Provided are drug delivery compositions and devices useful for the treatment and/or prevention of cancer and metastatic tumors. For example, a drug delivery composition and/or device is provided that comprises a biodegradable scaffold or biomaterial comprising one or more agents that inhibit one or more proinflammatory pathways, such as one or more immune responses mediated by a p38 mitogen-activated protein kinase (MAPK) pathway. In some embodiments, a drug delivery composition and/or device may further comprise one or more agents that activate the innate immune system (e.g., STING agonists) and/or the adaptive immune system (e.g., anti-PD- 1 antibodies). In some embodiments, a drug delivery composition and/or device may include a cytokine (e.g., IL- 15 superagonist). In some embodiments, a drug delivery composition and/or device can be administered to a tumor resection site (e.g., a void volume resulting from a tumor resection). Such intraoperative administration can prevent tumor regrowth and/or tumor metastasis. Also provided are methods of making drug delivery compositions and devices as well as kits containing materials to provide the same.
