Allen, Carl E.

Abstract Endocrinopathies are frequently the initial presentation of histiocytic neoplasms, which are rare hematologic disorders affecting multiple organ systems. Langerhans cell histiocytosis and Erdheim–Chester disease are 2 such disorders known to infiltrate the hypothalamus and/or pituitary gland, leading to arginine vasopressin deficiency (AVP-D) and anterior pituitary dysfunction (APD) in 20% to 30% of cases, often as the first manifestation. Conversely, histiocytic disorders account for a notable proportion (10-15%) of all pituitary stalk lesions. The diagnosis of histiocytoses is often delayed in such cases due to the nonspecific presentation of endocrinopathies and pituitary involvement. Consequently, endocrinologists are at the frontline and uniquely positioned to achieve early diagnosis by recognizing the varied nonendocrine features of these disorders. This article provides an overview of the endocrine manifestations of histiocytic disorders and presents a simplified algorithm to guide the diagnostic workup in cases presenting with “idiopathic” AVP-D or APD. Such cases should be evaluated for histiocytic neoplasms with additional imaging studies and biopsies of suspected disease sites. If no disease site beyond the pituitary is identified, the risks and benefits of a pituitary stalk lesion biopsy must be carefully considered. While treatments of histiocytic neoplasms are highly efficacious, endocrinopathies are considered permanent and require long-term hormone replacement. It remains unclear whether early diagnosis and novel targeted therapies can reverse these endocrine disorders. Therefore, the role of the endocrinologist role is critical in the diagnosis and management of these rare diseases.

Introduction: ELA026 is a first-in-class human monoclonal antibody directed against signal regulatory protein (SIRP)α/β1/γ and is under clinical investigation in secondary hemophagocytic lymphohistiocytosis (sHLH). sHLH is a life-threatening hyperinflammatory condition caused by failure to terminate the activation and proliferation of natural killer (NK), T cells and macrophages after an initial immune response. There are no approved therapies for sHLH. With a mortality rate of approximately 50% at 2 months (Lionel et al. 2023), malignancy-associated HLH (mHLH) is the deadliest subtype of sHLH. Cytotoxic, multi-agent chemotherapy (including etoposide) does not address the poor prognosis associated with mHLH (Xie et al. 2013). Directly targeting the pathogenic SIRP(+) myeloid cells and T lymphocytes represents a novel approach to resolving this severe hyperinflammatory condition. Methods: This is an open-label, single-arm, Phase 1b global multicenter study (NCT05416307) evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of ELA026 in adult and pediatric patients with newly diagnosed and previously treated sHLH. The study is expanding enrollment to evaluate a fixed-dose regimen consisting of a priming phase of 0.1 mg/kg Day 1 and 0.3 mg/kg Days 2-4, followed by a maintenance phase of 0.5 mg/kg twice weekly beginning on Day 8. ELA026 is administered intravenously, with the option to transition to subcutaneous administration upon hospital discharge. The treatment period is 12 weeks with the option to extend in patients deriving ongoing clinical benefits. Enrollment in this cohort is restricted to frontline settings based on the experience that relapsed/refractory sHLH patients exhibited poor survival even with HLH disease control and died from complications related to severe baseline comorbidities. Response is evaluated using a modified HLH-2004 criteria (Locatelli et al. 2020) and survival is calculated from the time of HLH diagnosis. All patients receive dexamethasone as background therapy and premedication initially. Patients with mHLH may also receive cancer-directed therapies concurrently. Primary pharmacodynamic (PD) effects (monocyte and lymphocyte reduction) and secondary PD effects (C-reactive protein [CRP], ferritin, and sCD25 reduction) were best evaluated and attributed to ELA026 during windows of treatment without concurrent chemotherapy effects. Results: As of July 15, 2024, 12 treatment-naïve mHLH patients have enrolled in all cohorts of the study, with a median age of 47 years (range 21-78). The following malignancies were represented: 7 T-cell lymphoma, 2 DLBCL, 1 AML, 1 Hodgkin lymphoma, and 1 T-cell ALL. In this group, response rate was 100% with 2 mCR and 9 PR by Week 4 and survival was 88% at 2 months (7/8; 4 patients are alive and have not reached 2 months on study). Median survival has not been reached; median follow-up is 2.3 months (range 0.1-15.9 months). In terms of PD effects, monocyte and lymphocyte reduction generally occurred following the first priming dose and ferritin and CRP were reduced by an average of 40% and 50% by Day 6, respectively, for patients with windows of ELA026 treatment without concurrent chemotherapy effects. Study-wide (all patients dosed), treatment-related infusion reactions (~20%) and cytopenias (~30%) were generally manageable with supportive care and dosing modifications. One serious adverse event, a grade 4 infusion reaction, was assessed as related in a relapsed/refractory mHLH patient with acute liver failure and poor hemodynamic reserve. Infection risks are expected for this patient population, which were mitigated with growth factor support and antimicrobial prophylaxis. No deaths were related to study drug. Updated study results will be provided at the 2024 ASH meeting in San Diego. Conclusion: Data suggest ELA026 is well-tolerated to date in sHLH patients and results in a 100% response rate and improved 2-month survival in treatment-naïve mHLH patients. The study is enrolling in an expanded cohort to further assess efficacy in this patient population.

