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 Study of MEDI-573 Plus Standard Endocrine Therapy for Women With Hormone-sensitive Metastatic Breast Cancer (NCT01446159), a randomized phase 2 study. The primary outcome is Phase 1b and Phase 2: Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Treatment Emergent Serious Adverse Events (TESAEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01446159 |
| Phase | Phase 2 |
| Condition | Hormone-sensitive, HER-2 Negative Metastatic Breast Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 188 |
| Arms in the primary outcome | n/a |
| Lead sponsor | MedImmune LLC |
| Results posted | Yes |
2. Clinical Question
Population
Adult women with hormone-sensitive, HER2-negative metastatic breast cancer were the intended study population. The registry describes the disease as HR-positive and HER2-negative metastatic breast cancer. The safety population included participants who received any study therapy.
Intervention
The intervention combined MEDI-573 with an aromatase inhibitor. Phase 1b cohorts received MEDI-573 at 10 mg/kg, 30 mg/kg, or 45 mg/kg, with an aromatase inhibitor chosen by the investigator. Phase 2 Arm 1 used MEDI-573 45 mg/kg plus an aromatase inhibitor. The specified aromatase inhibitor options were letrozole, anastrozole, or exemestane.
Comparator
Phase 2 Arm 2 received an aromatase inhibitor alone, with the investigator choosing among letrozole, anastrozole, or exemestane. The registry describes the overall study as randomized, but does not report the allocation method or the number assigned to each treatment group.
Primary question
The primary outcome counted participants with treatment-emergent adverse events and treatment-emergent serious adverse events. It addresses the occurrence of reported safety events during treatment and the specified follow-up period, rather than tumor response or a comparison of treatment effectiveness.
The study was designed to evaluate safety, tolerability, antitumor activity, and pharmacology of MEDI-573 combined with an aromatase inhibitor. The registry lists tumor-response and time-to-event measures among the secondary outcomes, but outcome estimates for those measures are not reported in the registry record. The posted figures therefore support a description of the reported safety counts, not a conclusion about comparative antitumor activity.
3. Trial Design
This is a randomized, open-label, parallel-group Phase 1b/2 study. The registry lists enrollment of 188 and a status of completed. The recorded study start was 2011-06-13, and primary completion was 2019-06-28. The registry does not report the randomization procedure, allocation ratio, or whether randomization applied across all phases and cohorts.
The study included three Phase 1b cohorts combining MEDI-573 with an aromatase inhibitor. Cohort A received MEDI-573 10 mg/kg, Cohort B received 30 mg/kg, and Cohort C received 45 mg/kg. The 45 mg/kg combination was also used in Phase 2 Arm 1. Phase 2 Arm 2 received an aromatase inhibitor alone. The investigator selected the aromatase inhibitor from letrozole, anastrozole, or exemestane.
The combination regimens specified intravenous MEDI-573 on Day 1 of each 21-day cycle and daily oral aromatase inhibitor. The registry descriptions state that treatment continued until unacceptable toxicity, disease progression, or withdrawal for other reasons, although the available descriptions for some combination arms are truncated. The detailed treatment-stopping rules for every arm are not reported in the registry record.
Masking is listed as none. This means the recorded study was not masked; the registry does not describe any additional procedures for limiting knowledge of assigned treatment. The record lists 23 outcome measures and one analysis. It does not provide a detailed statistical analysis plan, a sample-size justification, or an account of any interim analyses. The posted safety counts are organized by treatment received, consistent with the stated safety-population definition.
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.
Before assignment: A total of 187 participants were screened in the study. Of which, 183 participants were treated with study drugs.
