Article History
Received: 4 April 2019
Accepted: 14 May 2019
First Online: 25 May 2019
Compliance with ethical standards
:
: Kenji Yamashita is an employee of MSD K.K. (a subsidiary of Merck & Co., Inc., Kenilworth, N.J., USA). Masayuki Kaneko declares that he has no conflict of interest. Mamoru Narukawa declares that he has no conflict of interest.
: This article does not contain any studies with human participants or animals.
: For this study, a formal consent is not required.