A Study of 2 Different Formulations of Blosozumab (LY2541546) in Post Menopausal Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of 2 Different Formulations of Blosozumab (LY2541546) in Post Menopausal Women (NCT02337387), 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

The registry identifies this as a Phase 1, randomized, double-blind study of two blosozumab formulations in postmenopausal women. Its official title describes a multiple-dose study evaluating safety, tolerability, and pharmacokinetics. The listed condition is postmenopausal osteoporosis. The record gives an enrollment of 28 and lists the study status as terminated. The reason for termination is not reported in the registry record.

The arm descriptions distinguish Part A from Part B. In Part A, participants in the blosozumab and placebo groups were described as receiving two subcutaneous injections in week 1, weekly injections in weeks 2 to 6, and a six-week follow-up period. The Part B description says that the blosozumab formulation was determined by Part A and gives the same dosing schedule. The registry record does not explain the allocation process between formulations, how Part B participants were selected, or how the parts related to one another analytically.

The posted primary results list Blosozumab Formulation A, Blosozumab Formulation B, Placebo Formulation A, and Placebo Formulation B. Their listed group sizes are 14, 8, 3, and 3, respectively. The record also labels the study model as single group, although it separately reports randomized allocation, double masking, and results for four groups. That combination of registry labels is not clarified in the record, so the group descriptions are the clearest available account of the reported comparisons.

The brief summary says participation lasted approximately 12 weeks, not including screening, which was required within 28 days before starting the study. The study start is recorded as 2015-01 and primary completion as 2015-03. Further details about the randomization method, masking procedures, dose levels, and the reason the study was terminated 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 at least 1 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 1 dose of study drug.

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 Baseline through Day 85.

The primary endpoint counts participants with one or more serious adverse events that the investigator considered related to study drug administration. The recorded timeframe is baseline through Day 85, and the stated population is all participants who received at least 1 dose of study drug. This is a participant count, not a measure of how many total events occurred: a participant with more than one qualifying event would still be counted as a participant with an event for this endpoint.

Safety and tolerability are central concerns in a Phase 1 multiple-dose study, so a serious-adverse-event endpoint can describe whether serious events judged related to the study drug were observed during the specified period. Investigator attribution is part of the endpoint definition. It means the reported count is not simply a count of every serious event, regardless of cause. The registry description directs readers to the reported adverse-events section for other nonserious adverse events and all serious adverse events, regardless of causality.

The endpoint does not capture every aspect of safety or tolerability. It does not, by itself, describe nonserious symptoms, laboratory findings, pharmacokinetic behavior, or events judged unrelated to treatment. Nor does a participant count quantify event severity beyond the serious-event classification. The posted results show zero participants with a related serious adverse event in each of the four listed groups. Those counts are descriptive observations for the reported study population and timeframe, not proof that the risk of such events is absent.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is this? The primary outcome is binary at the participant level: each participant either met the endpoint definition or did not. The reported statistic is a count of participants, rather than an average score or a count of all event episodes. This distinction matters because repeated qualifying events in one participant do not necessarily increase the number of participants counted for this endpoint. The registry identifies the unit as participants and the parameter as a count of participants.

What does the endpoint definition include? It requires at least one serious adverse event and investigator judgment that the event was related to study drug administration. The timeframe is baseline through Day 85. The analysis population is all participants who received at least 1 dose of study drug. These details define which observations qualify; changing the event definition, causality criterion, timeframe, or population could produce a different count. The record does not provide further operational criteria for seriousness or relatedness.

Why are there no comparative estimates? A comparison between groups for a binary outcome ordinarily depends on the event counts and the numbers of participants at risk in each group. Here, the posted primary count is zero in each listed group, and the record says values are missing or not estimable for a two-arm binary comparison. No comparative estimate or uncertainty interval is posted. It would therefore be inappropriate to turn these counts into a numerical claim about how the groups differ. The record also has no posted analysis entries for the listed outcome measures.

How should uncertainty be understood? General statistical explanation: an estimate from a study is uncertain because the observed participants are only one possible realization of the process being studied. A confidence interval, when reported, expresses a range of values compatible with the data under the assumptions of the statistical method. It is not a guarantee that the true value lies in that range. No confidence interval is reported for this primary endpoint. With zero observed events, the data still do not establish that the underlying event risk is zero; the amount of uncertainty depends in part on the amount of information available and on the analysis method.

What do planning calculations mean? General statistical explanation: sample-size calculations use assumptions about an effect to estimate how many participants per arm a future study might need for a chosen power and significance level. Such values are planning illustrations, not observed results and not evidence that a completed study had a particular probability of detecting an effect. The registry’s stated illustration assumptions refer to a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a fraction of the observed effect. The posted primary endpoint does not have an estimable two-arm effect, so no meaningful planning comparison for this endpoint can be drawn from those assumptions.

