A Phase 2 Study of Lenalidomide to Evaluate the Efficacy in Japanese Patients With Newly Diagnosed Multiple Myeloma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Phase 2 Study of Lenalidomide to Evaluate the Efficacy in Japanese Patients With Newly Diagnosed Multiple Myeloma (NCT01698801), a na phase 2 study. The primary outcome is Overall Response Rate.

2. Clinical Question

In practical terms, this trial was designed to describe response in a specified population receiving a two-drug regimen, rather than to estimate a treatment difference against another therapy or usual care. The response definition combines several levels of tumor response into one binary classification: each participant is counted as a responder if any qualifying response occurred while on study treatment, and otherwise is not counted as a responder. The record identifies time to response, duration of response, progression-free survival, overall survival, and adverse events among the secondary outcomes. Those outcomes add different dimensions of follow-up, but the central question remains the proportion of the efficacy evaluable population meeting the response criteria. The registry record does not state a separate comparator-based primary question, and it does not give the observed overall response rate.

3. Trial Design

This was a Phase 2, multicenter, open-label, single-arm study of lenalidomide in combination with low-dose dexamethasone in Japanese participants with previously untreated multiple myeloma. The registry record lists allocation as not applicable, masking as none, and the study model as a single group. It reports enrollment of 26 participants and a completed status. The listed study start was 2012-10-01, and primary completion was 2013-11-26.

In a single-group design, participants receive the study regimen without a concurrent randomized control group. The study can describe outcomes observed among participants receiving the regimen, but it does not directly estimate how those outcomes differ from outcomes under another treatment. Without a concurrent comparison group, differences from an external benchmark may reflect differences in participant characteristics, follow-up, eligibility, or outcome assessment as well as any treatment-related effects. This is a general design consideration, not a claim about what occurred in this study.

The open-label designation means masking was not used, as reflected in the registry record. The record does not report the number of participating centers, details of treatment duration, or the schedule and procedures for outcome assessment beyond the primary endpoint timeframe. It also does not report a comparator arm, randomization procedure, or a rationale for the enrollment target. These details should not be inferred from the Phase 2 designation or from the study title.

The registry record describes the primary endpoint population as the efficacy evaluable population: participants who met protocol requirements, including eligibility criteria, and were evaluated after receiving at least one dose of study drug. That definition is narrower than simply naming all enrolled participants, but the record does not state how many of the 26 enrolled participants met the definition. Safety event counts use 26 participants at risk. The difference in stated populations matters when reading estimates: an endpoint percentage ordinarily depends on its analyzed denominator, and the registry record does not report the denominator or the endpoint result for overall response.

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: This is an ongoing open-label, single arm, 5 year study consisting of a 28-day screening period followed by a treatment period where participants receive lenalidomide and dexamethasone until their disease progresses or the lenalidomide is discontinued for any reason. This report includes data up to the cut-off of 15 July 2014.

Treatment Phase

Reasons for not completing this period:

Follow Up Phase

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Efficacy Evaluable (EE) Population consists of all participants who met the protocol requirements (all eligibility criteria) and were evaluated after receiving 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: The intent-to-treat (ITT) population consisted of all participants enrolled independent of whether they received study treatment or not.

6. Primary Endpoint

The registry lists the primary outcome as Overall Response Rate, measured over From first dose until the data cut-off date of 15 July 2014. Median time on follow-up was 61.6 weeks..

The primary endpoint was overall response rate, expressed as a percentage of participants. It was defined by the number of participants achieving complete response, very good partial response, or partial response based on International Myeloma Working Group criteria. A participant was a responder if a qualifying response occurred while the participant was receiving study treatment. The timeframe ran from the first dose through the data cut-off date of 15 July 2014; the reported median time on follow-up was 61.6 weeks.

The response categories represent different degrees and forms of change in disease findings. Complete response required negative serum and urine results on immunofixation, disappearance of any soft tissue plasmacytomas, and no more than 5% plasma cells in bone marrow. Very good partial response included M-protein detectable by immunofixation but not electrophoresis, or a reduction of at least 90% in serum M-protein with urine M-protein below 100 mg/24 hours. Partial response required a reduction of at least 50% in serum M-protein and a reduction in urinary M-protein of at least 90% or to below 200 mg/24 hours. When soft tissue plasmacytomas were present at baseline, the criteria also required their size to decrease by at least 50%.

