L-Glutamine in Combination with First-Line Gemcitabine and Nab-Paclitaxel in Advanced Pancreatic Ductal Adenocarcinoma: an Open-Label, Single-Arm, Phase 1 GlutaPanc Trial

Exogenous L-glutamine has preclinical antitumor activity although formal clinical translation has not been attempted. We conducted a single-arm phase 1 trial to assess the safety and preliminary efficacy of clinical-grade, US Food and Drug Administration-approved L-glutamine therapy with gemcitabine and nab-paclitaxel (GA) in participants with treatment-naive, advanced pancreatic cancer (n = 16). The primary endpoint was to determine the recommended phase 2 dose (RP2D) by adaptive Bayesian design across standard doses of GA and a dose range of 0.1-0.3 g kg-1 twice-daily oral L-glutamine. Secondary endpoints included safety and preliminary efficacy of the study combination. The primary endpoint was met with the RP2D reached at maximum doses of L-glutamine and GA. The grade ≥3 treatment-related adverse event rate was 66.7%, primarily from GA. Addition of L-glutamine to GA induced tumor shrinkage in 94% of subjects with a best overall response rate (ORR) of 44% (12.5% complete response). Median progression-free survival and overall survival (OS) were 8.5 months (95% confidence interval (CI) 6-not reached (NR)) and 22 months (95% CI 11-NR), respectively. L-Glutamine induced distinct metagenomic and metabolomic signatures on exploratory analyses in glutamine-treated subjects as a single agent, while the combination of L-glutamine and GA nearly doubled the ORR and tripled the OS compared to historical GA alone (ClinicalTrials.gov registration: NCT04634539 ).