Sequencing of Sipuleucel-T and ADT in Men With Non-metastatic Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sequencing of Sipuleucel-T and ADT in Men With Non-metastatic Prostate Cancer (NCT01431391), a randomized phase 2 study. The primary outcome is Immune Response at Month 24 as Evaluated by IFN-γ ELISPOT Specific for PA2024.

2. Clinical Question

The trial addressed a sequencing question: whether the immune response measured after treatment differed between participants who received sipuleucel-T before ADT and those who received ADT before sipuleucel-T. Its focus was the biological response to the treatment regimens. The registry also describes evaluation of safety, immune responses over time, characteristics of sipuleucel-T, and changes in prostate specific antigen over time.

The posted primary comparison is between the mean ELISPOT counts for the two sequences at month 24. It estimates the difference in that measure between the treatment groups. It does not by itself establish whether any difference would matter to patients, nor does the registry record report a clinical-outcome threshold for interpreting the assay. The study is Phase 2 and open-label, so the result should be read as evidence from this particular randomized comparison rather than as a definitive answer to every question about treatment sequencing.

3. Trial Design

This was a randomized, open-label, parallel-group Phase 2 trial. Participants were assigned to one of two treatment sequences: sipuleucel-T followed by ADT, or ADT followed by sipuleucel-T. The registry record lists Dendreon as the sponsor, enrollment of 68, a start date of 2011-09, primary completion in 2014-12, and a completed status. Masking was listed as none.

In the sipuleucel-T-first arm, participants received one infusion every two weeks for a total of three infusions. The registry description says ADT with a 45 mg leuprolide acetate depot injection began two weeks after the third infusion. It also mentions an additional leuprolide acetate injection at 6, but the posted arm description is cut off at that point. In the ADT-first arm, ADT with a 45 mg leuprolide acetate depot injection began 12 weeks before the first sipuleucel-T infusion. The description states that an additional injection was given 6 months after the first injection, for a total of 2 injections and 12 months of ADT. The remaining arm description is truncated, so any further schedule detail is not reported in the registry record.

The primary endpoint population was defined as all randomized participants who received three sipuleucel-T infusions. This is a specified analysis population, and it is not the same as an unrestricted all-randomized population. The registry record reports 19.0 participants in the sipuleucel-T-first primary endpoint group and 26.0 in the ADT-first primary endpoint group. The record does not explain the difference between those group sizes and the overall enrollment, or report a detailed participant-flow account. The number of participants included in each analysis should therefore be interpreted in the context of the endpoint-specific population definitions.

Randomization helps create a basis for comparing the sequences, while the parallel design means the posted groups represent separate treatment paths. Because the trial was open-label, participants and study personnel were not masked to treatment sequence. Details of allocation concealment, randomization procedures, and the original sample-size justification are not reported in the registry record.

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: The immune response population was defined as all randomized subjects who received 3 infusions of sipuleucel-T.

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 Immune Response at Month 24 as Evaluated by IFN-γ ELISPOT Specific for PA2024, measured over PA2024 ELISPOT counts at Month 24.

The primary endpoint was immune response at month 24, measured using IFN-γ ELISPOT specific for PA2024. The unit is ELISPOT counts per 300,000 PBMC, and the posted summary statistic is the mean. The endpoint description says the comparison was intended to determine whether the order of sipuleucel-T and ADT affected immune response after the treatment regimens.

ELISPOT is an assay-based measure of immune-cell activity in response to a specified target. In general, a count-based assay provides a quantitative way to compare the measured response between groups. A group mean describes the average observed assay value; it does not describe every participant's response or the range of individual values. The registry reports standard errors alongside the group means. A standard error describes uncertainty around an estimated group mean, rather than the spread of individual measurements.

This is a biological endpoint rather than a direct patient-centered clinical outcome. An immune-response measurement can help address a mechanistic question, but its interpretation does not automatically establish an effect on cancer-related outcomes, symptoms, or survival. Those outcomes, and any relationship between this assay and them, are not reported as results in the registry record. The endpoint is also defined for participants who received three sipuleucel-T infusions, so its interpretation applies to that stated population rather than necessarily to every randomized participant.