Abstract Defining prognostic variables in T-lymphoblastic lymphoma (T-LL) remains a challenge. AALL1231 was a Children’s Oncology Group phase 3 clinical trial for newly diagnosed patients with T acute lymphoblastic leukemia or T-LL, randomizing children and young adults to a modified augmented Berlin-Frankfurt-Münster backbone to receive standard therapy (arm A) or with addition of bortezomib (arm B). Optional bone marrow samples to assess minimal residual disease (MRD) at the end of induction (EOI) were collected in T-LL analyzed to assess the correlation of MRD at the EOI to event-free survival (EFS). Eighty-six (41%) of the 209 patients with T-LL accrued to this trial submitted samples for MRD assessment. Patients with MRD <0.1% (n = 75) at EOI had a superior 4-year EFS vs those with MRD ≥0.1% (n = 11) (89.0% ± 4.4% vs 63.6% ± 17.2%; P = .025). Overall survival did not significantly differ between the 2 groups. Cox regression for EFS using arm A as a reference demonstrated that MRD EOI ≥0.1% was associated with a greater risk of inferior outcome (hazard ratio, 3.73; 95% confidence interval, 1.12-12.40; P = .032), which was independent of treatment arm assignment. Consideration to incorporate MRD at EOI into future trials will help establish its value in defining risk groups. CT# NCT02112916.

Abstract With the introduction of large-scale molecular profiling methods and high-throughput sequencing technologies, the genomic features of most lymphoid neoplasms have been characterized at an unprecedented scale. Although the principles for the classification and diagnosis of these disorders, founded on a multidimensional definition of disease entities, have been consolidated over the past 25 years, novel genomic data have markedly enhanced our understanding of lymphomagenesis and enriched the description of disease entities at the molecular level. Yet, the current diagnosis of lymphoid tumors is largely based on morphological assessment and immunophenotyping, with only few entities being defined by genomic criteria. This paper, which accompanies the International Consensus Classification of mature lymphoid neoplasms, will address how established assays and newly developed technologies for molecular testing already complement clinical diagnoses and provide a novel lens on disease classification. More specifically, their contributions to diagnosis refinement, risk stratification, and therapy prediction will be considered for the main categories of lymphoid neoplasms. The potential of whole-genome sequencing, circulating tumor DNA analyses, single-cell analyses, and epigenetic profiling will be discussed because these will likely become important future tools for implementing precision medicine approaches in clinical decision making for patients with lymphoid malignancies.

PURPOSE The NCI-COG Pediatric MATCH trial assigns patients age 1-21 years with relapsed or refractory solid tumors, lymphomas, and histiocytic disorders to phase II studies of molecularly targeted therapies on the basis of detection of predefined genetic alterations. Patients with tumors harboring mutations or fusions driving activation of the mitogen-activated protein kinase (MAPK) pathway were treated with the MEK inhibitor selumetinib. METHODS Patients received selumetinib twice daily for 28-day cycles until disease progression or intolerable toxicity. The primary end point was objective response rate; secondary end points included progression-free survival and tolerability of selumetinib. RESULTS Twenty patients (median age: 14 years) were treated. All were evaluable for response and toxicities. The most frequent diagnoses were high-grade glioma (HGG; n = 7) and rhabdomyosarcoma (n = 7). Twenty-one actionable mutations were detected: hotspot mutations in KRAS (n = 8), NRAS (n = 3), and HRAS (n = 1), inactivating mutations in NF1 (n = 7), and BRAF V600E (n = 2). No objective responses were observed. Three patients had a best response of stable disease including two patients with HGG ( NF1 mutation, six cycles; KRAS mutation, 12 cycles). Six-month progression-free survival was 15% (95% CI, 4 to 34). Five patients (25%) experienced a grade 3 or higher adverse event that was possibly or probably attributable to study drug. CONCLUSION A national histology-agnostic molecular screening strategy was effective at identifying children and young adults eligible for treatment with selumetinib in the first Pediatric MATCH treatment arm to be completed. MEK inhibitors have demonstrated promising responses in some pediatric tumors (eg, low-grade glioma and plexiform neurofibroma). However, selumetinib in this cohort with treatment-refractory tumors harboring MAPK alterations demonstrated limited efficacy, indicating that pathway mutation status alone is insufficient to predict response to selumetinib monotherapy for pediatric cancers.

