Preclinical in vivo assessment of the activity of AZD7442 anti-SARS-CoV-2 monoclonal antibodies against Omicron sublineages.

Therapeutic monoclonal antibodies have been successful in protecting vulnerable populations against SARS-CoV-2. However, their effectiveness has been hampered by the emergence of new variants. To adapt the therapeutic landscape, health authorities have based their recommendations mostly on in vitro neutralization tests. However, these do not provide a reliable understanding of the changes in the dose-effect relationship and how they may translate into clinical efficacy. Taking the example of EvusheldTM (AZD7442), we aimed to investigate how in vivo data can provide critical quantitative results and project clinical effectiveness. We used the Golden Syrian hamster model to estimate 90 % effective concentrations (EC90) of AZD7442 in vivo against SARS-CoV-2 Omicron BA.1, BA.2 and BA.5 variants. While our in vivo results confirmed the partial loss of AZD7442 activity for BA.1 and BA.2, they showed a much greater loss of efficacy against BA.5 than that obtained in vitro. We analyzed in vivo EC90s in perspective with antibody levels measured in a cohort of immunocompromised patients who received 300 mg of AZD7442. We found that a substantial proportion of patients had serum levels of anti-SARS-CoV-2 spike protein IgG above the estimated in vivo EC90 for BA.1 and BA.2 (21 % and 92 % after 1 month, respectively), but not for BA.5. These findings suggest that AZD7442 is likely to retain clinical efficacy against BA.2 and BA.1, but not against BA.5. Overall, the present study illustrates the importance of complementing in vitro investigations by preclinical studies in animal models to help predict the efficacy of monoclonal antibodies in humans.

[Fertility preservation and hematopoietic stem cell transplantation (SFGM-TC)]. / Fertilité et greffe de cellules souches hématopoïétiques (SFGM-TC).

Conditioning regimen prior to hematopoietic stem cell transplantation have an impact on patient fertility through the use of gonadal irradiation and/or bifunctional alkylating agents. Their impact on fertility depends mainly on the dose used and, in women, on age at the time of treatment. All patients should benefit before treatment from a consultation informing them of the potential impact on fertility and of fertility preservation techniques. In the absence of contraindications, the major toxicity of myeloablative conditioning regimen justifies fertility preservation. There are few data concerning fertility after reduced-intensity conditioning. Despite lower theoretical gonadotoxicity, we also recommend fertility preservation, if possible before transplantation. The fertility preservation techniques used depend on the patient's age, pathology and conditioning. In the event of subsequent use of harvested gonadal tissue in the context of acute leukemia or aggressive lymphoma, it is advisable to assess the risk of reintroduction of tumor cells. Finally, it is recommended to assess gonadal function after transplant, especially after reduced conditioning. If there is persistent residual gonadal function, post-treatment fertility preservation should be discuss.

Late Relapse after Allogeneic Stem Cell Transplantation in Patients Treated for Acute Myeloid Leukemia: Relapse Incidence, Characteristics, Role of Conditioning Regimen, and Outcome.

Late relapse, beyond 2 years following alloHSCT for AML, is rare. Among the 376 patients allografted for AML in our center between 1990 and 2016, 142 (38%) relapsed. The majority (68%) of relapses occurred during the first year following transplantation. Beyond 2 years after alloHSCT, relapse was observed in 26 patients, representing 6.9% of the whole transplanted cohort and 18.3% of the relapsing patients. Cytogenetics at relapse was available in 21 patients and remained for 15 of them concordant to that at diagnosis. The majority (85.7%) of the patients were in CR prior to transplant. Thirteen patients had grade 1-2 acute GvHD, while 13 other patients had grade 3-4 acute GvHD. None of these patients subsequently developed chronic GvHD. In multivariate analyses, a predictive factor of the absence of relapse 2 years after transplantation was the development of extensive chronic GVHD. Salvage therapy achieved new CR in 77% of these patients. We conclude that late relapse can affect a significant minority of patients allografted for AML, and the intensity of the conditioning regimen does not seem to have an impact on these relapses. Moreover, we were able to show that those patients can receive effective salvage therapy.

Successful treatment of congenital erythropoietic porphyria using matched unrelated hematopoietic stem cell transplantation in an adult: A case report.

