KTKatsura Tsukamoto

Katsura Tsukamoto

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

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Katsura Tsukamoto has a total of 49 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Benefit-risk assessment of HPV vaccination programs in Australia, the United States, and Japan

    by Miwa Satake, Sae Ito, Chiho Sawano, Paul Scuffham, Katsura Tsukamoto

  • Open Access

    Role of Companion Diagnostics in Advancing Patient-Centered Anticancer Drug Treatment

    by Nanaki Shingyo, Manaka Taguchi, Mizuki Matsubara, Michitaka Shichijo, Naoki Matsumaru, Katsura Tsukamoto

    Cancer is an age-related disease that affects one in two Japanese individuals, placing a significant burden on both patients and caregivers due to its clinical characteristics, high treatment costs, and associated adverse events (AEs). Consequently, cancer treatment remains a major public concern. In recent years, patient-centered medical care has gained increasing attention and is strongly desired in cancer treatment. Companion diagnostics (CDx) are expected to facilitate personalized treatment; however, their current status remains unclear. In this study, we evaluated the role of CDx in anticancer drug treatment based on data available at the time of drug approval. Our analysis revealed that the benefit–risk ratio, defined as the objective response rate of an anticancer drug divided by the incidence of severe AEs, was significantly higher for anticancer drugs requiring CDx (wCDx) in Japanese patients (1.54-fold, p < 0.0135) than for anticancer drugs not requiring CDx. Although the objective response rate did not differ between the 2 groups, the incidence of severe AEs was lower in the wCDx group. These findings suggest that CDx helps identify patients who are better suited for specific anticancer treatments and/or that active pharmaceutical ingredients in wCDx therapies carry a lower risk of severe AEs. To further promote patient-centered medical care, the active development of CDx alongside new anticancer drugs should be encouraged, despite the higher development hurdles, through regulatory support, particularly since drug pricing does not differ between the 2 groups.

  • Approval of high-benefit oncology drugs in Japan: utilization of expedited regulatory pathways for the accelerated approved anticancer drugs

    by Ayumi Taguchi, Naoki Matsumaru, Katsura Tsukamoto

    Summary Early access to promising new drugs with superior efficacy compared to existing treatments is globally sought after. To facilitate such access, regulatory authorities in each country have implemented special regulatory measures that expedite drug approval. This study examined the approval lag of anticancer drugs granted accelerated approval (AA) by the U.S. Food and Drug Administration (FDA) and their corresponding approval timelines in Japan. Additionally, we assessed the use of expedited regulatory pathways in Japan. Our analysis included 55 anticancer drugs that received AA from the FDA between 2012 and 2021 and evaluated their approval in Japan through 2022. The median approval lag was 649 days, primarily attributable to submission delays. Drugs for which Japan participated in the pivotal FDA study and the use of expedited regulatory pathways in Japan had significantly shorter approval lags (P < 0.001 and P = 0.0172, respectively). However, the utilization of the recently implemented conditional early approval system was limited. Although AA anticancer drugs are often approved based on early clinical trial data, our findings highlight that participation in pivotal studies is crucial for minimizing approval delays in Japan. Despite improvements in drug approval timelines, substantial delays persist, underscoring the need for more effective utilization of expedited regulatory pathways. Enhancing collaboration in early-stage clinical trials and optimizing regulatory processes may facilitate faster access to high-benefit anticancer therapies in Japan.


  • Regional Disparity in First-in-Class Anticancer Drug Development in the US, EU, and Japan

    by Yoshitsugu Hino, Miu Okada, Christine Erikstrup Hallgreen, Marie Louise De Bruin, Randell E Doty, Naoki Matsumaru, Katsura Tsukamoto

    A cancer diagnosis is devastating for both patients and their caregivers. With high morbidity and mortality, cancer is a serious disease area with unmet medical needs. Thus, innovative anticancer drugs are in high demand worldwide but are unequally available. Our study focused on first-in-class (FIC) anticancer drugs and investigated their actual development situation in the United States (US), European Union (EU), and Japan over the last two decades to obtain fundamental information for understanding how the aforementioned demands are met, especially to eliminate drug lags among regions. We identified FIC anticancer drugs using pharmacological classes for the Japanese drug pricing system. Most FIC anticancer drugs were first approved in the US. The median approval time for anticancer drugs in new pharmacological classes during the last two decades in Japan (5072 days) was significantly different (p=0.043) from that in the US (4253 days), though it was not significantly different from that in the EU (4655 days). Submission and approval lags between the US and Japan were more than 2.1 years, and those between the EU and Japan were more than 1.2 years. However, those between the US and the EU were less than 0.8 years. The development rate of FIC anticancer drugs in Japan is slower than in other regions. Even among developed countries, FIC anticancer drug lags exist. Considering the high impact of FIC anticancer drugs on society worldwide, we should work together to reduce drug lag among regions using an improved international cooperative framework.


