Immune Thrombotic Thrombocytopenic Purpura: Pathophysiology, Diagnosis, Therapy and Open Issues.

Immune thrombotic thrombocytopenic purpura (iTTP) is a life-threatening thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury due to microvascular platelet-rich thrombi. iTTP pathophysiology is based on a severe ADAMTS13 deficiency, the specific von Willebrand factor (vWF)-cleaving protease, due to anti-ADAMTS13 autoantibodies. Early diagnosis and treatment reduce the mortality. Frontline therapy includes daily plasma exchange (PEX) with fresh frozen plasma replacement and immunosuppression with corticosteroids. Caplacizumab has recently been added to frontline therapy. Caplacizumab is a nanobody that binds to the A1 domain of vWF, blocking the interaction of ultra-large vWF multimers with the platelet and thereby preventing the formation of platelet-rich thrombi. Caplacizumab reduces mortality due to ischemic events, refractoriness, and exacerbations after PEX discontinuation. Until now, the criteria for response to treatment mainly took into account the normalization of platelet count and discontinuation of PEX; with the use of caplacizumab leading to rapid normalization of platelet count, it has been necessary to redefine the response criteria, taking into account also the underlying autoimmune disease. Monitoring of ADAMTS13 activity is important to identify cases with a low value of activity (<10IU/L), requiring the optimization of immunosuppressive therapy with the addition of Rituximab. Rituximab is effective in patients with refractory disease or relapsing disease. Currently, the use of Rituximab has expanded, both in frontline treatment and during follow-up, as a pre-emptive approach. Some patients do not achieve ADAMTS13 remission following the acute phase despite steroids and rituximab treatment, requiring an individualized immunosuppressive approach to prevent clinical relapse. In iTTP, there is an increased risk of venous thrombotic events (VTEs) as well as arterial thrombotic events, and most occur after platelet normalization. Until now, there has been no consensus on the use of pharmacological thromboprophylaxis in patients on caplacizumab because the drug is known to increase bleeding risk.

True vs. false immune-mediated thrombotic thrombocytopenic purpura exacerbations: a clinical case in the caplacizumab era.

Acquired thrombotic thrombocytopenic purpura (aTTP) is a medical emergency requiring urgent plasma exchange and immunosuppressive agents. Recently, the therapeutic options have been expanded by the approval of a novel anti-von Willebrand factor (vWF) nanobody, caplacizumab, inhibiting vWF-platelet aggregation. Here, we present a rare case of a patient affected by immune-mediated TTP (iTTP) reporting ischemic stroke caused by a real iTTP exacerbation during caplacizumab administration and subsequent pancytopenia caused by cytomegalovirus (CMV) infection that mimicked another iTTP exacerbation. The case is a real-life example of a not-frequent iTTP exacerbation in the caplacizumab era and of the new management issues arising with the introduction of the new drugs in clinical practice, highlighting the need of new comprehensive response criteria and treatment guidelines.

Caplacizumab use for immune thrombotic thrombocytopenic purpura: the Milan thrombotic thrombocytopenic purpura registry.

•Data on caplacizumab use for thrombotic thrombocytopenic purpura (TTP) in Italy are missing.•Twenty-six Italian patients were treated with caplacizumab for an acute immune TTP episode.•Caplacizumab was effective in treating acute TTP in the Italian real-world clinical setting.•Two major bleeds leading to drug discontinuation were observed.

Benefits and Safety of Empiric Antibiotic Treatment Active Against KPC-K. pneumoniae in Febrile Neutropenic Patients with Acute Leukemia Who are Colonized with KPC-K. pneumoniae. A 7-Years Retrospective Observational Cohort Study.

