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 Study of Saxagliptin, 5-Hydroxy Saxagliptin, and Metformin Concentrations/Levels in Pediatric Subjects With T2DM (NCT01525225), a na phase 1 study. The primary outcome is Number of Participants With Adverse Events (AEs) , Serious Adverse Events (SAEs), AEs Leading to Discontinuation, Death.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01525225 |
| Phase | Phase 1 |
| Condition | Type 2 Diabetes Mellitus |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | AstraZeneca |
| Results posted | Yes |
2. Clinical Question
Population
Children and adolescents aged 10 to 17 years with Type 2 diabetes mellitus were the intended study population. The registry record says the primary safety population includes participants who received at least one dose of study drug. Enrollment was 4; the posted safety group lists 2 participants at risk for each reported safety measure.
Intervention
The study objective concerns oral administration of a saxagliptin and metformin extended-release fixed-dose combination tablet, and co-administration of saxagliptin with metformin immediate-release tablets. The listed interventions also include metformin immediate-release, saxagliptin, the fixed-dose combination, and metformin extended-release. The registry record does not report a detailed dosing schedule.
Comparator
No control group or randomized comparator is described. The study is recorded as single group, with allocation marked not applicable and masking recorded as none. It therefore does not provide a like-for-like treatment comparison.
Primary question
The stated study purpose is to evaluate pharmacokinetics of saxagliptin, 5-hydroxy saxagliptin, and metformin. The posted primary endpoint, however, counts participants with adverse events, serious adverse events, adverse events leading to discontinuation, or death from Day 1 up to Day 8, plus 30 days. The registry record posts safety counts but no pharmacokinetic results.
3. Trial Design
This is a Phase 1, single-group study with no masking. Allocation is marked not applicable, and the registry record identifies no randomized comparison. The study concerns children and adolescents aged 10 to 17 years with Type 2 diabetes mellitus and has enrollment of 4. Its status is terminated. The registry record does not report why the study was terminated.
The study title and brief description identify pharmacokinetics as the scientific purpose: evaluating saxagliptin, its metabolite 5-hydroxy saxagliptin, and metformin after oral administration of the fixed-dose extended-release combination and co-administration of saxagliptin with immediate-release metformin. The registry lists metformin immediate-release, saxagliptin, saxagliptin/metformin extended-release fixed-dose combination, and metformin extended-release among the interventions. It does not report the detailed sequence or dosing schedule in the record summarized for this analysis.
The primary endpoint is a safety count, not a pharmacokinetic concentration or exposure measure. Its timeframe is Day 1 up to Day 8, plus 30 days. The primary safety population is described as participants who received at least one dose. The posted group lists 2 participants at risk for serious adverse events and 2 at risk for other adverse events. Although total enrollment is 4, these posted risk counts should be read as the denominators for the listed safety results, not as a replacement for the enrollment figure.
The registry record does not report a sample-size justification, a planned statistical analysis, interim analyses, or a detailed protocol. Those omissions mean the study’s planning rationale and intended analysis procedures cannot be reconstructed from the record.
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: A total of 4 participants were enrolled. Two participants were treated and completed the study prior to the termination of the study.
Enrollment
| Stage | Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC |
|---|---|
| STARTED | 4 |
| COMPLETED | 2 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC |
|---|---|
| No longer met study criteria | 1 |
| Other | 1 |
Treated
| Stage | Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC |
|---|---|
| STARTED | 2 |
| COMPLETED | 2 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: All participants who received at least one dose of study drug.
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: All participants who received at least one dose of study drug.
| Characteristic | Unit | Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC |
|---|---|---|
| Participants analysed | 2 | |
| Age, Continuous | years | 13.0 (10.0 to 16.0) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: Black/African American | participants | 1 |
| Race/Ethnicity, Customized: White | participants | 1 |
| Region of Enrollment: United States | participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Adverse Events (AEs) , Serious Adverse Events (SAEs), AEs Leading to Discontinuation, Death, measured over Day 1 up to Day 8, plus 30 days.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with adverse events, serious adverse events, adverse events leading to discontinuation, or death during Day 1 up to Day 8, plus 30 days. The registry defines an adverse event as a new unfavorable symptom, sign, or disease, or a worsening of a pre-existing condition; a causal relationship with treatment is not required. A serious adverse event is defined by outcomes or circumstances such as death, life-threatening events, significant disability, hospitalization, or other specified serious consequences. The record also defines treatment-related events using relationship categories, but the posted primary endpoint title does not provide separate counts by relationship.
