Sequence Dependence of MEK Inhibitor AZD6244 Combined with Gemcitabine for the Treatment of Biliary Cancer
Bibliographic record
Abstract
PURPOSE: MEK inhibition has clinical activity against biliary cancers and might therefore be successfully combined with gemcitabine, one of the most active chemotherapy agents for these cancers. As gemcitabine is active in S-phase, and the extracellular signal-regulated kinase (ERK) pathway has a major role driving cell-cycle progression, concurrent use of a MEK inhibitor could potentially antagonize the effect of gemcitabine. We therefore tested the sequence dependence of the combination of gemcitabine and the MEK inhibitor AZD6244 using a series of biliary cancer models. EXPERIMENTAL DESIGN: Primary xenografts were established from patients with gallbladder and distal bile duct cancer and grown in severe combined immunodeficient (SCID) mice at the subcutaneous site. Plasma and tumor drug levels and the time course for recovery of ERK signaling and S-phase were measured in tumor-bearing mice treated for 48 hours with AZD6244 and then monitored for 48 hours off treatment. On the basis of these results, two different treatment schedules combining AZD6244 with gemcitabine were tested in four different biliary cancer models. RESULTS: DNA synthesis was suppressed during treatment with AZD6244, and reentry into S-phase was delayed by approximately 48 hours after treatment. Strong schedule dependence was seen in all four biliary cancer models tested, suggesting that combined treatment with AZD6244 plus gemcitabine would be more active in patients with biliary cancer when gemcitabine is given following a 48-hour interruption in AZD6244 dosing, rather than concurrently. CONCLUSIONS: The combination of AZD6244 plus gemcitabine is highly schedule dependent, and predicted to be more effective in the clinic using sequential rather than simultaneous dosing protocols.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".