Weiss GJ, et al. - Researchers conducted a single center phase Ib/II study of gemcitabine, nab-paclitaxel, and pembrolizumab (GNP) to assess the safety and efficacy in metastatic pancreatic adenocarcinoma (PDAC) was conducted (NCT02331251). As per findings, chemotherapy naïve PDAC patients could receive GNP safely. Compared to previously reported results, efficacy seemed slightly improved for standard weekly × 3 every 28 day gemcitabine and nab-paclitaxel dosing. For overall survival (OS), copy number instability (CNI) change could be prognostic.

Methods

• Until progression or toxicity, GNP was administered to PDAC patients (pts) with measurable disease, biopsy proven metastasis, adequate laboratory tests, and KPS ≥ 70%.
• Researchers conducted safety monitoring, RECIST 1.1, and immune-related response criteria assessments(irRECIST).
• They performed response imaging prior to cycle 4, then every 3 months.
• A retrospective evaluation of changes in tumor cell-free DNA copy number instability (CNI) was performed.

Results

• A total of 17 pts were treated; median age was 56 years, 11 were women.
• All had a KPS of at least 80%.
• Researchers observed grade 3 events in 53% of patients.
• For chemotherapy naïve PDAC pts, the phase II portion was completed.
• The disease control rate (partial response [PR] + stable disease[SD]) was 100% among the 11 evaluable chemotherapy naïve PDAC.
• They observed 3 with PR on treatment for 8+, ~11, and 15 months; respectively.
• The study did not met the primary endpoint of >15% complete response.
• For chemotherapy naïve treated patients, the median progression-free survival (PFS) and overall survival (OS) were 9.1 and 15.0 months.
• A greater reduction in CNI correlated with longer PFS and improved OS among 9 patients evaluable for CNI change.