Project summary/abstract
Modern medicine has created precision drugs blocking a single therapeutic target like TGF-ß with high affinity
and specificity. Yet treating lung diseases remains challenging in part because lung microvascular endothelium
represents a key restrictive barrier to effective drug delivery. Current systemic therapeutics rely solely on
convection and diffusion to extravasate passively into the tissue interstitium where disease targets and cells
can readily be reached and directly treated. The goal of this research proposal is to design, develop and test a
novel drug delivery system for immunotherapeutics that overcomes this key barrier by targeting caveolae to
facilitate active and specific transcytosis into lungs after intravenous injection. The ideal is to deliver the entire
therapeutic dose inside the lung tissue with all other tissues minimally exposed. We attempt to approach this
ideal by achieving robust transendothelial pumping precisely into lung tissue to comprehensively block the
therapeutic target TGF-ß, which regulates inflammation and remodeling in diseased tissues. Because TGF-ß
also exerts various homeostatic effects in many organs, caution is necessary when systemic targeting of its
function is attempted. Precision lung targeting proposed here will maximize efficacy and therapeutic indices by
minimizing dosages, eliminating toxicities, and reducing cost of treatment. To that end, we have genetically
engineered the first “dual precision” immunotherapeutics, namely bispecific antibodies in quad format with one
arm pair mediating precise binding/delivery to and penetration of lung tissue via caveolae pumping and the
other pair constituting the precision therapeutic modality that blocks TGF-ß effector function. Active
transendothelial delivery improved precision lung targeting by 100-fold over standard passive transport.
Delivering most of the injected dose into lungs within 1 hour enhanced therapeutic potency by >1000-fold in a
rat pneumonitis model. Now our goal is to expand this promising preliminary work and further improve and
rigorously test this drug delivery system to treat key lung diseases at distinct stages ranging from early acute
inflammation to chronic and progressive fibrosis. We will optimize lung targeting of our dual precision
immunotherapeutics and study their specific lung delivery, penetration, accumulation, localization, and
therapeutic impact in rats using multiple imaging techniques (SPECT-CT, IVM, EM, and IHC). Therapeutic
effects will be assessed in a rat bleomycin model that reproduces pathological hallmarks of many fatal human
diseases including ALI, ARDS, COVID, pneumonias, and fibrosis. Our specific aims are: 1) to engineer and
evaluate distinct caveolae-targeted antibody constructs for precision active delivery into normal lung tissue, 2)
to quantify targeting and optimize delivery of bispecific immunotherapeutics in lung disease, 3) to test efficacy
of bispecific immunotherapeutics to ameliorate lung disease and block TGF-ß pathways. This work sets a
foundation for caveolae-targeted therapies and could begin a paradigm shift from passive to active drug
delivery for many diseases.