Abstract 4475: Evaluation of targeted immunoliposomes encapsulating 4-N-hydroxylgemcitabine in EGFR-positive pancreatic cancer

Abstract Purpose: Pancreatic cancer (PCa) is a deadly malignancy that is challenging to treat. Gemcitabine (Gem) is a standard therapy in PCa treatment. Epidermal growth factor receptor (EGFR) is commonly overexpressed in PCa and contributes to tumor progression and metastasis. Gem is limited by its short half-life and metabolic instability. Our previous studies demonstrated that our modified Gem analog (GemAGY) had improved metabolic stability and anticancer activity compared to Gem. Targeted immunoliposomes have been developed to increase cellular uptake and accumulation in PCa. This study seeks to develop an EGFR-targeted immunoliposome with improved antitumor activity of Gem against PCa. Methods: EGFR antibody (cetuximab) was conjugated to a liposome encapsulating 4-N-hydroxylGemcitabine hydrochloride (GemAGY) called GemAGY-LnP. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the conjugation of the EGFR antibody to the liposome. GemAGY-LnP was characterized using the dynamic light scattering technique. MiaPaCa-2 spheroid cultures and patient derived xenograft (PDX) pancreatic tumor mouse models were treated with GemAGY-Lnp and Gemcitabine Hydrochloride (GemHCl). 3D cell viability assay was conducted using MiaPaCa-2 spheroids to evaluate the anticancer effects of GemAGY-LnP. Pharmacokinetics, biodistribution, and in vivo antitumor efficacy studies were conducted using PDX mouse models. Results: FTIR confirmed the successful conjugation of the EGFR antibody to the liposome. The mean particle size and zeta potential of GemAGY-LnP were 141.6 ± 40nm (Poly Dispersity Index = 0.15± 0.01) and -25.2 ± 0.04mV, respectively. The entrapment efficiency of GemAGY-Lnp was 66%. The half-maximal inhibitory concentration (IC50) value was significantly lower (6-fold lower) in GemAGY-LnP- treated MiaPaCa-2 spheroids (3.75±0.3µM) when compared to GemHCl-treated spheroids (24.12 ± 4.8µM) indicating that GemAGY-Lnp exhibited a higher cytotoxic effect when compared to GemHCl. The pharmacokinetics profile revealed that the area under the curve (AUC) of GemAGY-Lnp (52.70 ±0.05 μghr/mL) was over 15-fold higher than that of GemHCl (3.09±0.04) μghr/mL) while half-life of GemAGY-LnP (1.93 hr) was almost 4-fold higher than that of GemHCl (0.50 hr). In vivo studies showed that tumor growth inhibition in PDX pancreatic tumor mice treated with GemAGY-Lnp was significantly higher than in PDX mice treated with GemHCl (GemAGY-LnP vs GemHCl; p <0.0001). The biodistribution studies revealed a significantly higher GemAGY-Lnp accumulation in tumor relative to GemHCl. Conclusion: Our findings suggest that GemAGY-Lnp significantly increases the tumor accumulation of Gem, enhances the anticancer activity and improves Gem’s pharmacokinetic profile compared to GemHCl. GemAGY-LnP may potentially inhibit tumor growth when treating EGFR-positive pancreatic cancer. Citation Format: Joy Okoro, Raviteja Bulusu, Esther Frimpong, Saunjoo Yoon, Bo Han, Renee Reams, Xue Zhu, Edward Agyare. Evaluation of targeted immunoliposomes encapsulating 4-N-hydroxylgemcitabine in EGFR-positive pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4475.