Complement inhibition in paroxysmal nocturnal hemoglobinuria: From biology to therapy.

Complement inhibitors are the mainstay of paroxysmal nocturnal hemoglobinuria (PNH) treatment. The anti-C5 monoclonal antibody eculizumab was the first treatment to improve hemolysis, thrombotic risk, and survival in PNH although at the price of a life-long intravenous fortnightly drug. Additionally, suboptimal response may occur in up to 2/3 of patients with persistent anemia due to incomplete control of intravascular hemolysis, development of upstream C3-mediated extravascular hemolysis (EVH), or concomitant bone marrow failure. Ravulizumab, a longer half-life anti-C5 developed from eculizumab, administered every 8 weeks, improved patient convenience, and reduced pharmacokinetic breakthrough hemolysis (BTH) by establishing more stable anti-C5 concentrations. More recently, several other anti-C5 compounds (crovalimab, pozelimab, tesidolumab, cemdisiran, zilucoplan, and coversin) are on study in clinical trials. Upstream inhibition of complement cascade was also explored with the anti-C3 pegcetacoplan, and with the alternative pathway inhibitors iptacopan (anti-factor B) and danicopan (anti-factor D). These drugs efficiently target EVH and are able to improve anemia and transfusion need in suboptimal responders to anti-C5. The route and schedule of administration (twice weekly subcutaneously for pegcetacoplan and twice or thrice oral daily dosing for iptacopan and danicopan, respectively) are very convenient but pose novel issues regarding adherence. Additionally, both anti-C5 and upstream inhibitors do not resolve the unmet need of pharmacodynamic BTH events due to complement amplifying conditions such as infections, traumas, and surgery. In this review, we will recapitulate PNH physiopathology, clinical presentation, and diagnosis and describe available and developing drugs that will lead to a precision medicine approach for this rare though heterogenous disease.

Glycolytic activity and in vitro effect of the pyruvate kinase activator AG-946 in red blood cells from low-risk myelodysplastic syndromes patients: A proof-of-concept study.

Glycolytic activity and in vitro effect of the pyruvate kinase activator AG-946 in red blood cells from low-risk myelodysplastic syndromes patients. Data showed decreased glycolytic activity in red blood cells of 2/3 of patients with lower-risk MDS. These results highlight a potential effect of the PK activator in this setting.

Daratumumab monotherapy in refractory warm autoimmune hemolytic anemia and cold agglutinin disease.

Autoimmune hemolytic anemia (AIHA) is a rare autoantibody-mediated disease. For steroid and/or rituximab-refractory AIHA, there is no consensus on optimal treatment. Daratumumab, a monoclonal antibody targeting CD38, could be beneficial by suppression of CD38+ plasmacells and thus autoantibody secretion. In addition, since CD38 is also expressed by activated T-cells, daratumumab may also act via immunomodulatory effects. We evaluated efficacy and safety of daratumumab monotherapy in an international retrospective study including 19 adult patients with heavily pretreated refractory AIHA. In warm AIHA (wAIHA, n=12), overall response was 50% with a median response duration of 5.5 months (range, 2-12 months) including ongoing response in 2 patients after 6 and 12 months. Of 6 non-responders, 4 had Evans syndrome. In cold AIHA (cAIHA, n=7) overall hemoglobin (Hb) response was 57%, with ongoing response in 3/7 patients. One additional non-anemic cAIHA patient was treated for severe acrocyanosis and reached a clinical acrocyanosis response as well as a Hb increase. Of 6 cAIHA patients with acrocyanosis, 4 had improved symptoms after daratumumab treatment. In two patients with wAIHA treated with daratumumab in whom we prospectively collected blood samples, we found complete CD38+ T cells depletion after daratumumab, as well as altered T-cell subset differentiation and a severely diminished capacity for cell activation and proliferation. Reappearance of CD38+ T-cells coincided with disease relapse in one patient. In conclusion, our data show that daratumumab therapy may be a treatment option for refractory AIHA. The observed immunomodulatory effects that may contribute to the clinical response deserve further exploration.

