Opportunities and challenges for use of minipigs in nonclinical pharmaceutical development: Results of a follow-up IQ DruSafe survey

Minipigs are valid nonrodent species infrequently utilized for pharmaceutical research and development (R&D) compared with dogs or nonhuman primates (NHPs). A 2022 IQ DruSafe survey revealed a modest increase in minipig use by pharmaceutical companies compared with a prior 2014 survey, primarily in the development of oral small molecules and parenteral protein molecules. Some companies considered using minipigs more often due to NHP shortages and regional ethical concerns with using NHPs and dogs. However, for most pharmaceutical companies, minipigs still represent ≤5% of their nonrodent animal use. Key challenges noted by companies to wider adoption of minipigs were high test article requirement, limited historical control data, and lack of relevant reagents or assays. Additionally, some companies expressed uncertainties about contract research organization (CRO) capabilities and experience, a perception not shared by respondent CROs. These latest survey results indicate persistence of many concerns previously identified in 2014. Several case studies are included to illustrate areas of expanded minipig use as well as the challenges that hinder broader adoption. Ongoing, focused, and industry-wide initiatives to address the identified or perceived challenges may lead to more frequent or routine consideration of minipigs as a test species in pharmaceutical R&D.

Discovery of the DNA-PKcs inhibitor DA-143 which exhibits enhanced solubility relative to NU7441

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) plays a vital role in DNA damage repair and lymphocyte function, presenting a significant target in cancer and immune diseases. Current DNA-PKcs inhibitors are undergoing Phase I/II trials as adjuncts to radiotherapy and chemotherapy in cancer. Nevertheless, clinical utility is limited by suboptimal bioavailability. This study introduces DNA-PKcs inhibitors designed to enhance bioavailability. We demonstrate that a novel DNA-PKcs inhibitor, DA-143, surpasses NU7441 in aqueous solubility as well as other available inhibitors. In addition, DA-143 displayed an improvement in DNA-PKcs inhibition relative to NU7441 achieving an IC50 of 2.5 nM. Consistent with current inhibitors, inhibition of DNA-PKcs by DA-143 resulted in increased tumor cell sensitivity to DNA-damage from chemotherapy and inhibition of human T cell function. The improved solubility of DA-143 is critical for enhanced efficacy at reduced doses and facilitates more effective evaluation of DNA-PKcs inhibition in both preclinical and clinical development.

Nervous System Sampling for General Toxicity and Neurotoxicity Studies in the Laboratory Minipig With Emphasis on the Göttingen Minipig

The use of minipigs as an alternative nonclinical species has increased in the last 20 years. The Society of Toxicologic Pathology (STP) has produced generic "best practice" recommendations for nervous system sampling in nonrodents during general toxicity studies (Toxicol Pathol 41[7]: 1028-1048, 2013), but their adaptation to the minipig has not been attempted. Here, we describe 2 trimming schemes suitable for evaluating the unique neuroanatomic features of the minipig brain in nonclinical toxicity studies. The first scheme is intended for general toxicity studies (Tier 1) to screen agents with unknown or no anticipated neurotoxic potential; this approach using 7 coronal hemisections accords with the published STP "best practice" recommendations. The second trimming scheme for neurotoxicity studies (Tier 2) uses 14 coronal hemisections and 2 full coronal sections to investigate toxicants where the nervous system is a suspected or known target organ. Collection of spinal cord, ganglia (somatic and autonomic), and nerves from minipigs during nonclinical studies should follow published STP "best practice" recommendations for sampling the central (CNS, Toxicol Pathol 41[7]: 1028-1048, 2013) and peripheral (PNS, Toxicol Pathol 46[4]: 372-402, 2018) nervous systems.

The Neonatal and Juvenile Pig in Pediatric Drug Discovery and Development

Pharmacotherapy in pediatric patients is challenging in view of the maturation of organ systems and processes that affect pharmacokinetics and pharmacodynamics. Especially for the youngest age groups and for pediatric-only indications, neonatal and juvenile animal models can be useful to assess drug safety and to better understand the mechanisms of diseases or conditions. In this respect, the use of neonatal and juvenile pigs in the field of pediatric drug discovery and development is promising, although still limited at this point. This review summarizes the comparative postnatal development of pigs and humans and discusses the advantages of the juvenile pig in view of developmental pharmacology, pediatric diseases, drug discovery and drug safety testing. Furthermore, limitations and unexplored aspects of this large animal model are covered. At this point in time, the potential of the neonatal and juvenile pig as nonclinical safety models for pediatric drug development is underexplored.

