For patients with colorectal cancer, surgical removal of the tumor is often only the first step. Despite advances in surgery and adjuvant therapies, recurrence remains a major clinical challenge. A study involving patients with stage I-II colorectal cancer found that approximately 20% of patients experienced disease recurrence within two years after treatment, highlighting the need for more effective therapeutic strategies.
In recent years, CAR-T cell therapy has emerged as one of the most rapidly advancing forms of cancer immunotherapy. Multiple clinical studies are evaluating its role in colorectal cancer, with encouraging results reported for several CAR-T targets.
Unlike conventional treatments, CAR-T cell therapy offers several potential advantages:
- CAR-T cells recognize tumor antigens directly through engineered receptors and are not restricted by major histocompatibility complex (MHC) molecules.
- CAR-T cells can expand significantly after infusion and develop memory T-cell populations that may provide long-term anti-tumor activity.
- Manufacturing processes continue to improve, making CAR-T therapies increasingly scalable and accessible.
JCO publishes promising GUCY2C CAR-T clinical trial results
On June 4, 2026, a research team led by Prof. Shen Lin and Prof. Qi Changsong from Peking University Cancer Hospital published results from a Phase I clinical trial in the prestigious Journal of Clinical Oncology (JCO). The study evaluated the safety and efficacy of a novel GUCY2C-targeted CAR-T cell therapy in patients with advanced colorectal cancer.
GUCY2C (Guanylate Cyclase 2C) is a tumor-associated antigen highly expressed in many colorectal cancers, making it an attractive target for CAR-T cell therapy.
The open-label, single-center Phase I study utilized a standard 3+3 dose-escalation design. All enrolled patients had confirmed GUCY2C-positive tumors. Four dose levels were evaluated:
- DL1: 3 × 10⁸ CAR-T cells
- DL2: 6 × 10⁸ CAR-T cells
- DL3: 12 × 10⁸ CAR-T cells
- DL4: 20 × 10⁸ CAR-T cells
The primary endpoint was safety and tolerability within 28 days following the first CAR-T cell infusion.
Encouraging clinical responses in heavily treated patients
Among 19 efficacy-evaluable patients:
- 10 patients experienced measurable tumor shrinkage.
- 5 patients achieved Partial Response (PR).
- 9 patients achieved Stable Disease (SD).
- The overall objective response rate (ORR) was 26.3%.
Notably, all objective responses occurred in the higher-dose DL3 and DL4 cohorts.
The DL3 cohort demonstrated particularly promising outcomes:
- ORR reached 40.0%.
- Median progression-free survival (mPFS) was 7.0 months.
Among patients with moderate-to-high GUCY2C expression levels:
- ORR increased to 50.0%.
- Median PFS reached 9.0 months.
These findings suggest that tumor GUCY2C expression may serve as a predictive biomarker for treatment response.
Patient case highlights durable tumor shrinkage
One notable patient (Pt09), a 60-year-old man with metastatic rectal cancer, received the DL3 dose of GUCY2C CAR-T cells.
Three months after infusion, the patient achieved a partial response. Imaging assessments revealed continuous shrinkage of both lung and liver metastases from months 1 through 9 following treatment.
Remarkably, even 12 months after CAR-T infusion, only a single liver lesion showed progression, while the remaining metastatic lesions continued to decrease in size, demonstrating durable anti-tumor activity.
Favorable safety profile observed
The therapy demonstrated a manageable safety profile.
Researchers reported:
- No dose-limiting toxicities (DLTs).
- Only one patient (5.0%) experienced Grade 3 cytokine release syndrome (CRS) and neurotoxicity.
- Eleven patients (55.0%) experienced Grade 3 diarrhea.
Based on the balance between efficacy and safety, the DL3 dose was selected for further dose-expansion studies.
Additional CAR-T approaches show promise
The JCO publication adds to a growing body of evidence supporting CAR-T therapy for colorectal cancer.
In another Phase I clinical study evaluating CEA-targeted CAR-T cells, seven of ten patients with metastatic colorectal cancer achieved stable disease, with several patients demonstrating signs of tumor reduction during follow-up.
Similarly, studies investigating GUCY2C-targeted CAR-T therapy have reported disease control rates as high as 80% in patients with metastatic colorectal cancer, while maintaining relatively mild treatment-related adverse effects.
Expanding the future of colorectal cancer treatment
Although CAR-T therapy is already transforming the treatment landscape for hematologic malignancies, its application in solid tumors has historically been more challenging. The promising results reported with GUCY2C-targeted CAR-T cells represent an important milestone in advancing cellular immunotherapy for colorectal cancer.
As clinical development continues, CAR-T therapy may become a valuable treatment option for patients with advanced, recurrent, or metastatic colorectal cancer who have exhausted conventional therapies. Larger clinical trials will be needed to confirm these early findings and further define the role of CAR-T therapy in colorectal cancer management.
