Cancer Cell | Fc-Optimized CD40 Agonistic Antibody Induces Tertiary Lymphoid Structure Formation and Activates Systemic Antitumor Immunity

This study provides a novel clinical strategy for local immunotherapy of advanced solid tumors. By optimizing the antibody Fc domain and employing intratumoral injection, it effectively circumvents the systemic toxicity associated with conventional CD40 agonists while eliciting durable systemic antitumor immunity. This approach offers significant implications for the field of cancer immunotherapy, particularly in overcoming the immunologically “cold” tumor microenvironment.

 

Literature Overview

The article “Fc-optimized CD40 Agonistic Antibody Elicits Tertiary Lymphoid Structure Formation and Systemic Antitumor Immunity in Metastatic Cancer,” published in Cancer Cell, systematically investigates the safety, pharmacokinetics, and preliminary antitumor activity of the Fc-engineered CD40 agonistic antibody 2141-V11 in patients with advanced metastatic cancer. Combining a phase I clinical trial with humanized mouse models, the study reveals that intratumoral administration of this antibody induces tertiary lymphoid structure (TLS) formation, thereby promoting CD8+ T cell activation and systemic antitumor immunity. The research not only underscores the importance of synergistic optimization of administration route and antibody engineering but also offers new insights into immunotherapeutic interventions for refractory tumors.

Background Knowledge

Currently, CD40, a key co-stimulatory receptor on dendritic cells (DCs) and other antigen-presenting cells, is a central target for activating adaptive immune responses. However, early systemically administered CD40 agonists caused dose-limiting toxicities such as cytokine release syndrome and thrombocytopenia, with limited efficacy, hindering clinical translation. The major challenge lies in enhancing CD40 signaling strength while avoiding systemic immune activation-induced toxicity. Recent findings indicate that the binding of CD40 antibody Fc domains to the inhibitory receptor FcγRIIB is crucial for effective cross-linking and downstream signal activation, offering a new direction for antibody engineering. This study leverages this mechanism by designing an Fc-optimized human IgG1-CD40 antibody, 2141-V11, with high affinity for FcγRIIB, and employs intratumoral injection to locally activate the immune microenvironment while minimizing systemic exposure. Furthermore, TLS formation is recognized as a positive biomarker for antitumor immunity, yet effective induction remains challenging. By linking CD40 agonism with TLS generation, this study provides a novel mechanistic pathway to improve immunotherapy response rates.

 

 

Research Methods and Experiments

The study conducted a single-center, open-label phase I clinical trial (NCT04059588), enrolling 12 patients with advanced solid tumors who received intratumoral injections of 2141-V11 at varying doses (0.7–10.0 mg) to evaluate safety, pharmacokinetics, and preliminary efficacy. Tumor responses were assessed using RECIST v1.1 and itRECIST criteria, with immunophenotypic analyses performed on patient blood and tumor biopsy samples. To investigate the underlying mechanisms, the research team utilized humanized hCD40/hFcγR mouse models implanted with E0771 breast cancer or MB49 bladder cancer cells, simulating intratumoral or intravesical administration. Single-cell RNA sequencing (scRNA-seq), multiplex immunofluorescence (mIF), and TCR sequencing were employed to systematically analyze immune cell dynamics and TLS formation within the tumor microenvironment. Key experiments included: validating 2141-V11's ability to induce TLS in hCD40/hFcγR mice; using FTY720 to block lymphocyte egress from draining lymph nodes (tdLNs) to determine whether T cell activation depends on tdLNs; and assessing the functional necessity of B cells in the antitumor response through B cell depletion experiments.

Key Conclusions and Perspectives

• 2141-V11 demonstrated a favorable safety profile in patients, with no dose-limiting toxicities observed and no maximum tolerated dose (MTD) reached within the 0.7–10.0 mg range, indicating that intratumoral injection effectively avoids the systemic toxicity of CD40 agonists and establishes a safe dosing window for future clinical development.
• Two patients achieved complete responses—one with melanoma and one with HR+ breast cancer—and tumor regression occurred not only at injected sites but also at non-injected lesions, suggesting that 2141-V11 induces systemic antitumor immunity, offering a new approach to achieve the “abscopal effect” in cancer immunotherapy.
• In patients achieving complete response, mature TLS containing B cells, T cells, and dendritic cells formed post-injection, and TLS development correlated positively with CD8+ T cell clonal expansion, suggesting TLS may serve as a histological marker of local immune activation and guide response prediction.
• In hCD40/hFcγR mouse models, 2141-V11 induced de novo TLS formation in injected tumors and promoted the differentiation of cDC1s into mregDCs, a process dependent on FcγRIIB-mediated cross-linking, highlighting the critical role of antibody engineering in functional activity.
• Although B cells heavily infiltrated TLS, B cell depletion experiments showed they were not essential for 2141-V11's antitumor effect, suggesting B cells may act primarily as structural scaffolds rather than effector cells—a finding with implications for designing combination therapies targeting B cells.
• Blocking tdLN egress with FTY720 completely abrogated antitumor effects in non-injected tumors, indicating that 2141-V11 can drive T cell activation within TLS independently of tdLNs, providing theoretical support for developing novel vaccine strategies that do not rely on conventional lymph nodes.

Research Significance and Prospects

This study represents a paradigm shift in the clinical development of CD40-targeted therapies: by combining Fc engineering with localized delivery, it achieves a balance between safety and efficacy. This strategy is particularly suitable for injectable metastatic lesions such as those in the skin or lymph nodes, offering a feasible pathway to convert “cold” tumors into “hot” ones. Future studies may explore combination therapies of 2141-V11 with PD-1 inhibitors to further enhance T cell function. Additionally, TLS formation could serve as a potential biomarker for patient selection, advancing the development of precision immunotherapy.

 

 

Conclusion

This study successfully overcame the systemic toxicity challenges of traditional CD40 agonists by innovatively optimizing the Fc domain of the CD40 antibody and employing intratumoral injection, enabling safe clinical application in patients with metastatic cancer and inducing durable systemic antitumor immunity. The key mechanism involves 2141-V11 promoting the formation of tertiary lymphoid structures (TLS) within the tumor microenvironment, thereby establishing local immune activation hubs that initiate CD8+ T cell responses independently of draining lymph nodes. This finding not only reveals the central role of TLS in antitumor immunity but also opens new avenues for immunotherapy of refractory solid tumors. From bench to bedside, this research lays a solid foundation for developing “in situ vaccine” strategies based on local immune activation, potentially transforming the treatment landscape for patients with advanced cancer, especially those unresponsive to current immune checkpoint inhibitors. In the future, integrating biomarker-based patient selection with combination therapies will accelerate the clinical translation of this approach and enhance overall therapeutic outcomes.

 

Juan C Osorio, David A Knorr, Polina Weitzenfeld, Mark E Robson, and Jeffrey V Ravetch. Fc-optimized CD40 Agonistic Antibody Elicits Tertiary Lymphoid Structure Formation and Systemic Antitumor Immunity in Metastatic Cancer. Cancer cell.