This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Phase 3, Randomized, Double-blind, Placebo-controlled Study For Subjects With Locally-advanced Unresectable or Metastatic Synovial Sarcoma (V943-003, IMDZ-04-1702) (NCT03520959), a randomized phase 3 study. The primary outcome is Progression-Free Survival (PFS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03520959 |
| Phase | Phase 3 |
| Condition | Synovial Sarcoma, Cancer, Soft Tissue Sarcoma |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Immune Design, a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA) |
| Results posted | Yes |
2. Clinical Question
Population
Participants with unresectable locally advanced or metastatic NY-ESO-1+ synovial sarcoma following first-line systemic anti-cancer therapy.
Intervention
A sequential regimen of LV305 and G305, identified as CMB305.
Comparator
A sequential regimen of LV305-matching placebo and G305-matching placebo.
Primary question
Whether progression-free survival, measured from randomization to investigator-determined disease progression or death, differed between the CMB305 and placebo groups.
The registry describes a Phase 3 trial intended to assess the efficacy and safety of CMB305 in participants with the specified sarcoma after first-line systemic anti-cancer therapy. Its brief summary says the study was intended to assess whether the vaccine regimen might help the immune system slow or stop tumor growth and improve survival. The primary endpoint was progression-free survival (PFS), defined using RECIST v1.1 and based on investigator-determined progression or death, whichever came first.
That intended question cannot be answered from the posted primary-outcome data: the registry explicitly states that no data were collected or analyzed for PFS because the study ended early. The record lists enrollment as 1, but does not report participant-level endpoint observations, a group comparison, or an effect estimate. The study’s intended comparison is therefore clear, while its clinical result is not estimable from the registry record.
3. Trial Design
This was a randomized, quadruple-masked, parallel-group Phase 3 study with CMB305 and placebo groups. The CMB305 regimen consisted of sequential LV305 and G305; the placebo group received sequential LV305-matching and G305-matching placebos. The registry identifies the study as placebo-controlled and records randomized allocation. It does not report the allocation procedure or the operational details of masking, so those details cannot be characterized further.
The intended population was participants with unresectable locally advanced or metastatic NY-ESO-1+ synovial sarcoma following first-line systemic anti-cancer therapy. The primary outcome was PFS from randomization to investigator-determined disease progression or death, assessed up to 24 months. Secondary outcomes included time to next treatment, distant metastasis-free survival, overall response rate, treatment-emergent adverse events, quality of life using EQ-5D-5L and EQ-5D-Y questionnaires, and discontinuations due to adverse events.
The registry reports enrollment of 1 and status as terminated. The recorded start date is 2018-09-18 and the primary completion date is 2018-11-20. These dates and the enrollment entry do not establish how many participants were randomized, treated, or evaluable in either group; those details are not reported in the registry record. The reason for termination and the timing or process behind the decision are also not reported. No outcome analyses are listed.
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
| Stage | Placebo | CMB305 |
|---|---|---|
| STARTED | 0 | 1 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 0 | 1 |
Reasons for not completing this period:
| Reason | Placebo | CMB305 |
|---|---|---|
| Study terminated by Sponsor | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: No data were collected or analyzed for this outcome measure due to early termination of the 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.
Population: 0 participants are reported due to the risk of identification of a person.
| Characteristic | Unit | Placebo | CMB305 | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 0 | 0 | |
| Age, Categorical: <=18 years | — | — | — | |
| Age, Categorical: Between 18 and 65 years | — | — | — | |
| Age, Categorical: >=65 years | — | — | — | |
| Sex: Female, Male: Female | — | — | — | |
| Sex: Female, Male: Male | — | — | — | |
| Ethnicity (NIH/OMB): Hispanic or Latino | — | — | — | |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | — | — | — | |
| Ethnicity (NIH/OMB): Unknown or Not Reported | — | — | — | |
| Race (NIH/OMB): American Indian or Alaska Native | — | — | — | |
| Race (NIH/OMB): Asian | — | — | — | |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | — | — | — | |
| Race (NIH/OMB): Black or African American | — | — | — | |
| Race (NIH/OMB): White | — | — | — | |
| Race (NIH/OMB): More than one race | — | — | — | |
| Race (NIH/OMB): Unknown or Not Reported | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as Progression-Free Survival (PFS), measured over From randomization to investigator-determined date of disease progression or death, assessed up to 24 months..
