Ofatumumab is the first, fully human, anti-CD20 monoclonal antibody in Phase 3 development for multiple sclerosis (MS). The study focused on changes in lymphocyte subsets in blood and lymphoid tissues and on potential novel biomarkers as a result of anti-CD20 antibody action in Cynomolgus monkeys treated with human equivalent doses of subcutaneous (s.c.) ofatumumab on Days 0, 7, and 14. Axillary lymph nodes (LNs) and blood samples were collected at various time points until Day 90. Lymphocyte subsets were quantified by flow cytometry, while morphological and immune cell changes were assessed by imaging mass cytometry (IMC), immunohistochemistry (IHC), in situ hybridization (ISH), and transcriptome analyses using single-cell methodology. Ofatumumab treatment resulted in a potent and rapid reduction of B cells along with a simultaneous drop in CD20 + T cell counts. At Day 21, IHC revealed B-cell depletion in the perifollicular and interfollicular area of axillary LNs, while only the core of the germinal center was depleted of CD20 + CD21 + cells. By Day 62, the perifollicular and interfollicular areas were abundantly infiltrated by CD21 + B cells and this distribution returned to the baseline cytoarchitecture by Day 90. By IMC CD20 + CD3 + CD8 + cells could be identified at the margin of the follicles, with a similar pattern of distribution at Day 21 and 90. Single-cell transcriptomics analysis showed that ofatumumab induced reversible changes in t-distributed stochastic neighbor embedding (t-SNE) defined B-cell subsets that may serve as biomarkers for drug action. In summary, low dose s.c. ofatumumab potently depletes both B cells and CD20 + T cells but apparently spares marginal zone (MZ) B cells in the spleen and LN. These findings add to our molecular and tissue-architectural understanding of ofatumumab treatment effects on B-cell subsets.

More than 200 medications can induce taste disorders in patients. They not only reduce quality of life for those affected, but can lead to malnutrition, severe dehydration and difficulty in maintaining a therapeutic regimen. Nevertheless, the impact of drug candidates on taste is rarely evaluated in preclinical toxicology studies during the early stage of drug development. Moreover, knowledge about how to investigate these adverse effects is scarce in the toxicology field. Here, we discuss the clinical status of drug-induced taste disorders in patients, with the goal of providing toxicologists with a broad understanding of its prevalence, and how stressful and even dangerous it can be to affected patients. Because taste, smell, and oral trigeminal sensation are highly interdependent, we also address drug-induced changes in olfactory and oral somatosensory perceptions. We then review the biology of the gustatory system (including anatomy and histology), and the latest developments about how taste contributes to flavor perception. Finally, we feature recently optimized preclinical approaches to investigate drug-induced taste change in animal models, including morphological evaluation of taste buds and taste cells, gustatory nerve recording, and behavioral testing. Our goals are to raise awareness of drug-induced taste disorders among toxicologists, share an overview of new approaches and key studies that can be used to identify drug-induced gustatory system toxicity early in the drug development process, and to stimulate further research at this emerging interface of chemosensory disorders with toxicology.

The identification, application, and qualification of safety biomarkers are becoming increasingly critical to successful drug discovery and development as companies are striving to develop drugs for difficult targets and for novel disease indications in a risk-adverse environment. Translational safety biomarkers that are minimally invasive and monitor drug-induced toxicity during human clinical trials are urgently needed to assess whether toxicities observed in preclinical toxicology studies are relevant to humans at therapeutic doses. The interpretation of data during the biomarker qualification phase should include careful consideration of the analytic method used, the biology, pharmacokinetic and pharmacodynamic properties of the biomarker, and the pathophysiology of the process studied. The purpose of this review is to summarize commonly employed technologies in the development of fluidand tissue-based safety biomarkers in drug discovery and development and to highlight areas of ongoing novel assay development.

Abstract. To safeguard patients, regulatory authorities require that new drugs that are to be given by the intravitreal (IVT) route are assessed for their safety in a laboratory species using the same route of administration. Due to the high similarity of ocular morphology and physiology between humans and nonhuman primates (NHPs) and due to the species specificity of many biotherapeutics, the monkey is often the only appropriate model. To this end, intravitreal administration and assessment of ocular toxicity are well established in cynomolgus monkeys (Macaca fascicularis). In contrast, the common marmoset monkey (Callithrix jacchus) is not a standard model for ocular toxicity studies due to its general sensitivity to laboratory investigations and small eye size. It was the purpose of the present work to study whether the marmoset is a useful alternative to the cynomolgus monkey for use in intravitreal toxicological studies. Six marmoset monkeys received repeated (every 2 weeks for a total of four doses) intravitreal injections of 10 or 20 µL of a placebo. The animals were assessed for measurements of intraocular pressure (IOP), standard ophthalmological investigations and electroretinography (ERG). At the end of the dosing period, the animals were sacrificed and the eyes were evaluated histologically. ERG revealed similar results when comparing predose to end-of-study data, and there was no difference between the two dose volumes. A transient increase in the IOP was seen immediately after dosing, which was more pronounced after dosing of 20 µL compared to 10 µL. Ophthalmologic and microscopic observations did not show any significant changes. Therefore, it can be concluded that 10 µL as well as 20 µL intravitreal injections of a placebo are well tolerated in the marmoset. These results demonstrate that the common marmoset is an alternative to the cynomolgus monkey for intravitreal toxicity testing.

Studies in the past have shown that bile ductular hyperplasia correlates with the degree of hepatic fibrosis and that myofibroblasts are a major component of cholangiocellular carcinoma (CCA). However, the mechanism of cross‐talk between bile ductular epithelial cells and hepatic stellate cells during hepatic fibrogenesis and CCA progression was not established. In this study, we identified CRISPLD2, a secretory protein reported to be critical for epithelial morphogenesis during lung and kidney development, as one of the top differentially up‐regulated genes in the liver of a mouse model of nonalcoholic steatohepatitis (NASH). A combined in situ hybridization, histochemistry, immunohistochemistry and image analysis suggested that CRISPLD2 mRNA was expressed in hepatic stellate cells accompanying bile ductules and collagen fibers in the liver of mouse model of NASH and human cirrhotic liver. Furthermore, cancer‐associated myofibroblasts express CRISPLD2 mRNA in human cholangiocarcinoma tissues. These data suggest that CRISPLD2 may play a role in the branching morphogenesis of biliary epithelial cells and participate in hepatic fibrogenesis and cholangiocellular carcinoma progression. Further characterization of the role of CRISPLD2 is important as it may serve a novel candidate for targeted therapy and/or biomarker for hepatic fibrosis and CCA.