- What was tested: oral L-glutamine (30 g per day) added to gemcitabine and nab-paclitaxel (GA) in 16 people with untreated advanced pancreatic ductal adenocarcinoma (PDAC) [1].
- Main result: the planned dose was reached. The three dose-limiting toxicities were attributed to the chemotherapy, not to glutamine [1].
- Early signals, not proof: tumors shrank in 15 of 16 participants and median overall survival was 22 months. With no control group, these numbers cannot show that glutamine helps [1].
- Next step: a randomized trial, according to the authors [1].
Why this matters
Advanced pancreatic ductal adenocarcinoma has a poor prognosis: the trial’s authors cite a 5-year survival of 3% for stage IV (metastatic) disease [1]. A foundation of treatment for metastatic disease is chemotherapy that includes gemcitabine, commonly combined with nab-paclitaxel (GA) [1].
Glutamine adds a puzzle. Some pancreatic tumors can depend on glutamine for growth and survival, and disrupting glutamine uptake and metabolism has been reported to make PDAC cells more sensitive to chemotherapy. Those effects were short-lived, however, because backup pathways appear to compensate [1]. This trial tried the opposite approach: giving extra glutamine by mouth. The authors point to preclinical studies in which glutamine supplementation had antitumor activity, through a mechanism that is not yet understood [1]. For background on why some cancer cells depend on glutamine, see our earlier post.
The study
Researchers at Cedars-Sinai Medical Center in Los Angeles enrolled 16 adults with advanced PDAC between May 2021 and June 2023. Fifteen had metastatic disease and one had locally advanced or unresectable disease. None had yet received first-line treatment for metastatic disease [1].
Every participant first took oral L-glutamine alone for one week, then continued it alongside standard gemcitabine and nab-paclitaxel. Doses were adjusted with a Bayesian dose-finding design. The glutamine was a clinical-grade formulation already approved by the US Food and Drug Administration (FDA) for sickle cell disease [1].
The trial was open-label, single-arm and nonrandomized: all participants received the same treatment, and there was no comparison group. At the start, 81% met consensus criteria for cachexia, a wasting syndrome [1].
What the researchers found
| Measure | Result |
|---|---|
| Recommended phase 2 dose (primary endpoint) | Reached at the maximum planned doses: 30 g of glutamine per day with full standard doses of GA |
| Dose-limiting toxicities | 3, all attributed to GA rather than glutamine |
| Grade 3 or higher treatment-related adverse events | 66.7%, mainly from the chemotherapy |
| Tumor shrinkage | 15 of 16 participants (94%) |
| Best overall response | 44% (2 complete and 5 partial responses); 8 had stable disease and 1 had progression |
| Median progression-free survival | 8.5 months (95% CI 6 to not reached) |
| Median overall survival | 22 months (95% CI 11 to not reached); 69% alive at 12 months and 40% at 24 months |
| Follow-up | Median 20 months; 5 participants alive at the data cutoff in May 2024 |
Exploratory laboratory analyses showed that blood glutamine levels rose after supplementation. Overall gut microbiome composition did not change, although some bacterial metabolic pathways did. Blood levels of lipopolysaccharide (LPS), a bacterial product, fell, which the authors interpret as better gut barrier function. They describe these findings as hypothesis-generating [1].
Dose finding used an extended escalation with overdose control (EWOC) Bayesian design with a target dose-limiting toxicity probability of 0.33. The 30 g per day ceiling reflects the FDA-recommended upper limit and the low solubility of oral glutamine (3.6% at 23 °C). In the exploratory analyses, “long” survival was defined as exceeding historical medians for GA alone (PFS 167 days, OS 258 days). The authors note that this outcome-informed stratification needs validation in a larger study [1].
What this does not show
- No control group. The authors compare their results with historical figures from a pivotal phase 3 trial of GA alone. Comparisons across different trials and populations are unreliable. The authors state that their results do not support the claim that glutamine plus GA is better than GA alone [1].
- Small and single-center. Phase 1 trials are designed to find a safe dose, not to test effectiveness [1].
- Immature survival data. Five participants were still alive at the data cutoff, so the survival figures may change [1].
- Chemotherapy toxicity remained. About two-thirds of participants had a grade 3 or higher treatment-related adverse event, mainly from the chemotherapy [1].
- Other combinations are untested. The safety and efficacy of glutamine with other drugs in PDAC remain unknown [1].
What happens next
The authors say the central question, whether adding glutamine improves on GA alone, needs a randomized first-line trial. They also note that treatment for advanced PDAC is changing, with RAS inhibitors entering first-line testing alongside GA [1]. A short commentary in the same issue of Nature Cancer addresses the same topic [2].
- Paper
- Gong J, Muranaka H, Choi SY, et al. Nature Cancer 7(9):1406–1418, 2026. doi:10.1038/s43018-026-01225-z
- Peer review
- Published in a peer-reviewed journal; the paper lists a peer review file.
- Registration
- ClinicalTrials.gov NCT04634539
- Full text
- Free on PubMed Central
- Funding and interests
- Listed in the paper’s declarations.
This post summarizes a published study for general information. It is not medical advice. People with cancer should discuss any supplement with their oncology team before taking it.
References
- J. Gong et al., “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,” Nat. Cancer, vol. 7, no. 9, pp. 1406–1418, Sep. 2026 (published online Aug. 31, 2026). doi: 10.1038/s43018-026-01225-z. PMID: 42675216. Full text: PMC13600916.
- “L-Glutamine’s potential to enhance chemotherapy efficacy in advanced pancreatic cancer,” Nat. Cancer, vol. 7, no. 9, pp. 1328–1329, Sep. 2026. doi: 10.1038/s43018-026-01231-1. PMID: 42680940.
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Department of Molecular Diagnostics, Faculty of Biomedical Sciences, University of Benghazi, Libya
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