Daratumumab and lenalidomide (DR) combination therapy has improved outcomes in multiple myeloma (MM), but some patients still experience poor responses. To understand the factors influencing treatment resistance, we performed single-cell RNA sequencing on bone marrow samples from 21 newly diagnosed MM patients enrolled in the IFM2017-03 trial, classifying them as complete responders (CR, n=11) or non-/poor responders (NR, n=10). NR patients exhibited pro-inflammatory bone marrow microenvironment (BME) characterized by elevated cytokine signaling. Classical and Nonclassical monocytes in NR patients displayed gene expression signals associated with impaired phagocytosis and interferon-associated monocytes upregulated NF-kB-related genes, while CD54dim NK cells in NR patients expressed lower levels of CD16, a marker associated with antibody-dependent cellular cytotoxicity. Furthermore, tumor cells from NR patients also showed enhanced NF-kB activation, which was correlated with increased inflammatory gene expression and poor prognosis. A random forest model based on 34 NF-kB-related genes accurately distinguished CR from NR patients (AUC = 0.96), and a refined model using the top eight genes maintained strong predictive power for bone marrow (AUC = 0.92) and peripheral blood samples (AUC = 0.77). These findings suggest that an inflamed BME and NF-kB signaling contribute to DR resistance, offering potential targets for overcoming poor responses.

The authors have declared no competing interest.

NCT03993912

This study was founded by Johnson and Johnson.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The French National Agency for the Safety of Medicines and Health (ANSM) and the Ethical Committee "Sud-Mediterranee II" (reference 219 A10) approved the protocol (ID# 19.02.28.43641). The IFM2017-03 trial (NCT03993912) and the correlative studies were conducted in accordance with the principles of the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines. All the patients provided written informed consent. The trial was promoted by Lille University Hospital (CHU Lille) in collaboration with the IFM and with the support of Johnson and Johnson.

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

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All single-cell RNA, surface protein, and bulk sequencing data generated in this study have been deposited in the European Genome-phenome Archive (EGA) under the reference XXXX. The publicly available scRNA-seq dataset from 20 healthy individuals (GSE120221) was used for comparison. All R code used for the analysis is available on GitHub at https://github.com/Chengwenwen1/MM-France/tree/main.