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 PTH Analog Type II Odontoid Fracture (NCT04760782), a non-randomized phase 2 study. The primary outcome is Fracture Union.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04760782 |
| Phase | Phase 2 |
| Condition | Odontoid Fracture |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | Single |
| Enrollment | 22 |
| Arms in the primary outcome | n/a |
| Lead sponsor | David Lunardini |
| Results posted | Yes |
2. Clinical Question
Population
Older adults with an acute Anderson and D’Alonzo type II odontoid fracture identified on cervical spine CT. The eligibility description specifies people at least 50 years old and a fracture identified within 3 weeks.
Intervention
Daily self-administered injection of 80 mcg abaloparatide for 8 weeks, together with hard-collar immobilization for 12 weeks.
Comparator
A historical control group of patients treated with hard-collar immobilization alone for 12 weeks. Because this was not a randomized comparison, the groups should not be treated as if they were assigned under identical conditions.
Primary question
At 3 months after injury, what was the median percentage of bridging bone on cervical CT, and how did the prospective treatment group’s fracture union compare with historical treatment? The registry record describes this as a pilot efficacy trial, but does not report the primary outcome values.
The clinical question is about radiographic healing. It is not a question about whether the treatment changes pain, disability, fracture movement, or fracture shape, although the record lists those as secondary outcomes. Nor does the record establish that the groups were exchangeable: the comparator was historical, and allocation was non-randomized. Differences in patient characteristics, care, or measurement could therefore contribute to any apparent group contrast.
The study record describes prospective collection of data before termination. It reports outcome imaging for the participants who completed the study in the treatment group and the active control participants who completed the study. Those imaging counts are very small, and the registry record does not provide the actual union measurements. As a result, the clinical question can be identified, but the magnitude and precision of the answer cannot be assessed from the reported primary outcome information.
3. Trial Design
The registry classifies this as a phase 2 study with non-randomized allocation and a single-group model. The study description also identifies a prospective cohort and a historical control group. These descriptions convey an important design feature: patients receiving abaloparatide were not randomly assigned against contemporaneous patients receiving collar treatment alone. The comparison uses historical treatment instead.
The treatment group was scheduled to receive daily self-administered 80 mcg abaloparatide for 8 weeks, alongside hard-collar immobilization for 12 weeks. The historical control group received hard-collar immobilization alone for 12 weeks. The study’s stated aim was to compare fracture union under these treatment approaches. The record lists single masking, but does not report whom masking applied to or how it was implemented.
The registry lists enrollment as 22 and status as terminated. The dates recorded are a start date of 2022-05-18 and a primary completion date of 2023-08-14. These registry entries do not establish how many participants completed follow-up or contributed to each particular outcome. For the primary outcome imaging, the record specifically reports data for participants who completed the study: N=1 in the treatment group and N=2 in the active control group.
Termination means the study ended without proceeding as originally intended, but the reason for termination is not reported in the registry record. The record also does not report a detailed protocol, the planned sample-size justification, or whether interim analyses were planned. The prospective treatment cohort and historical comparator can offer preliminary observations, but this design is more vulnerable than random allocation to differences between groups that may affect healing independently of treatment.
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.
Overall Study
| Stage | Treatment Group | Historical Control Group |
|---|---|---|
| STARTED | 5 | 17 |
| COMPLETED | 1 | 17 |
| NOT COMPLETED | 4 | 0 |
Analysis population for the primary outcome, as defined in the registry: Data analyzed and reported include all outcome data prospectively collected for this study before study termination. Outcome imaging was collected for all participants who completed the study in the treatment group (N=1) and all active control participants who completed the study (N=2). Outcome imaging was not collected from the electronic medical record for N=15 retrospectively review-only control participants before study termination.
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.
| Characteristic | Unit | Treatment Group | Historical Control Group | Total |
|---|---|---|---|---|
| Participants analysed | 5 | 17 | 22 | |
| Age, Continuous | years | 82 (75 to 86) | 80 (53 to 90) | 80 (53 to 90) |
| Sex: Female, Male: Female | Participants | 3 | 7 | 10 |
| Sex: Female, Male: Male | Participants | 2 | 10 | 12 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 4 | 17 | 21 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 5 | 17 | 22 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 5 | 17 | 22 |
| History of osteoporosis: Yes, No | Participants | 0 | 5 | 5 |
| History of fragility fracture: Yes, No | Participants | 0 | 2 | 2 |
| BMI | kg/m2 | 22 (21 to 23) | 24 (20 to 34) | 24 (20 to 34) |
6. Primary Endpoint
The registry lists the primary outcome as Fracture Union, measured over 3 months after injury.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | percentage of total healing |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is fracture union, expressed as the percentage of total healing and assessed as the percentage of bridging bone on cervical CT. The registry specifies a median with a full range as the summary, measured 3 months after injury. In general, a radiographic measure of bridging bone describes the extent of visible bony connection across the fracture site. A continuous percentage can retain gradations of healing that a simple yes-or-no classification would not capture.
