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 Pertuzumab in Combination With Trastuzumab and Chemotherapy in Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Metastatic Gastroesophageal Junction or Gastric Cancer (NCT01774786), a randomized phase 3 study. The primary outcome is Overall Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01774786 |
| Phase | Phase 3 |
| Condition | Gastric Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 780 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Hoffmann-La Roche |
| Results posted | Yes |
2. Clinical Question
Population
Participants with HER2-positive metastatic gastric cancer or gastroesophageal junction cancer. The trial description specifies first-line treatment; the primary analysis population was the intent-to-treat population, consisting of all randomized participants regardless of whether they received study medication.
Intervention
Pertuzumab combined with trastuzumab and chemotherapy. The chemotherapy backbone was cisplatin plus a fluoropyrimidine, either capecitabine or 5-fluorouracil.
Comparator
Placebo combined with trastuzumab and the same described chemotherapy backbone. The placebo-controlled design allows the comparison to focus on adding pertuzumab to the trastuzumab-and-chemotherapy regimen.
Primary question
How did overall survival compare between the pertuzumab and placebo groups? Overall survival was defined as time from randomization to death from any cause. The registry record identifies this endpoint, but the arm-specific survival estimates and sponsor-reported comparison are not reported in the registry record.
The study addressed whether adding pertuzumab to an established combination regimen changed the time participants lived after randomization. Because both groups received trastuzumab and chemotherapy, this was not a comparison of the full combination against no treatment. It was a comparison of two treatment strategies that differed by pertuzumab versus placebo.
The study was randomized and double-blind, which is relevant to how treatment groups were formed and how knowledge of assignment could influence care or outcome assessment. The record describes the trial as multicenter and international. It lists 780 participants as the enrollment figure. The reported safety group sizes were 385 for pertuzumab plus trastuzumab plus chemotherapy and 388 for placebo plus trastuzumab plus chemotherapy.
The clinical question is narrower than whether any one drug is effective in isolation: it concerns the additional contribution of pertuzumab in this specific population and regimen. The registry record describes the setting and endpoint but does not include the numerical primary survival comparison. Therefore, the question can be stated from the design, while the magnitude and precision of the survival result cannot be evaluated from the available result summary.
3. Trial Design
This was a phase III, randomized, double-blind, placebo-controlled, parallel-group study. The registry describes it as multicenter and international. The listed enrollment was 780, and the study status is completed. The record gives a start date of 2013-06-10 and a primary completion date of 2016-12-09.
Participants were assigned to one of two treatment strategies. Both groups received trastuzumab and chemotherapy consisting of cisplatin plus either capecitabine or 5-fluorouracil. One group also received pertuzumab; the comparison group received placebo. The brief study description says the assigned pertuzumab or placebo was given intravenously every 3 weeks, with trastuzumab and chemotherapy. The chemotherapy portion was described for the first 6 treatment cycles. The brief description says participants continued pertuzumab or placebo and trastuzumab until disease progression, unacceptable toxicity, or withdrawal for another reason.
Random assignment is intended to make the groups comparable, on average, with respect to factors that might affect the endpoint. A placebo comparator and double masking can reduce the possibility that expectations about assignment affect treatment or assessment. Those design features do not guarantee that every source of bias is absent, and the registry record does not report details such as the randomization procedure or masking implementation.
The primary endpoint was overall survival in the intent-to-treat population. That population included all randomized participants, whether or not study medication was received. The posted record also lists secondary outcomes including investigator-assessed progression-free survival and objective response under RECIST v1.1, duration of response, clinical benefit, adverse events, left ventricular systolic dysfunction, and quality of life measured with the EORTC QLQ-C30.
The enrollment figure should be read as a trial-level record entry, not as a description of the number included in every outcome analysis. Safety group sizes are reported separately. The registry record does not report a rationale for the planned enrollment or a detailed account of how the primary analysis population translated into the reported outcome analyses.
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 780 participants were enrolled in the study.
