Overview of 3Rs opportunities in drug discovery and development using non-human primates

Ocular Safety and Toxicokinetics of Bevacizumab-bvzr (Zirabev), a Bevacizumab Biosimilar, Administered to Cynomolgus Monkeys by Intravitreal Injection

Purpose: Bevacizumab-bvzr (Zirabev®), a recombinant humanized monoclonal antibody targeting vascular endothelial growth factor and a biosimilar to bevacizumab, is approved for intravenous administration for various indications worldwide. The objectives of this study were to evaluate the ocular toxicity, systemic tolerability, and toxicokinetics (TKs) of bevacizumab-bvzr following repeat intravitreal (IVT) injection to cynomolgus monkeys. Methods: Male monkeys were administered saline, vehicle, or bevacizumab-bvzr at 1.25 mg/eye/dose once every 2 weeks (3 doses total) for 1 month by bilateral IVT injection, followed by a 4-week recovery phase to evaluate the reversibility of any findings. Local and systemic safety was assessed. Ocular safety assessments included in-life ophthalmic examinations, tonometry (intraocular pressure, IOP), electroretinograms (ERGs), and histopathology. In addition, concentrations of bevacizumab-bvzr were measured in serum and in ocular tissues (vitreous humor, retina, and choroid/retinal pigment epithelium) and ocular concentration-time profiles and serum TKs were evaluated. Results: Bevacizumab-bvzr was tolerated locally and systemically, with an ocular safety profile comparable to the saline or vehicle control group. Bevacizumab-bvzr was observed in both serum and in the evaluated ocular tissues. There were no bevacizumab-bvzr-related microscopic changes or effects on IOP or ERGs. Bevacizumab-bvzr-related trace pigment or cells in vitreous humor (in 4 of 12 animals; commonly associated with IVT injection) and transient, nonadverse, mild ocular inflammation (in 1 of 12 animals) were noted upon ophthalmic examination and fully reversed during the recovery phase. Conclusions: Bevacizumab-bvzr was well tolerated via biweekly IVT administration in healthy monkeys, with an ocular safety profile comparable to saline or its vehicle control.

Society of Toxicologic Pathology Neuropathology Interest Group Article: Neuropathologic Findings in Nonhuman Primates Associated With Administration of Biomolecule-Based Test Articles

The increasing specificity of novel druggable targets coupled with the complexity of emerging therapeutic modalities for treating human diseases has created a growing need for nonhuman primates (NHPs) as models for translational drug discovery and nonclinical safety assessment. In particular, NHPs are critical for investigating potential unexpected/undesired on-target and off-target liabilities associated with administration of candidate biotherapeutics (nucleic acids, proteins, viral gene therapy vectors, etc.) to treat nervous system disorders. Nervous system findings unique to or overrepresented in NHPs administered biomolecule-based ("biologic") test articles include mononuclear cell infiltration in most neural tissues for all biomolecule classes as well as neuronal necrosis with glial cell proliferation in sensory ganglia for certain viral vectors. Such test article-related findings in NHPs often must be differentiated from procedural effects (e.g., local parenchymal or meningeal reactions associated with an injection site or implanted catheter to administer a test article directly into the central nervous system) or spontaneous background findings (e.g., neuronal autophagy in sensory ganglia).

Selected Resources for Pathology Evaluation of Nonhuman Primates in Nonclinical Safety Assessment

Humans and nonhuman primates (NHPs) share numerous anatomical and physiological characteristics, thereby explaining the importance of NHPs as essential animal models for translational medicine and nonclinical toxicity testing. Researchers, toxicologic pathologists, toxicologists, and regulatory reviewers must be familiar with normal and abnormal NHP biological traits when designing, performing, and interpreting data sets from NHP studies. The current compilation presents a list of essential books, journal articles, and websites that provide context to safety assessment and research scientists working with NHP models. The resources used most frequently by the authors have been briefly annotated to permit readers to rapidly ascertain their applicability to particular research endeavors. The references are aimed primarily for toxicologic pathologists working with cynomolgus and rhesus macaques and common marmosets in efficacy and safety assessment studies.