10008 Background: The NCI-Children’s Oncology Group (COG) Pediatric Molecular Analysis for Therapy Choice (MATCH) trial assigns patients age 1 to 21 years with relapsed or refractory solid tumors, lymphomas, and histiocytic disorders to phase 2 treatment arms of molecularly-targeted therapies based on genetic alterations detected in their tumor. Arm E evaluated the MEK inhibitor selumetinib (ARRY-142886) in patients whose tumors harbored activating alterations in the MAPK pathway ( ARAF, BRAF, HRAS, KRAS, NRAS, MAP2K1, GNA11, GNAQ hotspot mutations; NF1 inactivating mutations; BRAF fusions). Methods: Patients received selumetinib 25 mg/m2/dose (max 75 mg/dose) PO BID for 28-day cycles until disease progression or intolerable toxicity with response assessments obtained every 2-3 cycles. The primary endpoint was objective response rate (ORR); secondary endpoints included progression-free survival (PFS). Patients with low grade glioma were excluded. Results: A total of 21 patients (median age 14 years; range 5-21) were enrolled between 10/2017 and 8/2019, with 20 patients evaluable for response. Diagnoses were high grade glioma (HGG; n = 8), rhabdomyosarcoma (n = 7), adenocarcinoma (n = 2), and one each of MPNST, endodermal sinus/yolk sac tumor, plexiform neurofibroma (PN), and neuroblastoma. MAPK pathway alterations detected consisted of inactivating NF1 mutations (n = 8), hotspot mutations in KRAS (n = 8), NRAS (n = 3), and HRAS (n = 1), and BRAF V600E (n = 2). No objective responses were observed. Three patients had a best response of stable disease (HGG with NF1 mutation, 6 cycles; HGG with KRAS mutation, 12 cycles; PN with NF1 mutation, 13 cycles prior to removal for dose-limiting toxicity). Six-month PFS was 15% (95% CI: 4%, 34%). Adverse events that were deemed possibly, probably, or definitely attributable to study drug included one case each of grade 3 uveitis, lymphopenia, and thromboembolic event; one grade 4 CPK elevation; and one grade 5 thromboembolic event. Conclusions: Selumetinib did not result in tumor regression in this cohort of children and young adults with treatment-refractory tumors with activating MAPK pathway alterations. Of note, two patients with HGG initially had stable disease, but ultimately progressed after 6 and 12 cycles, respectively. Selumetinib has previously demonstrated activity in low grade glioma and PN and is now FDA-approved for PN. The results of our study indicate that MAPK pathway mutation status alone is insufficient to predict response to selumetinib monotherapy. It is likely that selumetinib and other MEK inhibitors will require combination with targeted or cytotoxic agents for optimal efficacy in children with persistent or progressive cancers after front-line chemotherapy. Clinical trial information: NCT03213691. Clinical trial information: NCT03155620.