Overall Study
| Stage | Pertuzumab + Trastuzumab + Chemotherapy | Placebo + Trastuzumab + Chemotherapy |
|---|---|---|
| STARTED | 388 | 392 |
| Did Not Receive Any Study Treatment | 4 | 3 |
| Received at Least One Dose of Pertuzumab | 384 | 1 |
| Received Placebo (No Pertuzumab) | 0 | 388 |
| COMPLETED | 60 | 46 |
| NOT COMPLETED | 328 | 346 |
Reasons for not completing this period:
| Reason | Pertuzumab + Trastuzumab + Chemotherapy | Placebo + Trastuzumab + Chemotherapy |
|---|---|---|
| Death | 300 | 319 |
| Lost to Follow-up | 6 | 7 |
| Withdrawal by Subject | 18 | 14 |
| Physician Decision | 2 | 0 |
| Non-compliance | 0 | 1 |
| Reason Not Specified | 2 | 5 |
Analysis population for the primary outcome, as defined in the registry: The intent-to-treat (ITT) population included all randomized participants, regardless of whether study medication was 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: The Intent-to-Treat (ITT) population included all randomized participants regardless of whether treatment was actually received, with participants grouped according to the treatment assigned at randomization.
| Characteristic | Unit | Pertuzumab + Trastuzumab + Chemotherapy | Placebo + Trastuzumab + Chemotherapy | Total |
|---|---|---|---|---|
| Participants analysed | 388 | 392 | 780 | |
| Age, Continuous | Years | 60.9 (SD 11.3) | 60.1 (SD 10.7) | 60.5 (SD 11.0) |
| Sex: Female, Male: Female | Participants | 94 | 69 | 163 |
| Sex: Female, Male: Male | Participants | 294 | 323 | 617 |
| Geographic Region: Asia (excluding Japan) | Participants | 143 | 146 | 289 |
| Geographic Region: Japan | Participants | 40 | 40 | 80 |
| Geographic Region: North America/Western Europe/Australia | Participants | 133 | 133 | 266 |
| Geographic Region: South America/Eastern Europe | Participants | 72 | 73 | 145 |
| Prior Gastrectomy: Prior Gastrectomy | Participants | 105 | 102 | 207 |
| Prior Gastrectomy: No Prior Gastrectomy | Participants | 283 | 290 | 573 |
| Human Epidermal Growth Factor Receptor 2 (HER2) Status: IHC 2+/ISH+ | Participants | 129 | 130 | 259 |
| Human Epidermal Growth Factor Receptor 2 (HER2) Status: IHC 3+ | Participants | 259 | 262 | 521 |
| Measurability of Disease, per RECIST v1.1: Measurable Disease | Participants | 351 | 352 | 703 |
| Measurability of Disease, per RECIST v1.1: Non-Measurable Evaluable Disease Only | Participants | 37 | 40 | 77 |
6. Primary Endpoint
The registry lists the primary outcome as Overall Survival, measured over From Baseline until death from any cause (Median [full range] duration of follow-up in Pertuzumab vs. Placebo arms for Primary Analysis: 24.4 [0-42] months vs. 25.0 [0-41] months; Final Analysis: 46.1 [0-70] months vs. 44.4 [0-68] months).
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | Months |
| Endpoint classification | Time-to-Event Analysis |
Overall survival measures the time from randomization until death from any cause. It is a time-to-event endpoint: the outcome is not only whether a death occurred, but also when it occurred relative to randomization. The registry record specifies that participants still alive at the clinical data cutoff were censored at the last date they were known to be alive on or before that cutoff. Participants with no post-baseline data, such as dosing records, imaging dates, or visit dates, were censored at randomization plus 1 day.
In general, overall survival is useful because it has a clear event definition and does not depend on a judgment about whether a tumor has progressed. It can also capture effects of treatment and subsequent events over the period of follow-up. The trade-off is that interpretation depends on the duration and completeness of follow-up, how censoring is handled, and the statistical comparison used.
The endpoint is reported as a median with a 95% confidence interval in months. In general, a median survival time describes the point by which half of the estimated population has experienced the event and half has not. A confidence interval expresses uncertainty around an estimate; it is not a range expected to contain every participant’s survival time.
The timeframe description includes median follow-up durations for the two analysis periods: for the primary analysis, 24.4 [0-42] months in the pertuzumab group and 25.0 [0-41] months in the placebo group; for the final analysis, 46.1 [0-70] months and 44.4 [0-68] months, respectively. These are follow-up descriptions, not the reported median overall-survival estimates. The survival estimates and sponsor-reported between-group comparison are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies overall survival as the primary endpoint and defines it as time from randomization to death from any cause. It also describes censoring for participants known to be alive at the clinical cutoff and for participants without post-baseline data. However, the numerical primary endpoint results needed to assess the treatment-group comparison are not reported in the registry record. In particular, arm-specific median overall survival estimates, their confidence intervals, a hazard ratio, and a p-value are not reported.