Overall Study
| Stage | MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | MEDI-573 30 mg/kg + AI | MEDI-573 45 mg/kg + AI | Aromatase Inhibitor |
|---|---|---|---|---|
| STARTED | 3 | 3 | 92 | 85 |
| COMPLETED | 0 | 0 | 21 | 23 |
| NOT COMPLETED | 3 | 3 | 71 | 62 |
Reasons for not completing this period:
| Reason | MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | MEDI-573 30 mg/kg + AI | MEDI-573 45 mg/kg + AI | Aromatase Inhibitor |
|---|---|---|---|---|
| Withdrawal by Subject | 1 | 0 | 14 | 11 |
| Lost to Follow-up | 0 | 0 | 1 | 2 |
| Death | 2 | 3 | 43 | 36 |
| Other | 0 | 0 | 13 | 13 |
Analysis population for the primary outcome, as defined in the registry: Safety population included all participants who received any study therapy and were analyzed per the treatment they actually received.
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: Intent-to-Treat (ITT) population included all participants who received any study therapy and were analysed per their randomized treatment group.
| Characteristic | Unit | MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | MEDI-573 30 mg/kg + AI | MEDI-573 45 mg/kg + AI | Aromatase Inhibitor | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 3 | 3 | 92 | 85 | 183 | |
| Age, Continuous | Years | 66.3 (SD 12.3) | 61.0 (SD 8.7) | 63.2 (SD 10.5) | 63.3 (SD 11.0) | 63.2 (SD 10.7) |
| Sex: Female, Male: Female | Participants | 3 | 3 | 92 | 85 | 183 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 7 | 6 | 13 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 | 3 | 85 | 79 | 170 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 1 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 | 0 | 6 | 1 | 8 |
| Race (NIH/OMB): White | Participants | 2 | 3 | 84 | 82 | 171 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 2 | 1 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Phase 1b and Phase 2: Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Treatment Emergent Serious Adverse Events (TESAEs), measured over From the start of study treatment (Day 1) through 60 days after the last dose of treatment or until the participants started another anticancer therapy, whichever occurs first (approximately 8 years).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome counts participants with treatment-emergent adverse events (TEAEs) and treatment-emergent serious adverse events (TESAEs). An adverse event is described as an unfavourable and unintended sign, symptom, or disease temporally associated with study-drug use, whether or not considered related to the drug. A serious adverse event is one that results in death, initial or prolonged inpatient hospitalization, a life-threatening event, persistent or significant disability or incapacity, a congenital anomaly or birth defect, or an important medical event.
Events were considered treatment-emergent if they were absent at baseline and began after treatment, or were present at baseline and worsened in intensity after treatment. The observation window began on Day 1 and continued through 60 days after the last dose or until another anticancer therapy began, whichever occurred first. The registry describes the timeframe as approximately 8 years.
A participant count is a safety summary: it reports how many people in a group experienced at least one event of the specified type. It is not a count of every event, and a participant may have experienced more than one event. The endpoint is useful for describing reported safety experience during the defined observation window. By itself, it does not establish that study treatment caused an event, quantify event duration or severity beyond the serious-event definition, or answer whether treatment altered tumor outcomes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted safety figures show the number of participants with serious adverse events and the number with other treatment-emergent adverse events in each treatment group. In the MEDI-573 10 mg/kg plus aromatase inhibitor group, serious events were reported for 2 of 3 participants, and other events for 3 of 3. In the MEDI-573 30 mg/kg plus aromatase inhibitor group, serious events were reported for 0 of 3 participants, and other events for 3 of 3. In the MEDI-573 45 mg/kg plus aromatase inhibitor group, serious events were reported for 21 of 92 participants, and other events for 86 of 92. In the aromatase-inhibitor group, serious events were reported for 16 of 85 participants, and other events for 79 of 85.
These are descriptive counts from the safety population, which included participants who received any study therapy and were analyzed according to treatment actually received. The Phase 1b groups each contain 3 participants, so their counts describe very small groups. The larger listed groups have more participants, but the registry record does not provide adjusted comparisons, uncertainty intervals, or a statistical test for these safety counts. The figures should not be treated as estimates of a causal treatment effect.
The registry also reports deaths by group: 2, 3, 43, and 36, respectively. These are listed separately from the counts of participants with serious and other adverse events. The record does not give enough information in these figures to determine the cause of each death or whether it was considered treatment-related. A death count should therefore not be interpreted as a count of deaths caused by treatment.
