Treatment With Radiolabeled Monoclonal Antibody HuJ591-GS (177Lu-J591) in Patients With Metastatic Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Treatment With Radiolabeled Monoclonal Antibody HuJ591-GS (177Lu-J591) in Patients With Metastatic Prostate Cancer (NCT00195039), a na phase 2 study. The primary outcome is Define the PSA Response Rate..

2. Clinical Question

The registry record frames the study as an evaluation of 177Lu-J591 in metastatic, androgen-independent prostate cancer. This framing identifies the population, intervention, and intended biomarker outcome; it does not by itself establish how participants’ PSA values changed or whether a prespecified response threshold was reached.

Because there was no concurrent comparator group, the central question is descriptive: what PSA response and other outcomes were recorded after treatment in this study group? A single-group result cannot directly estimate how outcomes would have differed under another treatment or under no study treatment. Differences in patient characteristics, disease course, and observation over time cannot be separated from the treatment experience using this design alone.

The record also lists secondary aims concerning response duration, toxicity, human anti-J591 antibody response, hematological toxicity relative to bone marrow involvement, survival, and tumor targeting. Numerical results for those aims are not reported in the registry record. The clinical question can therefore be described from the stated objectives, but the posted record does not support a detailed account of efficacy or the full range of secondary outcomes.

3. Trial Design

This was a phase 2 study with a single-group model and no masking. The registry lists enrollment of 47 and identifies Weill Medical College of Cornell University as sponsor. The study is marked completed. Its recorded start is 2004-08 and its primary completion is 2012-02.

All patients were assigned to receive 177Lu-J591; the arm description specifies a single dose at 65 or 70 mCi/m2. The antibody preparation is described as J591 chelated at a specific activity of 12-15 mCi of 177Lu per mg of antibody, with enough non-radiolabeled, non-DOTA-conjugated J591 to reach a total antibody dose of 20 mg. The treatment description in the registry record is truncated after the words “Each dose will be a”; further administration details are not reported in the registry record.

There was no random allocation to multiple treatment groups and no masking. The record does not describe a parallel control group. These design features matter when interpreting the endpoint: observations after treatment can describe outcomes in the treated group, but they cannot provide a randomized estimate of a treatment-versus-control contrast.

The primary endpoint was titled “Define the PSA Response Rate.” PSA was to be assessed at baseline, Day 1, 29, 43, 57, 85, week 18, week 24 and every 12 weeks. The registry record describes response as change from baseline at any specified time point. It does not state the response threshold, analysis population, handling of missing PSA measurements, or a statistical comparison.

Other objectives listed in the registry concern duration of biochemical PSA and/or measurable disease response, toxicity, HAHA response, hematological toxicity in relation to bone marrow involvement, survival, and targeting to known tumor sites. The registry record does not provide numerical outcome summaries for these secondary objectives. The design should therefore be understood from the stated protocol objectives and recorded structure, not from outcome details that are absent.

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 Define the PSA Response Rate., measured over At baseline, Day 1, 29, 43, 57, 85, week 18, week 24 & every 12 weeks.

The primary endpoint is the PSA response rate, expressed in the record as a count of participants. PSA is a biomarker; the endpoint description focuses on change from baseline at scheduled assessments. Those assessments were planned at baseline, Day 1, 29, 43, 57, 85, week 18, week 24 and every 12 weeks. The description says that response corresponds to a change from baseline at any of those time points.

In general, a response-rate endpoint reduces individual measurements to a classification: participants either meet a response definition or do not. This can make an outcome easier to summarize and can support a clinically interpretable description if the response threshold and assessment rules are prespecified. The registry record does not report the threshold, the required magnitude or duration of PSA change, or how multiple assessments were combined beyond the phrase “at any” specified time point. Those details are necessary to reproduce the classification.

The record does not report how many participants met the endpoint or the resulting response rate. It also does not describe an uncertainty interval or hypothesis test for this primary outcome. The endpoint is therefore identifiable as an intended measure, but its observed value and precision cannot be assessed from the registry record.

