Abstract 13307: An Oral Antisense Oligonucleotide for PCSK9 Inhibition in Humans

Current PCSK9 inhibitors are administered via subcutaneous (SC) injection. Here, we present a highly potent, chemically modified PCSK9 antisense oligonucleotide (ASO) with potential for oral delivery. Past attempts at oral delivery using earlier ASO chemistries and intestinal permeation enhancers provided encouraging data, suggesting that improving potency of the ASO could make oral delivery a reality. The constrained ethyl chemistry and liver targeting enabled by tri-antennary N -acetyl galactosamine (GalNAc) conjugation make this ASO highly potent. A single SC dose of 90 mg reduces PCSK9 by >90% in humans with elevated LDL-C (A), and a once monthly SC dose of 25 mg ([20, 30], 90% CI) is predicted to reduce PCKS9 by 80% at steady-state. To investigate the feasibility of oral administration, we developed an oral solid tablet wherein the ASO is co-formulated with a transient permeation enhancer. Repeated oral daily dosing of tablets to dogs resulted in a bioavailability of 7% in the liver (target organ), approximately 5-fold greater than the plasma bioavailability (B). Favourable liver uptake following oral administration is supported by similar bioavailability in plasma and kidney. Since the ASO is not active in rodents or dogs, we used a rat-specific GalNAc- Malat-1 ASO with the same chemistry to confirm target engagement. Intrajejunal administration resulted in ≥78% mRNA knockdown in the liver for single doses of 3-40 mg/kg. A monkey tolerability study of the PCSK9 ASO further supports oral feasibility with all tested doses (28-56 mg/day) significantly reducing LDL-C already after 7 days of daily oral dosing. Based on available animal and human data, and an assumption of 5% oral bioavailability in humans, a daily dose of 15 mg ([10, 20], 90% CI) in man is predicted to reduce PCSK9 in plasma by 80% at steady-state. This supports the development of the compound for subcutaneous and oral administration to treat dyslipidemia.

From Farm to Pharmacy: Strawberry-Enabled Oral Delivery of Protein Drugs

Although oral drug delivery is preferred by patients, it is not possible for proteins because the gastrointestinal tract is not sufficiently permeable. To enable the non-toxic oral uptake of protein drugs, we investigated plant-based foods as intestinal permeation enhancers, hypothesizing that compounds found in food would be well-tolerated by the gastrointestinal tract. Following a screen of over 100 fruits, vegetables, herbs, and fungi, we identified strawberry as a potent enhancer of macromolecular permeability in vitro and in mice. Natural product chemistry techniques identified pelargonidin, an anthocyanidin, as the active compound. In mice, insulin was orally administered with pelargonidin to induce sustained pharmacodynamic effects with doses as low as 1 U/kg and bioactivity of over 100% relative to the current gold standard of subcutaneous injection. Pelargonidin-induced permeability was reversible within two hours of treatment, and one month of daily dosing did not adversely affect mice as determined by weight tracking, serum concentrations of inflammatory markers, and tight junction gene expression. Results underscore the utility of plant-based foods in biomedical applications and demonstrate pelargonidin as an especially potent enhancer for the oral delivery of biologics.