The Safety and Efficacy of the Combination of Raltitrexed for Injection and Nab-Paclitaxel in Advanced Pancreatic Cancer

Inclusion Criteria: 1. Signed informed content obtained prior to treatment; 2. The patients were confirmed as advanced pancreatic cancer by histopathology or cytology; 3. At least one measurable objective lesion was identified based on the RECIST 1.1 criteria; 4. Eastern Cooperative Oncology Group (ECOG) performance status 0-1; 5. The expected survival after surgery ≥3 months; 6. Subjects had good compliance, were able to undergo treatment and follow-up, and voluntarily followed the relevant regulations of this study; 7. No contraindications to the use of raltitrexed for injection and nab-paclitaxel; 8. Age ≥18 years and ≤75 years; 9. Subjects of child-bearing age must agree to take effective contraceptive measures during the study period; Serum or urine pregnancy tests must be negative for women of childbearing age 7 days before the start of chemotherapy, during the monthly treatment interval and after the last treatment; 10. Women must be non-lactating. Exclusion Criteria: 1. The target disease has cerebral metastasis; 2. The medical history and complications, which may affect patients' ability to participate in the study and their safety during the study, or interfere with explanation of the study results, for example: severe cardiovascular and cerebrovascular diseases, uncontrolled diabetes, uncontrolled hypertension, uncontrolled infection, active peptic ulcer, etc.; 3. Dementia, altered mental state, or any mental illness that prevents understanding or informed consent or questionnaires; 4. History of allergy or hypersensitivity to any therapeutic ingredient; 5. Combined with other malignant tumors excepted pancreatic cancer within the first 5 years of admission, excepted cured basal cell or squamous cell carcinoma of the skin, local prostate cancer after radical surgery, ductal carcinoma in situ after radical surgery; 6. Subjects with peripheral neuropathy ≥2 according to CTCAE version 5.0; 7. Physical examination or laboratory examination results are abnormal; 1. Hematological dysfunction is defined as: i) absolute neutrophil (ANC) count \<1.5 × 109 / L; ii) platelet (PLT) count: \<100 × 109 / L; iii) hemoglobin (Hb) level\<90g / L; 2. Hepatic abnormalities are defined as: i) total bilirubin (TBil) levels: \>1.5 times the upper limit of normal (ULN); ii) aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels \>2.5 times the ULN \>5 times ULN if liver metastases are present; 3. Definition of renal dysfunction: serum creatinine \>1.5 times ULN, or calculated creatinine clearance \<50ml / min; 4. Definition of abnormal blood coagulation function: International Normalized Ratio (INR) \>1.5 times of ULN, and prothrombin time (PT) or activated partial thromboplastin time (aPTT) \>1.5 times of ULN, unless the subject is receiving anti-antibodies Coagulation treatment. 8. Hepatitis B surface antigen positive (HBsAg), and subjects with peripheral blood hepatitis B virus DNA (HBV-DNA) titer ≥1×103 copies / L; if HBsAg is positive, and peripheral blood HBV-DNA \<1×103 copy number / L, if the researcher believes that the subject's chronic hepatitis B is in a stable phase and does not increase the risk of the subject, the subject is eligible for selection; 9. Hepatitis C virus (HCV) or human immunodeficiency virus (HIV) positive; 10. Patients who need to combine other anti-tumor drugs; 11. Participation in any trial drug treatment or another interventional clinical trial 30 days before screening period. 12. Other conditions that researchers not think to be suitable for enrollment.