Drug delivery trends in clinical trials and translational medicine: growth in biologic molecule development and impact on rheumatoid arthritis, Crohn's disease, and colitis

Sodium deoxycholate/TRIS-based hydrogels for multipurpose solute delivery vehicles: Ambient release, drug release, and enantiopreferential release

Herein, we report the investigation of sodium deoxycholate (NaDC)/TRIS-based hydrogels as delivery vehicles for a broad range of applications. Three hydrogel formulations were chosen for unique rheological behaviors that suggest a change in internal hydrogel structure with the application of a shear force. In this work, we compare solute release from sheared and non-sheared hydrogels in order to explore the effect of shear force on structure and release kinetics. It was found that the application of a shear force, in addition to changes in temperature, drug solubility, drug concentration, and hydrogel formulation each affected the amount of solute ultimately released from a hydrogel system. Moreover, the use of the inherent chirality of the hydrogel network for enantio-preferential drug release was also explored. We show significant enantio-preference in the release of model drugs tryptophan and ibuprofen from the hydrogel network. Furthermore, hydrophobic domains within the hydrogel network were exploited to enable ibuprofen loading at ten times the maximum water solubility. Retention of enantio-preference was observed at this higher ibuprofen concentration. Cyclodextrin modification to the hydrogel matrix allowed for enantio-preferential inversion which is an unprecedented observation.

Biology of anti-TNF agents in immune-mediated inflammatory diseases: therapeutic implications

Biologics are increasingly being used to modify the course of immune-mediated inflammatory diseases. Some main agents are monoclonal antibodies and a fusion-protein that target TNF. This group includes adalimumab, infliximab, certolizumab pegol, golimumab and etanercept. Although the efficacy of anti-TNFs is supported by numerous randomized clinical trials, their pharmacokinetics depend on many factors, in particular immunogenicity, which can cause marked and rapid clearance and a consequent decrease in efficacy. Kinetics involve receptors that recognize the Fc fragment of the antibody and are responsible for various processes. Pharmacological advances permit optimizing the pharmacokinetics of anti-TNFs. In this review, we examine the kinetics of anti-TNF biologics, and consequent therapeutic implications, and overview some latest developments in the field. First draftsubmitted: 17 May 2016; Accepted for publication: 15 September2016; Published online: 14 October 2016.

Polymyxins Facilitate Entry into Mammalian Cells

Polymyxin and guanidinylated polymyxin effectively deliver large biomolecules and liposomal assemblies into mammalian cells.

Polymyxin B is an antibiotic used against multi-resistant Gram negative infections, despite observed nephrotoxicity. Here we report the synthesis of functionalized derivatives of polymyxin B and its per-guanidinylated derivative in order to further explore the structural requirements necessary to facilitate uptake of the antibiotic into mammalian cells. We also investigate the possibility of using these novel scaffolds as molecular transporters. At nanomolar concentrations, both are capable of delivering large cargo (>300 kDa) into living cells. Their uptake depends exclusively on cell surface heparan sulfate. Mechanistic studies indicate these novel transporters are internalized through caveolae-mediated pathways and confocal microscopy show colocalization with lysosomes. The polymyxin-based transporters demonstrate cytosolic delivery through the delivery of a ribosome-inactivating protein. Furthermore, the natural polymyxin scaffold can be incorporated into liposomes and enhance their intracellular uptake. In addition to demonstrating the ability of the polymyxin scaffold to facilitate internalization into mammalian cells, these observations suggest the potential use of polymyxin and guanidinopolymyxin for intracellular delivery.

The effects of arginine glutamate, a promising excipient for protein formulation, on cell viability: Comparisons with NaCl

The effects of an equimolar mixture of l-arginine and l-glutamate (Arg·Glu) on cell viability and cellular stress using in vitro cell culture systems are examined with reference to NaCl, in the context of monoclonal antibody formulation. Cells relevant to subcutaneous administration were selected: the human monocyte cell line THP-1, grown as a single cell suspension, and adherent human primary fibroblasts. For THP-1 cells, the mechanism of cell death caused by relatively high salt concentrations was investigated and effects on cell activation/stress assessed as a function of changes in membrane marker and cytokine (interleukin-8) expression. These studies demonstrated that Arg·Glu does not have any further detrimental effects on THP-1 viability in comparison to NaCl at equivalent osmolalities, and that both salts at higher concentrations cause cell death by apoptosis; there was no significant effect on measures of THP-1 cellular stress/activation. For adherent fibroblasts, both salts caused significant toxicity at ~400 mOsm/kg, although Arg·Glu caused a more precipitous subsequent decline in viability than did NaCl. These data indicate that Arg·Glu is of equivalent toxicity to NaCl and that the mechanism of toxicity is such that cell death is unlikely to trigger inflammation upon subcutaneous injection in vivo.

Therapy of inflammatory bowel disease: what to expect in the next decade

PURPOSE OF REVIEW

The increased understanding of the molecular mechanisms that are responsible for inflammatory bowel disease (IBD) has led to a wide range of potential therapeutic targets for this condition. Physicians treating individuals with Crohn's disease and ulcerative colitis have a growing armamentarium of options to choose from in managing these patients. This article aims to summarize the relevant literature in the area of emerging therapy in IBD.

RECENT FINDINGS

The widespread use of antitumor necrosis factor medications brought a landmark change in the treatment of IBD. More recently, several drugs have been shown to provide benefit in IBD in phase III studies by blocking other antiinflammatory pathways. The most likely new medications that will be available include vedolizumab for ulcerative colitis and ustekinumab for Crohn's disease, which target cellular adhesion and inflammatory cell signaling, respectively. Other promising drugs focus on blockade of Janus kinase, inhibition of various chemokines, and biologic therapy such as hematopoietic stem cell transplants and mesenchymal cell infusions.

SUMMARY

The growing understanding of the pathogenesis of IBD has led to new molecular targets for therapy. Over the next decade, the number of treatments available will grow, targeting cellular adhesion, protein regulation, inflammatory signal pathways, and immune tolerance.

Fifteen years of cell-penetrating, guanidinium-rich molecular transporters: basic science, research tools, and clinical applications

All living systems require biochemical barriers. As a consequence, all drugs, imaging agents, and probes have targets that are either on, in, or inside of these barriers. Fifteen years ago, we initiated research directed at more fully understanding these barriers and at developing tools and strategies for breaching them that could be of use in basic research, imaging, diagnostics, and medicine. At the outset of this research and now to a lesser extent, the "rules" for drug design biased the selection of drug candidates mainly to those with an intermediate and narrow log P. At the same time, it was becoming increasingly apparent that Nature had long ago developed clever strategies to circumvent these "rules." In 1988, for example, independent reports documented the otherwise uncommon passage of a protein (HIV-Tat) across a membrane. A subsequent study implicated a highly basic domain in this protein (Tat49-57) in its cellular entry. This conspicuously contradictory behavior of a polar, highly charged peptide passing through a nonpolar membrane set the stage for learning how Nature had gotten around the current "rules" of transport. As elaborated in our studies and discussed in this Account, the key strategy used in Nature rests in part on the ability of a molecule to change its properties as a function of microenvironment; such molecules need to be polarity chameleons, polar in a polar milieu and relatively nonpolar in a nonpolar environment. Because this research originated in part with the protein Tat and its basic peptide domain, Tat49-57, the field focused heavily on peptides, even limiting its nomenclature to names such as "cell-penetrating peptides," "cell-permeating peptides," "protein transduction domains," and "membrane translocating peptides." Starting in 1997, through a systematic reverse engineering approach, we established that the ability of Tat49-57 to enter cells is not a function of its peptide backbone, but rather a function of the number and spatial array of its guanidinium groups. These function-oriented studies enabled us and others to design more effective peptidic agents and to think beyond the confines of peptidic systems to new and even more effective nonpeptidic agents. Because the function of passage across a cell membrane is not limited to or even best achieved with the peptide backbone, we referred to these agents by their shared function, "cell-penetrating molecular transporters." The scope of this molecular approach to breaching biochemical barriers has expanded remarkably in the past 15 years: enabling or enhancing the delivery of a wide range of cargos into cells and across other biochemical barriers, creating new tools for research, imaging, and diagnostics, and introducing new therapies into clinical trials.

