A modular nucleic acid-albumin biomolecular platform for multifunctional drug designs

The nanomedicine field has seen a paradigm shift towards multifunctional drug designs to maximise drug efficacy. Assembly of functionalised oligonucleotide (ODN) modules onto an albumin scaffold is an attractive solution offering a technological advancement in albumin-based drug delivery we apply in this work for a T-Cell Engager (TCE) and Immune Checkpoint Inhibitor (ICI) immuno-oncology combination. The "plug-and-play" modular approach was used to incorporate an anti-programmed cell death protein ligand 1 (anti-PD-L1) nanobody-ODN module onto a bispecific anti-EGFR x anti-CD3 scFv-albumin TCE fusion. Cys34 ODN site-specific conjugation on albumin allowed subsequent base-driven annealing of the complementary anti-PD-L1 nanobody-ODN module offering an easy and versatile alternative to established protein engineering approaches. The biomolecular components elements demonstrated effective binding of cellular targets in vitro, efficient PD-1/PD-L1 axis blockade and enhanced T-cell mediated cancer cell killing compared to single or separate combined treatments. Modular assembly on an albumin scaffold engineered with high neonatal Fc receptor affinity increased the circulatory half-life in humanised FcRn/albumin mice from 18.8 h to 26.6 h compared to wild type albumin sequences. This biomolecular assembly reflects the transition in the field towards multifunctional platforms exemplified in this work with an ICI and TCE combination promoting application for a range of functionalities and drug class combinations and offering programable half-life through inclusion of albumin sequences with different FcRn affinities.