JAK inhibition for CD3- CD4+ lymphocytic-variant hypereosinophilic syndrome.

Alternatives are urgently needed in patients with CD3- CD4+ lymphocytic-variant hypereosinophilic syndrome (L-HES) requiring high-level steroids or who are unresponsive and/or intolerant to conventional alternative therapies. We report five L-HES patients (44-66 years) with cutaneous involvement (n = 5) and persistent eosinophilia (n = 3) despite conventional therapies, who successfully received JAK inhibitors (tofacitinib n = 1, ruxolitinib n = 4). JAKi led to complete clinical remission in the first 3 months in all (with prednisone withdrawal in four). Absolute eosinophil counts normalized in cases receiving ruxolitinib, while reduction was partial under tofacitinib. After switch from tofacitinib to ruxolitinib, complete clinical response persisted despite prednisone withdrawal. The clone size remained stable in all patients. After 3-13 months of follow-up, no adverse event was reported. Prospective clinical trials are warranted to examine the use of JAKi in L-HES.

Biologic therapies for hypereosinophilic disorders: From tyrosine kinase inhibitors to monoclonal antibodies. Towards an increasingly customized management?

Hypereosinophilic syndromes (HES) encompass a wide range of disorders characterized by persistent peripheral blood hypereosinophilia (HE) (i.e., an eosinophil count ≥1.5 × 109/L and ≥ 10% eosinophils preferably with a minimal duration of 6 months if documentation is available) associated with organ damage and/or dysfunction attributable to tissue eosinophilic infiltrate and release of granule contents. In most cases, HE is associated with atopic conditions/allergies, parasitic infections, medications, autoimmune disorders and/or solid tumors in most cases. More rarely, it can be one of the dominant manifestations of an underlying myeloid/lymphoid neoplasm. With regard to hematological forms, in recent decades the advances in understanding the pathogenic aspects of HES have led to a growing interest in these diseases, and in the 2016 WHO classification multiple subgroups were defined according to the molecular profile with the aim of better characterizing these syndromes and establishing which patients will benefit from specific pharmacological targeted therapies. This review article will provide a comprehensive overview of possible therapeutic approaches for HES in the light of each specific molecular alteration, considering both tyrosine kinase inhibitors and monoclonal antibodies, either implemented in clinical practice or currently still under development.

Targeted Anti-IL-5 Therapies and Future Therapeutics for Hypereosinophilic Syndrome and Rare Eosinophilic Conditions.

Eosinophilic inflammation is a component of many atopic diseases such as asthma, and biologics targeting eosinophils have been shown to be effective in subsets of these patients. However, there also are conditions in which eosinophils are the key inflammatory cells responsible for driving tissue damage. In these eosinophilic diseases such as hyper-eosinophilic syndrome, eosinophilic esophagitis, and eosinophilic granulomatosis with polyangiitis (EGPA), the development of biologics inhibiting eosinophilic inflammation have offered targeted therapeutic strategies for patients that have not responded well to typical first line drugs, which often have significant adverse side effects with poor disease modification or recurrent relapse with significant morbidity. IL-5 has long been recognized as the key inflammatory cytokine involved in the priming and survival of eosinophils and their proliferation and maturation in eosinophilic disease. There are a number of trials and case series demonstrating the immunomodulatory benefits of anti-IL-5 therapies in these diseases with good clinical responses. Yet, due to the heterogeneity and rarity of these conditions, anti-IL-5 therapies have not resulted in disease remission for all patients. Clearly, further research into the use of anti-IL-5 therapies in various eosinophilic diseases is needed and ongoing investigation into other immune mechanisms underlying chronic eosinophilic diseases may provide alternative therapies for these challenging conditions.

Discovery of a Locally and Orally Active CXCL12 Neutraligand (LIT-927) with Anti-inflammatory Effect in a Murine Model of Allergic Airway Hypereosinophilia.

