Blockade of immune checkpoints in lymph nodes through locoregional delivery augments cancer immunotherapy
Menée sur des modèles murins de cancer, cette étude met en évidence l'intérêt d'administrer près de la tumeur les inhibiteurs de points de contrôle immunitaire pour améliorer l'efficacité du traitement
Immune checkpoint inhibitors have shown great promise against multiple types of cancer, but they are still not sufficiently effective to help many patients. Moreover, systemic administration of immune checkpoint blockade can cause severe immune side effects, which limit its use. To identify safer and more effective ways to administer immune checkpoint blockade, Francis et al. systematically compared different routes of administration, evaluating the accumulation of immune checkpoint antibodies in tumor-draining lymph nodes and in the tumors themselves. Locoregional treatment was both more effective and safer than systemic therapy in multiple mouse models of cancer, and intradermal delivery near the tumor was sufficient, without requiring direct intratumoral injection.Systemic administration of immune checkpoint blockade (ICB) monoclonal antibodies (mAbs) can unleash antitumor functions of T cells but is associated with variable response rates and off-target toxicities. We hypothesized that antitumor efficacy of ICB is limited by the minimal accumulation of mAb within tissues where antitumor immunity is elicited and regulated, which include the tumor microenvironment (TME) and secondary lymphoid tissues. In contrast to systemic administration, intratumoral and intradermal routes of administration resulted in higher mAb accumulation within both the TME and its draining lymph nodes (LNs) or LNs alone, respectively. The use of either locoregional administration route resulted in pronounced T cell responses from the ICB therapy, which developed in the secondary lymphoid tissues and TME of treated mice. Targeted delivery of mAb to tumor-draining lymph nodes (TdLNs) alone was associated with enhanced antitumor immunity and improved therapeutic effects compared to conventional systemic ICB therapy, and these effects were sustained at reduced mAb doses and comparable to those achieved by intratumoral administration. These data suggest that locoregional routes of administration of ICB mAb can augment ICB therapy by improving immunomodulation within TdLNs.