The registry lists several serious-event terms at 33.3%: febrile neutropenia, chest pain, sinus bradycardia, uterine cancer, pleural effusion, and pneumothorax. The record does not clarify the denominator or the event-level context for these percentages in the material, so they should not be used to compare treatment groups or infer the frequency of each event across the full safety population.
The primary endpoint is safety-focused. Although secondary outcomes include best overall tumor response, objective response rate, time to response, duration of response, and time to progression, their results are not reported in the registry record. The available figures therefore do not resolve those efficacy questions.
9. Statistical Methods Explained
The posted primary outcome is a count of participants with treatment-emergent adverse events and serious adverse events. For a count endpoint, the basic descriptive quantity is the number of people meeting the event definition in each group. The registry provides these counts and the corresponding numbers at risk. Such summaries are straightforward to read, but they do not by themselves account for differences in follow-up, baseline risk, or other characteristics between groups.
What does a participant count represent?
A participant with one or more qualifying events contributes to the count of participants affected. The count is not the same as the total number of event episodes: one person may experience several different events, and some events may recur. The reported categories also need to be read according to their definitions. Seriousness is based on specified consequences or clinical importance, while treatment-emergent status depends on timing and change from baseline. Neither label alone establishes that study treatment caused an event.
The observation period matters when interpreting safety counts. The registry defines the window as beginning on Day 1 and ending 60 days after the last dose or when another anticancer therapy starts, whichever occurs first. A count accumulated over a period of observation is not a rate per unit of time. The registry does not report person-time or another adjustment for differences in exposure or duration of follow-up. Consequently, counts alone cannot show whether groups had comparable opportunity to experience and report events.
How should the group counts be compared?
Descriptive comparisons can identify patterns in the posted counts, but a numerical difference between groups is not automatically evidence of a treatment effect. Random allocation can support fair comparisons when implemented as planned, but the registry does not report the allocation method, group-specific baseline characteristics, or an inferential analysis for this safety outcome. The primary analysis described in the record is a count outcome, and the posted information does not include confidence intervals or hypothesis-test results for between-group safety comparisons.
General statistical explanation: a confidence interval expresses the uncertainty around an estimate under the assumptions of the method used. It helps distinguish a relatively precise estimate from one compatible with a wide range of values. No confidence interval for the reported primary safety counts is included in the registry record for this account, so their precision cannot be quantified beyond noting the group sizes.
General statistical explanation: over-dispersion occurs when count variation is greater than a simple model assumes. It can matter in count analyses because an overly restrictive variance assumption may make uncertainty appear smaller than it is. The registry record does not identify a count model, assess over-dispersion, or report a model-based analysis for the primary endpoint. No conclusion about which model was used can be drawn from the posted counts.
What do the planning illustrations mean?
The sample-size assumptions describe planning illustrations based on the observed effect, not the trial's own design. They specify 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. For time-to-event outcomes, the stated convention is a total number of events using the Schoenfeld method; other outcomes use participants per arm. These assumptions are not a record of the trial's actual enrollment rationale or analysis plan. The specific sample-size justification is not reported in the registry record.
General statistical explanation: a planning calculation asks how much information a future study might need under chosen assumptions. It is not a measure of the probability that the completed study detected an effect, and it does not show that a trial was adequately powered. The planning illustrations should therefore be read as conditional scenarios, not as observed power or as evidence that a particular effect was established.
The registry lists one analysis and 23 outcome measures, but it does not give the detailed statistical procedures for the primary outcome. The analysis population is specified for safety: participants who received any study therapy, grouped according to the treatment actually received. The record does not report whether missing observations occurred, how missing safety information was handled, or whether sensitivity analyses were conducted. Those details cannot be inferred from the group counts alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 23 outcome measures, including the primary safety outcome and secondary measures of laboratory results, vital signs, electrocardiograms, tumor response, and time to progression. When a study assesses multiple outcomes, multiplicity can arise because many statistical questions may be examined. General statistical explanation: without an appropriate strategy, repeated testing can increase the chance of at least one apparently notable finding arising by chance. The registry record does not report a multiplicity adjustment, a hierarchy among secondary outcomes, or a prespecified approach for interpreting multiple tests.
