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 DS-8201a in Patients With Cancer That Tests Positive for Human Epidermal Growth Factor Receptor 2 (HER2) Protein (NCT03368196), a na phase 1 study. The primary outcome is Treatment-emergent Adverse Events Following Treatment With DS-8201a (Trastuzumab Deruxtecan).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03368196 |
| Phase | Phase 1 |
| Condition | Adenocarcinoma, Gastric, Neoplasm, Breast |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Daiichi Sankyo Taiwan Ltd., a Daiichi Sankyo Company |
| Results posted | Yes |
2. Clinical Question
Population
Chinese patients with HER2-positive advanced and/or refractory gastric, gastroesophageal junction adenocarcinoma, or breast cancer. The registry record reports 12 enrolled participants.
Intervention
DS-8201a, described as trastuzumab deruxtecan, administered by intravenous infusion on Day 1 of each cycle, once every 3 weeks.
Comparator
There was no comparison group. The study was single-group, with no allocation to a control intervention reported.
Primary question
What treatment-emergent adverse events were observed following DS-8201a treatment in this population? The study also assessed pharmacokinetics and listed response-related outcomes.
The primary endpoint concerns the number of participants experiencing treatment-emergent adverse events, rather than a comparison of event rates between treatments. Events were assessed in the Safety Analysis Set. The registry describes the study as assessing safety and tolerability as well as how DS-8201a moves within the body.
Because the study has no comparator group, its central safety question is descriptive: which participants experienced events during the defined assessment period? The record also lists pharmacokinetic measures for DS-8201a and MAAA-1181a after Cycle 1 and Cycle 3, along with investigator-assessed response, objective response rate, and disease control rate. Results for those secondary outcomes are not reported in the registry record. The record therefore does not support a comparative estimate of benefit or harm against another treatment.
3. Trial Design
This was a Phase 1, multicenter, open-label study of DS-8201a. The study is recorded as completed, with a start date of 2018-04-02 and a primary completion date of 2018-09-14. Enrollment was 12. The official title describes participants with HER2-positive advanced and/or refractory gastric, gastroesophageal junction adenocarcinoma, or breast cancer; the brief summary identifies the participants as Chinese patients.
All participants were assigned to the DS-8201a group. The treatment was administered by intravenous infusion on Day 1 of each cycle, once every 3 weeks. The registry record does not report a randomized allocation or a masking procedure; the study is identified as single-group and open-label. There is no control arm, so outcomes cannot be interpreted as a direct comparison with another treatment or with usual care.
The primary outcome was the count of participants with treatment-emergent adverse events. Its timeframe is described as baseline through withdrawal of consent, progressive disease, or unacceptable toxicity, whichever came first, up to approximately 5 months post-dose. The event definition separately specifies that events were considered treatment-emergent if they began after the first dose or worsened in severity or seriousness after treatment began, through 47 days after the last dose.
The registry lists pharmacokinetic outcomes after Cycle 1 and Cycle 3 and response-related secondary outcomes. It does not report the protocol’s rationale for the enrollment target, eligibility details beyond the stated cancer types and HER2 status, or the planned statistical analysis procedures. Those aspects of the design should not be inferred from the study title or the outcomes listed.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: The 6.4 mg/kg DS-8201a dose was chosen for this study based on the efficacy, safety, and pharmacokinetic profiles established in an earlier Phase 1 trial.
Overall Study
| Stage | DS-8201a |
|---|---|
| STARTED | 12 |
| COMPLETED | 12 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Treatment-emergent adverse events (TEAEs) were assessed in the Safety Analysis Set.
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: Baseline demographics were assessed in the Safety Analysis Set.
| Characteristic | Unit | DS-8201a |
|---|---|---|
| Participants analysed | 12 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 |
| Age, Categorical: >=65 years | Participants | 1 |
| Age, Continuous | years | 54.8 (SD 8.73) |
| Sex: Female, Male: Female | Participants | 12 |
| Sex: Female, Male: Male | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 12 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 0 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: Taiwan | participants | 12 |
6. Primary Endpoint
The registry lists the primary outcome as Treatment-emergent Adverse Events Following Treatment With DS-8201a (Trastuzumab Deruxtecan), measured over Baseline up to withdrawal of consent, progressive disease, or unacceptable toxicity (whichever came first), up to approximately 5 months post-dose.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who experienced treatment-emergent adverse events (TEAEs) after receiving DS-8201a. The registry defines a TEAE as an adverse event that was absent before the first dose and occurred after treatment began, or an event that worsened in severity or seriousness after treatment began. The definition extends through 47 days after the last dose. Events were to be coded using MedDRA Version 20.1 and graded for severity using CTCAE Version 4.03.