The median is the middle value in an ordered set of observations. It is often useful when measurements are skewed or when extreme observations could pull an average away from the typical value. A full range describes the span from the lowest to the highest observed measurement, but with very few observations it gives little information about the shape or stability of the underlying distribution.
The endpoint is relevant to the study’s focus on fracture healing, but it does not by itself describe symptoms, function, complications, or the course of healing over time. Those are different questions; the registry lists neck disability, neck pain, motion, and fracture characteristics among secondary outcomes. The primary outcome values themselves are not reported in the registry record, so the amount of bridging bone and its variability cannot be evaluated from the available information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically focused comparison: prospective treatment with abaloparatide plus collar immobilization versus historical collar treatment alone. However, it does not report the median percentage of bridging bone or the full range for either group. Consequently, the direction, size, and precision of the primary outcome contrast cannot be described from the record. No conclusion about the observed fracture-union results is justified from the available primary outcome information.
The outcome imaging counts reported for participants who completed the study are N=1 in the treatment group and N=2 in the active control group. These small numbers sharply limit what an estimate could establish, even if group summaries were available. A single observation cannot characterize variation within a group, and a small historical group cannot reliably represent the range of outcomes that might occur in similar patients. The registry does not report confidence intervals for the primary outcome.
In general, a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the analysis. It is not a guarantee that the true value lies in the interval, and its meaning depends on the design and statistical model. For a small, non-randomized comparison, uncertainty includes not only sampling variability but also concerns about comparability between groups and the way historical information was assembled. No interval or adjusted comparison is reported in the registry record.
The treatment and historical groups may differ in ways that influence healing. Randomization is absent, and the record does not provide enough participant-level characteristics or adjustment details to assess whether important differences were controlled. Historical controls can be informative, but changes in clinical practice, selection, follow-up, and outcome assessment may complicate comparisons. These are design considerations, not evidence that a particular bias occurred.
The registry reports status as terminated and provides outcome imaging for only the participants who completed the study in each group. The reason for termination, the number of participants with missing primary outcome data, and the handling of missing observations are not reported in the registry record. Therefore, the degree to which the available imaging represents everyone who began participation cannot be determined.
Safety information is also limited. The registry lists serious adverse events and deaths by group, but the small numbers and the absence of detailed event timing, attribution, and context prevent a causal interpretation. Taken together, the record supports a description of the study question and design, but does not provide enough primary efficacy information to estimate or compare fracture union reliably.
9. Statistical Methods Explained
The registry classifies the study as non-randomized and single-group, while the study description says it is a prospective cohort with a historical control. The practical implication is that the intervention group and comparison group were not created by random assignment within the same trial period. In general, randomization helps balance both measured and unmeasured prognostic factors across groups on average. Without it, a difference in outcome can reflect treatment, baseline differences, or other differences associated with how the groups were assembled.
What does a historical control change?
A historical control uses outcomes from patients treated earlier or outside the prospective treatment cohort rather than a contemporaneous randomized comparison. This can provide a benchmark, particularly in an exploratory study, but it relies on the historical patients being sufficiently comparable and on outcome definitions and care being consistent. The registry record does not report detailed matching, adjustment, or other methods to address these concerns. The comparator should therefore be read as historical context rather than a randomized control.
What does the primary summary describe?
The primary endpoint is a median percentage of bridging bone on cervical CT at 3 months after injury, with the full range. A median gives a measure of the center of the observed values that is less affected than a mean by unusually high or low measurements. The full range gives the observed extremes. In general, neither statistic alone describes the full distribution, and a range can be especially unstable when only a few measurements are available. The primary outcome values are not reported in the registry record, so no endpoint estimate or contrast can be interpreted.
Why does the number of observations matter?
For primary outcome imaging, the record reports N=1 for the treatment-group participants who completed the study and N=2 for active control participants who completed the study. With such limited outcome information, a group median and range would have little capacity to characterize the broader patient population. In general, a larger sample can improve the precision of an estimate, but sample size alone does not fix bias from non-random allocation, incomplete outcome collection, or non-comparable measurement.
The registry lists enrollment as 22, but that entry should not be confused with the number contributing to the primary outcome imaging. Enrollment, completion, and outcome-specific analysis are distinct concepts. The record does not report a complete participant flow or explain the relationship between the enrollment entry and the small imaging counts.
How should uncertainty be understood?
