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 ONC201 in Recurrent/Refractory Metastatic Breast Cancer and Advanced Endometrial Carcinoma (NCT03394027), a na phase 2 study. The primary outcome is Cohort 1 - Progression-free Survival (PFS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03394027 |
| Phase | Phase 2 |
| Condition | Triple Negative Breast Cancer, Endometrial Cancer, Hormone Receptor Positive, HER2 Negative Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | National Cancer Institute (NCI) |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled adults with recurrent or refractory metastatic breast cancer or advanced endometrial cancer. The breast cancer cohorts included hormone receptor-positive disease and triple-negative disease; the endometrial cancer cohort included female participants only. The eligibility description specifies adults ages 18 and older with metastatic breast cancer or metastatic endometrial cancer. The primary endpoint description focuses on participants with refractory, metastatic hormone receptor-positive breast cancer, and states that 7/10 participants were analyzed because 3 participants were ineligible.
Intervention
Participants received ONC201, an oral study drug taken once every 7 days. Treatment was organized in 28-day cycles. The study description also refers to tumor biopsies before treatment and after 5 weeks taking the study drug, along with periodic assessments.
Comparator
There was no concurrent control group described. The study used a single-group model and was not a randomized comparison. The registry record therefore does not provide a like-for-like control arm for estimating a treatment contrast.
Primary question
The primary endpoint asked how long participants in the hormone receptor-positive breast cancer cohort remained alive without disease progression after starting treatment, using the registry definition based on RECIST. The record identifies the endpoint as median progression-free survival in months, but the median result and its full range are not reported in the registry record.
The broader objective was to assess whether ONC201 was associated with tumor shrinkage and whether that effect was maintained. The study also listed outcomes for serious and non-serious adverse events, response and clinical benefit, and progression-free survival in other cohorts. These are distinct questions: tumor response concerns change in measurable disease, while progression-free survival concerns the time until progression or death. A single-group study can describe outcomes among treated participants, but without a concurrent comparator it cannot isolate the effect of treatment from other explanations for observed outcomes.
3. Trial Design
This was a phase 2, single-group study of ONC201 in recurrent or refractory metastatic breast cancer and advanced endometrial cancer. The registry lists enrollment of 30 and a completed status. The recorded study start was 2018-01-17, and the primary completion date was 2021-03-18. The record describes one treatment arm divided into three cohorts: estrogen receptor-positive breast cancer, triple-negative breast cancer, and endometrial cancer.
Participants took ONC201 by mouth once every 7 days. The study was organized in 28-day cycles, with recurring clinical assessments. The description includes medical history, physical examination, heart, blood, and urine tests, CT and bone scans, and review of medical records and tumor samples. It also describes tumor biopsies before treatment and after 5 weeks taking the study drug. Participants kept a diary of dosing and side effects; weekly calls during cycle 1 are mentioned in the available description, which ends before the call schedule is fully described.
The primary endpoint was progression-free survival in Cohort 1, the hormone receptor-positive breast cancer cohort. Its definition was time from treatment start to progression or death, whichever occurred first, assessed using RECIST. The registry says assessment occurred every 8 weeks while on trial and that participants were followed for an average of 8-10 weeks, up to 16 weeks. The primary endpoint population statement says 7/10 participants were analyzed because 3 participants were ineligible.
Other listed outcomes included serious and non-serious adverse events in all three cohorts, overall response rate in Cohort 1, clinical benefit in the cohorts, and progression-free survival in Cohorts 2 and 3. The registry record does not describe a randomized allocation or masking; it explicitly identifies a single-group model and no masking. No concurrent comparison group is described, so outcomes across the disease cohorts should not be treated as though they came from randomized treatment arms.
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 | Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | Cohort 2-Triple Negative Breast Cancer (Male and Female) | Cohort 3-Endometrial Cancer (Female Only) |
|---|---|---|---|
| STARTED | 10 | 6 | 14 |
| COMPLETED | 7 | 5 | 10 |
| NOT COMPLETED | 3 | 1 | 4 |
Reasons for not completing this period:
| Reason | Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | Cohort 2-Triple Negative Breast Cancer (Male and Female) | Cohort 3-Endometrial Cancer (Female Only) |
|---|---|---|---|
| Ineligible | 3 | 1 | 3 |
| Participant declined to participate before treatment started | 0 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: 7/10 participants were analyzed because 3 participants were ineligible.
