RESUMEN
BACKGROUND: Novel treatments are needed to control refractory status epilepticus (SE). This study aimed to assess the potential effectiveness of fenfluramine (FFA) as an acute treatment option for SE. We present a summary of clinical cases where oral FFA was used in SE. METHODS: A case of an adult patient with Lennox-Gastaut syndrome (LGS) who was treated with FFA due to refractory SE is presented in detail. To identify studies that evaluated the use of FFA in SE, we performed a systematic literature search. RESULTS: Four case reports on the acute treatment with FFA of SE in children and adults with Dravet syndrome (DS) and LGS were available. We report in detail a 30-year-old woman with LGS of structural etiology, who presented with generalized tonic and dialeptic seizures manifesting at high frequencies without a return to clinical baseline constituting the diagnosis of SE. Treatment with anti-seizure medications up to lacosamide 600 mg/d, brivaracetam 300 mg/d, valproate 1,600 mg/d, and various benzodiazepines did not resolve the SE. Due to ongoing refractory SE and following an unremarkable echocardiography, treatment was initiated with FFA, with an initial dose of 10 mg/d (0.22 mg/kg body weight [bw]) and fast up-titration to 26 mg/d (0.58 mg/kg bw) within 10 days. Subsequently, the patient experienced a resolution of SE within 4 days, accompanied by a notable improvement in clinical presentation and regaining her mobility, walking with the assistance of physiotherapists. In the three cases reported in the literature, DS patients with SE were treated with FFA, and a cessation of SE was observed within a few days. No treatment-emergent adverse events were observed during FFA treatment in any of the four cases. CONCLUSIONS: Based on the reported cases, FFA might be a promising option for the acute treatment of SE in patients with DS and LGS. Observational data show a decreased SE frequency while on FFA, suggesting a potentially preventive role of FFA in these populations. KEY POINTS: We summarize four cases of refractory status epilepticus (SE) successfully treated with fenfluramine. Refractory SE resolved after 4-7 days on fenfluramine. Swift fenfluramine up-titration was well-tolerated during SE treatment. Treatment-emergent adverse events on fenfluramine were not observed. Fenfluramine might be a valuable acute treatment option for SE in Dravet and Lennox-Gastaut syndromes.
RESUMEN
Internal tandem duplications (ITD) in the receptor tyrosine kinase FLT3 occur in 25 % of acute myeloid leukemia (AML) patients, drive leukemia progression and confer a poor prognosis. Primary resistance to FLT3 kinase inhibitors (FLT3i) quizartinib, crenolanib and gilteritinib is a frequent clinical challenge and occurs in the absence of identifiable genetic causes. This suggests that adaptive cellular mechanisms mediate primary resistance to on-target FLT3i therapy. Here, we systematically investigated acute cellular responses to on-target therapy with multiple FLT3i in FLT3-ITD + AML using recently developed functional translatome proteomics (measuring changes in the nascent proteome) with phosphoproteomics. This pinpointed AKT-mTORC1-ULK1-dependent autophagy as a dominant resistance mechanism to on-target FLT3i therapy. FLT3i induced autophagy in a concentration- and time-dependent manner specifically in FLT3-ITD + cells in vitro and in primary human AML cells ex vivo. Pharmacological or genetic inhibition of autophagy increased the sensitivity to FLT3-targeted therapy in cell lines, patient-derived xenografts and primary AML cells ex vivo. In mice xenografted with FLT3-ITD + AML cells, co-treatment with oral FLT3 and autophagy inhibitors synergistically impaired leukemia progression and extended overall survival. Our findings identify a molecular mechanism responsible for primary FLT3i treatment resistance and demonstrate the pre-clinical efficacy of a rational combination treatment strategy targeting both FLT3 and autophagy induction.
