Addressing Clinical Challenges of Platinum Anticancer Drugs through Rational Chemical Design

Platinum (Pt)-based anticancer drugs have been a cornerstone of chemotherapy for decades, yet their clinical application remains constrained by dose-limiting systemic toxicity and drug resistance. In this Account, we summarize our systematic efforts to address these challenges through two complementary strategies: 1) functionalization of Pt(IV) prodrugs and 2) spatially controlled targeted delivery. The kinetic inertness and octahedral geometry of Pt(IV) complexes offer a versatile platform for axial functionalization, allowing the integration of diverse bioactive ligands that are released upon intracellular reduction. Exploiting this feature, we have developed multifunctional Pt(IV) prodrugs that co-target DNA damage repair and apoptotic pathways, rewire cholesterol and energy metabolism, induce nonapoptotic cell death including PANoptosis and autophagy-associated death, and epigenetically silence resistance-associated gene networks via chromatin compaction. To engage the tumor immune microenvironment, we have incorporated immunomodulators─including STING agonists, TREM2/CD33 inhibitors, and STAT3 blockers─to amplify innate and adaptive antitumor immunity. Furthermore, we have developed radiotherapy-responsive Pt(IV) prodrugs that undergo rapid, X-ray-triggered reduction mediated by hydrated electrons, enabling spatiotemporally precise drug activation with markedly attenuated systemic toxicity. This strategy is currently advancing toward clinical translation through IND-enabling studies. In parallel, we have established targeted delivery platforms to improve the spatial precision of Pt agents. Mitochondria-targeted complexes redirect cytotoxicity to an organelle lacking efficient DNA repair, disrupting bioenergetics and triggering intrinsic apoptosis. At the tissue level, biotin-mediated targeting exploits overexpressed vitamin transporters for tumor-selective accumulation, while Pt(IV)-antibody conjugates (Pt-ADCs) achieve antigen-specific delivery, upregulate tumor MHC-I expression, expand TCR clonotypes, and synergize with PD-1 blockade. Additionally, a stimuli-responsive in situ self-assembly strategy enables enzyme-triggered nanostructure formation and intracellular disassembly for enhanced tumor accumulation and burst drug release. An immunocompetent patient-derived organoid platform has been established to screen these agents in a clinically relevant setting. The integration of multifunctional modulation, targeted delivery, and externally controlled activation within single Pt-based systems creates a synergistic framework that simultaneously addresses resistance and toxicity. Moving forward, our research will focus on optimizing pharmaceutical properties, advancing radiotherapy-responsive Pt(IV) prodrugs and Pt-ADCs toward clinical evaluation, and refining predictive screening platforms. These programmable Pt therapeutics hold considerable promise for delivering safer and more effective precision chemotherapy to cancer patients.