General: safety counts are used to describe events observed during and after exposure, including events that may not be caused by the study drug. A participant count answers how many people experienced at least one event in a category; it is not the same as a count of all event episodes. Such counts can help describe what was observed, but they do not establish whether an event was caused by treatment.
The posted endpoint is a safety measure. It does not itself report the pharmacokinetic quantities named in the study purpose. No concentration or exposure results are reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted safety results describe a very small group. For serious adverse events, 0 of 2 participants at risk are listed as affected. For other adverse events, 2 of 2 participants at risk are listed as affected. These are descriptive counts from the registry record; they are not estimates from a randomized comparison. The record does not post uncertainty intervals, hypothesis tests, or adjusted analyses for these outcomes.
The registry records total enrollment of 4, while the safety results list 2 participants at risk in the single reported group. The record does not explain the difference between total enrollment and the posted risk counts. The at-risk counts are therefore the appropriate denominators to use when describing these specific posted results, while noting that the registry does not clarify the full disposition of all enrolled participants.
No serious adverse event terms are listed among the top serious terms. The death value is not reported in the registry record. The endpoint title also includes events leading to discontinuation, but separate counts for that component are not reported in the registry record. A count of zero for serious events should not be read as evidence that the risk is absent: with only 2 participants at risk in the posted group, the data are highly limited in their ability to characterize uncommon outcomes.
These safety counts do not answer the study’s pharmacokinetic objective. Although the study description names saxagliptin, 5-hydroxy saxagliptin, and metformin concentrations or levels, no pharmacokinetic results are reported in the registry record. No conclusion about concentration, exposure, or comparisons between formulations can be drawn from the posted safety counts.
General: a confidence interval expresses the range of values compatible with an estimate under a statistical model and its assumptions. No confidence intervals are posted for these safety counts. Without such intervals, and with a small denominator, the observed counts give only a limited description of the outcomes in this group. They should not be interpreted as precise estimates for a broader population.
The study is single group and has no like-for-like control comparison. Consequently, the results cannot distinguish events related to treatment from events that might have occurred without treatment. The record also does not report an inferential analysis or a statistical plan. The posted information supports description of the listed counts, not a comparative claim or a causal interpretation.
9. Statistical Methods Explained
General: an endpoint is a prespecified or recorded outcome used to describe what happened during a study. Here the primary endpoint is expressed as numbers of participants with safety events, while the stated scientific purpose is pharmacokinetic evaluation. These are distinct kinds of outcomes. Safety counts describe whether participants experienced events; pharmacokinetic results would describe drug or metabolite concentrations or related exposure measures. The registry record reports the former but does not report the latter.
What does a participant count convey?
For a binary outcome such as whether a participant experienced an event, the result is a count of participants with the event and a count at risk. In this study, the posted group has 2 participants at risk for serious adverse events, with 0 affected, and 2 at risk for other adverse events, with 2 affected. These figures describe the recorded group only. They do not count the total number of event episodes, and they do not indicate how severe or long-lasting an event was unless that information is separately reported.
General: a proportion can summarize an event count relative to the number at risk, but no additional derived values are needed to understand these results. The registry record itself posts the counts. With a small group, each participant’s outcome has substantial influence on the overall description. The observed count is therefore not a stable estimate of the frequency that would necessarily be seen in other groups.
Why does the design matter?
General: a control group helps distinguish outcomes under one intervention from outcomes under an alternative condition, provided the comparison is appropriately designed and analyzed. This record describes a single group, no masking, and allocation marked not applicable. It does not describe a like-for-like comparator. The observed safety events therefore cannot be attributed to a particular formulation by comparing them with another group in this study.
General: random allocation, when used, can reduce systematic differences between comparison groups. It is not reported; rather, the study is recorded as single group with allocation not applicable. Masking is recorded as none. The registry record does not report additional procedures intended to limit bias in event assessment. These design details constrain what can be inferred, but they do not change the descriptive meaning of the posted counts.
What can inferential statistics add?
General: inferential procedures use a statistical model to quantify uncertainty or assess a specified hypothesis. A confidence interval communicates uncertainty around an estimate, while a hypothesis test evaluates data against a null hypothesis under stated assumptions. Neither type of result is posted for the primary safety endpoint. The registry record lists 0 analyses. No p-values, confidence intervals, adjusted estimates, or analysis model are reported in the registry record, so there is no inferential result to interpret.