In general, repeated biomarker measurements can capture changes over time that a single measurement might miss. They also require clear rules for timing, missing visits, and which measurement determines response. Those analysis rules are not reported in the registry record, so the intended schedule should not be mistaken for a complete definition of the endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary outcome as a count of participants with a PSA response. It does not report a fitted statistical model or an inferential analysis. The distinctions below explain general statistical concepts relevant to interpreting the stated design and endpoint; they do not describe analyses as having been performed in this study.

What does a response rate summarize?

In general, a response rate is the proportion of an analysis population meeting a defined response rule. That rule needs to specify what change qualifies, which assessments count, and how ambiguous or missing measurements are handled. The registry description says PSA response corresponds to change from baseline at any of the scheduled times, but it does not provide a threshold or full classification rules. Without those details, readers cannot independently determine which participants would count as responders.

The record describes the primary outcome in participant counts, but does not provide the observed responder count or its denominator. A rate cannot be reconstructed from an endpoint title alone. Nor should enrollment automatically be substituted for the analysis denominator: participants may have different availability of post-baseline measurements, and the analysis population is not reported in the registry record.

Why does the single-group structure matter?

In general, a single-group study estimates outcomes within the group observed. A randomized comparison instead contrasts outcomes across groups assigned to different strategies, supporting a more direct estimate of a treatment contrast when allocation and follow-up are appropriately handled. This study is listed as single-group, with allocation recorded as NA and masking as none. The registry does not report a concurrent control arm.

For a single group, change from baseline can be described, but it is not equivalent to a controlled treatment effect. A before-and-after comparison can be influenced by natural changes over time, other care, measurement variation, and who remains available for follow-up. The registry description does not report an analysis that adjusts for such influences. No causal claim should be inferred from an objective or endpoint definition alone.

What does repeated measurement add?

In general, repeated PSA measurements can describe the timing and persistence of biomarker changes. Repeated observations also create analysis choices: a study may use the best observed response, a response at a fixed time, a confirmed response, or another rule. Each choice can classify participants differently. The registry states assessment times from baseline through week 24 and then every 12 weeks, and defines response in relation to any specified time point. It does not report a confirmation rule or a method for combining repeated measurements.

Repeated measurement also raises missing-data questions. A participant who misses a visit may have an unobserved PSA value at that time. In general, treating missing values as no response, excluding them, or using a statistical model can lead to different summaries. The registry record does not state which approach was used. Therefore, the completeness and potential impact of missing PSA measurements cannot be assessed.

How should uncertainty be understood?

In general, estimates from a study have sampling uncertainty: results could vary if a similar study were conducted with a different group of participants. A confidence interval expresses uncertainty around an estimate under a specified method and assumptions. A narrow interval indicates greater precision than a wide interval, though precision does not resolve design limitations such as absence of a comparator. No interval for the primary endpoint is reported in the registry record.

A p-value, when reported, quantifies how incompatible data are with a specified null hypothesis under the analysis assumptions. It is not the probability that a treatment works, and it does not measure clinical importance. No p-value or hypothesis test for PSA response is reported. The stated planning significance level is a design assumption for an illustration, not a result from an analysis.

What do the planning assumptions mean?

The registry record describes a sample-size planning illustration based on a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of the observed effect. It distinguishes event totals for time-to-event planning from participants per arm for other planning settings. These are generic planning assumptions and do not describe the actual single-group allocation in this trial.

In general, sample-size planning asks how much information a future design might need to detect a specified effect under stated assumptions. Planning illustrations are not evidence that the study had a particular probability of detecting an effect after it was conducted. They are not observed power. The assumptions also do not supply an observed effect when the underlying endpoint result is absent. Numerical planning outputs are not reported in the registry record.

Why can event counts and percentages differ in meaning?