We previously reported Chalcone-4 (1) that binds the chemokine CXCL12, not its cognate receptors CXCR4 or CXCR7, and neutralizes its biological activity. However, this neutraligand suffers from limitations such as poor chemical stability, solubility, and oral activity. Herein, we report on the discovery of pyrimidinone 57 (LIT-927), a novel neutraligand of CXCL12 which displays a higher solubility than 1 and is no longer a Michael acceptor. While both 1 and 57 reduce eosinophil recruitment in a murine model of allergic airway hypereosinophilia, 57 is the only one to display inhibitory activity following oral administration. Thereby, we here describe 57 as the first orally active CXCL12 neutraligand with anti-inflammatory properties. Combined with a high binding selectivity for CXCL12 over other chemokines, 57 represents a powerful pharmacological tool to investigate CXCL12 physiology in vivo and to explore the activity of chemokine neutralization in inflammatory and related diseases.

Hypereosinophilic Syndrome Subtype Predicts Responsiveness to Glucocorticoids.

BACKGROUND: Glucocorticoids (GCs) are considered first-line treatment for platelet-derived growth factor α (PDGFRA)-negative hypereosinophilic syndromes (HESs). Despite this, little is known about clinical predictors of GC responsiveness in HES. OBJECTIVE: Knowledge of clinical and laboratory predictors of GC response before initiation of GC could lead to more rational selection of subjects with HES for whom earlier institution of second-line and alternative therapies would be appropriate. METHODS: Response to GC, as defined by the reduction of the absolute eosinophil count to below 1000/mm3 and control of symptoms, was assessed by a retrospective chart review of subjects with PDGFRA-negative HES evaluated on an institutional review board-approved protocol. Demographic, clinical, and laboratory parameters obtained before institution of GC, as well as final diagnosis, were evaluated to determine predictors of GC response. Proportional odds models were used for univariate and multivariate assessment of predictors with permutation adjusted P values to correct for multiple comparisons. RESULTS: A total of 164 subjects with PDGFRA-negative HES were categorized according to GC response. Of them, 39% of the subjects responded to low dose (≤10 mg) prednisone, 9% did not respond to GC, and the remainder (52%) had variable responses to GC. The HES subtype diagnosis was the best predictor of response to GC with myeloid forms and lymphocytic variants of HES being the least responsive to GC. CONCLUSIONS: In a large cohort of well-characterized subjects with HES, the odds of response to GC was predicted by HES subtype. Using this model, clinicians may more readily proceed to second-line agents in subjects with confirmed lymphocytic or myeloid forms of HES.

Hypereosinophilic syndrome presenting with multiple organ infiltration and deep venous thrombosis: A case report and literature review.

BACKGROUND: Hypereosinophilic syndrome (HES) can be fatal, particularly when eosinophils infiltrate vital organs and/or if extensive thrombosis develops. However there are no standard recommendations for the use of anticoagulant therapy of HES in the setting of thrombosis. METHODS: We herein present a case of a 46-year-old female who presented with marked peripheral eosinophilia with symptoms of multi-organ infiltration and extensive deep venous thrombosis (DVT). In this case, evaluation was carried out before the diagnosis was established, and timely standard-dose corticosteroids combined with a new oral anticoagulant (NOAC) therapy were carried out. RESULTS: These measures resulted in a rapid response and long-term disease control. CONCLUSION: Although there are no data to support which anticoagulant is preferred in this setting, this case indicates that the new oral anticoagulants may play an important role in the treatment of thrombosis in HES.

Mepolizumab in eosinophilic disorders.

Mepolizumab (Bosatria(®), GlaxoSmithKline) is a biologic agent developed to treat asthma. It represents a humanized monoclonal antibody of IgG1 κ type, which targets human IL-5 and thus prevents its interaction with the α-chain of the IL-5 receptor. To date, it has not been approved for use in any eosinophil-related disorder; however, several studies have suggested some therapeutic benefit across a spectrum of eosinophil-related disorders. This article evaluates the currently available preclinical and clinical studies, and the impact of mepolizumab against a variety of eosinophilic disorders.

Novel therapies for hypereosinophilic syndromes.