Combining these categories into one binary endpoint gives a concise summary of whether participants crossed a predefined response threshold. This is a general reason for using a composite response endpoint; it does not mean that all qualifying responses are equally deep or durable. The response count and percentage are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary participant-level endpoint: each participant either met the response definition or did not. The underlying clinical criteria classify complete response, very good partial response, and partial response; the overall response endpoint groups all three categories together. This is distinct from an outcome that measures the degree of change on a continuous scale. It also differs from a time-to-event outcome, which incorporates both the timing of an event and follow-up information.

As a general statistical explanation, a response percentage is calculated from the number of responders relative to the number of participants evaluated for that endpoint. The estimate is meaningful only when its numerator and denominator are clear. The registry record defines the efficacy evaluable population but does not report its size, the number of responders, or the response percentage. Therefore, the primary endpoint cannot be numerically interpreted or recalculated from the registry information. Enrollment of 26 is not a replacement for the endpoint denominator when the endpoint population is separately defined.

As a general explanation, uncertainty around a binary estimate is often described with a confidence interval. The interval expresses sampling uncertainty under a statistical method and assumptions; it is not a guarantee that a future study will produce a result inside its limits. No confidence interval or method for calculating one is reported for the primary response result in the registry record. The registry record also does not report a hypothesis test or a statistical model for that endpoint. Without the response count and denominator, there is no basis for independently recalculating an estimate or its uncertainty.

The study's primary endpoint is not a direct between-group contrast because the design has one treatment group. General methods for estimating treatment differences in randomized studies rely on outcomes from both groups and a defined comparison. That structure is absent. The registry record gives allocation as not applicable and identifies a single-group model; it does not report a treatment-effect estimate against a control. Consequently, the relevant descriptive quantity would be the response proportion within the efficacy evaluable population, if that result were reported, rather than a relative or absolute treatment difference.

The study record lists one analysis and six outcome measures. This information does not, by itself, describe the complete statistical analysis plan. The statistical methods for the primary endpoint, handling of missing outcome data, and any prespecified hypothesis are not reported in the registry record. It would be inappropriate to infer a particular model, confidence-interval method, test, or missing-data rule from the endpoint label alone.

Planning calculations require a different interpretation from observed results. The sample-size assumptions described for the 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. For time-to-event outcomes, the stated planning quantity is total events; for other outcomes, it is participants per arm. These are planning assumptions, not a description of this trial's single-group design. The registry record does not state that those assumptions were used to design the study, and no sample-size justification is reported in the registry record.

As a general statistical explanation, a planning calculation asks how much information might be needed under specified assumptions to detect a target effect. Its output depends on those assumptions and is not an observed result. A planning illustration based on an observed effect should not be treated as evidence that a study had a particular level of power after the results were known. It is not observed power, and it does not replace the response estimate, denominator, or uncertainty interval. The registry record does not report the study's own sample-size justification or design assumptions, so the planning illustration should not be used to infer the protocol's rationale.

For time-to-event outcomes such as duration of response, progression-free survival, or overall survival, general analysis methods account for differing follow-up and censoring: participants may have follow-up that ends before an event is observed. The registry record lists these outcomes, but the particular estimands, censoring rules, analysis methods, event counts, and numerical results are not reported in the information. No time-to-event result or model should be inferred from the outcome names alone.

Over-dispersion is a general concern when observed variability exceeds what a simple statistical model assumes. It can make standard errors too small and confidence intervals too narrow if ignored. That issue does not establish that over-dispersion occurred in this trial; the registry record does not describe a model for the primary binary endpoint or report any over-dispersion assessment. The core methodological reading is therefore restrained: the endpoint is defined, the trial design is single-group, and the numerical response result and its statistical uncertainty are not reported in the registry record.

