Selective B-cell subset depletion underlies increased infection risk in patients with MM treated with anti-BCMA vs anti-GPRC5D bsAbs

T Tomas Jelinek (Department of Hemato-oncology, University Hospital Ostrava, Ostrava, Czech Republic) D David Zihala (9Department of Hematooncology, University Hospital Ostrava and Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic) A Aintzane Zabaleta (Cancer Center Clinica Universidad de Navarra (CCUN), Centro de Investigacion Medica Aplicada (CIMA), Instituto de Investigacion Sanitaria de Navarra (IdiSNA), CIBER-ONC number CB16/12/00369, Pamplona, Spain, Pamplona, Spain) I Ioannis V. Kostopoulos (2Department of Biology, National and Kapodistrian University of Athens, Athens, Greece) O Ondrej Soucek O Ondrej Venglar (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) C Cristina Moreno D Despina Fotiou (1Department of Clinical Therapeutics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece) E Eva Radova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) L Luis Esteban Tamariz-Amador (5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain) F Foteini Theodorakakou (Department of Clinical Therapeutics, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece) L Ludmila Muronova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) A Andrea Manubens (5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain) O Ourania Tsitsilonis (National and Kapodistrian University of Athens, Athens, Greece) T Tereza Popkova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) C Carmen González A Anjana Anilkumar Sithara (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) F Francesco Corrado (9Center for Early Detection and Interception, Medical Oncology, Dana-Farber Cancer Institute, Boston, MA) N Nayda Bidikian (9Center for Early Detection and Interception, Medical Oncology, Dana-Farber Cancer Institute, Boston, MA) C Camila Guerrero (CIMA, Pamplona, Spain) V Veronika Kapustova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) D Daniel Bilek (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) P Patrick R. Hagner (10Bristol Myers Squibb, Summit, NJ) M Marta Larrayoz J Jose A. Martinez Climent (5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain) L Lucie Broskevicova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) J Jana Mihalyova (1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) M Maximilian Merz (11Myeloma Service, Memorial Sloan Kettering Cancer Center, New York, NY) T Tereza Sevcikova (4Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic) I Irene M. Ghobrial J Jesus San Miguel (5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain) M Meletios A. Dimopoulos P Paula Rodriguez-Otero J Jakub Radocha (4th Department of Internal Medicine–Hematology, University Hospital Hradec Kralove, Faculty of Medicine in Hradec Kralove, Charles University, Prague, Czech Republic) E Efstathios Kastritis B Bruno Paiva R Roman Hajek

Abstract

Abstract Infections remain a challenge during treatment of patients with multiple myeloma (MM) with anti–B-cell maturation antigen (BCMA) and anti–G protein-coupled receptor class C group 5 member D (GPRC5D) bispecific antibodies (bsAbs). However, the mechanism underlying different rates and severity of infections induced by the 2 bsAbs remains poorly understood. Single-cell RNA sequencing of bone marrow (BM) aspirates of 11 patients with MM and 8 healthy donors revealed BCMA expression on mature B cells and, surprisingly, in small pre-B cells within B-cell precursors. GPRC5D expression was restricted to malignant and less to normal plasma cells (PCs). Next-generation flow cytometry immune profiling showed that anti-BCMA bsAbs severely depleted BM mature B cells, from 4.9% to 0% (P< .001), and normal PCs, from 0.17% to <0.0002% (P< .001), during treatment of 62 patients with relapsed MM. This was observed throughout therapy. Additional flow cytometry (n = 31) and single-cell RNA sequencing studies (n = 8) demonstrated that, in contrast to anti-GPRC5D, anti-BCMA bsAbs also depleted immature and small pre-B cells. The MIcγ1 mouse model was used as a negative control of BCMA expression in all stages of the B-cell lineage, confirming no depletion of any B-cell subset after anti-BCMA treatment. In conclusion, we show that although GPRC5D bsAbs selectively target PCs, anti-BCMA bsAbs target both PCs and B cells from the small pre-B stage onward. Our study provides mechanistic insight into the increased infection risk with anti-BCMA therapy and supports individualized bsAb strategies in MM. Moreover, dual targeting of B cells and PCs may have therapeutic potential in other B-cell malignancies or autoimmune diseases.

Article Details

Journal Blood
Volume / Issue Vol. 147, Issue 10
Published March 05, 2026
Pages 1070-1082
ISSN 0006-4971
Publisher Elsevier BV

Journal Info

Blood

Elsevier BV

ISSN: 0006-4971 Health Sciences

Authors (37)

T

Tomas Jelinek

Department of Hemato-oncology, University Hospital Ostrava, Ostrava, Czech Republic

D

David Zihala

9Department of Hematooncology, University Hospital Ostrava and Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic

A

Aintzane Zabaleta

Cancer Center Clinica Universidad de Navarra (CCUN), Centro de Investigacion Medica Aplicada (CIMA), Instituto de Investigacion Sanitaria de Navarra (IdiSNA), CIBER-ONC number CB16/12/00369, Pamplona, Spain, Pamplona, Spain

I

Ioannis V. Kostopoulos

2Department of Biology, National and Kapodistrian University of Athens, Athens, Greece

O

Ondrej Soucek

O

Ondrej Venglar

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

C

Cristina Moreno

D

Despina Fotiou

1Department of Clinical Therapeutics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece

E

Eva Radova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

L

Luis Esteban Tamariz-Amador

5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain

F

Foteini Theodorakakou

Department of Clinical Therapeutics, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece

L

Ludmila Muronova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

A

Andrea Manubens

5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain

O

Ourania Tsitsilonis

National and Kapodistrian University of Athens, Athens, Greece

T

Tereza Popkova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

C

Carmen González

A

Anjana Anilkumar Sithara

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

F

Francesco Corrado

9Center for Early Detection and Interception, Medical Oncology, Dana-Farber Cancer Institute, Boston, MA

N

Nayda Bidikian

9Center for Early Detection and Interception, Medical Oncology, Dana-Farber Cancer Institute, Boston, MA

C

Camila Guerrero

CIMA, Pamplona, Spain

V

Veronika Kapustova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

D

Daniel Bilek

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

P

Patrick R. Hagner

10Bristol Myers Squibb, Summit, NJ

M

Marta Larrayoz

J

Jose A. Martinez Climent

5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain

L

Lucie Broskevicova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

J

Jana Mihalyova

1Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

M

Maximilian Merz

11Myeloma Service, Memorial Sloan Kettering Cancer Center, New York, NY

T

Tereza Sevcikova

4Department of Hematooncology, University Hospital Ostrava, Ostrava, Czech Republic

I

Irene M. Ghobrial

J

Jesus San Miguel

5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain

M

Meletios A. Dimopoulos

P

Paula Rodriguez-Otero

J

Jakub Radocha

4th Department of Internal Medicine–Hematology, University Hospital Hradec Kralove, Faculty of Medicine in Hradec Kralove, Charles University, Prague, Czech Republic

E

Efstathios Kastritis

B

Bruno Paiva

R

Roman Hajek