Intratumoral immunotherapy using platelet-cloaked nanoparticles enhances antitumor immunity in solid tumors

Summary

This preclinical study tests localized delivery of the Toll-like receptor agonist resiquimod as a way to activate immunity inside solid tumors while avoiding adverse effects associated with systemic exposure. Resiquimod was loaded into nanoparticles cloaked with platelet membrane, whose natural interactions with the tumor microenvironment were intended to increase local engagement. After intratumoral administration, the formulation strongly activated local immunity and caused complete regression in a colorectal tumor model. Animals were also protected against repeated tumor challenge, indicating that the response included immune memory rather than only acute local toxicity. In a more aggressive breast-cancer model, the same treatment delayed primary-tumor growth and inhibited lung metastasis. The principal finding is that platelet camouflage can support concentrated intratumoral action of an immunostimulatory payload across two tumor settings, producing local control and, in the colorectal model, durable protective immunity. Its significance is a biomimetic strategy for increasing the usefulness of potent innate-immune agonists through route and carrier design. The abstract does not quantify systemic cytokine exposure or adverse events, establish which platelet interactions drive the effect, or show whether the results extend to intravenous dosing or human tumors.