Efficacy of Recombinant Human Thrombopoietin for the Treatment of Secondary Failure of Platelet Recovery After Allogeneic HSCT

Secondary failure of platelet recovery (SFPR) is a life-threatening complication that may affect up to 20% of patients after allogeneic hematopoietic stem cell transplantation (HSCT). In this study, to evaluate the efficacy of recombinant human thrombopoietin (rhTPO), we retrospectively analyzed 29 patients who received continuous rhTPO for the treatment of SFPR. Overall response and complete response were observed in 24 (82.8%) patients and 10 (34.5%) patients, at a median time of 21.5 days (range, 3-41 days) and 39.5 days (range, 7-53 days) after initiation of rhTPO treatment, respectively. Among the responders, the probability of keeping overall response and complete response at 1 year after response was 77.3% and 80.0%, respectively. In multivariate analysis, higher CD34+ cells (≥3 × 106/kg) infused during HSCT (HR: 7.22, 95% CI: 1.53-34.04, P = 0.01) and decreased ferritin after rhTPO treatment (HR: 6.16, 95% CI: 1.18-32.15, P = 0.03) were indicated to associate with complete response to rhTPO. Importantly, rhTPO was well tolerated in all patients without side effects urging withdrawal and clinical intervention. The results of this study suggest that rhTPO may be a safe and effective treatment for SFPR.

Safety and immunogenicity of BNT162b2 mRNA COVID-19 vaccine in Japanese patients after allogeneic stem cell transplantation.

Patients who have undergone hematopoietic stem cell transplantation (HSCT) for hematological disease experience high mortality when infected by coronavirus disease 2019 (COVID-19). However, the safety and efficacy of COVID-19 vaccine in HSCT patients remains to be investigated. We prospectively evaluated the safety and immunogenicity of BNT162b2 mRNA COVID-19 vaccine (Pfizer BioNTech) in 25 Japanese allogeneic HSCT patients in comparison with 19 healthy volunteers. While anti-S1 antibody titers in almost all healthy volunteers after the second dose were higher than the cut-off value reported previously, levels in HSCT patients after the second dose were diverse. Nineteen patients (76%) got seroconversion of anti-S1 IgG. Median optical density of antibody levels in HSCT patients with low IgG levels (< 600 mg/dL), steroid treatment, or low lymphocytes (< 1000 /μL) was significantly lower than that in the other HSCT patients. There were no serious adverse events (> Grade 3), no new development or exacerbation of graft-versus-host disease after vaccination. We concluded BNT162b2 mRNA vaccine is safe and effective in Japanese allogeneic HSCT patients.

Oral Mucositis Association with Periodontal Status: A Retrospective Analysis of 496 Patients Undergoing Hematopoietic Stem Cell Transplantation

Background: Hematopoietic stem cell transplantation (HSCT) can induce serious oral complications, including oral mucositis (OM). The presence of periodontal inflammation before HSCT is believed to be associated with OM. The aim of our study was to determine the prevalence and severity of OM in patients undergoing HSCT and its relation to periodontal status. Patients and methods: This is a retrospective study of patients who underwent HSCT and a detailed dental examination between 2007 and 2015. The dental and periodontal status of all patients was evaluated by clinical and radiographic examination prior to HSCT. Oral health was assessed with the gingival index, the the community periodontal index, presence of plaque-related gingivitis, and marginal periodontitis. During the HSCT period, patients were examined daily for the presence of OM, which was graded according to World Health Organization (WHO) classification if present. The patients were assigned to the groups according to type of transplantation: autologous HSCT, myeloablative allogeneic HSCT, and non-myeloablative allogeneic HSCT. Results: A total of 496 patients were included in the study. OM was present in 314 of 496 patients (63.3%): 184/251 (73.3%) in the autologous group, 100/151 (66.2%) in the myeloablative allogeneic group, and 30/94 (31.9%) in the nonmyeloablative allogeneic group. Significantly more patients suffered from OM in the autologous and myeloablative groups versus the nonmyeloablative conditioning group (p < 0.001). The presence of periodontal inflammation did not significantly differ among the groups. There was only a borderline trend for the higher prevalence of OM in the non-myeloablative allogeneic nonmyeloablative group when periodontal inflammation was present (0.073939). Conclusions: Oral mucositis prevalence and severity after stem cell transplantation is not widely affected by the oral hygiene and periodontal disease presence before HSCT. We confirmed the wide-known connection of the conditioning regimen intensity to the prevalence of OM.