Purpose: To evaluate the benefits and safety of the empiric antibiotic treatment (EAT) active against KPC-K. pneumoniae in febrile neutropenic patients with acute leukaemia (AL) who are colonised by KPC-K. pneumoniae. Patients and Methods: A 7-year (2013-2019) retrospective observational cohort study was conducted at the Haematology, Sapienza Rome University (Italy) on 94 febrile neutropenia episodes (FNE) in AL patients KPC-K. pneumoniae carriers treated with active EAT. Results: Eighty-two (87%) FNE were empirically treated with antibiotic combinations [38 colistin-based and 44 ceftazidime-avibactam (CAZAVI)-based], 12 with CAZAVI monotherapy. Successful outcomes were observed in 88/94 (94%) FNE, 46/49 (94%) microbiologically documented infections, and 24/27 (89%) gram-negative bloodstream infections (GNB-BSI). Mortality due to infective causes was 4.2% (2.1% within 1 week). KPC-K. pneumoniae infections caused 28/94 FNE (30%) and KPC-K. pneumoniae-BSI was documented in 22 FNE (23.4%) (85% of GNB-BSI), in all cases patients received active EAT, and 21 survived. KPC-K.pneumoniae-BSI mortality rate was 4.5%. CAZAVI-based EAT showed better results than colistin-based EAT (55/56 vs 33/38, p = 0.037), overall and without EAT modification (41/56 vs 20/38, p = 0.02). Empirical combinations including CAZAVI were successful in 98% of cases (43/44 vs 33/38 for colistin-based EAT, p = 0.01), without modifications in 82% (36/44 vs 20/28, p = 0.02). All deaths occurred in patients treated with colistin-based EAT (4/38 vs 0/56, p = 0.02). CAZAVI-containing EAT was the only independent factor for an overall successful response (HR 0.058, CI 0.013-1.072, p = 0.058). Nephrotoxicity occurred in 3(8%) patients undergoing colistin-based EAT (none in those undergoing CAZAVI-based EAT, p = 0.02). Conclusion: KPC-K. pneumoniae infections are frequent in colonised AL patients with FNE. EAT with active antibiotics, mainly CAZAVI-based combinations, was effective, safe, and associated with low overall and KPC-K. pneumoniae-BSI-related mortality.

Impact of gemtuzumab ozogamicin consolidation on hematopoietic stem cells (HSCs) mobilization in AML: analysis of 20 patients.

Gemtuzumab ozogamicin (GO), is an anti-CD33 monoclonal antibody, approved for AML CD33 + , those patients with low and intermediate-risk who obtain a complete response may also be candidated for consolidation with autologous stem cell transplantation (ASCT). However, there are scant data on the mobilization of hemopoietic stem cells (HSC) after fractionated GO. We retrospectively studied data from five Italian centers and identified 20 patients (median age 54 years, range 29-69, 15 female, 15 NPM1mutated) that attempted HSC mobilization after fractionated doses of GO + "7 + 3" regimen and 1-2 cycles of consolidation (GO + HDAC + daunorubicin). After chemotherapy and standard G-CSF, 11/20 patients (55%) reached the threshold of 20 CD34 + /µL, and HSC were successfully harvested, while 9 patients (45%) failed. The median day of apheresis was Day + 26 from the start of chemotherapy (range 22-39 days). In good mobilizer patients, the median circulating CD34 + cells were 35.9 cells/µL and the median CD34 + harvested were 4.65 × 106/kg of patients' body weight. With a median follow-up of 12.7 months, at 24 months from the first diagnosis, 93.3% of all 20 patients were alive and the median overall survival was 25 months. The 2-year RFS rate from the timepoint of the first CR was 72.6%, while the median RFS was not reached. However, only five patients underwent ASCT and achieved full engraftment.In conclusion, in our cohort of patients, the addition of GO reduced HSC mobilization and harvesting, which was reached in about 55% of patients. Nevertheless, further studies are warranted to evaluate the effects of fractionated doses of GO on HSC mobilization and ASCT outcomes.

Fatigue in newly diagnosed acute myeloid leukaemia: general population comparison and predictive factors.

OBJECTIVES: This study compared the burden of fatigue between treatment-naïve patients with newly diagnosed acute myeloid leukaemia (AML) and the general population and investigated patient factors associated with fatigue severity. METHODS: Pretreatment patient-reported fatigue was assessed with the Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire in a sample of 463 newly diagnosed patients with AML who were enrolled in a clinical trial. Multivariable linear regression models were used to estimate the adjusted mean differences in fatigue between patients with AML and adults from the general population (n=847) by AML disease risk categories. A clinically meaningful difference in fatigue was defined as ≥3 points. Univariable and multivariable linear regression models were used to identify sociodemographic, clinical and molecular correlates of worse fatigue in patients with AML. RESULTS: Patients with AML reported adjusted mean fatigue scores that were 7.5 points worse than the general population (95% CI -8.6 to -6.4, p<0.001). Across AML disease risk categories, adjusted mean differences in fatigue compared with the general population ranged from 6.7 points worse (patients with favourable risk: 95% CI -8.6 to -4.8, p<0.001) to 8.9 points worse (patients with poor risk, 95% CI -10.5 to -7.2, p<0.001). Overall, 91% of patients with AML reported fatigue that was equal to or worse than the general population's median fatigue score. Higher pretreatment fatigue was independently associated with female sex, WHO performance status ≥1 and lower platelet levels. CONCLUSIONS: Patients with newly diagnosed AML reported worse fatigue than the general population, and mean differences exceeded twice the threshold for clinical significance. Our findings may help to identify patients with AML most likely to benefit from supportive care interventions to reduce fatigue.

