Effective Anti-SARS-CoV-2 Immune Response in Patients With Clonal Mast Cell Disorders

BACKGROUND

Mast cells are key players in innate immunity and the T_H2 adaptive immune response. The latter counterbalances the T_H1 response, which is critical for antiviral immunity. Clonal mast cell activation disorders (cMCADs, such as mastocytosis and clonal mast cell activation syndrome) are characterized by abnormal mast cell accumulation and/or activation. No data on the antiviral immune response in patients with MCADs have been published.

OBJECTIVE

To study a comprehensive range of outcomes in patients with cMCAD with PCR- or serologically confirmed coronavirus disease 2019 and to characterize the specific anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune response in this setting.

METHODS

Clinical follow-up and outcome data were collected prospectively over a 12-month period by members of the French Centre de Référence des Mastocytoses rare disease network. Anti-SARS-CoV-2-specific T-cell activity was measured with an ELISA, and humoral responses were evaluated by assaying circulating levels of specific IgG, IgA, and neutralizing antibodies.

RESULTS

Overall, 32 patients with cMCAD were evaluated. None required noninvasive or mechanical ventilation. Two patients were admitted to hospital for oxygen and steroid therapy. The SARS-CoV-2-specific immune response was characterized in 21 of the 32 patients. Most had high counts of circulating SARS-CoV-2-specific, IFN-γ-producing T cells and high titers of neutralizing antispike IgGs. The patients frequently showed spontaneous T-cell IFN-γ production in the absence of stimulation; this production was correlated with basal circulating tryptase levels (a marker of the mast cell burden).

CONCLUSIONS

Patients with cMCADs might not be at risk of severe coronavirus disease 2019, perhaps due to their spontaneous production of IFN-γ.

Determinants of CD19-positive vs CD19-negative relapse after tisagenlecleucel for B-cell acute lymphoblastic leukemia

Tisagenlecleucel therapy has shown promising efficacy for relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, relapses occur in 30-50% of patients. Determinants for CD19^pos versus CD19^neg relapses are poorly characterized. We report on 51 patients with R/R BCP-ALL (median age 17 years) infused with tisagenlecleucel after lymphodepletion. Complete remission rate at D28 was 96%. Prior blinatumomab increased the risk of early failure at D28. The 18-month cumulative incidence of relapse (CIR), event-free survival (EFS), and overall survival (OS) were 51%, 44%, and 74%, respectively, at a median follow-up of 15.5 months. Factors associated with a high tumor burden (occurrence of cytokine release syndrome) and prior blinatumomab were associated with an increased CIR, and a shorter EFS and OS. Pre-lymphodepletion high disease burden (MRD ≥ 10^-2, SHR 10.4, p = 0.03) and detectable MRD at D28 (SHR 7.2, p = 0.006) correlated with an increased risk of CD19^neg relapse. Low disease burden (SHR 5.3, p = 0.03) and loss of B-cell aplasia (BCA) (SHR 21.7, p = 0.004) predicted an increased risk of CD19^pos relapses. These data highlight the impact of prior therapy on patient outcome. Finally, detectable MRD at D28 and loss of BCA both define patients at high risk of relapse for whom additional interventions are needed.

Epidemiology, clinical picture and long-term outcomes of FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia: Data from 151 patients

FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia (F/P+ MN-eo) is a rare disease: robust epidemiological data are lacking and reported issues are scarce, of low sample-size and limited follow-up. Imatinib mesylate (IM) is highly efficient but no predictive factor of relapse after discontinuation has yet been identified. One hundred and fifty-one patients with F/P+ MN-eo (143 males; mean age at diagnosis 49 years; mean annual incidence: 0.18 case per million population) were included in this retrospective nationwide study involving all French laboratories who perform the search of F/P fusion gene (study period: 2003-2019). The main organs involved included the spleen (44%), skin (32%), lungs (30%), heart (19%) and central nervous system (9%). Serum vitamin B12 and tryptase levels were elevated in 74/79 (94%) and 45/57 (79%) patients, respectively, and none of the 31 patients initially treated with corticosteroids achieved complete hematologic remission. All 148 (98%) IM-treated patients achieved complete hematologic and molecular (when tested, n = 84) responses. Forty-six patients eventually discontinued IM, among whom 20 (57%) relapsed. In multivariate analysis, time to IM initiation (continuous HR: 1,01 [0.99-1,03]; P = .05) and duration of IM treatment (continuous HR: 0,97 [0,95-0,99]; P = .004) were independent factors of relapse after discontinuation of IM. After a mean follow-up of 80 (56) months, the 1, 5- and 10-year overall survival rates in IM-treated patients were 99%, 95% and 84% respectively. In F/P+ MN-eo, prompt initiation of IM and longer treatment durations may prevent relapses after discontinuation of IM.

