CPX-351 for the Treatment of Secondary Acute Myeloid Leukemia in Patients Younger Than 60 Years Old: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CPX-351 for the Treatment of Secondary Acute Myeloid Leukemia in Patients Younger Than 60 Years Old (NCT04269213), a na phase 2 study. The primary outcome is Complete Response Rate (Morphological Complete Remission [CR] and Incomplete Blood Count Recovery [CRi]).

2. Clinical Question

The study addresses a response question within a defined clinical population rather than a comparative efficacy question. Its listed primary endpoint combines CR and CRi, and the endpoint description says response is defined by the International Working Group Criteria. Combining the two response categories makes the primary outcome a single binary classification for each evaluable patient: meeting the combined response definition or not meeting it. The registry record does not report the separate numbers in CR and CRi, or the combined response result.

The study also lists duration of CR plus CRi, event-free survival, overall survival, allogeneic hematopoietic cell transplant rate, and incidence of adverse events as secondary outcomes. These address different aspects of outcomes and safety, but the registry record does not provide their numerical results in the record summarized for this analysis. With no separate comparator group, the study can describe outcomes among the treated group, but it cannot establish a treatment contrast against an untreated or alternative-treatment group.

3. Trial Design

This is a phase II study of CPX-351 in younger patients with secondary acute myeloid leukemia. The registry record lists 21 participants enrolled, a single-group model, allocation as not applicable, and no masking. The study status is completed. Its recorded start date is 2021-07-29, and its primary completion date is 2025-05-27. The sponsor listed in the record is Roswell Park Cancer Institute.

The single-group design means that participants are described as receiving the study treatment without a separate randomized control group listed in the record. The intervention is liposome-encapsulated daunorubicin-cytarabine. The record describes induction and re-induction in its treatment-arm description, but the complete dosing description is not reported in the registry record. Details such as treatment duration, any additional treatment, or the decision rules for individual treatment are not inferred.

The primary outcome is a count of participants meeting the combined CR and CRi response definition at day 45. The endpoint description says that 19 patients were evaluable for disease response, fewer than the total enrollment. Why two enrolled patients were not evaluable, and how patients were handled in the response analysis, are not reported in the registry record. The stated summary approach is to use frequencies and relative frequencies.

The record lists six outcome measures and no analysis records. Besides the primary response outcome, the named secondary outcomes are CR plus CRi duration, event-free survival, overall survival, allogeneic hematopoietic cell transplant rate, and incidence of adverse events. The record does not report a sample-size justification, a detailed statistical analysis plan, or interim analyses. It also does not report an external or historical control as part of the design. Consequently, the design supports describing the observed single-group outcomes, but not attributing a difference in outcomes to CPX-351 relative to another treatment.

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

Analysis population for the primary outcome, as defined in the registry: 19 patients were evaluable for the disease response.

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.

6. Primary Endpoint

The registry lists the primary outcome as Complete Response Rate (Morphological Complete Remission [CR] and Incomplete Blood Count Recovery [CRi]), measured over At day 45.

The primary endpoint is the number of participants with a complete response, defined as morphological complete remission (CR) or incomplete blood count recovery (CRi), assessed at day 45. The registry says that response is defined by the International Working Group Criteria and that the measure will be summarized using frequencies and relative frequencies. It identifies 19 patients as evaluable for disease response.

A binary response endpoint is used to classify each evaluable participant according to whether the stated response definition is met by the specified assessment time. A frequency gives the number in each response category; a relative frequency expresses that count in relation to the analysis population. General statistical context: a proportion is often a direct and understandable summary for a binary endpoint, while its precision depends on the number of participants assessed and the number meeting the definition. A confidence interval, when reported, conveys a range of values compatible with the data under the method used; it does not remove uncertainty or establish a causal treatment effect.

The registry record does not report the number of patients who achieved CR, CRi, or the combined endpoint, nor does it report a response rate or confidence interval. It therefore does not permit an estimate of the observed response frequency from the endpoint description alone. The reason that 19 patients were evaluable, rather than all 21 enrolled, is not reported in the registry record. No conclusion about the response endpoint should be based on the enrollment count alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a participant count, with each evaluable patient classified according to a combined response definition: morphological complete remission (CR) or incomplete blood count recovery (CRi) at day 45. The registry describes the criterion as based on International Working Group Criteria and says the outcome will be summarized using frequencies and relative frequencies. It does not report the actual response count or relative frequency.