General: over-dispersion is a situation in which the variability in data is greater than a chosen model expects. It can matter for count outcomes when a model assumes a particular relationship between the mean and variance. The posted primary result is a participant-level event count in a very small single group, and the registry record does not report a count model or any assessment of dispersion. It would be inappropriate to assume that an over-dispersion adjustment was planned or used.
How should planning illustrations be understood?
General: sample-size calculations describe how many participants might be needed under specified assumptions about an effect, significance level, allocation, and statistical model. They are planning illustrations, not observed outcomes and not proof that a study was adequately powered. The record describes an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect framed as a fraction of the observed effect. It also distinguishes participants per arm for non-time-to-event outcomes from total events for time-to-event outcomes.
Those assumptions do not describe the recorded study design, which is single group and has no like-for-like control comparison. The registry record does not report that these were the study’s own design assumptions or provide a sample-size justification. Nor does the record report the numerical planning results in the registry record for this analysis. The illustrations should therefore not be treated as the trial’s planned enrollment, observed power, or evidence of a treatment effect.
10. Multiplicity, Missing Data and Analysis Populations
The registry record does not report a statistical analysis plan, a hierarchy of outcomes, or procedures for controlling multiplicity. Multiplicity arises when several outcomes or comparisons are tested; without a prespecified approach, repeated testing can increase the chance of a nominally notable result occurring by chance. The record lists a primary safety outcome and a secondary outcome concerning marked chemistry or hematology laboratory abnormalities, but no analysis results are reported for either outcome in the registry record. No multiple-testing adjustment is reported.
Missing-data handling is not reported in the registry record. The record does not explain whether any participants lacked safety follow-up, how incomplete observations were handled, or whether data were imputed. It also does not explain why the posted safety denominators are 2 when enrollment is 4. This distinction matters: enrollment describes the number recorded as enrolled, while the risk denominator for an outcome describes the participants included in that outcome’s posted count. The record does not provide enough detail to reconcile them.
The primary safety population is described as all participants who received at least one dose of study drug. The record does not provide a further analysis-population definition or participant-level disposition. General: an analysis population specifies which participants contribute to a particular analysis; different definitions can yield different results when participation, exposure, or follow-up is incomplete. No alternative population or sensitivity analysis is reported in the registry record.
The registry lists 0 analyses. Thus, there is no reported inferential result for which multiplicity adjustment, missing-data assumptions, or population definitions can be evaluated. These are not proof that no procedures were used; they are details not reported in the registry record.
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 |
|---|---|---|---|
| Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC | 0 | 2 | 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 |
|---|---|
| Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC | 2 of 2 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Metformin + Saxagliptin + Saxagliptin/Metformin XR FDC |
|---|---|---|
| Headache | Nervous system disorders | 2 of 2 |
The posted safety group lists 0 serious adverse events among 2 participants at risk and 2 participants with other adverse events among 2 at risk. These are participant counts, not totals of every event episode. The registry record does not list top serious adverse event terms, and the death count is not reported in the registry record. Separate counts for adverse events leading to discontinuation are also not reported in the registry record.
The registry’s definition of an adverse event does not require a causal relationship to study treatment. A serious adverse event is defined by seriousness criteria, including specified consequences such as hospitalization or life-threatening events. The record’s definition of treatment-related includes certain, probable, possible, or missing relationship to study drug, but the posted counts do not separate events by relationship category. They therefore should not be read as counts of events established to have been caused by treatment.
General: zero observed events in a small group does not establish that an event cannot occur. A small number of participants provides limited information about uncommon outcomes. These counts describe what the registry reports for the group and timeframe, not a precise estimate of safety in a wider population.
12. What the Result Does, and Does Not, Mean
The results support a narrow descriptive statement: in the posted safety group, no participant among the 2 at risk is recorded with a serious adverse event, while both participants at risk are recorded with other adverse events. The observation period is listed as Day 1 up to Day 8, plus 30 days. The record’s event definitions include events that may not have a causal relationship to treatment.
The results do not establish that treatment caused the reported events, nor do they establish that treatment prevented serious events. There is no control group for comparison, and no statistical analyses or uncertainty intervals are reported. The small risk denominators sharply limit how precisely the posted counts describe outcomes beyond this group.