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.
| Characteristic | Unit | Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | Cohort 2-Triple Negative Breast Cancer (Male and Female) | Cohort 3-Endometrial Cancer (Female Only) | Total |
|---|---|---|---|---|---|
| Participants analysed | 10 | 6 | 14 | 30 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 8 | 6 | 8 | 22 |
| Age, Categorical: >=65 years | Participants | 2 | 0 | 6 | 8 |
| Age, Continuous | years | 60.14 (SD 6.25) | 53.88 (SD 8.37) | 63.65 (SD 8.99) | 60.53 (SD 8.62) |
| Sex: Female, Male: Female | Participants | 10 | 6 | 14 | 30 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 0 | 0 | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 8 | 5 | 13 | 26 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 | 1 | 1 | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 1 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 1 | 0 | 1 |
| Race (NIH/OMB): Black or African American | Participants | 1 | 3 | 2 | 6 |
| Race (NIH/OMB): White | Participants | 8 | 2 | 11 | 21 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 0 | 1 |
| Region of Enrollment: United States | participants | 10 | 6 | 14 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Cohort 1 - Progression-free Survival (PFS), measured over Every 8 weeks, while on the Trial. Participants were followed for an average of 8-10 weeks (up to 16 weeks)..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | Months |
| Endpoint classification | Time-to-Event Analysis |
Progression-free survival (PFS) measures the time from treatment start until disease progression or death, whichever occurs first. In this study, the primary PFS endpoint concerned participants with refractory, metastatic hormone receptor-positive breast cancer. Progression was defined using RECIST: at least a 20% increase in the sum of the diameters of target lesions, or the appearance of one or more new lesions. The endpoint was assessed every 8 weeks while participants remained on trial.
Time-to-event endpoints are useful when the timing of an event matters and participants may be followed for different lengths of time. A median summarizes the point by which half of the observed event-time distribution has been reached, subject to the analysis method and available follow-up. The registry specifies median PFS in months and full range as the planned summary. However, the median and range are not reported in the registry record. Without those results, the endpoint definition can be described, but the observed duration of PFS cannot be interpreted from this record.
PFS is not the same as tumor response. Response concerns whether measurable tumors meet criteria for shrinkage, while PFS includes the time until progression or death. It is also not a direct comparison of ONC201 with another treatment in this study, because the trial had a single-group design. General statistical context: censoring can occur when a participant's event time is not observed during follow-up; interpretation of a time-to-event estimate depends on how follow-up and censoring are handled. The registry record does not report the censoring details or the statistical method used to calculate the primary estimate.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive limitation is that the registry record names the primary endpoint but does not report its numerical result. It identifies median PFS as the endpoint, gives months as the unit, specifies full range as the dispersion summary, and describes assessment timing. It also states that 7/10 participants were analyzed because 3 participants were ineligible. But the median, range, and any uncertainty interval are not reported in the registry record. Thus, the posted record does not establish the observed PFS duration or its precision.
The study is described as a phase 2 single-group investigation, with separate disease cohorts receiving ONC201. Such a design can document outcomes observed in participants who received the intervention. It does not provide a randomized control group that would help distinguish treatment-associated outcomes from the natural course of disease, participant selection, other care, or measurement variation. The record itself flags that this was not a randomized comparison and that arms are not a like-for-like control comparison. In this trial there is one treatment arm divided into cohorts, not distinct treatment-versus-control arms.
The adverse-event fields provide cohort counts for participants at risk and affected by serious and other adverse events, together with death counts. The registry lists serious adverse events affecting 4 of 7 at risk in Cohort 1, 3 of 5 in Cohort 2, and 5 of 10 in Cohort 3. The other adverse-event fields list 7 of 7, 5 of 5, and 10 of 10, respectively. Death counts are 2, 1, and 2, respectively. These are descriptive counts; the registry information does not establish whether an event or death was caused by ONC201. The record lists abdominal pain, anemia, breast pain, dyspnea, fever, and nausea among the top serious adverse-event terms, each at 20.0%.
