Document is current

Article History

Received: 11 February 2026

Revised: 14 April 2026

Accepted: 14 April 2026

First Online: 26 April 2026

Declarations

:

: T.H. received honoraria from Sanofi, Gilead Sciences, and Bristol-Myers Squibb. H.T. has received honoraria from Sanofi, Janssen, Gilead Sciences, Chugai, Kyowa Kirin, Nippon Shinyaku, Takeda, and Bristol-Myers Squibb. H.N. has received research grants from MSD, Asahi Kasei Pharma, Astellas, AbbVie, Japan Blood Products Organization, Eisai, Otsuka Pharmaceutical, Ono Pharma, Kyowa Kirin, Sanofi, Shionogi, Daiichi Sankyo, Taiho, Takeda, Mitsubishi Tanabe, Chugai, Teijin Pharma, Eli Lilly, Nippon Kayaku, Nihon Pharmaceutical, Boehringer Ingelheim, Nippon Shinyaku, Taisho Pharmaceutical, and Pfizer. K.M. has received honoraria from Sanofi, Janssen, AstraZeneca, Chugai, Kyowa Kirin, Takeda, Bristol-Myers Squibb, Nippon Shinyaku, SymBio, and Ono Pharmaceuticals. All other authors declare no conflicts of interest.

: This study was conducted as part of an observational study on multiple myeloma and was approved by the Institutional Review Board of Nihon University Itabashi Hospital (approval No. RK-240514–6). The study was conducted in accordance with the most recent version of the Declaration of Helsinki (updated 2008).

: Written informed consent for publication of this case report and any accompanying images was obtained from the patient. Additionally, the patient provided specific written consent for the use of anonymized residual blood samples and exploratory immunophenotyping analyses.

: The patient has consented to the submission and publication of this case report and any anonymized laboratory and/or imaging data.