Results of a Randomized, Double-Blind, Placebo-Controlled, Phase 1b/2 Trial of Nabpaclitaxel + Gemcitabine ± Olaratumab in Treatment-Naïve Participants with Metastatic Pancreatic Cancer.

Simple Summary: Nabpaclitaxel plus gemcitabine is the standard of care treatment for advanced pancreatic ductal adenocarcinoma (PDAC), the third leading cause of cancer-related deaths worldwide. This therapy reported improved overall survival in metastatic PDAC. Despite the efficacy of available treatments, the poor outcome for patients with PDAC necessitates the need for novel therapies. In a preclinical study, a neutralizing monoclonal antibody specific to human platelet-derived growth factor receptor alpha (PDGFRα) has proven its efficacy in advanced PDAC. Further, a PDGFRα monoclonal antibody, olaratumab, in combination with chemotherapy demonstrated clinical benefit in patients with soft tissue sarcoma. In light of the above findings, the current trial evaluates the efficacy and safety of olaratumab and nabpaclitaxel plus gemcitabine combination therapy in treatment-naïve patients with metastatic PDAC. However, the combination therapy failed to improve survival outcomes compared with chemotherapy alone. Nevertheless, the safety profile of olaratumab was consistent with the previous studies. The efficacy and safety of olaratumab plus nabpaclitaxel and gemcitabine in treatment-naïve participants with metastatic pancreatic ductal adenocarcinoma was evaluated. An initial phase 1b dose-escalation trial was conducted to determine the olaratumab dose for the phase 2 trial, a randomized, double-blind, placebo-controlled trial to compare overall survival (OS) in the olaratumab arm vs. placebo arms. In phase 1b, 22 participants received olaratumab at doses of 15 and 20 mg/kg with a fixed dose of nabpaclitaxel and gemcitabine. In phase 2, 159 participants were randomized to receive olaratumab 20 mg/kg in cycle 1 followed by 15 mg/kg in the subsequent cycles (n = 81) or the placebo (n = 78) on days 1, 8, and 15 of a 28-day cycle, plus nabpaclitaxel and gemcitabine. The primary objective of the trial was not met, with a median OS of 9.1 vs. 10.8 months (hazard ratio [HR] = 1.05; 95% confidence interval [CI]: 0.728, 1.527; p = 0.79) and the median progression-free survival (PFS) was 5.5 vs. 6.4 months (HR = 1.19; 95% CI: 0.806, 1.764; p = 0.38), in the olaratumab vs. placebo arms, respectively. The most common treatment-emergent adverse event of any grade across both arms was fatigue. Olaratumab plus chemotherapy failed to improve the OS or PFS in participants with metastatic PDAC. There were no new safety signals. [ABSTRACT FROM AUTHOR]