This study is designed determine progression free survival (PFS) of nab-paclitaxel administered in combination with gemcitabine at two different dose combinations in patients with unresectable stage IIIB/stage IV non-squamous non-small cell lung cancer (NSCLC). Two dosing strategies of the nab-paclitaxel plus gemcitabine combination will be compared for efficacy and tolerability. One arm will combine both agents at their current Food and Drug Administration (FDA) approved doses for the indication of non-small cell lung cancer (NSCLC). This arm will utilize gemcitabine 1250 mg/m2 IV day 1 and day 8 (FDA approved dose in combination with cisplatin) combined with nab-paclitaxel 100 mg/m2 IV day 1, 8 and 15 every 21 days (FDA approved dose in combination with carboplatin). The second arm will utilize the drugs at doses that are approved by the FDA when combined with one another in metastatic pancreatic adenocarcinoma. This arm will consist of gemcitabine 1000 mg/m2 IV day 1, 8 and 15 combined with nab-paclitaxel at 125 mg/m2 IV day 1, 8 and 15 every 28 days. Patients will be randomized equally to the two treatment arms. Primary objective is to assess progression-free survival (PFS). Toxicity assessment, response and overall survival are secondary endpoints. Statistical power is based on the comparison to historical control within each treatment arm. In particular, a sample size of 23 patients in each arm will have 84% power to differentiate the 3-month PFS of 30% (null hypothesis) versus 60% (alternative) based on a 2-sided test at a significance level of 0.05. There will be a lead-in phase to this trial for each treatment arm with a cohort size of 3 and a maximum of 6 patients.