This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
NOA-04 was a randomized phase 3 study of sequential radiochemotherapy of anaplastic glioma with PCV or temozolomide-based treatment strategies.
| Feature | NOA-04 |
|---|---|
| Condition | Anaplastic Astrocytoma; Oligodendroglioma; Oligoastrocytoma |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None |
| Primary purpose | Treatment |
| Lead sponsor | Neuro-Oncology Working Group of the German Cancer Society |
2. Clinical Question
Population
Patients with anaplastic astrocytoma, oligodendroglioma, or oligoastrocytoma.
Intervention
Sequential radiochemotherapy strategies involving chemotherapy and focal radiotherapy.
Comparator
The randomized parallel treatment strategy assigned in the study.
Primary question
The study evaluated time-to-treatment-failure after radiotherapy and one chemotherapy sequence.
3. Trial Design
Randomization
The study used randomized allocation.
Study structure
The design model was parallel with two treatment arms and no masking.
Study period
Enrollment began in 1999-06 and primary completion occurred in 2005-02.
Enrollment
A total of 318 participants were enrolled.
4. Endpoints
| Endpoint | Definition | Time frame |
|---|---|---|
| Time-to-treatment-failure | Defined as progression after radiotherapy and one chemotherapy in either sequence | 1999-2008 |
5. Planned Analysis
The ClinicalTrials.gov record identifies the primary endpoint as a time-to-event outcome. Time-to-treatment-failure endpoints are typically analyzed using methods that account for follow-up time, censoring, and the timing of failure events.
6. Statistical Methodology
Time-to-event analysis
Time-to-treatment-failure compares how long participants remain without the defined failure event. Unlike simple proportions, time-to-event methods incorporate when events occur and allow participants without an observed event at the end of follow-up to contribute partial information.
The choice of analysis method depends on the prespecified statistical analysis plan and the characteristics of the observed event data.
Censoring
Participants who have not experienced treatment failure by the end of observation are typically censored rather than treated as if failure occurred. Proper handling of censoring is essential for unbiased time-to-event estimation.
7. Statistical Methods Explained
Why is time-to-treatment-failure a time-to-event endpoint?
Because the endpoint measures the time until a defined event occurs, the analysis must incorporate both event occurrence and follow-up duration.
Why does randomization matter?
Randomization creates treatment groups that can be compared without relying on measured baseline differences alone.
Why is censoring important?
A participant who has not experienced failure at the end of follow-up still provides information about the period during which failure did not occur.
Why are registry endpoint definitions important?
Precise endpoint definitions determine which events count, when measurement begins, and how statistical comparisons should be interpreted.
8. Limitations
- The ClinicalTrials.gov record does not report posted statistical analyses or endpoint estimates.
- Detailed event counts, confidence intervals, p-values, subgroup analyses, and safety comparisons are not reported in the registry record.
- Interpretation of a time-to-event endpoint depends on the prespecified analysis plan and observed follow-up data.
9. Why This Trial Matters Statistically
| Concept | How it appears in NOA-04 |
|---|---|
| Randomization | Participants were assigned using randomized allocation. |
| Parallel design | The trial used a parallel study structure with two arms. |
| Time-to-event analysis | The primary endpoint was time-to-treatment-failure. |
| Endpoint definition | The registry specifies failure after radiotherapy and one chemotherapy sequence. |
10. Related Tutorials
Learn more about the methods used in this trial: