Background: The performance of immune checkpoint inhibitor (ICI) monotherapy was proved to be disappointing in pancreatic ductal adenocarcinoma (PDAC). Increasing evidence has shown the promising efficacy of ICIs combined with systemic therapy in the first-line treatment in solid tumors.

Case presentation: We reported a case of a metastatic PDAC patient who had a long-term partial response and good tolerance to the combined approach of toripalimab (a novel PD-1 inhibitor) and gemcitabine plus nab-paclitaxel (GA). PD-L1 positive expression was detected in his liver metastases. Besides, we described a phenomenon of pseudo-progression of this patient during the course of therapy.

Conclusion: As the first-line treatment of metastatic PDAC patients, GA plus toripalimab may provide a novel combined approach with favorable response and manageable toxicity. Further clinical trials are needed to confirm the results. Pseudo-progression requires special attention and to be differentiated with true progression in patients undergoing immunotherapy.

背景：事实证明，免疫检查点抑制剂（ICI）单一疗法在胰腺导管腺癌（PDAC）中令人失望。越来越多的证据表明，在实体瘤的一线治疗中，ICI与全身治疗相结合的疗效令人鼓舞。

案例介绍：我们报道了一例转移性PDAC患者，该患者具有长期的部分应答，并且对toripalimab（一种新型PD-1抑制剂）和吉西他滨加nab-紫杉醇（GA）的联合治疗方法具有良好的耐受性。在他的肝转移中检测到PD-L1阳性表达。此外，我们描述了该患者在治疗过程中的伪进展现象。

结论：作为转移性PDAC患者的一线治疗，GA加toripalimab可能提供一种新颖的联合治疗方法，具有良好的疗效和可控的毒性。需要进一步的临床试验以确认结果。伪进展需要特别注意，并在接受免疫治疗的患者中与真正进展区分开。