Analyzing the efficacy and safety of immunotherapy in pancreatic ductal adenocarcinoma (PDA): A systematic review and meta-analysis.

Abstract

512 Background: The tumor microenvironment in PDA is heterogeneous and immunosuppressive given the presence of regulatory T cells and exhausted effector T cells. Despite the upsurge of effective immunotherapeutic agents (IA) in other tumor types, the role in PDA remains unknown. We conducted a meta-analysis of IA in PDA. Methods: Following PRISMA guidelines, we searched PubMed/MEDLINE, Elsevier/Embase, Wiley/Cochrane Library and ClinicalTrials.gov. Articles were selected per the following criteria: (1) Study participants had a diagnosis of PDA; (2) An IA was used in the trial. Titles, abstracts and full text articles were reviewed by 2 independent reviewers; disagreements were resolved by a third. Data extraction and analysis were performed by 3 independent reviewers. Descriptive analysis, mean, median, confidence interval and forest plots were used for statistical analysis. Results: We found 20,792 studies through the database, 16,105 remained after duplicates were removed and 15,889 were excluded due to irrelevance. Strict inclusion criteria were applied to the full text of 216 articles. The most common reason for exclusion were conference abstracts (44%) and ongoing trials (16%). Fifty-four trials (39 metastatic (met), 12 adjuvant (Ad) and 3 neoadjuvant (nAd) met criteria for further analysis. Age range was 27-86 (median 61) and 52.3% were males. IA included cytokine therapy (33%), peptide vaccines (22%), dendritic cell vaccine (13%), oncolytic viruses (9%), CTLA-4 inhibitors (2%) and others. IA in met-PDA had a median overall survival (mOS) of 8.1 months (ms) and a disease control rate (DCR) of 55.4% (95% CI, 51.85-58.95). There was no statistical difference in DCR among IA subtypes (range 49-60%) (p = 0.22). The mOS of Ad-PDA trials was 25 ms (historically comparable to gemcitabine, p = 0.75) and 18 ms for nAd-PDA. The most common Gr1/2 toxicities were skin reactions, fever, and chills and Gr3/4 were cytopenias, diarrhea, and mucositis. One death occurred due to neutropenic sepsis. Conclusions: IA demonstrates modest efficacy in the treatment of met-PDA albeit exhibits a favorable toxicity profile. Many trial results are available only in abstract format and some are ongoing.