This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety Extension Study Of Tanezumab When Administered By Subcutaneous Injection To Patients With Osteoarthritis (NCT01127893), a randomized phase 3 study. The primary outcome is Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01127893 |
| Phase | Phase 3 |
| Condition | Osteoarthritis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
People with osteoarthritis of the knee were the intended study population. The registry lists an enrollment of 1, and describes the analysis population as randomized participants who received at least 1 dose of study medication. The study was terminated prematurely, so the posted safety follow-up covers baseline to early termination rather than the intended long-term period.
Intervention
The intervention was subcutaneous tanezumab, intended to be administered every 8 weeks for up to 64 weeks. The registry lists tanezumab dose groups of 2.5 mg, 5 mg, and 10 mg. The posted adverse-event figures include a group titled Tanezumab 2.5 mg.
Comparator
A comparator is not identified in the available arm descriptions. Those descriptions are blank, and the posted adverse-event figures contain only the Tanezumab 2.5 mg group. A comparison between tanezumab and another treatment cannot therefore be described from these figures.
Primary question
The primary endpoint asks how many participants had adverse events or serious adverse events from baseline to early termination, specified as Day 107. It is a safety question, not a measure of treatment benefit. The registry record says the study ended prematurely because of a US FDA-imposed clinical hold and that all planned analyses were not performed.
3. Trial Design
This was a Phase 3, randomized, double-masked, parallel-group study of subcutaneous tanezumab in patients with osteoarthritis of the knee. The stated purpose was long-term safety evaluation, with administration intended every 8 weeks for up to 64 weeks. The registry lists three tanezumab dose groups: 2.5 mg, 5 mg, and 10 mg. The arm descriptions themselves are blank, and no comparator is identified in those descriptions.
The registry records enrollment of 1. That entry is a registry figure, not evidence that the intended study completed its planned recruitment or follow-up. The record states that a US FDA-imposed clinical hold led to premature termination. The primary endpoint's timeframe is baseline up to early termination, identified as Day 107. The primary population description says that it included randomized participants who received at least 1 dose of study medication; it also says that not all planned analyses were performed. The population description is truncated in the record, so any further details are not reported in the registry record.
The listed secondary outcomes cover WOMAC pain, physical function, and stiffness; Patient Global Assessment; OMERACT-OARSI response; and specified levels of pain reduction. These outcomes were scheduled at multiple follow-up points, including Week 4 through Week 64 for several measures. Their presence in the registry describes planned outcome measures, not completed results. The registry lists 22 outcome measures but reports 0 analyses. Thus, the design provides context for what investigators intended to assess, while the posted results do not supply a completed long-term or comparative evaluation.
The record gives a start date of 2010-06-15 and a primary completion date of 2010-09-29. The study status is TERMINATED. The dates and status should be read alongside the explicit statement that the trial ended early; they do not establish that participants completed the planned follow-up.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Due to the United States Food and Drug Administration (US FDA) imposed clinical hold, the study was terminated prematurely. Only 1 participant was enrolled and treated with tanezumab 2.5 mg treatment group and other planned treatments, tanezumab 5 or 10 mg, were not administered.
Overall Study
| Stage | Tanezumab 2.5 mg |
|---|---|
| STARTED | 1 |
| COMPLETED | 0 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Tanezumab 2.5 mg |
|---|---|
| Study Termination by the Sponsor | 1 |
Analysis population for the primary outcome, as defined in the registry: ITT analysis population included all randomized participants who received at least 1 dose of study medication. Due to the US FDA imposed clinical hold, the study was terminated prematurely. Consequently, all planned analyses were not performed; data reported here is for baseline up to early termination (Day 107).
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: Intent to treat (ITT) analysis population included all randomized participants who received at least 1 dose of study medication.
| Characteristic | Unit | Tanezumab 2.5 mg |
|---|---|---|
| Participants analysed | 1 | |
| Age, Continuous | years | 63 |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs), measured over Baseline up to Early Termination (Day 107).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with adverse events (AEs) and serious adverse events (SAEs). Its timeframe is baseline up to early termination, identified as Day 107. An AE is defined broadly as an untoward medical occurrence in a participant administered a product or medical device; it does not need to be caused by the treatment. An SAE is an AE resulting in outcomes such as death, initial or prolonged inpatient hospitalization, a life-threatening experience, persistent or significant disability or incapacity, or congenital anomaly, or otherwise considered significant.
The registry defines treatment-emergent events as those occurring between the first dose and early termination that were absent before treatment in this study or worsened relative to the pretreatment state. This distinction matters because a safety count may include events that are not judged to have been caused by the study drug. It describes what occurred during the observation period, not necessarily what the intervention caused.
