Funding

This study was funded by Taiho Pharmaceutical Co., Ltd. The funding body (Taiho Pharmaceutical Co., Ltd.) participated in the study design, data collection, data management, and data analysis under the guidance of the principal investigator. The corresponding author had full access to all the data in the study and took the final responsibility of making the decision to submit the manuscript for publication.

Conflicts of interest/competing interests

All authors report support for the present manuscript (e.g., funding, provision of study materials, medical writing, and article processing charges) from Taiho Pharmaceutical Co., Ltd K.K. Mitsuru Yokota, Hitoshi Ojima, Naotoshi Sugimoto, Yasushi Tsuji, and Soichiro Ishihara have no other conflicts of interest. Yu Sunakawa has received institutional grants or contracts from Chugai, Taiho, Takeda, Otsuka, and Eli Lilly Japan; payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Eli Lilly Japan, Bristol Myers Squibb, Chugai, Takeda, Ono, Merck Biopharma, Taiho, Bayer, Daiichi Sankyo, MSD, Sysmex, and Guardant Health; and has participated on the data safety monitoring board or advisory board of Merck Biopharma, Ono, and Guardant Health. Yasutoshi Kuboki has received institutional grants or contracts from Taiho, Takeda, Ono, AbbVie, Janssen Oncology, Boehringer Ingelheim, Incyte, Amgen, Chugai, GlaxoSmithKline, Genmab, Astellas, Daiichi Sankyo, and Eli Lilly Japan; personal consulting fees from Amgen, Takeda, and Boehringer Ingelheim; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Taiho, Ono, Bayer, Eli Lilly Japan, Bristol Myers Squibb, and Merck Serono. Jun Watanabe has received institutional grants or contracts from Medtronic, Amco, and Terumo; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Medtronic, Johnson & Johnson, Eli Lilly Japan, and Takeda. Tetsuji Terazawa has received consulting fees from Chugai, Eli Lilly Japan, Taiho, and Sanofi; has been part of the data safety monitoring board or advisory board of Sanofi; and is an employee of Shionogi. Hisato Kawakami has received institutional grants or contracts from Eisai, Kobayashi, and Bristol Myers Squibb; personal consulting fees from Daiichi Sankyo; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Bristol Myers Squibb, Eli Lilly Japan, Ono, Daiichi Sankyo, Takeda, Teijin, Otsuka, Bayer, MSD, Chugai, Merck Biopharma, Yakult, and Taiho. Masato Nakamura has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Eli Lilly Japan, Nihon Servier, Daiichi Sankyo, Ono, Taiho, Yakult, Merck & Co., Bayer, Chugai, Merck Biopharma, Otsuka, Takeda, and AstraZeneca. Masahito Kotaka has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Chugai, Takeda, Taiho, Yakult, and Eli Lilly Japan. Eiji Oki has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Taiho, Takeda, Chugai, Bristol Myers Squibb, Bayer, Eli Lilly Japan, and Ono. Takeshi Kajiwara has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Chugail, Eli Lilly Japan, Bristol Myers Squibb, Taiho, and Ono. Yoshiyuki Yamamoto has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Ono, Bristol Myers Squibb, Yakult, Chugai, Eli Lilly Japan, Bayer, Taiho, Servier, Takeda, Daiichi Sankyo, AstraZeneca, and Insight. Tadamichi Denda has received institutional grants or contracts from Ono, MSD, Bristol Myers Squibb Foundation, Amgen, and Pfizer; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Daiichi Sankyo, Sysmex, and Ono. Takao Tamura has received institutional grants or contracts from Chugai, Ltd; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Takeda, Eli Lilly Japan K.K., Bristol Myers Squibb, Ono, and Chugai. Hiroya Taniguchi has received institutional grants or contracts from Takeda, Daiichi Sankyo, and Ono; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Takeda, Ono, Eli Lilly Japan, Merck Biopharma, and Chugai. Takako Eguchi Nakajima has received institutional grants or contracts from Guardant Health, Taiho, Takeda, Chugai, Nippon Kayaku Co., AbbVie, Eli Lilly Japan, Shionogi, Otsuka, and Taisho; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Sumitomo Dainippon, Boehringer Ingelheim, Bristol Myers Squibb, Ono, Taiho, Amgen, Takeda, Chugai, Sanofi, Novartis Japan, Daiichi Sankyo, AstraZeneca, IQVIA, GlaxoSmithKline, NOBEL Pharma, and Parexel. Satoshi Morita has received payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Bristol Myers Squibb, Chugai, Taiho, Eli Lilly Japan, and AstraZeneca. Kuniaki Shirao has received institutional grants or contracts from Ono. Naruhito Takenaka and Daisuke Ozawa are employees of Taiho. Takayuki Yoshino has received institutional grants or contracts from Amgen K.K., Chugai, Daiichi Sankyo, Eisai, Falco Biosystems Ltd, Genomedia Inc., Molecular Health GmbH, MSD, Nippon Boehringer Ingelheim, Ono, Pfizer Japan Inc., Roche Diagnostics K.K., Sanofi, Sysmex, and Taiho; personal consulting fees from Sumitomo Corporation; and payment or honoraria for lectures, presentations, speaker’s bureau, manuscript writing, or educational events from Bayer, Chugai, Merck Biopharma, MSD, Ono, and Takeda.

Ethics approval

The study protocol was approved by the National Cancer Center Hospital East Certified Review Board (CRB3180009) and conducted according to the Declaration of Helsinki and Clinical Trials Act. This study is registered with the Japan Registry of Clinical Trials (jRCTs031180122).

Consent to participate

Informed consent was obtained from all individual participants included in this study.

Consent to publish

Not applicable.

Availability of data and material

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Code availability

Not applicable.

Author contributions

YS, YK, TTe, EO, SI, HT, TEN, and TY comprised the steering committee, which coordinated trial implementation at all sites, including coordination of the study protocol and resolution of doubts in its interpretation. YS, YK, JW, TTe, HK, MY, MN, MK, NS, HO, EO, TK, YY, YT, TD, TTa, SI, HT, TEN, and TY collected data. All authors interpreted the data, and SM analyzed the data. YS was responsible for the decision to submit the manuscript.