Quality risk management of the chimeric antigen receptor T cell pharmaceutical circuit in one of the first qualified European centers

BACKGROUND AIMS

According to European Directive 2001/83/EC, chimeric antigen receptor T (CAR T) cells belong to a new class of medicines referred to as advanced therapy medicinal products (ATMPs). The specific features and complexity of these products require a total reorganization of the hospital circuit, from cell collection from the patient to administration of the final medicinal product. In France, at the cell stage, products are under the responsibility of a cell therapy unit (CTU) that controls, manipulates (if necessary) and ships cells to the manufacturing site. However, the final product is a medicinal product, and as with any other medicine, ATMPs have to be received, stored and further reconstituted for final distribution under the responsibility of the hospital pharmacy. The aim of our work was to perform a risk analysis of this circuit according to International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Q9 guidelines on quality risk management.

METHODS

We evaluated the activities carried out by the Saint-Louis Hospital CTU and pharmacy. Process mapping was established to trace all the steps of the circuit and to identify potential risks or failures. The risk analysis was performed according to failure mode, effects and criticality analysis. The criticality of each risk (minor [Mi], moderate [Mo], significant [S] or major [Ma]) was scored, and corrective actions or preventive actions (CAPAs) for Mo, S and Ma risks were proposed.

RESULTS

We identified five Mo, six S and no Ma risks for the CTU part of the process. The most frequent risk was traceability failure. To reduce its frequency, we developed and validated software dedicated to ATMP activities. Another S risk was non-compliance of CAR T cell-specific steps due to the significant variability between companies. Our CAPA process was to implement procedures and design information sheets specific to each CAR T-cell program. In addition, critical steps were added to the ATMP software. Our CAPA process allowed us to reduce the criticality of identified risks to one Mi, seven Mo and three S. For the pharmacy part of the process, five Mo, two S and one Ma risk were identified. The most critical risk was compromised integrity of the CAR T-cell bag at the time of thawing. In case of unavailability of a backup bag, we designed and validated a degraded mode of operation allowing product recovery. In this exceptional circumstance, an agreement has to be signed between the physician, pharmacy, CTU and sponsor or marketing authorization holder. The implemented CAPA process allowed us to reduce the criticality of risks to three Mi and five Mo.

CONCLUSIONS

Our risk analysis identified several Mo and S risks but only one Ma risk. The implementation of the CAPA process allowed for controlling some risks by decreasing their frequency and/or criticality or by increasing their detectability. The close collaboration between the CTU and pharmacy allows complete traceability of the CAR T-cell circuit, which is essential to guarantee safe use.

Long-term outcomes and risk factor analysis of steroid-refractory graft versus host disease after hematopoietic stem cell transplantation

Steroid-refractory graft versus host disease (GVHD) represents a fearsome complication after allogeneic hematopoietic stem cell transplantation (HSCT). We conducted a retrospective study on outcomes and risk factors associated with acute and chronic steroid-refractory GVHD in a large cohort of 1207 patients receiving HSCT in Saint Louis Hospital between 2007 and 2017. Among patients who developed an acute and/or a chronic GVHD, the cumulative incidences of acute and chronic steroid-refractory disease were 31% and 48%, respectively, at day +100 and 1-year post-HSCT. Through a multivariable analysis we selected several risk factors associated with the development of a steroid-refractory disease. For acute GVHD steroid refractoriness, we identified (1) a very high disease risk index, (2) an unrelated donor, (3) the absence of in vivo T-depletion as GVHD prophylaxis, and (4) a reduced intensity conditioning regimen. For chronic GVHD, (1) the use of peripheral blood stem cells, (2) unrelated donors, and (3) absence of in vivo T-depletion were more likely associated with a steroid-refractory disease. After the construction of a multistate dynamic model, we found that the probability of being alive without relapse after the resolution of all GVHD episodes was about 36% in the long term.