What does a frequency summary mean?

General statistical context: a frequency is a count in a category. For a binary outcome, the categories can be described as meeting or not meeting the response definition. A relative frequency places a category count in relation to the number assessed, expressing how common that category was in the analysis population. Interpretation depends on identifying that population and denominator. Here, the record says 19 patients were evaluable for disease response, but does not report the number with CR, CRi, or the combined response. It also does not explain why the evaluable count is smaller than enrollment.

A count and a proportion are descriptive summaries. They do not, by themselves, describe the uncertainty around the proportion. General statistical context: a confidence interval is an interval estimate intended to communicate uncertainty around an estimated quantity under its statistical assumptions. Its width is affected by the information in the data and the method used. A confidence interval is not the probability that a fixed true value lies inside the particular interval, and it does not establish that an observed result is clinically important. No confidence interval for the primary response endpoint is reported in the registry record.

Why does the study structure matter?

The trial is listed as phase II, single-group, with allocation not applicable and no masking. General statistical context: random allocation to multiple groups can help make groups comparable on average, while a single-group study has no concurrent randomized comparator to support that kind of between-group contrast. In a single-group study, outcome summaries describe the participants observed under the study treatment. Other influences on outcomes cannot be separated from the treatment effect using a within-group result alone. The record does not identify a control group or a comparative primary analysis.

The record also lists no analysis records. That does not establish which procedures were or were not used outside the registry entry; it means that the analysis details are not reported in the registry record. The record does not specify a hypothesis test for the primary endpoint, an interval-estimation method, covariate adjustment, an interim analysis, or a detailed statistical analysis plan. These methods should not be inferred from the phase designation or from the fact that the endpoint is a frequency.

What does evaluability imply?

The registry identifies 21 enrolled participants and 19 patients evaluable for the primary response outcome. General statistical context: an analysis population is the set of participants whose data enter a particular outcome calculation. The choice of population and the handling of absent assessments can affect the estimate. A count of evaluable participants is not automatically equivalent to an intention-to-treat analysis, and the record does not describe the analysis population by that label. It also does not describe how unavailable day-45 assessments were handled. Reasons for non-evaluability, missing-data methods, and any sensitivity analyses are not reported in the registry record.

In general, missing outcome data can create uncertainty about the observed response proportion, especially if the probability of having an observed assessment is related to the outcome. This is a general consideration, not a claim about why data are missing in this study. The registry information does not support assumptions about the two patients outside the stated evaluable population. They should not be counted as responders or nonresponders without a reported analysis rule and data.

How should secondary outcomes be considered?

The registry names CR plus CRi duration, event-free survival, overall survival, allogeneic hematopoietic cell transplant rate, and incidence of adverse events as secondary outcomes. These outcomes have different data structures. General statistical context: a duration or survival outcome typically concerns the time until an event, and interpretation may depend on how events, censoring, and follow-up are defined. A rate or proportion outcome requires an explicit numerator, denominator, and assessment window. The outcome names do not supply these definitions, and further operational details are not reported in the registry record.

Multiplicity is a general concern when several outcomes or analyses are considered: the chance of at least one apparently unusual result can increase when many statistical tests are conducted. The registry record lists six outcome measures and no analysis records, but does not report the number of tests, a hierarchy of hypotheses, or a multiplicity adjustment. It would therefore be inappropriate to claim that a particular adjustment was or was not applied. The planned summary of the primary measure using frequencies and relative frequencies is stated; additional inferential procedures are not.

Finally, statistical significance, if it were reported, would not alone establish the size, precision, or causal meaning of an effect. General statistical context: effect estimates describe magnitude, intervals describe uncertainty under a specified method, and design informs whether a causal comparison is supported. In this record, the primary response estimate and associated uncertainty are not reported, and the design is single-group. The available information therefore supports methodological interpretation of the endpoint and design, not reconstruction of an unreported analysis.

