Cyclodextrin-Based Delivery of the Annexin A1 Mimetic Peptide Ac2-26 Enhances Anti-Inflammatory Effects and Prevents Dengue-Induced Lethality in Combination with Antiviral Therapy

ABSTRACT Severe dengue is characterized by systemic inflammation, cytokine storm, vascular leakage, and hemorrhagic manifestations, largely driven by the host immune response to dengue virus (DENV) infection. Despite its burden, no licensed antivirals or host-directed therapies are currently available. Our group has previously identified Annexin A1 (AnxA1) as an endogenous regulator of inflammation in dengue. Treatment with the AnxA1 peptidomimetic, Ac 2-26 , improved clinical outcomes in murine models of severe dengue by promoting resolution of inflammation without affecting viral control. To explore new delivery strategies, we developed a novel formulation of Ac 2-26 complexed with hydroxypropyl-β-cyclodextrin (CDX-Ac 2-26 ). In DENV-2-infected A129 mice, both intraperitoneal and oral CDX-Ac 2-26 improved clinical scores and reversed thrombocytopenia. Notably, CDX-Ac 2-26 reduced mast cell degranulation, MCPT-1 plasma levels, and CCL2 expression in spleen, with no effect on viral titers, indicating a host-targeted mechanism and overcoming the anti-inflammatory effects of the free peptide. Intraperitoneal administration achieved the same efficacy as oral dosing with only one-third of the dose. Importantly, the combination of CDX-Ac 2-26 with the antiviral nucleotide analog sofosbuvir fully prevented disease and mortality in infected mice, highlighting a combinatorial effect between host-directed and antiviral therapies. These findings underscore the therapeutic potential of anti-inflammatory/pro-resolving strategies in severe dengue and support the development of CDX-Ac 2-26 as a novel adjunctive treatment. Combining anti-inflammatory and antiviral approaches may enhance efficacy and reduce treatment-associated toxicity, offering a promising path for clinical translation. What is already known on this topic? Plasma levels of Annexin A1 are inversely correlated with the severity of clinical outcomes in dengue virus infection. The Annexin A1 peptidomimetic Ac 2-26 exhibits anti-inflammatory and pro-resolving effects against severe dengue in a murine model. What does this study add? The Ac 2-26 -cyclodextrin complex enhances the anti-inflammatory effects of the peptide against dengue virus infection, allowing for lower dosing and oral administration. The administration of the CDX-Ac 2-26 with a nucleoside analog antiviral exhibits a combinatorial effectt, providing complete protection against the lethal outcome of severe dengue. What is the clinical significance? Current dengue treatment relies on symptomatic management, as no directed anti-inflammatory agents or antivirals are currently available. We have identified a novel host-targeted strategy to resolve the disease. Our findings strongly support CDX-Ac 2-26 as a promising adjunctive treatment strategy in combination with antiviral therapy for severe dengue, highlighting the potential of combinatorial approaches.