A Phase I Study of OCV-501 in Acute Myeloid Leukemia Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Phase I Study of OCV-501 in Acute Myeloid Leukemia Patients (NCT01440920), a non-randomized phase 1 study. The primary outcome is Occurrence of Dose Limiting Toxicities.

2. Clinical Question

The clinical question is therefore a safety and tolerability question, not a comparison of OCV-501 with another treatment. The listed dose levels describe the cohorts but do not, on their own, establish a dose-response pattern. Since there is no randomized comparator and no reported primary-endpoint analysis, the registry record cannot support a causal comparison between doses or a conclusion about the frequency of DLTs. The descriptive safety counts can be read as cohort-level observations, with the limitations of the small cohort sizes and absent analysis details in mind.

3. Trial Design

The registry record identifies this as a Phase I study with non-randomized allocation, no masking, and a single-group model. It lists three cohorts receiving OCV-501 at different dose levels: 0.3 mg, 1 mg, and 3 mg. Each cohort has three participants at risk in the safety information, and the overall enrollment is 9. The record marks the study as completed. Its listed start is 2011-09 and its primary completion is 2013-03.

The study population was patients with acute myeloid leukemia who had achieved complete remission after an induction regimen and completed standard consolidation therapy. The stated purpose was assessment of OCV-501 safety and tolerability in this population. The record does not report further detail about eligibility criteria, the dose assignment process, administration schedule, or how participants entered the different cohorts. These aspects should not be inferred from the dose levels alone.

Because allocation was non-randomized and there was no masking, the cohort descriptions do not constitute a randomized comparison. No control treatment is listed. Cohort-level observations can describe what was recorded among participants at the respective dose levels, but they cannot isolate a causal effect of dose from other possible differences between cohorts. The registry record does not report whether a formal dose-escalation rule, stopping rule, or other decision procedure governed cohort assignment.

The primary endpoint was occurrence of DLTs, with a timeframe of 4 Weeks. A secondary outcome listed in the record was recurrence based on the Response Evaluation Criteria by the International Working Group. The record lists 2 outcome measures, but no outcome analyses are listed. Statistical analysis methods, analysis populations, and handling of missing outcome data are not reported in the registry record. The study’s phase and stated safety purpose provide context, but they do not fill in these unreported design and analysis details.

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

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 Occurrence of Dose Limiting Toxicities, measured over 4 Weeks.

The primary endpoint is the occurrence of dose-limiting toxicities, recorded as a count of participants, over the stated 4 Weeks timeframe. The registry defines a DLT as a qualifying adverse event by Day 29, which is 7 days after the last investigational medicinal product administration, where a causal relationship to the investigational medicinal product could not be ruled out. Adverse-event severity was evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events, ver. 4.0.

The registry definition includes non-blood toxicities at least Grade 3, with specified exceptions for anorexia, nausea, vomiting, diarrhea, and constipation when supportive therapy makes it possible to continue the clinical trial. It also includes blood toxicities at least Grade 4, with febrile neutropenia at least Grade 3 counted as a DLT. Blood toxicity did not include hematology parameters of laboratory tests.

In general, a DLT endpoint is used in early-phase research to describe serious or otherwise protocol-defined toxicity within a specified observation window. The count of participants meeting a predefined toxicity rule is a direct descriptive measure, but interpretation depends on complete reporting of the qualifying events, assessment window, and evaluated population. The registry record does not report the primary endpoint count or an analysis by cohort. Thus, the endpoint definition is available, but its observed result cannot be stated from the registry information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The reported primary endpoint is binary at the participant level: each participant either meets the registry definition of DLT within the stated observation window or does not. The registry describes the measure as a number of participants. In general, binary outcomes are often summarized using the number of participants with an event and the number evaluated. The count is directly interpretable, while an estimated event proportion or model-based comparison requires an analysis method and an appropriate denominator. The primary-endpoint result and its denominator by cohort are not reported in the registry record.

The DLT definition determines which events count toward the endpoint. The record ties qualification to timing, severity, and whether a causal relationship to the investigational medicinal product could be ruled out. It specifies the event window through Day 29, 7 days after the last investigational medicinal product administration, and states a 4 Weeks timeframe. It also sets different severity thresholds for blood and non-blood toxicities and gives exceptions for certain non-blood events when supportive therapy permits continuation. These details are important because a count can change depending on the endpoint definition. The record does not report how many events fell into each category or how attribution decisions were made in practice.

In general, a confidence interval expresses uncertainty around an estimate. For a binary event count, interval methods can reflect the fact that information is limited when few participants are evaluated. An interval is not a guarantee that the true value lies within its limits; it is a statistical summary under stated assumptions and a specified method. No confidence interval, standard error, or other precision measure for the DLT endpoint is reported in the registry record. A precise interpretation of the primary result is consequently not possible from the available outcome information.

