• Object response rate (ORR) [ Time Frame: 24 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
• 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.

• 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.
• 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.

• 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.
• 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 the first 3-week cycle, and then inhaled 0.4mg/kg twice in the first week of each 3-week cycle thereafter
• Drug: nab-paclitaxel
  Administered intravenously, 180-220mg/m2 on day 2 in a 3-week cycle (day 1 without Manganese priming)
  Other Name: Paclitaxel For Injection (Albumin Bound)
• Drug: Platinum chemotherapy
  Administered intravenously, Cisplatin (60-80mg/m2) or Carboplatin (area under the curve [AUC] 4-6 mg/mL per min) on day 2 in a 3-week cycle (day 1 without Manganese priming)
• Drug: Sintilimab
  Administered intravenously, 200mg on day 3 in a 3-week cycle (day 2 without Manganese priming)
  Other Name: anti-PD-1 antibody; PD-1 inhibitor

• Experimental: Manganese primed Sintilimab plus nPP chemotherapy
  Subject received Manganese primed Sintilimab, nab-paclitaxel and platinum chemotherapy every 3 weeks until achieving a second assessable complete response or progressive disease, development of unacceptable toxicity, or withdrawal of consent.
  Interventions:

  • Drug: Manganese Chloride
  • Drug: nab-paclitaxel
  • Drug: Platinum chemotherapy
  • Drug: Sintilimab
• Active Comparator: Sintilimab plus nPP chemotherapy
  Subject received Sintilimab, nab-paclitaxel and platinum chemotherapy every 3 weeks until achieving a second assessable complete response or progressive disease, development of unacceptable toxicity, or withdrawal of consent.
  Interventions:

  • Drug: nab-paclitaxel
  • Drug: Platinum chemotherapy
  • Drug: Sintilimab

Inclusion Criteria:

1. Subjects must have histologically proven relapsed or refractory ovarian cancer (Refractory was defined as a lack of response to or progression during the frontline treatment; relapsed was defined as progression after the frontline treatment), including patients diagnosed with primary carcinoma of fallopian tube or peritoneum carcinoma.
2. Female.
3. ≥ 18 years old.
4. Life expectancy of at least 6 months.
5. Eastern Cooperative Oncology Group performance status 0-2.
6. Radiographic imaging (CT/MRI/PET-CT) indicated recurrence or metastasis; or cancer cells in ascites are positive; or CA125 concentration in the peripheral blood is more than 2 times the upper limit of normal value.
7. Subjects must have received at least two frontline therapies, at least one of which is platinum-containing.
8. Subjects with Anti-PD-1 antibody treatment history are eligible which must be resistance.
9. Adequate organ function.
10. Female 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.
7. Subjects with previous or concurrent other malignancies.