Efficacy and safety of mammalian target of rapamycin inhibitors in systemic mastocytosis: A nationwide French pilot study.

Systemic mastocytosis (SM) corresponds to a rare and heterogeneous spectrum of diseases characterized by the accumulation of atypical mast cells (MCs). Advanced mastocytosis (Adv-SM) is associated with poor survival; in contrast, patients with non-advanced SM (non-Adv-SM) usually have a normal life expectancy but may experience poor quality of life. Despite recent therapeutic progress including tyrosine kinase inhibitors, new treatment options are needed for refractory and/or intolerant patients with both severely symptomatic and Adv-SM. In vitro, the mTOR pathway is activated in MCs from patients bearing the KIT D816V mutation. Furthermore, rapamycin induces the apoptosis of KIT D816V MCs selectively. In this nationwide study, we report the outcomes of patients diagnosed with SM and treated with a mammalian target of rapamycin inhibitor (imTOR) within the French National Reference Center for mastocytosis (CEREMAST). All patients registered were relapsing, treatment-refractory, or ineligible for other cytoreductive therapy. Non-Adv-SM patients received imTOR as a monotherapy (rapamycin/everolimus), and Adv-SM patients received imTOR as a monotherapy or in combination with cytarabine. The objective response rate (ORR) in non-Adv-SM was 60% (partial response in 40% and major response in 20%), including reductions in skin involvement, mediator release symptoms, and serum tryptase. In the Adv-SM group, the ORR was 20% (including one major response and one partial response, both in patients with a KIT D816V mutation), which enabled a successful bridge to allogeneic stem cell transplantation in one patient. Our results suggest that imTOR treatment has potential benefits in patients with SM harboring a KIT D816V mutation.

Involvement of the JAK-STAT pathway in the molecular landscape of tyrosine kinase fusion-negative hypereosinophilic syndromes: A nationwide CEREO study.

We investigated using a custom NGS panel of 149 genes the mutational landscape of 64 consecutive adult patients with tyrosine kinase fusion-negative hypereosinophilia (HE)/hypereosinophilic syndrome (HES) harboring features suggestive of myeloid neoplasm. At least one mutation was reported in 50/64 (78%) patients (compared to 8/44 (18%) patients with idiopathic HE/HES/HEUS used as controls; p < .001). Thirty-five patients (54%) had at least one mutation involving the JAK-STAT pathway, including STAT5B (n = 18, among which the hotspot N642H, n = 13), JAK1 (indels in exon 13, n = 5; V658F/L, n = 2), and JAK2 (V617F, n = 6; indels in exon 13, n = 2). Other previously undescribed somatic mutations were also found in JAK2, JAK1, STAT5B, and STAT5A, including three patients who shared the same STAT5A V707fs mutation and features consistent with primary polycythemia. Nearly all JAK-STAT mutations were preceded by (or associated with) myelodysplasia-related gene mutations, especially in RNA-splicing genes or chromatin modifiers. In multivariate analysis, neurologic involvement (hazard ratio [HR] 4.95 [1.87-13.13]; p = .001), anemia (HR 5.50 [2.24-13.49]; p < .001), and the presence of a high-risk mutation (as per the molecular international prognosis scoring system: HR 6.87 [2.39-19.72]; p < .001) were independently associated with impaired overall survival. While corticosteroids were ineffective in all treated JAK-STAT-mutated patients, ruxolitinib showed positive hematological responses including in STAT5A-mutated patients. These findings emphasize the usefulness of NGS for the workup of tyrosine kinase fusion-negative HE/HES patients and support the use of JAK inhibitors in this setting. Updated classifications could consider patients with JAK-STAT mutations and eosinophilia as a new "gene mutated-entity" that could be differentiated from CEL, NOS, and idiopathic HES.

Histological characterization of liver involvement in systemic mastocytosis.