Myelodysplastic syndromes (MDS)

MDS in children is a rare group of hematopoietic stem cell clonal disorder. Allogeneic HSCT is the only curative treatment. HLA typing and the search for a compatible donor must be carried out upon diagnosis, for all patients. However, patients with refractory cytopenia of childhood without an unfavorable karyotype can keep the disease stable for a long time. Thus, in the absence of transfusion dependence or severe neutropenia, a careful observation strategy without treatment is recommended. The treatment of children diagnosed with MDS with excess blasts remains a major challenge. Allogeneic HSCT is the only curative treatment, although the data published in the literature generally include a small number of patients, heterogeneously transplanted. For children with MDS secondary to therapy, despite HSCT, the evolution is generally unfavorable.

Common points of therapeutic intervention in COVID-19 and in allogeneic hematopoietic stem cell transplantation associated severe cytokine release syndrome

Allogeneic hematopoietic stem cell transplantation (HSCT) and coronavirus disease 2019 (COVID-19) infection can both lead to severe cytokine release syndrome (sCRS) resulting in critical illness and death. In this single institution, preliminary comparative case-series study we compared clinical and laboratory co-variates as well as response to tocilizumab (TCZ)-based therapy of 15 allogeneic-HSCT- and 17 COVID-19-associated sCRS patients. Reaction to a TCZ plus posttransplant cyclophosphamide (PTCY) consolidation therapy in the allogeneic-HSCT-associated sCRS group yielded significantly inferior long-term outcome as compared to TCZ-based therapy in the COVID-19-associated group (P = 0.003). We report that a TCZ followed by consolidation therapy with a Janus kinase/signal transducer and activator of transcription (JAK/STAT) inhibitor given to 4 out of 8 critically ill COVID-19 patients resulted in their complete recovery. Non-selective JAK/STAT inhibitors influencing the action of several cytokines exhibit a broader effect than TCZ alone in calming down sCRS. Serum levels of cytokines and chemokines show similar changes in allogeneic-HSCT- and COVID-19-associated sCRS with marked elevation of interleukin-6 (IL-6), regulated upon activation normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1) and interferon γ-induced protein 10 kDa (IP-10) levels. In addition, levels of IL-5, IL-10, IL-15 were also elevated in allogeneic-HSCT-associated sCRS. Our multi-cytokine expression data indicate that the pathophysiology of allogeneic-HSCT and COVID-19-associated sCRS are similar therefore the same clinical grading system and TCZ-based treatment approaches can be applied. TCZ with JAK/STAT inhibitor consolidation therapy might be highly effective in COVID-19 sCRS patients.

Risk Stratification, Measurable Residual Disease, and Outcomes of AML Patients with a Trisomy 8 Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Background: For most patients with acute myeloid leukemia (AML) harboring a trisomy 8 an allogeneic hematopoietic stem cell transplantation (HSCT) is a suitable and recommended consolidation therapy. However, comparative outcome analyses between patients with and without trisomy 8 undergoing allogeneic HSCT have not been performed so far. Methods: We retrospectively analyzed clinical features, outcomes, and measurable residual disease (MRD) of 659 AML (12%, n = 81, with a trisomy 8) patients subjected to allogeneic HSCT as a consolidation therapy. Results: The presence of a trisomy 8 associated with a trend for higher age at diagnosis, AML of secondary origin, lower white blood cell counts at diagnosis, worse ELN2017 genetic risk, wild-type NPM1, and mutated IDH1/2 and JAK2. Outcomes after allogeneic HSCT in the entire cohort did not differ between patients with a sole trisomy 8, trisomy 8 with additional cytogenetic aberrations or without a trisomy 8. A trisomy 8 did not affect outcomes within the three ELN2017 risk groups. In accordance with findings in unselected patient cohorts, persistent MRD at allogeneic HSCT in patients with a trisomy 8 identified individuals with a higher risk of relapse following allogeneic HSCT. Conclusions: Outcomes of trisomy 8 patients after allogeneic HSCT did not compare unfavorably to that of other AML patients following allogeneic HSCT. Rather than the presence or absence of a trisomy 8, additional genetic aberrations and MRD at HSCT define outcome differences and aid in informed treatment decisions.