Autologous stem cell transplantation (ASCT) for acute myeloid leukemia in patients in first complete remission after one versus two induction courses: A study from the ALWP of the EBMT.

BACKGROUND: Achieving complete remission (CR) is the main goal in AML treatment and a prerequisite for successful autologous stem cell transplantation (ACT). METHODS: Comparing results of peripheral blood ACT in patients with AML in CR1 attained following 1 versus 2 chemotherapy courses transplanted in 2000-2019. RESULTS: Patients 1532 (84%) with one and 293 (16%) patients with two induction chemotherapies courses (a total of 1825 patients) were included in the study. Follow-up was 7.9 (95% CI: 7.4-8.4) and 7.7 (95% CI: 7.0-8.6) years (p = 0.8). Time from diagnosis to ACT was 4.7 (range, 3.9-5.8) versus 5.7 (range, 4.7-7.1) months (p < 0.001), respectively. Leukemia free survival (LFS) and overall survival (OS) at 5 years were inferior for patients achieving CR1 with 2 versus 1 course of chemotherapy: 26.6% versus 41.7% (HR = 1.42 [95% CI: 1.22-1.66], p < 0.001) and 36.2% versus 53.3%, (HR = 1.48 [95% CI: 1.25-1.75], p < 0.001), and 5-year relapse incidence (RI) was higher: 67.2% versus 52.3%, (HR = 1.46 [95% CI: 1.25-1.72], p < 0.001). Five-year non-relapse mortality (NRM) was 6.2% versus 6.0% for patients with 2 versus 1 chemotherapy courses, and did not differ significantly (HR = 1.31 [95% CI: 0.81-2.10], p = 0.27). CONCLUSIONS: LFS and OS were inferior and relapse rate was higher in AML patients who received two inductions chemotherapy courses to reach CR1 before being autografted. AML patients who required 2 induction courses to achieve remission, may be offered allogeneic transplantation rather than an autologous one in an attempt to reduce their high RI and improve outcomes.

Immunogenicity of SARS-CoV-2 vaccination in patients undergoing autologous stem cell transplantation. A multicentric experience.

COVID-19 disease has a strong impact on hematological patients; those receiving autologous hematopoietic stem cell transplantation (aHSCT) represent a particularly vulnerable group, in which the effectiveness of vaccination is very variable. Chiarucci et al. showed that patients affected by non-Hodgkin lymphoma (NHL) and treated with rituximab experienced a lower rate of immunization against SARS-CoV-2 (54%), as well as significantly lower IgG antibody titers. In our multicenter retrospective observational study, we included 82 patients who underwent aHSCT, divided into two groups: 58 patients vaccinated after aHSCT (group A) and 24 vaccinated before getting transplantation (group B). In group A, 39 (67%) patients had positive serology, and the rate of positivity increased with time after aHSCT. In the subgroup of patients with NHL, the administration of rituximab predicted negative serology, particularly when administered in the 6 months before vaccination (13% response rate). Patients affected by plasma cells had a higher rate of positivity (83% overall), independently of the time to aHSCT. In group B, no patient who initially showed positive serology became negative after transplantation, so the aHSCT did not affect the response to the vaccination. Our study confirmed the role of rituximab as a negative predictor of response to SARS-CoV-2 vaccination, whereas the conditioning and transplantation procedure itself seemed to be less important.

Autologous stem cell transplantation in favorable-risk acute myeloid leukemia: single-center experience and current challenges.