7. Results Posted in the Registry

• Arm 2: ADT Followed by Sipuleucel-T: mean 61.10 versus 81.00 on control; difference -19.90 (95% CI -91.80 to 52.00), standardized effect d = -0.16; z-test p = 0.587.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Percentage of Participants With Immune Response As Evaluated by IFN-γ ELISPOT Specific for PA2024

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Arm 2: ADT Followed by Sipuleucel-T: 85.3% (29/34) versus 87.9% (29/33) on control; risk difference -2.6 percentage points (95% CI -18.9 to 13.7), risk ratio 0.97 (0.80–1.17); unadjusted two-proportion z-test p = 0.756.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Arm 2: ADT Followed by Sipuleucel-T and the control. The interval gives the range of effects that remain compatible with the data.

The secondary immune-response endpoint presents a binary summary at month 24, whereas the primary endpoint compares mean ELISPOT counts. The secondary results show a broadly similar proportion classified as having an immune response in the two treatment-sequence groups. This pattern does not materially settle the uncertainty in the primary mean comparison: the endpoints use different summaries of the assay response, and neither result alone establishes a patient-centered clinical effect.

In general, a binary endpoint depends on a rule that divides participants into response categories. That can make a result straightforward to communicate, but it may conceal differences in the magnitude of responses within each category. A continuous endpoint retains more information about measured values but can be sensitive to the distribution of those values. The registry record does not describe the response threshold in sufficient detail to assess how alternative classifications might affect the secondary result.

The secondary comparison is unadjusted. When several outcomes or analyses are examined, the chance of obtaining an apparently notable result by chance can rise unless the analysis plan accounts for multiplicity. The registry record does not report an adjustment strategy, confirmatory hierarchy, or prespecified distinction between confirmatory and exploratory results. For that reason, the secondary result carries less inferential weight than a result supported by a documented analysis plan and multiplicity control. Its role is descriptive and supportive rather than decisive.

The registry lists a secondary endpoint for the percentage of participants with an immune response, but it does not provide additional reported analyses. It is not possible to determine from the posted record whether other secondary outcomes were analyzed, how they were selected for reporting, or whether a broader family of comparisons was considered. The overall pattern should therefore be read as a limited set of posted immune-response summaries, not as a complete account of all analyses conducted.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Percentage of Participants With Immune Response As Evaluated by IFN-γ ELISPOT Specific for PA2024

9. Statistical Interpretation

10. Statistical Methods Explained

The primary endpoint is continuous: it is a quantitative ELISPOT count summarized by a mean. A mean is a measure of the central level of the observed values. Comparing group means answers whether the average measured response differs between the randomized treatment sequences. It does not imply that all participants had values near the mean, and it does not show the shape of the underlying measurements. Participant-level distributions are not reported in the registry record.

The registry reports standard errors for each mean. In general, a standard error describes the uncertainty of an estimated statistic across repeated samples under a statistical model. It is not the same as the standard deviation, which describes variation among individual observations. The primary summaries list standard errors of 28.0 and 23.7. A larger standard error corresponds to less precise estimation of the group mean, all else being equal. The registry does not report the standard deviations for the primary endpoint directly.

The comparison is expressed as a mean difference, with the ADT-first arm compared against the sipuleucel-T-first arm. The estimate is -19.9. In general, a negative mean difference under this ordering means the estimated average in the comparison group is lower than the reference group's average. Here, that direction agrees with the posted group means. The confidence interval from -91.8 to 52.0 represents a range of values reasonably compatible with the data under the interval's method and assumptions. Since it includes zero, it does not rule out no mean difference. Since it also spans values on either side of zero, it leaves substantial uncertainty about direction and size.

The registry gives an unadjusted p-value of 0.587 for the primary contrast. In general, a p-value measures how unusual data at least as inconsistent with a null model would be if that model were true, subject to the analysis assumptions. It is not the probability that the null model is true. An unadjusted p-value does not account for the possibility of multiple outcome or subgroup tests. The statistical plan and any adjustment strategy are not reported in the registry record, so the p-value is best read as the posted result for this comparison rather than as a fully documented confirmatory analysis.

The standardized effect reported for the mean comparison is -0.164. In general, standardization expresses a difference relative to a measure of variability, which can help describe scale when outcomes use different units. It does not itself establish clinical importance. The registry record does not give a clinical threshold for interpreting this standardized value, nor does it report the rationale used to select a target effect in the original trial design.