Congenital erythropoietic porphyria (CEP), or Gunther disease, is a rare genetic disease responsible for severe dermatologic, hepatic and/or haematological damages related to the deficient activity of the uroporphyrinogen III synthase. Allogeneic stem cell transplantation (Allo-SCT) represents the only curative treatment and few allotransplanted cases have been reported in children but not in adults. Here we report for the first time the successful cure of a 46-year old man with CEP with a 5-year follow-up after Allo-SCT.

Risk factors for Nocardia infection among allogeneic hematopoietic cell transplant recipients: A case-control study of the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation.

OBJECTIVES: Nocardiosis is a rare but life-threatening infection after hematopoietic cell transplantation (HCT). We aimed at identifying risk factors for nocardiosis after allogeneic HCT and clarifying the effect of trimethoprim-sulfamethoxazole prophylaxis on its occurrence. METHODS: We performed a retrospective multicenter case-control study of patients diagnosed with nocardiosis after allogeneic HCT between January 2000 and December 2018. For each case, two controls were matched by center, transplant date, and age group. Multivariable analysis was conducted using conditional logistic regression to identify potential risk factors for nocardiosis. Kaplan-Meier survival curves of cases and controls were compared using log-rank tests. RESULTS: Sixty-four cases and 128 controls were included. Nocardiosis occurred at a median of 9 months after allogeneic HCT (interquartile range: 5-18). After adjustment for potential confounders in a multivariable model, Nocardia infection was associated with tacrolimus use (adjusted odds ratio [aOR] 9.9, 95 % confidence interval [95 % CI]: 1.6-62.7), lymphocyte count < 500/µL (aOR 8.9, 95 % CI: 2.3-34.7), male sex (aOR 8.1, 95 % CI: 2.1-31.5), recent use of systemic corticosteroids (aOR 7.9, 95 % CI: 2.2-28.2), and recent CMV infection (aOR 4.3, 95 % CI: 1.2-15.9). Conversely, use of trimethoprim-sulfamethoxazole prophylaxis was associated with a significantly decreased risk of nocardiosis (aOR 0.2, 95 % CI: 0.1-0.8). HCT recipients who developed nocardiosis had a significantly decreased survival, as compared with controls (12-month survival: 58 % and 90 %, respectively; p < 0.0001). CONCLUSIONS: We identified six factors independently associated with the occurrence of nocardiosis among allogeneic HCT recipients. In particular, trimethoprim-sulfamethoxazole prophylaxis was found to protect against nocardiosis.

Phase I study of zoledronic acid combined with escalated doses of interleukine-2 for early in vivo generation of Vγ9Vδ2 T-cells after haploidentical stem cell transplant with posttransplant cyclophosphamide.

The presence of donor Vγ9Vδ2 T-cells after haploidentical hematopoietic stem cell transplant (h-HSCT) has been associated with improved disease-free survival. These cells kill tumor cells in a non-MHC restricted manner, do not induce graft-versus-host disease (GVHD), and can be generated by stimulation with zoledronic acid (ZA) in combination with interleukin-2 (IL-2). This monocentric phase I, open-label, dose-escalating study (ClinicalTrials.gov: NCT03862833) aimed at evaluating the safety and possibility to generate Vγ9Vδ2 T-cells early after h-HSCT. It applied a standard 3 + 3 protocol to determine the maximum tolerated dose (MTD) of increasing low-doses of IL-2 (5 days [d] per week, 4 weeks) in combination with a single dose of ZA, starting both the first Monday after d + 15 posttransplant. Vγ9Vδ2 T-cell monitoring was performed by multiparameter flow cytometry on blood samples and compared with a control cohort of h-HSCT recipients. Twenty-six patients were included between April 2019 and September 2022, 16 of whom being ultimately treated and seven being controls who received h-HSCT only. At the three dose levels tested, 1, 0, and 1 dose-limiting toxicities were observed. MTD was not reached. A significantly higher number of Vγ9Vδ2 T-cells was observed during IL-2 treatment compared with controls. In conclusion, early in vivo generation of Vγ9Vδ2 T-cells is feasible after h-HSCT by using a combination of ZA and repeated IL-2 infusions. This study paves the way to a future phase 2 study, with the hope to document lesser posttransplant relapse with this particular adaptive immunotherapy.

[Vaccination of allogeneic haematopoietic stem cell transplant recipients: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]. / Mise à jour du calendrier vaccinal après allogreffe de cellules souches hématopoïétiques : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC).