Synergistic effects of a cremophor EL drug delivery system and its U0126 cargo in an ex vivo model

Neuroprotection has proven clinically unsuccessful in subarachnoid hemorrhage. We believe that this is because the major component in the early damage pathway, the vascular wall, has not been given the necessary focus. U0126 is a potent inhibitor of vascular phenotypical changes, exemplified by functional endothelin B (ET_B) receptor upregulation. The current study aimed to determine the optimal dose of U0126 ex vivo and test the toxicology of this dose in vivo. To find the optimal dose and test a suitable in vivo delivery system, we applied an ex vivo model of blood flow cessation and investigated functional ET_B receptor upregulation (using a specific agonist) as the primary endpoint. The secondary endpoint was depolarization-induced contractility assessed by 60 mM K⁺ stimuli. Furthermore, an in vivo toxicology study was performed on the optimal selected doses. U0126 (10 µM) had a strong effect on the prevention of functional ET_B receptor contractility, combined with minimal effect on the depolarization-induced contractility. When cremophor EL was chosen for drug delivery, it had an inhibitory and additive effect (combined with U0126) on the ET_B receptor contractility. Hence, 10 µM U0126 in 0.5% cremophor EL seems to be a dose that will be close to the maximal inhibition observed ex vivo on basilar arteries, without exhibiting side effects in the toxicology studies. U0126 and cremophor EL are well tolerated at doses that have effect on ET_B receptor upregulation. Cremophor EL has an additional positive effect, preventing functional ET_B receptor upregulation, making it suitable as a drug delivery system.

Design and Synthesis of a New Soluble Natural β-Carboline Derivative for Preclinical Study by Intravenous Injection

Harmine is a natural β-carboline compound showing several biological activities, including antiproliferative properties, but this soluble natural molecule lacks selectivity. Harmine derivatives were reported to overcome this problem, but they are usually poorly soluble. Here, we designed and synthesized a new 2, 7, 9-trisubstituted molecule (1-methyl-7-(3-methylbutoxy)-9-propyl-2-[(pyridin-2-yl)methyl]-9H-pyrido[3,4-b]indol-2-ium bromide) with a solubility of 1.87 ± 0.07 mg/mL in a simulated injection vehicle. This compound is stable for at least 72 h in acidic and physiological conditions (pH 1.1 and 7.4) as well as in a simulated injection vehicle (physiological liquid + 0.1% Tween80®). Solubility in those media is 1.06 ± 0.08 mg/mL and 1.62 ± 0.13 mg/mL at pH 7.4 and 1. The synthesized molecule displays a significant activity on five different cancer cell lines (IC₅₀ range from 0.2 to 2 µM on A549, MDA-MB-231, PANC-1, T98G and Hs683 cell lines). This compound is also more active on cancer cells (MDA-MB-231) than on normal cells (MCF-10a) at IC₅₀ concentrations. Due to its high activity at low concentration, such solubility values should be sufficient for further in vivo antitumoral activity evaluation via intravenous injection.

Pediatric Formulations: Knowledge Gaps Limiting the Expedited Preclinical to Clinical Translation in Children

Traditionally, drug discovery and development research have been primarily focused on the mitigation of disease treatment for the general adult population, often overlooking the medical needs of pediatric patients. While remarkable progress toward the discovery of better medicines has been made, the pharmacological differences between children and adults are often neglected as part of the translation process. In fact, until recently, children have been considered therapeutic orphans due to the lack of significant drug discovery, formulation development, and dosage form design specifically tailored for pediatric patients. Perhaps the least understood is the significant physiological changes that occur during the maturation process from birth to adulthood. It requires careful considerations to achieve age-specific-desired therapeutic outcomes with minimal toxicity. This introduces considerable risk into the preclinical and clinical testing of new medicaments, which until recently, was avoided based on the conventional approach where a demonstration of safe and efficacious use in adults over several years potentially would minimize the chance of adverse juvenile responses. However, the lack of appropriate drug products for children has led to off-label use of adult medicines with potential life-threatening adverse reactions and health complications. Recent developments and future considerations regarding pediatric drug discovery and development using a patient-centric approach in the context of ontogenic biopharmaceutical considerations are discussed below.

Determination of fatty acid and sphingoid base composition of eleven ceramide subclasses in stratum corneum by UHPLC/scheduled-MRM

INTRODUCTION

Ceramides play a key role in skin barrier function in homeostatic and pathological conditions and can be sampled non-invasively through stratum corneum collection.

OBJECTIVES

To develop a novel UHPLC/Scheduled MRM method for the identification and relative distribution of eleven classes of ceramides, which are separated by UHPLC and determined by their specific retention times. The precise composition of the fatty acid and sphingoid base parts of each individual ceramide is determined via mass fragmentation.

METHODS

More than 1000 human and pig ceramides were identified. Three human and minipig ceramide classes, CER[AS], CER[NS] and CER[EOS] have been investigated in depth.

RESULTS

Sphingoid bases were characterized by a prevalence of chain lengths with sizes from C16 to C22, whereas fatty acids were mainly observed in the range of C22-C26. Overall, the ceramide profiles between human and minipig stratum corneum were similar. Differences in the CER[AS] and CER[NS] classes included a more homogeneous distribution of fatty acids (16-30 carbon atoms) in minipig, whereas in human longer fatty acid chains (> 24 carbon atoms) predominated.

CONCLUSION

The method will be useful for the analysis of healthy and pathological skin in various specie, and the measurement of the relative distribution of ceramides as biomarkers for pharmacodynamic studies.