Real-world treatment patterns and outcomes in patients with primary hemophagocytic lymphohistiocytosis treated with emapalumab

ABSTRACT

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening, hyperinflammatory syndrome. Emapalumab, a fully human monoclonal antibody that neutralizes the proinflammatory cytokine interferon gamma, is approved in the United States to treat primary HLH (pHLH) in patients with refractory, recurrent, or progressive disease, or intolerance with conventional HLH treatments. REAL-HLH, a retrospective study, conducted across 33 US hospitals, evaluated real-world treatment patterns and outcomes in patients treated with ≥1 dose of emapalumab between 20 November 2018 and 31 October 2021. In total, 46 patients met the pHLH classification criteria. Median age at diagnosis was 1.0 year (range, 0.3-21.0). Emapalumab was initiated for treating refractory (19/46), recurrent (14/46), or progressive (7/46) pHLH. At initiation, 15 of 46 patients were in the intensive care unit, and 35 of 46 had received prior HLH-related therapies. Emapalumab treatment resulted in normalization of key laboratory parameters, including chemokine ligand 9 (24/33, 72.7%), ferritin (20/45, 44.4%), fibrinogen (37/38, 97.4%), platelets (39/46, 84.8%), and absolute neutrophil count (40/45, 88.9%). Forty-two (91.3%) patients were considered eligible for transplant. Pretransplant survival was 38 of 42 (90.5%). Thirty-one (73.8%) transplant-eligible patients proceeded to transplant, and 23 of 31 (74.2%) of those who received transplant were alive at the end of the follow-up period. Twelve-month survival probability from emapalumab initiation for the entire cohort (N = 46) was 73.1%. There were no discontinuations because of adverse events. In conclusion, results from the REAL-HLH study, which describes treatment patterns, effectiveness, and outcomes in patients with pHLH treated with emapalumab in real-world settings, are consistent with the emapalumab pivotal phase 2/3 pHLH trial.

The effect of mind-body intervention on lymphocyte doubling time and treatment free survival in treatment-naïve chronic lymphocytic leukemia patients

INTRODUCTION

Mind-Body Intervention (MBI) serves as supportive aid in oncology. We hypothesized that MBI could impact the progression of Chronic Lymphocytic Leukemia (CLL) in the 'watch and wait' (w&w) phase.

METHODS

MBI was utilized in a non-randomized prospective controlled study between 02/2020-02/2022 in 76 treatment-naïve CLL patients in the w&w phase (37 intervention and 39 control patients). The primary and secondary endpoints were prolongation of Lymphocyte Doubling Time (LDT) and treatment-free survival (TFS). The prolongation of LDT was compared at 0, 180, 360, and 540 days using paired t-tests. TFS was compared between intervention and control groups using the log-rank test. Cox proportional hazards models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for TFS in the intervention group compared to the control, stratified by the study covariates.

RESULTS

MBI prolonged LDT at all time points, including at day 360 (Median of 2.47 years; CI 1.05-3.9; p= 0.001). TFS at 18 months was longer in the intervention group compared to the control group (HR 0.23; CI 0.06-0.79, p=0.01).

CONCLUSIONS

MBI was associated with prolonged LDT and TFS in patients with CLL in the w&w phase. These results provide a basis for a larger randomized-control trial.

Early response markers predict survival after etoposide-based therapy of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that is most commonly treated with etoposide and dexamethasone. This standard of care therapy has improved survival, but ∼15% of patients still die in the first months after diagnosis, and poor responses prompting salvage therapy are frequent. Thus, identifying patients at risk promptly is likely to improve outcomes. We conducted a multi-institutional, retrospective study of pediatric and young adults treated per HLH-94 or HLH-2004 from 2010 to 2019 to identify patients at risk for early mortality. Biweekly data during the first 100 days of treatment were analyzed using receiver operating curves to define optimal prognostic indicators and their thresholds. The primary end point was survival to bone marrow transplant (BMT) or ∼1 year if no BMT was pursued. Eighty-nine patients met the study inclusion criteria. Pre-BMT mortality was 13% (n = 12), and overall mortality was 27% (n = 24). Laboratory markers measured on day 7 of therapy more efficiently predicted outcomes than did either pretreatment or later assessments. The most potent day 7 unfavorable marker was improvement in soluble CD25 (sCD25) of less than 25% from pretherapy levels. Absolute sCD25 level, platelet count, absolute lymphocyte count, and blood urea nitrogen were also discriminatory markers (area under the curve ≥ 0.7). The presence of ≥3 of these unfavorable markers was strongly associated with pre-BMT mortality (accuracy, 0.93). Thus, serial monitoring of sCD25 and assessment of other early (day 7) response markers optimally predicts prognosis with etoposide-based therapy and may indicate the need for earlier use of alternative, response-adapted therapeutic strategies for HLH.

