Therapeutic Cancer Vaccines in B-Cell Malignancies and Multiple Myeloma.

Therapeutic cancer vaccines represent a rational immunotherapeutic strategy aimed at inducing tumor-specific adaptive immune responses in patients with established malignancies. In contrast to prophylactic vaccines, these approaches must function within immunosuppressive tumor microenvironments characterized by antigenic heterogeneity, immune dysfunction, and dynamic tumor evolution. Effective vaccine design requires the integration of three essential components: the selection of appropriate tumor-associated or tumor-specific antigens, efficient delivery platforms that enable antigen presentation, and adjuvant systems that promote robust T-cell priming and expansion. Initial clinical investigations in B-cell malignancies and multiple myeloma demonstrated that idiotype-based vaccines can elicit tumor-specific immune responses. However, durable clinical benefit has been inconsistent, reflecting limitations in antigen selection, suboptimal immunogenicity, and tumor-mediated immune evasion. Over the past decade, advances in tumor genomics, next-generation sequencing, and immune monitoring have enabled the development of next-generation vaccine platforms, including dendritic cell-based approaches, personalized neoantigen vaccines, and mRNA-based technologies. Emerging evidence suggests that vaccine efficacy is highly dependent on disease context. Biologically favorable settings such as minimal residual disease (MRD) and post-transplant immune reconstitution provide reduced tumor burden and improved immune competence, thereby enhancing the likelihood of effective immune priming. In parallel, combination strategies incorporating immune checkpoint inhibitors, immunomodulatory agents, and cellular therapies are increasingly being explored to overcome tumor-induced immunosuppression. This review synthesizes current knowledge of therapeutic cancer vaccines in B-cell malignancies and multiple myeloma, with emphasis on immunologic mechanisms, antigen selection, vaccine platforms, and clinical evidence. We further propose a conceptual framework integrating tumor biology, immune context, and combination strategies to guide the rational development of next-generation vaccine therapies.