Toripalimab Plus Celecoxib for dMMR/MSI-H Locally Advanced Colorectal Cancer (PICC-3)

Toripalimab Plus Celecoxib With Response-adapted Non-operative Management for Mismatch Repair-deficient or Microsatellite Instability-high Locally Advanced Colorectal Cancer (PICC-3): a Multicenter, Single-arm, Phase 2 Trial

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.

Study Overview

• Status: Recruiting
• Conditions: Colorectal Cancer; Microsatellite Instability High; Mismatch Repair Deficiency
• Intervention / Treatment: Drug: Toripalimab plus celecoxib; Procedure: Non-operative management; Procedure: Curative-intent surgery

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.

• Study Type: Interventional
• Enrollment (Estimated): 105
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Yanhong Deng, MD.; Phone Number: 020-38379762; Email: dengyanh@mail.sysu.edu.cn

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510655
      • Recruiting
      • The Sixth Affiliated Hospital, Sun Yat-sen University
      • Contact: Yanhong Deng, MD.; Phone Number: 020-38379762; Email: dengyanh@mail.sysu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Toripalimab 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. Patients achieving clinical complete response (cCR) are recommended for non-operative management, whereas patients without cCR are recommended to undergo curative-intent surgery.

Drug: Toripalimab 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.; Procedure: Non-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.; Procedure: Curative-intent surgery; Patients who do not achieve cCR will undergo curative-intent surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Event-free survival (EFS)	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.	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pathological complete response (pCR) rate	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).	3 years
Clinical complete response (cCR) rate	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.	3 years
Complete response (CR) rate	the percentage of subjects achieving pathological complete response (pCR) after surgery or clinical complete response (cCR) with non-operative management.	3 years
Overall survival (OS)	the time from the first dose of study treatment to death from any cause.	5 years
Incidence of treatment-related adverse events	incidence and severity of treatment-related adverse events, graded according to CTCAE version 5.0.	3 years

Collaborators and Investigators

• Sponsor: Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2025
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): April 1, 2031

Study Registration Dates

• First Submitted: March 28, 2025
• First Submitted That Met QC Criteria: March 28, 2025
• First Posted (Actual): April 1, 2025

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: COX-2 inhibitor; Celecoxib; Toripalimab; PD-1 blockade; Non-operative Management
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Colorectal Neoplasms; Turcot syndrome; Sulfur Compounds; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Azoles; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Amides; Benzene Derivatives; Benzenesulfonamides; Sulfonamides; Sulfones; Pyrazoles; Celecoxib; toripalimab
• Other Study ID Numbers: CSWOG-C08

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No