BACKGROUND: Autologous stem cell transplantation (ASCT) has gained growing consideration as a treatment option for favorable-risk acute myeloid leukemia (FR-AML) in first complete remission (CR1), compared with chemotherapy. MATERIALS AND METHODS: We report the long-term outcomes of 117 consecutive patients with FR-AML fit for intensive chemotherapy diagnosed in our center between 1999 and 2020, who underwent ASCT. RESULTS: Sixty-five of the 117 were eligible for intensive post-remission treatment, and 42 of those 65 received ASCT. Median follow up was 132 months. Overall survival (OS) and disease-free survival (DFS) were 75% and 76%. Higher doses of CD34 + stem cell infusions negatively impacted DFS in multivariate analysis. Core-binding factor (CBF) leukemia was an independent prognostic factor for improved DFS. No differences based on pre-transplant measurable residual disease (MRD) were observed. In CBF leukemia, 10-year DFS is 72% for MRD-positive patients versus 100% for MRD negative patients. CONCLUSIONS: ASCT is effective and safe in FR-AML patients. In CBF leukemia, ASCT provides excellent results regardless of achievement of bone marrow MRD negativity. In NPM1-mutated/FLT3-wild type (mNPM1) AML, early molecular response seems to have more impact on prognosis. Prospective investigation of the role of gemtuzumab ozogamicin in this setting is ongoing.

Myeloid Sarcoma: Diagnostic and Treatment Tools from a Monocentric Retrospective Experience.

Myeloid sarcoma (MS) is a very rare disease in both adults and children. Prognosis is poor in adults; in the pediatric age, the prognostic impact of extramedullary disease is controversial. Systemic therapy represents the mainstay of treatment even in isolated MS, but a comparison between different induction regimens is very limited in the literature. To date, it is still not clear if induction treatment should differ from that of other acute myeloid leukemias and stem cell transplant is considered for consolidation in both leukemic patients and in those with isolated disease. Our study describes a retrospective series of 13 cases of MS (adults and children), diagnosed and treated at our institute over 18 years. We report the results of immunophenotypic, cytogenetic and molecular studies, therapeutic approaches, and outcome, in order to establish the best strategy for patients' workup.

Reduced mortality from KPC-K.pneumoniae bloodstream infection in high-risk patients with hematological malignancies colonized by KPC-K.pneumoniae.

BACKGROUND: KPC-K.pneumoniae bloodstream infection (KPC-KpBSI) mortality rate in patients with hematological malignancies is reported about 60%. The initial treatment active against KPC-K.pneumoniae is crucial for survival and KPC-K.pneumoniae rectal colonization usually precedes KPC-KpBSI. We evaluated the impact on KPC-KpBSI mortality of the preemptive use of antibiotics active against KPC-K.pneumoniae, as opposed to inactive or standard empiric antibiotics, for the empiric treatment of febrile neutropenia episodes in patients with hematological malignancy identified as KPC-K.pneumoniae intestinal carriers. METHODS: We compared the outcomes of KPC-KpBSIs occurring in high-risk hematological patients known to be colonized with KPC-K.pneumoniae, during two time periods: March2012-December2013 (Period 1, initial approach to KPC-K.pneumoniae spread) and January2017-October2018 (Period 2, full application of the preemptive strategy). The relative importance of the various prognostic factors that could influence death rates were assessed by forward stepwise logistic regression models. RESULTS: KPC-KpBSI-related mortality in hematological patients identified as KPC-K.pneumoniae carriers dropped from 50% in Period 1 to 6% in Period 2 (p < 0.01), from 58 to 9% in acute myeloid leukemia carriers(p < 0.01). KPC-KpBSIs developed in patients identified as KPC-K.pneumoniae carriers were initially treated with active therapy in 56% and 100% of cases in Period 1 and Period 2, respectively (p < 0.01), in particular with an active antibiotic combination in 39 and 94% of cases, respectively(p < 0.01). The 61% of KPC-KpBSI observed in Period 1 developed during inactive systemic antibiotic treatment (none in Period 2, p < 0.01), fatal in the 73% of cases. Overall, KPC-KpBSI-related mortality was 88% with no initial active treatment, 11.5% with at least one initial active antibiotic (p < 0.01), 9% with initial active combination. Only the initial active treatment resulted independently associated with survival. CONCLUSIONS: In high-risk hematological patients colonized by KPC-K.pneumoniae, the empiric treatment of febrile neutropenia active against KPC-K.pneumoniae reduced KPC-KpBSI-related mortality to 6% and prevented fatal KPC-KpBSI occurrence during inactive systemic antibiotic treatment.