The record lists one analysis, but does not describe its statistical methods in detail. It does not report whether interim analyses were planned or conducted, nor does it provide a sample-size justification. These elements are not reported in the registry record and should not be inferred from the completed status or the posted counts.
The safety population included all participants who received any study therapy and were analyzed according to treatment actually received. This is distinct from an analysis based on assigned treatment. The registry does not report a separate intention-to-treat analysis for the primary safety outcome, and the randomization details needed to assess how assigned treatment was handled are not reported.
Missing-data amounts and handling are not reported in the registry record. In general, missing information can affect an analysis when the people or outcomes with missing data differ systematically from those observed. Without a description of missingness, exclusions, or sensitivity analyses, the effect of missing data on these safety summaries cannot be assessed. The posted counts should be interpreted as the recorded participant counts for the listed safety groups, rather than as proof that all planned observations were available.
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 |
|---|---|---|---|
| MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | 2 | 3 | 66.7% |
| MEDI-573 30 mg/kg + AI | 0 | 3 | 0.0% |
| MEDI-573 45 mg/kg + AI | 21 | 92 | 22.8% |
| Aromatase Inhibitor | 16 | 85 | 18.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | 2 of 6 |
| MEDI-573 30 mg/kg + AI | 3 of 6 |
| MEDI-573 45 mg/kg + AI | 43 of 184 |
| Aromatase Inhibitor | 36 of 170 |
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 |
|---|---|
| MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | 3 of 3 |
| MEDI-573 30 mg/kg + AI | 3 of 3 |
| MEDI-573 45 mg/kg + AI | 86 of 92 |
| Aromatase Inhibitor | 79 of 85 |
Most frequent serious adverse event terms
| Event term | Organ system | MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | MEDI-573 30 mg/kg + AI | MEDI-573 45 mg/kg + AI | Aromatase Inhibitor |
|---|---|---|---|---|---|
| Vomiting | Gastrointestinal disorders | 0 of 3 | 0 of 3 | 3 of 92 | 0 of 85 |
| Pleural effusion | Respiratory, thoracic and mediastinal disorders | 1 of 3 | 0 of 3 | 0 of 92 | 2 of 85 |
| Supraventricular tachycardia | Cardiac disorders | 0 of 3 | 0 of 3 | 0 of 92 | 2 of 85 |
| Breast cancer metastatic | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 3 | 0 of 3 | 1 of 92 | 1 of 85 |
| Febrile neutropenia | Blood and lymphatic system disorders | 1 of 3 | 0 of 3 | 0 of 92 | 0 of 85 |
| Atrial flutter | Cardiac disorders | 0 of 3 | 0 of 3 | 0 of 92 | 1 of 85 |
| Abdominal pain upper | Gastrointestinal disorders | 0 of 3 | 0 of 3 | 1 of 92 | 0 of 85 |
| Dysphagia | Gastrointestinal disorders | 0 of 3 | 0 of 3 | 1 of 92 | 0 of 85 |
| Intestinal mass | Gastrointestinal disorders | 0 of 3 | 0 of 3 | 0 of 92 | 1 of 85 |
| Pancreatitis acute | Gastrointestinal disorders | 0 of 3 | 0 of 3 | 1 of 92 | 0 of 85 |
Most frequent non-serious adverse event terms
| Event term | Organ system | MEDI-573 10 mg/kg + Aromatase Inhibitor (AI) | MEDI-573 30 mg/kg + AI | MEDI-573 45 mg/kg + AI | Aromatase Inhibitor |
|---|---|---|---|---|---|
| Fatigue | General disorders | 2 of 3 | 3 of 3 | 41 of 92 | 27 of 85 |
| Nausea | Gastrointestinal disorders | 1 of 3 | 2 of 3 | 34 of 92 | 30 of 85 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 2 of 3 | 1 of 3 | 28 of 92 | 35 of 85 |
| Diarrhoea | Gastrointestinal disorders | 1 of 3 | 0 of 3 | 30 of 92 | 22 of 85 |
| Back pain | Musculoskeletal and connective tissue disorders | 0 of 3 | 1 of 3 | 29 of 92 | 21 of 85 |
| Constipation | Gastrointestinal disorders | 2 of 3 | 1 of 3 | 21 of 92 | 23 of 85 |
| Urinary tract infection | Infections and infestations | 1 of 3 | 1 of 3 | 26 of 92 | 17 of 85 |
