Background: Cytotoxic chemotherapy remains the preferred first-line treatment for advanced or unresectable pancreatic cancer with combination regimens including 5-fluoruracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX), or gem and nab-p. The use and response of second- and third-line therapies remains dismal, thus the optimization of first-line treatment is critical. Our previous work investigating Gln metabolism in pancreatic ductal adenocarcinoma (PDAC) through glutaminase inhibition indicates that Gln deprivation in PDAC increases cancer cell survival and resistance to chemotherapy. However, when PDAC cell were treated with Gln supplementation, there was an increase in PDAC cell death with increasing concentrations of gem. In this present study we aim to test the feasibility and safety of combining L-Gln with gem and nab-p in treatment-naïve patients with unresectable or metastatic PDAC. Methods: This is a single arm, single center, phase I study. The primary objective is to assess the recommended phase II dose (RP2D) of L-Gln in combination with gem and nab-p. The RP2D will be assessed by escalation of overdose control (EWOC), an adaptive Bayesian design, through determination of the maximum tolerated dose (MTD) across 3 doses of gem, nab-p, and L-Gln. The MTD is defined as the dose such that the probability of dose-limiting toxicities (DLTs) at the MTD is θ = 0.33. The first patient will receive 1000 mg/m² gem, 125 mg/m² nab-p, and 0.1 g/kg L-Gln and the subsequent doses will be determined by the EWOC algorithm. We plan to enroll a maximum of 16 patients. L-Gln is administered orally BID throughout the 28-day cycle with a one-week lead-in prior to the beginning of the first cycle where gem and nab-p are administered on days 1, 8, and 15 of each cycle. Key inclusion criteria include: advanced or unresectable, histologically confirmed pancreatic cancer that is either new or recurrent (if recurrent, prior neoadjuvant or adjuvant chemotherapy or chemoradiation is allowed but must have been completed >12 months prior to recurrence), ECOG PS ≤ 2 or KP ≥ 60%, and normal organ and marrow function. Secondary objectives are to describe any preliminary evidence of antitumor activity by assessment of objective response rate, progression-free survival, and overall survival. Since October 2020, 3 patients have been screened and 3 enrolled. Clinical trial information: NCT04634539.