Safety Study Of Chemotherapy Combined With Dendritic Cell Vaccine to Treat Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety Study Of Chemotherapy Combined With Dendritic Cell Vaccine to Treat Breast Cancer (NCT02018458), a non-randomized phase 1, phase 2 study. The primary outcome is Safety of DC Vaccine Combined With Chemotherapy.

2. Clinical Question

The trial also listed secondary objectives concerning pathologic complete response, disease-free survival, immune biomarkers in biopsy specimens and blood, and the feasibility of immunizing patients with patient-specific tumor antigens. These objectives describe what investigators intended to assess; they do not establish that results for each objective were reported. Numerical findings for the secondary outcomes are not reported in the registry record.

The central statistical question is therefore descriptive: what safety-event counts were posted for the group with results, and how much can those counts establish about safety? Because the study was non-randomized and has no reported comparator group, its results cannot separate the effects of the vaccine from chemotherapy, the underlying disease, or other influences. They can describe observed events in the reported safety population, but do not provide a controlled estimate of treatment effect.

3. Trial Design

This is a completed phase 1 and phase 2 pilot trial registered as NCT02018458. It used a non-randomized, open-label, parallel design. The registry reports enrollment of 10 and a primary completion date of 2019-09-18. The listed condition is breast cancer, and Baylor Research Institute is the sponsor.

The trial included groups for patients with locally advanced triple-negative breast cancer and ER-positive, HER2-negative breast cancer. The registry reports results only for the locally advanced triple-negative group. It states that the other group did not enroll patients with the specified hormone-receptor criteria. This means the posted results do not provide a second group for comparison, and the listed groups should not be interpreted as randomized treatment arms.

Both groups were assigned a combination of dendritic cell vaccine and preoperative chemotherapy. The locally advanced triple-negative description specifies standard preoperative AC followed by TCb chemotherapy for 24 weeks. The ER-positive, HER2-negative description specifies standard preoperative AC followed by weekly T for 22 weeks. The descriptions state that chemotherapy and dendritic cell vaccinations were given intratumorally and subcutaneously, with four vaccinations before surgery. For the locally advanced triple-negative group, the registry says vaccinations during AC cycles were given on any day between Days 9-12 of Cycles 1 and 3. The detailed descriptions in the registry are truncated, so additional scheduling details are not reported in the registry record.

Non-randomized allocation and the absence of masking are consistent with a pilot focused on safety and feasibility rather than a blinded comparative efficacy estimate. However, the protocol rationale, any formal sample-size justification, and the statistical analysis plan are not reported in the registry record. The record does not report analyses for the secondary outcomes. The design and available results therefore support a limited descriptive reading of safety events, not a causal comparison between the vaccine combination and 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.

Before assignment: Arm "ER+/HER2- BC: DC vaccine + preop chemo" is not included in these results, as no participants were enrolled in this arm with these hormone receptor criteria.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Results are only reported for Arm 1, "LA TNBC: DC vaccine+preop chemo patients". Arm 2, "ER+/HER2- BC: DC vaccine+preop chemo patients" did not enroll any patients with these hormone receptor criteria.

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 Safety of DC Vaccine Combined With Chemotherapy, measured over 4 years.

The primary outcome is titled “Safety of DC Vaccine Combined With Chemotherapy.” It is measured as a count of participants, rather than as a continuous score or a rate per unit of person-time. The outcome description says toxicities were graded according to NCI Common Terminology Criteria for Adverse Events Version 4.03. The stated safety population includes eligible and ineligible patients who received at least one inoculation of dendritic cell vaccine therapy; it was also intended for summaries of safety parameters such as drug exposure and adverse events, including serious adverse events.

A participant count is useful in a pilot safety study because it gives a direct account of how many people in the reported group experienced an event. It is readily interpretable as a descriptive result, but it does not by itself show when events occurred, how long participants were observed, whether an event was related to vaccination or chemotherapy, or how the event frequency compares with another treatment. Those details require additional definitions or a comparator.