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
PFS measures the time from randomization until the first of investigator-determined disease progression or death. The registry defines progression using Response Evaluation Criteria in Solid Tumors (RECIST v1.1) and gives an assessment timeframe of up to 24 months. In general, a time-to-event endpoint can capture both how long participants remain alive without documented progression and the timing of events, rather than reducing follow-up to a simple status at one visit.
Such an endpoint is commonly used in cancer trials because progression and death are clinically important events and may occur at different times for different participants. Its interpretation depends on how progression is assessed, how follow-up and censoring are handled, and which participants contribute to the analysis. Those statistical details are not reported in the registry record.
Here, the registry explicitly states that no PFS data were collected or analyzed because of early termination. There is consequently no reported PFS estimate, comparison between groups, uncertainty interval, or inferential test to interpret. The endpoint definition describes the intended measurement, not an observed treatment result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical fact is the absence of primary-outcome data. Although the registry identifies PFS as the primary endpoint and defines it in terms of progression or death, it states that no data were collected or analyzed for that outcome because the study terminated early. The record also lists zero analyses. There is no posted estimate of PFS in either group and no treatment contrast, confidence interval, or p-value for the primary comparison.
Enrollment is listed as 1. This is not enough to reconstruct a randomized comparison or determine how many participants, if any, received each regimen. The record does not report group-specific enrollment, treatment exposure, follow-up, event counts, or analysis populations. Therefore, the enrollment entry should not be read as a usable sample for estimating comparative efficacy.
The registry includes zero participants at risk and zero affected for the listed adverse-event categories in both groups. In the context of the explicit statement that the study ended early and did not collect or analyze PFS data, these entries do not establish that treatment caused no adverse events. Without information on exposure, ascertainment, reporting completeness, and the population included in safety summaries, zero entries cannot support a reliable safety comparison. The record also lists no top serious adverse-event terms.
The trial’s design and planned outcomes describe what investigators intended to study, but they do not supply evidence of what happened to participants. There is no basis in the registry record to estimate whether PFS differed, how large any difference might have been, or how precisely an effect was measured. Likewise, the absence of reported analyses does not show that the regimens were equivalent; equivalence would require a suitable design and outcome evidence, neither of which is reported as a result.
The registry’s planning assumptions refer to a two-sided significance level of 0.05, equal allocation, and a normal approximation. These are design assumptions, not findings. No observed effect is available to anchor the stated sample-size illustration, and no analysis results are posted. Accordingly, no power or sample-size conclusion about the completed trial can be drawn from those assumptions. The data support a description of the intended design and the early termination, but not an efficacy or comparative safety conclusion.
9. Statistical Methods Explained
What would a PFS comparison estimate?
In general, time-to-event analysis uses both whether an event occurred and the time at which it occurred. For this study, the event was the first investigator-determined disease progression or death after randomization. A comparison between groups would usually summarize the relative event experience over follow-up, while accounting for participants whose event time is not observed before follow-up ends. The registry record does not report a PFS estimate or the method used to analyze such times. Since it states that no PFS data were collected or analyzed, there is no estimate to interpret.
A confidence interval, in general, describes the range of effect values compatible with the observed data under a specified statistical procedure. Its width reflects precision: narrower intervals indicate greater precision, while wider intervals indicate greater uncertainty. No confidence interval for the primary comparison is reported. A p-value, if reported, would address compatibility of data with a specified null hypothesis under an analysis model; it would not by itself quantify clinical importance. No PFS p-value is reported either.
What do randomization and masking contribute?
In general, random allocation aims to make comparison groups similar with respect to measured and unmeasured prognostic factors, on average. Masking can reduce the influence of knowledge about treatment assignment on participant experience, clinical care, outcome assessment, and reporting. The registry classifies allocation as randomized and masking as quadruple, but does not report the allocation sequence, concealment process, or which roles were masked. These design labels describe intended safeguards; they cannot compensate for the absence of outcome observations.
A parallel-group design assigns participants to a regimen and compares outcomes between groups over the study period. Here, the identified groups were CMB305 and placebo. The record gives no group-specific participant counts or treatment exposure. Consequently, it is not possible to check whether the intended allocation was achieved or to characterize the groups’ baseline balance.
How should event-time assumptions be understood?