In general, a confidence interval gives a range of values compatible with the observed data under a specified statistical model and its assumptions. A narrow interval indicates more precision than a wide one, but does not rule out systematic bias. No confidence interval for the primary endpoint is reported in the registry record. The record also does not report an adjusted effect estimate or a statistical test for the primary comparison.
Over-dispersion is a general issue in data where observed variation is greater than a simple statistical model expects. If such a model is used without accounting for the extra variability, uncertainty can be understated. This study’s primary endpoint is a percentage summarized by a median and full range; the registry record does not report a model-based analysis or an over-dispersion assessment. This general concept should not be taken to imply that over-dispersion was present in this trial.
What is the role of the planning illustration?
The sample-size assumptions describe a planning illustration based on an observed effect, not the trial’s own design justification. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. For time-to-event calculations, the illustration gives total events, while other calculations give participants per arm. These are planning quantities, not observed power and not evidence that the study was adequately sized. The registry record does not report the trial’s own sample-size justification.
A planning calculation based on an observed effect is especially uncertain when the estimate comes from very few observations. In general, an effect estimated from a small sample may be unstable, and using it as a planning target does not establish the effect that a future study will observe. Planning illustrations can help show how assumptions influence design needs, but they do not replace a prespecified rationale grounded in the research question and a defensible effect size.
What can be inferred from the design labels?
Phase 2 describes the development stage recorded for the study; it does not itself establish efficacy. Single masking is the registry classification, but the identity of the masked party and the procedures are not reported. The single-group model label coexists with the description of a historical control; these entries do not turn the comparison into a randomized two-arm trial. Interpretation should follow the actual cohort and historical-comparator structure, while recognizing that further design details are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists six outcome measures, including fracture union and secondary measures concerning fracture characteristics, motion, neck disability, and neck pain. Considering multiple outcomes can create multiplicity: in general, the more separate statistical questions evaluated, the greater the chance of finding an apparently unusual result by chance if each is treated as a standalone test. A prespecified hierarchy or adjustment can address some multiplicity concerns, but the analysis plan and any multiplicity procedure are not reported in the registry record.
The registry lists zero analyses. That does not mean that no data were collected: it separately states that outcome data were prospectively collected before termination and describes outcome imaging for participants who completed the study. It does mean the record does not provide a reported analysis for those outcomes. The primary endpoint values, statistical comparisons, and analysis methods are not reported in the registry record.
Missing-data handling is also not reported. The imaging information is explicitly limited to completed participants: N=1 in the treatment group and N=2 in the active control group. The record does not provide the number of participants who lacked an outcome, reasons for non-completion, or whether any imputation or sensitivity analysis was used. Those omissions prevent assessment of whether missingness could have affected the observed outcome summaries.
The analysis population is not reported in enough detail to determine whether the primary outcome analysis was intended to include all enrolled participants, only those completing treatment, or another subset. The registry says that data analyzed and reported include prospectively collected outcome data before termination, but does not specify a broader analysis-population definition. These distinctions matter because results among completers may not represent everyone who entered a study.
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 |
|---|---|---|---|
| Treatment Group | 1 | 5 | 20.0% |
| Historical Control Group | 0 | 2 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment Group | 1 of 5 |
| Historical Control Group | 0 of 2 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment Group | 0 of 5 |
| Historical Control Group | 0 of 2 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment Group | Historical Control Group |
|---|---|---|---|
| Respiratory failure | Respiratory, thoracic and mediastinal disorders | 1 of 5 | 0 of 2 |
| Dizziness; Fatigue/low energy; Respiratory failure | Respiratory, thoracic and mediastinal disorders | 1 of 5 | 0 of 2 |
Serious events with the highest arm-level rate: respiratory failure (20.0%), dizziness; fatigue/low energy; respiratory failure (20.0%).
The registry reports serious adverse events for the treatment and historical control groups. In the treatment group, 5 participants were listed as at risk for serious adverse events and 1 as affected; the historical control group lists 2 at risk and 0 affected. The record also lists other adverse events: 5 at risk and 0 affected in the treatment group, and 2 at risk and 0 affected in the historical control group. Deaths are listed as 1 in the treatment group and 0 in the historical control group.
The serious-event terms listed include respiratory failure at 20.0% and dizziness; fatigue/low energy; respiratory failure at 20.0%. The registry does not provide enough detail in the record to determine how these terms relate to individual events, whether categories overlap, or what time period and attribution rules apply. The cause of the listed death is not reported in the registry record.
These figures are descriptive. The groups are non-randomized, the comparator is historical, and the reported numbers are small. They do not establish that treatment caused or prevented an event, and they do not support a reliable comparative safety estimate. Event timing, severity details beyond the registry categories, and investigator assessments of relatedness are not reported.