The follow-up information is useful context but should not be mistaken for the endpoint result. For the primary analysis, median follow-up was 24.4 [0-42] months in the pertuzumab group and 25.0 [0-41] months in the placebo group. For the final analysis, median follow-up was 46.1 [0-70] months and 44.4 [0-68] months, respectively. Follow-up describes how long participants were observed; it does not state how long they lived. It cannot substitute for the survival curves, medians, or comparative estimate.
The record lists deaths of 299 in the pertuzumab safety group and 318 in the placebo safety group. These figures appear in the adverse-event group summary. Without a corresponding primary analysis table, participant-level follow-up details, and the sponsor’s survival analysis, those counts alone do not establish the relative overall-survival effect. A simple comparison of event counts would not account for when deaths occurred or how long participants were followed.
Safety figures show that serious adverse events affected 178 of 385 participants in the pertuzumab group and 156 of 388 in the placebo group. Other adverse events affected 373 of 385 and 376 of 388 participants, respectively. These are descriptive counts in the posted record. They do not by themselves establish whether an event was caused by a treatment, nor do they account for differences in exposure time or event severity beyond the categories reported.
The registry lists serious-event terms including diarrhoea, decreased appetite, anaemia, pneumonia, vomiting, and dehydration, with percentages shown in the safety summary. The listed terms should be read as reported event information rather than as a complete account of all harms. The record does not present enough detail to compare these specific terms by group or to determine their full clinical context.
Overall, this record supports a clear description of the design, endpoint definition, follow-up periods, and selected safety summaries. It does not support a quantitative conclusion about the primary survival comparison. The absence of the comparative estimate is a limit of the registry record, not evidence that the trial did or did not find a difference.
9. Statistical Methods Explained
The statistical methods can be understood by separating the outcome definition, the treatment comparison, and the handling of participants whose event time was not observed. The registry record supplies the definition of overall survival and censoring rules, but the sponsor’s detailed statistical plan and primary numerical comparison are not reported in the registry record.
Time-to-event outcomes
Overall survival is a time-to-event outcome because each participant contributes information about the time from randomization until death or the last date known alive. If a participant is alive at the analysis cutoff, the exact later time to death is unknown; the participant’s information is therefore censored rather than treated as a death at the cutoff. Censoring preserves the known follow-up without claiming that the event happened on a date when it was not observed.
In general, survival analyses use both event occurrence and time under observation. This is why the numbers of deaths alone do not fully describe the comparison. The timing of events, the amount of follow-up, and censoring all matter. The registry specifies that participants still alive at the cutoff were censored at their last known date alive on or before the cutoff. It also gives a rule for participants without any post-baseline data: censoring at randomization plus 1 day.
Median and confidence interval
The endpoint is described as a median in months with a 95% confidence interval. In general, the median is a summary of the estimated survival distribution, rather than an arithmetic average of individual survival times. The confidence interval communicates uncertainty in the estimated median. A narrow interval generally indicates more precision than a wide interval, although interpretation also depends on the analysis and data structure.
The registry’s follow-up values must be kept distinct from the endpoint medians. The record reports median follow-up and its range for the primary and final analyses, but those values do not give the median time to death. No arm-specific overall-survival median or confidence interval is included in the result information.
Comparing treatment groups
Randomization creates groups intended to be comparable at the start of the study, while the placebo control gives a reference regimen containing trastuzumab and chemotherapy without pertuzumab. In general, a time-to-event comparison may be summarized using a hazard ratio, alongside a confidence interval and a test result. A hazard ratio compares event rates over time under the assumptions of the analysis; it is not a direct ratio of median survival times. The sponsor-reported hazard ratios are not included in the registry record, and no alternate calculation is appropriate from the counts alone.
The record notes that only the sponsor’s reported hazard ratios are used for this time-to-event result. This is important because reconstructing a time-to-event comparison from group-level summary counts would require information not contained in those counts, including event timing and censoring. The posted material does not include a sponsor-reported hazard ratio or the other numerical primary comparison details in this summary.
