Vemurafenib for Refractory Multisystem Langerhans Cell Histiocytosis in Children: An International Observational Study.

PURPOSE: Off-label use of vemurafenib (VMF) to treat BRAFV600E mutation-positive, refractory, childhood Langerhans cell histiocytosis (LCH) was evaluated. PATIENTS AND METHODS: Fifty-four patients from 12 countries took VMF 20 mg/kg/d. They were classified according to risk organ involvement: liver, spleen, and/or blood cytopenia. The main evaluation criteria were adverse events (Common Terminology Criteria for Adverse Events [version 4.3]) and therapeutic responses according to Disease Activity Score. RESULTS: LCH extent was distributed as follows: 44 with positive and 10 with negative risk organ involvement. Median age at diagnosis was 0.9 years (range, 0.1 to 6.5 years). Median age at VMF initiation was 1.8 years (range, 0.18 to 14 years), with a median follow-up of 22 months (range, 4.3 to 57 months), whereas median treatment duration was 13.9 months (for 855 patient-months). At 8 weeks, 38 complete responses and 16 partial responses had been achieved, with the median Disease Activity Score decreasing from 7 at diagnosis to 0 (P < .001). Skin rash, the most frequent adverse event, affected 74% of patients. No secondary skin cancer was observed. Therapeutic plasma VMF concentrations (range, 10 to 20 mg/L) seemed to be safe and effective. VMF discontinuation for 30 patients led to 24 LCH reactivations. The blood BRAFV600E allele load, assessed as circulating cell-free DNA, decreased after starting VMF but remained positive (median, 3.6% at diagnosis, and 1.6% during VMF treatment; P < .001) and was associated with a higher risk of reactivation at VMF discontinuation. None of the various empirical therapies (hematopoietic stem-cell transplantation, cladribine and cytarabine, anti-MEK agent, vinblastine, etc) used for maintenance could eradicate the BRAFV600E clone. CONCLUSION: VMF seemed safe and effective in children with refractory BRAFV600E-positive LCH. Additional studies are needed to find effective maintenance therapy approaches.

Cladribine and cytarabine in refractory multisystem Langerhans cell histiocytosis: results of an international phase 2 study.

An international phase 2 study combining cladribine and cytarabine (Ara-C) was initiated for patients with refractory, risk-organ-positive Langerhans cell histiocytosis (LCH) in 2005. The protocol, comprising at least two 5-day courses of Ara-C (1 g/m(2) per day) plus cladribine (9 mg/m(2) per day) followed by maintenance therapy, was administered to 27 patients (median age at diagnosis, 0.7 years; median follow-up, 5.3 years). At inclusion, all patients were refractory after at least 1 course of vinblastine (VBL) plus corticosteroid, all had liver and spleen involvement, and 25 patients had hematologic cytopenia. After 2 courses, disease status was nonactive (n = 2), better (n = 23), or stable (n = 2), with an overall response rate of 92%. Median disease activity scores decreased from 12 at the start of therapy to 3 after 2 courses (P < .0001). During maintenance therapy, 4 patients experienced reactivation in risk organs. There were 4 deaths; 2 were related to therapy toxicity and 2 were related to reactivation. All patients experienced severe toxicity, with World Health Organization grade 4 hematologic toxicity and 6 documented severe infections. The overall 5-year survival rate was 85% (95% confidence interval, 65.2%-94.2%). Thus, the combination of cladribine/Ara-C is effective therapy for refractory multisystem LCH but is associated with high toxicity.

Skeletal involvement in Langerhans cell histiocytosis.

UNLABELLED: Langerhans cell histiocytosis (LCH) represents a disorder characterised by an abnormal accumulation of histiocytes in miscellaneous tissues. The bone is commonly affected, especially the flat bones, the spine and the long bones. Some lesions in children such as a "vertebra plana" or a solitary lytic lesion of the skull may be suggestive for LCH, whereas others can be confused with a malignant tumour or osteomyelitis. This pictorial essay presents the main usual and unusual skeletal manifestations observed in LCH. TEACHING POINTS: • Osseous involvement in children with LCH is very similar to that seen in multiple myeloma. • A solitary lytic lesion of the cranial vault is a typical radiographic finding of LCH. • A vertebra plana appearance in the spine is another typical radiographic finding. • Extensive signal intensity changes within bone marrow on MRI are a helpful sign for the diagnosis. • In long bones, endosteal scalloping may be responsible for a "budding appearance".

Excellent survival following two courses of COPAD chemotherapy in children and adolescents with resected localized B-cell non-Hodgkin's lymphoma: results of the FAB/LMB 96 international study.

High cure rates are possible in children with localized mature B-cell lymphoma (B NHL) using a variety of chemotherapeutic strategies. To reduce late sequelae, the duration and intensity of chemotherapy has been progressively reduced. The Lymphome Malins de Burkitt (LMB) 89 study reported long-term survival in almost all children with localized resected disease treated with two courses of COPAD (cyclophosphamide, vincristine, prednisolone and doxorubicin). This study was designed to confirm the effectiveness of this approach in a larger number of patients in a multinational co-operative study. The patient cohort was part of an international study (French-American-British LMB 96), which included all disease stages and involved three national groups. Patients in this part of the study had resected stage I or completely resected abdominal stage II disease. Following surgery, two courses of COPAD were given, without intrathecal (IT) chemotherapy. One hundred and thirty-two children were evaluable. Two of 264 (0.9%) courses were associated with grade IV toxicity (one stomatitis and one infection). With a median follow up of 50.5 months, the 4 year event-free survival is 98.3% and overall survival is 99.2%. Children with resected localized B-NHL can be cured with minimal toxicity following two courses of low intensity treatment without IT chemotherapy.