Antibody Response to 2-Dose Sars-Cov-2 mRNA Vaccine in Allogeneic Hematopoietic Cell Transplant Recipients

INTRODUCTION Immunocompromised patients have been excluded from initial trials evaluating SARS-CoV-2 mRNA vaccines and there is a critical need to warrant vaccine efficacy in hematopoietic stem cell transplant (HSCT) recipients. In this study, we evaluated antibody responses to 2 doses mRNA SARS-CoV-2 vaccine in allogeneic HSCT recipients. METHODS We retrospectively enrolled successive hematopoietic cell transplant recipients across France who completed the 2-dose SARS-CoV-2 mRNA vaccine (BNT162b2 or mRNA-1273) between January 1 st and July 15 th 2021. All included patients had an available semi-quantitative antispike serologic testing after the second dose (from Roche, DiaSorin, Abbott or Siemens). We excluded patients with a prior COVID-19 confirmed by serology or PCR. For detectable antibody, we calculated the binding antibody units per milliliter (BAU/mL) according to the WHO International Standard by applying conversion factors given by the manufacturers (Kristiansen et al. , The Lancet 2021). Antibody response was categorized as "weak" or "good" with a threshold of 264 BAU/mL which has been associated to an estimate of 80% of mRNA vaccine-induced protection against symptomatic COVID-19 in immunocompetent patients (Feng S. et al., medRxiv 2021). We built a multivariate logistic regression model to assess factors independently associated with the absence of antibody response after the second dose of mRNA vaccination. RESULTS Overall, 620 allogeneic HSCT recipients from 12 hospitals across France were included in the analysis (60% male with a median age of 59 years old [IQR 47-66]), most with a myeloid (69%) or lymphoid (26%) malignancies. Donors were matched unrelated for 51%, HLA-identical sibling for 31% and haplo-identical for 18%. Thirty-one percent of HSCT recipients underwent a myeloablative conditioning, while 69% received a reduced intensity conditioning. The two doses of vaccines were given one month apart and the median time between transplantation and the initiation of vaccination was 29 months [IQR 14-58]. At a median of 33 [IQR 27-50] days after dose 2, an antibody response was detectable in 496 patients (80% [95CI: 77 to 83%]). Median [IQR] antibody levels was 243 BAU/mL [29.4-1391]. We classified detectable antibody responses as "weak" in 189 patients (30% [95CI 27 to 34%]) and as "good" in 306 (49% [95CI: 45 to 53%]). In the multivariate analysis including 533 patients (420 with detectable antibodies), factors associated with the absence of humoral responses were a time-interval from HSCT &lt; 12 months (ajusted Odds-Ratio (aOR) 2.8 [95CI 1.6 to 4.8]), absolute lymphocyte count &lt;1G/L (aOR 3.0 [95CI 1.7 to 5.0]), systemic immunosuppressive treatments within 3 months of vaccination (aOR 4.5 [95CI 2.7 to 7.5]), together with the use of rituximab within 6 months (aOR 15.1 [95CI 4.3 to 52.7]). In a subsequent multivariate analysis conducted a subset of 227 patients (170 with detectable antibodies) with available gammaglobulinemia as well as B and T lymphocytes counts, factors remaining associated with the absence of antibody response were only low B-lymphocytes count (aOR 5.5 [95CI 2.4 to 12.3]) and time-interval from HSCT &lt; 12 months (aOR 3.3 [95CI 1.5 to 7.2]). CONCLUSION After 2 dose mRNA vaccination, the majority of allogeneic HSCT recipients developed an antibody response although a significant proportion of these responses may be insufficient. Studies are still needed to investigate the effect of a third vaccine dose in patients with a null or weak humoral response. Disclosures Loschi: Servier: Ended employment in the past 24 months, Honoraria; Novartis: Ended employment in the past 24 months, Honoraria; Gilead: Ended employment in the past 24 months, Honoraria; AbbVie: Ended employment in the past 24 months, Honoraria; CELGENE/BMS: Honoraria; MSD: Honoraria.

