Background: Unresectable pancreatic cancer (PC) is associated with fatal outcomes despite chemotherapy and radiation. PD-1 antibodies might provide favorable long-term survival in combination with chemotherapy according to previous clinical trials and pilot studies. In this study, we conducted a real-world evaluation of PD-1 antibody in old patients with unresectable PC. We also aimed to explore biomarkers for the early prediction of PD-1 antibodies response. Methods: This is a single-arm, single-center, real-world study. Primary Objectives: ORR. Secondary Objectives: DCR, OS, PFS, Safety(CTCAE). Exploratory Objectives: The alteration of molecular biomarkers to PD-1 antibodies treatment including IL-2, IL-4, IL-10, IL-16, TNF¦Á and IFN-¦Ã, ect. Key eligibility criteria: Histopathologically confirmed advanced unresectable PC; Without systematic treatment; ¡Ý60 years old; ECOG PS 0 or 1; Evaluated by mRECIST PD-1 plus AG, Q3W Surgery Until disease progression, unacceptable toxicity, or up to 2 years. Results: From Jan 2021 to Dec 2021, 10 unresectable PC patients were enrolled in Yuhang campus, the first affiliated hospital, Zhejiang university school of medicine, which their baseline characteristics were listed in Table. A total of 9 patients were finally included and analyzed. Clinical decisions were made by multi-disciplinary team. The treatment efficacy was evaluated by mRECIST. A total of 9 patients were assessable for response. ORR was 33.3%, with 3/9 partial response (PR). 5/9 patients were stable disease (SD), and DCR was 88.9%. Conversion therapy uses rational immunotherapy and chemotherapy and so on combined with MDT assessment to translate initial unresectable case to resectable one, which obviously prolongs survival time and improves quality of life. For patients with surgically unresectable PC 2 patients were successfully transformed. The rate of overall surgical conversions was 22.2%. The most common adverse events were anemia (6 [60%] patients). There were no treatment-related level 4 and 5 adverse events. There was no treatment-related cardiotoxicity. No patients were interrupted due to adverse events. Conclusions: PD-1 antibody plus Chemotherapy demonstrates significant clinical activity and favorable tolerability in old patients with advanced unresectable PC, and DCR was 88.9%.

ECOG PS, Eastern Cooperative Oncology Group Performance Status; HBV+: Hepatitis B Virus Infection; HCV+: Hepatitis C Virus Infection.