Increased Preclinical Efficacy of Irinotecan and Floxuridine Coencapsulated Inside Liposomes Is Associated With Tumor Delivery of Synergistic Drug Ratios
Bibliographic record
Abstract
Whether anticancer drug combinations act synergistically or antagonistically often depends on the ratio of the agents being combined. We show here that combinations of irinotecan and floxuridine exhibit drug ratio-dependent cytotoxicity in a broad panel of tumor cell lines in vitro where a 1:1 molar ratio consistently provided synergy and avoided antagonism. In vivo delivery of irinotecan and floxuridine coencapsulated inside liposomes at the synergistic 1:1 molar ratio (referred to as CPX-1) lead to greatly enhanced efficacy compared to the two drugs administered as a saline-based cocktail in a number of human xenograft and murine tumor models. When compared to liposomal irinotecan or liposomal floxuridine, the therapeutic activity of CPX-1 in vivo was not only superior to the individual liposomal agents, but the extent of tumor growth inhibition was greater than that predicted for combining the activities of the individual agents. In contrast, liposome delivery of irinotecan:floxuridine ratios shown to be antagonistic in vitro provided antitumor activity that was actually less than that achieved with liposomal irinotecan alone, indicative of in vivo antagonism. Synergistic antitumor activity observed for CPX-1 was associated with maintenance of the 1:1 irinotecan:floxuridine molar ratio in plasma and tumor tissue over 16-24 h. In contrast, injection of the drugs combined in saline resulted in irinotecan:floxuridine ratios that changed 10-fold within 1 h in plasma and sevenfold within 4 h in tumor tissue. These results indicate that substantial improvements in the efficacy of drug combinations may be achieved by maintaining in vitro-identified synergistic drug ratios after systemic administration using drug delivery vehicles.
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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 | 0.003 | 0.001 |
| 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 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".