For cohort-level descriptive summaries, the event count and denominator should be read together. The serious adverse-event figures report 0 affected participants among 3 at risk in each cohort; the other adverse-event figures report 3 affected participants among 3 at risk in each cohort. In general, counts of participants affected do not describe the number of separate events, event severity, duration, or relationship to treatment unless those details are reported. The registry’s broad safety counts should therefore not be read as a complete clinical characterization of individual events. No serious adverse-event terms are listed.

Comparative analyses require particular care. In a randomized study, random assignment can support a balanced comparison in expectation, subject to study conduct and missing data. This study is marked non-randomized, has no masking, and is described as single-group, with three dose cohorts and no control treatment listed. In general, unadjusted differences between non-randomized groups may reflect differences in who entered each group as well as differences associated with the intervention. The registry record does not report a comparative model, covariate adjustment, or a formal test across dose cohorts.

For time-to-event outcomes, general methods account for when events occur and for participants whose event status is not observed throughout follow-up. The listed secondary outcome concerns recurrence, but no recurrence results, follow-up details, or analysis methods are reported in the registry record. There is therefore no basis for describing a time-to-event estimate or its precision for recurrence.

The registry describes sample-size planning illustrations as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect set as a stated fraction of the observed effect. These assumptions describe planning calculations rather than the trial’s reported design. In general, sample-size planning asks how much information a proposed study might need under chosen assumptions; it does not measure the probability that an observed result is true. The illustrations are not observed power, and their two-arm equal-allocation setup does not match this study’s three non-randomized cohorts. No trial-specific sample-size justification or statistical analysis plan is reported in the registry record.

The record lists 2 outcome measures and 0 analyses. This means the registry information described for this study does not present an outcome analysis to evaluate. General statistical interpretation depends not only on endpoint definitions but also on the analysis population, missing-data approach, handling of multiple outcomes, and prespecified analysis choices. These details are not reported in the registry record. Without them, readers should distinguish recorded descriptive counts from inferential claims that would require a documented 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("Cohort 1", "Cohort 2", "Cohort 3")
n      <- c(3, 3, 3)
events <- c(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  Cohort 1  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2
ARM  Cohort 2  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2
ARM  Cohort 3  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 2 outcome measures: the primary DLT endpoint and recurrence as a secondary outcome. It lists 0 analyses. The record does not report a statistical analysis plan, an approach to multiplicity, or results for the listed recurrence outcome. It is therefore not possible to determine whether any adjustment for testing multiple outcomes was planned or applied.

In general, multiplicity arises when several hypotheses or outcomes are examined. Repeated testing can increase the chance of at least one apparently notable result under a specified statistical framework. Researchers may address this with prespecified testing strategies or adjustment methods, but no such strategy is reported in the registry record. Since no analyses are listed, no multiplicity-adjusted or unadjusted inferential result can be described.

The registry record also does not report missing-data counts, reasons for missingness, or a method for handling missing observations. It does not identify the analysis population for the primary or secondary outcomes. These details affect interpretation because the denominator may differ from total enrollment, and missing outcome information can influence estimates when it is not evenly distributed or otherwise ignorable. The cohort safety counts give 3 participants at risk per cohort, but the record does not establish that these are the denominators for every outcome.

In general, a complete account of analysis populations explains who was included for each endpoint and how participants with incomplete assessments were treated. Without this information, the primary DLT result and recurrence outcome cannot be reconstructed or assessed for robustness. The registry record does not report these analysis details.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The cohort safety information lists serious adverse events, other adverse events, and deaths. For serious adverse events, the affected-participant count is 0 in Cohort 1, 0 in Cohort 2, and 0 in Cohort 3; each cohort has 3 participants at risk. For other adverse events, the affected-participant count is 3 in each cohort, with 3 at risk in each. Deaths are listed as 0 in all three cohorts. No serious adverse-event terms are listed.

These are counts of participants, not a full description of event episodes. In general, a participant count does not reveal how many separate events occurred, how long they lasted, or their severity unless those details are reported. The registry’s broad categories also do not identify whether an adverse event met the study’s distinct DLT definition. The DLT endpoint has its own timing, severity, and attribution criteria, and its result is not reported in the registry record.

The cohorts are small and non-randomized, with no control group listed. These safety counts should therefore be read descriptively, rather than as a comparative estimate of risk or proof that an event cannot occur. The registry record does not report further detail about event terms or a statistical analysis of the safety counts.

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

The registry record establishes the study’s setting and endpoint definition: this was a completed Phase I study of OCV-501 in patients with acute myeloid leukemia who had achieved complete remission after induction and completed standard consolidation therapy. It describes three non-randomized dose cohorts and identifies occurrence of DLTs as the primary endpoint within 4 Weeks. The record’s safety counts also report no serious adverse events or deaths in the listed cohorts, while other adverse events are recorded for all participants at risk in each cohort.