These event counts should be read alongside cohort size and follow-up, not as evidence of comparative risk. Cohorts differ by cancer type, and there is no concurrent comparator. The record does not report exposure-adjusted event rates, detailed event timing, or causal attribution. It also does not provide the primary PFS result or reported response results. Consequently, the available information supports a description of study structure and recorded safety counts, but not a conclusion about relative benefit, harm, or treatment effect.
General statistical context: an estimate is more informative when accompanied by an uncertainty interval, because the interval communicates how imprecisely the underlying quantity is estimated. No confidence interval for the primary PFS result appears in the registry record. Absence of a reported estimate is not evidence that the endpoint was zero or that no events occurred; it means the primary result cannot be quantified from the record.
9. Statistical Methods Explained
The registry describes an intervention study with a single-group model, no masking, and no randomized allocation. These design features matter for interpreting the data. A single-group trial can describe outcomes among participants who received the study drug, but it does not estimate a randomized contrast against a concurrent control. Cohort differences also reflect different cancer types rather than assigned treatment strategies. The record explicitly cautions that this is not a randomized comparison and that arms are not a like-for-like control comparison.
What does median progression-free survival summarize?
Median PFS is a time-to-event summary. Each participant's outcome is the time from treatment start until progression or death, whichever happens first, according to the endpoint definition. The median describes the middle of the event-time distribution, rather than an average change in tumor size or a proportion responding. The registry specifies months as the unit and full range as the dispersion summary. It does not report the median or range, so these quantities cannot be interpreted from the posted record.
General statistical explanation: time-to-event methods can include participants whose event has not been observed by the end of their available follow-up. Such observations are censored rather than treated as though the event occurred at the last contact. The estimated event-time distribution depends on event and censoring information and on the analysis procedure. The registry record does not state the method used for the PFS estimate, how censoring was handled, or the number of progression or death events contributing to the primary analysis.
Why does the RECIST definition matter?
The registry defines progression as at least a 20% increase in the sum of target-lesion diameters or the appearance of one or more new lesions. A standardized measurement rule helps make disease assessments more consistent than an informal judgment. It also makes clear that PFS is linked to a defined progression event, not simply any change in symptoms or a tumor's size. The record says assessments were scheduled every 8 weeks while participants were on trial. The timing of assessments is relevant because progression is generally identified at an assessment, and the observed event time may therefore reflect the assessment schedule. This is general methodological context; the registry does not provide further detail about how assessment dates were used in the analysis.
What can cohort counts tell the reader?
The record separates outcomes by hormone receptor-positive breast cancer, triple-negative breast cancer, and endometrial cancer. This grouping is clinically descriptive, but it does not create a randomized comparison. The primary endpoint population statement says 7/10 participants were analyzed because 3 participants were ineligible. That statement identifies a difference between the cohort count and the analyzed population for the primary endpoint, but it does not explain the eligibility criteria that led to exclusion or describe any other analysis populations.
For adverse events, the record lists participants at risk and affected in each cohort. These counts describe how many participants were recorded with events; they do not indicate event rates per unit of treatment exposure. General statistical context: event counts can be influenced by the amount of time participants are observed and by differences in underlying disease or health status. Exposure-adjusted rates and a comparator may help with some comparisons, but neither is reported as a basis for the figures in this record.
What is the role of hazard ratios?
A hazard ratio is a relative measure of event rates over time between groups under a time-to-event model. It is usually interpreted in relation to a defined comparison and its assumptions. This study is single-group, and the registry record does not report a hazard-ratio value for the primary endpoint. The record notes that only sponsor-reported hazard ratios are used for time-to-event content, but no such numerical result is included in the information available for this analysis. A hazard ratio should not be inferred from a median or from cohort counts.
How should planning calculations be distinguished from trial results?
