A Study of Abemaciclib (LY2835219) In Participants With Previously Treated Breast Cancer That Has Spread: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Abemaciclib (LY2835219) In Participants With Previously Treated Breast Cancer That Has Spread (NCT02102490), a na phase 2 study. The primary outcome is Percentage of Participants With Complete Response (CR) or Partial Response (PR) (Objective Response Rate [ORR]).

2. Clinical Question

3. Trial Design

This was a Phase 2, single-group study of abemaciclib in participants with previously treated metastatic breast cancer. The official title specifies hormone receptor positive, HER2 negative metastatic disease. The registry lists 132 participants enrolled and identifies Eli Lilly and Company as the sponsor. The record lists the study as completed, with a start date of 2014-06-10 and primary completion date of 2016-04-30.

There was one listed intervention, abemaciclib. The regimen was 200 milligrams by mouth every 12 hours for 28 days, with treatment potentially continuing until discontinuation criteria were met. The record does not give further detail about those criteria. Masking is recorded as NONE, and allocation is recorded as NA. The study model is single-group, so the posted design does not include a concurrent comparator.

The primary endpoint was the percentage of participants with a complete or partial response. Its stated assessment period began at first dose and continued until progression or death from any cause, up to 14 months. The endpoint description defines response using RECIST v1.1. The primary analysis population is described as enrolled participants who received at least one dose; the record does not provide a separate analysis count.

Other listed outcomes cover overall survival, duration of response, progression-free survival, disease control, clinical benefit, pain, pharmacokinetics, and quality of life. Nine secondary outcomes are listed. The registry record lists no analyses. It does not report a detailed statistical analysis plan, the planned schedule of outcome assessments, or a sample-size justification for the clinical trial. A separate planning illustration, if considered, should not be mistaken for the design or analysis actually used in this single-group study.

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: In the Participant Flow, participants who completed were those who died due to any cause or were alive and on study at conclusion but off treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All enrolled 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 enrolled participants who received at least one dose of study drug.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With Complete Response (CR) or Partial Response (PR) (Objective Response Rate [ORR]), measured over From Date of First Dose until Disease Progression or Death Due to Any Cause (Up To 14 Months).

The primary endpoint is the objective response rate: the percentage of participants whose best overall response was a complete response or partial response. Complete response means disappearance of all target and non-target lesions with no new lesions. Partial response means at least a 30% decrease in the sum of the longest diameters of target lesions, using the baseline sum as reference, with no progression of non-target lesions and no new lesions.

Response criteria provide a structured way to classify changes in measurable disease. Combining complete and partial responses into one endpoint gives a binary outcome for each participant: either the participant met the response definition or did not. The percentage then describes the share of the specified analysis population meeting that definition. It does not, on its own, describe how long a response lasted; duration of response is listed separately as a secondary outcome.

The endpoint was assessed from first dose until disease progression or death from any cause, up to 14 months. Its stated population includes all enrolled participants who received at least one dose. That population definition matters because a response percentage depends on who is counted in its denominator. The registry record does not report the observed response percentage, its confidence interval, or the number of participants contributing to the primary result. Thus the endpoint's definition is available, but its result cannot be interpreted quantitatively from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary participant-level outcome summarized as a percentage. Each participant in the defined population is classified according to whether their best overall response met the complete or partial response criteria. A percentage is a descriptive summary of the proportion meeting those criteria; it is not a measure of the length of response, the timing of response, or a comparison with an untreated group.

What does the response definition capture?

RECIST v1.1 supplies the response framework named in the registry record. Complete response requires disappearance of target and non-target lesions and no new lesions. Partial response requires at least a 30% decrease in the sum of the longest diameters of target lesions relative to the baseline sum, alongside no progression of non-target lesions and no new lesions. These rules make the classification depend on both changes in target lesions and the status of non-target or new lesions. A change that does not meet either response definition is not counted as an objective response, even though other categories, such as stable disease, may be relevant to secondary outcomes.

Best overall response is the basis of the primary classification. The stated timeframe runs from first dose until progression or death from any cause, up to 14 months. This defines the period over which the response outcome was to be assessed; it does not supply the observed response data or establish how often assessments occurred. Assessment schedules and further implementation details are not reported in the registry record.

How should a percentage and confidence interval be read?

In general, the percentage is an estimate of the response frequency in the analysis population. A confidence interval communicates uncertainty around that estimate under the method used. It is not a guarantee that a particular range contains the true value, and its interpretation depends on the statistical assumptions and analysis procedure. The record specifies a 95% confidence interval as the endpoint's dispersion measure, but does not report the interval itself or identify a detailed method for calculating it. It is therefore not possible to assess precision or reproduce the primary analysis from the registry record.

