Multicenter Clinical Trial of Neoadjuvant Therapy for Locally Advanced Rectal Cancer by Chemoradiation Combined with Metformin

Multicenter Phase I/II Trial of Neoadjuvant Therapy for Locally Advanced Rectal Cancer by Chemoradiation Combined with Metformin - RC-COMET Study

Status

Active, not recruiting

Phases

Phase 2

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCTs011200001

Enrollment

Registered

2020-07-10

Start date

2020-08-05

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Rectal cancer

Interventions

Neoadjuvant chemoradiotherapy (capecitabine and 50.4 Gy radiation) with metformin for rectal cancer in patients without diabetes mellitus

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Rectal adenocarcinoma on biopsy of the primary tumor 2. Lower edge of the rectal cancer is less than 15 cm from the anal verge before chemoradiotherapy 3. Clinical T3-4NanyM0 before chemoradiotherapy 4. Resectable rectal cancer before chemoradiotherapy 5. Aged between 20 and 75 years 6. Eastern Cooperative Oncology Group Performance Status score of 0 7. Meeting each of the following parameters: white blood cell count: 3,000/mm3 or higher; neutrophil count: 2,000/mm3 or higher; hemoglobin level: 9.0 g/dL or higher; platelet count: 100,000/mm3 or higher; total bilirubin level: less than 2.0 mg/dL; and the ratio of aspartate aminotransferase and alanine aminotransferase: less than 3 times the normal upper value 8. Written informed consent

Exclusion criteria

Exclusion criteria: 1. Multiple primary cancers 2. Recurrent rectal cancer 3. History of chemoradiotherapy to the pelvis 4. Inflammatory bowel disease 5. Pulmonary fibrosis or interstitial pneumonia 6. Myocardial infarction or severe heart failure 7. Renal failure (creatinine level of >1.4 mg/dL in men and >1.3 mg/dL in women or a creatinine clearance rate of 6.5% or drug treatment) 9. Uncontrolled systemic infection 10. Pregnancy or lactation 11. Psychosis or mental symptoms that could make it difficult for patients to participate in the trial 12. Drug allergies to capecitabine and metformin 13. Patients not willing or able to follow the study protocol 14. Other inadequate conditions for the trial

Design outcomes

Primary

Measure	Time frame
Dose-limiting toxicity (Phase I) Pathological complete response rate considering the central pathological diagnosis (Phase II)	—

Secondary

Measure	Time frame
Pathological complete response rate considering the domestic pathological diagnosis Objective response rate R0 resection rate Disease-free survival Recurrence site Overall survival Completion rate of the protocol treatment Adverse events Postoperative complications	—

Contacts

Public ContactKen Imaizumi

Hokkaido University Hospital

imaken1983@gmail.com+81-11-706-5927

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026