What does randomization and masking contribute? General statistical explanation: random allocation is intended to reduce systematic differences between groups at the time of assignment, while masking can reduce the influence of knowledge about assignment on participant or investigator behavior and assessment. The registry labels allocation as randomized and masking as double. It does not report the randomization sequence, concealment method, identities of the masked parties, or whether masking was maintained. Those details cannot be inferred from the labels alone.

How should the formulation groups be read? The posted outcomes keep Formulation A and Formulation B separate, and also distinguish placebo groups labelled Formulation A and Formulation B. This presentation allows readers to see the reported participant counts by listed group without assuming that the formulations were pooled. The record does not provide a prespecified pooling rule or a detailed analysis plan. The Part B description states that its blosozumab formulation was determined by Part A, but it does not explain whether or how Part B data were combined with Part A data in the reported endpoint counts.

What statistical details remain unavailable? The registry record does not report a statistical analysis plan, a method for handling missing observations, an approach to multiplicity, or a rationale for the enrollment target. It does not report interim analyses or adjustments for covariates. These absences limit assessment of how the analysis was planned and whether any potential analytic decisions were made before or after results were known. They should be treated as unreported information, not evidence that a particular method was or was not used.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Blosozumab Formulation A", "Blosozumab Formulation B", "Placebo Formulation A", "Placebo Formulation B")
n      <- c(14, 8, 3, 3)
events <- c(0, 0, 0, 0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Blosozumab Formulation A  14  0  0.0  0.0  23.2  0.0  21.5  0.2  21.8
ARM  Blosozumab Formulation B  8  0  0.0  0.0  36.9  0.0  32.4  0.3  33.6
ARM  Placebo Formulation A  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2
ARM  Placebo Formulation B  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists three secondary pharmacokinetic outcomes: maximum concentration, time to maximum concentration, and area under the concentration-versus-time curve during one dosing interval, each for blosozumab Formulations A and B. The record states four outcome measures, but it does not provide posted analysis entries for these outcomes. Their numerical results, uncertainty estimates, and any comparisons are not reported in the registry record.

Multiplicity arises when several outcomes or comparisons are examined, because the chance of at least one chance-positive result can increase across a collection of tests. General statistical explanation: researchers may address this with a prespecified hierarchy, adjustment, or other strategy, but the appropriate approach depends on the study question and analysis plan. A multiplicity strategy is not reported in the registry record. No adjustment or testing procedure should be assumed.

Handling of missing data is also not reported in the registry record. The primary outcome population is described as all participants who received at least 1 dose of study drug, but the record does not say how participants with incomplete safety follow-up or missing endpoint information were handled. The posted group sizes accompany the endpoint counts, but they do not establish whether every participant completed follow-up or whether any observations were unavailable.

The registry record does not report a statistical analysis plan, interim analyses, or a sample-size justification. It therefore is not possible to determine from the record whether the posted outcomes were designated as primary or secondary before data collection, or how analysis decisions were prespecified. These are reporting limitations; they do not establish that the underlying study lacked such procedures.

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 non-serious adverse event terms

The primary safety measure counts participants with one or more serious adverse events that the investigator considered related to study drug administration. Its timeframe is baseline through Day 85, and its population is participants who received at least 1 dose of study drug. The posted count is zero for Blosozumab Formulation A, zero for Blosozumab Formulation B, zero for Placebo Formulation A, and zero for Placebo Formulation B. The corresponding group sizes are 14, 8, 3, and 3.

These figures refer to participants meeting the endpoint definition, not to all adverse events and not to all serious adverse events regardless of causality. The registry directs readers to the reported adverse-events section for other nonserious events and all serious events, regardless of causality. Its adverse-event summary lists 11, 5, 2, and 0 participants with other adverse events in the same group order. Those figures address a different category and should not be read as counts of related serious events.

A zero observed count is not evidence that an event is impossible or that the true risk is zero. The record does not provide confidence intervals or comparative estimates for these counts. The small group sizes, especially the placebo groups, also mean the observations alone provide limited information about uncommon events. The reason for termination and details of follow-up completeness are not reported in the registry record.

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

The results mean that, in the listed analysis population and during the reported timeframe, no participants in any of the four groups were recorded as having a serious adverse event considered by the investigator to be related to study drug administration. This is a descriptive statement about the observed participants. It is limited to the endpoint definition, the recorded follow-up period, and the groups listed in the registry.

It does not mean that no serious adverse events of any cause occurred. The primary endpoint excludes serious events not considered related to study drug, while the registry says all serious adverse events regardless of causality are reported separately. It also does not mean that no nonserious adverse events occurred: the adverse-event summary lists participants with other adverse events in several groups. The two types of counts answer different safety questions.