For the secondary endpoint, participants are summarized as having or not having an immune response. The group percentages are 88.0 and 85.0. A risk difference compares the proportions classified as having the outcome; the posted contrast is in the direction of a slightly lower response proportion for the ADT-first group. The registry also gives an unadjusted p-value of 0.756. In general, a binary summary can be easier to interpret than a continuous assay count, but it discards information about the degree of response among participants and depends on the response classification rule. The registry record does not provide further detail about that rule in the posted result.

Over-dispersion is a general concern when count outcomes vary more than a simple count model expects. If present, it can make standard errors from an overly restrictive model too small and confidence intervals too narrow. The primary result is reported as a mean with standard error, but the registry record does not describe a count-model analysis or report a diagnostic assessment of over-dispersion. It is therefore not appropriate to claim that a particular count model was used or that this issue was evaluated. The posted summaries alone do not reveal the underlying distribution or whether observations were especially variable.

Randomization supports a comparison of assigned treatment sequences, but the primary analysis population is restricted to randomized participants who received three infusions of sipuleucel-T. In general, restricting an analysis to participants meeting a post-randomization condition can affect comparability if that condition is related to treatment experience or participant characteristics. The registry does not report the reasons participants may have been excluded from this population, nor a sensitivity analysis using a broader population. The posted estimate should therefore be understood as applying to the population defined for the primary endpoint.

The registry reports no posted analyses count and no additional reported analyses. This does not establish that no analyses were performed; it means that such analyses are not reported in the registry record. Details such as covariate adjustment, handling of missing assay values, model diagnostics, and protocol deviations are also not reported. General statistical interpretation can explain what the displayed summaries mean, but it cannot fill in those absent analytic details.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data locate the treatment-sequence contrast. For the primary mean difference, the estimate was -19.9 and the confidence interval extended from -91.8 to 52.0. The interval includes zero, so the posted data do not exclude no difference. It also includes estimates in either direction, leaving uncertainty not just about the size but about the direction of the contrast.

In general, a confidence interval is a range produced by a procedure designed to capture the underlying parameter at a stated rate over repeated use of that procedure, when its assumptions hold. It is not a guarantee that the true value lies in the particular interval, nor is it a range containing a stated fraction of individual participant measurements. The registry record does not identify the confidence level or provide the detailed method used to construct this interval, so those features should not be inferred.

The reported standard errors, 28.0 and 23.7, indicate uncertainty in the group means. Along with the endpoint-specific group sizes of 19.0 and 26.0, these summaries give context for the width of the interval. They do not replace the interval or show the individual data distribution. The record does not post a standard deviation for the endpoint or a participant-level plot that would allow the distribution to be assessed directly.

The interval is compatible with a range of possible differences, including substantial values in either direction. The registry does not define a clinically meaningful margin, so the interval cannot be used to conclude that the sequences are equivalent or that any possible difference would matter clinically. The result is best described as an uncertain estimate of a month 24 immune assay contrast in the stated analysis population.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations, not the enrollment or group sizes observed in this trial. The figures are participants per arm for 80% power and participants per arm for 90% power; they are not total event counts. The exception described for time-to-event outcomes does not apply to these immune-response outcomes, which are not presented as time-to-event endpoints.

The planning calculation assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It uses the observed effect as a reference and considers planning for 100%, 75%, or 50% of that observed effect. The trial's own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column describes the planned number of participants per arm under the stated assumptions for a design with an 80% chance of detecting the chosen effect if that effect is real and the assumptions hold. The 90% column describes the corresponding planning target for a higher chance of detection. These are design calculations, not statements about the probability that the trial result is correct. The listed planning counts become larger when the target effect is smaller, because a smaller difference is harder to distinguish from random variation.