In general, time-to-event methods rely on assumptions about event measurement, follow-up, and censoring. Censoring occurs when the event time is not observed during a participant’s available follow-up; valid interpretation typically requires that the censoring process be handled appropriately by the analysis. The registry does not report censoring rules, follow-up distributions, event counts, or a statistical model for PFS. It also does not report whether assessments were scheduled at particular intervals or how missing assessments were handled. No assumptions about those procedures can be inferred from the endpoint definition alone.
The registry states that PFS was to be assessed up to 24 months. That describes the stated timeframe, not the actual duration of observation for any participant. The record supplies no PFS observations from which to assess event timing, censoring, or the stability of a model-based comparison.
What do the planning assumptions mean?
In general, a sample-size calculation asks how many participants or events would be needed to detect a specified effect under stated assumptions. The record describes an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It also distinguishes event totals for time-to-event outcomes from participants per arm for other outcomes. These assumptions describe a planning framework; they are not an analysis of trial results and do not establish that the trial had adequate power.
No observed PFS effect is reported, and the registry says no data were collected or analyzed for that outcome. Thus there is no effect value from which to interpret the proposed illustration. The record also does not report the trial’s own sample-size justification, target enrollment, or design assumptions. Any sample-size result tied to an unavailable observed effect would not provide a valid account of the trial’s planned or achieved power. In general, post hoc power calculations based on an observed effect are not a substitute for an estimate with its uncertainty, and sample-size illustrations should not be described as observed power.
Why does early termination matter analytically?
Early termination can leave too little outcome information for a planned analysis, but the reasons and consequences depend on the circumstances. The registry records termination and says no data were collected or analyzed for PFS. It does not report the reason for stopping, whether any interim analysis took place, or whether termination was related to efficacy, safety, recruitment, or another consideration. None of those explanations should be assumed.
With no reported endpoint observations, the usual statistical tasks—estimating a group contrast, quantifying uncertainty, assessing model assumptions, and examining sensitivity to missingness—cannot be carried out from this record. The study design identifies an intended comparison, but a randomized design alone does not generate a result. A result requires outcome data and a reported analysis, neither of which is available for PFS.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists PFS as the primary outcome and several secondary outcomes, including time to next treatment, distant metastasis-free survival, overall response rate, adverse events, quality of life, and discontinuation due to adverse events. It does not report a statistical testing hierarchy, multiplicity adjustment, or a plan for controlling the chance of false-positive findings across outcomes. Those elements are not reported in the registry record.
In general, multiplicity arises when multiple outcomes, time points, subgroups, or statistical tests are examined. Testing many hypotheses can increase the chance that at least one result appears statistically notable by chance. A prespecified hierarchy or adjustment can help define how such results should be interpreted. Here, no outcome analyses are listed, so there are no reported inferential findings whose multiplicity can be assessed. The intended list of outcomes alone does not show how they would have been tested or prioritized.
Missing-data procedures are also not reported. In general, missing outcomes can affect estimates when the availability of data is related to prognosis, treatment, or other factors. PFS analyses may also require rules for censoring and handling incomplete assessments. The registry does not describe imputation, censoring, sensitivity analyses, or methods for incomplete follow-up. Since it explicitly reports that no PFS data were collected or analyzed, there is no basis for evaluating the impact of missingness on a PFS estimate.
The analysis populations are not reported in the registry record. It is therefore unclear which participants would have been included in efficacy or safety analyses, and whether the intended population was defined by randomization, treatment received, or evaluability. No inference should be made about these choices from the randomized designation alone. The absence of reported populations and procedures prevents assessment of how the planned analysis would have connected enrollment, treatment exposure, and outcomes.
11. What the Result Does, and Does Not, Mean
The registry record establishes that the trial was designed as a randomized, quadruple-masked, parallel comparison of CMB305 with matching placebo in a specified synovial sarcoma population. It identifies PFS as the primary outcome and defines the event as investigator-determined progression or death. It also records early termination and states directly that no PFS data were collected or analyzed.
These registry entries do not show whether CMB305 improved, worsened, or had the same effect on PFS relative to placebo. No group-specific outcome estimates, comparative effect, confidence interval, or p-value is posted. The lack of an estimate is not evidence that the groups had equal outcomes, nor does it establish that a clinically important effect was absent. It means the registry record does not contain outcome evidence with which to answer the primary question.
The reported enrollment of 1 does not resolve this gap. The record does not say how many participants were randomized, which group they entered, whether they received study treatment, or whether any follow-up outcomes were available. Likewise, the zero entries in the adverse-event group summaries should not be interpreted as evidence that no adverse events occurred, given the absence of reported exposure and the study’s early termination.
