Preclinical and translational pharmacology of afucosylated anti-CCR8 antibody for depletion of tumour-infiltrating regulatory T cells.

Background And Purpose: RO7502175 is an afucosylated antibody designed to eliminate C-C motif chemokine receptor 8 (CCR8) Treg cells in the tumour microenvironment through enhanced antibody-dependent cellular cytotoxicity (ADCC).

Experimental Approach: We report findings from preclinical studies characterizing pharmacology, pharmacokinetics (PK)/pharmacodynamics (PD) and safety profile of RO7502175 and discuss the translational PK/PD approach used to inform first-in-human (FiH) dosing strategy and clinical development in solid tumour indications.

Key Results: RO7502175 demonstrated selective ADCC against human CCR8 Treg cells from dissociated tumours in vitro.

HESI workshop summary: Interpretation of developmental and reproductive toxicity endpoints and the impact on data interpretation of adverse events.

The Health and Environmental Sciences Institute Developmental and Reproductive Toxicology (HESI-DART) group held a hybrid in-person and virtual workshop in Washington, DC, in 2022. The workshop was entitled, "Interpretation of DART in Regulatory Contexts and Frameworks." There were 154 participants (37 in person and 117 virtual) across 9 countries.

Isoform-selective TGF-β3 inhibition for systemic sclerosis.

Background: Transforming growth factor β (TGF-β) is implicated as a key mediator of pathological fibrosis, but its pleiotropic activity in a range of homeostatic functions presents challenges to its safe and effective therapeutic targeting. There are three isoforms of TGF-β, TGF-β1, TGF-β2, and TGF-β3, which bind to a common receptor complex composed of TGF-βR1 and TGF-βR2 to induce similar intracellular signals in vitro. We have recently shown that the cellular expression patterns and activation thresholds of TGF-β2 and TGF-β3 are distinct from those of TGF-β1 and that selective short-term TGF-β2 and TGF-β3 inhibition can attenuate fibrosis in vivo without promoting excessive inflammation.

Repeat-dose and embryo-fetal developmental toxicity of zinpentraxin alfa.

Zinpentraxin alfa is a recombinant human pentraxin-2 (PTX-2) developed for the treatment of various fibrotic diseases with the hypothesis that supplementing endogenous PTX-2 levels through intravenous administration should increase its regulatory capacity in circulation and at the site of disease, thereby promoting healing and reducing fibrosis. Zinpentraxin alfa has been studied in various clinical trials, particularly in patients with idiopathic pulmonary fibrosis, where it has demonstrated efficacy in slowing decline in lung function in a phase 2 study. In the present investigation, we summarize findings from 14-day repeat-dose toxicity studies in rats and cynomolgus monkeys supporting early clinical development of zinpentraxin alfa.

Utilizing PK and PD Biomarkers to Guide the First-in-Human Starting Dose Selection of MTBT1466A: A Novel Humanized Monoclonal Anti-TGFβ3 Antibody for the Treatment of Fibrotic Diseases.

MTBT1466A is a high-affinity TGFβ3-specific humanized IgG1 monoclonal antibody with reduced Fc effector function, currently under investigation in clinical trials as a potential anti-fibrotic therapy. Here, we characterized the pharmacokinetics (PK) and pharmacodynamics (PD) of MTBT1466A in mice and monkeys and predicted the PK/PD of MTBT1466A in humans to guide the selection of the first-in-human (FIH) starting dose. MTBT1466A demonstrated a typical IgG1-like biphasic PK profile in monkeys, and the predicted human clearance of 2.

FDA and industry collaboration: Identifying opportunities to further reduce reliance on nonhuman primates for nonclinical safety evaluations.

The nonhuman primate (NHP) has always been a limited resource for pharmaceutical research with ongoing efforts to conserve. This is due to their inherent biological properties, the growth in biotherapeutics and other modalities, and their use in small molecule drug development. The SARS-CoV-2 pandemic has significantly impacted the availability of NHPs due to the immediate need for NHPs to develop COVID-19 vaccines and treatments and the China NHP export ban; thus, accelerating the need to further replace, reduce and refine (3Rs) NHP use.

Neutropenia in Cynomolgus Monkeys With Anti-Drug Antibodies Associated With Administration of Afucosylated Humanized Monoclonal Antibodies.

Removal of the core fucose from the Fc region of humanized monoclonal antibodies (afucosylated antibodies) enhances their antibody-dependent cell cytotoxicity activities in killing cancer cells. Based on the authors' experience and literature, administrations of afucosylated antibodies have been associated with neutropenia in cynomolgus monkeys. However, in a recent general toxicology study conducted with an afucosylated antibody in cynomolgus monkeys, transient neutropenia was observed and correlated with the emergence of anti-drug antibodies (ADAs) in the affected animals.

