The Efficacy and Safety of Penpulimab in the Treatment of Metastatic PPGL Patients Who Fail to Other Systemic Treatment

Inclusion Criteria:

* Provide written informed consent.
* Age 18-75 years old
* Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2.
* Patients with histologically or radiologically confirmed MPP and fail to other systemic therapy.
* Estimated life expectancy longer than 6 months.
* Confirmed non-pregnancy and lactation. During the entire study period and within 6 months after the last administration, the subjects and their spouses are willing to use efficient contraceptive measures.
* Laboratory requirements:

  * Absolute granulocyte count (AGC) greater than 1.5 x 109/L;
  * Platelet count greater than 80 x 109/L;
  * Hemoglobin greater than 90g/L;
  * Serum bilirubin less than 1.5 x upper limit of normal (ULN);

    --)Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) less than 2.5 x ULN;
  * Serum creatinine less than 1.5 x ULN or creatinine clearance (CCr)≥60ml/min;
  * Doppler ultrasound assessment: left ventricular ejection fraction (LVEF) ≥ lower limit of normal value (50%).

Exclusion Criteria:

* Patients who had been previously treated with anti-PD1, anti-PD-L1, or anti-PD-L2 medications were excluded from this trial.
* Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days prior to the first dose of trial treatment.
* Has a known history of active TB (Bacillus Tuberculosis).
* Has a known history of Human Immunodeficiency Virus (HIV).
* Has known active Hepatitis B (e.g., HBsAg reactive) or Hepatitis C (e.g., HCV RNA \[qualitative\] is detected).
* Has an active infection requiring systemic therapy.
* Didn't meet eligibility for organ function.
* Abnormal coagulation (INR \>1.5 or prothrombin time (PT) \> ULN 4 seconds or APTT \>1.5 ULN), bleeding tendency or being treated with thrombolytic or anticoagulant therapy.
* Uncontrolled congestive heart failure .