COVID-19 vaccine safety and immunogenicity in patients with cold agglutinin disease receiving concomitant sutimlimab.

Patients with cold agglutinin disease (CAD) are more vulnerable to infectious agents, thus the COVID-19 pandemic has posed a particular risk to this population. Sutimlimab Phase 3 studies CARDINAL and CADENZA spanned the period before and during the pandemic; investigators were advised to vaccinate enrolled patients without stopping treatment. Of 61 completers from both studies, 47 received ≥1 dose of a COVID-19 vaccine. In the immunogenicity analysis (n = 27) all patients developed an immune response post-COVID-19 vaccination, with detectable immunoglobulin G anti-spike antibodies. Analysis of six patients with booster vaccinations demonstrated increased immune responses pre- to post-booster. COVID-19 vaccines were well tolerated in patients with CAD receiving sutimlimab treatment, and no signs of hemolytic exacerbations were observed post-vaccination.

Deciphering cytopenias in internal medicine: a single-center observational study.

Cytopenia is a common finding in patients admitted to internal medicine wards and the clinical workup may be long and time-consuming. In this single-center observational study, we analyzed a series of 151 inpatients who received hematologist referral due to cytopenia observed during hospital admission. Patients were mainly elderly (median 71 years, 15-96) and 87% had at least one comorbidity. Anemia was the most common cytopenia (91%), followed by thrombocytopenia (51%), and neutropenia (22%); 73 (48%) patients had a bicytopenia and 5 (3%) pancytopenia. Cytopenias were mainly severe, 66% of cases required RBC transfusions, and 21% platelet pools. During a median hospital stay of 15 days (1-166), 53 subjects (35%) received a hematologic discharge diagnosis, whilst the two-thirds had secondary cytopenia mainly due to associated comorbidities. Only about 34% of 2,728 diagnostic tests performed (including laboratory, imaging, and histology) clearly informed the discharge diagnosis in this heterogenous setting. Specifically, bone-marrow evaluation indicated in 46 (30%) patients, was diagnostic in 32 (69.6%). Eleven percent of patients died due to progression of the oncohematologic disease (29%), sepsis (24%), and solid tumor progression (24%). In conclusion, cytopenias in the internal medicine setting are mainly severe, more frequently secondary to associated comorbidities (2/3 of patients) and deserve proper workup before second/third-level tests (immune-hematological assays and CT scan or PET and bone-marrow evaluation, respectively).

Current use of androgens in bone marrow failure disorders: a report from the Severe Aplastic Anemia Working Party of the European Society for Blood and Marrow Transplantation.

Androgens represent the historical therapeutic backbone of bone marrow failure (BMF) syndromes. However, their role has rarely been analyzed in a prospective setting, and systematic and long-term data regarding their usage, effectiveness and toxicity in both acquired and inherited BMF are currently unavailable. Here, taking advantage of a unique disease-specific international dataset, we retrospectively analyzed the largest cohort so far of BMF patients who received androgens before or in the absence of an allogeneic hematopoietic cell transplantation (HCT), re-evaluating their current use in these disorders. We identified 274 patients across 82 European Society for Blood and Marrow Transplantation (EBMT) affiliated centers: 193 with acquired (median age 32 years) and 81 with inherited (median age 8 years) BMF. With a median duration of androgen treatment of 5.6 and 20 months, respectively, complete and partial remission rates at 3 months were 6% and 29% in acquired and 8% and 29% in inherited disorders. Five-year overall survival and failure-free survival (FFS) were respectively 63% and 23% in acquired and 78% and 14% in inherited BMF. Androgen initiation after second-line treatments for acquired BMF, and after >12 months post diagnosis for inherited BMF were identified as factors associated with improved FFS in multivariable analysis. Androgen use was associated with a manageable incidence of organ-specific toxicity, and low rates of solid and hematologic malignancies. Sub-analysis of transplant-related outcomes after exposure to these compounds showed probabilities of survival and complications similar to other transplanted BMF cohorts. This study delivers a unique opportunity to track androgen use in BMF syndromes and represents the basis for general recommendations on this category of therapeutics on behalf of the Severe Aplastic Anemia Working Party of the EBMT.

Transfusions in autoimmune hemolytic anemias: Frequency and clinical significance of alloimmunization.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) may be associated with transfusion reactions and risk of alloimmunization. OBJECTIVES: To evaluate the transfusion policy and rate of alloimmunization and its clinical significance in AIHA. METHODS: Data from 305 AIHA patients followed at a reference hematologic Center in Milan, Italy from 1997 to 2022 were retrospectively/prospectively collected (NCT05931718). RESULTS: Overall, 33% patients required transfusions with a response rate of 83% and eight transfusion reactions (7%), none hemolytic. Alloantibodies were detected in 19% of patients, being associated with higher transfusion burden (p = 0.01), lower Hb increase post-transfusion (p = 0.05), and transfusion reactions (p = 0.04). Along decades, the rate of RBC transfusions decreased from 53% to 20% and that of alloimmunization dropped from 30% to 6% likely due to the adoption of prestorage leukoreduction, the use of more restrictive Hb thresholds, and the implementation of molecular typing. CONCLUSIONS: Severe symptomatic AIHA may be safely transfused provided appropriate matching of patients and donors.

Recombinant erythropoietin in autoimmune hemolytic anemia with inadequate bone marrow response: a prospective analysis.

ABSTRACT: Up to 30% of patients with autoimmune hemolytic anemia (AIHA) show inadequate bone marrow (BM) compensatory response with inappropriately low levels of reticulocytes and endogenous erythropoietin. Ineffective BM compensation is associated with more severe anemia, transfusion need, and hospital admission, and treatment with recombinant erythropoietin (rEPO) may be beneficial. Here, we prospectively analyzed the efficacy and safety of rEPO in a single-center cohort of 47 patients with AIHA with inadequate reticulocytosis and endogenous erythropoietin at baseline. Epoetin alpha 40 000 international units per week were administered subcutaneously until hemoglobin (Hb) >11 g/dL and then tapered off. Overall response was 55% at 15 days, 74% at 1 month, 74% at 3 months, 80% at 6 months, and 91% at 12 months. Consistently, Hb values significantly increased from baseline to each subsequent time point (P<.001) with a median increase of +1.4, +2.4, +3.4, +3.8, and +4.4 g/dL, respectively. Transfusion needs reduced from 30% to <10% at 15 days and thereafter (P < .001). Concomitant medications included prednisone or methylprednisolone (N = 40, stable since >2 weeks from enrollment), mycophenolate mofetil (N = 1, ongoing since >3 months from enrollment), and rituximab (N = 7 patients with cold agglutinin disease from day 8). No association between concomitant medications and response to rEPO was found. Treatment was generally safe without rEPO-related severe adverse events. The comparison with an AIHA population not treated with rEPO showed a significant benefit of rEPO at 15 days and 1 month on response and Hb increase. These data support the use of rEPO as an add on to standard immunosuppression in AIHA with inadequate BM compensation. This trial was registered at www.clinicaltrials.gov as #NCT05931718.

Cytokine polymorphisms in patients with autoimmune hemolytic anemia.

