CASE REPORT article
Front. Oncol.
Sec. Hematologic Malignancies
This article is part of the Research TopicChimeric Antigen Receptor T Cell Therapies and Bispecific Antibodies in Hematologic MalignanciesView all 6 articles
Case Report: Autologous Stem Cell Boost Enables Hematopoietic Recovery After Severe Cytopenia Induced by BCMA-Targeted Bispecific Antibody Therapy in Multiple Myeloma
Provisionally accepted
Hiroaki Akiyama1
Seiji Kakiuchi1*
Akimasa Sakamoto1Naru Tomigaki1Shutaro Fujioka1Isamu Harima1Ryotaro Niwa1
Ikumi Takagi1Yoko Kozuki1Yoshiharu Miyata1Kyoko Yoshihara2
Satoshi Yoshihara2Nobuko Iwata1- 1Yodogawa Christian Hospital, Osaka, Japan
- 2Hyogo Ika Daigaku, Nishinomiya, Japan
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Elranatamab, a bispecific antibody targeting B-cell maturation antigen (BCMA) and CD3, has shown significant efficacy in relapsed or refractory multiple myeloma (RRMM). However, elranatamab therapy also carries a risk of hematologic toxicity. Stem cell boost (SCB), involving reinfusion of previously collected autologous CD34+ hematopoietic stem cells, has been explored as a salvage strategy after Chimeric Antigen Receptor T-cell (CAR T-cell) therapy-related cytopenias. To date, its role following bispecific antibody treatment remains unclear. We report the case of a 59-year-old man with RRMM who developed prolonged pancytopenia after elranatamab therapy, successfully rescued with autologous SCB. Neutrophil recovery occurred by day +10, transfusion independence by day +19, and hematologic recovery allowed elranatamab resumption without recurrence of severe cytopenia. This case demonstrates the potential utility of SCB for managing persistent cytopenias after T-cell–redirecting therapies and supports the importance of early stem cell collection.
Keywords: BCMA, bispecific antibody, Cytopenia, elranatamab, Hematopoietic Recovery, Multiple Myeloma, Stem cell boost
Received: 15 Sep 2025; Accepted: 16 Dec 2025.
Copyright: © 2025 Akiyama, Kakiuchi, Sakamoto, Tomigaki, Fujioka, Harima, Niwa, Takagi, Kozuki, Miyata, Yoshihara, Yoshihara and Iwata. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Seiji Kakiuchi
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