# Interim analysis, readout and data cut-off

Source: https://onco.cc/terms/interim-analysis/  
OnCo record `interim-analysis` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A trial's results are not one event but a series: pre-planned looks at the data (interim analyses) while it is still running, a data cut-off date that freezes the dataset for each look, a 'topline' announcement of the headline numbers, and a final analysis when enough events have happened.

## Summary

Time-to-event trials are 'event-driven': analyses occur after a set number of progressions or deaths, so timing depends on how fast events accrue, and companies announce 'readouts' when those milestones arrive. Interim analyses use alpha-spending so that repeated looks do not inflate false positives; a positive interim for progression-free survival often comes years before the final overall survival analysis. Topline press releases precede peer-reviewed publication by months and may omit key details, which is why the site distinguishes press-release from published evidence. The data cut-off, not the publication date, is the date the numbers describe.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: interim analysis; interim analyses; first interim analysis; second interim analysis; prespecified interim; final analysis; final OS analysis; primary analysis; data cut-off; data cutoff; data cut; readout; read out; reads out; topline; top-line; topline results; top-line data; headline results; updated analysis; long-term follow-up; extended follow-up; 5-year update; results expected; data expected

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Interim_analysis
- Wikipedia: https://en.wikipedia.org/wiki/Interim_analysis

## Connected records

- terms: [Data maturity (immature vs mature survival data)](https://onco.cc/terms/data-maturity/), [Data monitoring committee (DSMB, IDMC)](https://onco.cc/terms/data-monitoring-committee/), [Futility analysis (stopped for futility)](https://onco.cc/terms/futility/), [Group sequential design, stopping rules and alpha spending](https://onco.cc/terms/group-sequential-design/), [Landmark and milestone survival (5-year survival, median follow-up)](https://onco.cc/terms/landmark-survival/), [Master protocol (platform, basket and umbrella trials)](https://onco.cc/terms/master-protocol/), [Primary, secondary and co-primary endpoints](https://onco.cc/terms/primary-endpoint/), [Seamless, adaptive and Bayesian trial designs](https://onco.cc/terms/seamless-adaptive/), [Statistical power, sample size and re-estimation](https://onco.cc/terms/sample-size-re-estimation/), [Statistical significance (P values, alpha, multiplicity)](https://onco.cc/terms/statistical-significance/), [Trial lifecycle: from protocol to label](https://onco.cc/terms/trial-lifecycle/)
- fronts: [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/)
- trials: [ADAURA](https://onco.cc/trials/adaura/), [FOCUS4](https://onco.cc/trials/focus4/), [GBM AGILE](https://onco.cc/trials/gbm-agile/), [Precision Promise](https://onco.cc/trials/precision-promise/), [STAMPEDE](https://onco.cc/trials/stampede/), [TrilynX](https://onco.cc/trials/trilynx/)
- journals: [Leukemia](https://onco.cc/journals/leukemia/)

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JSON: https://onco.cc/api/v1/entities/interim-analysis.json