Autoimmune hemolytic anemia (AIHA) is due to autoantibodies with or without complement activation and involves cellular and cytokine dysregulation. Here, we investigated cytokine single-nucleotide polymorphisms (SNPs) of TNF-α, TGF-ß1, IL-10, IL-6, and IFN-γ, along with their serum levels. The former were related to hematological parameters, therapy, and clinical outcome. The study included 123 consecutive patients with primary AIHA [77 warm AIHA and 46 cold agglutinin disease (CAD)], followed up for a median of 49 months. Results show that the allelic frequency of TNF-α -308 G/A polymorphisms was significantly lower in patients versus controls. Moreover, the genotypic frequency of TNF-α -308G/A and TGF-ß gene codon 25 G/C genotypes was significantly lower in patients versus controls. Considering cytokine SNP genotypes associated with different gene expression levels, TNF-α high gene expression was significantly more frequent in patients, TGF-ß and IL-10 high gene expression was higher in patients with more severe anemia, and TGF-ß high gene expression was higher in patients with active disease. Considering treatment, TNF-α and TGF-ß high gene expression was more frequent in multitreated patients and particularly in CAD. It may be speculated that this genetic predisposition to a stronger inflammatory response may result in a greater immune dysregulation and in a relapsed/refractory disease. Regarding cytokine serum levels, TNF-α and TGF-ß were significantly lower, and IL-10 and IL-6 were significantly higher in patients versus controls, underlying the complex interplay between genetic background and disease features.

Drug Design and Development for Rare Hematologic Diseases.

The last decade has seen an exponential increase in therapeutic options for rare hematologic diseases [...].

Non-capsulated Neisseria meningitidis sepsis in a paroxysmal nocturnal hemoglobinuria patient treated with ravulizumab: case report and review of the literature.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired haematopoietic stem cell disease characterized by complement-mediated intravascular hemolysis, thrombosis, and bone marrow failure. Eculizumab and ravulizumab are anti-C5 monoclonal antibodies that reduce hemolysis, anaemia and thrombotic risk, but are associated with increased risk of infection with encapsulated bacteria, including Neisseria meningitidis. We report a case of life-threatening infection by non-groupable Neisseria meningitidis in a young PNH patient treated with ravulizumab. Despite prompt admission to the intensive care unit, microbe isolation was delayed due to the negativity of capsular antigens, and the patient required intubation, dialysis, and transfusion support for pancytopenia. Notably, PNH disease activity remained controlled and no additional anti-C5 doses were administered. Increasing awareness regarding septic risk in PNH patients on complement inhibitors despite vaccinations is pivotal. A warning about serotypes generally not pathogenetic and not covered by vaccination, such as non-capsulated forms, is emerging.

Antibody based therapeutics for autoimmune hemolytic anemia.

INTRODUCTION: Autoimmune hemolytic anemia (AIHA) treatment has been revolutionized by the introduction of target therapies, mainly monoclonal antibodies (MoAbs). AREAS COVERED: The anti-CD20 rituximab, which targets Ab production by B-cells, induces 80% of response in warm-type AIHA (wAIHA) and 50-60% in cold agglutinin disease (CAD). Other B-cell targeting MoAbs including ianalumab, povetacicept, and obexelimab are under active study. The anti-CD38 MoAb daratumumab has been used in several reports to target long-lived plasma-cells responsible for AIHA relapse, being effective even in multi-refractory cases. Anti-complement MoAbs will soon change the treatment paradigm in CAD; the anti-C1s sutimlimab rapidly increased Hb in more than 80% of the cases. Finally, MoAbs inhibiting the neonatal Fc receptor (FcRn), such as nipocalimab, can reduce the half-life of the pathogenic autoAbs, representing a promising treatment for wAIHA. EXPERT OPINION: MoAbs offer the potential to improve efficacy by reducing toxicity. However, there is a huge need for clinical trials exploring response duration rather than short-term efficacy. Complement inhibitors and anti-FcRns do not abrogate autoAb production and are being developed as long-term therapies. Thus, the combination of B-cell/plasma cell targeting drugs deserves to be explored. On the other hand, their rapid efficacy should be exploited for the acute AIHA phase.

Severe autoimmune hemolytic anemia; epidemiology, clinical management, outcomes and knowledge gaps.