The registry lists a timeframe of 4 years for the primary outcome. The posted safety figures include participants at risk, participants affected by serious and other adverse events, and deaths. The registry record does not provide confidence intervals, event-level timing, or an attribution of those deaths to treatment. The counts should therefore be read as descriptions of the reported safety population, not as proof of a cause or as a precise estimate of comparative risk.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation depends on what the design and outcome definitions can support. This trial is non-randomized, has no masking, and has parallel groups defined by breast cancer characteristics. The registry reports safety findings for the locally advanced triple-negative group only; it says the other group did not enroll patients with the specified hormone-receptor criteria. The available results are therefore descriptive rather than a randomized comparison.

What does a participant count represent?

A participant count records how many people in the specified analysis population were identified as having an outcome. It is different from an event count: one participant could have more than one event, and an event listing can contain multiple terms. The posted safety outcome is described as a count of participants. The serious and other adverse-event counts should be understood in that participant-based context, rather than assumed to be totals of every event occurrence.

The safety population is described as including eligible and ineligible patients who received at least one vaccine inoculation. The posted group lists 10 participants at risk for the serious adverse event measure and 10 at risk for other adverse events. The registry does not provide further participant-level details or clarify overlap between event categories in the information available for this analysis. Counts for separate categories should not be added to infer a number of unique people.

Why does the design matter?

Random allocation, when used, can balance measured and unmeasured characteristics across treatment groups on average. That supports a more credible estimate of a treatment contrast. Here, allocation was non-randomized, and the listed groups represent different receptor-defined populations with different chemotherapy descriptions. They are not exchangeable control groups. A comparison between them would mix treatment differences with differences in the populations and treatment regimens.

Masking was absent. In general, lack of masking can affect how symptoms are reported, assessed, or recorded, although the registry does not establish that this occurred in this trial. For safety outcomes, objective definitions and consistent grading are important. The registry says toxicities were graded using CTCAE Version 4.03, but does not report detailed adjudication procedures or event attribution.

What can confidence intervals add?

In general, a confidence interval expresses the statistical precision of an estimate under a stated model and sampling framework. A wider interval indicates less precision; a narrower interval indicates greater precision. For a participant count or an event proportion, an interval can communicate uncertainty that a point estimate alone does not show. However, a confidence interval does not correct confounding, create a control group, establish causation, or resolve incomplete outcome reporting.

Confidence intervals for the primary safety outcome are not reported in the registry record. The record also does not report a comparative effect estimate or a statistical test for the safety outcome. Thus, the posted counts can be described, but formal precision and evidence against a comparator cannot be assessed from the record.

Why can event timing and exposure matter?

General safety analysis distinguishes the number of people with an event from the number of events and from the rate of events over time. Participants may have different observation periods or exposure to treatment. A rate analysis can account for time at risk when appropriate, while a time-to-event analysis considers when the event occurs and whether follow-up ends before an event. The registry gives a 4 years timeframe for the primary outcome, but does not report person-time, event timing, censoring details, or a time-to-event safety analysis.

Over-dispersion is a general concern when event counts vary more than a simple statistical model expects. It can make model-based uncertainty too small if the extra variation is ignored. This issue cannot be evaluated from participant-level data or model details that are not reported; no such analysis is reported in the registry record. For the posted participant counts, the more immediate limitations are the lack of a comparator, the small reported safety population, and missing detail about events.

How should planning illustrations be read?

In general, a sample-size calculation describes the number of participants a future study might need under stated assumptions. It is a planning illustration, not an observed feature of the completed trial and not a measure of its power after the results are known. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. Time-to-event illustrations use a total number of events; other illustrations use participants per arm.

Those assumptions do not show that this trial used that planning method. The registry record does not report its own sample-size justification, and calculated planning requirements should not be interpreted as observed power. Any planning result is conditional on the effect and statistical assumptions used; it does not establish that a future study will achieve the assumed effect or that the present study can test it precisely.

What analyses are reported?