BACKGROUND AND AIMS: Systemic mastocytosis (SM) is characterized by the accumulation of atypical mast cells (MCs) in organs. Liver histology of SM has been marginally described and accurate histological classification is critical, given the consequences of aggressive SM diagnosis. We aimed to describe the histological features associated with liver SM using updated tools. METHODS: Using the database of the French Reference Centre for Mastocytosis, we retrospectively identified patients with a liver biopsy (LB) and a diagnosis of SM. All LB procedures were performed according to the local physician in charge and centrally reviewed by an expert pathologist. RESULTS: A total of 28 patients were included: 6 had indolent SM, 9 had aggressive SM, and 13 had SM with an associated hematologic neoplasm. Twenty-five (89%) patients presented hepatomegaly, and 19 (68%) had portal hypertension. The LB frequently showed slight sinusoid dilatation (82%). Fibrosis was observed in 3/6 indolent SM and in almost all advanced SM cases (21/22), but none of them showed cirrhosis. A high MC burden (>50 MCs/high-power field) was correlated with elevated blood alkaline phosphatase levels (p = .030). The presence of portal hypertension was associated with a higher mean fibrosis grade (1.6 vs. 0.8 in its absence; p = .026). In advanced SM, the presence of nodular regenerative hyperplasia (NRH) was associated with decreased overall survival (9.5 vs. 46.3 months, p = .002). CONCLUSIONS: MC infiltration induced polymorphic hepatic lesions and the degree of fibrosis is associated with portal hypertension. NRH identifies a poor prognosis subgroup of patients with advanced SM. Assessing liver histology can aid in SM prognostic evaluation.

Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France registry.

The aim of this study was to assess the prevalence and the burden of difficult-to-treat primary ITP (pITP), defined by the need for another ITP treatment after romiplostim and eltrombopag. Adult patients were selected in the prospective, real-world CARMEN-France registry up to December 2021. Out of 821 adult patients with pITP, 29 had difficult-to-treat ITP (3.5%; 95% confidence interval [CI]: 2.3%-4.8% in total; 7.6%; 95% CI: 4.9%-10.2% of patients needing ≥2nd line treatment). The 3-year cumulative incidence of bleeding, infection and thrombosis was 100%, 24.1% and 13.8% respectively. The median cumulative duration of hospital stays was 31 days (median follow-up: 30.3 months).

Pathophysiologic implications of elevated prevalence of hereditary alpha-tryptasemia in all mastocytosis subtypes.

BACKGROUND: Mastocytosis and monoclonal mast cell (MC) activation syndrome (MMAS) are heterogeneous conditions characterized by the accumulation of atypical MCs. Despite the recurrent involvement of KIT mutations, the pathophysiologic origin of mastocytosis and MMAS is unclear. Although hereditary α-tryptasemia (HαT, related to TPSAB1 gene duplication) is abnormally frequent in these diseases, it is not known whether the association is coincidental or causal. OBJECTIVE: We evaluated the prevalence of HαT in all mastocytosis subtypes and MMAS and assessed the pathophysiologic association with HαT. METHODS: Clinical data, laboratory data, KIT mutations, TPSAB1 duplication (assessed by droplet digital PCR), and HαT prevalence were retrospectively recorded for all patients with mastocytosis and MMAS registered in the French national referral center database and compared to a control cohort. To increase the power of our analysis for advanced systemic mastocytosis (advSM), we pooled our cohort with literature cases. RESULTS: We included 583 patients (27 with MMAS and 556 with mastocytosis). The prevalence of HαT in mastocytosis was 12.6%, significantly higher than in the general population (5.7%, P = .002) and lower than in MMAS (33.3%, P = .02). HαT+ patients were more likely to have anaphylactic reactions and less likely to have cutaneous lesions than HαT- patients (43.0% vs 24.4%, P = .006; 57.7% vs 75.6%, respectively, P = .006). In the pooled analysis, the prevalence of HαT was higher in advSM (11.5%) than in control cohorts (5.2%, P = .01). CONCLUSION: Here we confirm the increase incidence of anaphylaxis in HαT+ mastocytosis patients. The increased prevalence of HαT in all subtypes of systemic mastocytosis (including advSM) is suggestive of pathophysiologic involvement.

Severe adult hemophagocytic lymphohistiocytosis (HLHa) correlates with HLH-related gene variants.