Analysis population
The primary endpoint population is described as intent-to-treat. This means all randomized participants are included in the population definition regardless of whether study medication was received. In general, an intent-to-treat analysis preserves the comparison created by randomization and estimates the effect of assignment to a strategy. It does not necessarily describe the effect of taking every planned dose, and it does not remove the need to explain missing outcome information or censoring.
The registry separately lists safety group sizes and adverse-event counts. Safety summaries may use treatment exposure or safety populations as defined by the study, but the population rules beyond the figures shown are not reported in the registry record. The primary endpoint’s intent-to-treat definition should therefore not be assumed to describe every secondary or safety analysis.
Planning illustrations
The page includes a sample-size section based on planning illustrations from the observed effect. Such illustrations can show how sample-size requirements would vary under stated assumptions, including the significance level, allocation, approximation, and fraction of effect to detect. They are not the trial’s original design justification and are not observed power. In a time-to-event setting, the planning quantity is the total number of events, rather than participants per arm. The registry record does not report the original sample-size justification or full design assumptions.
A planning calculation is conditional on its assumptions; it does not establish what the trial was designed to detect unless those assumptions match the protocol. It also cannot recover the primary result when the actual comparative estimate is absent. Any displayed sample-size figures should therefore be read as illustrations, not as evidence that the trial had a particular probability of reaching a result or that a result was statistically significant.
Finally, general statistical interpretation should distinguish precision from direction and magnitude. A confidence interval describes uncertainty in an estimate, while a p-value addresses compatibility with a specified null hypothesis under a statistical model. Neither replaces the clinical and design context. Here, the missing primary estimate and uncertainty interval mean that the magnitude, direction, and precision of the overall-survival comparison cannot be assessed from the result summary alone.
10. Multiplicity, Missing Data and Analysis Populations
The record lists multiple secondary outcomes, including progression-free survival, objective response at primary and final analyses, duration of response, clinical benefit, safety outcomes, left ventricular systolic dysfunction, and quality of life. When a study evaluates multiple endpoints or repeated analyses, the chance of a nominally notable result arising by chance can increase. In general, statistical plans may address this through a testing hierarchy or other multiplicity strategy. The multiplicity approach, any testing hierarchy, and any adjustment are not reported in the registry record, so the secondary outcomes should not be treated as if a shared confirmatory testing strategy is documented.
The registry identifies the intent-to-treat population for overall survival and gives censoring rules for the primary endpoint. It does not describe all missing-data procedures for the listed secondary outcomes. For overall survival, censoring is part of the endpoint analysis rather than an assertion that the participant’s later outcome is known. The record says participants alive at cutoff were censored at their last known date alive, and participants without post-baseline data were censored at randomization plus 1 day. The assumptions used to support that handling and any sensitivity analyses are not reported in the registry record.
The posted record names an intent-to-treat population for the primary endpoint, but detailed population definitions for each secondary and safety analysis are not reported. The listed adverse-event group sizes should be read as the safety summaries shown, not automatically as the denominator for every endpoint. Likewise, the enrollment figure does not by itself establish how many participants contributed information to each particular analysis.
Interim analyses, stopping rules, and the full statistical analysis plan are not reported in the registry record. Their absence from this summary should not be interpreted as proof that they were or were not used. Without the prespecified analysis details and complete results, the reader cannot determine how multiplicity, all forms of missingness, and analysis populations were handled across the full set of outcomes.
