Dramatic efficacy of vemurafenib in both multisystemic and refractory Erdheim-Chester disease and Langerhans cell histiocytosis harboring the BRAF V600E mutation.

Histiocytoses are rare disorders of unknown origin with highly heterogeneous prognosis. BRAFV600E gain-of-function mutations have been observed in 57% of cases of Langerhans cell histiocytosis (LCH) and 54% of cases of Erdheim-Chester disease (ECD), but not in other types of histiocytoses. Targeted therapy with an inhibitor of mutated BRAF (vemurafenib) improves survival of patients with melanoma. Here, we report vemurafenib treatment of 3 patients with multisystemic and refractory ECD carrying the BRAFV600E mutation; 2 also had skin or lymph node LCH involvement. The patients were assessed clinically, biologically (CRP values), histologically (skin biopsy), and morphologically (positron emission tomography [PET], computed tomography and magnetic resonance imaging). For all patients, vemurafenib treatment led to substantial and rapid clinical and biologic improvement, and the tumor response was confirmed by PET, computed tomography, and/or magnetic resonance imaging 1 month after treatment initiation. For the first patient treated, the PET response increased between months 1 and 4 of treatment. The treatment remained effective after 4 months of follow-up although persistent disease activity was still observed. Treatment with vemurafenib, a newly approved BRAF inhibitor, should be considered for patients with severe and refractory BRAFV600E histiocytoses, particularly when the disease is life-threatening.

Reproducible and sustained efficacy of targeted therapy with vemurafenib in patients with BRAF(V600E)-mutated Erdheim-Chester disease.

PURPOSE: Histiocytoses are rare disorders with heterogeneous prognosis. BRAF(V600E) mutations have been observed in half of patients with Langerhans cell histiocytosis (LCH) and in 50% to 100% of patients with Erdheim-Chester disease (ECD) patients. We recently reported short-term efficacy of a BRAF inhibitor (vemurafenib) in three patients with multisystemic ECD. PATIENTS AND METHODS: Vemurafenib was given to eight patients with multisystemic ECD with CNS and/or cardiac involvement. All patients were refractory to first-line treatment and harbored a BRAF(V600E) mutation. Four patients also had LCH lesions. Positron emission tomography (PET) scan response at month 6 was used as the main evaluation criterion. Secondary evaluation criteria were comparison at baseline and at last visit of PET and of cardiovascular and cerebral infiltrations (computed tomography scan and magnetic resonance imaging [MRI]). RESULTS: All patients were partial metabolic responders at 6 months of vemurafenib, and the median reduction in maximum standardized uptake value was 63.5% (range, 41.3% to 86.9%). Evaluation of cardiac and aortic infiltrations showed that seven patients had a partial response and one patient had stable disease according to surface measurements derived from RECIST criteria. The four patients with infratentorial CNS infiltration had an objective decrease of the lesions on MRI. All patients had an improvement of general symptoms and a persistent response to vemurafenib, with a median follow-up time of 10.5 months (range, 6 to 16 months). Skin adverse effects were frequent and severe. CONCLUSION: Vemurafenib has an objective and sustained efficacy in BRAF(V600E)-mutated ECD as second-line therapy. In contrast to melanoma, no resistance has emerged to date after 6 to 16 months.

Anti-HMGCR autoantibodies in European patients with autoimmune necrotizing myopathies: inconstant exposure to statin.

Necrotizing autoimmune myopathy (NAM) is a group of acquired myopathies characterized by prominent myofiber necrosis with little or no muscle inflammation. Recently, researchers identified autoantibodies (aAb) against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with NAM, especially in statin-exposed patients. Here we report what is to our knowledge the first European cohort of patients with NAM.The serum of 206 patients with suspicion of NAM was tested for detection of anti-HMGCR aAb using an addressable laser bead immunoassay. Forty-five patients were found to be anti-HMGCR positive. Their mean age was 48.9 ± 21.9 years and the group was predominantly female (73.3%). Statin exposure was recorded in 44.4% of patients. Almost all patients had a muscular deficit (97.7%), frequently severe (Medical Research Council [MRC] 5 ≤3 in 75.5%). Subacute onset (<6 mo) was noted for most of them (64.4%). Nevertheless, 3 patients (6.6%) had a slowly progressive course over more than 10 years. Except for weight loss (20%), no extramuscular sign was observed. The mean CK level was high (6941 ± 8802 IU/L) and correlated with muscle strength evaluated by manual muscle testing (r = -0.37, p = 0.03). Similarly, anti-HMGCR aAb titers were correlated with muscular strength (r = -0.31; p = 0.03) and CK level (r = 0.45; p = 0.01). Mean duration of treatment was 34.1 ± 40.8 months, and by the end of the study no patient had been able to stop treatment.This study confirms the observation and description of anti-HMGCR aAb associated with NAM. The majority of patients were statin naive and needed prolonged treatments. Some patients had a dystrophic-like presentation. Anti-HMGR aAb titers correlated with CK levels and muscle strength, suggesting their pathogenic role.

Should we systematically perform central nervous system imaging in patients with Whipple's endocarditis?

BACKGROUND: Whipple's endocarditis is an uncommon disease, with approximately 100 cases reported to date. Case series suggest that Whipple's endocarditis usually presents without extracardiac manifestations of Whipple's disease. METHODS: We report 4 consecutive cases of Whipple's endocarditis associated with brain lesions. All patients fulfilled Duke Criteria for definite endocarditis. Whipple's disease was diagnosed through 16S rRNA polymerase chain reaction assays on valves excised from patients with culture-negative endocarditis (n=3) or through polymerase chain reaction and periodic acid staining-positive foamy macrophages on duodenal biopsy (n=1). RESULTS: All patients were male, aged 56 to 72 years. They presented with mitral (n=1), aortic (n=1), mitral and aortic (n=1), and tricuspid (n=1) endocarditis. Brain magnetic resonance imaging was performed because of mild-to-moderate cognitive disorders (n=3) or ataxia (n=1) and revealed multiple (n=3) or solitary (n=1) contrast-enhancing lesions. Cerebrospinal fluid studies revealed meningitis in 1 case. Polymerase chain reaction assays on cerebrospinal fluid were negative for all patients. All patients received intravenous ceftriaxone (2-4 weeks) associated with gentamicin (2 weeks), followed by 1 year of oral trimethoprim-sulfamethoxazole, with favorable outcomes. CONCLUSION: Whipple's associated central nervous system disease may be common but frequently undiagnosed, in patients with Whipple's endocarditis. Because treatment is different when neurologic disease is present (ie, trimethoprim-sulfamethoxazole vs doxycycline/hydroxychloroquine), clinicians should consider brain imaging in patients diagnosed with Whipple's endocarditis.