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("Lenalidomide Plus Dexamethasone")
n      <- c(24)
events <- c(21)
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  Lenalidomide Plus Dexamethasone  24  21  87.5  67.6  97.3  69.0  95.7  68.8  95.5

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists overall response rate as the primary outcome and identifies Time to Response, Duration of Response, Progression Free Survival (PFS), Overall Survival (OS), and Number of Participants With Adverse Events as secondary outcomes. It reports six outcome measures and one analysis. The presence of multiple outcomes raises a general statistical question about multiplicity: when several hypotheses are tested, the chance of at least one apparently positive result can increase if no adjustment or prespecified hierarchy is used. The registry record does not report a multiplicity adjustment, testing hierarchy, or other plan for interpreting multiple outcome tests. It also does not report the primary-endpoint hypothesis test or p-value.

The registry record defines the efficacy evaluable population as participants meeting protocol requirements and evaluated after at least one dose. It does not report the number in that population or explain how participants with missing response assessments were handled. The record does not state whether missing outcomes were excluded, classified in a particular way, imputed, or addressed through a sensitivity analysis. Those procedures are not reported in the registry record, and none should be assumed.

As a general statistical principle, missing outcome data can affect both the analysis denominator and the interpretation of an estimate, particularly if the chance of a missing assessment is related to participants' outcomes. Clear reporting of the analysis population and missing-data handling helps readers understand which participants contributed to a result and how robust it may be. Here, the primary response numerator and denominator are not reported, preventing that assessment.

The record's efficacy evaluable definition is not enough to determine how it was implemented, and the enrollment count should not be substituted for an unreported endpoint population count. Safety summaries refer to 26 participants at risk, but that safety denominator does not establish the efficacy denominator. Statistical analysis details, reasons for exclusion from the efficacy evaluable population, and methods for handling missing data are not reported in the registry record.

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: cardiac failure acute (3.8%), coronary artery stenosis (3.8%), pneumonia (3.8%), urinary tract infection (3.8%), interstitial lung disease (3.8%).

The registry record reports 26 participants at risk for serious adverse events and 11 participants affected. It also reports 26 participants at risk for other adverse events and 26 affected. These are separate safety summaries; they do not provide a comparison with a control group. The registry record does not report a number of deaths in the safety summary.

Six serious adverse event terms are listed, each with a reported frequency of 3.8%: CARDIAC FAILURE ACUTE, CORONARY ARTERY STENOSIS, PNEUMONIA, URINARY TRACT INFECTION, INTERSTITIAL LUNG DISEASE, and PNEUMONIA ASPIRATION. These term-level figures should be read as the registry's reported frequencies, not as a complete description of severity, timing, duration, or outcome. The record does not give additional clinical detail about these events in the information.

As a general statistical point, participant counts and event-term frequencies answer different questions. A participant may experience more than one event, so counts for individual event types need not represent distinct people or add up to the number of participants affected. The record does not provide enough detail to establish overlap among the listed terms. These safety counts describe events recorded during the study; without a comparison group they do not estimate an excess risk relative to another treatment.

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

This study establishes a registry record for a Phase 2, open-label, single-group evaluation of lenalidomide plus low-dose dexamethasone in Japanese participants with previously untreated multiple myeloma. The primary endpoint was defined as the percentage of the efficacy evaluable population achieving complete response, very good partial response, or partial response under International Myeloma Working Group criteria. The record also specifies the primary endpoint timeframe and reports median follow-up of 61.6 weeks.

The central limitation for interpreting efficacy is that the registry record does not report the primary endpoint's response count, percentage, or denominator. It therefore does not support a statement about the magnitude or precision of the observed overall response rate. Nor does it report a confidence interval or primary-endpoint test in the information. No result should be inferred from the study title, its Phase 2 designation, the enrollment count, or the stated response criteria.

Even with a reported response percentage, a single-group study would describe outcomes among the participants evaluated under the study conditions rather than provide a randomized comparison with another regimen. As a general statistical point, an observed outcome in one group cannot by itself distinguish treatment effects from other explanations for the outcome. The registry record does not report a comparator group or a causal contrast.

The record's safety summary reports 11 participants affected by serious adverse events among 26 at risk, and 26 participants affected by other adverse events among 26 at risk. It lists six serious event terms at 3.8% each. These observations describe the recorded safety experience, but they do not quantify differences from a control group. The record does not report a death count in the safety summary.

