Targeted Nanofitin-drug Conjugates Achieve Efficient Tumor Delivery and Therapeutic Effect in an EGFRpos Mouse Xenograft Model

Complete preclinical evaluation of the novel antibody mimetic Nanofitin-IRDye800CW for diverse non-invasive diagnostic applications in the management of HER-2 positive tumors

There are well-known limitations associated to the use of antibodies in the non-invasive detection of HER-2 expression. In fact, current procedures recommended for diagnostic purposes of HER-2 status are still invasive techniques. Here, a novel, smaller diagnostic probe, the anti-HER-2 Nanofitin conjugated to the fluorophore IRDye800CW (NF-800), underwent an in vitro/in vivo proof of concept study by Optical Imaging. NF-800 showed high affinity and specificity for the cellular target, and the ability to internalize into HER-2 positive cells. By ex vivo analysis, NF-800 showed a selective tumor accumulation in xenograft tumor models, and also a good tumor targeting efficacy in translational preclinical setups, such as orthotopic and patient-derived xenograft (PDX) models. In the latter, NF-800 was compared to the anti-HER-2 antibody Trastuzumab, displaying a large diagnostic advantage. Interestingly, NF-800 did not seem to share the same binding site with Trastuzumab and Pertuzumab, opening specific theragnostic opportunities for NF-800 in combination with standard-of-care antibodies.

Enhancing Oral Delivery of Biologics: A Non-Competitive and Cross-Reactive Anti-Leptin Receptor Nanofitin Demonstrates a Gut-Crossing Capacity in an Ex Vivo Porcine Intestinal Model

Biotherapeutics exhibit high efficacy in targeted therapy, but their oral delivery is impeded by the harsh conditions of the gastrointestinal (GI) tract and limited intestinal absorption. This article presents a strategy to overcome the challenges of poor intestinal permeability by using a protein shuttle that specifically binds to an intestinal target, the leptin receptor (LepR), and exploiting its capacity to perform a receptor-mediated transport. Our proof-of-concept study focuses on the characterization and transport of robust affinity proteins, known as Nanofitins, across an ex vivo porcine intestinal model. We describe the potential to deliver biologically active molecules across the mucosa by fusing them with the Nanofitin 1-F08 targeting the LepR. This particular Nanofitin was selected for its absence of competition with leptin, its cross-reactivity with LepR from human, mouse, and pig hosts, and its shuttle capability associated with its ability to induce a receptor-mediated transport. This study paves the way for future in vivo demonstration of a safe and efficient oral-to-systemic delivery of targeted therapies.