Trends in translational medicine and drug targeting and delivery: new insights on an old concept-targeted drug delivery with antibody-drug conjugates for cancers

According to the JPS Drug Delivery Clinical Trials Database (jpharmscidatabase.org), 37,738, 14,104, and 8060 clinical trials are registered to evaluate (1) drug delivery technology, (2) biomolecule platform, and (3) drug metabolism and pharmacokinetic (PK)-pharmacodynamic (PD) interactions. These numbers represent a 19%-29% increase since 2012. Within biomolecules in clinical testing, antibodies constitute the majority and approximately 6% carry drug conjugates. Paul Ehrlich introduced the antibody-drug conjugate or "magic bullet" concept about a century ago. A monoclonal antibody (mAb)-drug conjugate Mylotarg was licensed for treating cancer in 2000 and exhibits significant liver toxicity and immune hypersensitivity. Plasma drug instability and a bacterial-derived drug may be partly to blame. Progress in antibody-drug conjugation chemistry, understanding how biologic systems respond to antibody-drug conjugates, and unwavering efforts of scientists have enabled successful development of highly potent and effective second-generation antibody-drug conjugates. With the approval of Adcetris for lymphoma in 2011 and Kadcyla in 2013, about a twofold to fourfold gain in cancer response rate is attributed to drug conjugates. With a demonstrated higher safety profile, many more antibody-drug conjugates are in development. The clinical success of Adcetris and Kadcyla has raised hope that antibody-guided "drug bullets" may be truly "magical" in leading to a cure for cancer.

A TLR4-interacting peptide inhibits lipopolysaccharide-stimulated inflammatory responses, migration and invasion of colon cancer SW480 cells

Inflammation is a major risk factor for carcinogenesis in patients affected by chronic colitis, yet the molecular mechanisms underlying the progression from chronic inflammation to cancer are not completely understood. Activation of the Toll-like receptor 4 (TLR4)-NFκB signaling axis is associated with inflammation. Thus, we hypothesized that inhibition of TLR4-NFκB signaling might help in limiting inflammatory responses and inflammation-induced oncogenesis. In this work, we studied the effects of a TLR4-interacting surfactant protein A-derived (SPA4) peptide on lipopolysaccharide (LPS)-induced TLR4-NFκB signaling and cancer progression. We first characterized this peptide for its ability to bind the TLR4 ligand-LPS and for physico-chemical characteristics. Inflammation was induced by challenging the colon cancer SW480 cells with Escherichia coli LPS. Cells were then treated with varying amounts of the SPA4 peptide. Changes in the expression of TLR4, interleukin (IL)-1β and IL-6, in intracellular NFκB-related signal transducers (IKBα, p65, phosphorylated IKBα, phosphorylated p65, RelB, COX-2) as well as in the transcriptional activity of NFκB were studied by immunocytochemistry, immunoblotting and NFκB reporter assay, respectively. Simultaneously, the effects on LPS-induced cell migration and invasion were determined. We found that the SPA4 peptide does not bind to LPS. Rather, its binding to TLR4 inhibits the LPS-induced phosphorylation of p65, production of IL-1β and IL-6, activity of NFκB, migration and invasion of SW480 cells. In conclusion, our results suggest that the inhibition of TLR4-NFκB signaling by a TLR4-binding peptide may help for the treatment of chronic inflammation and prevention of inflammation-induced cancer in patients with colitis.