The record lists no analyses for the reported outcomes. It also does not report a statistical analysis plan, model specifications, adjustment variables, handling of missing observations, or multiplicity procedures. Without those details, it is not possible to determine whether any unposted analyses were prespecified or to reconstruct an inferential analysis from the participant counts alone. The interpretation should stay close to the descriptive information 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("LA TNBC: DC Vaccine+Preop Chemo")
n      <- c(10)
events <- c(10)
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  LA TNBC: DC Vaccine+Preop Chemo  10  10  100.0  69.2  100.0  72.2  100.0  71.5  99.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary safety objective and secondary objectives that include pathologic complete response, disease-free survival, immune biomarkers, and feasibility. The secondary outcome list identifies pathologic complete response rate and disease-free survival. Numerical results for those secondary outcomes are not reported in the registry record summarized for this trial. The number of analyses is listed as 0.

Multiplicity arises when researchers make several statistical comparisons or evaluate several outcomes. In general, the more analyses conducted, the greater the chance that at least one result may appear notable by chance if no adjustment or interpretation plan is used. The registry record does not report a multiplicity strategy, so it is not possible to assess how multiple outcomes or analyses were handled. This is particularly relevant when interpreting a broad set of safety and secondary objectives, but no unreported testing should be inferred.

The registry does not describe how missing outcome data were handled, whether participants withdrew or were lost to follow-up, or whether any outcomes were unavailable. The safety outcome description defines the intended population as eligible and ineligible patients who received at least one inoculation. Beyond that definition, reasons for exclusion from a particular analysis and the completeness of follow-up are not reported in the registry record.

Analysis populations can differ according to eligibility, treatment received, or outcome availability. The stated safety population is based on receiving at least one inoculation, but the registry does not provide a separate accounting of all such analysis decisions. Without participant-level flow and missingness information, the extent to which the posted findings represent the full enrolled group cannot be established. No statistical method for imputing or otherwise handling missing observations is reported.

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: pulmonary embolism (10.0%), right atrial thrombosis (10.0%), cellulitis of right breast (10.0%), dyspnea (10.0%).

The registry lists 10 participants at risk for both serious and other adverse-event measures in the locally advanced triple-negative group. It reports 3 participants affected by serious adverse events and 10 affected by other adverse events. These are participant counts, not necessarily counts of individual event episodes. A participant may appear in more than one event category, and the registry record does not state the overlap.

The serious-event terms listed are Pulmonary Embolism, Right atrial thrombosis, cellulitis of right breast, and dyspnea, each shown as 10.0%. These terms and percentages describe entries in the posted results; the record does not clarify whether each term represents an affected participant, how multiple terms within a person were handled, or whether any event was judged related to the study treatment. The percentages should not be treated as evidence of causation.

The record also reports 4 deaths. It does not specify in the posted information whether those deaths were related to treatment, when they occurred, or how they were classified relative to the adverse-event summaries. The 4 years primary-outcome timeframe does not by itself establish the follow-up duration for each participant or the timing of each event. No comparison group or confidence interval is reported. These figures are therefore best read as descriptive safety reporting, not as a comparative risk estimate.

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

The record establishes that a completed pilot trial evaluated the combination of preoperative chemotherapy and a dendritic cell vaccine, with a primary objective focused on safety and feasibility. It reports participant-based safety counts for the locally advanced triple-negative group. It also identifies several serious adverse-event terms and reports a death count. These observations are relevant to describing what was recorded in that group.

The record does not establish that the vaccine caused any listed adverse event or death. The treatment combined vaccination and chemotherapy, and the registry does not report attribution details that would distinguish the contribution of either component from the underlying disease or other causes. Without a control group, the event counts also cannot show whether the combination led to more or fewer events than another treatment approach.

The findings do not establish a treatment effect on pathologic complete response or disease-free survival. Those outcomes are listed as secondary objectives, but numerical results are not reported in the registry record for the information summarized. The record likewise does not provide numerical immune-biomarker findings. It is not possible to infer an efficacy benefit, lack of benefit, or a relationship between immune response and clinical outcomes from the posted safety counts.

Precision is also limited by the amount of information reported. The available safety group is small, and no confidence intervals, formal comparative estimates, or analysis details are reported. The counts can signal which events were recorded, but cannot by themselves provide a precise estimate of how often such events would occur in a broader population. The record’s 4 years timeframe does not supply individual follow-up times or event timing.