| Hot flush | Vascular disorders | 1 of 3 | 1 of 3 | 13 of 92 | 30 of 85 |
| Headache | Nervous system disorders | 0 of 3 | 1 of 3 | 20 of 92 | 19 of 85 |
| Decreased appetite | Metabolism and nutrition disorders | 1 of 3 | 0 of 3 | 19 of 92 | 14 of 85 |
Serious events with the highest arm-level rate: febrile neutropenia (33.3%), chest pain (33.3%), sinus bradycardia (33.3%), uterine cancer (33.3%), pleural effusion (33.3%).
The safety figures report participants with at least one serious adverse event and participants with other treatment-emergent adverse events, alongside the number at risk in each group. They are participant counts, not totals of event episodes. A participant may contribute to more than one event term, and the serious and other-event summaries should not be treated as mutually exclusive unless the registry explicitly says so.
The 10 mg/kg plus aromatase inhibitor group and the 30 mg/kg plus aromatase inhibitor group each list 3 participants at risk. The 45 mg/kg combination group lists 92, and the aromatase-inhibitor group lists 85. Counts from groups of different sizes are not directly comparable as raw totals. The registry does not provide a statistical comparison or uncertainty interval for these figures.
Serious adverse events meet the registry's seriousness criteria; seriousness does not necessarily mean that an event was caused by treatment. The registry's definition also includes important medical events, in addition to outcomes such as hospitalization or a life-threatening event. The listed deaths are a separate set of group counts, and their causes or treatment attribution are not reported in the registry record.
The listed serious-event terms, each reported at 33.3%, lack accompanying denominator and event-level context in the record. They should be read as registry-reported terms, not as group-specific risks or as a complete account of safety.
12. What the Result Does, and Does Not, Mean
The posted results describe treatment-emergent safety events among participants who received study therapy. They show how many participants in each listed group had serious events and other events during the registry-defined observation window. The counts provide a descriptive account of what was recorded, and the small Phase 1b groups make their counts especially limited as summaries of broader experience.
These results do not establish that a reported event was caused by MEDI-573 or an aromatase inhibitor. The event definition is based on timing and change from baseline, and the serious-event definition concerns the nature or consequences of an event. Causal attribution, event severity outside the stated serious criteria, and the clinical circumstances of individual events are not provided in the posted counts.
The counts also do not establish that one treatment approach is safer than another. The registry record does not report inferential comparisons, confidence intervals, or adjustment for factors that could affect observed event counts. The groups differ in size, and the counts do not account for possible differences in exposure time. The data should therefore be understood as descriptive, not as a definitive ranking of the regimens.
Nor do the primary safety results answer the study's tumor-outcome questions. The registry lists response and progression outcomes as secondary measures, but their results are not reported in the registry record. Nothing in the safety counts alone establishes antitumor activity or comparative effectiveness.
The record identifies the study as completed and lists enrollment of 188, while the safety outcome is reported by treatment group. These are different descriptions of the study population; the registry does not provide a reconciliation of the overall enrollment with the group-specific safety denominators in the registry record. Interpretation should remain tied to the participants and event definitions represented in the posted safety figures.