Counting participants with an event is a useful safety summary because it indicates how many people experienced an event under the endpoint definition. It is different from counting every event: a participant may experience more than one event, but the endpoint is expressed in participants. The count does not by itself show how long events lasted, how severe non-serious events were, or whether an event was treatment-related. The early termination also limits the endpoint's observation window relative to the intended period of up to 64 weeks. The registry record does not provide a completed comparative analysis of this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted adverse-event figures are limited to the Tanezumab 2.5 mg group. They report 1 participant at risk for the serious-event category and 0 with a serious event; the other-event fields also report 1 at risk and 0 with an event. The death field is not populated, so deaths are not reported in the registry record. No top serious-event terms are listed. These figures describe the entries in this group, rather than a comparison across the listed dose groups.
A zero count in the posted figures means that no event was recorded for that category among the participant count shown. It does not establish that the underlying risk is zero, nor does it show what would have occurred with longer observation. The registry states that the study was terminated prematurely and that the intended safety evaluation was for up to 64 weeks. The primary endpoint data cover baseline to early termination, Day 107. The shortfall between intended and actual observation is especially important for a long-term safety question: events that might occur later cannot be assessed from a truncated follow-up period.
The record lists enrollment of 1, but the posted adverse-event group also shows 1 at risk. Neither entry supports a reliable estimate of comparative event frequency across treatment groups. The other listed dose groups do not have corresponding figures in the adverse-event results described in the registry record. A dose-response pattern, a contrast with another treatment, and an adjusted treatment effect are therefore not available.
The registry lists 22 outcome measures and 0 analyses. It explicitly says all planned analyses were not performed because the study was terminated after a US FDA-imposed clinical hold. No confidence interval, hypothesis test, or model-based estimate is reported in the registry record for the primary endpoint. Without those analyses, the posted counts cannot establish the precision of an estimated event frequency or support an inferential comparison. The absence of an analysis is not evidence that groups were equivalent.
Interpretation should remain descriptive. The posted numbers show the recorded safety counts in the one displayed group and the limited number of participants at risk. They do not establish a comprehensive safety profile for tanezumab, characterize uncommon events, or resolve how risks might differ by dose. Nor do the planned secondary outcomes establish findings: listed outcomes without reported analyses are plans or registry entries, not observed results. The early termination, sparse group figures, absent comparator information, and missing analysis results all constrain what can be concluded.
9. Statistical Methods Explained
What does a participant count describe?
The primary outcome is a count of participants with AEs and SAEs. A participant count answers whether people experienced at least one qualifying event in the specified observation period; it is not the total number of events. This distinction is useful because one person can experience more than one event. The registry's endpoint wording focuses on participants, so the posted counts should be understood as people with events rather than a tally of event episodes.
Safety event definitions also determine what enters a count. The AE definition is broad and does not require a causal relationship with treatment. The SAE definition uses specified serious consequences or a judgment that an event is significant for another reason. Treatment-emergent events are further restricted to events between first dose and early termination that were absent before treatment in this study or worsened relative to the pretreatment state. These definitions help describe the endpoint, but they do not prove that treatment caused an event.
What do randomization and masking contribute?
Randomization is intended, in general, to reduce systematic differences between assigned groups by using an allocation process rather than investigator choice. Double masking is intended, in general, to limit the influence of treatment knowledge on participant experience, care, and outcome assessment. A parallel-group design assigns participants to a group and follows those groups over time, rather than having every participant receive each intervention in sequence. These are general design concepts; the registry record does not report implementation details beyond identifying the study as randomized, double masked, and parallel.
Those design features do not substitute for results. The available adverse-event figures include only the Tanezumab 2.5 mg group. No group-to-group estimate is posted for the primary endpoint, and a design label alone cannot show whether groups had different outcomes. The arm descriptions are blank, and a comparator is not identified in them. Details about allocation procedures, masking procedures, or a statistical analysis plan are not reported in the registry record.
Why is the analysis population important?
The stated ITT analysis population included all randomized participants who received at least 1 dose of study medication. This definition determines which people are included in the analysis population; it is not the same as a result. The record indicates that the study ended early and that all planned analyses were not performed. The population description is truncated, so additional rules for handling participants or observations are not reported in the registry record.
General statistical interpretation depends on knowing both who was included and how incomplete follow-up was handled. If outcome information is unavailable for some participants, the method for addressing that missingness can affect estimates. The registry does not report a missing-data method for the primary endpoint. Since early termination curtailed the intended follow-up, the absence of later measurements is a substantive limitation, not merely a technical detail that can be assumed away.
How should precision and inference be understood?
