Colorectal Cancer, Microsatellite Instability High, Mismatch Repair Deficiency
Conditions
Keywords
PD-1 blockade, Toripalimab, COX-2 inhibitor, Celecoxib, Non-operative Management
Brief summary
The PICC-3 study is a multicentre, single-arm, phase II trial evaluating toripalimab plus celecoxib in patients with mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) locally advanced colorectal cancer. The trial uses a response-adapted treatment strategy, whereby patients with clinical complete response (cCR) after therapy may enter a non-operative management pathway, while patients without cCR proceed to surgery. Response assessment is based on imaging, endoscopy, biopsy evaluation, and ctDNA analysis.
Detailed description
Patients with dMMR/MSI-H locally advanced colorectal cancer have shown high sensitivity to neoadjuvant immune checkpoint inhibitor. Several phase II studies have demonstrated high rates of clinical complete response (cCR) and pathological complete response (pCR), supporting the feasibility and safety of immunotherapy in localized dMMR/MSI-H colorectal cancer. Radical surgery for locally advanced colorectal cancer is associated with substantial perioperative morbidity and long-term functional consequences. In particular, total mesorectal excision for rectal cancer may result in bowel, urinary, and sexual dysfunction, and some patients may require temporary or permanent stoma formation. Therefore, organ preservation and non-operative management have become important treatment goals for selected patients with colorectal cancer who achieve complete clinical response after neoadjuvant therapy. Previous studies have demonstrated the feasibility and safety of non-operative management after immune checkpoint inhibitor in patients with dMMR/MSI-H rectal cancer, while emerging evidence suggests that this strategy may also be feasible in selected patients with colon cancer following immunotherapy.
Interventions
DRUGToripalimab plus celecoxib
Toripalimab is administered intravenously at 3 mg/kg over 30 minutes once every 2 weeks for a total of 12 doses. Celecoxib is administered orally at 200 mg twice daily for 6 months.
PROCEDURENon-operative management
Patients achieving clinical complete response (cCR) according to comprehensive response assessment, including imaging, endoscopy, digital rectal examination (if applicable), and ctDNA evaluation, may undergo non-operative management.
PROCEDURECurative-intent surgery
Patients who do not achieve cCR will undergo curative-intent surgery.
Sponsors
Sun Yat-sen University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Masking description
Open Label
Intervention model description
Prospective, Multicenter, Single-arm, Phase II
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Signed informed consent and willingness/compliance with study procedures. 2. Age ≥18 years. 3. Histologically confirmed colorectal adenocarcinoma. 4. ECOG performance status 0-1. 5. Locally advanced primary tumor (T3/T4 and/or N+) confirmed by CT/MRI (pelvic MRI for rectal cancer). 6. dMMR (IHC) or MSI-H (PCR) status. 7. No prior anti-cancer therapy for colonrectal cancer (surgery/chemotherapy/targeted therapy/radiation). 8. Adequate organ function 9. For women of childbearing potential: negative pregnancy test and contraception use during and for 3 months post-treatment. Male participants with fertile partners must use contraception. 10. Willingness to adhere to study requirements.
Exclusion criteria
1. Presence of distant metastases (M1) confirmed by CT/MRI or PET-CT (at least covering the chest, abdomen, and pelvis). 2. Complete intestinal obstruction, active bleeding, or perforation requiring emergency surgery. 3. Inability to achieve complete resection of the primary colorectal tumor. 4. History or concurrent active malignancy (except malignancies cured ≥5 years ago or adequately treated carcinoma in situ). 5. Prior treatment with anti-PD-1/PD-L1 antibodies, anti-CTLA-4 antibodies, or other drugs/antibodies targeting T-cell co-stimulation or checkpoint pathways. 6. Major surgery (e.g., laparotomy, thoracotomy, organ resection via laparoscopy) or severe trauma within 4 weeks before enrollment (surgical incision must be fully healed). 7. Thromboembolic events (e.g., cerebrovascular accident, transient ischemic attack, pulmonary embolism, deep vein thrombosis) within 12 months before enrollment. 8. Active coronary artery disease, severe/unstable angina, or newly diagnosed angina/myocardial infarction within 12 months before enrollment. 9. New York Heart Association (NYHA) Class II or higher congestive heart failure (see Appendix 3). 10. HIV infection, AIDS, or untreated active hepatitis (HBV-DNA ≥500 IU/mL; HCV-RNA above detection limit). 11. Active inflammatory bowel disease or other colorectal disorders causing chronic diarrhea. 12. Active, known, or suspected autoimmune disease (exceptions: stable conditions like type 1 diabetes, hypothyroidism on hormone replacement, or skin disorders without systemic treatment, e.g., vitiligo, psoriasis, alopecia). 13. Interstitial lung disease, non-infectious pneumonitis, or uncontrolled systemic diseases (e.g., diabetes, hypertension, pulmonary fibrosis, acute pneumonia). 14. Residual toxicity ≥Grade 2 (per CTCAE v5.0) from prior therapies (except anemia, alopecia, skin pigmentation). 15. Known or suspected hypersensitivity to any study-related drugs. 16. Pregnancy or lactation. 17. Women of childbearing potential (last menstruation \<2 years ago) or fertile men unwilling to use effective non-hormonal contraception. 18. Any unstable medical condition compromising safety or protocol compliance.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Event-free survival (EFS) | 3 years | the time from the first dose of study treatment to the occurrence of one of the following events: locally progressive disease of the primary tumour precluding curative-intent surgery, R2 resection, local recurrence after R0 or R1 resection, unsalvageable local regrowth during non-operative management, distant metastasis, a second primary colorectal cancer, or death from any cause, whichever occurs first. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pathological complete response (pCR) rate | 3 years | the percentage of subjects with no residual viable tumor in the resected primary tumor specimen and all sampled regional lymph nodes after radical surgery (ypT0N0). |
| Clinical complete response (cCR) rate | 3 years | the percentage of subjects achieving no evidence of residual tumour on comprehensive response assessment, including imaging, endoscopy with negative biopsy findings, digital rectal examination (if applicable), and ctDNA evaluation. |
| Complete response (CR) rate | 3 years | the percentage of subjects achieving pathological complete response (pCR) after surgery or clinical complete response (cCR) with non-operative management. |
| Overall survival (OS) | 5 years | the time from the first dose of study treatment to death from any cause. |
| Incidence of treatment-related adverse events | 3 years | incidence and severity of treatment-related adverse events, graded according to CTCAE version 5.0. |
Countries
China
Contacts
CONTACTYanhong Deng, MD.
Outcome results
None listed