During immune reconstitution following allogeneic haematopoietic stem cell transplantation (allo-HSCT), (re)vaccination of allo-HSCT recipients is recommended. Herein, we propose an update of practical recommendations regarding vaccination of allo-HSCT recipients. These recommendations, based on data from the literature, national and international guidelines and the consensus of the participants when no formally proven data are available, were elaborated during the workshop of practice harmonization organized by the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) in Lille in September 2022.

Tocilizumab in combination with a standard induction chemotherapy in acute myeloid leukaemia patients (TOCILAM study): a single-centre, single-arm, phase 1 trial.

Background: In acute myeloid leukaemia (AML), interleukin-6 (IL-6) promotes chemo-resistance and its levels correlate with poor prognosis. IL-6 blockade may represent a promising therapeutic strategy. We aimed to test, tocilizumab, an anti-IL-6 receptor (R) monoclonal antibody in combination with standard intensive AML induction chemotherapy. Methods: This investigator-initiated single-centre phase 1 trial was conducted at Nantes University Hospital in France. According to a continual reassessment method, three escalating doses were tested of intravenous (IV) tocilizumab (4, 6, and 8 mg/kg) administered at day (d) 8 of a standard AML induction chemotherapy (IV idarubicine 8 mg/m2 d1 to d5 + IV cytarabine 100 mg/m2 d1 to d7). All adults (aged ≥ 18 years) with an Eastern Cooperative Oncology Group performance status of 0-2 and with a newly diagnosed (excluding patients with a favourable risk according to ELN-2017 classification if <60 year-old) or a relapsed/refractory AML were eligible. The primary objective was to determine the maximum tolerated dose of tocilizumab to administrate with a standard intensive AML induction. Safety outcomes were continuously monitored for at each participant contact. This trial is registered with ClinicalTrials.gov, NCT04547062. Findings: Between Dec 29, 2020 and Dec 1, 2022, 12 patients were enrolled, of whom 75% had an ELN-2017 high-risk profile, and were treated with tocilizumab- two patients at 4 mg/kg, two at 6 mg/kg and eight at 8 mg/kg of tocilizumab. No dose-limiting toxicity related to tocilizumab was documented. There were nine serious adverse events, none of which were related to tocilizumab, and there was no treatment-related deaths. MTD was thus not reached. Two deaths occurred during induction. In the remaining ten evaluable patients, nine responded to treatment. Interpretation: The combination of tocilizumab with standard AML intensive induction appears to be safe and resulting responses are encouraging. A dose of 8 mg/kg of tocilizumab given at day 8 of induction could be used for further phase 2/3 studies. Funding: The Leucémie Espoir Atlantique Famille (LEAF)-"Tous avec Fabien" association.

Assessment of COVID-19 Incidence and Severity Among Recipients of Allogenic Stem Cell Transplant After 1 or 2 mRNA Booster Doses During the Omicron Wave in France.

This cohort study assesses the incidence and severity of COVID-19 among vaccinated recipients of allogenic stem cell transplant in a single center after 1 or 2 messenger RNA booster doses during the Omicron wave in France.

Pre-exposure prophylaxis with tixagevimab/cilgavimab (AZD7442) prevents severe SARS-CoV-2 infection in recipients of allogeneic hematopoietic stem cell transplantation during the Omicron wave: a multicentric retrospective study of SFGM-TC.

Since the emergence of the Omicron variant of SARS-CoV-2, though considered less virulent, hospitalization and death rates among immunocompromised patients remain high, especially for poor responders to vaccination. We conducted a retrospective multicentric study to evaluate pre-exposure prophylaxis with AZD7442 (tixagevimab/cilgavimab) for preventing COVID-19 in adult allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Among the 161 patients of our cohort, 22 (14%) contracted COVID-19 after a median follow-up of 105 days, but no severe form was observed. Only one major adverse event was reported: an acute coronary syndrome, resolved without sequelae. Pending randomized controlled trial results, our data support the use of AZD7442 as pre-exposure prophylaxis for COVID-19 during Omicron wave in allo-HSCT patients who failed to develop humoral immunity to vaccination, to prevent severe and potentially lethal forms of SARS-CoV-2 infection.

Peripheral levels of monocytic myeloid-derived suppressive cells before and after first induction predict relapse and survivals in AML patients.

