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 Study of GDC-0810 Single Agent or in Combination With Palbociclib and/or a Luteinizing Hormone-Releasing Hormone (LHRH) Agonist in Women With Locally Advanced or Metastatic Estrogen Receptor Positive Breast Cancer (NCT01823835), a non-randomized phase 1, phase 2 study. The primary outcome is Phase IIa: Percentage of Participants With Confirmed Objective Tumor Response of GDC-0810 According to RECIST v1.1.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01823835 |
| Phase | Phase 1, Phase 2 |
| Condition | Breast Cancer |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 152 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Genentech, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Women with locally advanced or metastatic estrogen receptor positive breast cancer were eligible for the study. Phase IIa enrolled participants previously treated with an aromatase inhibitor. Its cohorts also distinguished participants by prior fulvestrant treatment, ESR1 mutation status, and treatment history.
Intervention
The study evaluated GDC-0810 as a single agent and in combinations. The registry describes dose escalation and expansion, including GDC-0810 with palbociclib or an LHRH agonist. Phase IIa cohorts received GDC-0810 at the listed dose.
Comparator
There was no randomized control group. The study was nonrandomized, open-label, and conducted in parallel cohorts. Differences between cohorts therefore cannot be interpreted as randomized treatment comparisons.
Primary question
In Phase IIa, what percentage of enrolled participants had a confirmed complete or partial tumor response, assessed by investigators using RECIST v1.1? The registry record does not report the response result.
The study was designed as an early-phase investigation of dose, safety, pharmacokinetics, and proof of concept. Phase Ia used escalating doses of GDC-0810 alone. Phase Ib explored combinations and dose selection, while Phase IIa was intended to characterize activity and other outcomes at the recommended Phase II dose. The clinical question represented by the primary endpoint is descriptive: it concerns the proportion of the Phase IIa population with an investigator-assessed objective response. It is not a comparison with a concurrent untreated or standard-treatment group. Since the response count and the number assessed are not reported in the registry record, the endpoint's observed value and its precision cannot be described.
3. Trial Design
This was an open-label Phase Ia/Ib/IIa study with nonrandomized allocation and parallel cohorts. The registry lists an enrollment of 152 and a terminated status. The study included women with locally advanced or metastatic estrogen receptor positive breast cancer and examined GDC-0810 alone or with palbociclib and/or an LHRH agonist.
Phase Ia was a dose-escalation phase for single-agent GDC-0810. The registry describes sequential assignment to escalating doses using a standard 3 + 3 design, with dose-limiting toxicities assessed from the lead-in through the first treatment cycle. Cohorts varied by dose, dosing frequency, and whether administration was fasting or non-fasting. Phase Ib was a dose-escalation and expansion phase intended to determine a recommended Phase II dose and assess the safety and tolerability of combinations. The listed combination cohorts included GDC-0810 with palbociclib and GDC-0810 with an LHRH agonist.
Phase IIa was a dose-expansion phase. Its cohorts differed according to prior fulvestrant treatment, ESR1 mutation status, and prior aromatase-inhibitor treatment. The primary endpoint was the percentage of Phase IIa participants with a confirmed objective tumor response, based on investigator assessment according to RECIST v1.1. Response assessments were scheduled at screening and repeatedly during treatment, with the registry describing follow-up through disease progression or up to 3 years.
Because allocation was not randomized and there was no control arm, the cohorts do not constitute like-for-like treatment groups. Their purposes and eligibility characteristics also varied. The protocol's detailed allocation procedures beyond the registry description, the rationale for the enrollment target, and any changes made after termination 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.
Only the first 6 of 15 groups are shown.
Overall Study
| Stage | Phase Ia - Cohort 1 | Phase Ia - Cohort 2 | Phase Ia - Cohort 3 | Phase Ia - Cohort 4 | Phase Ia - Cohort 5 | Phase Ia - Cohort 6 |
|---|---|---|---|---|---|---|
| STARTED | 3 | 4 | 4 | 6 | 6 | 6 |
| COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 3 | 4 | 4 | 6 | 6 | 6 |
Reasons for not completing this period:
| Reason | Phase Ia - Cohort 1 | Phase Ia - Cohort 2 | Phase Ia - Cohort 3 | Phase Ia - Cohort 4 | Phase Ia - Cohort 5 | Phase Ia - Cohort 6 |
|---|---|---|---|---|---|---|
| Adverse Event | 0 | 0 | 0 | 0 | 1 | 0 |
| Physician Decision | 0 | 0 | 0 | 0 | 0 | 0 |
| Progressive Disease | 3 | 4 | 3 | 6 | 4 | 6 |
| Study Termination | 0 | 0 | 0 | 0 | 1 | 0 |
| Withdrawal by Subject | 0 | 0 | 1 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All participants that were enrolled in Phase Ia 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.
