Light-Activated SIte-Specific Conjugation (LASIC) to accelerate clinical translation of catheter-directed antibody-drug-conjugate labeled theranostic microbubbles in an Oncopig liver tumor model

PROJECT SUMMARY While conventionally known as contrast agents for diagnostic ultrasound, gas-encapsulated microbubbles can also be functionalized with targeting antibodies and therapeutic payloads. This unique delivery mechanism allows for improved therapeutic index in difficult-to-reach locations, minimizing the risk for off-target effects. However, the potential of microbubble theranostic agents has not yet been fully realized because of current limitations in conjugating antibodies and therapeutic agents to the microbubble itself. These limitations include difficulties in conjugating the antibodies in the right alignment on the microbubble while preserving microbubble integrity. It is also unclear what the pharmacokinetic characteristics of the theranostic microbubbles will be in a clinically-relevant large animal model. We plan to overcome these limitations using a novel site-specific labeling technique known as Light Activated Site-Specific Conjugation (LASIC) technology. Leveraging LASIC to attach both targeting antibodies and therapeutic payloads will streamline the theranostic microbubble manufacturing process, facilitating its translation into the clinical population. With successful LASIC-optimization of microbubbles, the biodistribution of these microbubbles will be further improved via image-guided catheter delivery. This project will be conducted via 3 aims: 1) Creating targeted microbubbles using LASIC technology: We will test the feasibility of LASIC on commercially available avidin-coated, and then the less immunogenic azido-lipid-based microbubbles. Efficacy of microbubble-cell binding will be evaluated using in vitro assays and ultrasound phantoms. We will then 2) Generate theranostic microbubbles using LASIC to attach therapeutic payloads to the microbubbles. In this aim we will also augment microbubble payload release via non-invasive sonoporation, using in vitro techniques to optimize drug delivery. Lastly, we will 3) validate the safety and pharmacokinetic profile of the LASIC-optimized microbubbles large animal tumor model, also known as the Oncopig. The microbubbles will be delivered via a clinically relevant image-guided catheter, allowing for maximum therapeutic index in the target tumor. The results of this project will have significant implications for the translatability of microbubble platforms for theranostic purposes. By minimizing disruption of the phospholipid shell, LASIC can potentially revolutionize the way microbubbles are currently conjugated. The potential implications of this research extend well beyond the immediate impact of microbubble conjugation chemistry, paving the way for future advancement in theranostic agents, image-guided interventions, and large animal validation modeling.