Bispecific antibody therapy in multiple myeloma and risk of progressive multifocal leukoencephalopathy

CONTEXT: Bispecific antibodies (bsAbs) recently reshaped the treatment landscape of multiple myeloma (MM). Rare cases of progressive multifocal leukoencephalopathy (PML) have been reported in MM patients, and more recently in bsAbs-treated patients. OBJECTIVES: We aimed to investigate a potential safety signal for PML in patients with MM treated with bsAbs. METHODS: We included all patients with MM treated with bsAbs identified in the French prospective registry of JC polyomavirus infections of the central nervous system and/or from the French pharmacovigilance database (FPVD). We also performed a systematic review. We then assessed whether a disproportionality signal for PML reporting exists, comparing bsAbs and other MM therapies in VigiBase®, the world pharmacovigilance database. RESULTS: In the registry-FPVD cohort, 14 patients were included; all had at least triple-refractory MM, with a median disease duration of 13 years (IQR, 10-14) and were exposed to BCMA-targeting bsAbs (median time to PML diagnosis: 22 months, IQR, 12-24); 10 (71%) were in complete response. Main clinical manifestations included motor deficit, cognitive impairment and visual symptoms (8/14 patients each, 57%). Twelve (86%) had died from PML by month 12. Similar features and outcomes were observed in the systematic review (n=14 cases). PML reporting was significantly higher with bsAbs than with other MM therapies (Reporting Odds Ratio 17.7; 95% CI, 12.1-26.1). INTERPRETATION: PML may represent an emerging complication in patients with MM receiving bsAbs. Vigilant monitoring and rapid assessment of new neurological deficits are critical in this population.

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Journal
Blood Advances
Published
2026-06-12
DOI
https://doi.org/10.1182/bloodadvances.2026020556
Primary Topic
Polyomavirus and related diseases
Type
article
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article

Bispecific antibody therapy in multiple myeloma and risk of progressive multifocal leukoencephalopathy

Yassine Taoufik, Margaux Lafaurie, Éolia Brissot, Bruno Lioure et al.
Blood Advances
Polyomavirus and related diseases
article

Bispecific antibody therapy in multiple myeloma and risk of progressive multifocal leukoencephalopathy

Yassine Taoufik, Margaux Lafaurie, Éolia Brissot, Bruno Lioure, Guillaume Martin‐Blondel, Clément Javaux, Elena-Camelia Rusu, Natalia Shor, Piero Schirò, Fabrice Bonneville, Danièle Bensoussan, C Richaud, Nicolas Weiss, Sébastien Lhomme, Emmanuel Treiner, Kévin Bihan, Anne-Sophie L’Honneur, Simon Herbel, Agnès Sommet, Aurore Perrot, Loïc Le Guennec, Damien Roos‐Weil, François Coustillères, Thomas Wirth, Baptiste Liévin, Pierre-Antoine Limouzin, P. Petitgas, Jacques Gasnault, Béatrice Pignolet, Jean-Roch Le Henaff, Valérie Pourcher, Julien Le Guen, Bruno Stankoff, Laura Maerten
article en

Abstract

CONTEXT: Bispecific antibodies (bsAbs) recently reshaped the treatment landscape of multiple myeloma (MM). Rare cases of progressive multifocal leukoencephalopathy (PML) have been reported in MM patients, and more recently in bsAbs-treated patients. OBJECTIVES: We aimed to investigate a potential safety signal for PML in patients with MM treated with bsAbs. METHODS: We included all patients with MM treated with bsAbs identified in the French prospective registry of JC polyomavirus infections of the central nervous system and/or from the French pharmacovigilance database (FPVD). We also performed a systematic review. We then assessed whether a disproportionality signal for PML reporting exists, comparing bsAbs and other MM therapies in VigiBase®, the world pharmacovigilance database. RESULTS: In the registry-FPVD cohort, 14 patients were included; all had at least triple-refractory MM, with a median disease duration of 13 years (IQR, 10-14) and were exposed to BCMA-targeting bsAbs (median time to PML diagnosis: 22 months, IQR, 12-24); 10 (71%) were in complete response. Main clinical manifestations included motor deficit, cognitive impairment and visual symptoms (8/14 patients each, 57%). Twelve (86%) had died from PML by month 12. Similar features and outcomes were observed in the systematic review (n=14 cases). PML reporting was significantly higher with bsAbs than with other MM therapies (Reporting Odds Ratio 17.7; 95% CI, 12.1-26.1). INTERPRETATION: PML may represent an emerging complication in patients with MM receiving bsAbs. Vigilant monitoring and rapid assessment of new neurological deficits are critical in this population.

Blood Advances
Hôpital Necker-Enfants Malades (FR), Université Toulouse III - Paul Sabatier (FR), Inserm (FR), Université Fédérale de Toulouse Midi-Pyrénées (FR), Centre Hospitalier Universitaire de Toulouse (FR), Sorbonne Université (FR), Université Sorbonne Paris Nord (FR), Centre Hospitalier Universitaire de Tours (FR), Assistance Publique – Hôpitaux de Paris (FR), Hospices Civils de Lyon (FR), Hôpital Européen Georges-Pompidou (FR), Hôpital Saint-Antoine (FR), Hôpital Européen (FR), Délégation Centre-Est (FR), Hôpital Pellegrin (FR), Centre Hospitalier de Cornouaille (FR), Pitié-Salpêtrière Hospital (FR), Centre Hospitalier Universitaire de Clermont-Ferrand (FR), Hôpitaux Universitaires de Strasbourg (FR), Bicêtre Hospital (FR), Université de Strasbourg (FR)
Good health and well-being
Openalex Percentile: Top 7%
Polyomavirus and related diseases
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