Next-Generation Nano-Drug Delivery Systems for Cancer Immunotherapy: Bridging Innovation and Clinical Translation

Background: Cancer immunotherapy, including checkpoint inhibitors and CAR-T cell therapies, has transformed oncology. However, systemic toxicity, poor tumor penetration, immunosuppressive tumor microenvironment, and limited response rates of 20–40% in solid tumors continue to restrict therapeutic success. Nanotechnology-based drug delivery systems offer a promising avenue to overcome these limitations through targeted delivery, controlled release, and co-loading of multiple therapeutic agents. Objectives: This review aims to comprehensively examine recent advances in nano-drug delivery platforms for cancer immunotherapy, evaluate their mechanisms of tumor targeting and immune modulation, assess progress in clinical translation, and identify key challenges and future directions in the field. Methods: A systematic review of published literature was conducted covering lipid nanoparticles, biomimetic nanoparticles, stimuli-responsive carriers, polymeric and inorganic nanoplatforms, and their applications in checkpoint inhibitor delivery, cancer vaccines, tumor microenvironment modulation, and immunogenic cell death induction. Clinical trial data, FDA-approved nanomedicines, and regulatory frameworks were also analyzed. Key findings: Lipid nanoparticles, particularly ionizable LNP-mRNA systems validated by COVID-19 vaccines, have demonstrated strong clinical potential for personalized neoantigen vaccines and cytokine delivery, with Moderna's mRNA-4157 showing promising Phase II results in melanoma. Biomimetic nanoparticles utilizing cancer cell, macrophage, and platelet membranes exploit homotypic targeting and immune evasion but face significant standardization and manufacturing challenges. Stimuli-responsive systems exploiting tumor pH, matrix metalloproteinases, redox gradients, and external triggers such as near-infrared light and magnetic fields enable selective intratumoral drug release with reduced systemic toxicity. Several nanomedicines including Doxil, Abraxane, Onivyde, and Vyxeos have achieved FDA approval, validating the clinical feasibility of the nanomedicine approach. Active and passive targeting strategies, when combined, demonstrate superior efficacy over either mechanism alone. Artificial intelligence and multi-omics integration are emerging as powerful tools for nanoparticle design optimization and patient stratification. Challenges: Critical barriers to clinical translation include heterogeneity of the enhanced permeability and retention effect across patients and tumor types, manufacturing scalability and batch-to-batch reproducibility, high production costs particularly for personalized nanovaccines, anti-PEG antibody development, complement activation-related pseudoallergy, and evolving regulatory pathways for biomimetic and hybrid nanoplatforms. Conclusions: Nanotechnology holds significant potential to enhance cancer immunotherapy outcomes, particularly for difficult-to-treat solid tumors. Realizing this potential requires interdisciplinary collaboration, rigorous clinical validation, standardized manufacturing processes, and biomarker-driven patient selection. The convergence of nanomedicine, immunotherapy, and personalized medicine may ultimately enable curative outcomes in metastatic cancers.