Safety summaries may describe whether participants experienced events, while event counts may count multiple occurrences in the same participant. A participant-level count and an event-level count answer different questions. The registry reports participants affected for the broad adverse-event groups and lists selected serious-event terms with percentages. It does not provide further event-count detail or the calculation method for each term percentage in the registry record.

In general, interpretation also depends on the observation period, event definitions, severity grading, and coding. The listed serious-event terms include grades for thrombocytopenia and anemia, but the registry record does not report a full account of ascertainment or exposure time. Safety summaries should therefore be read as recorded descriptive information, not as a comparative estimate of risk.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary endpoint and multiple secondary objectives, including response duration, toxicity, HAHA response, hematological toxicity in relation to bone marrow involvement, survival, and tumor targeting. Considering multiple outcomes or repeated assessment times can raise multiplicity concerns: in general, the more opportunities a study has to identify a nominally notable result, the more important it is to understand whether testing was adjusted or hierarchically planned.

The registry record does not report a multiplicity adjustment, testing hierarchy, or statistical analysis plan. It also does not report inferential analyses for the primary or secondary outcomes. No claim about correction or control of false-positive findings can therefore be made from this record.

The PSA endpoint was to be assessed at baseline, Day 1, 29, 43, 57, 85, week 18, week 24 and every 12 weeks. The description says response may be based on change at any specified time point. The record does not explain how the repeated opportunities were incorporated into the final response classification or any statistical testing.

Missing-data methods are also not reported in the registry record. The record does not state how participants without a post-baseline PSA measurement, missed visits, incomplete follow-up, or withdrawal were handled for the primary endpoint. The number with evaluable data and the analysis population are not reported. Enrollment alone does not answer these questions.

In general, missingness can affect both the denominator and the estimated response, particularly when availability of measurements is related to health status or outcome. Without the analysis rules and completeness information, the direction or magnitude of any such effect cannot be judged. The same limitation applies to secondary outcomes whose follow-up and analysis populations are not described.

11. 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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: thrombocytopenia - grade 4 (8.5%), thrombocytopenia - grade 3 (4.3%), bilateral moderate hydronephrosis (2.1%), chest pain (2.1%), generalized weakness and fatigue (2.1%).

The registry reports 47 participants at risk for serious adverse events, with 9 affected. For other adverse events, it reports 47 at risk and 47 affected. These are participant-level summaries in the adverse-event record; they do not state the number of separate event episodes per participant.

The listed serious-event terms and percentages are thrombocytopenia - grade 4, 8.5%; thrombocytopenia - grade 3, 4.3%; bilateral moderate hydronephrosis, 2.1%; chest pain, 2.1%; generalized weakness and fatigue, 2.1%; and anemia - grade 3, 2.1%. These entries identify selected terms, not necessarily every event recorded. The registry record does not report a complete narrative of event timing, duration, or relationship to treatment.

In general, an adverse-event summary describes events observed and recorded under a study’s monitoring and coding procedures. Without a comparator, it cannot quantify how event occurrence differed from another treatment or from background risk. The registry record does not report a death count. These data should be read as descriptive safety information for the study group, not as a comparative estimate or a recommendation about treatment.

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

The registry record establishes that this was a phase 2, single-group study of 177Lu-J591 in patients with metastatic androgen-independent prostate cancer and that PSA response was the primary outcome. It also gives the planned treatment description and PSA assessment schedule. Those details describe the study’s intent and structure, not the primary result.

The numerical PSA response result is not reported in the registry record. Neither the number meeting the response definition nor the response rate is available in the record. The response threshold, analysis denominator, missing-data handling, and uncertainty interval are also not reported. As a result, the magnitude and precision of the primary outcome cannot be judged from the registry information.

Even if a within-group PSA change were reported, a single-group design would not establish how outcomes would compare with another treatment or with no study treatment. A causal comparison requires an appropriate basis for estimating what would have happened under an alternative. The registry identifies no concurrent comparator group.

The adverse-event record provides participant-level summaries and selected serious-event terms, but those summaries are not a substitute for a full comparative safety assessment. Secondary objectives are listed, while numerical results for them are not reported in the registry record. An objective is not evidence that an outcome occurred or that it favored any particular interpretation.

