Pancreas Ductal Adenocarcinoma

The purpose of this study is to find the highest dose of a drug, samuraciclib, that can be given with standard of care chemotherapy (gemcitabine and nab-paclitaxel) without causing very severe side effects. This is done by starting at a dose lower than the one that is used when samuraciclib is taken by itself without chemotherapy. The main question it aims to answer is: • For patients with newly diagnosed metastatic pancreatic cancer, what is the safety and tolerability of samuraciclib with gemcitabine/nab-paclitaxel? Participants will: * Undergo a tumor biopsy. * Be treated with samuraciclib in combination with their standard of care chemotherapy (gemcitabine/nab-paclitaxel). * Donate research blood samples.