A Multiple Dose Study of LY2541546 in Healthy Postmenopausal Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Multiple Dose Study of LY2541546 in Healthy Postmenopausal Women (NCT01742091), a randomized phase 1 study. The primary outcome is Number of Participants With One or More Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration.

2. Clinical Question

3. Trial Design

This was a Phase 1, randomized, double-masked, parallel-group study sponsored by Eli Lilly and Company. It enrolled 59 healthy postmenopausal women. The study began in 2009-09, had a primary completion date of 2010-03, and is marked completed in the registry. The registry does not report the randomization procedure, concealment method, or how masking was maintained for each group beyond describing placebo doses used in certain active-treatment arms.

Five active-treatment regimens are listed, using subcutaneous or intravenous administration and different dose schedules. Each listed active regimen continued for 8 weeks. The placebo group received placebo intravenously or subcutaneously once every 2 weeks for 8 weeks. Some active-treatment regimens included placebo administrations at specified weeks to maintain the blind. The registry does not give a rationale for the selected doses or schedules, or report whether any participants changed treatment or stopped early.

The study’s stated aims included safety and tolerability, pharmacokinetics, pharmacodynamics, and whether antibodies to the study drug formed. The posted secondary outcomes include drug concentration over a dosing interval at steady state, change from baseline in lumbar spine bone mineral density at Day 85, anti-LY2541546 antibodies, and change from baseline in P1NP. The registry lists four posted secondary outcomes. Although five outcome measures are recorded overall, no analyses are listed. The statistical analysis plan and any sample-size justification are not reported in the registry 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants who received 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 study drug.

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With One or More Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration, measured over Day 1 through Day 141.

The primary endpoint counts participants who had one or more serious adverse events that the investigator considered related to study drug administration. Its timeframe is Day 1 through Day 141, and the stated population is all participants who received study drug. The registry defines an SAE through consequences such as death, initial or prolonged inpatient hospitalization, a life-threatening experience, persistent or significant disability or incapacity, congenital anomaly or birth defect, or another event the investigator considers significant. This outcome is a participant count: a person with more than one qualifying event still contributes to the count of participants with one or more such events.

General statistical context: serious adverse events are used in safety assessments because they capture events with major consequences or significance, rather than every symptom or adverse event. Investigator attribution is part of this endpoint: the event must be considered related to study drug administration, not merely occur during follow-up. As a result, this measure does not represent all serious events regardless of attribution, and it does not describe the overall frequency or severity of non-serious adverse events.

The registry’s primary outcome results list zero participants in every treatment arm. A separate adverse-event listing, however, reports one related serious event in the 750 mg LY2541546 IV Q2W group. The record does not explain this difference, so the primary endpoint result requires that qualification.

7. Results Posted in the Registry

• 270 mg LY2541546 SC Q2W: 0.0% (0/11) versus 0.0% (0/12) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0); unadjusted two-proportion z-test p = n/a.
• 270 mg LY2541546 SC Q4W: 0.0% (0/10) versus 0.0% (0/12) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary participant-level outcome: whether a participant had one or more investigator-related serious adverse events during the stated follow-up. General statistical context: a binary outcome records membership in one of two categories, such as experienced the event or did not experience the event. It does not retain distinctions among the number of events per person, event duration, or event severity beyond the endpoint’s qualifying definition.

What does the risk difference describe?

The registry gives risk-difference comparisons for two active-treatment groups against placebo. A risk difference expresses the difference between the event proportions in two groups, on the original proportion scale. The posted estimates for the 270 mg LY2541546 SC Q2W versus placebo comparison and the 270 mg LY2541546 SC Q4W versus placebo comparison are both 0.0. Their reported lower and upper limits are also 0.0. The registry does not report a comparison for the other active-treatment arms, so those pairwise estimates should not be generalized to every dose or administration schedule.