13. Why This Trial Matters Statistically
This trial illustrates why a clinical study's design and its posted outcome need to be considered together. The registry describes a randomized, open-label, parallel-group Phase 1b/2 study with several combination-dose cohorts and a Phase 2 aromatase-inhibitor comparator. The primary outcome is a participant count for treatment-emergent adverse events and serious adverse events, so its main statistical role is to describe safety experience rather than to quantify tumor response.
The group sizes differ substantially in the posted safety results: the two lower-dose Phase 1b groups each include 3 participants, while the 45 mg/kg combination and aromatase-inhibitor groups include 92 and 85, respectively. This makes clear why a raw count cannot be read as a like-for-like comparison across groups. Small cohort counts are also inherently limited in the range of safety patterns they can describe. The registry record does not provide uncertainty estimates that would quantify the precision of these comparisons.
The study also shows the distinction between an outcome being listed and its results being available. Several tumor-response and progression outcomes appear among the secondary measures, but the information reports the primary safety counts rather than those secondary estimates. A long outcome list is not a substitute for results or for a stated plan to control multiplicity.
Finally, the record's planning assumptions should not be mistaken for the trial's own design rationale. The illustrations use specified statistical assumptions, while the actual sample-size justification and detailed analysis plan are not reported in the registry record. Separating descriptive safety results, planning scenarios, and unreported statistical decisions is essential to avoid claims that the posted numbers cannot 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 a detailed statistical analysis plan for the primary safety outcome, including the model or inferential method used. The posted figures lack confidence intervals and formal comparisons between treatment groups. As a result, the precision of the group summaries and the strength of any between-group differences cannot be assessed from these counts alone.
The two smaller combination cohorts each list 3 participants. Their event counts offer limited information about uncommon events or the range of safety experience in a larger population. The registry also does not provide exposure-adjusted rates or person-time, so the counts cannot account for differences in treatment duration or observation time. The observation window ends at the earlier of 60 days after the last dose or initiation of another anticancer therapy, which also limits interpretation to the defined follow-up period.
The record lists deaths by group but does not provide cause, timing, or treatment attribution in the summarized details. It also lists serious-event terms at 33.3% without the context needed to interpret their denominators or distribution across groups. These details limit conclusions about individual serious-event patterns.
Although the registry describes a randomized study, details of sequence generation, allocation concealment, and phase-specific randomization are not reported. The record is open-label, and the safety population is analyzed by treatment actually received. The implications of those features for the reported comparisons cannot be fully evaluated without further methodological detail.
Missing-data amounts and handling, interim analyses, multiplicity procedures, and sample-size justification are not reported in the registry record. Results for the listed secondary tumor outcomes are also not available in the registry record. These limitations restrict interpretation to the posted descriptive safety counts and do not support broader conclusions about efficacy or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of MEDI-573 Plus Standard Endocrine Therapy for Women With Hormone-sensitive Metastatic Breast Cancer — NCT01446159.
- Registry record last updated 2020-06-02; status last verified 2020-05.
- Results first posted 2018-08-28.
- 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
The registry record describes NCT01446159, a completed randomized, open-label, parallel Phase 1b/2 study of MEDI-573 plus an aromatase inhibitor versus an aromatase inhibitor alone in women with hormone-sensitive, HER2-negative metastatic breast cancer. Enrollment is listed as 188. Study start was 2011-06-13, and primary completion was 2019-06-28.
The primary outcome counts participants with treatment-emergent adverse events and serious adverse events. The safety population comprised participants who received any study therapy and were analyzed according to treatment actually received. Posted group counts cover MEDI-573 combination regimens at 10 mg/kg, 30 mg/kg, and 45 mg/kg, and an aromatase-inhibitor group. Secondary outcomes include safety measures and tumor-response and progression measures.
The registry record does not report the detailed analysis plan, sample-size justification, missing-data methods, or results for the listed secondary tumor outcomes. The available safety counts are descriptive and do not, by themselves, establish causation or comparative treatment effects.