BACKGROUND: The contribution of genetic factors to the severity of adult hemophagocytic lymphohistiocytosis (HLHa) remains unclear. OBJECTIVE: We sought to assess a potential link between HLHa outcomes and HLH-related gene variants. METHODS: Clinical characteristics of 130 HLHa patients (age ≥ 18 years and HScore ≥ 169) and genotype of 8 HLH-related genes (LYST, PRF1, UNC13-D, STX11, STXBP2, RAB27A, XIAP, and SAP) were collected. A total of 34 variants found in only 6 genes were selected on the basis of their frequency and criteria predicted to impair protein function. Severity was defined by refractory disease to HLH treatment, death, or transfer to an intensive care unit. RESULTS: HLHa-associated diseases (ADs) were neoplasia (n = 49 [37.7%]), autoimmune/inflammatory disease (n = 33 [25.4%]), or idiopathic when no AD was identified (n = 48 [36.9%]). Infectious events occurred in 76 (58.5%) patients and were equally distributed in all ADs. Severe and refractory HLHa were observed in 80 (61.5%) and 64 (49.2%) patients, respectively. HScore, age, sex ratio, AD, and infectious events showed no significant association with HLHa severity. Variants were identified in 71 alleles and were present in 56 (43.1%) patients. They were distributed as follows: 44 (34.4%), 9 (6.9%), and 3 (2.3%) patients carrying 1, 2, and 3 variant alleles, respectively. In a logistic regression model, only the number of variants was significantly associated with HLHa severity (1 vs 0: 3.86 [1.73-9.14], P = .0008; 2-3 vs 0: 29.4 [3.62-3810], P = .0002) and refractoriness (1 vs 0: 2.47 [1.17-5.34], P = .018; 2-3 vs 0: 13.2 [2.91-126.8], P = .0003). CONCLUSIONS: HLH-related gene variants may be key components to the severity and refractoriness of HLHa.

Serious infections in patients with VEXAS syndrome: data from the French VEXAS registry.

INTRODUCTION: Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is an acquired autoinflammatory monogenic disease with a poor prognosis whose determinants are not well understood. We aimed to describe serious infectious complications and their potential risk factors. METHODS: Retrospective multicentre study including patients with VEXAS syndrome from the French VEXAS Registry. Episodes of serious infections were described, and their risk factors were analysed using multivariable Cox proportional hazards models. RESULTS: Seventy-four patients with 133 serious infections were included. The most common sites of infection were lung (59%), skin (10%) and urinary tract (9%). Microbiological confirmation was obtained in 76%: 52% bacterial, 30% viral, 15% fungal and 3% mycobacterial. Among the pulmonary infections, the main pathogens were SARS-CoV-2 (28%), Legionella pneumophila (21%) and Pneumocystis jirovecii (19%). Sixteen per cent of severe infections occurred without any immunosuppressive treatment and with a daily glucocorticoid dose ≤10 mg. In multivariate analysis, age >75 years (HR (95% CI) 1.81 (1.02 to 3.24)), p.Met41Val mutation (2.29 (1.10 to 5.10)) and arthralgia (2.14 (1.18 to 3.52)) were associated with the risk of serious infections. JAK inhibitors were most associated with serious infections (3.84 (1.89 to 7.81)) compared with biologics and azacitidine. After a median follow-up of 4.4 (2.5-7.7) years, 27 (36%) patients died, including 15 (56%) due to serious infections. CONCLUSION: VEXAS syndrome is associated with a high incidence of serious infections, especially in older patients carrying the p.Met41Val mutation and treated with JAK inhibitors. The high frequency of atypical infections, especially in patients without treatment, may indicate an intrinsic immunodeficiency.

[Mobilization and conditioning protocols actualization for autologous stem cell transplantation for autoimmune diseases: Guidelines from MATHEC-SFGM-TC]. / Actualisation des protocoles de mobilisation et conditionnement pour la pratique des autogreffes de cellules souches hématopoïétiques chez les patients atteints de maladies auto-immunes : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (MATHEC-SFGM-TC).