Binary outcomes commonly involve sampling uncertainty because the participants enrolled in a study are not every possible participant to whom the question might be relevant. General statistical methods quantify that uncertainty using the observed outcome count and denominator. Those inputs are not reported for the primary endpoint. The enrollment count alone cannot be used to recover the response estimate, because the number of responders is absent and the primary analysis population may differ from total enrollment under the stated eligibility for analysis.

What does the single-group design allow?

The trial is recorded as single-group and lists abemaciclib as its intervention. In general, a single-group response percentage describes outcomes within the treated group. It can be useful as a description of observed activity, but it does not provide a randomized treatment contrast. Randomization and a comparator help make groups comparable for estimating differences; no such comparison is described in this record. The result, even if reported, would need to be interpreted as an outcome frequency in the study group rather than a direct estimate of the difference caused by treatment.

Masking is recorded as NONE. In general, masking can reduce the influence of knowledge of treatment assignment on some aspects of trial conduct or assessment. The record does not give additional detail about how response assessments were conducted or whether any independent review was used, so those procedures cannot be characterized further.

What are planning illustrations?

General sample-size calculations can illustrate how many participants per arm might be needed for a hypothetical comparison under specified assumptions. The stated assumptions for any planning illustration use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of the observed effect. Those assumptions do not describe this single-group study's design. The illustrations are planning exercises, not observed power, and should not be read as evidence that the trial was designed or analyzed using a two-arm comparison. The registry record does not report its own sample-size justification.

More broadly, statistical interpretation depends on the analysis population, endpoint definition, missing-data handling, and analysis method. The record gives the primary population definition and endpoint criteria but does not report the primary estimate, analysis count, analysis details, or missing-data procedures. The planned statistical analysis is not reported in the registry record. These omissions prevent a fuller assessment of reproducibility and precision, regardless of the clarity of the endpoint definition.

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("Abemaciclib")
n      <- c(132)
events <- c(26)
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  Abemaciclib  132  26  19.7  13.3  27.5  13.8  27.3  13.8  27.3

11. Multiplicity, Missing Data and Analysis Populations

The record lists one primary outcome and nine secondary outcomes. The secondary outcomes include overall survival, duration of response, progression-free survival, disease control rate, clinical benefit rate, pain, pharmacokinetic measures, and quality-of-life change. Considering multiple outcomes raises a general multiplicity question: when many statistical questions are examined, the chance of at least one apparently notable result can increase unless the analysis approach accounts for the number and relationship of those questions. Whether or how that issue was handled in this study is not reported in the registry record. No adjustment method, testing hierarchy, or distinction between confirmatory and exploratory secondary analyses is described.

The record lists no analyses. It does not report a statistical analysis plan, interim analyses, or procedures for deciding which outcomes or populations would be included in each analysis. These details should not be inferred from the outcome list or from the primary endpoint definition. The listing of an outcome indicates that it was specified as an outcome, not that its analysis or result is available.

Missing-data procedures are not reported in the registry record. The primary endpoint population is defined as all enrolled participants who received at least one dose, but the record does not say how participants without an evaluable response, participants who discontinued, or incomplete assessments were handled. It also does not report the number analyzed for the primary endpoint. Without these details, the relationship between total enrollment and the endpoint denominator cannot be assessed.

In general, missing outcome information can affect an estimate if participants without observed assessments differ from those with assessments. Statistical methods may address missingness under stated assumptions, but the assumptions and procedures need to be known to evaluate their implications. No such method or assumption is described. The appropriate conclusion is not that data were missing or mishandled, but that the registry record does not report how missing data were addressed.

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: nausea (2.3%), blood creatinine increased (2.3%), dehydration (2.3%), abdominal pain (1.5%), cellulitis (1.5%).

The registry safety summary lists 132 participants at risk for serious adverse events, with 33 participants affected. It also lists 132 participants at risk in the other adverse-event group, with 132 affected. These are participant counts in the registry's safety categories; they are not counts of individual event episodes, and the categories should not be treated as a comparison between treatment groups. The study lists only one intervention group.

The serious adverse-event terms and their recorded percentages include nausea, 2.3%; blood creatinine increased, 2.3%; dehydration, 2.3%; abdominal pain, 1.5%; cellulitis, 1.5%; and dyspnoea, 1.5%. These entries describe the listed terms and percentages, not the primary efficacy endpoint. The registry record does not provide further detail about event timing, duration, severity beyond the serious-event classification, or whether each event was judged related to study treatment. The counts alone should not be interpreted as establishing causation.

Safety data and response data answer different questions. The safety counts describe reported adverse events in the study group; they do not indicate how many participants met the objective response definition. Because no comparator group is listed, the safety summary also does not provide a controlled estimate of excess risk relative to another treatment. The record's categories and denominators should be kept distinct when reading the figures.

