In this presentation, as a member of the Harmonization by Doing (HBD) project, I discuss the significance of regulatory science in global medical device development and our experience in the international collaboration process for medical devices. In Japan, most innovative medical therapeutic devices were previously developed and exported by foreign-based companies. Due to this device lag, Japanese had minimal opportunities for receiving treatment with innovative medical devices. To address this issue, the Japanese government has actively accepted foreign clinical trial results and promoted global clinical trials in projects such as HBD. HBD is a project with stakeholders from academia, regulatory authorities, and industry in the US and Japan to promote global clinical trials and reduce device lags. When the project started, medical device clinical trials were not actively conducted in Japan at not just hospitals but also at medical device companies. We started to identify issues under the concept of HBD. After 10 years, we have now become key members in global clinical trials and able to obtain approvals without delay. Recently, HBD has started promoting international convergence. Physicians and regulatory authorities play central roles in compiling guidelines for the clinical evaluation of medical device development, which will be a more active field in the near future. The guidelines compiled will be confirmed with members of academia and regulatory authorities in the United Sates.
Environment that created “medical device lag (MDL)” has changed dramatically, and currently that term is not heard often. This was mainly achieved through the leadership of three groups: government, which determined to overcome MDL and took steps to do so; medical societies, which exhibited accountability in trial participation; and MD companies, which underwent a change in mindset that allowed comprehensive tripartite cooperation to reach the current stage. In particular, the global product development strategy (GPDS) of companies in a changing social environment has taken a new-turn with international harmonization trends, like Global Harmonization Task Force and International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. As a result, this evolution has created opportunities for treatment with cutting-edge MDs in Japanese society. Simultaneously, it has had a major impact on the planning process of GPDS of companies. At the same time, the interest of global companies has shifted to emerging economies for future potential profit since Japan no longer faces MDL issue. This economic trend makes MDLs a greater problem for manufacturers. From the regulatory science viewpoint, this new environment has not made it easy to plan a global strategy that will be adaptable to local societies. Without taking hasty action, flexible thinking from the global point of view is necessary to enable the adjustment of local strategies to fit the situation on the ground so that the innovative Japanese medical technology can be exported to a broad range of societies.
According to the US Food and Drug Administration, pharmacometrics is an emerging science that quantifies drugs, diseases, and trial information to aid efficient drug development and/or regulatory decisions. Quantitative decision making occurs at all stages of drug development. In general, patient-level data are not made available to competitors. However, summary-level data are available. Model-based meta-analysis (MBMA) is a powerful tool for decision making which identifies the candidate position in the market. The limitation of MBMA is the heterogeneity of the treatment effect. In the near future, MBMA application is expected at every stage of drug development.
As diseases know no national boundaries, drug development must be designed at a global level. Drugs are highly regulated to maximize the benefits to public health, which is assessed on a regional basis. The complexity and diversity of stakeholders increase dramatically once multiple international regions are involved. Each stakeholder in drug development depends on customized criteria to make decisions for its own benefit. Thus, a huge gap exists among drug discovery researchers, developers, clinicians, patients, and regulatory bodies. With reasonable scientific evidence gathered and analyzed, mutual agreement can be reached. We believe that this important role of regulatory science and academic involvement will create harmony. By practicing diverse, innovative regulatory scientific research, academia has the potential to become the core of communication among various stakeholder groups. Furthermore, another important responsibility of academia, i.e., knowledge, provides additional aspects to the field of drug development. Those who understand regulatory science can contribute to the efficient achievement of innovative, effective, safe drugs. Thus, research and education are essential roles of academia to allow a better understanding of the balance between benefits and risks. Communication and knowledge will promote the prompt delivery of better medical products to patients in need.
Observational study is necessary for the evaluation of drug effectiveness in clinical practice. In recent years, the use of spontaneous reporting systems (SRS) for adverse drug reactions has increased and they have become an important resource for regulatory science. SRS, being the largest and most well-known databases worldwide, are one of the primary tools used for postmarketing surveillance and pharmacovigilance. To analyze SRS, the US Food and Drug Administration Adverse Event Reporting System (FAERS) and the Japanese Adverse Drug Event Report Database (JADER) are reviewed. Authorized pharmacovigilance algorithms were used for signal detection, including the reporting odds ratio. An SRS is a passive reporting database and is therefore subject to numerous sources of selection bias, including overreporting, underreporting, and a lack of a denominator. Despite the inherent limitations of spontaneous reporting, SRS databases are a rich resource and data mining index that provide powerful means of identifying potential associations between drugs and their adverse effects. Our results, which are based on the evaluation of SRS databases, provide essential knowledge that could improve our understanding of clinical issues.