Pre-transplant donor CD4- invariant NKT cell expansion capacity predicts the occurrence of acute graft-versus-host disease

Clinically useful pre-transplant predictive factors of acute graft-versus-host-disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-SCT) are lacking. We prospectively analyzed HSC graft content in CD34⁺, NK, conventional T, regulatory T and invariant natural killer T (iNKT) cells in 117 adult patients before allo-SCT. Results were correlated with occurrence of aGVHD and relapse. In univariate analysis, iNKT cells were the only graft cell populations associated with occurrence of aGVHD. In multivariate analysis, CD4^- iNKT/T cell frequency could predict grade II-IV aGVHD in bone marrow and peripheral blood stem cell (PBSC) grafts, while CD4^- iNKT expansion capacity was predictive in PBSC grafts. Receiver operating characteristic analyses determined the CD4^- iNKT expansion factor as the best predictive factor of aGVHD. Incidence of grade II-IV aGVHD was reduced in patients receiving a graft with an expansion factor above versus below 6.83 (9.7 vs 80%, P<0.0001), while relapse incidence at two years was similar (P=0.5).The test reached 94% sensitivity and 100% specificity in the subgroup of patients transplanted with human leukocyte antigen 10/10 PBSCs without active disease. Analysis of this CD4^- iNKT expansion capacity test may represent the first diagnostic tool allowing selection of the best donor to avoid severe aGVHD with preserved graft-versus-leukemia effect after peripheral blood allo-SCT.

[Vascular myeloproliferative neoplasm with normal cell blood count: Exploration and medical management]

Negative BCR ABL myeloproliferative neoplasm (MPN) such as polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MFP) are clonal hematological malignancies and may lead to a high risk of venous, arterial or microcirculatory thrombosis. Atypical sites of thrombosis can sometimes reveal the neoplasm disorder. Their diagnoses are a major issue because of the propensity to develop acute myeloid leukemia and/or myelofibrosis. The acquired JAK2V617F variant (Janus kinase 2; 9p24) is a prevalent MPN and also a sensitive marker for PV diagnosis (95% positive mutation), but not specific since found in approximately 50% of patients with ET and MFP.

PATIENT AND METHODS

We present a diagnostic and a therapeutic approach based on one patient with microcirculatory ischemic manifestations in the toes, and who had strictly normal cell blood counts and was positive for JAK2V617F mutation: thrombotic risk factor evaluation; bone marrow biopsy; red cell adhesion assays. These experimental assays are promising for the development of new therapeutics in MPN; they assess red cell adherence to the vascular endothelium after the phosphorylation of Lu/BCAM subsequent to a positive JAK2V617F mutation.

RESULTS

Compared with controls, our patient exhibited increased Lu/BCAM receptor phosphorylation and red blood cell adhesion.

CONCLUSION

This development may lead to improved care for patients with thrombotic manifestations, normal blood cell counts, and a positive JAK2V617F mutation: multidisciplinary management, including regular hematological monitoring, could lead to the introduction of a cytoreductive treatment.

Chronic myelomonocytic leukemia as a cause of fatal uncontrolled inflammation in familial Mediterranean fever

We report on a familial Mediterranean fever (FMF) patient homozygous for p.M694V in the MEFV gene who developed chronic myelomonocytic leukemia (CMML) leading to an uncontrolled and fatal inflammatory syndrome. Plasma levels of IL-6 and IL-18 were found to be very high, as compared to healthy controls and CMML-free FMF patients.

Our study unveils the interplay between two different disorders involving the same target cells, suggesting that in myelodysplasia with inflammatory manifestations, mutations in genes causing autoinflammatory syndromes, like MEFV, can be present and thus could be sought. Early chemotherapy with interleukin inhibitors could be proposed in such unusual situations.