Bio‐Responsive Macromolecular Drug and Small‐Molecular Drug Conjugates: Nanoparticulate Prodrugs for Tumor Microenvironment Heterogeneity Management and Therapeutic Response Enhancement

Abstract How to break through the poor response of current drug therapy, which often resulted from tumor microenvironment heterogeneity (TMH), remains an enormous challenge in the treatment of critical diseases. In this work, a practical solution on bio‐responsive dual‐drug conjugates for overcoming TMH and improving antitumor treatment, which integrates the advantages of macromolecular drugs and small‐molecular drugs, is proposed. Nanoparticulate prodrugs based on small‐molecular drug and macromolecular drug conjugates are designed as a robust weapon for programmable multidrug delivery at tumor‐specific sites: the tumor microenvironment acid condition triggers delivery of macromolecular aptamer drugs (AX102) to manage TMH (including tumor stroma matrix, interstitial fluid pressure, vasculature network, blood perfusion, and oxygen distribution), and intracellular lysosomal acid condition activates rapid release of small‐molecular drugs (doxorubicin and dactolisib) to enhance curative effects. As compared with doxorubicin chemotherapy, the tumor growth inhibition rate is enhanced by 47.94% after multiple tumor heterogeneity management. This work verifies that the nanoparticulate prodrugs facilitate TMH management and therapeutic response enhancements, as well as elucidates synergetic mechanisms for drug resistance reversal and metastasis inhibition. It is hoped that the nanoparticulate prodrugs will be an excellent demonstration of the co‐delivery of small‐molecular drugs and macromolecular drugs.