Myeloid Derived Suppressive Cells (MDSC) are capable to suppress innate and adaptive immune responses, thus favouring solid cancer progression. However, little is known about the role of MDSC in acute myeloid leukaemia (AML). In this monocentric prospective study, 73 adult AML patients, eligible for first-line intensive chemotherapy, were included with the aim to study the influence on long-term outcomes of peripheral blood (PB) levels of monocytic (M) MDSC (M-MDSC) assessed by flow cytometry. A percentage of peripheral M-MDSC higher than 0.55% of leukocytes at diagnosis and a decrease of M-MDSC% after induction came out both as independent negative prognostic factors for leukaemia-free and overall survival.

Strong SARS-CoV-2 T-Cell Responses after One or Two COVID-19 Vaccine Boosters in Allogeneic Hematopoietic Stem Cell Recipients.

A full exploration of immune responses is deserved after anti-SARS-CoV-2 vaccination and boosters, especially in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although several reports indicate successful humoral responses in such patients, the literature is scarce on cellular specific immunity. Here, both B- (antibodies) and T-cell responses were explored after one (V3 n = 40) or two (V4 n = 12) BNT162b2 mRNA vaccine boosters in 52 allo-HSCT recipients at a median of 755 days post-transplant (<1 year n = 9). Results were compared with those of 12 controls who had received only one booster (BNT162b2 n = 6; mRNA-1273 n = 6). All controls developed protective antibody levels (>250 BAU/mL) and anti-spike T-cell responses. Similarly, 81% of the patients developed protective antibody levels, without difference between V3 and V4 (82.5% vs. 75%, p = 0.63), and 85% displayed T-cell responses. The median frequency of anti-spike T cells did not differ either between controls or the whole cohort of patients, although it was significantly lower for V3 (but not V4) patients. COVID-19 infections were solely observed in individuals having received only one booster. These results indicate that four vaccine injections help to achieve a satisfactory level of both humoral and cellular immune protection in allo-HSCT patients.

Outcomes after allogeneic hematopoietic stem cell transplantation for adults with primary mediastinal B cell lymphoma: a SFGM-TC and LYSA study.

Background: Despite therapeutic progress, 10 to 30% of adult patients with primary mediastinal B cell lymphoma (PMBCL) are primary refractory or experience early relapse (R/R). Allogeneic stem cell transplantation (allo-HSCT) thus remains a potentially curative option in this setting.Material and Methods: In this multicenter retrospective study, the outcomes of 33 French and Belgian adult patients allo-transplanted for R/R PMBCL between January 1999 and December 2018, were examined.Results: At allo-HSCT time, patients had received a median of 3 treatment lines, 50% of them were in complete response, 40% in partial response and 10% had a progressive disease. Forty-two percent of the donors were siblings and 39% matched related. The median follow-up for alive patients was 78 months (3.5-157). Considering the whole cohort, 2-year overall survival (OS), progression free survival (PFS) and graft-versus-host disease-free/relapse-free survival (GRFS) were 48% (95%CI: 33-70), 47% (95%CI: 33-68) and 38.5% (95%CI: 25-60) respectively. Cumulative incidence of relapse and non-relapse mortality rates were respectively 34% (95%CI: 18-50) and 18% (95%CI: 7-34). Disease status at transplant was the only factor predicting survivals, patients with progressive disease showing significant lower 2-year PFS (HR: 6.12, 95%CI: 1.32-28.31, p = 0.02) and OS (HR: 7.04, 95%CI: 1.52-32.75, p = 0.013). A plateau was observed for OS and PFS after 4 years with 10 patients alive after this date, suggesting that almost one third of the patients effectively salvaged and undergoing allo-SCT could be cured.Conclusion: This study indicates that allo-HSCT is a valid therapeutic option for R/R PMBCL, providing durable remissions.

Safety and risk of febrile recurrence after early antibiotic discontinuation in high-risk neutropenic patients with haematological malignancies: a multicentre observational study.