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organized the 13th workshop on hematopoietic stem cell transplantation clinical practices harmonization procedures in September 2022 in Lille, France. The aim of this workshop is to update the mobilization and conditioning protocols for autologous hematopoietic stem cell transplantation for autoimmune diseases, and to specify contraindications for transplant, conditioning regimen selection, immunosuppressive treatment discontinuation before mobilization and disease-specific surveillance.

Liver disease in germline mutations of telomere-related genes: Prevalence, clinical, radiological, pathological features, outcome, and risk factors.

BACKGROUND AND AIM: Germline mutations of telomere-related genes (TRG) induce multiorgan dysfunction, and liver-specific manifestations have not been clearly outlined. We aimed to describe TRG mutations-associated liver diseases. APPROACH AND RESULTS: Retrospective multicenter analysis of liver disease (transaminases > 30 IU/L and/or abnormal liver imaging) in patients with TRG mutations. Main measurements were characteristics, outcomes, and risk factors of liver disease in a TRG mutations cohort. The prevalence of liver disease was compared to a community-based control group (n = 1190) stratified for age and matched 1:3 for known risk factors of liver disease. Among 132 patients with TRG mutations, 95 (72%) had liver disease, with associated lung, blood, skin, rheumatological, and ophthalmological TRG diseases in 82%, 77%, 55%, 39%, and 30% of cases, respectively. Liver biopsy was performed in 52/95 patients, identifying porto-sinusoidal vascular disease in 48% and advanced fibrosis/cirrhosis in 15%. After a follow-up of 21 months (12-54), ascites, hepato-pulmonary syndrome, variceal bleeding, and HCC occurred in 14%, 13%, 13%, and 2% of cases, respectively. Five-year liver transplantation-free survival was 69%. A FIB-4 score ≥ 3·25 and ≥1 risk factor for cirrhosis were associated with poor liver transplantation-free survival. Liver disease was more frequent in patients with TRG mutations than in the paired control group [80/396, (20%)], OR 12.9 (CI 95%: 7.8-21.3, p < 0.001). CONCLUSIONS: TRG mutations significantly increase the risk of developing liver disease. Although symptoms may be mild, they may be associated with severe disease. Porto-sinusoidal vascular disease and cirrhosis were the most frequent lesions, suggesting that the mechanism of action is multifactorial.

Combining thrombopoietin receptor agonists with immunosuppressive drugs in adult patients with multirefractory immune thrombocytopenia, an update on the French experience.

Combining drugs could be an effective option for treating multirefractory ITP, that is, patients not responding to rituximab, thrombopoietin receptor agonists (TPO-RA) and splenectomy. We conducted a retrospective, multicenter, observational study including multirefractory ITP patients who received a combination of a TPO-RA and an immunosuppressive drug. We included 39 patients (67% women, median age 59 years [range 21-96]), with a median ITP duration of 57 months [3-393] and a median platelet count at initiation of 10 × 109 /L [1-35]. The combination regimen was given for a median duration of 12 months [1-103] and included eltrombopag (51%) or romiplostim (49%), associated with mycophenolate mofetil (54%), azathioprine (36%), cyclophosphamide (5%), cyclosporin (3%) or everolimus (3%). Overall, 30 patients (77%) achieved at least a response (platelet count ≥30 × 109 /L and at least doubling baseline during at least 3 months), including 24 complete responses (platelet count >100 × 109 /L during at least 3 months) with a median time to response of 30 days [7-270] and a median duration of response of 15 months [4-63]. Severe adverse event related to ITP treatment was observed in 31%. In conclusion, this study confirms that some patients with multirefractory ITP can achieve long lasting response with this combination.

French guidelines for the etiological workup of eosinophilia and the management of hypereosinophilic syndromes.