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("Treatment (CPX-351)")
n      <- c(19)
events <- c(8)
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  Treatment (CPX-351)  19  8  42.1  20.3  66.5  23.1  63.7  23.1  63.9

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists six outcome measures: the primary CR plus CRi response outcome and secondary outcomes covering response duration, event-free survival, overall survival, transplantation, and adverse events. It reports no analysis records. A list of outcomes does not reveal how many statistical tests were performed, whether outcomes were ranked in a hierarchy, or whether an adjustment for multiple comparisons was planned. Those details are not reported in the registry record.

General statistical context: when many outcomes or hypotheses are examined, the chance of finding at least one result that appears notable by chance can increase. Approaches to multiplicity can include prioritizing a primary hypothesis, adjusting thresholds, or treating secondary findings as exploratory. This explains why a reported analysis plan is useful; it does not indicate which approach was used in this study. No multiplicity method is reported in the registry record, so none should be assumed.

The primary outcome description identifies 19 patients evaluable for disease response, while 21 participants were enrolled. The record does not state why two participants were not evaluable, whether outcome information was missing, or how any missing observations were handled. It does not report imputation, sensitivity analyses, or an alternative analysis population. General statistical context: exclusions or missing outcomes can affect both the denominator and interpretation of a response estimate, and a missing-data method relies on assumptions that should be stated. The record does not provide a basis for judging those assumptions.

The registry states the outcome assessment time as day 45, but does not report the response count or rate at that time. It also does not report confidence intervals or a detailed analysis plan. Thus, the record permits identification of the intended endpoint and the stated evaluable population, but not verification of the analysis population, missing-data handling, or multiplicity procedures.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: febrile neutropenia (14.3%), fever (9.5%), lung infection (9.5%), sepsis (9.5%), skin infection (4.8%).

For the CPX-351 treatment group, the registry lists 21 participants at risk for serious adverse events and 10 affected; it lists 21 at risk for other adverse events and 20 affected. The record also lists 13 deaths. These entries describe participant counts, not necessarily event counts: an individual may experience more than one event, and the figures do not establish whether the serious-event and other-event categories include the same people. The registry information does not report the event timing or provide a basis to attribute deaths to treatment.

The listed serious adverse event terms and percentages are febrile neutropenia, 14.3%; fever, 9.5%; lung infection, 9.5%; sepsis, 9.5%; skin infection, 4.8%; and postoperative hemorrhage, 4.8%. These are the reported percentages; no additional count or denominator has been inferred from them. The registry record does not supply further detail about event duration, recurrence, severity grading, or relatedness to CPX-351.

General statistical context: safety proportions describe how often events were recorded in the group and depend on the observation period, event definitions, and reporting practices. They do not, without a comparator and appropriate attribution information, estimate excess risk caused by a treatment. The single-group design limits comparative safety interpretation, and the listed figures should be read as descriptive registry entries.

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

The study record describes a phase II, single-group evaluation of CPX-351 in patients younger than 60 years with secondary acute myeloid leukemia. It identifies a primary response outcome at day 45, defined as CR or CRi, and states that 19 patients were evaluable for disease response out of 21 enrolled. It also lists secondary outcomes and safety information. These details define the question and the scope of the record, but do not supply the primary response result.

The record does not report the number of evaluable patients who achieved CR, CRi, or the combined endpoint. It therefore does not establish a response rate or allow its precision to be assessed. The stated endpoint definition is not evidence of a particular outcome. Nor does the number enrolled serve as a substitute for the response result or tell the reader how the two patients outside the evaluable population were handled.

The study design does not include a separate randomized comparator group in the registry record. General statistical context: an outcome observed in a treated group is a description of that group; comparison with an appropriate control is needed to estimate a treatment contrast and support stronger causal interpretation. The registry record does not permit a conclusion about how outcomes would differ under another treatment or no treatment.

The safety entries indicate that 10 of 21 participants were listed with serious adverse events, 20 of 21 with other adverse events, and 13 deaths were listed. The record does not establish from these figures the timing, cause, or treatment relatedness of events or deaths. The serious-event percentages are descriptive and should not be interpreted as proof that CPX-351 caused any listed event.