A confidence interval is, in general, a range of values that expresses uncertainty around an estimated effect or event frequency under a specified statistical procedure. A narrow interval is generally more precise than a wide interval, while sparse data can leave substantial uncertainty. No confidence interval or inferential estimate for the primary endpoint is reported in the registry record. The displayed count should therefore not be mistaken for a precise estimate of the underlying risk.
Hypothesis tests and model-based analyses can assess evidence for differences under stated assumptions. They require a defined comparison and an analysis method. The registry lists 0 analyses, and the posted primary endpoint results do not supply a comparative estimate or test. No p-value or adjusted estimate is reported in the registry record. It is not possible to infer statistical significance, equivalence, or a lack of difference from a zero count in the available group.
For binary outcomes such as whether a participant experienced an event, analyses may compare the number of people with and without the event across groups. In general, sparse counts can make such estimates unstable and imprecise. A zero observed count does not mean the probability of an event is zero; it means none was recorded in the observed data for that category. With only the posted group information, no meaningful between-group comparison can be reconstructed.
What can the planned sample-size illustration say?
Sample-size calculations are planning tools, not evidence about outcomes. The stated illustration uses the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it describes the effect to detect as a stated fraction of the observed effect. The general purpose of such an illustration is to show how a hypothetical design might relate sample size to a target effect and specified assumptions. It is not observed power, and it is not the trial's own design justification. The registry record does not report the trial's sample-size justification.
The primary endpoint has fewer than two arms in the posted results, so the available record does not support a comparative planning illustration for that endpoint. The registry also does not report a completed observed effect estimate on which to base a substantive comparison. Interim analyses and the statistical plan are not reported in the registry record. Any interpretation must therefore distinguish the described planning assumptions from analyses actually performed; the registry states that all planned analyses were not performed.
More generally, safety endpoints can be analyzed in several ways, depending on the protocol and the data structure. A report might distinguish event severity, timing, recurrence, or relationship to treatment. Those are general possibilities, not methods that can be attributed to this study. The record identifies the participant-count endpoint and event definitions, but further analytical choices are not reported in the registry record. Statistical language should stay close to what is posted: a small set of descriptive counts, an early stopping statement, and no reported primary endpoint analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 22 outcome measures, including the primary AE and SAE endpoint and secondary measures of pain, physical function, stiffness, patient global assessment, and response. Listing multiple outcomes creates a general concern about multiplicity: when many outcomes or time points are tested, the chance of at least one apparently notable result can increase if testing is not accounted for. Whether and how this study planned to address that issue is not reported in the registry record. The record lists 0 analyses, so there are no reported tests or estimates to interpret with respect to multiplicity.
Several secondary measures were scheduled across repeated follow-up points, including Week 4, 8, 16, 24, 32, 40, 48, 56, and 64. These are outcome time points named in the registry, not evidence that observations were collected at every point. The study ended prematurely, and the record says planned analyses were not performed. Results for these outcomes are not reported in the registry record.
Missing-data handling is also not reported in the registry record. The stated analysis population includes randomized participants who received at least 1 dose, but the record does not describe how unavailable endpoint information, early discontinuation, or incomplete follow-up would enter an analysis. Because follow-up ended early, the planned long-term observation period was not completed as described. No imputation approach, sensitivity analysis, or other missing-data procedure is reported.
The absence of reported multiplicity and missing-data methods does not show that a particular method was or was not used outside the registry entry. It means those details cannot be evaluated from the registry record. The clearest interpretation is that there are no reported analyses of the listed outcomes, and no reported statistical procedures for multiplicity or missing observations.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Tanezumab 2.5 mg | 0 | 1 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Tanezumab 2.5 mg | 0 of 1 |
The serious adverse-event figures list the Tanezumab 2.5 mg group with 1 participant at risk and 0 participants with a serious event. The other-event fields also show 1 at risk and 0 with an event. These are participant counts, not event rates or a comparison with another group. The death field is not populated, so deaths are not reported in the registry record. No top serious-event terms are listed.
These entries should be read as descriptive observations during the recorded follow-up, not as proof that no risk exists. The study was terminated prematurely, and the primary endpoint timeframe ends at early termination, Day 107, rather than the intended long-term period of up to 64 weeks. The posted figures also do not include corresponding adverse-event counts for the other listed dose groups. They cannot establish comparative safety or characterize how event patterns might differ across doses.
The endpoint definition includes events that need not be caused by treatment. The counts therefore concern events meeting the registry definitions, not necessarily events attributed to tanezumab. No analysis of causality, precision, or group differences is reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized, double-masked Phase 3 study intended to evaluate long-term safety of subcutaneous tanezumab in osteoarthritis of the knee. It also documents premature termination following a US FDA-imposed clinical hold and states that all planned analyses were not performed. The posted adverse-event figures show 0 serious events and 0 other events among 1 participant at risk in the Tanezumab 2.5 mg group. Those figures are the specific descriptive findings available for the safety endpoint in the posted results.