Nonclinical toxicology development of a novel antibody antibiotic conjugate for treating invasive Staphylococcus Aureus infections.

Invasive Staphylococcus aureus (S. aureus) infections are a leading cause of death and not effectively treated with prolonged standard of care antibiotics. A novel THIOMAB™ antibody antibiotic conjugate (TAC) was developed that uses a bacterial-wall specific antibody to deliver the antibiotic (dmDNA31, a rifamycin analogue) to bacteria to minimize toxicities typically seen with prolonged use of traditional antibiotics.

Surfactant protein D is a biomarker of influenza-related pediatric lung injury.

Background: Biomarkers that can risk-stratify children with influenza virus lower respiratory infection may identify patients for targeted intervention. Early elevation of alveolar-related proteins in the bloodstream in these patients could indicate more severe lung damage portending worse outcomes.

Methods: We used a mouse model of human influenza infection and evaluated relationships between lung pathophysiology and surfactant protein D (SP-D), SP-A, and Club cell protein 16 (CC16).

Current Trends of Practices in Nonclinical Toxicology: An Industry Survey.

The growth in drug development over the past years reflects significant advancements in basic sciences and a greater understanding of molecular pathways of disease. Benchmarking industry practices has been important to enable a critical reflection on the path to evolve pharmaceutical testing, and the outcome of past industry surveys has had some impact on best practices in testing. A survey was provided to members of SPS, ACT, and STP.

Scientific and Regulatory Policy Committee Best Practices: Documentation of Sexual Maturity by Microscopic Evaluation in Nonclinical Safety Studies.

The sexual maturity status of animals in nonclinical safety studies can have a significant impact on the microscopic assessment of the reproductive system, the interpretation of potential test article-related findings, and ultimately the assessment of potential risk to humans. However, the assessment and documentation of sexual maturity for animals in nonclinical safety studies is not conducted in a consistent manner across the pharmaceutical and chemical industries. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology convened an international working group of pathologists and nonclinical safety scientists with expertise in the reproductive system, pathology nomenclature, and Standard for Exchange of Nonclinical Data requirements.

Atypical presentation and pathogenesis of a macaque lymphocryptoviral-associated B-cell lymphoma in a cynomolgus monkey.

We report the unique pathogenesis and presentation of a rapidly progressive B-cell lymphoma in a 3-year-old female cynomolgus monkey on day 50 of a 13-week toxicity study. Clinical pathology evaluation revealed a marked leukocytosis with bicytopenia. A serum protein electrophoresis was consistent with monoclonal gammopathy.

In Vivo Assessment of Antibody-Dependent Enhancement of Influenza B Infection.

A theoretical safety concern proposed in the influenza literature is that therapeutic antiviral antibodies could have the potential for antibody-dependent enhancement (ADE) of infection and disease. ADE may occur when virus-specific antibodies at subtherapeutic, nonneutralizing concentrations facilitate virus uptake and, in some cases, enhance replication, which can lead to an exacerbation of virus-mediated disease. Alternatively, ADE may occur due to antibody-dependent complement activation exacerbating virus-mediated disease in the absence of increased replication.

Physiology of the Neonatal Gastrointestinal System Relevant to the Disposition of Orally Administered Medications.

A thorough knowledge of the newborn (age, birth to 1 month postpartum) infant's gastrointestinal tract (GIT) is critical to the evaluation of the absorption, distribution, metabolism, and excretion (ADME) of orally administered drugs in this population. Developmental changes in the GIT during the newborn period are important for nutrient uptake as well as the disposition of orally administered medications. Some aspects of gastrointestinal function do not mature until driven by increased dietary complexity and nutritional demands later in the postnatal period.

Resolution of unexpected pregnancy-related findings in a rat embryofetal development and toxicokinetic study of monoclonal antibodies specific for hCMV.

Background: Developmental and reproductive toxicity testing is not uniformly warranted for biopharmaceuticals that lack relevant targets in test species. However, RG7667, consisting of two monoclonal antibodies specific for human cytomegalovirus (hCMV), was intended for administration to pregnant women to prevent transmission of CMV to the developing fetus.

Methods: Considering the target indication, a Pilot Embryo Fetal Development/Toxicokinetic study was conducted to assess toxicokinetics in the dam and fetuses and general tolerability.