General statistical context: when few or no events are observed, estimates of relative measures can be especially difficult to interpret, and methods may require special handling. The registry record does not state the statistical method, any continuity correction, or other modeling choices used for these comparisons. The reported estimates and limits can be described, but the calculation procedure cannot be reconstructed from the registry record.

Why are zero event counts difficult to interpret?

A zero count is an observation, not proof that the underlying event risk is zero. With small groups, an event that occurs infrequently may simply not appear in the observed participants. General statistical context: uncertainty about an event rate depends on both the number of observed events and the amount of information from participants at risk. A small group with no observed events can still be compatible with a range of underlying risks. The registry does not provide confidence intervals for the separate arm-level counts, and no additional interval calculation is presented.

There is an additional issue beyond ordinary sampling uncertainty: the primary outcome lists no related serious events in the 750 mg LY2541546 IV Q2W arm, whereas the adverse-event listing reports one. This is not a question that a statistical method can resolve without clarification of the underlying records and definitions. The inconsistency should be retained as a limitation rather than selecting one entry as definitive.

What does the design contribute?

Random allocation and double masking are stated design features. General statistical context: randomization is intended to balance prognostic factors across assigned groups on average, while masking can reduce the influence of treatment knowledge on participant experience and outcome assessment. The registry does not report the allocation sequence, concealment details, or the practical procedures used to preserve masking. It also does not report baseline characteristics, so the balance of participant characteristics cannot be assessed from these registry entries.

The parallel-group structure means the listed regimens were assigned to separate groups rather than being described as a crossover sequence. The study includes multiple active-treatment schedules and a placebo group, but the registry record does not report a prespecified primary comparison hierarchy or explain why particular pairwise comparisons are posted. It would therefore be inappropriate to infer that the two available comparisons were the only comparisons planned.

What analyses are not documented?

The registry lists no analyses. The statistical analysis plan, handling of missing observations, analysis populations beyond the primary outcome population description, and any interim analyses are not reported in the registry record. No conclusions about adjustment, model choice, subgroup analysis, or multiplicity correction can be drawn. General statistical context: these details matter because they determine which participants contribute to each estimate, how uncertainty is quantified, and how multiple comparisons are interpreted. Without them, the safest reading is descriptive: report the posted counts and estimates, identify the record’s internal inconsistency, and avoid treating the estimates as a complete account of the study’s inferential analysis.

10. Confidence Intervals and Precision

Precision is limited by the small arm sizes and the rarity of the recorded primary events. The listed group sizes are 9.0, 11.0, 10.0, 9.0, 8.0, and 12.0 participants. The primary results report zero participants with a related serious adverse event in each arm. The record does not provide confidence intervals for these separate arm-level counts. Without intervals or a stated method, the exact range of event frequencies compatible with these observations cannot be described from the registry results.

For the two posted risk-difference comparisons, the estimate and both limits are 0.0. Those reported values are precise in the narrow sense that the limits coincide with the estimate, but they do not establish that the true group difference is known without uncertainty. The registry does not describe the interval method. In particular, the reported values sit alongside zero counts and an inconsistent serious-event entry for one active-treatment arm. The comparison intervals therefore should not be treated as resolving either the sparse-data uncertainty or the record discrepancy.

General statistical context: confidence intervals describe uncertainty under a specified statistical procedure and its assumptions. Their interpretation depends on the analysis method and on the data being analyzed consistently. A narrow or degenerate interval is not automatically informative when event counts are sparse or when the underlying entries conflict. No interval for an overall safety rate, no interval for the separate adverse-event listing, and no uncertainty estimates for the secondary outcomes are reported in the registry record.

The small groups also limit the ability to characterize uncommon events and compare schedules. This is a limitation of the amount of information, not evidence that an unobserved event cannot occur. The registry’s posted results support describing what was recorded in these participants, but they do not precisely establish rates in a wider population.

