Qualitative analysis of actual Standard for Exchange of Nonclinical Data (SEND) datasets for Data Domains: Proposition from Japan Pharmaceutical Manufacturers Association SEND Taskforce Team on standardization of nonclinical data.

The Standard for Exchange of Nonclinical Data (SEND) has been adopted by the US FDA, which has required pharmaceutical companies who are developing new drugs for the US market to implement SEND. The Japan Pharmaceutical Manufacturers Association (JPMA) SEND Taskforce Team responded to this situation by starting a project to better understand the contents of SEND datasets. The project focused on domains generally included in the SEND domains for single- and repeat-dose general toxicology studies, and surveyed what kind of information are populated in which domains and in what way. The qualitative analysis of the results indicated that variations exist based on whether or not an individual variable was populated and on how the variable was populated. The Taskforce Team recommends reducing variations not only in the SEND datasets but also in the descriptions in the study protocol and/or final study report. Reduction of such variations should lead to higher quality datasets with powerful and increased searchability so that accumulated SEND datasets should become more valuable. These efforts would provide regulatory agencies with easier review of SEND datasets, which contributes to efficient development of new drug candidates.

Progression process and safety assessment adaptation of endometrial lesions in ENU-induced 2-stage uterine carcinogenicity in a Tg-rasH2 mouse model.

Although acotiamide hydrochloride hydrate (acotiamide-HH) has not been reported to have genotoxic findings in any of the genotoxicity studies or treatment-related toxicological findings in reproductive and developmental studies, suspicious uterine tumorigenesis was observed in the results of a long-term rat carcinogenicity study. To clarify the uterine tumorigenesis of acotiamide-HH, we performed a 2-stage uterine carcinogenicity model in the transgenic rasH2 mouse initiated by N-Ethyl-N-nitrosourea (ENU). This model facilitated the short-term detection of uterine carcinogenic potential, and it appears to be a very useful testing method for assessing the safety of chemicals that may affect uterine tumorigenesis. However, there have not been many reports on this model, and accumulation of case studies using this model is recommended to support its usability. In this study, we performed this carcinogenesis model to not only confirm uterine tumorigenesis of acotiamide-HH but also to confirm the reliability of the model. The results of this study revealed that the endometrial adenocarcinoma found in the long-term rat carcinogenicity study possibly arose spontaneously. Also, we confirmed early induction of a uterine tumor as in previous reports and confirmed that 26 weeks is the appropriate treatment period for this rasH2 mouse model according to time-course observations of uterine tumor development.

Effects of polaprezinc on morphological change of the tongue in zinc-deficient rats.

OBJECTIVE: To examine the effects of polaprezinc on morphologic change of the tongue epithelium and on cell cycle regulation of taste bud cells by using zinc-deficient rats, an animal model of taste disturbance. METHODS: After 28 days of feeding with zinc-sufficient or -deficient diet, the rats fed a zinc-deficient diet were divided into four groups in which 0, 1, 3 and 10 mg/kg of polaprezinc were administered for 28 days with continuation of diet. Histopathological and morphological examinations of the tongue were carried out. RESULTS: Parakeratosis was observed in all rats receiving the zinc-deficient diet and 1 mg/kg polaprezinc but not in rats receiving 3 and 10 mg/kg polaprezinc. The ratio of keratinizing epithelium in the outer and inner circumference were significantly increased from 9.6% and 11.3%, respectively, in zinc-sufficient rats to 36.9% and 32.9%, respectively, in zinc-deficient rats (P<0.001 and <0.01). This increase was reversed to 13.7% and 12.3% in rats that received 3 and 10 mg/kg polaprezinc in the outer circumference, respectively. Same phenomenon was seen in the inner circumference part, 13.0% and 10.8% (P<0.01), respectively. In addition, proliferating cell nuclear antigen-positive cells in the taste bud were significantly decreased from 75.5% in zinc-sufficient rats to 32.2% in zinc-deficient rats (P<0.001). This decrease was reversed to 70.3%, 83.1% and 81.2% in rats that received 1, 3 and 10 mg/kg polaprezinc, respectively. CONCLUSION: Polaprezinc improves parakeratosis and decreases taste bud cell proliferation caused by zinc deficiency. These effects may be involved in mechanisms underlying improvement of taste disorders in animal models.

Verification of a false positive in a two-year rat carcinogenicity study using dual control groups.

There is sometimes controversy over whether or not statistically significant responses produced in carcinogenicity studies have biologically significance. Ambiguous results from our previous two-year oral carcinogenicity study on acotiamide hydrochloride hydrate (acotiamide-HH), a prokinetic drug for functional dyspepsia, in rats made it unclear whether the drug may exhibit uterine carcinogenicity. To check this finding, we performed a second long-term carcinogenicity study using two identical control groups to more accurately evaluate uterine carcinogenesis by considering the incidence of spontaneous neoplasms. Female Fischer 344 rats were divided into three groups: the two control groups (control 1 and 2) were administered vehicle (0.5% w/v methylcellulose) and the acotiamide-HH-treated group was administered 2,000 mg/kg/day of acotiamide-HH by oral gavage for two years. Among all groups, the incidence of endometrial adenocarcinoma (EmA) was highest in the control 2 group, followed by the acotiamide-HH-treated group and the control 1 group. Moreover, acotiamide-HH did not affect the incidence of precursor lesions of EmA. In cases where an ambiguous difference is observed, the use of two control groups allows for a more informed interpretation of the findings in the drug-treated groups. The outcomes in this study strongly support the hypothesis that the increase in EmA in rats treated with acotiamide-HH in our previous study is unrelated to administration of the drug.

Distribution of acotiamide, an orally active acetylcholinesterase inhibitor, into the myenteric plexus of rat and dog stomachs.

AIMS: Acotiamide is the first-in-class drug for the treatment of functional dyspepsia. Although pharmacological and therapeutic actions of acotiamide are thought to be derived from its inhibitory effects on acetylcholinesterase (AChE), whether the concentration of acotiamide at the site of action is sufficient to inhibit AChE remains unclear. Since major site of acotiamide action is thought to be the cholinergic nerve terminals in gastric myenteric plexus, we studied the distribution of [(14)C]acotiamide into gastric myenteric plexus. MAIN METHODS: Distribution of [(14)C]acotiamide was evaluated using macro- and micro-autoradiography in rats and dogs. KEY FINDINGS: The results of macro-autoradiography showed the concentration of radioactivity was 27.9µM in rat stomach, which was 12 times higher than IC50 of acotiamide for rat AChE. Being different from rats, the distribution of radioactivity in the muscular layer was distinguishable from that in the mucosal layer in dog stomach. The concentration of radioactivity in the muscular layer of dog stomach (1.41µM) was approximately two-times lower than those in the mucosal layer, however, it was approximately 1.2 times higher than IC50 of acotiamide for dog AChE. The results of micro-autoradiography also showed the radioactivity distributed homogenously in the muscular layer of rat stomach, suggesting the concentration of radioactivity around the ganglion of myenteric plexus is similar to that in the muscular layer of stomach. SIGNIFICANCE: These findings suggest acotiamide distributes to the myenteric plexus of stomach, a putative site of acotiamide action, with adequate concentrations to inhibit AChE, in both of rat and dog stomachs.