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
PANAMA was a randomized phase 2, parallel-group, open-label treatment trial in metastatic colorectal cancer evaluating maintenance chemotherapy with or without panitumumab.
| Feature | PANAMA |
|---|---|
| Condition | Metastatic Colorectal Cancer |
| Design | Randomized, parallel assignment, no masking |
| Primary purpose | Treatment |
| Lead sponsor | AIO-Studien-gGmbH |
| Interventions | Maintenance chemotherapy; panitumumab during maintenance; mFOLFOX6 and panitumumab during re-induction |
2. Clinical Question
Population
Patients with metastatic colorectal cancer enrolled in a maintenance therapy comparison after prior induction and re-induction treatment.
Intervention
5-FU/FA plus panitumumab during maintenance therapy.
Comparator
5-FU/FA alone during maintenance therapy.
Primary question
Does maintenance therapy with panitumumab affect progression-free survival during maintenance therapy?
3. Trial Design
Randomization
The registry describes the study as randomized with parallel assignment.
Masking
No masking was used.
Allocation
Two treatment arms were included.
Study period
Start date: 2014-04. Primary completion date: 2023-02-18.
4. Trial Arms
Maintenance chemotherapy plus panitumumab
5-FU/FA plus panitumumab during maintenance therapy.
Maintenance chemotherapy alone
5-FU/FA alone during maintenance therapy.
5. Primary Endpoint
| Endpoint | Definition | Time frame |
|---|---|---|
| Progression-free survival | Time from randomization until disease progression or death, whatever occurs first, during maintenance therapy. | Until end of follow-up (24 months after randomization) |
6. Planned Analysis
The registry identifies progression-free survival as the primary endpoint but does not report posted statistical analyses or numerical efficacy results on ClinicalTrials.gov.
For a randomized maintenance therapy trial with a progression-free survival endpoint, the usual statistical framework evaluates time from randomization to progression or death using methods such as Kaplan-Meier estimation, treatment-group comparisons, and model-based hazard estimates. The registry does not report the formal analysis results for this endpoint.
7. Statistical Methodology
Progression-free survival analysis
Progression-free survival is a time-to-event endpoint. Patients contribute follow-up time from randomization until progression, death, or the last assessment if the event has not occurred. This structure requires methods that account for censoring.
The Kaplan-Meier estimator is commonly used to describe event-free survival over time. A hazard ratio model may be used to compare relative event rates between randomized groups when appropriate.
Randomization and interpretation
Randomization creates the basis for comparing treatment groups because treatment assignment is determined by the study design rather than patient characteristics. The interpretation of any treatment effect depends on the prespecified analysis framework and the quality of follow-up data.
8. Statistical Methods Explained
Why is progression-free survival a time-to-event endpoint?
Progression-free survival measures time until one of two events occurs: disease progression or death. Patients without an event at the analysis time are censored rather than treated as having failed.
Why does censoring matter?
Censoring allows patients with incomplete event information to contribute available follow-up without assuming that their outcome is known.
Why is randomization important?
Randomization helps balance known and unknown prognostic factors between groups, supporting a causal comparison of assigned treatments.
What does an open-label design mean statistically?
No masking means investigators and participants know assigned treatment. Objective endpoints may reduce some bias concerns, but endpoint assessment and follow-up procedures remain important.
9. Limitations
- The registry does not report posted statistical analyses or numerical efficacy estimates.
- No subgroup results, safety results, or detailed analysis populations are reported in the registry record.
- Open-label treatment assignment can influence aspects of care or assessment.
- Time-to-event endpoints depend on follow-up duration and handling of censored observations.
10. Why This Trial Matters Statistically
| Concept | How it appears in PANAMA |
|---|---|
| Randomized comparison | Maintenance strategies are compared using randomized treatment assignment. |
| Time-to-event analysis | Progression-free survival is defined as the primary endpoint. |
| Censoring | Patients without progression or death by the end of observation require survival-analysis methods. |
| Maintenance strategy evaluation | The design separates effects of maintenance treatment after prior therapy. |