Targeting Pro-Inflammatory Interleukin-1 Beta Signaling to Modulate Neuroinflammatory Processes Associated with Cognitive Decline in Dementia with Lewy Bodies.

Interleukin-1 beta (IL-1β) is implicated as a molecular driver of cognitive decline in Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), potentially through activation of pro-inflammatory pathways within the neuron that impair synaptic function. Because pro-inflammatory IL-1β signaling depends on p38α kinase, the oral brain-penetrant p38α inhibitor neflamapimod has the potential to reverse synaptic dysfunction and treat cognitive decline in these contexts. Neflamapimod has also shown positive effects in animal models and in clinical studies in AD and DLB. Herein we evaluated neflamapimod effects on pro-inflammatory IL-1β signaling in vitro and in patients with AD or DLB. In human PBMCs, neflamapimod inhibited IL-1β-induced IL-6 and IL-8 production with EC50 values of 6.3 ± 1.3 nM and 7.1 ± 3.2 nM, respectively. In AD, six weeks of neflamapimod 40 mg BID treatment reduced CSF levels of IL-6 and IL-8, with maximal effects at trough drug concentration ≥4 ng/mL (9 nM). In DLB, neflamapimod 40 mg TID increased the plasma Aβ42/40 ratio and reduced plasma GFAP levels, treatment effects consistent with reduced pro-inflammatory IL-1β signaling. Collectively, these results support the hypothesis that inhibition of p38α-dependent IL-1β signaling may beneficially modulate neuroinflammatory processes that otherwise are associated with cognitive decline in DLB, and potentially in AD.