In general, statistical evidence needs both an estimate and information about its uncertainty, together with a design that supports the question being asked. The available registry information supports a description of the study design, intended endpoints, and recorded adverse-event summaries. It does not support a conclusion about efficacy, comparative benefit, or the treatment’s overall balance of outcomes.

13. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a biomarker endpoint and a treatment comparison. PSA response was the primary endpoint, and the registry gives a schedule for repeated assessments. Yet the study is recorded as single-group, with no randomized comparator. That structure determines what a response summary could establish: it could describe observations within the study group, but it would not by itself estimate a contrast against another strategy.

The record also illustrates why endpoint definitions need operational detail. A response described as change from baseline at any scheduled time sounds straightforward, but reproducible classification depends on rules for the magnitude of change, confirmation, timing, missing measurements, and the analysis denominator. Those rules are not reported in the registry record. Without them, even a numerical count would be difficult to interpret fully.

The distinction between a stated objective and a reported result is equally important. The registry names outcomes spanning PSA response, duration, toxicity, immune response, survival, and tumor targeting. The record does not provide numerical results for most of these aims, and no primary inferential analysis is reported. Careful reading avoids treating planned outcomes as findings.

Finally, the adverse-event summaries demonstrate the limits of descriptive safety data. Counts and listed percentages can identify what was recorded in the study group, but a single-group summary cannot provide a controlled comparison of risk. Statistical interpretation therefore depends not only on the numbers displayed but also on study design, definitions, follow-up, and analysis choices. Several of those details are not reported in the registry record.

14. 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 main limitation for interpreting the primary endpoint is that the registry record states the intended PSA response measure but does not report the observed result. The response threshold and detailed classification rules are also not reported, so the endpoint cannot be reproduced from the description alone.

The single-group design has no concurrent comparator. It can describe outcomes among participants studied but does not directly estimate a treatment contrast. The record also lists no masking. These design features should be considered separately from the question of whether an outcome was measured.

The primary analysis population, number with evaluable PSA data, handling of missed assessments, and missing-data method are not reported in the registry record. The scheduled assessments extend over time, but follow-up completeness and the way repeated measurements were reduced to a response classification are not described.

No inferential analyses, confidence interval, or p-value for the primary endpoint are reported. The registry record also does not report a statistical analysis plan, multiplicity strategy, interim analysis approach, or sample-size justification for the actual trial. The planning assumptions described for an illustration should not be interpreted as the trial’s design or as observed power.

Numerical results for the listed secondary objectives are not reported in the registry record. The safety information includes participant-level summaries and selected serious-event terms, but the record does not provide a death count or further detail on event ascertainment, follow-up duration, or treatment attribution. These omissions limit assessment of both outcome completeness and the precision of safety interpretation.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Treatment With Radiolabeled Monoclonal Antibody HuJ591-GS (177Lu-J591) in Patients With Metastatic Prostate Cancer — NCT00195039.
• Registry record last updated 2017-10-05; status last verified 2017-09.
• Results first posted 2017-10-05.
• 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.

18. Record Summary

NCT00195039 is a completed phase 2, single-group study sponsored by Weill Medical College of Cornell University. The registry records a start of 2004-08, primary completion in 2012-02, and enrollment of 47. The study concerned 177Lu-J591 in patients with metastatic androgen-independent prostate cancer.

The intervention description specifies a single dose of 65 or 70 mCi/m2 and a total antibody dose of 20 mg. The primary endpoint was PSA response, described as change from baseline at specified assessment times. The numerical primary result, its analysis denominator, and inferential analysis are not reported in the registry record.

The registry lists secondary objectives related to response duration, toxicity, HAHA response, hematological toxicity, survival, and tumor targeting. It reports serious adverse events affecting 9 participants among 47 at risk and other adverse events affecting 47 among 47 at risk, with selected serious-event terms and percentages. The record does not report a death count.