Abstract 3705: Targeted anticancer drug delivery to Ewing's sarcoma using human anti-CD99 targeted hybrid polymerization liposomal nanoparticles

Most anticancer therapies are unspecific and therefore inevitably lead to off-target toxicity. To overcome these shortcomings, targetable hybrid polymerization liposomal nanoparticles (HPLNs) have been invented. Multiple innovative and proprietary technologies have been developed to enable creation of this unique form of nanoparticle therapy, including the use of cross linked lipids to improve both stability and bioavailability, modified polyethylene glycol (PEG) for both ‘stealthiness' (to prevent immune response to the nanoparticle) and for covalent attachment of targeting molecules such as tumor specific antibodies or peptides. Our present study showed the superior efficacy of human anti-CD99 targeted HPLNs in the treatment of Ewing sarcoma. Human monoclonal anti-CD99 antibody-targeted HPLNs encapsulating irinotecan (CD99-HPLN/Ir) can efficiently reach implanted Ewing sarcoma tumors in xenograft mice and dramatically reduce and/or eliminate the tumor burden. Complete tumor ablation has been observed at doses as low as 1 mg irinotecan/kg, treated twice per week. In other cases, animals who failed untargeted (HPLN/Ir) treatment showed complete tumor ablation after ‘salvage' treatment with CD99-HPLN/Ir. Our CD99 targeted HPLN/irinotecan formulation, termed NV103 showed much better efficacy than the commercial untargeted liposomal irinotecan (Onivyde™) and doxorubicin (Doxil™). Toxic side effects, normally associated with systemic administration of free irinotecan, were minimized or undetectable. Our nanoparticles showed excellent bioavailability. Even the untargeted HPLN/Ir improve drug bioavailability six-fold in a comparison experiment with the drug in liposome form (Onivyde™), with no discernable systemic toxicity. Antibody targeting of the HPLN irinotecan formulation (NV103) improves the efficacy 12-fold, over the untargeted liposome form. In conclusion, this formulation may be effective for treatment of other CD99-expressing tumors like certain leukemias, lymphomas and glioma. Ultimately, after development of other tumor-specific targeting agents and varied encapsulated therapeutics, this technology can be usefully adapted for the treatment of other cancers as well. Citation Format: Hyunggyoo Kang, Jon Nagy, Timothy Triche. Targeted anticancer drug delivery to Ewing's sarcoma using human anti-CD99 targeted hybrid polymerization liposomal nanoparticles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018