Phase Ib/II study combining tosedostat with capecitabine in patients with advanced pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with limited therapeutic options. We evaluated the safety and efficacy of the aminopeptidase inhibitor tosedostat with capecitabine in advanced PDAC.

We conducted a phase Ib/II trial of tosedostat with capecitabine as second-line therapy for advanced PDAC. Planned enrollment was 36 patients. Eligible patients were treated with capecitabine 1,000 mg/m² oral twice-daily days 1-14 and oral tosedostat in a dose de-escalation design on days 1-21 of each 21-day cycle. Primary endpoints were the recommended phase 2 dose (RP2D) and progression-free survival (PFS).

Sixteen patients were enrolled. Tosedostat 120 mg oral twice daily with capecitabine 1,000 mg/m² oral twice daily was the RP2D. There was one dose-limiting toxicity (DLT) (grade 3 acute coronary syndrome) during phase Ib. The most common treatment-related adverse events were gastrointestinal (nausea, diarrhea), cardiac [QTc prolongation, decreased ejection fraction (EF)], and fatigue. The median PFS was 7.1 months, and the median treatment failure free survival was 3 months. Eight patients experienced stable disease for greater than 3 months. The study was closed early due to lack of drug availability.

Tosedostat with capecitabine displayed tolerable toxicity, and prolonged disease control in a subset of patients. These data encourage further exploration of aminopeptidase inhibitors in pancreatic cancer.