Monetary Value of Live Trade in a Commonly Traded Primate, the Long-Tailed Macaque, Based on Global Trade Statistics

Non-human primates (primates) are regarded as key research subjects for pre-clinical trials of several drugs aimed to alleviate human suffering. It has long been suggested that the predominant species in the international trade in live primates for use in research is the long-tailed macaque (Macaca fascicularis). However, little is still known about the value of this international trade. Whilst the international trade to supply the requirement for biomedical testing is known to encourage illegal wildlife trade, we lack a detailed understanding of the overall value and magnitude of this trade. Such information is vital to facilitate the design of effective conservation strategies in range countries, in order to mitigate the exploitation of wild populations by organized crime networks. Here, data from CITES and the UN Comtrade databases were combined to calculate the value of this trade. We also compared the number of individual primates traded as reported in the two databases to investigate possible correlations. Results show that, from 2010 to 2019, the international trade in long-tailed macaques constituted a market worth of ~US $1.25 billion. We found a positive correlation between individual primates traded in the UN Comtrade Database and individual long-tailed macaques reported in the CITES Trade Database, suggesting that we can use the UN Comtrade database to investigate values and magnitude of the international legal trade in wildlife, and that legal trade in live primates is primarily constituted of long-tailed macaques alone.

OUP accepted manuscript

Pyroglutamate amyloid beta3–42 (pGlu-Abeta3–42), a highly amyloidogenic and neurotoxic form of Abeta, is N-terminally truncated to form a pyroglutamate and has recently been proposed as a key target for immunotherapy. Optimized ACI-24, a vaccine in development for the treatment and prevention of Alzheimer’s disease, focuses the antibody response on the first 15 N-terminal amino acids of Abeta (Abeta1–15). Importantly, clinical data with an initial version of ACI-24 incorporating Abeta1–15, established the vaccine’s safety and tolerability with evidence of immunogenicity. To explore optimized ACI-24’s capacity to generate antibodies to pGlu-Abeta3–42, pre-clinical studies were carried out. Vaccinating mice and non-human primates demonstrated that optimized ACI-24 was well-tolerated and induced an antibody response against Abeta1–42 as expected, as well as high titres of IgG reactive with pyroGlu-Abeta. Epitope mapping of the polyclonal response confirmed these findings revealing broad coverage of epitopes particularly for Abeta peptides mimicking where cleavage occurs to form pGlu-Abeta3–42. These data are in striking contrast to results obtained with other clinically tested Abeta targeting vaccines which generated restricted and limited antibody diversity. Taken together, our findings demonstrate that optimized ACI-24 vaccination represents a breakthrough to provide a safe immune response with a broader Abeta sequence recognition compared to previously tested vaccines, creating binders to pathogenic forms of Abeta important in pathogenesis including pGlu-Abeta3–42.

Antihyperlipidemic potential of diosmin in Swiss Albino mice with high-fat diet induced hyperlipidemia

The aim of this study was to investigate the antihyperlipidemic potential of Diosmin (DS) in mice fed with a high-fat diet (HFD). Animals were divided in five groups (n = 6). The total duration of the study was 90 days split into two intervals. During the first 45-day interval, mice were administered with HFD, whereas during the second 45-day interval they were co-administered HFD plus DS or the standard drug atorvastatin. DS was administered at the dose of 100 and 200 mg/kg;p.o. DS treatment to HFD-induced hyperlipidemic mice caused significant decrements in the levels of total cholesterol, triglycerides, LDL-C and VLDL-C. Moreover, DS resulted in significant increase in the levels of HDL-C and improvements in total protein levels, whereas it caused remarkable decreases in SGOT, SGPT and ALP enzymatic activities in hyperlipidemic mice. Histopathological examination of hyperlipidemic mice revealed a disorganized hepatic tissue, fatty changes, and mononuclear cell infiltration, which were all ameliorated by DS administration. The results revealed that DS possesses potential ameliorating benefits again.st hyperlipidemia induced by HFD on lipid profile, liver function enzymes and hepatic histoarchitecture. Further investigations are highly recommended and clinical trials are warranted in order to assess the efficacy and to fully dissect the mode-of-action underpinning the observed antihyperlipidemic effect of DS.

Porcine cancer models: potential tools to enhance cancer drug trials

INTRODUCTION

The amount of time and money invested into cancer drug research, development, and clinical trials has continually increased over the past few decades. Despite record high cancer drug approval rates, cancer remains a leading cause of death. This suggests the need for more effective tools to help bring novel therapies to clinical practice in a timely manner.

AREAS COVERED

In this review, current issues associated with clinical trials are discussed, specifically focusing on poor accrual rates and time for trial completion. In addition, details regarding preclinical studies required before advancing to clinical trials are discussed, including advantages and limitations of current preclinical animal cancer models and their relevance to human cancer trials. Finally, new translational porcine cancer models (Oncopig Cancer Model (OCM)) are presented as potential co-clinical trial models.

EXPERT OPINION

In order to address issues impacting the poor success rate of oncology clinical trials, we propose the incorporation of the transformative OCM 'co-clinical trial' pathway into the cancer drug approval process. Due to the Oncopig's high homology to humans and similar tumor phenotypes, their utilization can provide improved preclinical prediction of both drug safety and efficacy prior to investing significant time and money in human clinical trials.