The review of drugs and medical devices is an integral part of regulatory science. The Pharmaceuticals and Medical Devices Agency (PMDA) evaluates the efficacy, safety, and quality of drugs and medical devices after applications are submitted for regulatory approval. The products are approved when their benefits exceed their risks, i.e., an application is approved if the efficacy of the product in patients was demonstrated and the safety of the product is acceptable in view of its observed benefits. However, drugs and medical devices for which efficacy was not clearly demonstrated in clinical trials makes the decision to approve a difficult process. Under those circumstances, the approval process is based on the totality of information, such as the reason why clinical trials did not succeed and medical needs in Japan. The Wingspan stent system, which was approved for the treatment of intracranial arterial stenosis, is an example of a product with a use different from that intended by the US Food and Drug Administration and PMDA.
Clinical identity of nonalcoholic steatohepatitis (NASH) has established it as a chronic liver disease since the 1990s in the USA and in the 21st century in Japan, although its significance is not well recognized in Japanese society. It is characterized as a chronic liver disease, differentiated from viral liver disease and alcoholic liver disease. Nonalcoholic fatty liver disease (NAFLD) comprises nonalcoholic fatty liver (NAFL) and NASH. NASH is considered to be the hepatic manifestation of a metabolic syndrome. It is understood that among individuals with NAFLD, NAFL is a benign condition, whereas NASH can progress to cirrhosis and ultimately to hepatocellular carcinoma. The precise mechanism of NASH is poorly understood, although insulin resistance, oxidative stress and multiple parallel hits theory have been reported. Computed tomography and ultrasonography are performed to detect NAFLD, but these are not sufficient to distinguish between NAFL and NASH. The distinct diagnosis of NAFL and NASH is currently made by liver biopsy, requiring hospitalization. Therefore, there is an urgent need to develop simple, non-invasive markers that can accurately distinguish between NASH and NAFL. In Japan, the number of NASH patients is estimated to be about 1 million. The treatment of NASH comprises changes in life style, including eating habits and exercise that will lead to weight loss, and drug intake, including vitamin E. Based on the global increase in obese people, NASH as a chronic liver disease will become the most important chronic liver disease in the 21st century, not only in Japan but also worldwide.
Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) have been recognized as metabolic disorders characterized by fatty accumulation in the liver without alcohol consumption. The diseases can cause metabolic syndromes, consisting of obesity, diabetes mellitus (DM), dyslipidemia and hypertension. For the treatment of NAFLD/NASH, losing weight by exercise or diet remains the standard treatment, because no effective pharmacological therapy has yet been developed for NAFLD/NASH. Two incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), stimulate glucose-mediated insulin production in pancreatic β cells. Incretin has also been reported to have various extra-pancreatic effects, including the regulation of hepatic glucose production, appetite and satiety, as well as the stimulation of afferent sensory nerves. Therefore, incretin may have potential as a novel therapeutic agent for NAFLD/NASH.
Nonalcoholic steatohepatitis (NASH) is a chronic progressive liver disease characterized by intense liver steatosis accompanied by hepatocyte destruction, inflammation and fibrous, despite little or no history of alcoholic consumption. There are also cases of drug-induced secondary steatohepatitis. Drug-induced steatohepatitis is a relatively rare type of drug-induced liver disease, but close attention to the possible onset of steatohepatitis is needed when drugs with the potential to induce fatty liver are prescribed for long term use. Estrogen is a factor indispensable to smooth fatty acid β-oxidation in hepatocytes. However, treatment with Tamoxifen markedly suppresses fatty acid β-oxidation in the liver. As free fatty acids are toxic, their accumulation results in the activation of alternative fatty acid oxidation pathways mediated by CYP2E1 in cytosol and lipid peroxidases in peroxisomes in hepatocytes. CYP2E1 enhances lipid peroxidation and dicarboxylic acid synthesis via the activation of fatty acid ω-oxidation that injures mitochondria and results in the emergence of ballooned hepatocytes. In such cases, the attenuation of alternative fatty acid oxidation pathways could have some beneficial effects on mitochondrial injury, since fibrates (PPAR-α ligands) are potent enough to stimulate neutral fat consumption through the activation of peroxisomal fatty acid β-oxidation. Fortunately, fibrates attenuate serum estrogen levels by affecting estrogen receptor expression, so the co-administration of fibrates with Tamoxifen is expected to exert higher efficacy in breast cancer patients with Tamoxifen-induced hepatic steatosis.