11. Multiplicity, Missing Data and Analysis Populations

The study has several arms and a range of stated objectives. In addition to the primary serious-adverse-event outcome, the registry lists pharmacokinetic and pharmacodynamic outcomes, including drug exposure, lumbar spine bone mineral density, anti-LY2541546 antibodies, and P1NP. Multiple outcomes and possible comparisons create a general statistical concern: when many hypotheses are examined, the chance of at least one apparently notable result can increase unless the analysis plan addresses multiplicity.

The registry lists four secondary outcomes and no analyses. It does not report a hierarchy among outcomes, a multiplicity adjustment, which comparisons were prespecified, or whether any analyses were exploratory. These details are not reported in the registry record. Consequently, no claim can be made about whether the study controlled the overall error rate across outcomes or comparisons. The fact that only two risk-difference comparisons are posted does not establish that only two comparisons were planned.

The registry describes the primary population as participants who received study drug. It does not explain how participants who did not receive assigned treatment, withdrew, missed assessments, or had incomplete data were handled. Missing-data counts, reasons for missingness, and imputation or other missing-data methods are not reported in the registry record. The analysis populations for the secondary outcomes are also not specified.

General statistical context: the handling of missing observations can affect estimates, particularly when missingness is related to treatment, tolerability, or outcome status. A clear account of the analysis population and missing-data approach helps readers understand which participants inform a result and what assumptions are being made. Here, the registry entries do not permit that assessment.

The record does not report interim analyses, stopping rules, or a statistical analysis plan. It also does not give a sample-size justification. Any planning illustrations based on observed effects are not evidence of the study’s original design rationale or of observed power. The statistical interpretation should therefore remain descriptive and should not imply that unreported multiplicity or missing-data procedures were or were not used.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: concussion (12.5%).

The primary endpoint is specifically the count of participants with at least one serious adverse event considered related to study drug administration by the investigator. Its timeframe is Day 1 through Day 141. In the primary outcome results, the event count is 0.0 in each of the six arms. This is distinct from a count of all adverse events: the separate adverse-event listing reports non-serious adverse events in every group, with counts varying by arm.

The adverse-event listing reports 0 related serious events for the first four arms and for placebo, but 1 for the 750 mg LY2541546 IV Q2W arm. That entry conflicts with the primary outcome result, which lists zero participants with the endpoint in that arm. The record does not explain the discrepancy. It also lists Concussion at 12.5% among the top serious terms; the record does not explain how that term relates to the conflicting participant counts. These figures should not be combined or interpreted as though they were a reconciled dataset.

Deaths are not reported for the groups in the adverse-event record. General statistical context: an absent death count is not the same as a confirmed zero unless the registry explicitly reports zero. The record gives no further details to clarify that point. The sparse counts and internal inconsistency limit comparisons of safety across groups.

13. What the Result Does, and Does Not, Mean

The results describe a small, randomized, double-masked study in healthy postmenopausal women that evaluated several LY2541546 dose and administration schedules against placebo. The primary outcome was a serious-event count based on investigator attribution during Day 1 through Day 141. The primary results list no participants with a related serious adverse event in any group. A separate adverse-event record, however, lists one related serious event in the 750 mg LY2541546 IV Q2W arm. These conflicting entries prevent a fully consistent summary of the serious-event count for that arm.

These findings do not establish that the underlying risk of serious adverse events is zero. The groups are small, the registry does not provide arm-level confidence intervals for the primary counts, and one arm has inconsistent entries. Nor do the results establish that one dose, route, or schedule is safer than another. Only two pairwise risk-difference comparisons are posted, and their reported estimates and limits are all 0.0. The registry does not describe the calculation method, and the posted comparisons do not cover all active-treatment arms.

The study’s other stated aims included pharmacokinetics, pharmacodynamics, and immunogenicity. The registry lists corresponding secondary outcome measures, but numerical results for those measures are not included in the registry entries. Their inclusion in the record does not show whether any particular change occurred.