Only the first 6 of 16 groups are shown.
| Characteristic | Unit | Phase Ia - Cohort 1 | Phase Ia - Cohort 2 | Phase Ia - Cohort 3 | Phase Ia - Cohort 4 | Phase Ia - Cohort 5 | Phase Ia - Cohort 6 |
|---|---|---|---|---|---|---|---|
| Participants analysed | 3 | 4 | 4 | 6 | 6 | 6 | |
| Age, Continuous | Years | 66.3 (SD 5.7) | 63.5 (SD 9.6) | 60.8 (SD 6.9) | 55.3 (SD 8.5) | 69.3 (SD 7.2) | 56.2 (SD 12.8) |
| Sex: Female, Male: Female | Participants | 3 | 4 | 4 | 6 | 6 | 6 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Asian | Participants | 0 | 0 | 0 | 0 | 1 | 1 |
| Race/Ethnicity, Customized: Black or African American | Participants | 0 | 0 | 1 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: White | Participants | 2 | 4 | 3 | 6 | 5 | 4 |
| Race/Ethnicity, Customized: Other | Participants | 1 | 0 | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Unknown | Participants | 0 | 0 | 0 | 0 | 0 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Phase IIa: Percentage of Participants With Confirmed Objective Tumor Response of GDC-0810 According to RECIST v1.1, measured over Screening and every 8 weeks from Cycle 1 Day 1 until Cycle 12, thereafter every 3 months until disease progression (up to 3 years).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint was the percentage of participants enrolled in Phase IIa who had a confirmed objective tumor response to GDC-0810. Objective response was defined as complete response or partial response under RECIST v1.1, as determined by investigator assessment. The registry describes response criteria based on changes in target-lesion size: complete response meant disappearance of all target lesions, and partial response meant at least a 30% decrease in the sum of target-lesion diameters from baseline.
This kind of endpoint reduces a patient's tumor assessment to a binary classification for the specified response definition: a participant either meets the objective-response criteria or does not. The percentage expresses the frequency of that classification in the stated population. It is useful in an early-phase study because it describes observed tumor shrinkage under the study's assessment method. It does not, by itself, establish how outcomes compare with another treatment, how long a response lasts, or whether a change in tumor size improves other outcomes.
The registry specifies assessment at screening and every 8 weeks from Cycle 1 Day 1 until Cycle 12, then every 3 months until progression, up to 3 years. The response count, analysis denominator, and percentage are not reported in the registry record. Consequently, neither the magnitude of the observed response proportion nor its statistical precision can be assessed from the posted primary endpoint information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study's intended primary question but does not provide the primary endpoint result. It gives the endpoint definition and the Phase IIa population, yet no response count, percentage, confidence interval, or statistical test result is reported. Thus, the posted record does not support a numerical description of the observed objective-response proportion or its uncertainty.
The design also limits what any cohort-level percentages could establish. Treatment allocation was nonrandomized, masking was absent, and the study included different phases and cohorts with different doses, combinations, and eligibility characteristics. A contrast between two cohorts would not isolate a treatment effect: differences could reflect participant characteristics, prior therapy, dose, treatment combination, or other factors. The record identifies no randomized comparison.
The listed enrollment of 152 applies to the study overall, not necessarily to the primary endpoint analysis population. The endpoint population is defined as participants enrolled in Phase IIa, and its size is not reported in the registry record. The Phase Ia and Phase Ib cohorts are not part of that endpoint population as described. Without the analysis denominator and information on participants with missing or unevaluable assessments, the completeness of the response assessment cannot be judged.
The registry describes treatment schedules and assessment timing but does not report the primary endpoint analysis method, how confirmation was operationalized, or how missing assessments were handled. It also lists no statistical analyses. These omissions mean that inferential claims, including claims about precision or statistical significance, cannot be reconstructed from the posted record.