General explanations of trial design and statistical methods describe how the intended comparison could be analyzed if suitable data existed. They do not create evidence or compensate for missing results. The registry record also does not report why the trial ended, whether interim analyses were performed, or how missing observations and analysis populations would have been handled. These uncertainties limit interpretation of both the conduct and the statistical meaning of termination.
The defensible conclusion is narrow: the record documents the intended comparison and the absence of analyzed primary-outcome data. It cannot support a conclusion about efficacy, comparative safety, or equivalence.
12. Why This Trial Matters Statistically
This trial illustrates a basic distinction in clinical research: a protocol question and a trial result are not the same thing. Randomization, masking, a placebo comparator, and a defined primary endpoint describe the planned approach to answering a question. They do not establish an answer when outcome data are absent. For statistical interpretation, the lack of an estimate is itself consequential because it prevents assessment of both the direction and precision of a treatment contrast.
The registry makes this limitation especially clear by stating that no PFS data were collected or analyzed because of early termination. It also lists enrollment as 1 and reports no analyses. Those entries make it important not to treat the planned Phase 3 design as evidence that a comparative efficacy analysis was completed. A large or advanced trial label does not replace observed outcomes.
The record also demonstrates why safety summaries require context. Zero counts in a registry group summary are not automatically proof of zero harm when participant exposure, ascertainment, and analysis populations are not described. Statistical reporting should make the denominator and observation process clear enough for readers to interpret counts; those details are not reported.
For biostatisticians and clinical researchers, the case underscores the value of transparent reporting about termination, data collection, endpoint availability, and analysis procedures. The registry records the study’s intended endpoints and status, but does not explain the reason for termination or the disposition of participants. That absence limits conclusions and prevents evaluation of how the study might have reached a result. Sound interpretation therefore depends on separating design intent from analyzed evidence and being explicit about what remains unknown.
13. 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 trial-specific limitation is that no PFS data were collected or analyzed after early termination. The registry therefore contains no primary-outcome estimate or comparison. Although the record reports enrollment of 1, it does not report participant disposition, group-specific enrollment, treatment receipt, follow-up, or evaluable populations. The relationship between the enrollment entry and the intended randomized comparison cannot be determined from the registry record.
The reason for termination is not reported in the registry record. Nor does the record report whether interim analyses occurred, whether the study stopped for a prespecified reason, or whether the termination decision was connected to efficacy, safety, recruitment, or another factor. No explanation should be inferred from the termination status or dates alone.
Statistical details needed to interpret a completed analysis are also absent: the planned analysis model, censoring rules, missing-data methods, analysis populations, multiplicity strategy, and sample-size justification are not reported. The registry lists secondary outcomes, but does not provide their analyzed results. For adverse events, the group summaries list zero participants at risk and zero affected, but exposure and ascertainment details are unavailable. Those entries cannot establish the absence of adverse events.
Finally, the registry’s stated PFS timeframe of up to 24 months is a planned assessment window, not evidence that participants were followed for that duration. The lack of observations means precision, bias, and sensitivity to analytic assumptions cannot be evaluated for the primary endpoint.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: A Phase 3, Randomized, Double-blind, Placebo-controlled Study For Subjects With Locally-advanced Unresectable or Metastatic Synovial Sarcoma (V943-003, IMDZ-04-1702) — NCT03520959.
- Registry record last updated 2020-04-16; status last verified 2020-04.
- Results first posted 2020-04-16.
- 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.
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17. Record Summary
The registry describes NCT03520959 as a randomized, quadruple-masked, parallel-group Phase 3 study comparing CMB305 with matching placebo in participants with unresectable locally advanced or metastatic NY-ESO-1+ synovial sarcoma following first-line systemic anti-cancer therapy. CMB305 was a sequential LV305 and G305 regimen; placebo used matching components.
The primary outcome was PFS, defined from randomization to investigator-determined progression or death using RECIST v1.1, with assessment up to 24 months. Secondary outcomes included treatment timing, response, safety, and quality-of-life measures. The record lists enrollment as 1, status as terminated, and no analyses. It states that no PFS data were collected or analyzed because the study ended early. The reason for termination and detailed statistical procedures are not reported in the registry record, so no comparative efficacy or safety conclusion can be drawn.