The study’s stated purpose is pharmacokinetic evaluation of saxagliptin, 5-hydroxy saxagliptin, and metformin. The registry record does not report concentrations, exposure estimates, or comparative pharmacokinetic findings. The safety endpoint cannot be used as a substitute for those missing results. The record also does not report outcomes that would support a conclusion about clinical benefit.
The secondary outcome concerns participants with marked chemistry or hematology laboratory abnormalities, but its results are not reported in the registry record. Reasons for termination, participant disposition, and detailed dosing information are also not reported in the registry record. These gaps prevent a fuller reconstruction of the study conduct and results.
General: a clinical trial result is most informative when interpreted in light of its design, outcome definitions, analysis methods, and uncertainty. Here, the single-group design and limited posted counts favor cautious description rather than causal or comparative interpretation. The findings describe only the safety information recorded for this study; they should not be generalized as a precise estimate for all children and adolescents with Type 2 diabetes mellitus.
13. Why This Trial Matters Statistically
This record illustrates why a study’s stated purpose and its posted primary endpoint need to be read separately. The study is described as an evaluation of pharmacokinetics, while the primary outcome listed in the registry counts adverse events, serious adverse events, discontinuations due to adverse events, and deaths. A safety count cannot answer a question about drug concentrations or exposure. The registry record reports no pharmacokinetic results, so the stated pharmacokinetic objective cannot be evaluated from the posted results.
The study also shows how design limits statistical interpretation. A single group without a like-for-like comparator can describe what was observed, but it cannot provide a direct between-group estimate. The absence of masking is another recorded design feature, and the registry record does not report further steps for limiting outcome-assessment bias. These details matter when deciding whether results support description, comparison, or causal inference.
The small enrollment and the posted risk counts make precision especially important. The observed counts are simple to state, but they contain limited information about uncommon outcomes or about outcomes in a wider population. The record does not report confidence intervals or hypothesis tests, so readers cannot use inferential results to quantify uncertainty.
Finally, the registry record includes little information about analysis methods, missing data, participant disposition, and the reason for termination. Recognizing what is not reported is part of statistical interpretation: it prevents descriptive counts from being mistaken for a complete assessment of safety, pharmacokinetics, or treatment effects.
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 immediate limitation is the small enrollment of 4 and the smaller posted risk denominators of 2 for the reported safety measures. The registry record does not explain this difference or provide participant-level disposition. As a result, the scope of the posted safety counts is limited and the record does not clarify how all enrolled participants contributed to the endpoint.
The study is recorded as single group, with no masking and allocation marked not applicable. No like-for-like comparator is described. The safety counts therefore cannot support a comparative treatment estimate, and observed events cannot be separated from events that might have occurred without treatment. The registry record does not report a detailed protocol, dosing schedule, or additional procedures for assessing outcomes.
The posted primary endpoint concerns safety, but the stated study purpose is pharmacokinetic evaluation. No pharmacokinetic results are reported in the registry record. The secondary laboratory-abnormality outcome is listed, but its results are not reported in the registry record. Separate results for discontinuations and deaths are also not reported in the registry record.
The record lists 0 analyses and does not report an analysis plan, confidence intervals, hypothesis tests, missing-data procedures, or multiplicity procedures. It does not report a sample-size justification, interim analyses, or the reason for termination. These omissions limit assessment of the intended analysis, completeness of follow-up, and the context for the posted counts. They should be understood as limitations of the information reported in the registry record, not as evidence that any particular procedure was or was not performed.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of Saxagliptin, 5-Hydroxy Saxagliptin, and Metformin Concentrations/Levels in Pediatric Subjects With T2DM — NCT01525225.
- Registry record last updated 2015-06-22; status last verified 2015-05.
- Results first posted 2014-08-26.
- 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
NCT01525225 is a terminated Phase 1, single-group study of saxagliptin and metformin in children and adolescents aged 10 to 17 years with Type 2 diabetes mellitus. Enrollment is 4. The stated purpose is pharmacokinetic evaluation of saxagliptin, 5-hydroxy saxagliptin, and metformin, but no pharmacokinetic results are reported in the registry record.
The primary endpoint counts participants with adverse events, serious adverse events, adverse events leading to discontinuation, or death from Day 1 up to Day 8, plus 30 days. The posted group lists 0 of 2 participants at risk with serious adverse events and 2 of 2 with other adverse events. The death count and separate discontinuation results are not reported in the registry record. No inferential analyses are reported, and the single-group design does not provide a like-for-like comparator.