Penpulimab combined with anlotinib and nab-paclitaxel plus gemcitabine (PAAG) as first-line treatment for metastatic pancreatic cancer: A prospective, multicenter, single-arm, phase 2 study.

4135 Background: Chemotherapy currently serves as the cornerstone for treating metastatic pancreatic cancer (mPC). Nevertheless, the survival of patients with mPC remains poor. Besides, the efficacy of single-agent immune checkpoint inhibitors or antiangiogenesis in the treatment of mPC is not satisfying. Therefore, it is important to explore combination therapy options for patients with mPC. This trial was conducted to evaluate the effectiveness and safety of penpulimab combined with anlotinib and nab-paclitaxel plus gemcitabine (PAAG) for mPC. Methods: This was a prospective, multicenter, single-arm phase II trial. Eligible pts were those who aged over 18 years, histologically or cytologically confirmed PC, have not received treatment before and radiographically showed distant metastases and measurable lesions. Patients received penpulimab (200mg, IV, D1) and Anlotinib (12mg, P.O, QD, D1-14), in addition to nab-paclitaxel (125mg/m 2 , I.V, D1,8) and gemcitabine (1.0g/m 2 , I.V, D1,8), administered over a 21-day treatment cycle. The primary endpoint was objective response rate (ORR) and disease control rate (DCR). Secondary end points included Progression-free Survival (PFS), overall survival (OS) and safety. Immune microenvironmental features of baseline were analyzed as exploratory results (NCT05493995). Results: 66 pts were enrolled and received PAAG therapy, and the last follow-up time was December 31, 2023. All pts were eligible for response evaluation. The ORR was recorded at 50% (33/66) (95% CI, 37.4%-62.6%), with 33 pts achieving partial response. The DCR was 95.5% (63/66) (95% CI, 87.3%-99.1%). With median follow-up duration of 12.8 months, median PFS was 8.8 months (95% CI, 8.1–11.3) and median OS was 13.7 months (95% CI, 12.4-not reached). The most common TRAEs were anaemia, leukocytopenia, fatigue and rash. Grade 3 TRAEs were reported in 36.4% pts (24/66). In exploratory analysis, higher T cell recruiting score and lower baseline serum CA72-4 level were detected in PR pts compared with SD/PD pts. Furthermore, the B cell, NK CD56dim cell and Th9 cell scores were up-regulated in PFS-long pts. Conclusions: PAAG regimen as first-line treatment was demonstrated to be tolerable, with promising anti-tumor activity in mPC. The identified biomolecular markers revealed potential to guide precision treatment of PAAG for mPC. Clinical trial information: NCT05493995 .