Autoimmune hemolytic anemia (AIHA) is an acquired hemolytic disorder, mediated by auto-antibodies, and has a variable clinical course ranging from fully compensated low grade hemolysis to severe life-threatening cases. The rarity, heterogeneity and incomplete understanding of severe AIHA complicate the recognition and management of severe cases. In this review, we describe how severe AIHA can be defined and what is currently known of the severity and outcome of AIHA. There are no validated predictors for severe clinical course, but certain risk factors for poor outcomes (hospitalisation, transfusion need and mortality) can aid in recognizing severe cases. Some serological subtypes of AIHA (warm AIHA with complement positive DAT, mixed, atypical) are associated with lower hemoglobin levels, higher transfusion need and mortality. Currently, there is no evidence-based therapeutic approach for severe AIHA. We provide a general approach for the management of severe AIHA patients, incorporating monitoring, supportive measures and therapeutic options based on expert opinion. In cases where steroids fail, there is a lack of rapidly effective therapeutic options. In this era, numerous novel therapies are emerging for AIHA, including novel complement inhibitors, such as sutimlimab. Their potential in severe AIHA is discussed. Future research efforts are needed to gain a clearer picture of severe AIHA and develop prediction models for severe disease course. It is crucial to incorporate not only clinical characteristics but also biomarkers that are associated with pathophysiological differences and severity, to enhance the accuracy of prediction models and facilitate the selection of the optimal therapeutic approach. Future clinical trials should prioritize the inclusion of severe AIHA patients, particularly in the quest for rapidly acting novel agents.

Deciphering treatment patterns in non-severe/moderate aplastic anemia: an international observational study.

Non-severe aplastic anemia is a rare bone marrow failure disorder characterized by variable degrees and combination of cytopenias, with limited data on management and outcome. We describe a large multicentric series of 259 patients, focusing on clinical and molecular features, treatment, evolution, and survival. The majority required treatment with cyclosporine (CyA) alone (N = 84) or in combination with anti-thymocyte globulin (ATG,44) or eltrombopag (20), eltrombopag alone (10), or others (25) including androgens. Similar outcomes were observed across different strategies, with a 6-month overall response rate of 73% for CyA, 74% for ATG plus CyA, 68% for CyA plus eltrombopag, 87% for eltrombopag, and 79% for others. Notably, 56 patients (39%), mainly receiving CyA plus eltrombopag, achieved a trilineage response (p = 0.02). Progression to myeloid neoplasms was limited (8%) and not related to mutational status. Hemolytic PNH developed in 10% of cases, being predicted by detection of small clones at diagnosis. Survival was negatively impacted by age, male gender, LDH, platelets/erythrocyte transfusion need, and somatic mutations by NGS, and positively by higher neutrophils at diagnosis, PNH clones, and trilineage response at 6 and 12 months. Multivariable analysis confirmed the detrimental role of age and the favorable association with PNH clone and trilineage response at 6 months.

Androgen use in bone marrow failures and myeloid neoplasms: Mechanisms of action and a systematic review of clinical data.

Despite recent advancements, treatment of cytopenia due to bone marrow failures (BMF) and myeloid neoplasms remains challenging. Androgens promote renewal and maturation of blood cells and may be beneficial in these forms. Here we report a systematic review of androgens use as single agent in hematologic conditions. Forty-six studies, mainly retrospective with various androgen types and doses, were included: 12 on acquired aplastic anemia (AA), 11 on inherited BMF, 17 on myelodysplastic syndromes (MDS), and 7 on myelofibrosis. Responses ranged from 50 to 70% in inherited BMF, 40-50% in acquired AA and MDS, while very limited evidence emerged for myelofibrosis. In acquired AA, response was associated with presence of non-severe disease; in MDS androgens were more effective on thrombocytopenia or mild to moderate anemia, whilst limited benefit was observed for transfusion dependent anemia. Toxicity profile mainly consisted of virilization and liver enzyme elevation, whilst the risk of leukemic evolution remains controversial.