SOFIE Doses First Patient in Landmark Phase 3 Trial for Advanced Cancer Imaging

DULLES, VA – December 29, 2025 – In a significant step forward for oncology and precision medicine, SOFIE Biosciences announced today that the first patient has been dosed in its pivotal Phase 3 clinical trial, FAPI-GO. The study evaluates [18F]FAPI-74, a novel radiopharmaceutical designed to provide a new and potentially more accurate way of detecting gastroesophageal cancers through Positron Emission Tomography (PET) imaging.

The milestone dosing, which took place at a RadNet facility in Los Angeles, marks the official launch of patient evaluation in one of two major late-stage trials for the promising imaging agent. The effort is a collaboration between SOFIE, the imaging network giant RadNet, and the clinical trial and oncology care partnership of Helios Clinical and The Oncology Institute of Hope and Innovation.

This development brings a new class of imaging agents, known as FAPI (Fibroblast Activation Protein Inhibitor), closer to clinical reality, offering a powerful tool against cancers that are notoriously difficult to visualize and manage.

A New Target in the Tumor Microenvironment

For decades, the workhorse of cancer PET imaging has been [18F]FDG, a radiolabeled sugar molecule that is readily absorbed by metabolically active cancer cells. While effective for many tumor types, FDG-PET has limitations. Some cancers are not highly metabolic, and high background uptake of FDG in certain healthy tissues, like the brain and digestive tract, can mask the presence of malignant disease.

[18F]FAPI-74 represents a fundamental shift in strategy. Instead of targeting the metabolic activity of cancer cells, it targets a protein called Fibroblast Activation Protein (FAP). This protein is not typically found on the cancer cells themselves but is highly expressed on cancer-associated fibroblasts (CAFs), which form a major component of the tumor microenvironment, or stroma. This dense, fibrous network provides structural support for the tumor and plays a critical role in its growth, invasion, and resistance to therapy.

By targeting FAP, [18F]FAPI-74 PET scans can illuminate this stromal framework, providing a distinct and high-contrast map of the tumor's full extent. Early research has shown that this approach can detect tumors with high sensitivity and specificity, often outperforming traditional FDG-PET, particularly in cancers rich in stroma like many gastrointestinal malignancies.

"We are proud of this milestone in the continuing clinical development of FAPI," said Patrick Phelps, President and CEO of SOFIE Biosciences, in a statement. "FAPI provides a different way to image and identify disease, by targeting cancer-associated fibroblasts in the tumor microenvironment. Dosing the first patient with [18F]FAPI-74 brings us one step closer to addressing vital areas of unmet need in gastric and esophageal cancers and realizing the promise of FAPI PET in precision medicine."

The FAPI-GO Trial and Its Ambitious Goals

The newly initiated FAPI-GO (FAPI in Gastroesophageal Oncology) trial is a multi-site, open-label study designed to rigorously assess the diagnostic power of [18F]FAPI-74. The study plans to enroll approximately 200 adults with gastroesophageal cancer across 18 sites over a 24-month period.

The primary objective is to determine the sensitivity and specificity of [18F]FAPI-74 PET/CT for the detection of distant metastatic disease (M1). Accurately identifying whether cancer has spread from its primary site is one of the most critical steps in oncology, as it dictates the entire treatment strategy. For patients with localized disease, the goal is often a cure through surgery or radiation, whereas metastatic disease typically requires systemic treatments like chemotherapy or immunotherapy.

An imaging agent that can more reliably detect metastases could prevent patients from undergoing futile aggressive local therapies and ensure they receive appropriate systemic treatment sooner. Conversely, it could also confirm that a patient's disease is truly localized, giving clinicians and patients confidence in pursuing a curative treatment plan.

Expanding the Fight to Pancreatic Cancer

SOFIE's commitment to leveraging FAPI technology extends beyond gastroesophageal cancer. The company also announced the December 2025 launch of a second Phase 3 study, FAPI-PRO (FAPI in Precision Imaging of Pancreatic Cancer). This trial will follow a similar design to assess the utility of [18F]FAPI-74 PET/CT in detecting metastatic disease in adults with Pancreatic Ductal Adenocarcinoma (PDAC).

PDAC is one of the most lethal cancers, partly because it is often diagnosed at a late, metastatic stage. Its dense stromal environment makes it an ideal candidate for FAPI imaging, and a more effective diagnostic tool is desperately needed to improve outcomes for patients facing this challenging disease.

Running two major Phase 3 trials in parallel underscores SOFIE's confidence in the FAPI platform and its strategy to address some of the most significant unmet needs in cancer diagnostics.

A Collaborative Effort for Clinical Success

Bringing a novel radiopharmaceutical from the lab to a large-scale clinical trial requires a complex and powerful partnership. The dosing of the first patient was made possible by a synergy between SOFIE's development expertise and the extensive networks of its partners.

RadNet, a leading provider of diagnostic imaging services in the United States, provides the advanced imaging capabilities and clinical trial experience necessary to execute the study. "FAPI-74 is an exciting new advanced PET tracer," commented Dr. Judith Rose, RadNet's Director of PET/CT and Research. "RadNet's experience in PET/CT clinical trials, combined with our national network of advanced imaging capabilities uniquely positions us to support oncology trials to transform cancer diagnosis and treatment. It is an honor to be in the position to have enrolled and imaged, in Los Angeles, the first patient in this important Phase 3 trial."

Helios Clinical and The Oncology Institute of Hope and Innovation are instrumental in patient access and recruitment, embedding the clinical trial within a community-based oncology care network. This approach not only helps accelerate enrollment but also ensures that cutting-edge research is accessible to a broader and more diverse patient population.

This collaborative model is essential for navigating the complexities of modern drug and diagnostic development, ultimately aiming to bring innovative solutions to patients faster. As the FAPI-GO and FAPI-PRO trials progress, the oncology community will be watching closely, hopeful that this new imaging technology will soon become a standard tool in the fight against cancer.