Larotrectinib, a selective TRK tyrosine kinase inhibitor (TKI), has demonstrated histology-agnostic efficacy in patients with TRK fusion-positive cancers. While responses to TRK inhibition can be dramatic and durable, duration of response may eventually be limited by acquired resistance. LOXO-195 is a novel, selective TRK TKI designed to overcome acquired resistance mediated by recurrent kinase domain (solvent front and xDFG) mutations identified in multiple patients who have developed resistance to TRK TKIs. Activity against these acquired mutations was confirmed in enzyme and cell-based assays and in vivo tumor models. As clinical proof of concept, the first two patients with TRK fusion-positive cancers that developed acquired resistance mutations on larotrectinib were treated with LOXO-195 on a first-in-human basis, utilizing rapid dose titration guided by pharmacokinetic assessments. This approach led to rapid tumor responses and extended the overall duration of disease control achieved with TRK inhibition in both patients.

Congenital LCMV infection can have diverse presenting signs, neuroimaging abnormalities, and clinical outcomes. In the companion article to this study, we utilize an animal model to show that the clinical and pathological diversity in congenital LCMV infection is likely due to differences in the gestational timing of infection.

Familial cold autoinflammatory syndrome (FCAS) and the related autoinflammatory disorders, Muckle-Wells syndrome and neonatal onset multisystem inflammatory disease, are characterized by mutations in the CIAS1 gene that encodes cryopyrin, an adaptor protein involved in activation of IL-converting enzyme/caspase-1. Mutations in cryopyrin are hypothesized to result in abnormal secretion of caspase-1-dependent proinflammatory cytokines, IL-1β and IL-18. In this study, we examined cytokine secretion in PBMCs from FCAS patients and found a marked hyperresponsiveness of both IL-1β and IL-18 secretion to LPS stimulation, but no evidence of increased basal secretion of these cytokines, or alterations in basal or stimulated pro-IL-1β levels. VX-765, an orally active IL-converting enzyme/caspase-1 inhibitor, blocked IL-1β secretion with equal potency in LPS-stimulated cells from FCAS and control subjects. These results further link mutations in cryopyrin with abnormal caspase-1 activation, and support the clinical testing of caspase-1 inhibitors such as VX-765 in autoinflammatory disorders.

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To characterize the antibody response to the Epstein-Barr virus (EBV) in MS, we studied serum anti-EBV nuclear antigen (anti-EBNA) and anti-EBV capsid antigen (anti-EBVCA) titers. Both titers were assayed in 93 age- and sex-matched pairs of MS patients and controls. Anti-EBVCA titers were measured by indirect immunofluorescence and anti-EBNA titers by anticomplement immunofluorescence. The seropositivity rate of both anti-EBVCA and anti-EBNA in MS patients was 100%, compared with 84% in controls (p less than 0.0001). Both anti-EBVCA and anti-EBNA titers were significantly higher in MS patients than in controls (p less than 0.0001). The data suggest that EBV has a significant seroepidemiologic association with MS, but they do not define what role EBV antibodies play in the pathogenesis of the disease.