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 |
|---|---|---|---|
| Pertuzumab + Trastuzumab + Chemotherapy | 178 | 385 | 46.2% |
| Placebo + Trastuzumab + Chemotherapy | 156 | 388 | 40.2% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Pertuzumab + Trastuzumab + Chemotherapy | 299 of 385 |
| Placebo + Trastuzumab + Chemotherapy | 318 of 388 |
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 |
|---|---|
| Pertuzumab + Trastuzumab + Chemotherapy | 373 of 385 |
| Placebo + Trastuzumab + Chemotherapy | 376 of 388 |
Most frequent serious adverse event terms
| Event term | Organ system | Pertuzumab + Trastuzumab + Chemotherapy | Placebo + Trastuzumab + Chemotherapy |
|---|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 17 of 385 | 20 of 388 |
| Pneumonia | Infections and infestations | 14 of 385 | 14 of 388 |
| Decreased appetite | Metabolism and nutrition disorders | 17 of 385 | 9 of 388 |
| Anaemia | Blood and lymphatic system disorders | 8 of 385 | 16 of 388 |
| Vomiting | Gastrointestinal disorders | 7 of 385 | 13 of 388 |
| Dehydration | Metabolism and nutrition disorders | 9 of 385 | 9 of 388 |
| Death | General disorders | 8 of 385 | 9 of 388 |
| Febrile neutropenia | Blood and lymphatic system disorders | 6 of 385 | 9 of 388 |
| Nausea | Gastrointestinal disorders | 7 of 385 | 7 of 388 |
| Acute kidney injury | Renal and urinary disorders | 7 of 385 | 4 of 388 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Pertuzumab + Trastuzumab + Chemotherapy | Placebo + Trastuzumab + Chemotherapy |
|---|---|---|---|
| Nausea | Gastrointestinal disorders | 224 of 385 | 218 of 388 |
| Neutropenia | Blood and lymphatic system disorders | 200 of 385 | 202 of 388 |
| Diarrhoea | Gastrointestinal disorders | 230 of 385 | 125 of 388 |
| Decreased appetite | Metabolism and nutrition disorders | 172 of 385 | 158 of 388 |
| Anaemia | Blood and lymphatic system disorders | 159 of 385 | 142 of 388 |
| Vomiting | Gastrointestinal disorders | 147 of 385 | 122 of 388 |
| Fatigue | General disorders | 144 of 385 | 123 of 388 |
| Palmar-plantar erythrodysaesthesia syndrome | Skin and subcutaneous tissue disorders | 86 of 385 | 100 of 388 |
| Stomatitis | Gastrointestinal disorders | 81 of 385 | 69 of 388 |
| Leukopenia | Blood and lymphatic system disorders | 80 of 385 | 69 of 388 |
Serious events with the highest arm-level rate: diarrhoea (5.2%), decreased appetite (4.4%), anaemia (4.1%), pneumonia (3.6%), vomiting (3.4%).
The safety summary reports serious adverse events for 178 of 385 participants in the pertuzumab plus trastuzumab plus chemotherapy group and 156 of 388 in the placebo plus trastuzumab plus chemotherapy group. It also reports other adverse events for 373 of 385 and 376 of 388 participants, respectively. These are participant counts in the registry summary; they are not measures of how many total events occurred.
The listed leading serious-event terms are diarrhoea (5.2%), decreased appetite (4.4%), anaemia (4.1%), pneumonia (3.6%), vomiting (3.4%), and dehydration (2.3%). The summary does not specify a group assignment alongside each listed percentage, so these terms should not be attributed to one arm based on this record alone. The percentages also do not indicate event duration, recurrence, or severity beyond their identification as serious-event terms.
In general, adverse-event summaries are descriptive. Counts do not establish causation, and comparisons can be influenced by exposure duration, observation, event definitions, and the way events are grouped. The registry reports that safety severity was determined according to NCI CTCAE Version 4.03 among the listed secondary outcomes, but the full safety analysis and detailed event-level context are not included.
The deaths listed in the group summary are 299 and 318, respectively. These figures should not be used alone as a survival comparison: overall-survival analysis depends on event timing and censoring as well as the number of events.
12. What the Result Does, and Does Not, Mean
This trial asks a focused comparative question: whether a regimen including pertuzumab, trastuzumab, and chemotherapy differs in overall survival from a regimen including placebo, trastuzumab, and chemotherapy among participants with HER2-positive metastatic gastric or gastroesophageal junction cancer. Randomization, double masking, and the placebo comparator describe how the trial was designed to make that comparison.
The registry record does not include the numerical primary survival estimates or sponsor-reported comparison. As a result, it is not possible from this record alone to describe the direction or size of the overall-survival result, its precision, or its statistical compatibility with a null effect. The reported follow-up periods are not survival estimates, and the listed deaths are not a substitute for the time-to-event analysis.
The safety summaries do provide descriptive information about participants with serious and other adverse events in each group, together with a list of serious-event terms and percentages. Those figures do not establish that a particular treatment caused an event, and they do not provide a complete account of severity, timing, exposure, or event recurrence. They should be read alongside the full safety reporting rather than as a standalone judgment of comparative risk.
In general, a trial result applies most directly to the population, regimen, outcome definitions, and analysis used in that study. It does not automatically answer questions about other populations, different treatment combinations, or outcomes not evaluated. The record identifies a first-line setting and a specific HER2-positive metastatic population; it does not establish effects beyond those boundaries.