More generally, the existence of named secondary outcomes does not show that numerical results or analysis details are available. The registry record does not report numerical results for the named secondary outcomes in the information analyzed. The appropriate conclusion is limited: the record specifies a study design, a primary endpoint, an evaluable response population, and selected safety figures, while leaving the primary response result and several analysis details unreported.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of how a clearly named endpoint and a defined assessment time do not, by themselves, provide enough information to estimate an outcome. The registry specifies a combined CR and CRi response measure at day 45, and identifies 19 patients as evaluable. Without the response count, however, the central descriptive estimate cannot be obtained from the registry record. Readers need both the outcome numerator and the analysis denominator to interpret a response frequency.

The difference between enrollment and endpoint evaluability also highlights why analysis populations matter. The record lists 21 enrolled participants but 19 evaluable for disease response. It does not state the reasons for this distinction or describe the handling of participants without an evaluable response. General statistical context: transparent population definitions and missing-data procedures help readers assess how much the analyzed group represents the enrolled group and how robust an estimate may be.

The single-group design further illustrates the distinction between outcome description and comparative inference. Even when numerical outcomes are available, one group alone cannot show what would have happened to comparable participants under another option. That design feature is important when interpreting both response and safety data; it is not resolved by a larger set of secondary outcome names.

The listed adverse-event figures also emphasize the need to distinguish recorded events from causal effects. Participant counts and event percentages describe what was reported in the treatment group, while causal attribution and comparative risk require additional information. The record lists no randomized comparator, and it does not report event timing or treatment relatedness in the information.

These features make the record useful for statistical reading: it illustrates the need to separate design, endpoint definition, analysis population, numerical result, and causal interpretation. The available registry information answers some of those questions, but not all. In particular, it identifies the response framework without reporting the response outcome itself.

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.

Several limitations arise from the information reported for this study. The primary response endpoint is defined at day 45, but its result is not reported in the registry record. No number of patients with CR, CRi, or the combined response is given, and no response proportion or confidence interval is reported. This prevents quantitative interpretation of the primary endpoint.

The record states that 19 patients were evaluable for disease response out of 21 enrolled, but does not explain why the counts differ. It does not describe the disposition of the other participants, missing assessment handling, or whether any sensitivity analysis was conducted. As a result, the relationship between enrollment and the primary analysis population cannot be evaluated further.

The single-group design, with allocation listed as not applicable, has no separate randomized comparator in the record. This limits interpretation to outcomes observed in the treated group and does not provide a like-for-like treatment contrast. No masking is listed. The registry record also does not report a detailed statistical analysis plan, an interim analysis plan, a sample-size justification, or analysis records.

Safety entries provide counts for serious and other adverse events and a death count, along with selected serious-event terms and percentages. The record does not establish event timing, individual overlap between categories, cause of death, or treatment relatedness in the information. Numerical results and analysis details for the named secondary outcomes are also not reported in the registry record.

These limits do not imply that unreported procedures or data were absent from study conduct; they indicate that the registry record does not report them. Conclusions should therefore remain confined to the stated design, endpoint definition, population counts, and listed safety figures.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: CPX-351 for the Treatment of Secondary Acute Myeloid Leukemia in Patients Younger Than 60 Years Old — NCT04269213.
• Registry record last updated 2026-09-08; status last verified 2026-09.
• Results first posted 2026-08-31.
• 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 NCT04269213, a completed phase II study of CPX-351 in patients younger than 60 years with secondary acute myeloid leukemia. The study is listed as single-group, with allocation not applicable and no masking. It reports 21 participants enrolled and identifies 19 patients evaluable for the primary disease response outcome.

The primary endpoint is the number of participants with CR or CRi at day 45, defined by the International Working Group Criteria and intended to be summarized using frequencies and relative frequencies. The response count and rate are not reported in the registry record. Named secondary outcomes include CR plus CRi duration, event-free survival, overall survival, allogeneic hematopoietic cell transplant rate, and adverse events.

For the treatment group, the record lists 10 of 21 participants with serious adverse events, 20 of 21 with other adverse events, and 13 deaths. It also gives percentages for selected serious adverse event terms. The record lists six outcome measures and no analysis records; further statistical analysis details are not reported in the registry record.