Neovascular age-related macular degeneration (AMD) is treated with anti-VEGF intravitreal injections, which can cause geographic atrophy, infection, and retinal fibrosis. To minimize these toxicities, we developed a nanoparticle delivery system for recombinant Flt23k intraceptor plasmid (RGD.Flt23k.NP) to suppress VEGF intracellularly within choroidal neovascular (CNV) lesions in a laser-induced CNV mouse model through intravenous administration. In the current study, we examined the efficacy and safety of RGD.Flt23k.NP in mice. The effect of various doses was determined using fluorescein angiography and optical coherence tomography to evaluate CNV leakage and volume. Efficacy was determined by the rate of inhibition of CNV volume at 2 weeks post-treatment. RGD.Flt23k.NP had peak efficacy at a dose range of 30-60 μg pFlt23k/mouse. Using the lower dose (30 μg pFlt23k/mouse), RGD.Flt23k.NP safety was determined both in single-dose groups and in repeat-dose (three times) groups by measuring body weight, organ weight, hemoglobin levels, complement C3 levels, and histological changes in vital organs. Neither toxicity nor inflammation from RGD.Flt23k.NP was detected. No side effect was detected on visual function. Thus, systemic RGD.Flt23k.NP may be an alternative to standard intravitreal anti-VEGF therapy for the treatment of neovascular AMD.

PURPOSE. We determine whether intravitreal angiopoietin-1 combined with the short coiledcoil domain of cartilage oligomeric matrix protein by adeno-associated viral serotype 2 (AAV2.COMP-Ang1) delivery following the onset of vascular damage could rescue or repair damaged vascular beds and attenuate neuronal atrophy and dysfunction in the retinas of aged diabetic mice. METHODS. AAV2.COMP-Ang1 was bilaterally injected into the vitreous of 6-month-old male Ins2 Akita mice. Age-matched controls consisted of uninjected C57BL/6J and Ins2 Akita males, and of Ins2 Akita males injected with PBS or AAV2.REPORTER (AcGFP or LacZ). Retinal thickness and visual acuity were measured in vivo at baseline and at the 10.5-month endpoint. Ex vivo vascular parameters were measured from retinal flat mounts, and Western blot was used to detect protein expression. RESULTS. All three Ins2 Akita control groups showed significantly increased deep vascular density at 10.5 months compared to uninjected C57BL/6J retinas (as measured by vessel area, length, lacunarity, and number of junctions). In contrast, deep microvascular density of Ins2 Akita retinas treated with AAV2.COMP-Ang1 was more similar to uninjected C57BL/6J retinas for all parameters. However, no significant improvement in retinal thinning or diabetic retinopathy-associated visual loss was found in treated diabetic retinas. CONCLUSIONS. Deep retinal microvasculature of diabetic Ins2 Akita eyes shows late stage changes consistent with disorganized vascular proliferation. We show that intravitreally injected AAV2.COMP-Ang1 blocks this increase in deep microvascularity, even when administered subsequent to development of the first detectable vascular defects. However, improving vascular normalization did not attenuate neuroretinal degeneration or loss of visual acuity. Therefore, additional interventions are required to address neurodegenerative changes that are already underway.

e16191 Background: Biliary tract cancers are aggressive tumors with limited treatment options. Several ongoing clinical trials are currently exploring role of immune therapy in advanced BTC. Programmed death-ligand 1 (PD-L1), tumor mutational burden (TMB), and microsatellite instability (MSI) are commonly used immune related-biomarkers. Herein, we analyzed the TMB, MSI and PD-L1 expression in advanced BTC. Methods: We retrospectively evaluated the association of TMB, MSI and PD-L1 expression with survival and related treatment outcomes. Results: The immune mediated biomarkers were reported in a total of 62 BTC patients (pts). The mean age of the pts is 73 (range 32-83) years, with predominant females (59%) and Caucasians (82%). The most common histology noted was intrahepatic cholangiocarcinoma (67%) followed by extrahepatic cholangiocarcinoma (18%) and gallbladder carcinoma (15%). Approximately, 40% received 2 or more lines of therapy while 20% of patients didn’t receive any treatment and over. The treatment regimen included gemcitabine-based regimen (35%), 5FU based regimen (18%), immune therapy (15%) and targeted therapy (6%). The TMB was low in 52 pts (83%), intermediate 7 pts (11%) and high in 2 pts (3%). MSI is stable in 55 pts (89%) and PD-L1 expression is negative in 29 pts (47%) and positive in 23 pts (37%). Conclusions: Our data suggests the BTC’s have in general low TMB, are microsatellite stable and have low PD-L1 expression. The potential prognostic and predictive value of these immune related- biomarkers need to be validated in larger studies.

No abstract