A participant count is a descriptive safety measure: it indicates how many people in the assessed group experienced an event, rather than how many episodes occurred. A participant may experience more than one event, so participant counts should not be read as total event counts. The endpoint is assessed in the Safety Analysis Set. The registry record does not specify further membership criteria for that set.
General: In an early-phase study, describing observed adverse events and their severity is a way to characterize safety and tolerability in the studied group. Such a count does not by itself establish whether an event was caused by treatment. Nor can a single-group count determine how event frequency compares with another treatment or with the frequency that would have occurred without treatment.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary safety results describe participants in a single DS-8201a group. Of 12 participants at risk for serious adverse events, 2 were reported as having a serious adverse event. The registry lists Febrile neutropenia and Urinary tract infection among the serious terms, each at 8.3%. It also reports that all 12 participants were at risk for other adverse events and that 12 were affected. The reported death count is 0.
These are participant counts, not a count of every event episode. The serious-event figure indicates how many participants had at least one serious adverse event in the registry’s reporting, not the total number of serious events. A participant could have more than one event or term, and the registry record does not provide enough detail to reconstruct event-level overlap. The listed percentages are presented as recorded and should not be treated as estimates from a controlled comparison.
The study enrolled 12 participants and had no comparator arm. Consequently, its safety data describe the experience of this group but cannot isolate the effect of DS-8201a from other influences or establish how these outcomes compare with another treatment. The small group also means that the observed counts describe only a limited set of participants. No confidence intervals or inferential analyses are reported in the registry record, so the precision of the event-frequency estimates cannot be quantified from the reported results.
The registry lists pharmacokinetic outcomes and response-related secondary outcomes, but their results are not reported in the registry record. The presence of those outcomes in the record is not evidence of a particular pharmacokinetic profile or response. No conclusion about comparative efficacy can be drawn from the reported primary safety counts.
General: A confidence interval expresses the range of values compatible with data under a specified statistical model. Its width reflects uncertainty as well as the amount of information in the data. Without a reported interval or a detailed analysis, readers should not infer precision from the point counts alone. Similarly, a zero reported death count is an observation in this study group; it does not establish that the risk of death is absent.
9. Statistical Methods Explained
What does the primary count represent?
The endpoint is a count of participants with treatment-emergent adverse events, and the unit is participants. It is therefore a binary participant-level outcome for each person: the person either experienced at least one event meeting the definition during the assessment period or did not. The reported count does not enumerate every event episode, and it does not distinguish event severity unless the results separately report severity or seriousness.
The registry defines treatment-emergent events by timing and change from baseline: an event was absent before the first dose and occurred afterward, or it worsened in severity or seriousness after treatment began. The defined window extends to 47 days after the last dose. The outcome timeframe is also described as running from baseline until withdrawal of consent, progressive disease, or unacceptable toxicity, whichever came first, up to approximately 5 months post-dose. These descriptions identify the intended observation period; participant-specific follow-up durations are not reported in the registry record.
Why is a participant count useful?
General: A count makes the number of affected participants explicit and is straightforward to interpret in a safety description. It answers how many people in the assessed group experienced an event, not how frequently events occurred per unit of follow-up. If observation time differs between participants, a simple count does not account for that difference. The registry record does not report a person-time rate for the primary outcome.
For a binary outcome, statistical summaries may include the observed proportion and an uncertainty interval. General: An interval conveys how much uncertainty remains around an estimate, given the observed data and the method used. The registry results report participant counts, but no confidence interval or inferential analysis is reported. No additional estimate should be inferred from the counts.
What can a single-group design establish?
This study has one treatment group and no control group. General: A single-group study can describe what was observed among participants receiving the intervention, but it cannot directly estimate a difference between that intervention and a comparator. Without a comparison group, the observed events cannot be separated statistically from background events, changes in participants’ conditions, or other influences. The design is open-label, and no masking procedure is reported.
For the same reason, the posted results do not provide a treatment contrast, a relative effect, or a comparative confidence interval. The absence of a comparator is a design feature, not a statistical finding. The registry record also does not report an adjustment model or a covariate-adjusted safety analysis.
How should the listed safety categories be read?