Hematologic Recovery after Allogeneic Transplantation: Risk Factors and Its IMPACT on Transplant Related Mortality

Introduction. Hematologic recovery is often not satisfactory in patients undergoing an allogeneic stem cell transplantation (HSCT). A significant proportion have been reported to have low peripheral blood counts, despite full donor chimerism. This condition can be related to several factors including: number of CD34+ cells infused , stem cell source, underlying disease, conditioning regimen, GvHD and viral infections. Recently transplant platforms have changed, including the use of haploidentical transplants and modified GvHD prophylaxis. Aim of the study: to investigate factors associated with hematological recovery following an allogeneic HSCT in current transplant years. Methods: We included 1311 patients, with hematological diseases, undergoing an allogeneic HSCT, between year 2000 and 2020, in two transplant center: Genova and Roma. The main diagnoses were acute leukemia (54%), lymphoproliferative disorders (13%) , myelodysplastic syndromes (9%) and myelofibrosis (9%). 1108 patients aged &lt;60 years and 203 aged &gt;60 years. Platelet counts were taken as a surrogate marker of hematologic recovery. Results: We first ran a multiple regression analysis on factors influencing platelet counts between 50 and 100 days post-transplant. These factors were patients age &gt;60 years, GvHD grade II-IV, non sibling donor and a diagnosis of myelofibrosis. Platelet recovery at different time points, up to over 4 years post-transplant, is shown in Figure 1a in patients stratified according to an age cut off of 60 years. Patients younger than 60 years showed significantly improved platelet recovery , at each time point, when compared to patients over 60 years ; the difference persisted beyond 4 years. There was no difference in platelet recovery in patients aged 18-40 and 41-60. Donor age and year of transplant had no effect on platelet recovery. Figure 1b shows platelet recovery according to risk factors (age, GvHD, myelofibrosis, non sib donor). Transplant related mortality (TRM). We then asked whether low platelet counts predicted TRM. Patients with a platelets count higher than 20 and 50x10^9 on days 50-100 post-HSCT, showed a reduced transplant related mortality (TRM) as compared to patients with a lower platelet count (13%vs 39%: p&lt;0.000001; 11% vs31%, p&lt;0.000001) (Figure 1 c,d). Conclusions: Platelet recovery post-HSCT seems to be strongly influenced by patient's age, together with GvHD, a diagnosis of myelofibrosis and donor type. Slow recovery in older patients remains statistically significant beyond 4 years after HSCT. Hematologic recovery after HSCT has not improved over the past 2 decades. Low platelet counts are a strong risk factor for mortality after allogeneic HSCT. Clinical trials with TPO agonists post HSCT are warranted to assess whether hematologic recovery can be improved, and whether this will translate in reduced mortality. Figure 1 Figure 1. Disclosures Sica: Pfizer: Honoraria. Laurenti: AstraZeneca: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Roche: Honoraria, Research Funding; Gilead: Honoraria; BeiGene: Honoraria. Metafuni: Jazz: Other: Invited Clinical case presentation at meeting. Angelucci: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene BSM: Honoraria, Other: DMC; Blue Bird Bio: Honoraria, Membership on an entity's Board of Directors or advisory committees; Menarini-Stemline: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: steering commitee, Speakers Bureau; Vertex Pharmaceuticals: Honoraria, Other: DMC; Crispr therapeutics: Honoraria, Other: DMC; Glaxo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Serological Response Following BNT162b2 Anti-Sars-Cov-2 mRNA Vaccination in Hematopoietic Stem Cell Transplantation Patients