The safety figures describe participants affected by serious adverse events and other adverse events in the listed cohorts, along with deaths. They are descriptive counts, not randomized comparisons and not evidence about whether an event was caused by treatment. The record does not provide event-level context, exposure-adjusted rates, or a causal assessment alongside those counts. The data should therefore be read as a registry account of recorded events rather than as a comparative estimate of treatment safety.
Planning illustrations based on an observed effect are not evidence that the study achieved a particular power. They are hypothetical sample-size calculations under stated assumptions. The actual observed effect and the underlying calculation results are not reported in the registry record, and the illustrations do not replace a prespecified design rationale or a completed statistical analysis.
9. Statistical Methods Explained
The primary outcome is a binary response classification summarized as a percentage. In general, a binary endpoint records whether each participant meets a prespecified criterion, rather than the degree or duration of change. For this study, the criterion was confirmed complete or partial response under investigator-assessed RECIST v1.1. A percentage is interpretable only alongside its population and denominator. The registry defines the population as all participants enrolled in Phase IIa, but does not report the number analyzed or the number meeting the response criterion.
What does a confidence interval add?
In general, a confidence interval describes the uncertainty around an estimated quantity under a statistical model and analysis procedure. For a response percentage, it would help readers understand how much precision the observed proportion has, taking account of the number of participants assessed. A point estimate alone cannot convey that precision. The registry record does not report a confidence interval for the primary endpoint, so the precision of the response percentage cannot be evaluated.
Why does the study structure matter?
Randomization is a design method that helps make treatment groups comparable, on average, with respect to both measured and unmeasured characteristics. This study was nonrandomized and had no control arm. Its cohorts were formed around dose escalation, combination treatment, and Phase IIa eligibility characteristics. For that reason, a difference between two cohorts would be an observational contrast, not a randomized estimate of the effect of one treatment versus another. Differences in prior treatment, mutation status, dose, or other participant features could contribute to a contrast.
Open-label means participants and investigators were not masked to treatment assignment. Investigator assessment was part of the primary endpoint definition. In general, unmasked assessment can leave more room for assessment decisions to be influenced by knowledge of treatment, although the registry record does not establish that such influence occurred. RECIST v1.1 provides a defined framework for classifying tumor response, but it does not remove the need to report how assessments were conducted and analyzed.
What does over-dispersion mean?
For a binary percentage, a common statistical model assumes that observations follow the variability expected for the chosen probability model. In general, over-dispersion means the observed variability is greater than that model expects. It can arise when outcomes are more heterogeneous or dependent than assumed. If relevant, ignoring over-dispersion can make uncertainty estimates too narrow. The registry record does not report an over-dispersion assessment or a model for the primary endpoint, so it is not possible to determine whether this issue was considered.
How should the dose-escalation design be understood?
The registry describes a standard 3 + 3 dose-escalation design for Phase Ia. In general, such a design uses small groups of participants and observed dose-limiting toxicities to guide decisions about escalation. It is a dose-finding approach, not a randomized comparison of dose levels. The record states that escalation depended on safety and tolerability and that dose-limiting toxicities were assessed during the lead-in and first cycle. The detailed decision rules and resulting dose-selection analysis are not reported in the registry record.
Phase Ib was intended to identify a recommended Phase II dose for combinations and evaluate concomitant administration. Phase IIa then expanded treatment at the recommended dose to characterize safety, pharmacokinetics, pharmacodynamics, and antitumor activity. These phase-specific aims differ, so the combined enrollment should not be treated as one homogeneous analysis population for the primary endpoint.
What do the planning calculations represent?
In general, a sample-size calculation describes the number of participants that would be needed for a specified statistical objective under stated assumptions. The registry's planning illustration is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such calculations are hypothetical planning quantities, not observed power, and they do not show that the trial was designed or conducted to those targets. The registry record does not report the numerical planning results or a trial-specific sample-size justification. There is also no randomized two-arm comparison described for the primary endpoint, so the illustration should not be read as evidence of a controlled comparison in this study.
Statistical interpretation requires the endpoint result, the population actually assessed, and a defined analysis procedure. The record's endpoint definition and study structure are informative, but the outcome result and analysis details are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The study included multiple phases, dose cohorts, combinations, and secondary outcomes. In general, evaluating several outcomes or subgroup contrasts creates a multiplicity issue: the chance of at least one apparently unusual result can rise as more questions are tested. A prespecified hierarchy, adjustment method, or clear distinction between confirmatory and exploratory analyses can help readers interpret multiple tests. The registry record does not report a multiplicity strategy or a statistical analysis plan. It lists no statistical analyses, so the handling of multiple endpoints or cohort comparisons is not reported in the registry record.