Nonalcoholic fatty liver disease (NAFLD) is characterized by the pathological accumulation of fat in the liver in the absence of any other disease related to liver steatosis, which includes a wide spectrum of liver diseases ranging from mild asymptomatic fatty liver to nonalcoholic steatohepatitis (NASH) and cirrhosis. Recently, it was reported that NAFLD is characterized by the impaired bioavailability of liver n-6 and n-3 long-chain polyunsaturated fatty acids (PUFAs). That is, compared with healthy individuals, steatosis and steatohepatitis patients have higher n-6/n-3 PUFA ratios. Furthermore, per recent research, decreasing the intake of total fats and increasing the intake of n-3 PUFAs may be beneficial in the treatment of NAFLD. In contrast, some reports describe that NASH patients have more metabolic abnormalities than NAFLD patients; however, these are not influenced by dietary fatty acids. Thus, at present, various opinions exist regarding the efficacy of n-3 PUFA in the treatment of NAFLD. In this review, we discuss the considerable interest n-3 PUFA has attracted as a potential treatment for NAFLD.
The characteristics and functional roles of opioids originally present in vivo (endogenous opioids) in guinea-pig ileum were investigated. The release of endogenous opioids was determined by the inhibitory twitch response evoked by 0.1 Hz stimulation after 10 Hz stimulation (post-tetanic twitch inhibition). The effects of peptidase inhibitors increased the post-tetanic twitch inhibition, prevented by β-funaltrexamine and nor-binaltorphimine, which are selective μ- and κ-opioid receptor subtype antagonists, respectively. Dopamine receptor antagonists (haloperidol, sultopride and domperidone) increased the post-tetanic twitch inhibition. These results suggest that dopamine receptors are involved in modulation of the ileal opioid system, so as to diminish endogenous opioid release by tetanic stimulation, and dopamine antagonists increase the opioid action, that might depend more on the increased release of endogenous opioids. The post-tetanic twitch inhibition was inhibited by adrenalectomy, and showed the supersensitivity of the opioid receptors, resulting from a decrease of endogenous opioids by adrenalectomy. These findings suggest that the increase in morphine-analgesia by adrenalectomy was due to this process. In the presence of naloxone, an opioid antagonist, an increase in basal tension after tetanic stimulation (10 Hz stimulation) (post-tetanic contraction) was observed, and was blocked by spantide, a substance P antagonist, and indomethacin, a prostaglandins-biosynthesis inhibitor. This contraction increased with morphine or peptidase inhibitor exposure, depending on the length of time the ileum was exposed to the morphine or peptidase inhibitor. Post-tetanic contraction might be a useful indicator of the formation of physical dependence to morphine or endogenous opioids in the ileum.
Since 1979, synthetic studies of bioactive heterocyclic natural products and condensed heteroaromatic compounds based on the thermal electrocyclic reaction of 6π-electron or aza-6π-electron systems incorporating the double bond of the principal aromatic or heteroaromatic ring have been conducted by our research group. In this review, five types of electrocyclic and azaelectrocyclic reaction are described: 1) the synthesis of the carbazole alkaloids hyellazole and 6-chlorohyellazole through the electrocyclic reaction of 2,3-bisalkenylindoles; 2) synthetic studies of the pyridocarbazole alkaloids ellipticine and olivacine through the electrocyclic reactions of the indole-2,3- and pyridine-3,4-quinodimethane intermediates; 3) synthetic studies of polysubstituted carbazole alkaloids through the allene-mediated electrocyclic reactions involving the indole 2,3-bond; 4) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 1-aza-6π-electron system using the oxime or oxime ether; and 5) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 2-aza-6π-electron system using a carbodiimide or isocyanate.
