Achievements and challenges of the Sakigake designation system in Japan.

The Sakigake designation system (Sakigake) has been launched to encourage the pioneered development of innovative new medical products for the effective treatment of severe illness in Japan, which allows leveraging the several advantages in prioritized consultation, rapid review, premium drug pricing and extended data-protection period. We retrospectively analysed the Sakigake products including drugs and regenerative medical products to clarify the achievements and the future issues in this system. From April 2015 to August 2020 (the first 5-year trial period of Sakigake), 37 products were designated, and 10 of those were approved in Japan in which 7 new active substances achieved the first-in-world approvals. Oncology, neurology and cardiovascular disease were the major therapeutic areas, and those 3 accounted for 75.7% of all products. Sakigake achieved some first-in-world approvals by the Pharmaceuticals and Medical Devices Agency/the Ministry of Health, Labor and Welfare of innovative new medical products, although in some therapeutic areas, there remains room in stimulating drug development.

Rationales of delay and difference in regulatory review by Japan, the USA and Europe among new drugs first approved in Japan.

AIMS: To clarify the rationales of delay or difference in the review of new drug applications among regulatory authorities for new drugs, those first approved in the world being in Japan. METHODS: Among 80 new drugs first approved in Japan from 2008 to 2019, we identified those subsequently approved in the USA or Europe. Significant delays in approval time (boxplot outliers) and the rationales for the delays were assessed among the Pharmaceuticals and Medical Devices Agency (PMDA), the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). RESULTS: Of the 80 Japan-first approvals, 25 and 24 were approved in the USA and Europe, respectively, and their median approval times in Japan, the USA and Europe were 285, 334 and 477 days, respectively. Significant delays were identified for pirfenidone (1806 days, FDA), alogliptin benzoate (1856 days, FDA), insulin degludec (1457 days, FDA) and romosozumab (750 days, PMDA; 994 days, FDA; 748 days, EMA). Due to concerns about cardiovascular risk, alogliptin benzoate and insulin degludec were requested for additional clinical trials by the FDA, and romosozumab required a much longer review period than the standard approval time in all three regions. CONCLUSIONS: Among the new drugs significantly delayed in approval time in Japan, the USA or Europe, there were some differences in the requirements, the participating regions and the assessment of clinical trials. The regulatory views on the cardiovascular risk also differed among the three regions. These divergences may be associated with the differences in approval histories.

Evolving Landscape of New Drug Approval in Japan and Lags from International Birth Dates: Retrospective Regulatory Analysis.

The Pharmaceuticals and Medical Devices Agency (PMDA) has approved hundreds of new drugs in recent years. We retrospectively analyzed the new drugs approved in Japan from 2008 to 2019, and identify the first-in-world approvals and clarify the current drug lag. The new drug and the drug lag were defined as a drug with a new active substance and a difference between the approval date in Japan and the international birth date, respectively. Among 400 new drugs approved in Japan during the last 12 years, 80 (20.0%) were first approved in Japan, and 320 were outside Japan (the United States: 202, 50.5%; Europe: 82, 20.5%; other regions: 36, 9.0%). Of these, 45 new drugs have not yet been approved outside Japan, and the remaining 355 have been globally approved in Japan and overseas. The number of new drug approvals were the largest in oncology followed by metabolic/endocrine and infectious diseases. The median drug lags (year) among all 400 new drugs and 355 new drugs with global approvals were 4.3 and 4.7 in the first tertile (2008-2011), 1.5 and 2.6 in the second tertile (2012-2015), and reduced to 1.3 and 2.2 in the third tertile (2016-2019), respectively. Substantial drug lag remains in neurology, psychiatry, and therapeutic areas where the number of new drug approvals was relatively small. Collectively, one-fifth of the new drugs approved in Japan are first-in-world approvals. Drug lag has been greatly decreased, although it still exists.

Current Japanese Regulatory Systems for Generics and Biosimilars.