BACKGROUND: Early antibiotic discontinuation according to the Fourth European Conference on Infections in Leukaemia (ECIL-4) recommendations is not systematically applied in high-risk neutropenic patients with haematological malignancies. METHODS: A retrospective multicentre observational study was conducted over 2 years to evaluate the safety of early antibiotic discontinuation for fever of unknown origin (FUO) during neutropenia after induction chemotherapy or HSCT, in comparison with a historical cohort. We used Cox proportional hazards models, censored on neutropenia resolution, to analyse factors associated with febrile recurrence. RESULTS: Among 147 included patients in the ECIL-4 cohort, mainly diagnosed with acute leukaemia (n = 104, 71%), antibiotics were discontinued during 170 post-chemotherapy neutropenic episodes. In comparison with the historical cohort of 178 episodes of neutropenia without antibiotic discontinuation, no significant differences were observed regarding febrile recurrences [71.2% (121/170) versus 71.3% (127/178), P = 0.97], admission in ICUs [6.5% (11/170) versus 11.2% (20/178), P = 0.17], septic shock [0.6% (1/170) versus 3.9% (7/178), P = 0.07] and 30 day mortality [1.4% (2/147) versus 2.7% (4/150), P = 0.084]. In the ECIL-4 cohort, the rate of bacteraemia in case of febrile recurrence was higher [27.1% (46/170) versus 11.8% (21/178), P < 0.01] and antibiotic consumption was significantly lower (15.5 versus 19.9 days, P < 0.001). After early antibiotic discontinuation according to ECIL-4 recommendations, enterocolitis was associated with febrile recurrence [HR = 2.31 (95% CI = 1.4-3.8), P < 0.001] and stage III-IV oral mucositis with bacteraemia [HR = 2.26 (95% CI = 1.22-4.2), P = 0.01]. CONCLUSIONS: After an FUO episode in high-risk neutropenia, compliance with ECIL-4 recommendations for early antibiotic discontinuation appears to be safe and mucosal damage was associated with febrile recurrence and bacteraemia. Prospective interventional studies are warranted to assess this strategy in high-risk neutropenic patients.

Dramatic Recovery after Etoposide Phosphate Infusion for Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome following Treatment with Tisagenlecleucel in a Young Patient with Relapsed Acute Lymphoblastic Leukemia: A Case Report.

The occurrence of a secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS) after CAR T-cell infusion is very rare and mostly fatal. Treatment recommendations for such a complication are not yet established. Here, we report the dramatic recovery of HLH/MAS following tisagenlecleucel infusion in a young patient with relapsed acute lymphoblastic leukemia using etoposide phosphate (EP). We propose that monitoring for the occurrence of HLH/MAS should be part of surveillance after CAR T-cell infusion and that EP treatment appears to be useful to control this severe and rare complication.

Impact on outcomes of mixed chimerism of bone marrow CD34+ sorted cells after matched or haploidentical allogeneic stem cell transplantation for myeloid malignancies.

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT), proposed to patients with high-risk myeloid malignancies, may ultimately fail because of disease relapse. Bone marrow (BM) CD34+ cells in Allo-HSCT recipients can be either re-emerging recipient malignant cells or donor cells attesting of hematopoietic reconstitution. In this context, investigating donor/recipient chimerism in the population of BM CD34+ sorted cells (BM-CD34+SC) was performed in 261 Allo-HSCT recipients (matched n = 145, haploidentical n = 65, matched unrelated n = 51) with myeloid malignancies. BM-CD34+SC chimerism was compared to that of whole peripheral blood (PB) cells as well as other Allo-HSCT-related parameters, and impact on relapse and survival was assessed. Thresholds of 98% donor cells for PB and 90% for BM-CD34+SC were found to allow relapse prediction. This was completed by the application of machine learning tools to explore the predictive value of these parameters in multidimensional models with repeated iterations. BM-CD34+SC mixed chimerism stood out with all these methods as the most robust predictor of relapse with a significant impact on disease-free and overall survivals even after haploidentical Allo-HSCT and/or PTCY administration. This marker therefore appears to be of great interest for the decision of preemptive treatment to avoid post-transplant relapse.

Effectiveness of a third dose of BNT162b2 anti-SARS-CoV-2 mRNA vaccine over a 6-month follow-up period in allogenic hematopoietic stem cells recipients.

This study reports the effectiveness of three injections of BNT162b2 anti-SARS-CoV-2 mRNA vaccine in 141 Allo-HSCT recipients with a median follow-up of 6 months post-third shot. We demonstrate a long-term high protection of Allo-HSCT recipients since only 2 infections and one death related to COVID-19 occurred.