The serious adverse event results report participants at risk and participants affected. These are participant denominators and numerators, not event totals. The registry separately gives the most frequent serious terms as Febrile neutropenia and Urinary tract infection, each at 8.3%. Those entries describe the listed terms and should not be interpreted as an exhaustive accounting of all event types unless the registry says so; an exhaustive event-level listing is not reported in the record.
The event coding and grading standards are MedDRA Version 20.1 and CTCAE Version 4.03. General: Standardized coding supports consistent categorization of reported events, while severity grading classifies the intensity of events according to the stated criteria. Neither coding nor grading by itself establishes that treatment caused an event.
What statistical details are not reported?
The registry record does not report a trial-specific statistical analysis plan, a sample-size justification, interim analyses, missing-data procedures, or methods for handling multiple outcomes. It does not report inferential tests for the primary outcome. General: These details matter because the analysis plan determines how outcomes are summarized, how uncertainty is quantified, and how several outcomes are interpreted together. Their absence means readers should not assume a particular test, adjustment, or missing-data strategy was used.
The record identifies the Safety Analysis Set for the primary outcome, but does not give further criteria defining that population. It does not report a separate intention-to-treat analysis population. Any more detailed description of population membership or analysis methods is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists multiple secondary outcomes alongside the primary safety endpoint. These include pharmacokinetic measures for DS-8201a and MAAA-1181a after Cycle 1 and Cycle 3, plus best overall response, objective response rate, and disease control rate. The record lists 8 outcome measures in total, but does not report results for the secondary outcomes in the registry record.
Multiplicity arises when several outcomes or statistical tests are considered. General: With multiple tests, the chance of at least one apparently notable result can increase if each test is interpreted separately without an adjustment. A prespecified hierarchy or adjustment can address this issue, but the registry record does not report whether a multiplicity procedure or outcome hierarchy was planned. No multiplicity-adjusted results are reported.
The primary endpoint population is identified as the Safety Analysis Set. Further eligibility criteria for that analysis set are not reported in the registry record. The record does not describe how missing observations were handled, whether any participants had incomplete follow-up, or how missing outcome data were treated. It also does not report whether the analysis included all enrolled participants or only those with available assessments. Consequently, the completeness of follow-up and the effect of missingness on the reported counts cannot be assessed from the registry record.
General: Missingness can affect interpretation when participants with unavailable outcomes differ from those with observed outcomes. Different assumptions about missing observations can lead to different estimates, so transparent reporting of the analysis population and missing-data approach is important. No assumptions should be attributed to this study without a reported method.
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 |
|---|---|---|---|
| DS-8201a | 2 | 12 | 16.7% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| DS-8201a | 0 of 12 |
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 |
|---|---|
| DS-8201a | 12 of 12 |
Most frequent serious adverse event terms
| Event term | Organ system | DS-8201a |
|---|---|---|
| Febrile neutropenia | Blood and lymphatic system disorders | 1 of 12 |
| Urinary tract infection | Infections and infestations | 1 of 12 |
Most frequent non-serious adverse event terms
| Event term | Organ system | DS-8201a |
|---|---|---|
| Nausea | Gastrointestinal disorders | 7 of 12 |
| Platelet count decreased | Investigations | 7 of 12 |
| Aspartate aminotransferase increased | Investigations | 6 of 12 |
| White blood cell count decreased | Investigations | 5 of 12 |
| Anaemia | Blood and lymphatic system disorders | 4 of 12 |
| Alanine aminotransferase increased | Investigations | 4 of 12 |
| Decreased appetite | Metabolism and nutrition disorders | 4 of 12 |
| Stomatitis | Gastrointestinal disorders | 3 of 12 |
| Fatigue | General disorders | 3 of 12 |
| Blood bilirubin increased | Investigations | 3 of 12 |
Serious events with the highest arm-level rate: febrile neutropenia (8.3%), urinary tract infection (8.3%).
The registry reports 2 participants with serious adverse events among 12 at risk. Febrile neutropenia and Urinary tract infection are each listed at 8.3% among the serious terms. These figures refer to participants and listed terms; they are not a complete count of event episodes. The record also reports 12 participants affected by other adverse events among 12 at risk, and 0 deaths.
The primary endpoint uses the term treatment-emergent, which describes when an event began or worsened relative to treatment. It does not, by itself, establish that DS-8201a caused the event. Seriousness and severity are also distinct concepts: the registry describes seriousness and grades severity using CTCAE Version 4.03, but the reported serious-event counts should not be treated as a severity distribution.