Nothing in the available summary supports a treatment recommendation. It supports explaining the trial question and design, describing selected follow-up and safety information, and identifying what is absent. A complete interpretation of the primary endpoint would require the reported survival estimates, their confidence intervals, the sponsor’s comparative analysis, and relevant details of the analysis plan.
13. Why This Trial Matters Statistically
The statistical importance of this study begins with its comparative structure. Both randomized groups received trastuzumab and chemotherapy, while pertuzumab was compared with placebo. That design targets the incremental contribution of adding pertuzumab to the described regimen, rather than comparing the entire treatment combination with an untreated group.
Overall survival is a time-to-event endpoint, so appropriate interpretation depends on the event times and censoring, not merely on the number of deaths. The record’s definition of the endpoint and its censoring rules help identify what was measured. Its follow-up descriptions also distinguish the primary analysis period from the final analysis period. Those details are important context, but they do not replace the treatment comparison itself.
The record also illustrates why endpoint definitions and analysis populations matter. The primary population is defined as all randomized participants, regardless of whether medication was received. The listed safety summaries have their own group counts. Keeping these populations distinct prevents readers from assuming that every result uses the same denominator or answers the same question.
Equally important is the boundary of interpretation: the primary numerical comparison is not reported in the registry record. Statistical rigor includes recognizing when a result cannot be evaluated, rather than inferring it from follow-up descriptions or event counts. The sample-size illustrations elsewhere on the page are planning exercises based on stated assumptions; they do not recreate the original design rationale or establish observed power.
Finally, the range of listed secondary outcomes raises questions about multiplicity, missing information, and analysis choices. Those methods are not reported in the summary. This makes clear that a transparent endpoint definition is only one part of evaluating a clinical trial; readers also need the estimates, uncertainty, prespecified analysis strategy, and population details to interpret findings fully.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpretation is that the registry record identifies overall survival as the primary endpoint but does not report the arm-specific median survival estimates, confidence intervals, hazard ratio, or p-value. Without those results, the magnitude, direction, and precision of the primary comparison cannot be evaluated. The follow-up summaries and death counts do not fill that gap.
The record describes median follow-up and ranges for the primary and final analyses, but it does not include survival curves or detailed numbers at risk over time in this summary. It does not report how the sponsor addressed the assumptions underlying censoring, or whether sensitivity analyses were performed. The detailed statistical analysis plan is not reported in the registry record.
Although several secondary outcomes are listed, their numerical estimates and analysis details are not included in the registry record. The multiplicity strategy, interim analyses, stopping rules, and the sample-size justification are not reported in the registry record. Therefore, readers cannot assess whether secondary comparisons were confirmatory, how missing data were handled across those outcomes, or how any repeated testing was managed.
The safety summary gives group counts for serious and other adverse events and lists selected serious-event terms with percentages. It does not provide event timing, exposure-adjusted rates, complete event-level detail, or a group attribution for the listed term percentages. Safety counts alone also cannot establish causality.
Finally, the descriptions of the treatment arms are abbreviated in the registry record. The brief summary explains the chemotherapy backbone and continuation treatment, but the arm descriptions are truncated. Detailed protocol procedures, treatment modifications, and other implementation information are not reported in the registry record. These limits concern the available record and do not establish whether further information exists elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Pertuzumab in Combination With Trastuzumab and Chemotherapy in Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Metastatic Gastroesophageal Junction or Gastric Cancer — NCT01774786.
- Registry record last updated 2020-12-30; status last verified 2020-12.
- Results first posted 2018-02-14.
- 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 a completed, randomized, double-blind, placebo-controlled, parallel-group phase III study of pertuzumab added to trastuzumab and chemotherapy for HER2-positive metastatic gastric or gastroesophageal junction cancer. The listed enrollment is 780. The study record gives a start date of 2013-06-10 and a primary completion date of 2016-12-09.
The primary endpoint was overall survival in the intent-to-treat population, defined as time from randomization to death from any cause. The registry also lists multiple secondary efficacy, safety, and quality-of-life outcomes. Follow-up durations are described for primary and final analyses, and selected safety counts and serious-event terms are reported.
The arm-specific primary survival estimates and sponsor-reported comparison are not reported in the registry record. Accordingly, the record supports describing the study design and endpoint, but not a quantitative conclusion about the overall-survival comparison.