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

The registry record identifies a Phase 2 study intended to evaluate abemaciclib in participants with previously treated metastatic breast cancer. It specifies a primary objective response endpoint based on RECIST v1.1, a treatment regimen, and a population definition. Those details explain what the study set out to assess, but they are not a substitute for the primary result.

The objective response percentage and 95% confidence interval are not reported in the registry record. Therefore, the posted data do not establish how many participants had a complete or partial response, how frequent such responses were in the analysis population, or how precisely that frequency was estimated. The record also lists secondary outcomes without reporting their numerical results. No interpretation of those outcomes as observed findings is possible from the information recorded.

Even when a single-group response estimate is available, it describes the outcome in that study group rather than a randomized difference between treatments. With no comparator group listed, the design cannot separate the group's observed outcomes from other influences through a controlled comparison. That distinction is especially important when readers want to make claims about comparative effectiveness or causality.

The safety summary reports adverse-event counts and several serious-event terms, but these do not answer the efficacy question. The record does not give details needed to assess event attribution or compare safety with another group. Likewise, total enrollment is not evidence of response, and the number enrolled cannot replace a reported endpoint estimate.

The most defensible interpretation is narrow: the registry describes the study's intervention, response definition, and intended assessment period, while the primary efficacy result and statistical analysis details are absent. The study's status is listed as completed, but completion status does not itself reveal the study's clinical findings. Readers should distinguish the existence of a registered study and its stated outcomes from the availability of results for those outcomes.

14. Why This Trial Matters Statistically

This trial illustrates why a clear endpoint definition and a reported endpoint result are both necessary for statistical interpretation. The registry gives a detailed description of objective response, including the RECIST v1.1 criteria for complete and partial response, and states the population and assessment timeframe. Those elements make the intended measurement understandable. However, without the observed percentage, response count, and confidence interval, the central estimate and its precision cannot be evaluated.

The single-group design also clarifies the boundary between describing outcomes and comparing treatments. A response rate within one treatment group may characterize what was observed among participants in that study, but it does not by itself estimate a contrast against another treatment. The record's allocation and masking entries, together with the single-group model, make it important not to read a comparison into the design.

The registry also shows the importance of transparent analysis reporting. Nine secondary outcomes are listed, but no analyses are recorded. Information about multiplicity, missing data, analysis populations beyond the stated primary population, and statistical methods is not reported in the registry record. These details affect how readers assess credibility, precision, and the scope of conclusions.

Finally, the listed safety counts and terms should be read as safety information, not as a substitute for efficacy findings. Keeping design, endpoint definitions, observed results, and safety summaries conceptually separate is central to sound clinical-trial interpretation. In this record, the design and endpoint are described, while the primary numerical result needed for a statistical assessment is not reported.

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 for statistical interpretation is that the registry record does not report the primary objective response result. It gives neither the response percentage nor its 95% confidence interval, and it does not state the primary analysis count. This prevents evaluation of the observed response frequency and its precision.

The single-group design has no listed comparator, so the study cannot provide a randomized, like-for-like treatment comparison. The record also marks masking as NONE. It does not give further details about response assessment procedures, including whether assessment was independently reviewed. These design features limit what can be concluded about comparative outcomes and how assessment was implemented.

Although nine secondary outcomes are listed, the record contains no analyses or numerical secondary results. Multiplicity handling, missing-data methods, interim analyses, and a detailed statistical analysis plan are not reported in the registry record. The primary population is defined as enrolled participants who received at least one dose, but no primary analysis denominator or evaluability information is reported. The record does not explain how incomplete response assessments or discontinuations were handled.

The safety summary provides counts and selected serious adverse-event terms, but does not report further detail about event timing or treatment attribution. The study regimen is described, but discontinuation criteria are not specified. These limitations are specific to information available in the registry record; they do not establish that the omitted procedures or data were absent from the study, only that they are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of Abemaciclib (LY2835219) In Participants With Previously Treated Breast Cancer That Has Spread — NCT02102490.
• Registry record last updated 2020-01-21; status last verified 2020-01.
• Results first posted 2017-11-30.
• 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

NCT02102490 is a completed Phase 2, single-group study sponsored by Eli Lilly and Company. The registry lists 132 participants enrolled and abemaciclib as the intervention, given orally at 200 milligrams every 12 hours for 28 days, with treatment potentially continuing until discontinuation criteria were met. The listed population is participants with previously treated hormone receptor positive, HER2 negative metastatic breast cancer.

The primary endpoint is the percentage of participants with complete or partial response under RECIST v1.1, assessed from first dose until progression or death from any cause, up to 14 months. The primary population is enrolled participants who received at least one dose. The objective response result and 95% confidence interval are not reported in the registry record. Nine secondary outcomes are listed, but the registry record lists no analyses. Safety counts and selected serious adverse-event terms are recorded, without a comparator group.