Missing-data handling is also not described for the primary endpoint. The registry defines the Phase IIa population as all participants enrolled in that phase, but does not state how participants without an evaluable response assessment were handled, whether any were excluded from the endpoint calculation, or how missing assessments affected the denominator. These details matter because the observed percentage can depend on which participants are included and how incomplete follow-up is treated.
The record specifies a schedule for tumor assessments but does not report the number of assessments completed, reasons for missing assessments, or a sensitivity analysis. It does not describe an analysis population beyond the endpoint's stated Phase IIa enrollment population. The registry's planned sample-size illustrations are not a substitute for these missing analysis details or for a reported endpoint estimate with its uncertainty.
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 |
|---|---|---|---|
| Phase Ia - Cohort 1 | 1 | 3 | 33.3% |
| Phase Ia - Cohort 2 | 1 | 4 | 25.0% |
| Phase Ia - Cohort 3 | 1 | 4 | 25.0% |
| Phase Ia - Cohort 4 | 1 | 6 | 16.7% |
| Phase Ia - Cohort 5 | 3 | 6 | 50.0% |
| Phase Ia - Cohort 6 | 4 | 6 | 66.7% |
| Phase Ia - Cohort 7 | 1 | 6 | 16.7% |
| Phase Ia - Cohort 8 | 1 | 3 | 33.3% |
| Phase Ia - Cohort 9 | 0 | 3 | 0.0% |
| Phase IIa - Cohort A1 | 4 | 19 | 21.1% |
| Phase IIa - Cohort A2 | 1 | 10 | 10.0% |
| Phase IIa - Cohort B1 | 11 | 53 | 20.8% |
| Phase IIa - Cohort B2 | 1 | 19 | 5.3% |
| Phase Ib - Cohort C1 | 1 | 4 | 25.0% |
| Phase Ib - Cohort D1 | 2 | 6 | 33.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Phase Ia - Cohort 1 | 1 of 3 |
| Phase Ia - Cohort 2 | 1 of 4 |
| Phase Ia - Cohort 3 | 0 of 4 |
| Phase Ia - Cohort 4 | 1 of 6 |
| Phase Ia - Cohort 5 | 2 of 6 |
| Phase Ia - Cohort 6 | 0 of 6 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Phase Ia - Cohort 1 | 3 of 3 |
| Phase Ia - Cohort 2 | 4 of 4 |
| Phase Ia - Cohort 3 | 4 of 4 |
| Phase Ia - Cohort 4 | 6 of 6 |
| Phase Ia - Cohort 5 | 6 of 6 |
| Phase Ia - Cohort 6 | 6 of 6 |
Most frequent serious adverse event terms
| Event term | Organ system | Phase Ia - Cohort 1 | Phase Ia - Cohort 2 | Phase Ia - Cohort 3 | Phase Ia - Cohort 4 | Phase Ia - Cohort 5 | Phase Ia - Cohort 6 |
|---|---|---|---|---|---|---|---|
| FRACTURE | Injury, poisoning and procedural complications | 0 of 3 | 0 of 4 | 1 of 4 | 0 of 6 | 0 of 6 | 1 of 6 |
| CARDIAC FAILURE | Cardiac disorders | 0 of 3 | 0 of 4 | 0 of 4 | 0 of 6 | 1 of 6 | 0 of 6 |
| ABDOMINAL PAIN | Gastrointestinal disorders | 0 of 3 | 1 of 4 | 0 of 4 | 0 of 6 | 0 of 6 | 0 of 6 |
| ASCITES | Gastrointestinal disorders | 0 of 3 | 0 of 4 | 0 of 4 | 1 of 6 | 0 of 6 | 0 of 6 |
| VOMITING | Gastrointestinal disorders | 0 of 3 | 1 of 4 | 0 of 4 | 0 of 6 | 0 of 6 | 0 of 6 |
| PNEUMONIA | Infections and infestations | 0 of 3 | 0 of 4 | 1 of 4 | 0 of 6 | 0 of 6 | 0 of 6 |
| URINARY TRACT INFECTION | Infections and infestations | 1 of 3 | 0 of 4 | 0 of 4 | 0 of 6 | 0 of 6 | 0 of 6 |
| HIP FRACTURE | Injury, poisoning and procedural complications | 0 of 3 | 0 of 4 | 0 of 4 | 0 of 6 | 1 of 6 | 0 of 6 |
| HYPONATRAEMIA | Metabolism and nutrition disorders | 0 of 3 | 0 of 4 | 0 of 4 | 0 of 6 | 1 of 6 | 0 of 6 |
