This was a prospective observational study. Patients with histologically or radiologically confirmed MPP and fail to other systemic therapy were enrolled. Penpulimab will be administered intravenously at a dose of 200 mg every 3 weeks. Treatment continued until the patient exhibited radiographic or clinical disease progression or unacceptable adverse events.Plasma normetanephrine and metanephrine (MNs), 24-hour urinary catecholamine excretion (24hCA) were measured at baseline and every 1-3cycle. Contrast-enhanced computed tomography(CT) of chest, abdomen and pelvis were used to assess measurable target lesions at baseline and every 3 cycles. For patients who only had bone metastases or no measurable target lesions, The efficacy was evaluated by 18F-fluorodeoxyglucose (18F-FDG-PET/CT). The primary endpoint was objective response rate (ORR) and the disease control rate (DCR) per Response Evaluation Criteria In Solid Tumors(RECIST) 1.1/PERCIST1.0. Secondary endpoints included biochemical (catecholamine levels) response rate (BRR), progression-free survival (PFS) and safety.
Metastatic pheochromocytoma / paraganglioma (MPP) are rare while the prognosis was poor. Penpulimab is specifically an immune check-point inhibitor of PD1 and has been approved for the treatment of several malignancies.This phase II trial studies the efficacy and safety of penpulimab in the treatment of MPP patients who fail to other systemic therapy.