Plasma arginine as a candidate predictive biomarker for response to immune checkpoint inhibition (ICI) in metastatic colorectal cancer (mCRC): Analysis of the CCTG CO.26 trial.
Bibliographic record
Abstract
3545 Background: Nutritional stress is one of the mechanisms used by tumour cells to evade the immune system. Arginine (ARG), an amino acid involved in several cellular functions including immunomodulation, is important in regulating T-lymphocyte cell activity and the anti-tumour response. ARG deficiency in the tumour microenvironment has been shown to impair T-cell response while ARG supplementation may promote anti-tumour immune activity. In this exploratory post-hoc analysis of the Phase II CO.26 trial (NCT02870920), we investigated the role of plasma ARG in predicting response to ICI in patients (pts) with refractory mCRC. Methods: CO.26 was a phase II trial which randomized pts with refractory mCRC to durvalumab plus tremelimumab (D+T) versus best supportive care (BSC). Plasma ARG concentrations were determined from blood samples pre-treatment using HPLC-tandem mass spectrometry. The median plasma ARG value was used as a cut-off stratifying pts into ARG-high (≥10650 ng/ml) versus ARG-low ( < 10650 ng/ml) groups. Progression-free (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared between groups using the log-rank test. Cox proportional hazard models were used to analyze prognostic and predictive impacts of ARG on PFS and OS. Results: Of 180 pts enrolled in CO.26, 162 pts (N = 115 treated with D+T and 47 BSC) had pre-treatment blood samples for baseline ARG analysis. There were no significant differences in baseline characteristics between pts included in this analysis and the total study pts, or between ARG-high and ARG-low pts. In pts treated with D+T, ARG-high was associated with more favourable prognosis (ARG-high median OS 7.62 months vs. ARG-low 5.49 months, multivariable hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.40-0.91, p = 0.016). In ARG-high pts, D+T significantly improved OS (median OS 7.62 months with D+T vs 3.61 months BSC; HR 0.61, 95% CI 0.37-0.99, p = 0.04). In ARG-low pts there was no OS benefit with D+T (median OS 5.49 months D+T vs 4.27 months BSC; HR 0.84, 95% CI 0.50-1.41, p = 0.51. Interaction p = 0.037). Baseline ARG values had no association with PFS or disease control rate. Conclusions: Baseline plasma ARG was prognostic in pts with mCRC treated with D+T, and high ARG was predictive of improved OS with ICI. Prospective studies should be done to validate ARG as a biomarker identifying mCRC pts likely to derive benefit from ICI. Therapeutic approaches targeting the ARG pathway should be investigated in future studies.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".