BACKGROUND: Conventional therapies (corticosteroids, cytotoxic agents or interferon-a) or newer compounds such imatinib are used specifically in subsets of hypereosinophilic syndromes (HES). However other therapies are still needed in this condition. OBJECTIVE: To review the novel therapies for HES discussing their advantages and shortcomings. METHODS AND RESULTS: Preclinical and clinical data on novel tyrosine kinase inhibitors, anti-IL -5 antibodies or anti-CD52 antibodies (alemtuzumab) are analysed. The former might represent appropriate options in case of imatinib resistance; the efficacy of anti-IL-5 monoclonal antibodies therapy is limited by the occurrence of rebound eosinophilia and alemtuzumab might be a promising anti-eosinophil therapy for all HES subsets. CONCLUSION: Some of the novel therapies might become appropriate therapeutic options for HES.

Current strategies in the management of hypereosinophilic syndrome, including mepolizumab.

BACKGROUND: Patients with hypereosinophilic syndrome (HES) vary considerably in their clinical presentation with regard to the severity and pattern of end-organ involvement. Clinical manifestations range from nonspecific symptoms to life-threatening, multisystem damage caused by eosinophil infiltration and local release of proinflammatory mediators and toxic granule products from these invading cells. The primary objective of treatment is to reduce blood and tissue eosinophilia and prevent eosinophil-mediated tissue damage as safely as possible. Systemic corticosteroids, such as prednisone, are first-line therapy for the management of patients with symptomatic HES who lack the Fip1-like 1-platelet-derived growth factor receptor-alpha (FIP1L1-PDGFRA) gene fusion mutation. The tyrosine kinase inhibitor, imatinib, is first-line treatment for FIP1L1-PDGFRA-positive patients). Because of the toxicity and serious side-effects that can occur with oral corticosteroids, alternative therapies may need to be introduced to reduce the cumulative corticosteroid exposure while maintaining disease control. SCOPE: Among corticosteroid-sparing agents are cytotoxic drugs and interferon-alpha; anti-interleukin-5 (IL-5) monoclonal antibodies are also currently under investigation for the treatment of HES. This manuscript reviews the available treatments for HES and the range of side-effects associated with long-term corticosteroid use, and then focuses on the anti-IL-5 monoclonal antibodies, mepolizumab and reslizumab. Of these, only mepolizumab has been studied in a randomized, placebo-controlled trial. Literature search methodology utilized www.pubmed.gov and www.clinicaltrials.gov with search terms including hypereosinophilic syndrome and corticosteroid side-effects coupled with search terms including eosinophils, mepolizumab and reslizumab through March 2010. FINDINGS: Three case studies are presented that demonstrate the limitations of corticosteroid therapy in terms of tolerability and quality of life, and the subsequent use of mepolizumab as a corticosteroid-sparing agent in these individuals. CONCLUSION: Targeted eosinophil-directed therapy with an anti-IL-5 neutralizing monoclonal antibody reduced the need for corticosteroids in these three HES patients without disease exacerbations.

FIP1L1-PDGFRalpha D842V, a novel panresistant mutant, emerging after treatment of FIP1L1-PDGFRalpha T674I eosinophilic leukemia with single agent sorafenib.

Chronic eosinophilic leukemia (CEL) is a rare myeloproliferative neoplasm characterized by the FIP1L1-PDGFRA fusion gene, variant PDGFRA fusions or other genetic lesions. Most FIP1L1-PDGFRA positive patients enjoy durable and complete molecular responses to low-dose imatinib (Glivec/Gleevec). However, resistance mediated by a T674I mutation in the ATP-binding pocket of PDGFRA has been reported in advanced disease, and sorafenib, a potent inhibitor of RAF-1, B-RAF, VEGFR and PDGFR, is active against this mutant in vitro. We describe a case of FIP1L1-PDGFRalpha T674I CEL in blast crisis that responded to sorafenib (Nexavar). However, this clinical response was short-lived because of the rapid emergence of a FIP1L1-PDGFRalpha D842V mutant. An N-Nitroso-N-ethylurea-mutagenesis screen indeed identified this mutant as a major sorafenib-resistant mutant. In vitro, the novel FIP1L1-PDGFRalpha D842V mutant is highly resistant to sorafenib, imatinib, dasatinib (Sprycell) and PKC412 (Midostaurin). Thus, sorafenib is clinically active in imatinib-resistant FIP1L1-PDGFRalpha T674I CEL, but the rapid emergence of other mutants may limit the response duration. The identification of new PDGFR inhibitors will be required to overcome resistance by this D842V mutant.