Abstract Background Langerhans cell histiocytosis (LCH) is a heterogeneous disease whose myriad manifestations result from accumulation of Langerhans cells in a variety of organs most commonly including skin, bone, central nervous system, liver, lymph nodes, and bone marrow. The disease can affect people of any age. Treatment is primarily driven by disease extent and organ involvement and can range from focused radiation or surgery to multi-agent chemotherapy. There is a relatively high recurrence rate following complete remissions with conventional chemotherapy. In the first-time-in-human (FTIH) study of the oral pan-AKT inhibitor afuresertib (GSK2110183), in patients with hematologic malignancies, a patient with refractory multi-system LCH experienced a prolonged period (> 3 years) of clinical benefit on 125mg oral once daily afuresertib. This observation led to the evaluation of the use of afuresertib in patients with LCH. Methods This single-arm, open-label trial was designed to evaluate the efficacy and safety of afuresertib, administered at 125 mg once daily, in adults and adolescents with relapsed/refractory LCH and adults with treatment-naïve LCH. Secondary objectives included pharmacokinetics. Diagnosis of LCH was confirmed by pathology review of archival tissue. The Histiocyte Society criteria were used for response evaluation at three and six months with safety and pharmacokinetic assessments performed at pre-specified intervals. BRAF status from archival tissue was evaluated by Sanger sequencing. Results 17 patients (16 adults, 10 females) were enrolled; median age was 38 years (15-75). 3/17 patients had isolated pulmonary disease, 1/17 had single-system multifocal-bone disease, 1/17 had single-system skin disease, and 12/17 had multi-system disease. Seven patients were treatment-naïve; 10 had relapsed/refractory disease, including the one adolescent. The most frequent (>20% of patients) adverse events (AEs), regardless of causality, were nausea (59%), fatigue (59%), upper respiratory infection (47%), diarrhea (47%), dyspepsia (35%), bone pain (39%), asthenia (24%), memory impairment (24%), decreased appetite (24%) and vomiting (24%). Most AEs were Grade 1 or 2 in severity; no Grade 4 AEs were reported and no Grade 3 AEs occurring in more than 1 subject were reported. 6/17 (35%) had afuresertib dose modifications (interruption or reduction). Afuresertib plasma concentrations in the adult patients were similar to values seen in adult patients with other hematologic malignancies in the FTIH study. Following a single dose, the concentration-time profile in the adolescent patient was similar to adults in the FTIH study (Tmax = 3h: Cmax 229 ng/ml: AUC24 = 3893 ng*h/mL). 15 patients had archival tissues collected for BRAF testing; 13 had DNA suitable for analysis. 2/13 was BRAF V600E mutant and 11/13 were BRAF wild type. Upon evaluation of the all-treated patient population, 5/17 (29%) patients were reported as better at the three and/or six month disease assessment. Among the 5 responders, three were treatment-naïve and two had relapsed/refractory disease. The median duration on study for all patients was 214 (44-426) days. For the 5 patients who responded, the median duration on study was 372 (255-426) days. Conclusion The pharmacokinetic and safety profile of afuresertib in patients with LCH was consistent with that observed in patients with other hematologic malignancies evaluated in the FTIH study. Afuresertib was active in patients with both treatment-naïve and relapsed/refractory disease. Additional evaluation, including molecular profiling, may be warranted alone or in combination with BRAF inhibitors or established therapies for LCH to determine the optimal population of patients with LCH who might benefit from afuresertib Disclosures: Vassallo: GlaxoSmithKline: Research Funding. Oliff:GlaxoSmithKline: Employment. Morris:GlaxoSMithKline: Employment. Reedy:GlaxoSmithKline: Employment. Portnoy:GlaxoSmithKline: Stock, prior employee Other. Smith:GlaxoSmithKline: Employment, Equity Ownership. Noble:GlaxoSmithKline: Employment, stock Other. Murnane:GlaxoSmithKline: Employment, stock Other. Szabo:GlaxoSmithKline: Employment. Heaney:Novartis: Research Funding; Sanofi-Aventis: Consultancy, Research Funding; Onconova: Research Funding; Incyte: Consultancy, Research Funding.

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune activation and dysregulation resulting in extreme and often life‐threatening inflammation. HLH has been well recognized in pediatric populations, and most current diagnostic and therapeutic guidelines are based on pediatric HLH. Recently there has been recognition of HLH in adults, especially secondary to immune deregulation by an underlying rheumatologic, infectious, or malignant condition. This review is focused on malignancy‐associated HLH (M‐HLH), in which possible mechanisms of pathogenesis include severe inflammation, persistent antigen stimulation by the tumor cells, and loss of immune homeostasis because of chemotherapy, hematopoietic stem cell transplantation, or infection. Previously considered rare, M‐HLH may occur in up to 1% of patients with hematologic malignancies. M‐HLH is often missed or diagnosed late in most published studies, and it has been associated with a poor median survival of less than 2 months. Identification of the clinical and laboratory features specific to M‐HLH in adults may allow early detection, consultation with HLH experts, and intervention. Improved management of adult M‐HLH with optimal combinations of T‐lympholytic and immunosuppressive agents and the incorporation of novel agents based on the pediatric experience hopefully will improve outcomes in adults with M‐HLH. Cancer 2017;123:3229‐40. © 2017 American Cancer Society.

AbstractBackgroundLangerhans cell histiocytosis (LCH) is a clonal neoplasm characterized by widely varied clinical presentations, including multisystem involvement and systemic inflammatory symptoms. The AKT pathway is relevant to survival and proliferation of dendritic cells, and is also often upregulated in hematopoietic malignancies. A clinical response in an adult patient with LCH participating in the first‐in‐human trial of afuresertib prompted this prospective trial.ProcedureThe population in the current study included treatment‐naïve (n = 7) and recurrent/refractory patients with LCH (n = 10), who received oral afuresertib (125 mg). The majority of patients were treated for > 24 weeks, with four patients receiving treatment for > 48 weeks.ResultsPharmacokinetic analysis showed similar exposures in previously reported patients with other hematologic malignancies. Primary drug‐related toxicities included Grade 1/2 nausea, diarrhea, dyspepsia, and vomiting. Grade 3 toxicities included fatigue, diarrhea, and pain (one of each). Another severe adverse event involved soft tissue necrosis. The overall response rate in evaluable subjects was 33% in treatment‐naïve patients and 28% in patients with recurrent/refractory disease, which did not meet the predefined Bayesian criteria for efficacy.ConclusionAfuresertib has clinical activity in some patients with newly diagnosed and advanced LCH.