Objective: nab-Paclitaxel has been shown to disrupt pancreatic cancer stroma and was effective in combination with gemcitabine in a phase I/II trial. This study was designed to determine the efficacy of nab-paclitaxel monotherapy in previously treated pancreatic cancer patients.
Methods: In this phase II trial, patients with advanced pancreatic cancer who progressed on gemcitabine-based therapy, received nab-paclitaxel 100 mg/m over 30 minutes on days 1, 8, and 15 of a 28-day cycle. The primary endpoint was 6-month overall survival (OS). Secondary endpoints were response rate (by Response Evaluation Criteria In Solid Tumors), progression-free survival, safety, and toxicity profile.
Results: Among 19 patients treated, the median age was 61 years, 9 (47%) were male patients and 18 (95%) had stage-IV disease. The primary endpoint of the study was reached with a 6-month OS of 58% [95% confidence interval (95% CI), 33%-76%] and an estimated median OS of 7.3 months (95% CI, 2.8-15.8 mo). The median progression-free survival was 1.7 months (95% CI, 1.5-3.5 mo). One patient had a confirmed partial response and 6 (32%) had stable disease as their best response. Nonhematological toxicities were generally mild with grades 1-2 nausea, anorexia, hypocalcemia, and vomiting occurring in 63%, 47%, 37%, and 26% of patients, respectively. Grades 3-4 neutropenia, neutropenic fever, and anemia occurred in 32%, 11%, and 11% of patients, respectively. Only 2 of 15 available tumors stained positive for secreted protein acid rich in cysteine, and neither of these patients benefited from the therapy.
Conclusions: nab-Paclitaxel was well tolerated, and it demonstrated preliminary evidence of activity in a subset of patients who progressed on gemcitabine-based therapy.