[What's new in internal medicine?]. / Quoi de neuf en médecine interne.

Brief virologic news included the discovery of the virophage, a unique parasite of the giant mimivirus and the association of HHV-8 infection with a peculiar form of African diabetes. Secondly, this news focused on risk factors for arterial or venous thrombosis and therapy for auto-immune disorders. Only oral estrogen therapy increases the risk of venous thromboembolism in postmenopausal women. Despite significant homocysteine lowering, vitamin supplementation with folic acid, vitamins B6 and B12 did not reduce total cardiovascular events among high-risk patients. Patients with venous thromboembolism have a substantially increased long-term risk of subsequent cardiovascular events while obesity, systemic arterial hypertension, and diabetes are common risk factors for arterial and venous thrombosis. The non fasting ApoB/ApoA1 ratio was superior to any of the cholesterol ratios for estimation of the risk of acute myocardial infection in all ethnic groups. Preventive anticoagulation of in-patients with risk of venous thromboembolism was inadequately prescribed in many hospitals of the world. Subcutaneous administration of methotrexate was more effective than the oral administration at the same dosage in patients suffering from active rheumatoid arthritis. Hydroxychloroquine directly reduces the binding of antiphospholipid antibody-beta2-glycoprotein I complexes to phospholipid bilayers. Anti-IL-5 and anti-IL-6 antibodies were effective for the treatment of respectively hypereosinophilic syndrome and rheumatoid arthritis. The efficacy of proteasome inhibitors and mesenchymal stems cells have been demonstrated in respectively two mouse strains with lupus-like disease and steroid-resistant severe acute graft-versus-host disease. These treatments may be useful for auto-immune disorders if their long term toxicity is acceptable. In conclusion, subcutaneous injections of physiological saline, used as placebo in two different trials, enhanced in vitro activation of immunocompetent cells in healthy individuals.

Approach to the therapy of hypereosinophilic syndromes.

With the introduction of new diagnostic methods and treatment modalities, it has become increasingly clear that hypereosinophilic syndromes (HES) are a heterogeneous group of disorders for which a single approach to treatment is insufficient. This article discusses current treatment modalities for myeloproliferative HES, idiopathic HES, and lymphocytic-variant HES.

The novel tyrosine kinase inhibitor EXEL-0862 induces apoptosis in human FIP1L1-PDGFR-alpha-expressing cells through caspase-3-mediated cleavage of Mcl-1.

The FIP1-like-1 (FIP1L1)-platelet-derived growth factor receptor-alpha (FIP1L1-PDGFR-alpha) fusion kinase causes hypereosinophilic syndrome (HES) in a defined subset of patients. Imatinib mesylate is a potent inhibitor of ABL but also of PDGFR-alpha, and has been associated with durable hematologic responses in patients with HES. However, development of mutations in the tyrosine kinase domain may hamper the activity of tyrosine kinase inhibitors (TKIs), which suggests that novel agents are warranted to prevent or overcome resistance. We evaluated the efficacy of the novel TKI EXEL-0862 in FIP1L1-PDGFR-alpha-expressing cell lines and in cells from a patient with HES harboring the FIP1L1-PDGFR-alpha gene. EXEL-0862 inhibited the proliferation of EOL-1 and imatinib-resistant T674I FIP1L1-PDGFR-alpha-expressing cells and resulted in potent inhibition of the phosphorylation of PDGFR-alpha and downstream proteins STAT3 and Erk1/2, both in vitro and ex vivo. Moreover, EXEL-0862 induced apoptotic death in EOL-1 cells and imatinib-resistant T674I FIP1L1-PDGFR-alpha-expressing cells, and resulted in significant downregulation of the antiapoptotic protein Mcl-1 through a caspase-dependent mechanism. Our data establish EXEL-0862 as a solid candidate for the targeted treatment of patients with FIP1L1-PDGFR-alpha-positive HES.

