Failure signal comparison
Efficacy vs safety clinical trial failure signals
Efficacy/futility and safety are the two buckets closest to biological clinical trial failure signals. They are useful together, but they do not mean the same thing.
- The dataset contains 1,097 efficacy/futility records and 718 safety records.
- Efficacy/futility records are mostly terminated trials, with 1,044 terminated records.
- Safety records include 634 terminated, 64 withdrawn, and 20 suspended records.
- Oncology is the largest efficacy/futility disease area with 304 records; Oncology is the largest safety disease area with 277 records.
- Phase II is the largest efficacy/futility phase group, while Phase II is the largest safety phase group.
The short version
If I had to separate clinical trial failure signals into two practical groups, I would start here: efficacy/futility and safety. They are both closer to biological risk than an operational or unclear stop reason.
But they are not interchangeable. An efficacy or futility stop usually asks whether the treatment worked well enough. A safety stop asks whether the risk profile made continuing hard to justify.
Why this distinction matters
A trial can stop because the drug did not show enough benefit, because adverse events changed the risk-benefit picture, or because the registry language points to tolerability problems. Those are different analytical stories.
For research, investing, competitive intelligence, or target evaluation, that difference matters. Calling everything a failed clinical trial hides the most useful part of the evidence: what kind of failure signal appeared.
What the dataset shows
In the current stopped-trial dataset, efficacy/futility signals are larger than safety signals: 1,097 efficacy/futility records versus 718 safety records. That does not make safety less important. It means the two should be reviewed side by side, not collapsed into one vague failure bucket.
Most records in both groups are terminated trials: 1,044 efficacy/futility records and 634 safety records. Still, withdrawn and suspended records appear in both buckets, which is another reminder that trial status alone is not enough. The stop reason is doing the real work.
How I would use this
For a fast screen, I would first filter to efficacy/futility when I care about weak activity, endpoint failure, lack of benefit, or futility language. Then I would filter to safety when I care about adverse events, toxicity, tolerability, or risk signals.
After that, I would read the source language. The classification is a starting point for analysis, not a substitute for the ClinicalTrials.gov record.
Signal counts by stop-reason type
| Signal type | Records |
|---|---|
| Efficacy/futility | 1,097 |
| Safety | 718 |
Status mix inside each signal
| Status | Records |
|---|---|
| Efficacy/futility terminated | 1,044 |
| Efficacy/futility withdrawn | 34 |
| Efficacy/futility suspended | 19 |
| Safety terminated | 634 |
| Safety withdrawn | 64 |
| Safety suspended | 20 |
Top disease areas
| Disease area | Records |
|---|---|
| Efficacy/futility: Oncology | 304 |
| Efficacy/futility: Other | 258 |
| Efficacy/futility: Neurology | 92 |
| Efficacy/futility: Gastroenterology & Hepatology | 88 |
| Efficacy/futility: Infectious Disease | 86 |
| Safety: Oncology | 277 |
| Safety: Other | 128 |
| Safety: Infectious Disease | 58 |
| Safety: Gastroenterology & Hepatology | 52 |
| Safety: Cardiovascular | 34 |
Phase mix
| Phase | Records |
|---|---|
| Efficacy/futility: Phase II | 480 |
| Efficacy/futility: Phase III | 313 |
| Efficacy/futility: Phase I | 93 |
| Efficacy/futility: Phase I + Phase II | 80 |
| Safety: Phase II | 258 |
| Safety: Phase I | 161 |
| Safety: Phase III | 124 |
| Safety: Phase I + Phase II | 96 |
Continue from here
FAQ
Are efficacy/futility and safety both clinical trial failure signals?
Yes, they can both be useful biological failure signals, but they point to different questions: whether the intervention worked well enough, and whether the risk profile was acceptable.
Is a safety stop worse than an efficacy stop?
Not automatically. The interpretation depends on the intervention, patient population, disease severity, dose, alternatives, and exact source language.
Should I count all terminated trials as efficacy failures?
No. Terminated status only says the study stopped early. The stop reason is needed before calling it an efficacy, safety, operational, or unclear signal.
Source note: counts are generated from the current ClinicalTrials.gov-derived stopped-trial dataset used by ClinicalTrialFailures.com. These labels are analytical screening signals, not medical advice.