Analytical comparability demonstrated for an IgG4 molecule, inclacumab, following transfer of manufacturing responsibility from Roche to Global Blood Therapeutics.

BACKGROUND: Inclacumab is a recombinant, fully human, immunoglobulin IgG4 monoclonal antibody that selectively binds to P-selectin. Initially discovered and developed by Roche through phase 2 clinical studies in peripheral arterial disease and coronary artery disease, inclacumab has been in-licensed by Global Blood Therapeutics (GBT) as a potential treatment to reduce the frequency of vaso-occlusive crises in individuals with sickle cell disease. RESEARCH DESIGN AND METHODS: GBT sought to demonstrate the analytical comparability between material produced by Roche and material produced by GBT to ensure that no meaningful differences in identity, safety, purity, potency, or bioavailability exist between the GBT and Roche lots. RESULTS: Inclacumab samples produced by GBT were found to be comparable to the Roche v0.2 inclacumab samples based on (1) comparable primary and higher-order structures; (2) comparable purity profiles; (3) comparable potency, in vitro functional activities, and in vivo plasma exposures and pharmacokinetic profiles; and (4) comparable degradation patterns and kinetics under forced degradation conditions. CONCLUSIONS: Based on the design of this comparability study and the results obtained, the US Food and Drug Administration approved the changes to the manufacturing process and gave clearance for GBT to proceed with phase 3 clinical trials.

Modeling the Kinetics of Lipid-Nanoparticle- Mediated Delivery of Multiple siRNAs to Evaluate the Effect on Competition for Ago2.

Drug combinations can improve the control of diseases involving redundant and highly regulated pathways. Validating a multi-target therapy early in drug development remains difficult. Small interfering RNAs (siRNAs) are routinely used to selectively silence a target of interest. Owing to the ease of design and synthesis, siRNAs hold promise for combination therapies. Combining siRNAs against multiple targets remains an attractive approach to interrogating highly regulated pathways. Currently, questions remain regarding how broadly such an approach can be applied, since siRNAs have been shown to compete with one another for binding to Argonaute2 (Ago2), the protein responsible for initiating siRNA-mediated mRNA degradation. Mathematical modeling, coupled with in vitro and in vivo experiments, led us to conclude that endosomal escape kinetics had the highest impact on Ago2 depletion by competing lipid-nanoparticle (LNP)-formulated siRNAs. This, in turn, affected the level of competition observed between them. A future application of this model would be to optimize delivery of desired siRNA combinations in vitro to attenuate competition and maximize the combined therapeutic effect.

Mathematical Modeling: A Tool for Optimization of Lipid Nanoparticle-Mediated Delivery of siRNA.

Lipid nanoparticles (LNPs) have been used to successfully deliver small interfering RNAs (siRNAs) to target cells in both preclinical and clinical studies and currently are the leading systems for in vivo delivery. Here, we propose the use of an ordinary differential equation (ODE)-based model as a tool for optimizing LNP-mediated delivery of siRNAs. As a first step, we have used a combination of experimental and computational approaches to develop and validate a mathematical model that captures the critical features for efficient siRNA-LNP delivery in vitro. This model accurately predicts mRNA knockdown resulting from novel combinations of siRNAs and LNPs in vitro. As demonstrated, this model can be effectively used as a screening tool to select the most efficacious LNPs, which can then further be evaluated in vivo. The model serves as a starting point for the future development of next generation models capable of capturing the additional complexity of in vivo delivery.

Chemoenzymatic synthesis of oligohyaluronan-lipid conjugates.

Herein, we describe an efficient and high-yielding method to synthesize hyaluronan oligosaccharide-lipid conjugates. This strategy is based on first covalently attaching diphytanoyl glycerophosphatidylethanolamine (DiPhPE) to commercially available high molecular weight hyaluronic acid (HA), via the carboxylate group of the glucuronic acid using carbodiimide chemistry. The HA-lipid conjugate mixture is then digested with bovine testicular hyaluronidase to yield HA-DiPhPE conjugates that have a narrow distribution of moderately sized HA oligosaccharides. These HA-lipid conjugates can be incorporated into liposomes or micelles to selectively target CD44 that is overexpressed on many cancer or cancer initiating cells.

Lipid nanoparticle purification by spin centrifugation-dialysis (SCD): a facile and high-throughput approach for small scale preparation of siRNA-lipid complexes.

