BACKGROUND: Atherosclerosis commences with endothelial dysfunction and the retention of cholesterol within the vessel wall, followed by a chronic inflammatory response. Lowering LDL-C (low-density lipoprotein-cholesterol; such as statins and PCSK9 [proprotein convertase subtilisin/kexin type 9] inhibitors) is the mainstay of current treatment for patients with atherosclerotic cardiovascular diseases, but residual inflammatory risk remains high. METHODS: To address this pressing challenge, we used connectivity map screening of Food and Drug Administration–approved drugs, using perturbational data sets obtained from TNF-α (tumor necrosis factor-α) and IL (interleukin)-1β–stimulated human endothelial cells. Male and female Ldlr −/− mouse models were used to evaluate the in vivo antiatherosclerotic effect of the hit compound identified. RESULTS: This screening endeavor allows us to identify neratinib, a clinical drug against breast cancer, as the hit compound with broad anti-inflammatory actions in endothelial cells. Further studies reveal that neratinib inhibited endothelial cell inflammation elicited by 3 different proinflammatory stimuli (TNF-α, IL-1β, and lipopolysaccharide). Intriguingly, the anti-inflammatory effect of neratinib was independent of its classical target HER2 (human epidermal growth factor receptor 2)/ERBB2 inhibition. Further mechanistic investigation revealed that neratinib directly binds to ASK1 (apoptosis signal-regulating kinase 1) and suppresses ASK1 activation. Importantly, in both male and female Ldlr −/− mice, treatment with neratinib decreased the plaque burden, reduced the necrotic core size, and mitigated lesional macrophage infiltration. Of translational impact, we observed that neratinib, in conjunction with the use of rosuvastatin (a standard lipid-lowering drug), produced superior antiatherosclerotic effects compared with statin monotherapy. Olink proteomics study pinpointed that combination treatment alleviated inflammation-related cytokines/chemokines in the serum from Ldlr −/− mice. CONCLUSIONS: Taken together, these findings support the concept that neratinib could be tested as a repurposed drug for vascular inflammation and atherosclerosis, thereby streamlining efforts to translate preclinical discoveries to clinical testing in humans.