The registry describes planning assumptions for an illustration based on the observed effect: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that time-to-event calculations concern total events, while other calculations concern participants per arm. Those assumptions describe a planning exercise, not the observed design of this single-group study. Any sample-size figures generated under those assumptions would be planning illustrations, not observed power and not evidence that the trial had a particular probability of detecting an effect. The registry record does not report a protocol sample-size justification, and no numerical planning outputs are included in the record details used for this explanation.
General statistical context: over-dispersion means that outcome variability is greater than a model expects. When present, a model that ignores it can understate uncertainty and make estimates look more precise than warranted. The registry information does not identify an over-dispersion analysis for this study, and this is not a reported feature of the primary time-to-event endpoint. It is therefore a general concept rather than a claim about the trial's analysis.
10. Multiplicity, Missing Data and Analysis Populations
The study lists several outcomes across three disease cohorts: serious and non-serious adverse events, overall response rate in Cohort 1, clinical benefit across the cohorts, and PFS in Cohorts 2 and 3, in addition to the primary PFS endpoint in Cohort 1. When many outcomes are examined, multiplicity can arise because repeated tests increase the chance of at least one apparently notable result by chance. A prespecified strategy can address that issue, for example by defining a primary hypothesis or adjusting inference across tests. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting the secondary outcomes.
The record lists no analyses. It does not report p-values, confidence intervals, or numerical results for the primary PFS endpoint. It also does not report the planned statistical analysis methods, interim analyses, or a protocol-based sample-size justification. Those items are not reported in the registry record; their absence should not be filled in by assuming a conventional approach.
For the primary endpoint, the record states that 7/10 participants were analyzed because 3 participants were ineligible. This gives a reason for the difference between the stated cohort and the analyzed population, but does not specify whether eligibility was determined before treatment, whether all remaining participants had complete follow-up, or how missing endpoint data were handled. The record does not describe an intention-to-treat population, a per-protocol population, or sensitivity analyses for missing data. It also does not report how many participants were censored or the reasons for censoring.
General statistical context: missing outcomes can affect an estimate when the availability of data is related to participants' health status or event risk. Clear reporting of analysis populations, missingness, censoring, and sensitivity analyses helps readers judge whether an estimate may be affected. Those details are not reported in the registry record, and no direction or size of any possible bias can be inferred.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | 4 | 7 | 57.1% |
| Cohort 2-Triple Negative Breast Cancer (Male and Female) | 3 | 5 | 60.0% |
| Cohort 3-Endometrial Cancer (Female Only) | 5 | 10 | 50.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | 2 of 7 |
| Cohort 2-Triple Negative Breast Cancer (Male and Female) | 1 of 5 |
| Cohort 3-Endometrial Cancer (Female Only) | 2 of 10 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | 7 of 7 |
| Cohort 2-Triple Negative Breast Cancer (Male and Female) | 5 of 5 |
| Cohort 3-Endometrial Cancer (Female Only) | 10 of 10 |
Most frequent serious adverse event terms
| Event term | Organ system | Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | Cohort 2-Triple Negative Breast Cancer (Male and Female) | Cohort 3-Endometrial Cancer (Female Only) |
|---|---|---|---|---|
| Neoplasms benign, malignant and unspecified (incl cysts and polyps) - Other, Death | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 7 | 1 of 5 | 1 of 10 |
| Abdominal pain | Gastrointestinal disorders | 1 of 7 | 1 of 5 | 0 of 10 |
| Pain | General disorders | 1 of 7 | 0 of 5 | 1 of 10 |
| Sepsis | Infections and infestations | 0 of 7 | 1 of 5 | 1 of 10 |
| Anemia | Blood and lymphatic system disorders | 0 of 7 | 1 of 5 | 0 of 10 |
| Atrial flutter | Cardiac disorders | 0 of 7 | 0 of 5 | 1 of 10 |
