A phase I/II study combining tosedostat with capecitabine in patients with metastatic pancreatic adenocarcinoma.

Abstract

TPS471 Background: Metastatic pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. Recent advances with fluorouracil in combination with oxaliplatin and irinotecan (FOLFIRINOX) and nab-paclitaxel combined with gemcitabine (AG) have improved survival in patients with PDAC. A fluorouracil-based regimen is recommended for patients who progress after a gemcitabine-based regimen. Tosedostat is an oral aminopeptidase inhibitor shown to have anti-proliferative effects in malignancies. Aminopeptidase inhibitors disrupt the cleavage of amino acids from peptides downstream of proteasomal degradation, preventing the recycling of amino acids needed for new protein synthesis. This leads to intracellular depletion of amino acids, resulting in a cellular stress response known as the amino acid deprivation response, which leads to apoptosis. Because pancreatic cancer cells frequently upregulate expression of these aminopeptidases, aminopeptidases inhibitors hold therapeutic promise. Methods: This is a single institution phase I/II open-label trial to evaluate the safety and tolerability of tosedostat plus capecitabine in patients with metastatic PDAC that have progressed after a gemcitabine-based regimen. The phase I part will be conducted in a dose de-escalation fashion, with two planned dose levels of tosedostat (120mg or 60mg) p.o. daily on days 1 to 21 with capecitabine 1000 mg/m2 p.o. BID on days 1 to 14 of a 21-day cycle. If more than one patient in the tosedostat (120 mg) cohort experiences a dose limiting toxicity (DLT), then 6 more patient will be enrolled to the tosedostat (60 mg) cohort. A total of 36 patients will be enrolled in the phase II portion. Primary objective of the phase I portion is to determine the maximum tolerated dose and DLTs of tosedostat and capecitabine combination therapy. Primary objective of the phase II portion is to determine the progression-free survival at 3 months. Secondary objectives are to determine the overall response rate, time-to-progression, overall survival and CA 19-9 response. Exploratory objectives are to explore the predictive molecular biomarkers for treatment response and to explore the prognostic biomarkers. Clinical trial: NCT02352831. Clinical trial information: NCT02352831.