12. What the Result Does, and Does Not, Mean
The record establishes that a prospective cohort study was intended to examine abaloparatide alongside hard-collar immobilization for type II odontoid fractures, using historical collar-only treatment as the comparator. It also identifies fracture union, measured by bridging bone on CT at 3 months after injury, as the primary outcome. These details clarify the research question and the kind of evidence the study was designed to collect.
The available record does not provide the primary outcome values. It therefore cannot show the median bridging bone in either group, the full range, or the magnitude and direction of a difference. The outcome imaging counts for participants who completed the study were N=1 and N=2, and the study is listed as terminated. The reported information is insufficient to determine whether the intended comparison yielded an informative estimate.
Even if group outcome values were available, a non-randomized historical comparison would require caution. Group differences could reflect factors other than the intervention, and the registry record does not report adjustment methods that would address this possibility. The very limited imaging counts would also make estimates imprecise and highly sensitive to individual observations.
The record does not establish that abaloparatide improves fracture union, does not establish that it has no effect, and does not establish a safety advantage or disadvantage. The serious adverse event and death entries are descriptive and cannot be interpreted causally in this design. More broadly, the absence of reported primary results is not evidence that the treatment did or did not affect healing. It means the relevant outcome comparison cannot be evaluated from the information reported in the registry record.
13. Why This Trial Matters Statistically
This study raises a useful statistical question about how to evaluate a treatment intended to influence a measurable healing process. Its primary endpoint is a quantitative CT measure rather than a simple binary label, and the registry specifies both a median and a full range. That makes the distinction between describing observed measurements and estimating a dependable treatment contrast especially important.
The design also illustrates why a historical comparator is not equivalent to randomization. Historical data may offer context when prospective enrollment is limited, but a comparison can be affected by differences in patient selection, clinical practice, follow-up, or measurement. Statistical adjustment can sometimes address recorded differences, but it cannot automatically remove unmeasured differences, and the registry record does not report an adjustment strategy.
The primary imaging counts are particularly important to interpretation. A summary based on very few observations can change substantially when an individual value changes, while offering little information about variability across the intended population. Reporting the estimate, uncertainty, missingness, and analysis population would be needed to judge what the study learned from its observations. Those primary outcome results are not reported in the registry record.
The termination status adds a further reason to distinguish study intent from evidential conclusions. The record identifies the study’s question and some collected data, but the reason for termination and a complete account of outcome availability are not reported. This case therefore underscores that registration details, completion status, and reported results answer different questions. A study can be scientifically relevant while still leaving its intended treatment comparison unresolved in the available record.
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 most direct limitation is that the primary endpoint results are not reported in the registry record. Although the endpoint and its timing are specified, there are no reported group medians, ranges, or comparative estimates to evaluate. The record also does not provide confidence intervals, a statistical test, or an adjusted analysis for fracture union.
The primary outcome imaging counts are limited to N=1 in the treatment group and N=2 in the active control group among participants who completed the study. The enrollment entry of 22 does not clarify how many participants entered each group, completed follow-up, or had an outcome measured. A participant flow, reasons for missing outcomes, and missing-data methods are not reported.
The prospective cohort was compared with a historical control, and allocation was non-randomized. The record does not report detailed baseline characteristics, matching, statistical adjustment, or procedures to ensure consistency of care and outcome assessment across the groups. These omissions limit the ability to evaluate comparability and possible sources of bias.
The registry lists the study as terminated, but the reason is not reported. It also does not report a detailed statistical analysis plan, sample-size justification, analysis-population definition, or multiplicity strategy. Single masking is recorded, but who was masked and how masking was conducted are not reported. The safety entries lack detailed information on timing, attribution, and the cause of the listed death. Together, these limitations mean that the record supports description of the study design and reported safety counts, but not a robust estimate of the primary treatment contrast.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: PTH Analog Type II Odontoid Fracture — NCT04760782.
- Registry record last updated 2024-09-19; status last verified 2024-08.
- Results first posted 2024-09-19.
- 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
NCT04760782 is a phase 2, non-randomized study listed as terminated. Its registry description identifies a prospective cohort of patients with acute type II odontoid fractures and a historical control group. The treatment group was assigned daily self-administered 80 mcg abaloparatide for 8 weeks plus hard-collar immobilization for 12 weeks; the historical control received collar immobilization alone for 12 weeks.
The primary outcome was fracture union, defined as the percentage of bridging bone on cervical CT, summarized by the median and full range at 3 months after injury. The registry lists enrollment as 22 and records dates of 2022-05-18 and 2023-08-14 for study start and primary completion. Outcome imaging among participants who completed the study is reported for N=1 in the treatment group and N=2 in the active control group. Primary outcome values and the reason for termination are not reported in the registry record.