| Breast pain | Reproductive system and breast disorders | 0 of 7 | 1 of 5 | 0 of 10 |
| Cardiac arrest | Cardiac disorders | 0 of 7 | 0 of 5 | 1 of 10 |
| Dehydration | Metabolism and nutrition disorders | 0 of 7 | 0 of 5 | 1 of 10 |
| Diarrhea | Gastrointestinal disorders | 0 of 7 | 0 of 5 | 1 of 10 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Cohort 1-Hormone Receptor (HR) + Breast Cancer (Male and Female) | Cohort 2-Triple Negative Breast Cancer (Male and Female) | Cohort 3-Endometrial Cancer (Female Only) |
|---|---|---|---|---|
| Fatigue | General disorders | 3 of 7 | 1 of 5 | 6 of 10 |
| Aspartate aminotransferase increased | Investigations | 4 of 7 | 1 of 5 | 4 of 10 |
| Lymphocyte count decreased | Investigations | 3 of 7 | 1 of 5 | 4 of 10 |
| Alanine aminotransferase increased | Investigations | 3 of 7 | 1 of 5 | 3 of 10 |
| Alkaline phosphatase increased | Investigations | 2 of 7 | 1 of 5 | 4 of 10 |
| Anemia | Blood and lymphatic system disorders | 2 of 7 | 3 of 5 | 2 of 10 |
| Nausea | Gastrointestinal disorders | 3 of 7 | 2 of 5 | 2 of 10 |
| Anorexia | Metabolism and nutrition disorders | 4 of 7 | 0 of 5 | 1 of 10 |
| Constipation | Gastrointestinal disorders | 3 of 7 | 1 of 5 | 1 of 10 |
| Diarrhea | Gastrointestinal disorders | 2 of 7 | 0 of 5 | 3 of 10 |
Serious events with the highest arm-level rate: abdominal pain (20.0%), anemia (20.0%), breast pain (20.0%), dyspnea (20.0%), fever (20.0%).
The safety record reports cohort-specific counts of participants at risk and affected. For serious adverse events, the listed counts are 4 of 7 in Cohort 1, 3 of 5 in Cohort 2, and 5 of 10 in Cohort 3. For other adverse events, the listed counts are 7 of 7, 5 of 5, and 10 of 10, respectively. The deaths field lists 2 in Cohort 1, 1 in Cohort 2, and 2 in Cohort 3. These are descriptive registry counts, not comparisons against an untreated or alternative-treatment group.
The registry lists abdominal pain, anemia, breast pain, dyspnea, fever, and nausea among the top serious adverse-event terms, each at 20.0%. The record does not specify in this information whether each term occurred in a particular cohort or provide event-level timing, severity detail beyond the listed serious-event category, or attribution to treatment. The death counts likewise do not establish cause.
General statistical context: a participant count and an event count are not necessarily interchangeable, because one participant may experience more than one event. Counts also do not account for differences in time on treatment or duration of follow-up. The registry record does not provide exposure-adjusted rates for these outcomes. Without a comparator and fuller event detail, these figures describe what was recorded but do not establish whether ONC201 increased or decreased risk.
12. What the Result Does, and Does Not, Mean
The registry record describes a completed phase 2, single-group study of ONC201 in three cohorts with different metastatic cancers. It provides the primary endpoint definition, the assessment schedule, a primary endpoint population statement, and cohort-specific adverse-event counts. These details help define what the study intended to measure and which participants were included in the primary endpoint analysis.
The record does not report the numerical primary PFS result. Although it identifies median PFS in months and full range as the summary, neither the median nor range is available in the registry record. No confidence interval or other measure of uncertainty is reported for that endpoint. Consequently, the available information does not show the observed PFS duration or how precisely it was estimated. The record also lists secondary outcomes but does not give their numerical results in the registry record used for this account.
The study's single-group design means that outcomes among ONC201 recipients cannot be contrasted with outcomes in a concurrent control group. Even if a numerical outcome were reported, a single-group result alone would not establish what would have happened to comparable participants without ONC201 or under another treatment. The cohorts represent different cancer types, so differences among them would not be a randomized treatment comparison.
The adverse-event counts describe participants recorded with serious and other events, as well as death counts. They do not by themselves determine causation, comparative risk, or the timing and duration of events. The registry lists several serious adverse-event terms at 20.0%, but the information does not provide enough detail to establish attribution or compare the terms across cohorts.
