mRNA-encoded antibodies show early clinical promise in cancer therapy

Antibody-based therapeutics have become a cornerstone of modern cancer treatment, with more than 80 Food and Drug Administration-approved secreted proteins and seven chimeric antigen receptor (CAR) cell therapies now available for various malignancies. Since the introduction of rituximab, the field has moved from conventional IgG monoclonal antibodies toward increasingly sophisticated formats, including antibody-drug conjugates, degrader antibody-conjugates, Fc-engineered antibodies, and bispecific constructs. Immune checkpoint inhibitors targeting PD-1, PD-L1, and CTLA-4 now dominate clinical practice, underscoring how far antibody engineering has reshaped oncology. Yet a new review published in the Journal of Translational Medicine argues that the next leap may come not from refining these molecules in the lab, but from letting the patient’s own cells manufacture them in vivo, using messenger RNA as the blueprint.

The central limitation of current approaches, the review’s authors note, is manufacturing. Recombinant antibodies and CAR cell therapies require complex production pipelines, high costs, and time-consuming processes that limit scalability and flexibility. mRNA-based technologies offer an alternative route: delivered via lipid nanoparticles or related systems, therapeutic mRNA can be translated directly by the recipient’s cells, producing the desired protein transiently. In the antibody space, this means mRNA-encoded constructs can drive transient synthesis of full-length IgGs, bispecific T-cell engagers, and multiplexed antibody formats inside the body, with expression levels that can be tuned by dose.

The clinical proof of concept came with mRNA-1944 (NCT03829384), the first mRNA-encoded monoclonal antibody dosed in humans. That trial demonstrated dose-dependent therapeutic IgG expression in vivo, establishing that lipid nanoparticle delivery can produce clinically meaningful antibody levels from a synthetic transcript. Oncology has now produced the platform’s first efficacy signal: BNT142 (NCT05262530), an mRNA-encoded bispecific antibody, achieved disease control in more than half of treated patients with solid tumors, including partial responses in ovarian cancer. According to the review, this marked the first clinical efficacy signal for the mRNA-encoded antibody platform, a milestone that positions the modality alongside, rather than behind, conventionally manufactured biologics.

The review also highlights an emerging frontier at the interface of RNA therapeutics and targeted protein degradation. Conventional degrader antibody-conjugates depend on chemical conjugation of antibody scaffolds to non-encoded degrader payloads, a chemistry-intensive process. Recent efforts to develop mRNA-based degrader strategies suggest that the junction between antibody delivery, RNA therapeutics, and targeted protein degradation is beginning to expand, potentially allowing degrader molecules to be produced in vivo from encoded templates rather than assembled synthetically.

Beyond protein delivery, mRNA is being used to transiently express chimeric antigen receptors in immune cells, enabling non-integrating engineering of T cells, natural killer cells, or macrophages. These approaches support both ex vivo and in vivo generation of CAR-expressing cells, extending the scope of mRNA therapeutics from protein replacement to cellular reprogramming. mRNA-electroporated CAR T cell trials, including NCT01355965 targeting mesothelin, established clinical feasibility for the ex vivo route, in which a patient’s T cells are engineered outside the body and reinfused. More recently, a circular mRNA-based CAR-T product, UCMYM802 from China, in patients with advanced solid tumors became the first of its kind to enter clinical testing, pointing toward an in vivo future in which the engineering step itself could occur inside the patient.

The review’s authors conclude that versatility, rapid design, and tunable expression profiles position mRNA as a programmable platform for next-generation cancer immunotherapies, one capable of integrating antibody-based, conjugate-based, and cell-based modalities within a single delivery technology. If the early clinical signals from mRNA-1944 and BNT142 are borne out in larger trials, the manufacturing bottleneck that has constrained antibody and CAR therapy access could give way to a model in which a designed transcript, rather than a bioreactor, delivers the therapeutic payload.

Subject of Research: mRNA-encoded antibodies and mRNA-based cellular reprogramming in cancer therapy

Article Title: mRNA encoded antibodies in cancer therapy: molecular design, engineered formats, and cellular reprogramming

Article References: Gallo, S., Folco, C. B., Bonechi, C., Limana, F., & Crepaldi, T. (2026). mRNA encoded antibodies in cancer therapy: molecular design, engineered formats, and cellular reprogramming. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-09129-3

Image Credits: AI Generated

DOI: 10.1186/s12967-026-09129-3

Keywords: mRNA therapeutics, lipid nanoparticles, monoclonal antibodies, bispecific antibodies, CAR T cells, cancer immunotherapy, antibody-drug conjugates, targeted protein degradation, immune checkpoint inhibitors, clinical trials, mRNA, encoded