Eosinophilic-related clinical manifestations are protean and the underlying conditions underpinning eosinophilia are highly diverse. The etiological workup of unexplained eosinophilia/hypereosinophilia can be challenging, and can lead sometimes to extensive, inappropriate, costly and/or invasive investigations. To date, guidelines for the etiological workup and management of eosinophilia are mainly issued by hematologists, and thus mostly cover the scope of clonal hypereosinophilic syndromes (HES). Here, thanks to an extensive literature review, and thanks to the joint work of a large panel of experts involving physicians from both adult and pediatric medicine and from various subspecialties (as well as a representative of a patients' association representative), we provide recommendations for both the step-by step diagnostic workup of eosinophilia (whether unexplained or within specific contexts) as well as the management and follow-up of the full spectrum of eosinophilic disorders (including clonal, reactive, lymphocytic and idiopathic HES, as well as single-organ diseases). Didactic prescription summaries intended to facilitate the prescription of eosinophil-targeted drugs are also provided, as are practical diagnostic and therapeutic algorithms. Lastly, this set of recommendations also includes a summary intended for general practitioners, as well as an overview of the therapeutic patient education program set up by the French reference center for HES. Further updates will be mandatory as new validated information emerges.

Prolonged response after TPO-RA discontinuation in primary ITP: results of a prospective multicenter study.

Sustained response off treatment (SROT) after thrombopoietin receptor agonist (TPO-RA) discontinuation has been reported in immune thrombocytopenia (ITP). This prospective multicenter interventional study enrolled adults with persistent or chronic primary ITP and complete response (CR) on TPO-RAs. The primary end point was the proportion of patients achieving SROT (platelet count >30 × 109/L and no bleeding) at week 24 (W24) with no other ITP-specific medications. Secondary end points included the proportion of sustained CR off-treatment (SCROT, platelet count >100 × 109/L and no bleeding) and SROT at W52, bleeding events, and pattern of response to a new course of TPO-RAs. We included 48 patients with a median age of 58.5 years; 30 of 48 had chronic ITP at TPO-RA initiation. In the intention-to-treat analysis, 27 of 48 achieved SROT, 15 of 48 achieved SCROT at W24; 25 of 48 achieved SROT, and 14 of 48 achieved SCROT at W52. No severe bleeding episode occurred in patients who relapsed. Among patients rechallenged with TPO-RA, 11 of 12 achieved CR. We found no significant clinical predictors of SROT at W24. Single-cell RNA sequencing revealed enrichment of a tumor necrosis factor α signaling via NF-κB signature in CD8+ T cells of patients with no sustained response after TPO-RA discontinuation, which was further confirmed by a significant overexpression of CD69 on CD8+ T cells at baseline in these patients as compared with those achieving SCROT/SROT. Our results strongly support a strategy based on progressive tapering and discontinuation of TPO-RAs for patients with chronic ITP who achieved a stable CR on treatment. This trial was registered at www.clinicaltrials.gov as #NCT03119974.

[Vaccination before and after autologous hematopoietic cell transplantation for autoimmune diseases: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (MATHEC-SFGM-TC)]. / Vaccinations avant et après greffe de cellules hématopoïétiques autologues chez les patients atteints de maladies auto-immunes : propositions du groupe Maladies Auto-immunes et Thérapie Cellulaire de la SFGM-TC.

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organized the 12th workshop on hematopoietic stem cell transplantation clinical practices harmonization procedures on September 2021 in Lille, France. In the absence of specific national or international recommendation, the French working group for autologous stem Cell transplantation in Auto-immune Diseases (MATHEC) proposed guidances for vaccinations of patients undergoing autologous hematopoietic stem cell transplantation for autoimmune disease, including in the context of SARS-Cov-2 pandemic.

Pleuropulmonary Manifestations of Vacuoles, E1 Enzyme, X-Linked, Autoinflammatory, Somatic (VEXAS) Syndrome.

