Lenalidomide proved effective in multisystem Langerhans cell histiocytosis

International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults

Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.

Histiocytic Neoplasms, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Histiocytic neoplasms are rare hematologic disorders accounting for less than 1% of cancers of the soft tissue and lymph nodes. Clinical presentation and prognosis of these disorders can be highly variable, leading to challenges for diagnosis and optimal management of these patients. Treatment often consists of systemic therapy, and recent studies support use of targeted therapies for patients with these disorders. Observation ("watch and wait") may be sufficient for select patients with mild disease. These NCCN Guidelines for Histiocytic Neoplasms include recommendations for diagnosis and treatment of adults with the most common histiocytic disorders: Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease.

Adult Langerhans cell histiocytosis and immunomodulatory drugs: Review and analysis of thirty-four case reports

Langerhans cell histiocytosis (LCH) is a rare neoplastic disease in dendritic cells. LCH is classified as either a single-system (SS) or multisystem (MS) disease. There is not a standard first-line treatment for LCH in adults. We analyzed the efficacy and safety of immunomodulatory drugs (IMiDs) by searching PubMed/MEDLINE for case reports previously published. The clinical response (nonactive disease or active disease that regressed) was 94% in SS and 53% in MS. IMiDs should only be considered for adults with cutaneous SS involvement; in MS, they should be used only for patients not eligible for more aggressive treatments.

Successful Treatment of Refractory Langerhans Cell Histiocytosis of the Choroid Plexus in a Child With Pulse Dexamethasone and Lenalidomide

Refractory/relapsed Langerhans cell histiocytosis (LCH) has a difficult course with a guarded prognosis. Salvage treatments available are both expensive and highly toxic. On the basis of the pathophysiology of LCH, we used a novel protocol including pulse dexamethasone and lenalidomide in a child with refractory LCH involving the choroid plexus, which resulted in durable remission with minimal toxicity. The protocol was extrapolated from the FIRST trial for patients with multiple myeloma. We present the clinical course, treatment protocol, and outcome in this child, who is at present disease free and in remission 18 months posttreatment.

Excellent remission rates with limited toxicity in relapsed/refractory Langerhans cell histiocytosis with pulse dexamethasone and lenalidomide in children

Refractory/relapsed Langerhans cell histiocytosis (LCH) has a difficult course with a guarded prognosis. We used a novel protocol including six cycles of pulse dexamethasone and lenalidomide in four children with LCH refractory to first-line agents and courses of cladribine and cytarabine or single-agent cladribine. All four children completed the protocol without any significant adverse effects and remain in complete and durable remission 15-18 months posttreatment. The novel protocol we propose for relapsed/refractory LCH is cost-effective and outpatient-based with durable remission and minimal toxicity. This is particularly suited for resource-limited settings.

New insights into the molecular pathogenesis of langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder characterized by an accumulation of cells sharing the major phenotypic features of cutaneous Langerhans cells. Given its variable clinical evolution, ranging from self-limiting lesions to multisystemic forms with a poor prognosis, in the last decades it has been debated whether LCH might not have a neoplastic rather than an inflammatory nature. However, although the fundamental events underlying the pathogenesis of LCH are still elusive, recent advances have strikingly improved our understanding of the disease. In particular, the identification of multiple interplays between LCH cells and their tumor microenvironment, along with the recognition of the lesional cytokine storm as a key determinant of LCH progression, has substantiated new opportunities for devising targeted therapeutic approaches. Strikingly, the detection of the rapidly accelerated fibrosarcoma isoform B(V600E) gain-of-function mutation as a genetic alteration recurring in more than 50% of patients has fueled the paradoxical picture of LCH as a tumor of the antigen-presenting cells that can evade rejection by the immune system. Thus, new evidence regarding the ontogeny of LCH cells, as well as a better understanding of the putative immune system frustrating strategy in LCH, may help to define the precise pathogenesis.

Salvage lenalidomide in four rare oncological diseases

In rare disorders, there are often no standard therapy recommendations. Patients with refractory disease may require novel experimental approaches. Applied as second- up to fourth-line treatment, lenalidomide (10–25 mg perorally on days 1–21 in a 28-day cycle) was used in our cohort of four adult patients with aggressive, multisystem and relapsing diseases. Complete and long-lasting remissions (more than 1 year, no maintenance therapy) were achieved in patients with Langerhans cell histiocytosis (11 cycles, combination with dexamethasone and etoposide, consolidated by allogeneic blood stem cell transplant) and plasma-cell Castleman disease (15 cycles, monotherapy). Mixed response with complete disappearance of brain infiltrates was reached in Erdheim-Chester disease (6 cycles, monotherapy) and gastrointestinal bleeding was well controlled in multiple angiomatosis (9 cycles, combination with thalidomide). For disease activity evaluation each patient underwent fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography scan imaging, which was complemented by clinical and laboratory investigations.

Cladribine (2-chlorodeoxyadenosine) in frontline chemotherapy for adult Langerhans cell histiocytosis: A single-center study of seven cases

BACKGROUND

Adult Langerhans cell histiocytosis is a rare disorder with diverse clinical manifestations and inconsistent treatment outcomes to conventional therapeutic regimens. Cladribine (2-chlorodeoxyadenosine) repeatedly proved effective in cases of relapsed multifocal and multisystem disease forms. In this retrospective study we present an analysis of cladribine in frontline systemic therapy.

MATERIAL AND METHODS

A cohort of seven male patients with biopsy proved multisystem (six cases) and multifocal (one case) Langerhans cell histiocytosis received cladribine at a dose of 5 mg/m(2) subcutaneously (five cases) or by two-hour intravenous infusion (two cases) over five consecutive days, every four weeks for a median of four courses (range 4-6). The treatment was enhanced with cyclophosphamide (300 mg intravenously on days 1-5 in cycles 4-6) and corticoids (dexamethasone 24 mg orally or methylprednisolone 250 mg intravenously on days 1-5 in cycles 4-6) in two patients, with radiotherapy (20 Gy on skin or bone lesions) in three patients and with photochemotherapy (psoralen plus ultraviolet A light, PUVA) on skin lesions in one patient.

RESULTS

All patients achieved clinically relevant treatment response confirmed by positron emission tomography (PET). Durable complete remissions were maintained in six patients (86%), including two patients with hypophysis involvement, with the median follow-up of 37 months (range 15-94; 49.8 ± 35.2 [ 6 ]). One patient had an aggressive, early relapsing disease requiring further treatment lines. The treatment-related toxicities consisted of transient bone marrow suppression affecting the leukocytes predominantly. Grade 3 lymphopenia occurred in five patients (71%) and grade 3 neutropenia in one patient (14%).

CONCLUSION

Cladribine, both as a single agent as well as in combination with an alkylating cytostatic and corticoids, represents an effective treatment option with favorable toxicity profile for adult patients with multisystem or aggressive multifocal form of Langerhans cell histiocytosis.