General statistical context: a trial result is conditional on its participants, design, outcome definitions, follow-up, and analysis. Results from this study therefore should not be extended automatically to populations or settings not described in the registry. The record also does not report the statistical plan or sample-size justification. The appropriate interpretation is limited to the posted observations, with uncertainty and the serious-event inconsistency made explicit, rather than a medical recommendation or a broad judgment about treatment effects.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of why endpoint definitions and consistency across registry entries matter. The primary outcome is not simply any serious event: it counts participants with one or more serious events that the investigator considered related to study drug administration. The adverse-event listing and primary outcome results do not agree for the 750 mg LY2541546 IV Q2W group. Readers need to distinguish that discrepancy from ordinary uncertainty due to small sample sizes; one is a record-level inconsistency, while the other reflects limited information even when entries are consistent.

The trial also illustrates the challenge of interpreting zero-event findings. The primary outcome lists zero participants in all arms, but the arm sizes are small. Such observations describe what was recorded, yet do not prove that serious events cannot occur or establish precise comparative safety. The two posted risk-difference estimates are zero with limits also reported as zero, but the registry does not identify the interval method. Considering these values without their sparse-data context could give a misleading impression of certainty.

Multiple arms, schedules, routes, and outcomes also make a transparent analysis plan important. The registry lists several secondary measures and no analyses. It does not report a comparison hierarchy, multiplicity approach, or sample-size justification. This prevents readers from determining how the available comparisons relate to planned hypotheses or how missing outcome data were treated.

These features make the record useful for careful statistical reading rather than broad conclusions. It highlights the value of clearly defined outcomes, reconciled event counts, stated analysis populations, and uncertainty estimates. Without those details, interpretation should remain close to the recorded details and acknowledge what cannot be assessed.

15. 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 primary limitation is a conflict between the primary outcome listing and the separate adverse-event listing for the 750 mg LY2541546 IV Q2W group. The first reports zero participants with the primary endpoint, while the second reports 1 related serious event among 8 participants at risk. The registry does not explain whether this reflects different definitions, reporting periods, or data updates. The discrepancy cannot be resolved from the record.

Each treatment group is small, and the primary outcome results do not include confidence intervals for arm-level event counts. The record also does not report a statistical analysis plan, sample-size justification, missing-data procedures, interim analyses, or details of the randomization and masking procedures. The posted comparisons cover only two active-treatment groups versus placebo, leaving the other regimens without reported risk-difference estimates.

The endpoint captures only events meeting the serious-event definition and judged related by the investigator. It does not represent all adverse events, and the registry provides no detailed account of event severity, timing, management, or individual participant courses beyond a listed serious term. The adverse-event record does not report death counts for the groups. Numerical results for the pharmacokinetic and pharmacodynamic outcomes are also not available in the registry record.

The participants are described as healthy postmenopausal women, so the results cannot automatically characterize other populations. The study’s duration and follow-up are described for the primary endpoint, but the record does not supply further information about longer-term outcomes. Together, these limitations restrict interpretation to the posted results and make broad comparisons or conclusions unsupported.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Multiple Dose Study of LY2541546 in Healthy Postmenopausal Women — NCT01742091.
• Registry record last updated 2018-07-18; status last verified 2017-09.
• Results first posted 2018-07-18.
• 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.

19. Record Summary

The registry describes a completed Phase 1 randomized, double-masked, parallel-group study of LY2541546 in healthy postmenopausal women. It lists 59 enrolled participants and evaluates five active-treatment regimens using subcutaneous or intravenous administration, alongside placebo. The primary outcome counts participants with one or more investigator-related serious adverse events from Day 1 through Day 141.

The primary outcome listing reports zero participants with the endpoint in each arm. A separate adverse-event record reports 1 related serious event in the 750 mg LY2541546 IV Q2W group, creating an unresolved inconsistency. The registry lists four secondary outcomes but no analyses. The statistical plan, sample-size justification, missing-data handling, and interim analyses are not reported in the registry record. These results should therefore be read descriptively, with the inconsistency and limited precision kept in view.