The curve expresses the same planning relationship visually: changing the effect assumed for a future study changes the number of participants per arm needed to reach the selected power target. These figures are based on the observed effect, not on a separate effect established as clinically important. This is not observed power. The illustrations do not retrospectively show the probability that the completed trial detected an effect, and they should not be read as evidence for or against the treatment sequences.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -19.900; pooled standard deviation σ = 121.352.
2. n = 2 × (1.96 + 0.842)² × 121.352² / -19.900² = 583.7, rounded up to 584 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -19.9                      # observed difference in means
sigma <- 121.351545826242                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1431391)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 584 (80% power), 782 (90% power)
 75% of observed effect: n per arm = 1,038 (80% power), 1,390 (90% power)
 50% of observed effect: n per arm = 2,335 (80% power), 3,126 (90% power)
power.t.test: 584.7 
Simulated power at n = 584 per arm: 0.801 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when statistical conclusions are drawn across multiple outcomes, time points, groups, or analyses. In general, testing many hypotheses can increase the chance of at least one apparently unusual result even if none of the underlying effects is real. A prespecified testing hierarchy or adjustment method can help control that risk. The registry record does not report whether the trial used such a strategy, whether the primary endpoint was the sole confirmatory test, or how the secondary endpoint was positioned relative to it.

The record lists the primary month 24 immune-response measure and a secondary percentage-with-response measure. It reports unadjusted p-values for the posted comparisons. No multiplicity adjustment is reported, so the p-values should not be treated as controlling error across a family of outcomes. The registry also lists no reported analyses beyond the posted results. This absence does not show that no additional analyses occurred; additional analysis details are not reported in the registry record.

The primary analysis population is defined as all randomized participants who received three sipuleucel-T infusions. The registry does not explain how participants who did not meet that condition were handled, give a detailed account of missing endpoint measurements, or describe imputation or other missing-data methods. It also does not report whether the primary comparison was repeated in a broader randomized population as a sensitivity analysis. These omissions matter because an analysis restricted after randomization may not preserve all the advantages of randomized assignment if inclusion is related to treatment or participant characteristics.

The registry record does not describe the approach to protocol deviations, treatment discontinuation, or incomplete follow-up for the endpoint. It also does not identify any interim analyses or provide the original statistical analysis plan. These elements are not reported in the registry record; they should not be assumed to have been absent. Without them, the posted summaries can be interpreted as descriptive results for the stated endpoint populations, but the full safeguards around selection, missingness, and repeated testing cannot be assessed.

15. 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: coronary artery disease (2.9%), angina pectoris (2.9%), coronary artery occlusion (2.9%), vertigo (2.9%), chest pain (2.9%).

The serious adverse event summary reports 1 affected participant among 34 at risk in the sipuleucel-T-first group and 5 among 34 at risk in the ADT-first group. These figures describe participants with at least one serious adverse event as reported in the registry. They do not describe the total number of serious events, and they do not establish that the treatment sequence caused the events.

The record also reports other adverse events in 33 of 34 participants in the sipuleucel-T-first group and 34 of 34 in the ADT-first group. These are separate categories in the registry summary; they should not be added to the serious-event counts or interpreted as mutually exclusive participant groups. The listed serious adverse event terms each have a reported frequency of 2.9%: coronary artery disease, angina pectoris, coronary artery occlusion, vertigo, chest pain, and device-related sepsis. The registry does not provide enough detail in these summaries to infer whether terms occurred in the same participant or to compare event severity beyond the serious-event classification.

Deaths are not reported in the registry record. These summaries are descriptive and do not replace a fuller assessment of safety, timing, exposure, or causality.

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

The result describes a randomized comparison of two treatment sequences using a month 24 immune-response assay. The posted primary estimate is the mean difference in PA2024-specific IFN-γ ELISPOT counts, with a confidence interval that includes zero and extends to values in either direction. The available summary therefore leaves substantial uncertainty about the size and direction of the difference in this endpoint.

That uncertainty is not evidence that the sequences are equivalent. Equivalence requires a prespecified margin and an analysis designed to test whether the plausible difference is contained within that margin. No such margin or equivalence analysis is reported in the registry record. Similarly, the result does not establish superiority of either sequence. The p-value is unadjusted, and the registry does not report the full analysis plan or multiplicity strategy.

The measured outcome is an immune assay, not a direct measure of cancer control, survival, symptoms, or quality of life. The posted result cannot establish whether a difference in assay response translates into a difference in those outcomes. The registry record does not report results for such outcomes in the information summarized for this comparison, nor does it specify a threshold at which a change in the assay would be clinically meaningful.

The primary endpoint applies to randomized participants who received three sipuleucel-T infusions. Interpretation should remain tied to that defined population. The record does not report a detailed missing-data account, an analysis of all randomized participants for this endpoint, or sensitivity analyses that could show how robust the result is to alternative population definitions.

