Abstract Cerulean Pharma Inc.'s Dynamic Tumor Targeting™ Platform creates nanoparticle-drug conjugates (NDCs) designed to significantly mitigate a payload's limitations by providing sustained drug delivery to the tumor and superior therapeutic index through controlled release kinetics. By conjugating drug payloads to our novel β-cyclodextrin-PEG copolymer through linker strategies that allow modulation of release and pharmacokinetics (PK), we provide advantages over entrapped nanoparticle strategies, e.g., polymeric nanoparticles and liposomes. Cerulean has two NDCs in the clinic, CRLX101 and CRLX301, evidencing the translatability of our technology. CRLX101 has been dosed in over 350 patients and CRLX301 is in an ongoing Phase 1/2a trial. Our Dynamic Tumor Targeting Platform is applicable to a diverse range of drug payload possibilities, including small molecules with a host of physiochemical properties, i.e., hydrophobic and hydrophilic payloads, and functional groups with chemical handles for conjugation. To illustrate the capabilities of our platform we will present the biological impact of a series of cabazitaxel-containing NDCs with linkers encompassing a diversity of in vitro release rates. In vivo PK studies showed high and sustained levels of released drug in tumor tissues (>168 hrs), and in vivo mouse tumor model studies demonstrated vastly improved efficacy, i.e., tumor regression and significant tumor growth delay, and survival over separately dosed cabazitaxel including efficacy in a taxane-resistant tumor model. Cerulean continues to expand its platform through the development of new and emerging capabilities to treat patients living with cancer. In this regard, we also will address the future evolution of NDCs, including the conjugation of multiple payloads to a single NDC and the development of antibody-conjugated NDCs. This abstract is also being presented as Poster B43. Citation Format: Chester Metcalf, III, Derek van der Poll, Liang Zhao, Tiffany Halo, Doug Lazarus, Adam Stockmann, Christian Peters, Donna Brown, Roy Case, Ellen Rohde, Lata Jayaraman, Hongwei Wang, Tiffany Crowell, Adrian Senderowicz, Scott Eliasof. Significant improvements in therapeutic index for conjugated payloads using a nanoparticle-drug conjugate (NDC) platform to provide sustained drug release and potentially improved anticancer effects. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr PR10.