This paper describes the use of spin centrifugation-dialysis (SCD) for small-scale concentration/purification of siRNA-lipid complexes designed for use as therapeutic agents for gene silencing. SCD consists of a two-step method for concentration, filtration and buffer exchange of lipid nanoparticles (LNP) to provide a homogeneous preparation suitable for injection. Here, we compare SCD with the more traditionally used tangential flow filtration (TFF), and demonstrate the physicochemical and biological comparability of LNPs produced with both methods. TFF is a highly scalable method used in both developmental and production applications, but is limited in terms of miniaturization. In contrast to TFF, SCD is faster, less expensive, and requires less oversight for assembling LNPs for small-scale applications, such as target screening both in vitro and in vivo. The finding that SCD is a viable method for filtering LNPs in a manner similar to TFF, producing particles with comparable properties and biological activity, is significant given the complexity and sensitivity of LNPs to processing conditions.

Glycobiology of the Leishmania parasite and emerging targets for antileishmanial drug discovery.

IMPORTANCE OF THE FIELD: Parasitic diseases that pose a threat to human life include leishmaniasis - caused by protozoa of Leishmania species. Existing drugs have limitations due to deleterious side effects like teratogenicity and factors like cost and drug resistance, thus furthering the need to develop this area of research. AREAS COVERED IN THIS REVIEW: We came across drug targets, very recently characterised, cloned and validated by genomics and bioinformatics. We bring these promising drug targets into focus so that they can be explored to their fullest. WHAT THE READER WILL GAIN: In an effort to bridge the gaps between existing knowledge and future prospects of drug discovery, we found interesting studies validating drug targets and paving the way for better experiments to be designed. In a few cases, novel pathways have been characterized, while in others, well established pathways when probed further, led to the discovery of new drug targets. TAKE HOME MESSAGE: The review constitutes a comprehensive report on upcoming drug targets, with emphasis on glycosylphosphatidylinositol (GPI)-anchored glycoconjugates along with related biochemistry of enolase, glycosome and purine salvage pathways, as we strive to bring ourselves a step closer to being able to combat this deadly disease.

Efficient synthesis of an aldehyde functionalized hyaluronic acid and its application in the preparation of hyaluronan-lipid conjugates.

An efficient method to synthesize hyaluronan oligosaccharide lipid conjugates is described. This strategy is based on the introduction of a double bond in the glucuronic acid of the hyaluronic acid (HA), by the biodegradation of HA with hyaluronate lyase, followed by the generation of a free aldehyde group at the nonreducing end of hyaluronic acid via ozonolysis and the subsequent reduction of the generated ozonide. The resulting aldehyde-functionalized HA is then coupled to dipalmitoyl phosphatidylethanolamine (DPPE) using reductive amination chemistry. This methodology can be extended to link molecules such as biotin, polymers, or proteins to HA for numerous applications in drug delivery and in the creation of biocompatible materials for tissue repair and engineering.

1-Oxabicyclic beta-lactams as new inhibitors of elongating MPT--a key enzyme responsible for assembly of cell-surface phosphoglycans of Leishmania parasite.

New iminosugars (1-oxabicyclic beta-lactam disaccharides) have been synthesized as inhibitors of elongating alpha-D-mannosyl phosphate transferase (eMPT), a key enzyme involved in the iterative biosynthesis of cell-surface phosphoglycans of the Leishmania parasite. The design is based on a transition-state model for this remarkable enzyme that transfers intact alpha-D-mannosyl-phosphate from GDP-Man. Since these phosphoglycans are unique to Leishmania and are essential for its infectivity and survival, their biosynthetic pathway has emerged as a novel target for anti-leishmanial drug and vaccine design.

Iterative synthesis of Leishmania phosphoglycans by solution, solid-phase, and polycondensation approaches without involving any glycosylation.

A general strategy (solution, solid-phase, and polycondensation) for the synthesis of antigenic phosphoglycans (PG) of the protozoan parasite Leishmania is presented. Phosphoglycans constitute the variable structural and functional domain of major cell-surface lipophosphoglycan (LPG) and secreted proteophosphoglycan (PPG), the molecules involved in infectivity and survival of the Leishmania parasite inside human macrophages. We have shown that the chemically labile, anomerically phosphodiester-linked phosphoglycan repeats can be assembled in an iterative and efficient manner from a single key intermediate, without involving any glycosylation steps. Furthermore, the phosphoglycan chain can be extended toward either the nonreducing (6'-OH) or the reducing (1-OH) end. We also describe a new and efficient solid-phase methodology to construct phosphoglycans based on design and application of a novel cis-allylphosphoryl solid-phase linker that enabled the selective cleavage of the first anomeric-phosphodiester linkage without affecting any of the other internal anomeric-phosphodiester groups of the growing PG chain on the solid support. The strategy to construct larger phosphoglycans in a one-pot synthesis by polycondensation of a single key intermediate is also described, enabling CD spectrometric measurements to show the helical nature of phosphoglycans. Our versatile synthetic approach provides easy access to Leishmania phosphoglycans and the opportunity to address key immunological, biochemical, and biophysical questions pertaining to the phosphoglycan family (LPG and PPG) unique to the parasite.