The registry entry also names several secondary outcomes, but their numerical results and analysis details are not reported in the information. The study can therefore be characterized by its design, endpoint definitions, follow-up description, and recorded safety counts. It cannot be characterized from this record as establishing a comparative treatment effect, the size of the primary response estimate, or the precision of that estimate. These distinctions separate what the registry documents from what remains unreported.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how design determines the questions that can be answered. A single-group study can describe outcomes among participants receiving a regimen, but its structure does not support a concurrent randomized comparison. The registry record identifies the single-group model, the absence of masking, and allocation as not applicable. Those design details constrain interpretation independently of the clinical endpoint definition.

The primary outcome also illustrates the importance of distinguishing an endpoint definition from an endpoint result. The registry record describes the response categories and the efficacy evaluable population in detail, making clear what would count as a responder. Yet it does not report the responder count, response percentage, or efficacy denominator. Detailed criteria cannot substitute for the observed data needed to estimate the endpoint.

As a general statistical lesson, a point estimate and its precision are both important. A confidence interval can communicate uncertainty around an estimate, while an analysis population and denominator show which observations contributed. In this record, the response estimate and interval are not reported, and the size of the efficacy evaluable population is not stated. This limits both numerical interpretation and independent checking.

The study also helps distinguish descriptive safety information from comparative safety evidence. Counts of participants affected and event-term frequencies can describe what was recorded in the treated group. Without a concurrent control group, they do not quantify a relative increase or decrease in events. The registry record's safety counts should therefore be read as descriptive observations.

Finally, planning calculations and trial design assumptions need to be kept separate. A sample-size planning illustration uses assumptions for a hypothetical calculation; it does not show what the protocol actually used or establish observed power. The registry record does not report the trial's own sample-size justification. Together, these features make the study a useful case for careful attention to endpoint reporting, population definitions, uncertainty, and the limits of single-group evidence.

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 most consequential limitation for interpreting the primary endpoint is the absence of its observed result in the registry record. The response numerator, percentage, and efficacy evaluable denominator are not reported. The record defines the efficacy evaluable population, but does not state how many enrolled participants met that definition or how many had evaluable response assessments. As a result, neither the overall response estimate nor its precision can be assessed from the information.

The single-group design also limits interpretation. There is no concurrent control group, and the registry record lists allocation as not applicable. Outcomes in the treatment group therefore cannot be directly contrasted with outcomes under another intervention within this trial. The open-label design is recorded as having no masking; the record does not describe any additional procedures for reducing assessment bias.

The registry record gives the primary endpoint timeframe through the data cut-off date of 15 July 2014 and reports median follow-up of 61.6 weeks. It does not report the primary result or the timing and completeness of individual response assessments in the information. The record lists secondary outcomes, but their numerical results and analysis details are not reported in the registry record used for this analysis.

Analysis methods are incompletely described for purposes of statistical interpretation. The registry record does not report the primary-endpoint test, interval method, handling of missing response data, multiplicity plan, or the study's sample-size justification. It also does not report the number of participants in the efficacy evaluable population. These gaps should not be filled by assumptions based on common practice or the study phase.

Safety information is descriptive and lacks a concurrent comparison group. Although the registry record reports participants affected and serious event terms, it does not provide event narratives, overlap among event categories, or a death count in the safety summary. These limitations restrict interpretation to the reported counts and definitions rather than comparative safety conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Phase 2 Study of Lenalidomide to Evaluate the Efficacy in Japanese Patients With Newly Diagnosed Multiple Myeloma — NCT01698801.
• Registry record last updated 2018-11-08; status last verified 2018-10.
• Results first posted 2014-12-03.
• 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 completed Phase 2, multicenter, open-label, single-group study of lenalidomide plus low-dose dexamethasone in Japanese participants with previously untreated multiple myeloma. It reports enrollment of 26 participants, a study start of 2012-10-01, and primary completion on 2013-11-26.

Overall response rate was the primary endpoint, defined by complete response, very good partial response, or partial response under International Myeloma Working Group criteria. The endpoint timeframe extended from first dose through the data cut-off date of 15 July 2014; median follow-up was 61.6 weeks. The efficacy evaluable population was defined, but its size and the observed response count and percentage are not reported in the registry record.

The safety record reports 11 participants with serious adverse events among 26 at risk and 26 participants with other adverse events among 26 at risk. Six serious event terms are each reported at 3.8%. The registry record does not provide a concurrent comparator or a death count in the safety summary.