In practical statistical terms, this is a descriptive pilot record rather than a definitive comparative assessment. Its value lies in documenting a combination regimen and the safety events reported for the group with results. Further conclusions would require information not reported in the registry record, including event attribution, complete follow-up, secondary outcome findings, and comparative data.

14. Why This Trial Matters Statistically

This trial illustrates why a safety question should be separated from an efficacy question. The primary objective concerns safety and feasibility, whereas pathologic complete response and disease-free survival are listed as secondary objectives. Each requires an outcome definition and a suitable analysis. A safety count can describe events in the observed group, but it does not answer whether an intervention improves a clinical outcome.

It also highlights the limits of a non-randomized design. The registry describes distinct disease groups, different chemotherapy regimens, and no randomized control arm. The second group did not enroll patients meeting the specified hormone-receptor criteria. Consequently, the posted results cannot support a between-group treatment comparison. This matters because statistical contrasts are only meaningful when the groups and treatment assignments support the comparison being asked.

The record further shows the difference between reporting event counts and reporting uncertainty. Counts are direct and accessible, but without confidence intervals or a comparative estimate, their precision and context remain limited. Event terms and a participant count do not replace information about timing, attribution, exposure, or follow-up. Those details shape what a safety result can reasonably mean.

Finally, the listed secondary objectives and absence of reported analyses underscore the importance of complete outcome reporting. A registry record can state what investigators intended to study without providing numerical findings for every objective. Readers need to distinguish planned assessments from reported results. The main statistical lesson is to match conclusions to the design and data actually available: describe the safety observations, avoid causal or efficacy claims, and recognize that unanswered questions require additional reported 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 key limitation is that safety results are reported for only the locally advanced triple-negative group. The registry says the ER-positive, HER2-negative group did not enroll patients with those hormone-receptor criteria. There is therefore no reported comparison with that group, and the different disease categories and chemotherapy descriptions would not make them a like-for-like control even if both had results.

The trial is non-randomized and unmasked. The record does not report a control group receiving chemotherapy without vaccination, or another comparator. The effects of the vaccine, chemotherapy, disease, and other influences cannot be separated using the posted counts. The registry does not report event attribution, event timing, participant-level data, or individual follow-up duration.

The safety summaries are participant counts and do not fully explain how event terms relate to participants or overlap across categories. Although the primary outcome description states that toxicities were graded using CTCAE Version 4.03, detailed assessment procedures and analysis decisions are not reported. The record lists 4 deaths but does not provide the attribution or timing needed to interpret that count in relation to treatment.

Numerical results for pathologic complete response, disease-free survival, and immune biomarkers are not reported in the registry record summarized for this trial. The record also does not report confidence intervals, statistical tests, a statistical analysis plan, multiplicity procedures, missing-data handling, or a sample-size justification. The detailed arm descriptions are truncated. These gaps limit evaluation of precision, completeness, and reproducibility, and they prevent conclusions beyond the descriptive safety information posted.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety Study Of Chemotherapy Combined With Dendritic Cell Vaccine to Treat Breast Cancer — NCT02018458.
• Registry record last updated 2021-10-11; status last verified 2021-10.
• Results first posted 2020-03-13.
• 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

NCT02018458 is a completed phase 1 and phase 2, non-randomized, open-label, parallel pilot trial sponsored by Baylor Research Institute. It evaluated preoperative chemotherapy combined with a dendritic cell vaccine in patients with breast cancer. The registry reports enrollment of 10 and primary completion on 2019-09-18.

The primary objective was safety and feasibility. Safety results are reported for the locally advanced triple-negative group only; the ER-positive, HER2-negative group did not enroll patients with the specified hormone-receptor criteria. The posted group has 3 participants affected by serious adverse events, 10 affected by other adverse events, and 4 deaths. Four serious-event terms are each listed at 10.0%.

Pathologic complete response and disease-free survival are listed as secondary outcomes, but numerical findings are not reported in the registry record. The available information supports a descriptive reading of safety counts only, not a comparative or causal treatment conclusion.