The purpose of this study is to look at the efficacy and safety of HR070803 in combination with 5 fluorouracil/leucovorin (5FU/LV) plus oxaliplatin compared to nab-paclitaxel + gemcitabine treatment in improving the overall survival of patients not previously treated for metastatic pancreatic cancer.

Inclusion Criteria:

1. ECOG performance status 0 or 1
2. Histological or cytologically confirmed pancreatic cancer that has not been previously treated in the metastatic disease.
3. Life expectancy of greater than or equal to3 months.
4. At least one measurable lesion is present according to the efficacy evaluation criteria for pancreatic cancer (RECIST 1.1)
5. Able and willing to provide a written informed consent

Exclusion Criteria:

1. Patients with pancreatic cancer originating from extrapancreatic ductal epithelium, including pancreatic neuroendocrine carcinoma, acinar cell carcinoma of the pancreas, pancreatoblastoma, and solid-pseudopapillary tumor;
2. Known history of central nervous system (CNS) metastases.
3. Severe infection (> CTCAE grade 2), such as severe pneumonia, bacteremia, infection complications, etc. requiring inpatient treatment, occurred within four weeks before enrollment, and symptoms and signs of infection requiring intravenous antibiotic therapy (except for prophylactic antibiotics) occurred within two weeks before enrollment;
4. Patients with cardiac clinical symptoms or diseases that are not well controlled, such as: (1) Patients with NYHA class 2 and above cardiac failure; (2) unstable angina; (3) myocardial infarction that occurred within 6 months; (4) clinically significant supraventricular or ventricular arrhythmia requiring treatment or intervention.