• Number of Subjects with treatment-related adverse events (AEs) [ Time Frame: 12 months ]
  Incidence, nature, and severity of adverse events graded according to the NCI CTCAE v5.0. AEs were considered to be treatment-related if they had started or worsened within the interval from first study drug administration until the follow-up visit.
• Disease control rate (DCR) [ Time Frame: 12 months ]
  DCR is defined as the proportion of subjects who achieved a stable disease (SD), partial response (PR) or complete response (CR) according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

• Object response rate (ORR) [ Time Frame: 12 months ]
  ORR is defined as the proportion of subjects who achieved a partial response (PR) or complete response (CR) according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.
• Progression-free survival (PFS) [ Time Frame: 12 months ]
  PFS time was measured from study entry to the first documentation of disease progression or death. Disease progression was determined per the RECIST V1.1.
• Overall survival (OS) [ Time Frame: 24 months ]
  OS time was measured from the study entry to the date of death.
• Number of participants with laboratory test abnormalities [ Time Frame: 12 months ]
  The laboratory tests of serum cytokines and chemokines will be performed on day 1 and 3 of each cycle, and the abnormality will be determined by the investigator.

• Drug: Manganese Chloride
  Administered by inhalation at 0.4mg/kg twice per week in a 3-week cycle
• Drug: nab-paclitaxel
  Administered intravenously, 200mg/d on day 1 and day 8 in a 3-week cycle
  Other Name: Paclitaxel For Injection (Albumin Bound)
• Drug: Gemcitabine
  Administered intravenously, 1g/m2/d on day1 and day8 in a 3-week cycle
• Drug: anti-PD-1 antibody
  Administered intravenously, 2-4mg/kg on day 2 in a 3-week cycle
  Other Name: Anti-PD-1 monoclonal antibody; PD-1 inhibitor

• Experimental: Manganese primed anti-PD-1 antibody plus nPG chemotherapy
  Subject received Manganese primed anti-PD-1 antibody, nab-paclitaxel and gemcitabine every 3 weeks until achieving a second assessable stable disease or up to a maximum of 12 cycles. Treatment continued until progressive disease, development of unacceptable toxicity, or withdrawal of consent.
  Interventions:

  • Drug: Manganese Chloride
  • Drug: nab-paclitaxel
  • Drug: Gemcitabine
  • Drug: anti-PD-1 antibody
• Experimental: anti-PD-1 antibody plus nPG chemotherapy
  Subject received anti-PD-1 antibody, nab-paclitaxel and gemcitabine every 3 weeks until achieving a second assessable stable disease or up to a maximum of 12 cycles. Treatment continued until progressive disease, development of unacceptable toxicity, or withdrawal of consent.
  Interventions:

  • Drug: nab-paclitaxel
  • Drug: Gemcitabine
  • Drug: anti-PD-1 antibody

Inclusion Criteria:

1. Subjects must have histologically proven local advanced/metastatic pancreatic cancer
2. ≥ 18 years old.
3. Life expectancy of at least 6 months.
4. Eastern Cooperative Oncology Group performance status 0-2.
5. Subjects must have at least one measurable lesion ≥ 1 cm as defined by response criteria.
6. Subjects with Anti-PD-1 antibody treatment history are eligible which must be resistance.
7. Adequate organ function.
8. Participants of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 120 days after the last dose of study drug.

Exclusion Criteria:

1. Subjects with any autoimmune disease or history of syndrome that requires corticosteroids or immunosuppressive medications.
2. Serious uncontrolled medical disorders or active infections, pulmonary infection especially.
3. Prior organ allograft.
4. Women who are pregnant or breastfeeding.
5. Women with a positive pregnancy test on enrollment or prior to investigational product administration.
6. Subjects who are compulsorily detained for treatment of either a psychiatric or physical (eg, infectious disease) illness.