  • Establishment of Mono-scaled Benefit/Risk Analysis of HPV Vaccine

    by Katsura Tsukamoto, Manami Inoue, Hirohito Mori, Naoki Matsumaru

    Decisions concerning approval of human papillomavirus (HPV) vaccines and their use are based on expert evaluation of the vaccines. However, the quantitative differences between vaccine benefits and risks are difficult for non-experts to understand. In this study, we developed a new method to calculate the benefits and risks of the HPV vaccines using disability-adjusted life year (DALY) as the mono-scaled weight for various benefits and risks relevant to the vaccines. We evaluated benefits as a gain of DALY values for cervical cancer and risks as the loss of DALY values for various adverse events by the vaccination. To calculate the loss of DALY values, we integrated all adverse events in the International Classification of Diseases chapters. The novel method reflected the men-women ratio of this epidemiological disease to a certain extent. Among the vaccinated women, 111,372 and 477,190 received a bivalent and quadrivalent vaccine, respectively. The DALY rate of cervical cancer was 148.7. The calculated benefit for the bivalent and quadrivalent vaccines was 149.1 and 638.8, respectively, and set as the theoretical maximum. The risk was calculated as 129.3 and 49.6 in the bivalent and quadrivalent vaccines, respectively. Since HPV vaccines prevent several other cancers, the benefit of the vaccination extends beyond the risk according to this new method.


  • Clinical development of anticancer drugs can be enhanced using efficacy data of small population clinical trials

    by Keiichi Sawachi, Naoki Matsumaru, Katsura Tsukamoto

    Although there are accelerated approval pathways based on data of small populations and surrogate endpoints, the concern that these pathways authorize the use of inefficacious drugs based on limited data from earlier phase clinical trials remains. We retrospectively investigated the efficacy of anticancer drugs, which were approved or whose development was terminated in small and large clinical trials, and verified whether small clinical trials could reflect the results for efficacy in large clinical trials. All anticancer drugs approved in Japan or whose development was terminated from 2015 to 2019 were searched. The median overall survival (OS), median progression-free survival (PFS), and overall response rates (ORR) between small clinical trials (sample size ≤100) and large clinical trials (sample size >100) with identical target populations and treatment settings were compared. Simple linear regression analysis, Spearman's correlation analysis, and paired sample t-test were performed. A total of 61 comparable small and large clinical trials were identified. For all endpoints, statistically significant linear trends and correlation were detected (p < 0.001). There were no statistically significant differences in the median PFS and ORR between small and large clinical trials. The mean differences of both clinical trials were -0.102 months and -1.531%, respectively. Even when the sample size of the clinical trial was increased, the efficacy data of anticancer drugs could not be changed significantly. These results supported the accelerated approval pathway based on the promising efficacy data of small populations in anticancer drug development.


  • Impact of expedited programs in the United States, as foreign regulatory factors, on clinical development time in Japan

    by Gentaro Tajima, Naoki Matsumaru, Katsura Tsukamoto

    Regulatory authorities in several regions have introduced a number of expedited programs (EPs) to promote the development of innovative drugs for patients in their own countries. The EPs in the United States (US), alone or in combination, have been successful in shortening the clinical development time in the US. We examined whether US-EPs, as well as other related factors, have an impact on the clinical development time in Japan to obtain new insights for more efficient drug development. In total, 168 drugs approved as new molecular entities (NMEs) in Japan and approved in the US between 2012 and 2019 were surveyed. We compared the clinical development time in Japan for those drugs with or without US-EPs. We also examined the impact of overlapping designations of US-EPs on clinical development time in Japan. Multiple regression analysis was performed to identify associated factors related to clinical development time in Japan, including US-EPs. The clinical development time in Japan was significantly shorter at 37.4 [Interquartile range, IQR, 28.7-48.9] months for Accelerated Approval (AA), 42.2 [30.0-53.6] months for Breakthrough Therapy (BT), 42.3 [29.3-56.4] months for Fast Track (FT), 44.5 [30.7-60.0] months for US Priority Review, and 45.2 [31.3-61.8] months for US Orphan Designation. Multiple regression analysis revealed that AA (p = 0.008), FT (p = 0.013), Japan Priority Review, and the difference in development initiation dates between the US and Japan were significant factors related to a decrease in the clinical development time in Japan, whereas Japan Orphan Designation and the development of anticancer drugs were significant factors linked to an increase in the clinical development time. US-EPs were associated with a decrease in the clinical development time in Japan for the drugs that were approved as NMEs in Japan and approved in the US. This association was not restricted to particular therapeutic areas or development strategies. Stakeholders involved in drug development, including the drug developers and regulatory authorities in Japan, should realize these effects for efficient drug development.