Obesity is a major risk factor for diabetes, hypertension, hyperlipidemia, and arteriosclerosis. Although the middle and late stages of adipocyte differentiation are well characterized, the earliest step in the differentiation process has remained largely unknown. We isolated 102 genes expressed at the beginning of the differentiation of a mouse preadipocyte cell line, 3T3-L1 cells. Because approximately half of these genes were unknown, we named them factor for adipocyte differentiation (fad) genes. I first show how these genes regulate the early stage of adipocyte differentiation. We next generated fad104-deficient mice, and demonstrated that fad104-deficient mice died due to cyanosis-associated lung dysplasia with atelectasis. We also found that fad104 positively regulated adipocyte differentiation and negatively regulated osteoblast differentiation. We then demonstrated that fad24-knockdown inhibited mitotic clonal expansion (MCE) and that FAD24 contributed to the regulation of DNA replication by recruiting histone acetyltransferase binding to ORC1 (HBO1) to DNA replication origins. In vitro culture experiments revealed that fad24-null embryos developed normally to the morula stage, but acquired growth defects in subsequent stages. These results strongly suggest that fad24 is essential for pre-implantation in embryonic development, particularly for progression to the blastocyst stage. These findings together indicate that both fad104 and fad24 contribute not only to adipogenesis but also to other physiological events. The multi-functional roles of these genes are discussed.
Molecular imaging is a newly emerging field aimed at advancing our understanding of biology and medicine through the noninvasive in vivo investigation of cellular molecular events involved in normal and pathologic processes. In this field, researchers and/or clinicians are combining modern tools of molecular and cell biology with state of the art technology in order to noninvasively image living subjects. Various imaging modalities such as optics (fluorescence and luminescence), nuclear magnetic resonance imaging, ultrasound, and radiation are being used to visually capture and study molecular and cellular events in living organisms. Among these modalities, nuclear medical molecular imaging uses radionuclides [i.e., positron emission tomography (PET) and single-photon emission computed tomography (SPECT)], and has characteristic properties that allow researchers and/or clinicians to obtain functional images of living subjects with high sensitivity. Translational molecular imaging, a research step between animal experiments and the clinical setting, has been successful when using nuclear medical molecular imaging. This approach leads to better methods for studying biological processes, as well as for diagnosing and managing diseases. In this review, two topics associated with our research on nuclear medical molecular imaging are summarized: (1) the development of a nuclear medical molecular imaging probe that targets cerebral nicotinic acetylcholine receptors (nAChRs), and the translational molecular imaging research conducted using this nAChR imaging probe; and (2) the development of oxygen-dependent degradable nuclear medical molecular imaging probes that target hypoxia-inducible factor-1-active tumor microenvironments.
With the development of cell biology and microbiology, it has become easy to culture many types of animal cells and microbes, and they are frequently used for phenotypic screening to explore medicinal seeds. On the other hand, it is recognized that cells and pathogenic microbes present in pathologic sites and infected regions of the human body display unique properties different from those under general culture conditions. We isolated several bioactive compounds from marine medicinal resources using constructed bioassay-guided separation focusing on the unique changes in the characteristics of cells and pathogenic microbes (Mycobacterium spp.) in the human body under disease conditions. In addition, we also carried out identification studies of target molecules of the bioactive compounds by methods utilizing the gene expression profile, transformants of cells or microbes, synthetic probe molecules of the isolated compounds, etc., since bioactive compounds isolated from the phenotypic screening system often target new molecules. This review presents our phenotypic screening systems, isolation of bioactive compounds from marine medicinal resources, and target identification of bioactive compounds.
The introduction of generic drugs is promoted from the perspective of medical economics. In this context, we need to understand not only the bioequivalence of generic drugs specified in “the Guidelines for Bioequivalence Studies of Generic Products”, but also formulation properties to consider their effect on pharmacological therapy. We evaluated the pharmaceutical characteristics of rebamipide formulations, a brand-name drug and two generic drugs, and their clinical functionality by using rat models of gastric mucosal injury induced by non-steroidal anti-inflammatory drugs (NSAIDs). Pharmaceutical evaluation showed significant differences in hardness. The inter-lot variation was small in all rebamipide formulations. In the clinical functionality study, biochemistry test values 7 d after the administration of rebamipide showed no differences among formulations. Higher levels of mucosal fluid secretion and antioxidative enzymes were observed in the groups administered rebamipide than in the control group. The levels of lipid peroxide were lower in the groups administered rebamipide than the control group. Multivariate analysis showed slight divergence between the brand-name and generic drugs. In future, it will be necessary to select generic drugs after careful consideration of bioequivalence, clinical functionality, and therapeutic equivalence by reviewing scientific evidence such as indication and formulation design, not to mention stable provision.