Vemurafenib combined with cladribine and cytarabine results in durable remission of pediatric BRAF V600E-positive LCH.

Langerhans cell histiocytosis (LCH) is a disorder with a variety of clinical signs. The most severe forms affect risk organs (RO). The established role of the BRAF V600E mutation in LCH led to a targeted approach. However, targeted therapy cannot cure the disease, and cessation leads to quick relapses. Here, we combined cytosine-arabinoside (Ara-C) and 2'-chlorodeoxyadenosine (2-CdA) with targeted therapy to achieve stable remission. Nineteen children were enrolled in the study: 13 were RO-positive (RO+) and 6 RO-negative (RO-). Five patients received the therapy upfront, whereas the other 14 received it as a second or third line. The protocol starts with 28 days of vemurafenib (20 mg/kg), which is followed by 3 courses of Ara-C and 2-CdA (100 mg/m2 every 12 h, 6 mg/m2 per day, days 1-5) with concomitant vemurafenib therapy. After that, vemurafenib therapy was stopped, and 3 courses of mono 2-CdA followed. All patients rapidly responded to vemurafenib: the median disease activity score decreased from 13 to 2 points in the RO+ group and from 4.5 to 0 points in the RO- group on day 28. All patients except 1 received complete protocol treatment, and 15 of them did not have disease progression. The 2-year reactivation/progression-free survival (RFS) for RO+ was 76.9% with a median follow-up of 21 months and 83.3% with a median follow-up of 29 months for RO-. Overall survival is 100%. Importantly, 1 patient experienced secondary myelodysplastic syndrome after 14 months from vemurafenib cessation. Our study demonstrates that combined vemurafenib plus 2-CdA and Ara-C is effective in a cohort of children with LCH, and the toxicity is manageable. This trial is registered at www.clinicaltrials.gov as NCT03585686.

Letterer-Siwe disease presenting with gastrointestinal and cutaneous manifestations.

Histiocytosis is a set of distinct proliferative illnesses defined by the proliferation and infiltration of varied numbers of dendritic cells, macrophages, and monocytes in the afflicted tissues. The skin and other organs may be impacted by the inflammatory infiltration. It can occur at any age. The severity of the symptoms can range from mild to severe, depending on the degree and type of organ involvement. Although certain forms of histiocytosis can be fatal, others can be treated successfully without sequelae. Langerhans cell histiocytosis manifests itself clinically in both children and adults. A combination of clinical, histological, and radiological tests is required to achieve a diagnosis. A severe, multisystemic, acute form of Langerhans cell histiocytosis is called Letterer-Siewe illness, which usually affects infants in their first year of life. In this article, we provide a brief literature review and a case study of a 9-month-old girl who presented with recurring gastrointestinal problems as the first sign of Letterer-Siwe disease.