Accordingly, the posted findings are best understood as an uncertain estimate of an assay-based immune response under the two assigned sequences in this Phase 2 trial. They neither prove that sequencing has no effect nor demonstrate that one sequence produces a clinically important advantage. Broader conclusions would require evidence beyond the registry summaries and a clear connection between the measured immune response and outcomes relevant to patients.

17. Why This Trial Matters Statistically

This trial is statistically notable because it asks a focused question about treatment order rather than simply comparing a treatment with no treatment. The randomized parallel design provides a framework for comparing the two sequences, and the primary endpoint directly targets the immune response the study set out to examine. That makes the contrast conceptually clear: the estimated difference is between the mean assay responses at month 24 for the two assigned sequences.

The result also illustrates why an estimate should be read together with its uncertainty. The point estimate alone has a direction, but the confidence interval includes zero and spans values favoring either sequence. The interval communicates that the posted data do not pin down the contrast precisely. The p-value is another summary of uncertainty under a null model, but it cannot replace the effect estimate or its interval and does not measure clinical importance.

The distinction between a continuous immune measure and a binary response classification is also important. The primary and secondary summaries address related questions in different ways. Their interpretation depends on how the assay is measured and, for the binary endpoint, how response is defined. A complete statistical account would clarify the analysis population, missing-data handling, multiplicity strategy, and relationship between immune response and clinical outcomes; these details are not reported in the registry record.

Finally, the sample-size illustrations show how planning depends on the effect targeted and the desired power. They are not a retrospective measure of the trial's success or a substitute for an original design rationale. The record does not report that rationale, so the planning figures should remain illustrations rather than evidence about the adequacy of the completed trial.

18. 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 registry record leaves important design and analysis details unreported. The original sample-size justification, randomization procedures, allocation concealment, and full statistical analysis plan are not reported in the registry record. The registry does not specify whether any interim analyses were planned or conducted. These omissions limit assessment of the trial's design safeguards and of whether the posted analyses followed a prespecified plan.

The primary endpoint population was restricted to randomized participants who received three sipuleucel-T infusions. A detailed participant-flow account and reasons for not contributing to that endpoint are not reported. The record also does not describe missing assay values, treatment discontinuations, protocol deviations, or sensitivity analyses. As a result, the extent to which the primary result depends on the defined analysis population cannot be judged from the posted summaries alone.

The trial was open-label, with masking listed as none. The primary endpoint is an assay-based measure, but the registry does not describe laboratory masking, assay quality procedures, or whether the people assessing outcomes were blinded. It would be inappropriate to assume either that such safeguards were used or that they were not used. The endpoint's relationship to clinical outcomes and a clinically meaningful threshold for the assay are also not reported.

The arm descriptions are truncated in the registry record, which limits assessment of the complete treatment schedules. The record also does not report a multiplicity strategy despite posting a secondary endpoint, and it does not provide additional reported analyses. Safety summaries are limited: deaths are not reported in the registry record, and the posted adverse-event counts do not provide timing, exposure-adjusted rates, or a full account of event-level overlap. These limitations counsel against extending the posted summaries beyond their stated populations and outcomes.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Sequencing of Sipuleucel-T and ADT in Men With Non-metastatic Prostate Cancer — NCT01431391.
• Registry record last updated 2017-05-30; status last verified 2017-04.
• Results first posted 2017-05-30.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

NCT01431391 is a completed, randomized, open-label, parallel-group Phase 2 trial sponsored by Dendreon. It enrolled 68 men with non-metastatic prostate cancer and a rising serum prostate specific antigen after primary therapy, comparing sipuleucel-T followed by ADT with ADT followed by sipuleucel-T.

The primary endpoint was the mean PA2024-specific IFN-γ ELISPOT response at month 24 among randomized participants who received three sipuleucel-T infusions. The estimated mean difference for ADT followed by sipuleucel-T relative to the reverse sequence was -19.9, with a confidence interval from -91.8 to 52.0 and an unadjusted p-value of 0.587. The interval reflects substantial uncertainty about the direction and size of the contrast.

The registry also reports a secondary percentage-with-immune-response endpoint and descriptive adverse-event summaries. The original design assumptions, multiplicity strategy, missing-data methods, and additional analysis details are not reported in the registry record.