Quantitative evaluation of single-arm versus randomized phase II cancer clinical trials
Bibliographic record
Abstract
BACKGROUND: There is a debate among cancer researchers about the use of single-arm or randomized phase II clinical trial designs; however, there is limited published objective evaluation of this issue. PURPOSE: To objectively quantify the impact on phase III clinical trials of a policy of all single-arm versus all randomized phase II trials. METHODS: A simulation study was performed comparing optimal single-arm and randomized phase II trial designs with a variety of commonly used α and β error rates. Parameters modeled included: between-institution variability in the standard of care response rate, between-institution variability in the treatment effect, between-institution variability in the estimate of historical control rate (for selecting H0), presence of historical bias, and proportion of phase II trials conducted using active agents. RESULTS: Using single-arm phase II trials resulted in a higher percentage of phase III trials conducted using active agents when there was minimal standard of care activity, or in the presence of a positive historical bias (H0 estimated to be greater than truth). Randomized phase II trials performed better in the presence of a negative historical bias, in the presence of high variability, and were more consistent across variation of historical bias. The proportion of phase III trials conducted using active agents was increased by reducing the α error. Presence of historical bias and the proportion of active agents studied in phase II had the greatest influence on results. LIMITATIONS: It was estimated that between 5% and 20% of agents studied in phase II trials are active; however, the conclusions could change if this estimate is incorrect. This study did not account for the possibility of a new drug application submission immediately following phase II. The primary outcome looked at was response rate, although some investigators have suggested that time-to-event outcomes should be used in phase II, particularly for randomized phase II trials. CONCLUSIONS: Both single-arm and randomized phase II trials appear warranted in certain situations. Investigators should increase consideration of the potential impact on phase III trials to optimally select the proper trial design prior to phase II study implementation.
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 | 0.639 | 0.829 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.007 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.001 | 0.006 |
| Scholarly communication | 0.006 | 0.005 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".