Skip to main content
 
Notice: Users may be experiencing issues with displaying some pages on stanfordhealthcare.org. We are working closely with our technical teams to resolve the issue as quickly as possible. Thank you for your patience.
Stanford Health Care

Dynamics of BCMA expression in patients with relapsed/refractory multiple myeloma receiving BCMA-directed CAR-T therapy.

Dynamics of BCMA expression in patients with relapsed/refractory multiple myeloma receiving BCMA-directed CAR-T therapy. Blood cancer journal Rana, M. S., Fernandez-Pol, S., Jensen, A., Hovanky, V., Velayati, A., Oak, J. S., Silva, O., Ames, E., Muffly, L. S., Sahaf, B., Arai, S., Kennedy, V. E., Bharadwaj, S., Iberri, D. J., Liedtke, M., Natkunam, Y., Shiraz, P., Weng, W. K., Smith, M., Frank, M. J., Mackall, C. L., Dahiya, S., Mikkilineni, L., Miklos, D. B., Hosoya, H., Sidana, S. 2026

Abstract

There is limited systemic data on the dynamics of BCMA-target antigen expression with BCMA CAR-T at relapse. We analyzed 76 patients receiving standard-of-care BCMA-directed CAR-T who underwent real-time BCMA expression evaluation at baseline (n = 50), relapse (6), or both (20) using flow cytometry (FC) and/or immunohistochemistry (IHC). BCMA was universally expressed at baseline with significant heterogeneity in expression level. No concordance was seen between FC and IHC in categorizing high vs. low expression (Spearman: 0.07, Cohen kappa: 0). Plasma cell BCMA expression by FC correlated with clinical outcomes, whereas IHC did not. High BCMA expression by FC was associated with increased likelihood for VGPR/CR (p = 0.007) and longer time to progression (p = 0.005), including the ciltacabtagene autoleucel cohort (median: 23.0 vs. 7.7 months, p = 0.02). Relapsed patients retained BCMA expression by FC, though 29% (5/16) had BCMA loss by IHC, with 4/5 showing concurrent positive BCMA expression by FC. BCMA expression at relapse by FC was significantly lower than baseline (p = 0.04); downregulation (≥25% decrease) occurred in 50% (8/16) with paired samples. Higher BCMA expression by FC correlated with higher likelihood of deep, durable responses following BCMA-directed CAR-T. While BCMA loss is rare, decreased expression is common at relapse, with implications for sequencing BCMA-directed therapies.

View details for DOI 10.1038/s41408-026-01474-2

View details for PubMedID 41935039