Nocardia Rubra Cell Wall Skeleton in Combination With Prior Second- or Third-line Regimens for the Treatment of Potentially Hazardous Colorectal Cancer SD Status

Inclusion Criteria: 1. Age ≥ 18 years old, gender is not limited; 2. Colorectal adenocarcinoma confirmed by pathologic histology and/or cytology and imaging; 3. Have 1 or more measurable lesions with a longest diameter of at least 10 mm as determined by spiral CT scanning; and a diameter of at least 20 mm as determined by conventional CT scanning (Criteria for the Evaluation of Efficacy in Solid Tumors, i.e., RECIST Criteria, version 1.1); 4. Prior second- or third-line therapy for advanced or metastatic colorectal cancer with potentially harmful SD status. The potentially hazardous SD (Stable Disease) state is defined as an increase in SLD (Sum of Longest Diameters) by less than 20% according to RECIST 1.1 criteria, with an absolute increase of SLD ≤ 5mm from the nadir; a serum CEA (Carcinoembryonic Antigen) level below 10.0 ng/ml during stable disease, with two consecutive measurements of 10 ng/ml or more (with a testing interval of at least one month); or a serum CEA level of 10 ng/ml or more during stable disease, with a gradual increase in CEA after two consecutive measurements (with a testing interval of at least one month); a serum CA19-9 level below 60.0 ng/ml during stable disease, with two consecutive measurements of 60 ng/ml or more (with a testing interval of at least one month); or a serum CEA level of 60 ng/ml or more during stable disease, with a gradual increase in CEA after two consecutive measurements (with a testing interval of at least one month). Meeting any one of the above criteria can be considered as the presence of a potentially hazardous SD state. 5. The general condition score of the Eastern Cooperative Oncology Group (ECOG) is 0 or 1; 6. Expected survival ≧3 months; 7. Blood, liver and kidney function within 7 days prior to screening: absolute neutrophil count ≥ 1.5 x 109 /L; hemoglobin ≥ 9.0 g/dl; platelet count ≥ 100 x 109 /L; total bilirubin ≤ 1.5 times the upper limit of normal (ULN); gammaglutaminase and gammaglutaminase ≤ 3.0 x ULN (≤ 5 x ULN for patients with hepatic metastases); alkaline phosphatase ≤ 3 x ULN. phosphatase ≤ 3 x ULN (≤ 5 x ULN in patients with liver metastases); serum creatinine ≤ 1.5 x ULN; 8. Agreed to sign the informed consent form; Exclusion Criteria: 1. Allergic constitution; 2. With comorbid diabetes; 3. Active clinically severe infection; 4. Any other conditions deemed exclusionary by the investigator.