Abstract 3206: Tumor-targeted nanoparticles for cancer therapy

Abstract Introduction: Untargeted cancer therapy is often toxic, limiting the maximum tolerated dose (MTD) and thus potential cure. Targeted therapy with antibody-drug conjugates (ADCs) has demonstrated greater efficacy, as with those directed at HER2 for triple negative breast cancer and other HER2 expressing tumors. However, ADC drug-antibody ratio (DAR) is limited, typically 3 to 1. In contrast, antibody-targeted nanoparticles deliver thousands of drug molecules per nanoparticle, with potentially greater anti-tumor effect. Experimental Procedures: Antibody targeted nanoparticles (TNP) were created that preferentially deliver cytotoxic molecules to tumor cells. TNPs were created with various antibodies and payloads and evaluated for their efficacy against 12 different adult and pediatric malignancies (see below), using tumor xenografts in NOG-SCID mice. Survival of control, free drug, and TNP treated animals was compared. MED was also determined. Non-tumor bearing animals treated at the same dose and schedule were evaluated for evidence of toxicity. PK/PD metrics were obtained and drug delivery to normal and tumor tissue was evaluated microscopically and by mass spectroscopy. Data: Plasma TNP drug levels persist for 48 hours, compared to free drug which is undetectable by 2 hours. Microscopically, nanoparticles accumulate in tumor tumor tissue but not normal tissue. Drug levels are typically 15 times higher in tumor tissue than normal tissue by quantitative mass spectroscopy. The minimum effective dose (MED) is reduced 25-fold for Ewing sarcoma, from 50 mg/kg to 2 mg/kg. TNPs also cross the blood-brain barrier (BBB), and were used to treat orthotopic GBM PDX xenografts, prolonging animal survival 3-fold over control or free drug treated animals. Ewing sarcoma, osteosarcoma, triple negative breast cancer, GBM, hepatoma, and adult ALL, bearing animals all showed complete tumor ablation and 100% survival when treated biweekly at 10mg/kg. Pancreatic, prostate, and ovarian Ca showed 100% survival in TNP treated mice after all control animals had died but remained tumor bearing with slow but progressive tumor growth when treated identically. Lung and colorectal Ca and melanoma bearing animals treated similarly with TNPs showed 50-80% survival at the time of control animal death. No animal in any study showed evidence of off-target toxicity. Conclusions: Tumor antigen targeted, cytotoxic molecule containing nanoparticles have been created that show broad utility in the treatment of at least a dozen different adult and pediatric cancers. Six of 12 types showed complete tumor ablation when treated at 10mg/kg biweekly injections, and the remainder showed enhanced anti-tumor effect and survival compared to free drug treatment. We conclude that use of tumor antigen targeted, small molecule cytotoxic containing nanoparticles results in dramatically enhanced tumor response and in many case, complete tumor ablation where the same free drug fails to do so. Citation Format: HyungGyoo Kang, Bryon Upton, Jon Nagy, Timothy Triche. Tumor-targeted nanoparticles for cancer therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 3206.