General statistical context: an estimate and its uncertainty are both needed to assess how much information a result provides. A missing result cannot be interpreted as a null result, and an event count cannot substitute for the missing PFS estimate. The most accurate reading is therefore limited: the registry documents the study's design and some safety counts, while the primary efficacy result and important analysis details are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial raises statistical questions that are common in early clinical investigations: how to describe outcomes in a small, heterogeneous set of disease cohorts, how to interpret a time-to-event endpoint with limited follow-up, and how to distinguish descriptive findings from comparative evidence. The single-group design is central. It can generate observations about participants receiving ONC201, but it does not supply a randomized comparator for estimating a treatment contrast.
The primary endpoint was defined in a clinically recognizable way, using time from treatment start to progression or death and a RECIST-based progression rule. The registry also gives an assessment schedule and a follow-up description. Those details provide context for what PFS was intended to represent. Yet the numerical median and its full range are not reported in the registry record, so the intended measure cannot be connected to an observed estimate or judged for precision.
The three cohorts also illustrate why grouping requires care. Hormone receptor-positive breast cancer, triple-negative breast cancer, and endometrial cancer are distinct cohorts in this study. Reporting their safety counts separately preserves that distinction, but comparisons across them are not randomized comparisons and may reflect differences in population and follow-up as well as other factors. The primary endpoint analysis also has a specific population statement: 7/10 participants were analyzed because 3 participants were ineligible.
Finally, the record demonstrates the value of complete statistical reporting. Endpoint estimates, uncertainty intervals, analysis populations, missing-data handling, and prespecified multiplicity methods would help readers assess the strength and limitations of findings. In their absence, interpretation should stay close to what is actually documented: the design, endpoint definition, follow-up description, and adverse-event counts, without converting them into claims of comparative efficacy or treatment causation.
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 primary result is not reported in the registry record. The record identifies median PFS as the primary endpoint and gives the unit and dispersion summary, but provides no median value, full range, or uncertainty interval. The description of average follow-up and the maximum follow-up does not replace an endpoint estimate.
The study used a single-group model without masking and was not a randomized comparison. It therefore lacks a concurrent control for separating outcomes associated with ONC201 from other explanations. The three cohorts involve different disease types and should not be treated as interchangeable comparison groups.
The primary population statement says 7/10 participants were analyzed because 3 participants were ineligible, but the record does not give further details about the eligibility decisions, the analysis population definition, censoring, or missing endpoint data. The registry also does not report the planned statistical methods, interim analyses, or sample-size justification. The planning assumptions described in the record concern an illustration, not the trial's documented design rationale.
Safety information is presented as cohort counts and listed serious-event terms. The record does not provide treatment attribution, event timing, exposure-adjusted rates, or a concurrent control comparison. Death counts are listed without a stated cause. No numerical secondary efficacy results are included in the record details used for this explanation, so response, clinical benefit, and PFS in the other cohorts cannot be assessed from these details.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: ONC201 in Recurrent/Refractory Metastatic Breast Cancer and Advanced Endometrial Carcinoma — NCT03394027.
- Registry record last updated 2022-08-23; status last verified 2022-07.
- Results first posted 2022-01-12.
- 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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18. Record Summary
NCT03394027 is a completed phase 2, single-group study of ONC201 in recurrent or refractory metastatic breast cancer and advanced endometrial cancer. The registry lists enrollment of 30 and describes three cohorts: hormone receptor-positive breast cancer, triple-negative breast cancer, and endometrial cancer. ONC201 was taken orally once every 7 days in 28-day cycles.
The primary endpoint was median PFS in the hormone receptor-positive breast cancer cohort, defined as time from treatment start to progression or death. The record states that 7/10 participants were analyzed because 3 participants were ineligible, but the numerical PFS result is not reported in the registry record. Cohort-specific serious and other adverse-event counts and death counts are listed. Because the study had no concurrent control group, those counts are descriptive rather than comparative.