Pomalidomide enhances CAR-T cell therapeutic efficacy and Remodels Immune Microenvironment in Lymphoid Malignancies

Background Despite the remarkable efficacy of Chimeric Antigen Receptor T-cell (CAR-T) therapy in hematological malignancies, challenges including limited persistence and T cell exhaustion hinder long-term responses. Pomalidomide, an immunomodulatory drug, shows potential to synergize with CAR-T therapy, yet its mechanistic basis remains unclear. Methods We performed CCK8, LDH, qPCR, ELISA, flow cytometry and bulk RNA-sequencing to explore the effects and mechanisms of pomalidomide on CAR-T cell in vitro . Myeloma xenograft murine models were established to evaluate the synergetic effects of CAR-T and pomalidomide in vivo . Single-cell RNA sequencing was employed to delineate the effects of pomalidomide on immune microenvironment. Results Pomalidomide (1–5 µg/mL) enhances CAR-T cell proliferation and cytotoxicity in an activation-dependent manner, upregulates the expression of interleukin-2 (IL-2), interferon-γ (IFN-γ), and chemokines CXCL9-CXCL11, and promotes the maintenance of central memory T cells (Tcm). In vivo , combination therapy induced tumor regression (p < 0.001) and extended survival (median OS: 30 days vs. unreached, p < 0.01). Transcriptomic analysis revealed metabolic reprogramming (glycolysis, fatty acid degradation) and reduced exhaustion markers (PD-1, LAG3). Single-cell sequencing demonstrated the immune microenvironment remodeling post pomalidomide treatment, including increased T/NK cells proportion and immune activity, as well as reduced myeloid-derived suppressor cell (MDSC) signatures within monocytes/macrophages. Conclusions Pomalidomide amplifies CAR-T efficacy by enhancing memory formation, cytokine production, and metabolic fitness while reshaping the immune microenvironment. These findings provide a rationale for clinical optimization of pomalidomide-CAR-T combinations in refractory hematologic malignancies.