We plan to evaluate the efficacy and safety of cetuximab combined with anti-PD-1 and mFOLFOX6 in the treatment of RAS/BRAF WT locally advanced or metastatic right colon cancer

According to the World Health Organization, colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women worldwide. CRC is estimated to kill 551,269 patients worldwide each year, accounting for 5.8% of cancer deaths.Despite recent development in treatment, locally advanced or metastatic colon cancer (CC) represents a major therapeutic challenge. Presently, the standard therapeutic approach for CC is surgery and/or adjuvant chemotherapy. Nevertheless,several studies showed that neoadjuvant chemotherapy (NAC) is a more effective treatment option.Immune checkpoint inhibition (ICI) directed against programmed death-1 (PD-1) is highly effective and has become the standard of care for patients with dMMR metastatic colorectal cancers (mCRCs). In contrast, the same regimens have shown poor response rates in patients with pMMR mCRCs.Due to the high ORR rate of cetuximab combined with chemotherapy and the microenvironment with high immune infiltration of right colon cancer, it may be more sensitive to ICI.

This study consisted of two phases: phase I consisted of 25 patients; if > 11 patients responded, the trial will continue to phase II, and a total of 66 patients will be enrolled.

Inclusion Criteria:

1. RAS and BARF wild-type right colon adenocarcinoma (cecum, ascending colon, transverse colon excluding splenic flexure) confirmed by histopathology;
2. Locally advanced right colon cancer should be assessed as T3 (invading muscularis propria ≥5mm) or T4 according to abdominal CT;
3. Metastatic right colon cancer should conforms to the definition of oligometastasis of colorectal cancer in ESMO guidelines: the number of organs involved is ≤2 (occasionally 3), and the number of metastases is usually ≤5 or occasionally more.
4. At least one measurable lesion according to RECIST1.1;
5. ECOG score 0-1;
6. The expected survival time is more than 3 months;
7. Adequate organ function: total bilirubin ≤1.5 x upper limit of normal (ULN) , aspartate aminotransferase and alanine aminotransferase ≤2.5 x ULN (if patient with liver metastasis, total bilirubin ≤3 x ULN, aminotransferase and alanine aminotransferase ≤5x ULN) ,alkaline phosphatase ≤2.5 x ULN (if liver metastases≤5x ULN, if bone metastases ≤10 x ULN);LDH < 1500 U/L;Serum creatinine≤1.5 x ULN l or creatinine clearance rate ≤ 60 mL /min;ANC≥1.5×109 /L, platelet count ≥75×109 /L, Hb ≥90 g/L, WBC ≥3.0×109 /L;
8. Capable of providing informed consent, or if not capable, a legally authorized representative is capable of providing informed consent.

Exclusion Criteria:

• 1.Early stage right colon cancer. 2. Received chemotherapy or biotherapy in the past . 3. uncontrollable infection, or received antibiotic treatment within 72 hours prior to receive chemotherapy; 4. Myelodysplastic syndrome or other hematopoietic abnormalities; 5. Other malignant tumors (except carcinoma in situ and basal cell carcinoma) during this year; 6. Patients with central nervous system metastasis; 7.≥ CTCAE Grade 2 unrecovered AEs due to prior treatment (excluding anemia, hair loss, skin pigmentation).Patients with unrecovered neurotoxicity ≥ CTCAE grade 3 due to platinum-based drugs.

  8. Other diseases, such as active tuberculosis, infect HIV, AIDS, hepatitis B (patient withHBV-DNA <500IU/ml,and normal liver function can be included), positive test for hepatitis C virus, uncorrectable electrolyte disorder;ascites, pleural effusion or hydropericardium that required drainage in the past 4 weeks.With intestinal obstruction, gastrointestinal bleeding, pulmonary fibrosis or interstitial pneumonia, renal failure, hepatic failure , or cerebrovascular disease.

  9. Uncontrolled diabetes was defined as HbA1c >7.5% after the use of antidiabetic drugs, or uncontrolled hypertension was defined as systolic/diastolic blood pressure >140/90 mmHg after the use of antihypertensive drugs.

  10. Myocardial infarction,severe/unstable angina, NYHA III or IV congestive heart failure within the past 12 months.

  11. Patients who are allergic to the therapeutic drugs in this study; 12. With mental or nervous system diseases who are unable to cooperate; 13. Pregnant or lactating women;Childbearing age women refuse to accept contraceptive measures; 14.Active autoimmune disease, a history of autoimmune disease, accepting corticosteroid or immunosuppressants, or accepting hormone replacement therapy (such as thyroxine, insulin, etc).

  15. Received live vaccine within 30 days (seasonal influenza vaccine is allowed because it is inactivated) 16.Treated with any other investigational drug or participated in another interventional clinical trial within 30 days of the screening period; undergo surgery within 30 days (except for diagnostic biopsy, surgical incision should be completely healed prior to administration of the study drug).Received radiation therapy within 30 days.

  17. Other serious medical conditions made the investigator consider the patients ineligible for inclusion.