Hedgehog Inhibitors for Metastatic Adenocarcinoma of the Pancreas

The emergence of new small molecules with capacity of blocking the Hedgehog signaling pathway provides a novel therapeutic approach in pancreatic adenocarcinoma treating the primary tumor, stroma, systemic metastases and pancreatic cancer stem cells by hedgehog pathway inhibition. This phase 2 clinical trial will evaluate the progression free survival (PFS) in patients with previously untreated metastatic pancreatic adenocarcinoma. We hypothesize that the combination of cytotoxic agents (gemcitabine and nab-paclitaxel) with the Hedgehog inhibitor GDC-0449 may increase PFS. This study includes correlative studies to attempt to understand the stem cell biology and mechanism for any observed clinical benefits with the use of Hedgehog inhibitor GDC-0449. These include changes in the hedgehog pathway and changes in pancreatic cancer stem cell markers with pre and post treatment biopsies. The safety of GDC-0449 when combined with chemotherapy gemcitabine and nab-paclitaxel will also be assessed by evaluating adverse event rate. Following the determination of eligibility patients will receive the following treatment: 1. One cycle of Gemcitabine 1000 mg/m2 and nab-Paclitaxel 125 mg/m2 on days 1, 8, and 15 (28 days cycle) then 2. Gemcitabine 1000 mg/m2 and nab-Paclitaxel 125 mg/m2 on days 1, 8, and 15 every 28 days cycle in combination with oral GDC-0449 150 mg daily Patients may continue on treatment regimen until they experience progressive disease or unacceptable toxicity, require palliative radiotherapy, withdraw consent or the physician feels it is not longer in their best interest to continue on treatment.