They do not establish the absence of risk. A zero observed count in a sparse group cannot show that an event could never occur, and the truncated follow-up cannot describe the complete intended long-term period. The death field is not populated, which means deaths are not reported in the registry record; it should not be read as a reported zero. The absent counts for other listed dose groups also prevent a dose comparison.
The record does not provide a completed statistical analysis, confidence interval, hypothesis test, or estimate comparing tanezumab with another treatment. It therefore does not establish a difference, equivalence, or lack of difference in safety. The listed secondary outcomes do not support conclusions about pain, function, stiffness, or global assessment because analyses are not reported. Planned outcomes and study aims are not substitutes for observed results.
In general, a trial's design can describe how investigators intended to collect evidence, while the results and analyses determine what can be inferred from the observed data. In this case, the available record is informative about the intended study question, the early termination, and the small posted safety count. It is not a complete account of long-term safety or comparative treatment effects. No medical conclusion should be drawn from the displayed count alone.
13. Why This Trial Matters Statistically
This study is statistically important as an example of the difference between a planned trial and an analyzable result. The registry describes randomization, masking, a parallel design, and a long-term safety objective, but also records premature termination and 0 analyses. Design features matter, yet they cannot compensate for the absence of completed outcome analyses.
The case also shows why counts need context. A count of participants with events is straightforward to read, but its meaning depends on the number at risk, the event definition, the observation period, and whether comparable groups are available. Here, the posted adverse-event figures cover 1 participant in the Tanezumab 2.5 mg group, while the intended assessment extended up to 64 weeks and the primary endpoint covers only baseline to early termination, Day 107. The sparse count and curtailed observation do not support a broad safety estimate.
Multiplicity and missing-data questions are relevant whenever a registry lists many outcomes and repeated time points. The record names 22 outcome measures, but does not report analyses or methods for addressing multiplicity or missing observations. Statistical interpretation should not fill those gaps by assuming a particular plan. The explicit statement that planned analyses were not performed is central to understanding why intended outcomes are not findings.
Finally, the record distinguishes transparency about a study's aims from evidence about its results. Registry entries can preserve the endpoint definitions, planned follow-up, and reasons for early termination even when a comparative analysis is unavailable. Careful reading separates those documented features from conclusions that would require more complete outcome data and reported methods.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation is the early termination of a study designed to assess safety over up to 64 weeks. The primary endpoint's stated observation period ends at early termination, Day 107. The record attributes premature termination to a US FDA-imposed clinical hold. Consequently, the posted results do not represent a completed evaluation over the intended long-term period.
The registry records enrollment of 1, and the posted adverse-event figures show 1 participant at risk in the Tanezumab 2.5 mg group. Such sparse descriptive information cannot characterize the range of possible safety outcomes or support stable comparative estimates. Figures for the other listed dose groups are not included in the posted adverse-event results described in the record. A comparator is not identified in the arm descriptions, which are blank.
The registry states that all planned analyses were not performed and lists 0 analyses despite 22 outcome measures. No inferential result, confidence interval, or comparative estimate is reported for the primary endpoint. The record does not report a sample-size justification, interim analyses, or a statistical analysis plan. It also does not report procedures for missing data or multiplicity. The primary population description is truncated, limiting the available detail about analysis eligibility beyond the stated requirement that randomized participants received at least 1 dose.
The safety definitions are broad and include events that need not be causally related to treatment. The posted counts therefore do not establish treatment attribution. The death field is unpopulated, and deaths are not reported in the registry record. These limitations constrain conclusions about both the frequency and the comparative pattern of adverse events.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety Extension Study Of Tanezumab When Administered By Subcutaneous Injection To Patients With Osteoarthritis — NCT01127893.
- Registry record last updated 2021-03-10; status last verified 2021-02.
- Results first posted 2021-03-10.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry identifies NCT01127893 as a terminated Phase 3 randomized, double-masked, parallel study of subcutaneous tanezumab for osteoarthritis of the knee. The intended safety evaluation involved administration every 8 weeks for up to 64 weeks, with listed dose groups of 2.5 mg, 5 mg, and 10 mg. Enrollment is recorded as 1.
The primary endpoint counts participants with AEs and SAEs from baseline to early termination, Day 107. The record says the study was terminated prematurely because of a US FDA-imposed clinical hold and that all planned analyses were not performed. It lists 22 outcome measures and 0 analyses.
The posted adverse-event figures show 1 participant at risk and 0 serious events in the Tanezumab 2.5 mg group; the other-event fields show 1 at risk and 0 with an event. The death field is not populated. No comparative safety analysis is reported in the registry record.