BACKGROUND: The vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is a newly identified autoinflammatory disorder related to somatic UBA1 mutations. Up to 72% of patients may show lung involvement. RESEARCH QUESTION: What are the pleuropulmonary manifestations in VEXAS syndrome? STUDY DESIGN AND METHODS: One hundred fourteen patients were included in the French cohort of VEXAS syndrome between November 2020 and May 2021. Each patient included in the study who had an available chest CT scan was discussed in an adjudication multidisciplinary team and classified as showing potentially pleuropulmonary-specific involvement of VEXAS syndrome or others. RESULTS: Fifty-one patients had a CT scan available for review and 45 patients (39%) showed pleuropulmonary abnormalities on chest CT scan that were considered related to VEXAS syndrome after adjudication. Most patients were men (95%) with a median age 67.0 years at the onset of symptoms. Among these 45 patients, 44% reported dyspnea and 40% reported cough. All 45 patients showed lung opacities on chest CT scan (including ground-glass opacities [87%], consolidations [49%], reticulation [38%], and septal lines [51%]) and 53% of patients showed pleural effusion. Most patients showed improvement with prednisone, but usually required > 20 mg/d. The main clinical and biological features as well the median survival did not differ between the 45 patients with pleuropulmonary involvement and the rest of the cohort, suggesting that the prevalence of pleuropulmonary involvement might have been underdiagnosed in the rest of the cohort. INTERPRETATION: Pulmonary manifestations are frequent in VEXAS syndrome, but rarely are at the forefront. The initial outcome is favorable with prednisone and does not seem to lead to pulmonary fibrosis.

Reduced peripheral blood dendritic cell and monocyte subsets in MDS patients with systemic inflammatory or dysimmune diseases.

BACKGROUND: Systemic inflammatory and autoimmune diseases (SIADs) occur in 10-20% of patients with myelodysplastic syndrome (MDS). Recently identified VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome, associated with somatic mutations in UBA1 (Ubiquitin-like modifier-activating enzyme 1), encompasses a range of severe inflammatory conditions along with hematological abnormalities, including MDS. The pathophysiological mechanisms underlying the association between MDS and SIADs remain largely unknown, especially the roles of different myeloid immune cell subsets. The aim of this study was to quantitatively evaluate peripheral blood myeloid immune cells (dendritic cells (DC) and monocytes) by flow cytometry in MDS patients with associated SIAD (n = 14, most often including relapsing polychondritis or neutrophilic dermatoses) and to compare their distribution in MDS patients without SIAD (n = 23) and healthy controls (n = 7). Most MDS and MDS/SIAD patients had low-risk MDS. Eight of 14 (57%) MDS/SIAD patients carried UBA1 somatic mutations, defining VEXAS syndrome.Compared with MDS patients, most DC and monocyte subsets were significantly decreased in MDS/SIAD patients, especially in MDS patients with VEXAS syndrome. Our study provides the first overview of the peripheral blood immune myeloid cell distribution in MDS patients with associated SIADs and raises several hypotheses: possible redistribution to inflammation sites, increased apoptosis, or impaired development in the bone marrow.

Ibrutinib as a treatment of hematologic autoimmune disorders in patients with indolent B-cell lymphoma.

BACKGROUND: Autoimmune conditions in B-cell lymphomas are frequent. Steroids are standard of care, but many patients require other immunosuppressive agents. Ibrutinib is a Bruton Tyrosine Kinase inhibitor that is approved for B-cell indolent lymphoma treatment. We evaluated the use of ibrutinib in previously treated hematologic immune manifestations associated with B-cell lymphomas. RESULTS: We conducted a retrospective multicentric observational study. Patients presenting with active, relapsed/refractory B-cell lymphoma associated hematological immune manifestation (autoimmune cytopenia, acquired immune-mediated bleeding disorders) were included. Twenty-five patients were identified. Median age at ibrutinib introduction was 69 years (range 44-84) and median number of previous treatment lines before ibrutinib was 2 (1-7). Twenty-two patients (88%) were on concomitant stable treatment at inclusion. Within a median exposure of 8 months (2-35), overall response rate to ibrutinib on immune manifestations was 76% (95% CI, 54.9-90.6); complete response rate 44%. Fourteen patients (63%) were able to be weaned from concomitant treatments. Fourteen patients (56%) presented treatment-related adverse events, mostly Grade 1 or 2. CONCLUSIONS: Ibrutinib in this setting provides good efficacy and safety profile. Clinical trials are needed to define subgroups of patients who will benefit from this strategy and establish its place in the therapeutic arsenal.