| PULMONARY EMBOLISM | Respiratory, thoracic and mediastinal disorders | 0 of 3 | 0 of 4 | 0 of 4 | 0 of 6 | 0 of 6 | 1 of 6 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Phase Ia - Cohort 1 | Phase Ia - Cohort 2 | Phase Ia - Cohort 3 | Phase Ia - Cohort 4 | Phase Ia - Cohort 5 | Phase Ia - Cohort 6 |
|---|---|---|---|---|---|---|---|
| DIARRHOEA | Gastrointestinal disorders | 1 of 3 | 1 of 4 | 4 of 4 | 4 of 6 | 6 of 6 | 4 of 6 |
| NAUSEA | Gastrointestinal disorders | 1 of 3 | 3 of 4 | 2 of 4 | 6 of 6 | 2 of 6 | 4 of 6 |
| FATIGUE | General disorders | 1 of 3 | 1 of 4 | 3 of 4 | 5 of 6 | 5 of 6 | 2 of 6 |
| ASPARTATE AMINOTRANSFERASE INCREASED | Investigations | 2 of 3 | 1 of 4 | 0 of 4 | 4 of 6 | 3 of 6 | 4 of 6 |
| ANAEMIA | Blood and lymphatic system disorders | 1 of 3 | 2 of 4 | 2 of 4 | 3 of 6 | 4 of 6 | 1 of 6 |
| CONSTIPATION | Gastrointestinal disorders | 2 of 3 | 0 of 4 | 3 of 4 | 4 of 6 | 2 of 6 | 2 of 6 |
| ALANINE AMINOTRANSFERASE INCREASED | Investigations | 2 of 3 | 1 of 4 | 0 of 4 | 3 of 6 | 3 of 6 | 3 of 6 |
| ARTHRALGIA | Musculoskeletal and connective tissue disorders | 1 of 3 | 0 of 4 | 1 of 4 | 2 of 6 | 4 of 6 | 3 of 6 |
| ABDOMINAL PAIN | Gastrointestinal disorders | 2 of 3 | 0 of 4 | 3 of 4 | 2 of 6 | 1 of 6 | 1 of 6 |
| FLATULENCE | Gastrointestinal disorders | 0 of 3 | 0 of 4 | 0 of 4 | 2 of 6 | 2 of 6 | 5 of 6 |
Serious events with the highest arm-level rate: pneumonia (33.3%), urinary tract infection (33.3%), adrenal insufficiency (33.3%), fatigue (33.3%), pneumothorax (33.3%).
The safety record lists serious adverse events, other adverse events, and deaths by cohort. The serious-event figures give the number of participants at risk and the number affected in each listed cohort. These counts describe recorded participants, not the number of individual event episodes. The cohorts differ in size, treatment, and study phase, so their counts should not be compared as though they came from randomized groups with similar follow-up.
The registry also lists serious adverse-event terms and associated percentages, including pneumonia, urinary tract infection, adrenal insufficiency, fatigue, pneumothorax, and atrial fibrillation. The denominator and calculation method for those term percentages are not reported in the registry record. No causal attribution should be inferred from the counts or terms: the record does not establish that an event was caused by study treatment.
Deaths are listed separately by cohort. The registry does not report the causes of death or whether they were considered treatment-related. The figures are therefore descriptive safety information and should not be interpreted as comparative risks or as estimates adjusted for treatment exposure.
12. What the Result Does, and Does Not, Mean
The registry record describes a study intended to assess dose, safety, pharmacokinetics, and early evidence of antitumor activity for GDC-0810 alone and in combinations. It specifies a primary Phase IIa endpoint based on confirmed investigator-assessed complete or partial tumor response under RECIST v1.1. However, it does not report the response result. No conclusion about the observed frequency or precision of response can be drawn from the endpoint information alone.