Patients with hematological malignancies (HM) undergoing hematopoietic stem cell transplantation (HSCT) have an increased vulnerability to SARS-Cov-2 (Sharma et al, Lancet Haematology 2020; Ljungman et al, Leukemia 2021), the reason why international guidelines strongly support the need for a protective vaccination for these subjects. The most relevant data currently available on the response to a complete anti-SARS-Cov-2 vaccination cycle in HM patients after HSCT refer to 314 patients reported in a Lithuanian national survey (Maneikis et al, Lancet Haematol 2021). In this study, the median titers of antibodies against SARS-Cov-2, determined 7-21 days after the second vaccination, were comparable to that of healthy controls (HC) in both autologous and allogeneic groups, with no patient found below the protective threshold of 50 arbitrary units (AU)/ml. Notably, the large majority of patients had received the transplant more than 1 year before vaccination. In a prospective, cohort study, we compared 114 patients, who had received an autologous or allogeneic HSCT at least three months before the first dose of vaccination, to 107 HC, matched for age and sex. Study population and HC received two doses of BNT162b2 anti-SARS-Cov-2 mRNA vaccine on days 1 and 21, between April and May 2021. Serological tests were performed by a commercially available immunoassay for the quantitative determination of anti-spike IgG antibodies to SARS-Cov-2. The cut-off for defining responders was 50 or greater AU/ml. Patients and HC samples were collected four weeks after the second dose of the vaccine. Table 1 reports the main clinical characteristics of patients and HC. Eighteen of 114 patients (16%) did not respond (24% in the allogeneic group, 6% in autologous recipients). Overall, median antibodies titers did not differ between HC and the entire cohort of transplanted patients, recipients of allogeneic HSCT, all patients responding to the vaccine or responders in the autologous subgroup (Figure 1A). All autologous HSCT recipients had significantly lower titers of antibodies than HC, while higher levels were found in responders who had received allogeneic HSCT (Figure 1A). Responders in the allogeneic subgroup showed antibodies titers significantly higher than responders in the autologous subgroup (Figure 1B). We further stratified patients in three groups, according to the time elapsed from transplant to vaccination: G1:&lt;1 year; G2:1-5 years; G3:&gt;5 years. Higher antibodies titers were observed in HC compared to all transplanted patients in G1 (Figure 1C), including both allogeneic (Figure 1D) and autologous (Figure 1E) HSCT recipients. No differences emerged in G2 between HC and all patients (Figure 1C), allogeneic (Figure 1D) or autologous (Figure 1E) HSCT recipients. Finally, no differences were found in G3 when comparing HC with all patients (Figure 1C) or allogeneic recipients (Figure 1D), whereas patients in the autologous subgroup showed significantly lower titers than HC (Figure 1E). Myeloma patients with controlled disease showed higher titers than patients with active disease (Figure 1F). According to median age, autologous HSCT recipients older than 57 years had significantly lower antibody levels than younger patients (Figure 1G). Autologous vs allogeneic HSCT, age of all patients and of allogeneic HSCT recipients, sex, type of allogeneic HSCT, conditioning regimen, age and sex of donor, occurrence of GVHD, disease type and single vs double autologous HSCT did not significantly impact on antibody levels (data not shown). No relevant side effects were recorded after vaccination. With a median follow up of 12 weeks, no case of COVID19 occurred among vaccinated patients. In our single center study, patients with a previous history of HSCT tolerated well BNT162b2 vaccine and mounted a potentially protective immune response in the majority of cases one month after two doses of vaccine. However, lack of response was not rare, especially in the allogeneic setting. The main factor associated with the quality of response was the time from HSCT, with lower responses within the first year from transplant and differences between autologous and allogeneic groups transplanted more than five years before vaccination. Here, a consolidated, complete immune reconstitution in allogeneic HSCT recipients, as well as age and a still active disease in the autologous setting, could have played opposite pivotal roles. Figure 1 Figure 1. Disclosures Delia: Gilead: Consultancy; Amgen: Consultancy; abbvie: Consultancy; Jazz pharmaceuticals: Consultancy.

Maintenance Therapy in Patients with FLT3-ITD-Mutation-Positive Acute Myeloid Leukemia after Allogeneic Hematopoietic Cell Transplantation: Real-World Survival