Inpatient recognition and management of HLH

Hemophagocytic lymphohistiocytosis (HLH) is one of the life-threatening emergencies that a hematologist may be called upon to diagnose and manage. It is a hyperinflammatory process that develops in patients with genetic abnormalities, hematologic malignancies, chronic inflammatory states, or infections. The main clinical challenges are recognizing HLH, determining whether the immune response is aberrant or appropriate, and deciding upon therapy. Patients may present with fever, central nervous system symptoms, cytopenias, or elevated liver enzymes. Recognizing HLH is challenging because its features overlap with numerous systemic disorders, thus requiring a high level of suspicion and timely investigations to confirm the diagnosis and detect the underlying trigger. Once HLH is diagnosed, careful consideration of immunosuppressive therapy's potential benefit versus harm is necessary. Such therapy can sometimes be tailored to the underlying trigger. In the acute setting, the competing pressures of completing a thorough diagnostic process (including evaluation for the presence of lymphoma and infection) and the need for expedited treatment must be balanced. During the management of an HLH patient, continuous vigilance for the presence of as-yet unrecognized disease triggers, monitoring response, and identifying emerging complications is critical. This review will discuss the recognition and management of HLH in the inpatient setting.

Alemtuzumab and CXCL9 levels predict likelihood of sustained engraftment after reduced intensity conditioning HCT

Overall survival following reduced intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (HCT) using alemtuzumab, fludarabine, and melphalan is favorable in patients transplanted for inborn errors of immunity (IEI), but RIC is associated with high rates of mixed chimerism (MC) and secondary graft failure (GF). We hypothesized that peri-transplant alemtuzumab levels or specific patterns of inflammation would predict these risks. We assessed samples from BMT CTN 1204 (NCT01998633) to study the impact of alemtuzumab levels and cytokine patterns on MC and impending or established secondary GF (defined as donor chimerism <5% after initial engraftment and/or requirement of cellular intervention). Thirty-three patients with HLH (n=25) and other IEI (n=8) who underwent HCT with T-cell replete grafts were included. Patients with day 0 alemtuzumab levels ≤0.32μg/mL had a markedly lower incidence of MC, 14.3%, versus 90.9% in patients >0.32μg/mL (p=0.008). Impending or established secondary GF was only observed in patients with day 0 alemtuzumab levels >0.32µg/mL (p=0.08). Unexpectedly, patients with impending or established secondary GF had lower CXCL9 levels. The cumulative incidence of impending or established secondary GF in patients with a day +14 CXCL9 level ≤2394pg/mL (day +14 median) was 73.6% versus 0% in patients >2394pg/mL (p=0.002). CXCL9 levels inversely correlated with alemtuzumab levels. These findings support a relationship between alemtuzumab levels, CXCL9 levels, and sustained engraftment. These data suggest a model in which higher levels of alemtuzumab at day 0 deplete donor T-cells, inhibit the graft-versus-marrow reaction (thereby suppressing CXCL9 levels), and adversely impact sustained engraftment in the non-myeloablative HCT setting. Clinical Trial # NCT01998633.

A Case of Chronic Lymphocytic Leukemia Complicated by Hemophagocytic Lymphohistiocytosis: Identifying the Aberrant Immune Response

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that may complicate hematologic malignancies. HLH and malignancies have common clinical features, and HLH diagnostic criteria (HLH-2004/Hscore) were not validated in this specific population. We describe a case of a 72-year-old patient with a history of chronic lymphocytic leukemia stable for over 10 years who presented with fever and cytopenia. After excluding infectious etiologies and the progression of her disease, HLH was diagnosed. The patient was treated with etoposide, dexamethasone, intravenous immunoglobulin, and rituximab. Despite initial clinical improvement, the patient deteriorated and developed pulmonary aspergillosis and CNS involvement that reflected uncontrolled HLH. The patient died 45 days after her presentation. An unusual feature of this case was that HLH was not triggered by infection, disease transformation, or treatment. This case emphasizes the challenges of differentiating the development of overwhelming HLH from other complications associated with hematologic malignancy.