Even if cohort-level response percentages were available, this design would not provide a randomized estimate of comparative efficacy. Participants were not randomly allocated, and cohorts differed in treatment and eligibility characteristics. A response proportion in a treated cohort is descriptive of that cohort under its assessment conditions. Without a concurrent randomized comparator, it cannot establish how outcomes would differ under another treatment or no study treatment.
The endpoint is also narrower than a complete account of clinical benefit. It records whether specified tumor-size criteria were met; by itself it does not describe response duration, symptoms, quality of life, or survival. Those interpretations require outcomes and analyses that are not reported in the registry record.
Likewise, the safety counts do not establish causation or comparative safety. The record lists events and deaths by cohort but does not provide a causal assessment or adjustment for differences in exposure and follow-up. The study status is terminated, but the reason for termination is not reported in the registry record. The appropriate reading is therefore limited to the study's design, endpoint definition, and posted descriptive safety counts, with the primary outcome and statistical analysis results unavailable.
13. Why This Trial Matters Statistically
This study illustrates why early-phase clinical-trial results need to be interpreted alongside their design. A dose-escalation study can address questions about tolerability and dose selection, while an expansion phase can describe outcomes in a defined group. Those objectives differ from the aim of a randomized comparative trial. Treating all cohorts as interchangeable would obscure the different questions they were built to address.
The distinction between a response definition and a response result is especially important. The registry provides a detailed endpoint definition and assessment schedule, but the response percentage and its uncertainty are not reported. Without those quantities, the endpoint cannot answer its central descriptive question. A clear protocol-level definition is valuable, but it cannot substitute for reporting the number assessed, the number with response, and the precision of the estimate.
The study also shows how nonrandomized allocation affects interpretation. Participants entered cohorts that differed in dose, combination treatment, or clinical characteristics. A numerical contrast across such groups could reflect those differences as well as treatment. This is why early-phase cohort data should not be presented as if they were controlled head-to-head evidence.
Finally, the listed adverse-event counts are useful as descriptive records but require context about attribution, duration of exposure, and completeness of follow-up for comparative interpretation. The registry's limited analysis reporting means readers cannot assess the prespecified handling of missing data, multiplicity, or statistical uncertainty. These issues are central to evaluating what a clinical-trial result can support.
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 registry record does not report the primary objective-response result, its denominator, confidence interval, or statistical test. It also lists no statistical analyses. As a result, the main endpoint cannot be quantitatively interpreted, and the precision of any estimate cannot be assessed from the record.
The study was nonrandomized and open-label, with no control group. Cohorts differed by phase, dose, combination, and eligibility features, including prior treatment and mutation status. These differences limit comparisons between cohorts and leave potential confounding. Investigator assessment was used for the primary endpoint; the registry does not describe independent review or other procedures for limiting assessment bias.
The registry does not report the rationale for the enrollment target, a detailed statistical analysis plan, multiplicity handling, or methods for missing endpoint assessments. The Phase IIa population is defined, but the number with evaluable response assessments and the treatment of incomplete assessments are not stated. Duration of response and other outcome results are not reported in the record described.
Safety information is presented as cohort counts, without the context needed to assess event attribution or compare risks across groups. The term-specific percentages have no reported denominator definition, and causes or treatment relationship for the listed deaths are not given. The reason the study was terminated is also not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of GDC-0810 Single Agent or in Combination With Palbociclib and/or a Luteinizing Hormone-Releasing Hormone (LHRH) Agonist in Women With Locally Advanced or Metastatic Estrogen Receptor Positive Breast Cancer — NCT01823835.
- Registry record last updated 2021-06-18; status last verified 2021-05.
- Results first posted 2021-06-18.
- 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
NCT01823835 was an open-label, nonrandomized Phase Ia/Ib/IIa study of GDC-0810 alone and with palbociclib and/or an LHRH agonist in women with locally advanced or metastatic estrogen receptor positive breast cancer. The registry lists enrollment of 152 and a terminated status.
Phase Ia focused on single-agent dose escalation; Phase Ib evaluated combinations and dose selection; Phase IIa expanded treatment and included the primary objective-response endpoint. That endpoint was the percentage of Phase IIa participants with confirmed investigator-assessed complete or partial response under RECIST v1.1. The registry record does not report the endpoint result or statistical analyses. It lists serious adverse events, other adverse events, and deaths by cohort, but those descriptive figures do not establish treatment causality or comparative risk.