  • Lag Time for New Innovative, First-in-Class, Drug Approval in Japan

    by Takayuki Miyazaki, Michiyuki Komiyama, Naoki Matsumaru, Hideki Maeda, Katsura Tsukamoto

    Early access to novel drugs, regardless of regional differences, is significant for patients worldwide. Although various efforts have been made to reduce the drug lag, it still exists in some regions, including Japan. In this study, we focused on the drug lag of first-in-class drugs in Japan and obtained fundamental information because we considered that first-in-class and me-too drugs are essentially different and should be treated separately. We analyzed 97 first-in-class and 176 me-too drugs in new molecular entity (NME)-approved drugs in Japan and the United States during the fiscal years between 2009 and 2019. Since government policy and the Evaluation Committee on Unapproved or Off-labeled Drugs with High Medical Needs (the Committee) have a huge impact on drug lag, we distinguished NMEs developed at the Committee’s request. First-in-class drugs were developed at the Committee’s request significantly more than the me-too drugs (p = 0.0034). Although it was not statistically significant, the approval lags were 498.0 d for first-in-class drugs and 535.0 d for me-too drugs. Multiple regression analysis showed that multi-regional clinical trial (MRCT) development strategy (p = 0.0043) and foreign origin drugs (p = 0.0072) were a reducing factor and a prolonging factor of drug lag, respectively. In conclusion, the drug lag for first-in-class drug approval was one year. Global drug development using MRCT is one of the most effective development strategies for reducing drug lags.


  • Open Access

    Characteristics of drugs approved in Japan without conducting confirmatory clinical trials

    by Shunsuke Izuka, Naoki Matsumaru, Katsura Tsukamoto

    What is known and objective Drug development is generally a long and expensive process. Regulatory authorities have established several expedited regulatory pathways, such as accelerated approval designation in the United States (1992) and conditional approval regulation in Japan (2017). In Japan, prior to 2017, the Pharmaceutical and Medical Device Agency (PMDA) granted marketing approval without requesting the results of confirmatory clinical trials case by case basis, and even after 2018, only three drugs have been approved via the conditional approval pathway, although many drugs without confirmatory clinical trials have been approved without this pathway; therefore, it is difficult to predict the circumstances under which confirmatory clinical trials may be waived. The aim of this study was to investigate the characteristics of drugs for which the requirement of confirmatory clinical trials for approval was waived in Japan. We also aimed to identify factors and formulae to predict a waiver of confirmatory clinical trials. Methods Data on approved drugs and their characteristics were mainly extracted from the Japan Pharmaceuticals and Medical Device Agency database. The seriousness of the disease, existence of available treatments and number of patients were considered as candidate factors. The influence of each factor on receiving a waiver was determined using logistic regression analysis comparing drugs approved with and without confirmatory clinical trials as the binary response variable. The predictive formula was derived from the results of the logistic regression analysis. A receiver operating characteristic curve was used to evaluate the accuracy of the prediction. Results and discussion Categorization of drugs as antineoplastic agents, use of the cost accounting method in the drug pricing system, “orphan” designation and accelerated approval designation in the United States emerged as significant factors in the logistic regression analysis, predicting a waiver for confirmatory clinical trials (p ≤ 0.05). These factors were then used to establish a predictive model to ascertain whether confirmatory clinical trials would be necessary for a new drug, exhibiting good sensitivity (0.8) and specificity (0.8) and high accuracy for newly approved drugs. What is new and conclusion The identification of key factors that can predict waivers of confirmatory clinical trials may accelerate the development of clinically important drugs and improve patient access globally.

  • Open Access

    Burden of caring for Alzheimer’s disease or dementia patients in Japan, the US, and EU: results from the National Health and Wellness Survey: a cross-sectional survey

    by Shinya Ohno, Yirong Chen, Hiroyuki Sakamaki, Naoki Matsumaru, Motoaki Yoshino, Katsura Tsukamoto

    The growing prevalence of Alzheimer’s disease (AD) worldwide has sparked the implementation of national policies to support the growing burden among caregivers of AD/dementia patients. This study a...