June 9, 2026 — Jinan, China — VitsGen and Shandong Cancer Hospital and Institute, affiliated with Shandong First Medical University, successfully held the kick-off meeting for an investigator-initiated trial (IIT) evaluating ¹⁷⁷Lu-FAP-VG11 Injection for the treatment of advanced solid tumors in Jinan.

Dr. Xiaorong Sun, Director of the Department of Nuclear Medicine at Shandong Cancer Hospital and Institute, and Dr. Yanjun Wei, President of VitsGen, attended the meeting.

From “Cold” to “Hot” Tumors: Addressing Resistance to Immunotherapy

Solid tumors often contain cancer-associated fibroblasts (CAFs) within the tumor microenvironment. These cells can form a physical barrier that restricts immune-cell infiltration, contributing to a so-called “cold tumor” phenotype that responds poorly to immune checkpoint inhibitors, including PD-1/PD-L1 antibodies.

Fibroblast activation protein (FAP) is highly expressed on the membranes of CAFs in approximately 90% of epithelial tumors, while showing minimal expression in normal tissues.

¹⁷⁷Lu-FAP-VG11 is a radioligand therapy comprising the FAP-targeting ligand FAP-VG11 chelated with the radioisotope lutetium-177 (¹⁷⁷Lu). By selectively targeting FAP-expressing cells, ¹⁷⁷Lu-FAP-VG11 delivers radiation that induces DNA damage and cell death. In addition to direct cytotoxicity, the therapy may exert indirect antitumor effects on neighboring tumor cells through radiation-induced crossfire and bystander effects, as well as potentially generate additional antitumor activity through radiation-induced immune responses, including abscopal effects.

Its proposed mechanisms of action include:

Targeted tumor-cell killing: ¹⁷⁷Lu delivers ionizing radiation that induces DNA damage in tumor cells.

Immune activation: Tumor-cell death may promote antigen release and potentially convert immunologically “cold” tumors into “hot” tumors, thereby enhancing sensitivity to immunotherapy.

Potential combination benefits: ¹⁷⁷Lu-FAP-VG11 may be combined with immunotherapy, chemotherapy, targeted therapy, and other treatment modalities to potentially achieve synergistic antitumor effects.

This mechanism provides a new rationale for combination treatment strategies in patients with advanced solid tumors.

As a next-generation targeted radionuclide conjugate, ¹⁷⁷Lu-FAP-VG11 has demonstrated several favorable characteristics in preclinical studies, including:

Higher target-binding affinity, supporting enhanced tumor targeting;

Higher tumor uptake and prolonged tumor retention, potentially enabling sustained therapeutic exposure;

Lower renal exposure, with a favorable tumor-to-kidney ratio that may help reduce the risk of renal toxicity; and

Robust antitumor activity, with greater tumor growth inhibition than comparator treatments at the same dose in animal models, together with favorable tolerability.

Dosimetry estimates based on a projected human dose of 7.4 GBq showed that absorbed radiation doses in key organs, including the kidneys, small intestine, salivary glands, and bone marrow, remained within tolerable limits, supporting the therapy’s potential safety profile.

These findings suggest that ¹⁷⁷Lu-FAP-VG11 may have the potential to achieve comparable or improved efficacy at lower doses, or reduced adverse effects at equivalent doses, potentially providing a more favorable benefit-risk profile for patients with advanced solid tumors.

Patient Population

Based on currently available clinical immunohistochemistry (IHC) scoring and FAP PET imaging data, the study will prioritize enrollment of patients with tumor types showing moderate-to-high FAP expression, including:

pancreatic ductal adenocarcinoma, non-small cell lung cancer, HR-positive/HER2-negative metastatic breast cancer, HER2-positive metastatic breast cancer, triple-negative breast cancer, soft tissue sarcoma, esophageal cancer, cholangiocarcinoma, and urothelial carcinoma of the bladder.

Pancreatic ductal adenocarcinoma, for example, is a representative “cold tumor” characterized by an exceptionally dense stromal microenvironment with high FAP expression. Conventional chemotherapy and antibody-drug conjugates (ADCs) may have limited penetration through this dense fibrotic stroma, resulting in low intratumoral drug concentrations.

FAP-targeted radioligand therapy may instead leverage this stromal “barrier” as a target-rich compartment. By targeting FAP-expressing components of the tumor microenvironment, ¹⁷⁷Lu-FAP-VG11 may disrupt tumor-supporting stroma and the microenvironment involved in tumor vascularization and nutrient supply. Through targeted cytotoxicity, bystander effects, immune activation, and potential sensitization to combination therapies, the treatment may provide both single-agent antitumor activity and synergistic effects with other therapeutic modalities.

Advancing Clinical Development with Scientific Rigor

The study has received approval from the Ethics Committee of Shandong Cancer Hospital and Institute and will be conducted in strict accordance with Good Clinical Practice (GCP) requirements to protect the rights, safety, and well-being of study participants.

The trial uses an accelerated titration design followed by a conventional 3+3 dose-escalation design, with three dose levels of 3.7 GBq, 5.55 GBq, and 7.4 GBq. Safety and pharmacokinetic characteristics will be monitored throughout the study. Trial-related examinations will be provided at no cost to participants, who will also receive transportation and nutritional support as well as clinical trial insurance coverage.

VitsGen: Advancing Innovative Radiopharmaceuticals to Transform Cancer Diagnosis and Treatment

The successful initiation of this study marks another important step in VitsGen’s continued development of radioligand therapies.

Guided by its vision to develop targeted radionuclide conjugates, transform cancer diagnosis and treatment, and help patients with cancer regain a better quality of life, VitsGen will continue to invest in innovative radiopharmaceutical R&D and advance the development of more precise and safer targeted radionuclide therapies, with the goal of bringing new treatment opportunities and hope to more patients and their families.

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