Currently, biosimilar products are being actively developed around the world. One reason for this is the expiry of patents of original biopharmaceutical products with an extremely large market share because the biosimilar companies need to avoid infringing patents. A representative example of this is biosimilar versions of monoclonal antibodies. In Japan, the Ministry of Health, Labour and Welfare is promoting the use of biosimilar products because the market share of such products is currently extremely low compared with that of generic products. The Pharmaceuticals and Medical Devices Agency is responsible for reviewing generic and biosimilar products in Japan. However, no comparison of review systems for generics and biosimilars in Japan has been published. A more detailed understanding of review systems is important for using generic and biosimilar products. This article presents the current Japanese review systems for generic and biosimilar products and also the future challenges to facilitate the better regulation of both types of product.

Common light signaling pathways controlling DNA repair and circadian clock entrainment in zebrafish.

UV radiation causes a number of harmful events including growth delay, cell death and ultimately cancer. The reversal of such effects by concomitant exposure to visible light is a conserved mechanism which has been uncovered in many multi-cellular organisms. Here we show that light-dependent UV-tolerance is a cell autonomous phenomenon in zebrafish. In addition, we provide several lines of evidence indicating that light induction of 64PHR, a DNA repair enzyme, and the subsequent light-dependent DNA repair mediated by this enzyme are prerequisites for light-mediated UV tolerance. 64PHR is evolutionary related to and has a high degree of structural similarity to animal CRY, an essential circadian regulator. The zebrafish circadian clock is controlled by a cell-autonomous and light-dependent oscillator, where zCRY1a functions as an important mediator of light entrainment of the circadian clock. In this study, we show that light directly activates MAPK signaling cascades in zebrafish cells and we provide evidence that light-induced activation of these pathways controls the expression of two evolutionary-related genes, z64Phr and zCry1a, revealing that light-dependent DNA repair and the entrainment of circadian clock share common regulatory pathways.

CLOCK:BMAL-independent circadian oscillation of zebrafish Cryptochrome1a gene.

In the vertebrate circadian feedback loop, CLOCK:BMAL heterodimers induce the expression of Cry genes. The CRY proteins in turn inhibit CLOCK:BMAL-mediated transcription closing the negative feedback loop. Four CRYs, which all inhibit CLOCK:BMAL-mediated transcription, exist in zebrafish. Although these zebrafish Crys (zCry1a, 1b, 2a, and 2b) show a circadian pattern of expression, previous studies have indicated that the circadian oscillation of zCry1a could be CLOCK:BMAL-independent. Here we show that abrogation of CLOCK:BMAL-dependent transcription in zebrafish cells by the dominant negative zCLOCK3-DeltaC does not affect the circadian oscillation of zCry1a. Moreover, we provide several lines of evidence indicating that the extracellular signal-regulated kinase (ERK) signaling cascade modulates the circadian expression of zCry1a gene in constant darkness. Taken together, our data strongly support the notion that circadian oscillation of zCry1a is CLOCK:BMAL-independent and further indicate that mechanisms involving non-canonical clock genes could contribute to the circadian expression of zCry1a gene in a cell autonomous manner.

Hematopoiesis-dependent expression of CD44 in murine hepatic progenitor cells.

The fetal liver serves as the predominant hematopoietic organ until birth. However, the mechanisms underlying this link between hematopoiesis and hepatogenesis are unclear. Previously, we reported the isolation of a monoclonal antibody (anti-Liv8) that specifically recognizes an antigen (Liv8) present in murine fetal livers at embryonic day 11.5 (E11.5). Liv8 is a cell surface molecule expressed by hematopoietic cells in both fetal liver and adult mouse bone marrow. Here, we report that Liv8 is also transiently expressed by hepatoblasts at E11.5. Using protein purification and mass spectrometry, we have identified Liv8 as the CD44 protein. Interestingly, the expression of Liv8/CD44 in fetal liver was completely lost in AML1(-/-) murine embryos, which lack definitive hematopoiesis. These results show that hepatoblasts change from Liv8/CD44-negative to Liv8/CD44-positive status in a hematopoiesis-dependent manner by E11.5, and indicate that Liv8/CD44 expression is an important link between hematopoiesis and hepatogenesis during fetal liver development.