Those observations do not answer the primary question about the number of participants who met the DLT definition. That result is not reported in the registry record. The broad safety categories cannot be substituted for the endpoint because the endpoint uses a particular event definition, severity threshold, time window, and causal-attribution rule. The secondary recurrence outcome also has no reported analysis.

The study’s non-randomized, single-group design does not support a randomized comparison of doses or a comparison against another treatment. The cohort counts describe the participants listed in the registry, not what would necessarily occur in another group or under another treatment. No causal claim about dose can be drawn from these counts alone. The record does not report a statistical comparison, precision estimates for the primary outcome, or analysis methods that would support broader inference.

In general, early-phase safety observations can inform understanding of events recorded during a study, but their interpretation depends on the number and characteristics of participants, follow-up, event definitions, and analysis completeness. Here, the registry provides the endpoint definition and cohort safety counts but not the primary outcome analysis, missing-data information, or detailed analysis populations. The available information therefore supports a limited descriptive account, not a definitive estimate of DLT frequency or a conclusion about treatment effects.

Any planning calculations should likewise be kept separate from study findings. The registry characterizes its planning illustration as based on an observed effect under assumptions that do not match the recorded cohort structure. Such an illustration is not observed power and does not replace a trial-specific sample-size justification, which is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how design labels, endpoint definitions, and outcome reporting shape what can be concluded from an early-phase study. The registry identifies a specific DLT rule with an observation window, severity criteria, and attribution condition. Those details show why the endpoint cannot be inferred from broad adverse-event counts alone.

The design also matters. Three cohorts received different dose levels, but allocation was non-randomized and no control group is listed. This makes the cohort data descriptive rather than a randomized dose comparison. A numerical difference between non-randomized cohorts, even if reported, would not by itself isolate a dose effect. In this record, the primary endpoint analysis is not reported, so even that descriptive DLT comparison is unavailable.

The safety counts illustrate the distinction between what is observed and what is established. No serious adverse events and no deaths are listed in the cohorts, while other adverse events are recorded for each participant at risk. Such counts convey the reported experience of these participants, but they do not provide a precise estimate of underlying event frequency or characterize event details that are not listed.

The record’s planning illustration provides a further statistical lesson: calculations based on assumptions about a two-arm, equally allocated comparison should not be mistaken for the design or inferential strength of a three-cohort, non-randomized study. Planning values are not observed power. The registry record does not report a trial-specific sample-size justification, analysis plan, or outcome analyses. Recognizing these boundaries helps readers distinguish endpoint definitions, recorded safety observations, and evidence that would require a reported statistical analysis.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary limitation is that the registry record does not report the primary DLT result or an analysis, despite providing a detailed endpoint definition. The reader therefore cannot determine the number of participants meeting that definition, its distribution by cohort, or the precision of an estimate. The record also lists recurrence as a secondary outcome without reporting its result or analysis.

The study is non-randomized, unmasked, and described as single-group, with three dose cohorts and no control treatment listed. Consequently, the cohort observations cannot support a randomized comparison or a causal conclusion about dose. The registry record does not report how dose assignment occurred or whether a formal cohort decision procedure was used. It also does not report a statistical analysis plan, a trial-specific sample-size justification, or comparative methods.

Although the safety counts include 3 participants at risk in each cohort, the record does not describe whether those denominators apply to every outcome. Missing-data counts, reasons for missingness, analysis populations, and methods for handling incomplete observations are not reported. The broad adverse-event counts do not provide event terms for serious events, and no serious adverse-event terms are listed. The record does not provide further event-level detail in the information described.

The registry’s planning illustration assumes equal allocation between two arms and a normal approximation, whereas the study description lists three non-randomized cohorts. These planning assumptions cannot be treated as the original design or as observed power. The limited cohort sizes, lack of a control group, and absent outcome analyses all constrain interpretation of the posted information. These limitations are specific to what is recorded for this study and should be kept distinct from the endpoint’s stated definition.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Phase I Study of OCV-501 in Acute Myeloid Leukemia Patients — NCT01440920.
• Registry record last updated 2021-03-08; status last verified 2021-02.
• Results first posted 2021-03-08.
• 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

This completed Phase I study evaluated OCV-501 in patients with acute myeloid leukemia who achieved complete remission after an induction regimen and completed standard consolidation therapy. The registry lists enrollment of 9, non-randomized allocation, no masking, and a single-group model. It describes three cohorts at 0.3 mg, 1 mg, and 3 mg.

The primary endpoint was occurrence of DLTs over 4 Weeks, using a definition based on timing, severity, and whether a causal relationship to the investigational medicinal product could be ruled out. The record lists recurrence as a secondary outcome and 2 outcome measures, but 0 analyses. The primary and secondary outcome results are not reported in the registry record.

Safety counts list 0 participants with serious adverse events and 0 deaths in each cohort; other adverse events are listed for 3 participants among 3 at risk in each cohort. No serious adverse-event terms are listed. The non-randomized design, lack of a control group, and missing outcome analyses limit the conclusions that can be drawn from these records.