People with primary metastatic pancreatic cancer will be treated with nab-paclitaxel and gemcitabine in combination with an investigational agent called M402. It is made from heparin, which is a well known blood thinner. Blood thinners have been shown in prior animal and human studies to have anti-cancer effects. M402 has been re-engineered from heparin to have much lower blood thinning activity while keeping the anti-tumor activity. The investigators are testing whether M402 administered in combination with nab-paclitaxel and gemcitabine may be more effective than nab-paclitaxel and gemcitabine.