Malignancy-associated haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is an inflammatory syndrome that can occur with cancer (malignancy-associated HLH) or with immune-activating therapies for cancer. Patients with lymphoma appear to be at particularly high risk for malignancy-associated HLH. The familial form of HLH is characterised by uncontrolled activation of macrophages and cytotoxic T cells, which can be identified by genetics or specific immune markers. However, the pathophysiology of malignancy-associated HLH is not well understood, and distinguishing pathological immune activation from the laboratory and clinical abnormalities seen in cancer and cancer treatment is challenging. Emerging diagnostic tools, such as serum cytokine or chemokine concentrations, flow cytometry, and other functional measures, are discussed. Mortality remains high with current approaches. Targeted therapy, including blockade of specific cytokines such as IL-1, IL-6, and IFNγ, and inhibition of the JAK-STAT pathways might improve outcomes for some patients. Finally, we discuss a framework for thinking of malignancy-associated HLH within a larger umbrella concept of cytokine storm syndrome.

An improved index for diagnosis and mortality prediction in malignancy-associated hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening inflammatory syndrome that may complicate hematologic malignancies (HMs). The appropriateness of current criteria for diagnosing HLH in the context of HMs is unknown because they were developed for children with familial HLH (HLH-2004) or derived from adult patient cohorts in which HMs were underrepresented (HScore). Moreover, many features of these criteria may directly reflect the underlying HM rather than an abnormal inflammatory state. To improve and potentially simplify HLH diagnosis in patients with HMs, we studied an international cohort of 225 adult patients with various HMs both with and without HLH and for whom HLH-2004 criteria were available. Classification and regression tree and receiver-operating curve analyses were used to identify the most useful diagnostic and prognostic parameters and to optimize laboratory cutoff values. Combined elevation of soluble CD25 (>3900 U/mL) and ferritin (>1000 ng/mL) best identified HLH-2004-defining features (sensitivity, 84%; specificity, 81%). Moreover, this combination, which we term the optimized HLH inflammatory (OHI) index, was highly predictive of mortality (hazard ratio, 4.3; 95% confidence interval, 3.0-6.2) across diverse HMs. Furthermore, the OHI index identified a large group of patients with high mortality risk who were not defined as having HLH according to HLH-2004/HScore. Finally, the OHI index shows diagnostic and prognostic value when used for routine surveillance of patients with newly diagnosed HMs as well as those with clinically suspected HLH. Thus, we conclude that the OHI index identifies patients with HM and an inflammatory state associated with a high mortality risk and warrants further prospective validation.

T-cell activation profiles distinguish hemophagocytic lymphohistiocytosis and early sepsis

Hemophagocytic lymphohistiocytosis (HLH) is a fatal disorder of immune hyperactivation that has been described as a cytokine storm. Sepsis due to known or suspected infection has also been viewed as a cytokine storm. Although clinical similarities between these syndromes suggest similar immunopathology and may create diagnostic uncertainty, distinguishing them is critical as treatments are widely divergent. We examined T-cell profiles from children with either HLH or sepsis and found that HLH is characterized by acute T-cell activation, in clear contrast to sepsis. Activated T cells in patients with HLH were characterized as CD38high/HLA-DR+ effector cells, with activation of CD8+ T cells being most pronounced. Activated T cells were type 1 polarized, proliferative, and displayed evidence of recent and persistent activation. Circulating activated T cells appeared to be broadly characteristic of HLH, as they were seen in children with and without genetic lesions or identifiable infections and resolved with conventional treatment of HLH. Furthermore, we observed even greater activation and type 1 polarization in tissue-infiltrating T cells, described here for the first time in a series of patients with HLH. Finally, we observed that a threshold of >7% CD38high/HLA-DR+ cells among CD8+ T cells had strong positive and negative predictive value for distinguishing HLH from early sepsis or healthy controls. We conclude that the cytokine storm of HLH is marked by distinctive T-cell activation whereas early sepsis is not, and that these 2 syndromes can be readily distinguished by T-cell phenotypes.

Hemophagocytic lymphohistiocytosis as a harbinger of aggressive lymphoma: a case series

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory syndrome, which can manifest either secondary to a variety of underlying causes, or due to a primary genetic defect. Malignancy is the most common underlying disease in adults with HLH, with lymphomas being the most common malignancy. Lymphoma-associated hemophagocytic syndrome (LAHS) typically follows a rapidly progressive clinical course and is associated with poor prognosis. We herein present four patients with HLH associated with aggressive lymphoma. At initial presentation, the underlying etiology of the HLH was unclear. Two patients were eventually diagnosed with anaplastic large cell lymphoma, while the other two had diffuse large B cell lymphoma. Two of the patients experienced rapid clinical deterioration, one at diagnosis and the other at relapse, and both died prior to diagnosis of lymphoma despite HLH-directed therapy. These cases highlight the need for intensive management in adults with HLH without a clear etiology, especially in cases when lymphoma-associated HLH is suspected. We describe the current pitfalls in diagnosis and treatment of LAHS and discuss possible ways to improve patient management.