Sorafenib is a potent inhibitor of FIP1L1-PDGFRalpha and the imatinib-resistant FIP1L1-PDGFRalpha T674I mutant.

The FIP1L1-PDGFRA oncogene is a common cause of chronic eosinophilic leukemia (CEL), and encodes an activated tyrosine kinase that is inhibited by imatinib. FIP1L1-PDGFRA-positive patients with CEL respond to low-dose imatinib therapy, but resistance due to acquired T674I mutation has been observed. We report here the identification of sorafenib as a potent inhibitor of the FIP1 like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRalpha) (T674I) mutant. Sorafenib inhibited the proliferation of FIP1L1-PDGFRalpha and FIP1L1-PDGFRalpha(T674I)-transformed Ba/F3 cells and induced apoptosis of the EOL-1 cell line at a low nanomolar concentration. Western blot analysis confirmed that these effects were due to a direct effect on FIP1L1-PDGFRalpha and FIP1L1-PDGFRalpha(T674I). Sorafenib was recently approved for the treatment of renal cell carcinoma. Our data suggest that low doses of sorafenib could be efficient for the treatment of FIP1L1-PDGFRA-positive CEL and could be used to overcome resistance to imatinib associated with the T674I mutation.

Interferon-alpha treatment of six patients with the idiopathic hypereosinophilic syndrome.

OBJECTIVE: To examine the response to interferon-alpha 2B therapy in six patients with the idiopathic hypereosinophilic syndrome. DESIGN: Prospective cohort study. SETTING: Tertiary referral center, university hospital inpatient and outpatient clinics, and offices of private practice physicians. PATIENTS: Six patients satisfying the criteria for the hypereosinophilic syndrome, five of whom were resistant to or intolerant of conventional treatment. INTERVENTION: Individualized dosages of interferon-alpha based on clinical response and side effects. MEASUREMENTS: Measurements of eosinophilia (peripheral and bone marrow counts), levels of serum eosinophil major basic protein, doses of glucocorticoid and cytotoxic medications, and transfusion requirements. RESULTS: Various dosages of interferon-alpha from 1.5 MU/d to 8 MU/d decreased the total eosinophil count to less than 1000/mm3 in five of six patients. All patients were able to taper and discontinue prednisone and hydroxyurea. Both patients with incapacitating mucosal ulcers had resolution and no recurrence of these previously resistant lesions. Interferon-alpha was generally well tolerated except for dose-limiting side effects, including thrombocytopenia in one patient and in a second patient, temporary worsening of mucosal lesions and constitutional symptoms. CONCLUSIONS: Interferon-alpha is a valuable agent for patients with the hypereosinophilic syndrome who are resistant to or intolerant of conventional therapy and for patients with this syndrome who have incapacitating mucosal ulcers.

Hypereosinophilic syndrome associated with HIV infection. Military Medical Consortium for Applied Retroviral Research.

A hypereosinophilic syndrome associated with dermatitis has been observed rarely in association with HIV infection. We describe the case of a young man with AIDS who came to us with a diffuse cutaneous eruption, fever, angioedema, eosinophilia, and a mildly elevated serum IgE level. No allergic or infectious cause of this illness could be determined, and the patient was treated with corticosteroids and PUVA therapy, resulting in complete resolution of the dermatitis and associated findings. In this case, there were clinical and histopathologic similarities to the idiopathic hypereosinophilic syndrome and to acute graft-versus-host disease. The serum level of the cytokine interleukin-5 (IL-5), which is associated with eosinophil production, was found to be mildly elevated during the peak of the eruption, while samples drawn previously and subsequently were not. Although it appears that the syndrome we describe is associated with the measurably elevated level of IL-5, further investigation is required to determine whether there is a cause and effect relationship between IL-5 and this entity. A brief review of the literature concerning eosinophils and HIV infection is also presented in the context of this case.