Challenges and Opportunities in the Oral Delivery of Recombinant Biologics

Advances in Oral Biomacromolecule Therapies for Metabolic Diseases

Metabolic diseases like obesity and diabetes are on the rise, and therapies with biomacromolecules (such as proteins, peptides, antibodies, and oligonucleotides) play a crucial role in their treatment. However, these drugs are traditionally injected. For patients with chronic diseases (e.g., metabolic diseases), long-term injections are accompanied by inconvenience and low compliance. Oral administration is preferred, but the delivery of biomacromolecules is challenging due to gastrointestinal barriers. In this article, we introduce the available biomacromolecule drugs for the treatment of metabolic diseases. The gastrointestinal barriers to oral drug delivery and strategies to overcome these barriers are also explored. We then discuss strategies for alleviating metabolic defects, including glucose metabolism, lipid metabolism, and energy metabolism, with oral biomacromolecules such as insulin, glucagon-like peptide-1 receptor agonists, proprotein convertase subtilisin/kexin type 9 inhibitors, fibroblast growth factor 21 analogues, and peptide YY analogues.

Preference for a Novel Oral Alternative to Parenterally Administered Medications

Background

Rani Therapeutics is developing a robotic pill (RP), an oral drug delivery platform called RaniPill™ that can deliver a number of biotherapeutics with high bioavailability; eliminating the need for injections. While patients in general prefer oral to injectable therapies, preference for a more frequent oral regimen compared to a less frequent injectable regimen is unknown. Two marketing surveys were conducted to gather data on preference for oral versus injectable therapies. A clinical study gathered data on participant preference for oral pills vs injections before and after swallowing a Mock-RP capsule.

Methods

A total of 1689 adults taking injections (mean duration 3-7 years) to treat endocrine or inflammatory conditions were anonymously surveyed online for their preference to administer/prescribe medications orally via the RP. In the clinical study, 150 participants currently taking injections for chronic conditions evaluated the swallowability of a Mock-RP and completed a questionnaire regarding their preferences.

Results

Majority of respondents surveyed stated they would be willing to convert to an oral alternative over their current parenteral therapy regardless of drug or disease. In the clinical study, all participants were able to swallow the Mock-RP and 91% indicated their preference for the oral route versus their current parenteral route of drug administration. Survey respondents and those in the clinical study using frequent injections were more willing to select a once-daily capsule compared to those injecting infrequently. Even study participants who inject infrequently (≥monthly: 80%) would prefer a once-daily pill over their injection regimen.

Conclusion

Patients taking injections and prescribing physicians strongly prefer oral dosing to parenteral administration of biologics even if dosing frequency with the oral option, such as the RP, is increased.

Rational design of soluble expressed human aldehyde dehydrogenase 2 with high stability and activity in pepsin and trypsin

Acetaldehyde dehydrogenase 2 (ALDH2) is a crucial enzyme in alcohol metabolism, and oral administration of ALDH2 is a promising method for alcohol detoxification. However, recombinant ALDH2 is susceptible to hydrolysis by digestive enzymes in the gastrointestinal tract and is expressed as inactive inclusion bodies in E. coli. In this study, we performed three rounds of rational design to address these issues. Specifically, the surface digestive sites of pepsin and trypsin were replaced with other polar amino acids, while hydrophobic amino acids were incorporated to reshape the catalytic cavity of ALDH2. The resulting mutant DE2-852 exhibited a 45-fold increase in soluble expression levels, while its stability against trypsin and pepsin increased by eightfold and twofold, respectively. Its catalytic efficiency (kcat/Km) at pH 7.2 and 3.2 improved by more than four and five times, respectively, with increased Vmax and decreased Km values. The enhanced properties of DE2-852 were attributed to the D457Y mutation, which created a more compact protein structure and facilitated a faster collision between the substrate and catalytic residues. These results laid the foundation for the oral administration and mass preparation of highly active ALDH2 and offered insights into the oral application of other proteins.

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.