Background: Metastatic pancreatic cancer is a leading cause of cancer death worldwide with limited treatment options. Durvalumab, the anti- PD-L1 inhibitor has revealed remarkable efficacy in solid malignancies including hepatobiliary cancers. We conducted a study to evaluate the efficacy and safety of a combination therapy of Durvalumab, Albumin paclitaxel and Lenvatinib (ALLEN Regimen) in patients with mPC. Methods: This open-label, single-center, single-arm, phase Ⅱ clinical trial investigated patients with metastatic pancreatic cancer. Durvalumab (1000mg IV, q3w), albumin paclitaxel(180-220 mg/m² IV q3w) and lenvatinib (8mg PO QD) were given regularly until disease progression. The primary endpoint was objective response rate (ORR) evaluated by investigators according to RECIST 1.1. The secondary endpoints were disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and treatment-related adverse events (TRAEs). Results: Between September 2021 and September 2023, seventeen patients with ECOG score 0-2 were enrolled, including 8 patients (47%) who were refractory to at least one systemic chemotherapy.The median follow-up was 6.0 months (95% CI 4.0, 8.4). 17 patients were evaluable, with a median age of 58 years. 9 patients (52.9%) were male. The ORR and DCR were 64.7% and 94.1%, respectively. The median PFS was 7.8 months (95% CI 3.1, 11.4), and the median OS was 8.1 months (95% CI 4.7, 13.5). TRAEs (all grades) occurred in 16 (94.1%) patients. The most common grade 1-2 TRAEs were nausea 8 (47.1%), diarrhoea 5(29.4%), peripheral sensory neuropathy 3 (17. 6% ) and hypertension 3(17.6% ). No grade 3 or higher TRAEs occurred. Conclusions: The ALLEN regimen demonstrated promising antitumor activity and well acceptable toxicity in metastatic pancreatic cancer. Further randomized controlled studies will be required in a larger patient population. Clinical trial information: NCT05327582.