The HLA Variant rs6903608 Is Associated with Disease Onset and Relapse of Immune-Mediated Thrombotic Thrombocytopenic Purpura in Caucasians.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening thrombotic microangiopathy caused by severe ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs 13) deficiency, recurring in 30-50% of patients. The common human leukocyte antigen (HLA) variant rs6903608 was found to be associated with prevalent iTTP, but whether this variant is associated with disease relapse is unknown. To estimate the impact of rs6903608 on iTTP onset and relapse, we performed a case-control and cohort study in 161 Italian patients with a first iTTP episode between 2002 and 2018, and in 456 Italian controls. Variation in rs6903608 was strongly associated with iTTP onset (homozygotes odds ratio (OR) 4.68 (95% confidence interval (CI) 2.67 to 8.23); heterozygotes OR 1.64 (95%CI 0.95 to 2.83)), which occurred over three years earlier for each extra risk allele (ß -3.34, 95%CI -6.69 to 0.02). Of 153 survivors (median follow-up 4.9 years (95%CI 3.7 to 6.1)), 44 (29%) relapsed. The risk allele homozygotes had a 46% (95%CI 36 to 57%) absolute risk of relapse by year 6, which was significantly higher than both heterozygotes (22% (95%CI 16 to 29%)) and reference allele homozygotes (30% (95%CI 23 to 39%)). In conclusion, HLA variant rs6903608 is a risk factor for both iTTP onset and relapse. This newly identified biomarker may help with recognizing patients at high risk of relapse, who would benefit from close monitoring or intensified immunosuppressive therapy.

A review of current induction strategies and emerging prognostic factors in the management of children and adolescents with acute lymphoblastic leukemia.

INTRODUCTION: Acute lymphoblastic leukemia is the most frequent hematologic malignancy in children. Almost 95% of children potentially achieve a complete remission after the induction treatment, but over the last years, new insights in the genomic disease profile and in minimal residual disease detection techniques have led to an improvement in the prognostic stratification, identifying selected patients' subgroups with peculiar therapeutic needs. AREAS COVERED: According to a comprehensive search of peer-review literature performed in Pubmed, in this review we summarize the recent evidences on the induction treatment strategies comprised in the children acute lymphoblastic leukemia scenario, focusing on the role of key drugs such as corticosteroids and asparaginase and discussing the crucial significance of the genomic characterization at baseline which may drive the proper induction treatment choice. EXPERT OPINION: Current induction strategies already produce durable remissions in a significant proportion of standard-risk children with acute lymphoblastic leukemia. A broader knowledge of the biologic features related to acute lymphoblastic leukemia subtypes with worse prognosis, and an optimization of targeted drugs now available, might lead to the achievement of long-term molecular remissions in this setting.

Prevalence of the age-related diseases in older patients with acquired thrombotic thrombocytopenic purpura.

BACKGROUND: The prevalence of older patients with acquired thrombotic thrombocytopenic purpura (TTP) is increasing. There is scarce information on the prevalence of multimorbidity, polypharmacy and age-related diseases in aging TTP patients. This study aimed to evaluate the prevalence of multimorbidity and polypharmacy in a population of acquired TTP patients aged 65 years or more compared with a group of age-matched controls. METHODS: Acquired TTP patients enrolled in the Milan TTP registry from December 1st 1999 to March 31th 2018 and aged 65 years or more at the date of last follow-up were evaluated. Controls were Italian healthy individuals recruited from 2006 to March 31th 2018 among friends and non-consanguineous relatives of patients tested for thrombophilia screening at the Angelo Bianchi Bonomi Hemophilia and Thrombosis Center of Milan. RESULTS: 36 TTP patients and 127 age-matched controls were included. Compared with controls, TTP patients had a higher prevalence of multimorbidity and polypharmacy. They also showed a higher prevalence of autoimmune diseases, osteoporosis and arterial hypertension and were more chronically treated with corticosteroids and antiplatelets for primary cardiovascular prevention. All these results were confirmed after adjusting for sex. Compared with the general elderly population, TTP patients showed a higher prevalence of ischemic heart disease and stroke. CONCLUSIONS: Our findings suggest that a careful comprehensive geriatric assessment of acquired TTP patients is necessary. It is important to look for other autoimmune diseases and such age-related comorbidities as osteoporosis, arterial hypertension, ischemic heart disease and cerebrovascular disease.