The zero counts do not show that the formulations have identical safety profiles, or that one is safer than another. The registry record does not post comparative estimates, confidence intervals, or tests for the binary primary outcome, and it states that values are missing or not estimable for a two-arm comparison. Without those results, the precision of a between-group difference cannot be assessed. In general, a lack of observed events in a study does not establish that an event cannot occur in a larger or different population.

The results also do not answer whether the formulations have similar pharmacokinetics. Although the record lists maximum concentration, time to maximum concentration, and area under the concentration-versus-time curve during one dosing interval as secondary outcomes, their results are not reported in the registry record. Nor do the safety counts explain why the study was terminated, establish the effectiveness of blosozumab, or show what would happen with use beyond the study’s described schedule and follow-up. Those questions are not answered by the posted primary endpoint.

14. Why This Trial Matters Statistically

This study illustrates why safety counts need to be interpreted alongside group sizes, outcome definitions, and uncertainty. The primary result is straightforward to state: the registry records no participants with an investigator-attributed related serious adverse event in any listed group. But a zero count does not, by itself, provide a precise estimate of event risk or a reliable comparison between formulations. The posted record does not include the comparative estimates needed to quantify a difference.

The trial also separates two formulation groups and two placebo-labelled groups rather than presenting a single pooled contrast. That distinction is useful when the question concerns formulation-specific safety, but it makes clear reporting of the planned comparisons important. The record does not explain whether pooling was planned or how the Part B data relate to Part A analyses. It identifies randomized allocation and double masking, yet additional implementation details are not reported.

There is also a difference between registry-level outcome listings and the evidence needed for a full statistical assessment. The record names pharmacokinetic outcomes and gives a primary endpoint population and timeframe, but does not include posted analysis entries for the outcomes. It does not report missing-data methods, multiplicity handling, a statistical analysis plan, or a sample-size rationale. These omissions prevent readers from assessing several aspects of the prespecified analysis and the precision of the results.

For clinical researchers and biostatisticians, the key lesson is that a count of zero is an observation, not a conclusion about absence of risk. Interpreting it requires the denominator, the event definition, the follow-up period, and suitable uncertainty estimates. The registry provides some of those elements, but not the comparative or methodological details needed to draw stronger statistical conclusions.

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 main limitation is the absence of comparative statistics for the primary binary endpoint. Although the registry reports zero qualifying participants in each group, it states that values are missing or not estimable for a two-arm comparison. No effect estimate, confidence interval, or test result is reported. The observed counts therefore support a descriptive account only, not a quantified comparison of formulations or placebo groups.

The group sizes differ, and the placebo groups are each listed with 3 participants. With no reported interval estimates, the precision of the observed counts cannot be directly evaluated from the registry results. Follow-up completeness and the handling of missing endpoint data are not reported. The endpoint is restricted to serious adverse events judged related to study drug, while other adverse events and serious events regardless of causality are reported separately; the primary count should not be treated as a complete description of safety.

Several design and analysis details are also unavailable. The registry identifies randomized allocation and double masking, but does not describe the implementation. It labels the model single group while also listing four outcome groups, and it does not explain that combination. Part B is described as using a formulation determined by Part A, but the record does not describe how the parts were analyzed together or separately. The reason for termination is not reported in the registry record.

The record lists three pharmacokinetic secondary outcomes but does not provide their results or analysis entries. It also does not report multiplicity handling, a missing-data strategy, an analysis plan, interim analyses, or the rationale for the enrollment target. These limitations concern what can be established from the registry record and should not be mistaken for proof that a particular design or analysis procedure was absent from the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of 2 Different Formulations of Blosozumab (LY2541546) in Post Menopausal Women — NCT02337387.
• Registry record last updated 2019-01-22; status last verified 2018-08.
• Results first posted 2019-01-22.
• 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 record describes a randomized, double-blind Phase 1 study of two blosozumab formulations in postmenopausal women. It lists postmenopausal osteoporosis as the condition, enrollment of 28, and terminated status. The treatment descriptions cover Part A and Part B and specify subcutaneous dosing through week 6 followed by a six-week follow-up period; the brief summary describes participation of approximately 12 weeks, not including screening.

The primary endpoint is the participant count for one or more serious adverse events considered by the investigator to be related to study drug administration, from baseline through Day 85, among participants who received at least 1 dose. The posted count is zero in each of the four groups. Comparative values are missing or not estimable for the two-arm binary endpoint. Three pharmacokinetic secondary outcomes are listed, but their results are not reported in the registry record.

The record does not explain the reason for termination or report detailed analysis methods, missing-data handling, multiplicity procedures, or the sample-size rationale. The safety counts are therefore best read as descriptive findings, not as proof of no risk or evidence of a difference between formulations.