Applying a weight of evidence approach to the evaluation of developmental toxicity of biopharmaceuticals.

Toxicity studies in pregnant animals are not always necessary for assessing the human risk of developmental toxicity of biopharmaceuticals. The growing experience and information on target biology and molecule-specific pharmacokinetics present a powerful approach to accurately anticipate effects of target engagement by biopharmaceuticals using a weight of evidence approach. The weight of evidence assessment should include all available data including target biology, pharmacokinetics, class effects, genetically modified animals, human mutations, and a thorough literature review.

Use of Severity Grades to Characterize Histopathologic Changes.

The severity grade is an important component of a histopathologic diagnosis in a nonclinical toxicity study that helps distinguish treatment-related effects from background findings and aids in determining adverse dose levels during hazard characterization. Severity grades should be assigned based only on the extent (i.e.

Regulatory Forum Opinion Piece: Review of FDA Draft Guidance Testicular Toxicity-Evaluation during Drug Development Guidance for Industry.

In July 2015, the U.S. Food and Drug Administration (FDA) posted a new draft guidance entitled "Testicular Toxicity: Evaluation during Drug Development Guidance for Industry," with a 90-day public comment period.

Scientific and Regulatory Policy Committee Points to Consider Review: Inclusion of Reproductive and Pathology End Points for Assessment of Reproductive and Developmental Toxicity in Pharmaceutical Drug Development.

Standard components of nonclinical toxicity testing for novel pharmaceuticals include clinical and anatomic pathology, as well as separate evaluation of effects on reproduction and development to inform clinical development and labeling. General study designs in regulatory guidances do not specifically mandate use of pathology or reproductive end points across all study types; thus, inclusion and use of these end points are variable. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology (STP) formed a Working Group to assess the current guidelines and practices on the use of reproductive, anatomic pathology, and clinical pathology end points in general, reproductive, and developmental toxicology studies.

Perspective on a Modified Developmental and Reproductive Toxicity Testing Strategy for Cancer Immunotherapy.

The intent of cancer immunotherapy (CIT) is to generate and enhance T-cell responses against tumors. The tumor microenvironment establishes several inhibitory pathways that lead to suppression of the local immune response, which is permissive for tumor growth. The efficacy of different CITs, alone and in combination, stems from reinvigorating the tumor immune response via several mechanisms, including costimulatory agonists, checkpoint inhibitors, and vaccines.

Combined administration of RG7652, a recombinant human monoclonal antibody against PCSK9, and atorvastatin does not result in reduction of immune function.

RG7652 is a human IgG1 monoclonal antibody designed to inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) binding to hepatic low density lipoprotein receptor (LDL-r), thereby blocking PCSK9-mediated degradation of LDL-r. This therapeutic candidate is under development for the prevention of cardiovascular mortality and morbidity in dyslipidemic patients. The primary objective of this study was to evaluate the potential immunotoxicological effects of RG7652 when given to cynomolgus monkeys either alone or in combination with a daily oral dose of atorvastatin.

Integrated and translational nonclinical in vivo cardiovascular risk assessment: gaps and opportunities.

Cardiovascular (CV) safety concerns are a significant source of drug development attrition in the pharmaceutical industry today. Though current nonclinical testing paradigms have largely prevented catastrophic CV events in Phase I studies, many challenges relating to the inability of current nonclinical safety testing strategies to model patient outcomes persist. Contemporary approaches include a spectrum of evaluations of CV structure and function in a variety of laboratory animal species.

Stems to GEMs: impact of stem cell technology on engineered animal models.

Collectively, these presentations introduced the audience to the roles of ES cells in generating phenotypes of transgenic animals,and they provided examples where the GEMs were used to define molecular mechanisms of disease or where ES cells were used as a therapeutic modality. Points of discussion among audience members reinforced the importance of strain-associated background lesions in animal models, technological advances in imaging functional biology, opportunities for stem cell therapies, and ubiquitination in regulation of cell proliferation. The 2012 American College of Veterinary Pathologists symposium ‘‘Evolutionary Aspects of Animal Models’’ will focus on the proper selection of a relevant animal model in biomedical research as critical to investigative success.

Preclinical safety evaluations supporting pediatric drug development with biopharmaceuticals: strategy, challenges, current practices.

Evaluation of pharmaceutical agents in children is now conducted earlier in the drug development process. An important consideration for this pediatric use is how to assess and support its safety. This article is a collaborative effort of industry toxicologists to review strategies, challenges, and current practice regarding preclinical safety evaluations supporting pediatric drug development with biopharmaceuticals.