Background: Patients with FLT3-mutation-positive (FLT3mut+) acute myeloid leukemia (AML) have a poor prognosis, particularly those with a high allelic burden of FLT3-ITD mutations (FLT3-ITD mut+). Further, patients with FLT3-ITD mut+ who have relapsed after allogeneic hematopoietic stem cell transplantation (HSCT) have a 1-year overall survival (OS) rate of less than 20%. While treatment guidelines vary in their recommendations for maintenance therapy after HSCT to prevent relapse, data are emerging on the potential benefits of maintenance therapy for patients with FLT3mut+ AML. Aim/Objective: To examine real-world survival outcomes in adult patients with FLT3-ITD mut+ AML who received maintenance therapy versus those who did not receive maintenance therapy after allogeneic HSCT, including a qualitative comparison with real-world survival outcomes in adults with FLT3mut+ AML. Methods: This was a retrospective chart review wherein hematologists and oncologists from North America, Europe, and Japan extracted data from the medical charts of patients with FLT3mut+ AML who underwent HSCT after achieving complete remission with first-line chemotherapy within the prior 3 years. The index date was the date of HSCT and the study period was from the index date to the date of the last follow-up or death. All patients were grouped into two cohorts based on post-HSCT therapy received (no maintenance therapy or maintenance therapy). In an analysis of a subgroup of patients typically considered to be at high risk of relapse, patients who had both received an allogeneic HSCT and had a high allelic burden of FLT3-ITD mut+ were analyzed; patients with FLT3-ITD and FLT3-TKD co-mutations were also included in this subgroup. Overall survival during the study period was assessed for each cohort in the overall population of patients and in the subgroup. Kaplan-Meier analyses and Cox regression models, including unadjusted models and models with adjustments for baseline covariates, were used to describe and evaluate cross-cohort comparisons of survival. Covariates in the adjusted Cox models were Eastern Cooperative Oncology Group status, risk status, measurable residual disease status, age at index date, sex, extramedullary involvement, race, BMI, time from diagnosis to index month, HSCT type, and country. Results: A total of 1,208 AML patients with FLT3mut+ who received HSCT were included in the general study population; 765 (63.3%) patients received no maintenance therapy and 443 (36.7%) patients received maintenance therapy (including FLT3 inhibitors, hypomethylating agents, cytotoxic chemotherapy, and other targeted therapies). In Kaplan-Meier analyses, OS was longer in patients who received maintenance therapy compared with those who did not receive maintenance therapy (log-rank P&lt;0.001; Figure A). Similar results were seen between maintenance therapy versus no maintenance therapy in an unadjusted Cox regression model (HR 0.52 [95% CI 0.35, 0.76], P&lt;0.001) and adjusted Cox regression model (HR 0.48 [95% CI 0.30, 0.77], P&lt;0.01). In an analysis of the subgroup, data from the charts of 745 patients with FLT3-ITD mut+ who received allogeneic HSCT were reviewed. The mean age at HSCT was 53.2 years; 39.9% and 38.4% of patients had intermediate and poor risk status, respectively. Of this subgroup, 473 (63.5%) patients received no maintenance therapy and 272 (36.5%) patients received maintenance therapy. Kaplan-Meier analyses show that OS was longer in patients receiving maintenance therapy versus no maintenance therapy (log-rank P&lt;0.001; Figure B); the risk of death appeared to plateau after approximately 2 years in patients receiving maintenance treatments. Similar results were seen between maintenance therapy versus no maintenance therapy in an unadjusted Cox regression model (HR 0.39 [95% CI 0.23, 0.65], P&lt;0.001) and adjusted Cox regression model (HR 0.38 [95% CI 0.20, 0.72], P&lt;0.01). Conclusions: In patients with FLT3-ITD mut+ AML, OS was improved in patients that received any type of maintenance therapy compared with patients that received no maintenance therapy after allogeneic HSCT. These improved clinical outcomes in a high-risk subgroup receiving maintenance treatments are consistent with findings in the general population of patients with FLT3mut+ AML. Additional analyses are warranted to statistically verify these results. Figure 1 Figure 1. Disclosures Yang: Astellas Pharma, Inc.: Consultancy. Song: Astellas Pharma, Inc.: Consultancy. Griffin: Astellas Pharma, Inc.: Consultancy; Novartis: Patents & Royalties: Post marketing royalties from midostaurin. Shah: Astellas Pharma, Inc.: Current Employment; University of Michigan School of Public Health Department of Health Management and Policy Alumni Board: Other: Chair-Elect. Freimark: Astellas Pharma, Inc.: Consultancy. Chilelli: Astellas Pharma, Inc.: Current Employment.