, BA.2 and BA.5 were significantly higher in vaccinated compared to unvaccinated convalescents (p<0.0001) with 52.7-, 210.7-, 141.3- and 105.4-fold higher geometric mean of 50% neutralizing titers (NT50) in vaccinated compared to unvaccinated convalescents. 91.4% of the superimmunized individuals showed neutralization of BA.1, 97.2% of BA.2 and 91.5% of BA.5 with a titer ≥ 640. The increase in neutralizing titers was already achieved by one vaccination dose. Neutralizing titers were highest in the first 3 months after the last immunization event. Concentrations of anti-S antibodies in the anti-SARS-CoV-2-QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S assays predicted neutralization capacity against B.1 and Omicron subvariants BA.1, BA.2 and BA.5. Conclusions: These findings confirm substantial immune evasion of the Omicron sublineages, which can be overcome by vaccination of convalescents. This informs strategies for choosing of plasma donors in COVID-19 convalescent plasma programs that shall select specifically vaccinated convalescents with very high titers of anti-S antibodies.