Because this is a single-group study with 12 enrolled participants, the results describe this group and do not provide a comparison with an untreated group or another intervention. The registry record does not report confidence intervals for these safety results, so their statistical precision is not quantified there. The reported counts should be read as descriptive observations, not as proof that an event will or will not occur in other patients.
12. What the Result Does, and Does Not, Mean
The registry results provide a descriptive account of adverse events among participants treated with DS-8201a in this Phase 1 study. The primary outcome is safety-focused, and the posted counts show participants affected by serious and other adverse events during the defined observation period. The record reports 2 participants with a serious adverse event, 12 with other adverse events, and 0 deaths. It lists Febrile neutropenia and Urinary tract infection at 8.3% each among serious terms.
These results do not establish that DS-8201a caused any particular event. The treatment-emergent definition establishes timing or worsening relative to treatment, whereas causality requires a separate assessment. The registry record does not report a causal analysis or a comparison group that could help distinguish treatment-associated events from events that might occur for other reasons.
The study also does not provide a comparative estimate of effectiveness. Response-related outcomes are listed, but their results are not reported in the registry record. The pharmacokinetic outcomes are also listed without results. Therefore, the listed outcomes alone cannot support a conclusion about response, disease control, or drug exposure.
General: Results from a small single-group study can be informative as observations in the enrolled participants, but they are not a substitute for a controlled comparison. The absence of a reported event in a group does not show that the event is impossible, and an event observed during treatment does not show that treatment caused it. The registry record gives no confidence intervals or inferential analyses to quantify uncertainty around its reported counts.
The study’s findings should be understood within its defined population: Chinese patients with HER2-positive advanced and/or refractory gastric, gastroesophageal junction adenocarcinoma, or breast cancer. The record does not establish that the observed results apply to populations outside those described. It also does not report enough detail to assess the effects of incomplete follow-up or missing outcome data.
13. Why This Trial Matters Statistically
This trial is statistically notable for the kind of question its design can answer. As a Phase 1, open-label, single-group study, it reports safety observations after treatment rather than a comparison between randomized groups. That makes the participant counts useful as descriptive information, while placing clear limits on causal and comparative interpretation.
The primary endpoint is a participant count for treatment-emergent adverse events. That distinction matters: a count of affected people is not the same as a count of event episodes, and it does not account for differences in observation time. The registry gives a defined event window and identifies the Safety Analysis Set, but does not report participant-specific follow-up, a person-time analysis, or further details of the analysis population.
The study also lists pharmacokinetic and response-related outcomes, reflecting several distinct measurement questions. The registry record does not report those outcome results or a plan for handling multiple outcomes. Without results and analysis details, readers cannot evaluate the precision of those measures or how they were interpreted alongside the primary endpoint.
General: Statistical interpretation depends on matching conclusions to design and data. A single-group event count describes what occurred among enrolled participants; it does not estimate what would have occurred under a different intervention. Reporting uncertainty, analysis populations, and missing-data methods would help readers judge how stable and complete the estimates are. Those details are not reported in the registry record.
The record’s value is therefore in its documented study design, event definitions, and observed safety counts. Keeping the descriptive nature of the evidence in view prevents participant counts from being mistaken for treatment comparisons or causal effects.
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 most important design limitation is the absence of a comparator group. This is a single-group study, so the reported safety counts cannot be contrasted directly with outcomes under another intervention. The open-label design also means no masking procedure is reported. The registry record does not provide details that would allow the possible influence of open-label assessment to be evaluated.
Enrollment was 12, limiting the amount of information in the reported participant counts. The registry does not report confidence intervals or inferential analyses for the primary endpoint. It is therefore not possible to quantify the precision of the event-frequency estimates from the registry results alone. The study’s rationale for its enrollment target and any trial-specific sample-size justification are not reported in the registry record.
The population includes several cancer categories: gastric, gastroesophageal junction adenocarcinoma, and breast cancer, all described as HER2-positive and advanced and/or refractory. The registry record does not provide outcome results separately by cancer type, so it does not allow assessment of whether the reported observations differed across these groups.
The record identifies the Safety Analysis Set but does not provide its detailed membership criteria. It also does not report participant-level follow-up, missing-data procedures, or whether any outcomes were unavailable. The listed pharmacokinetic and response-related outcomes do not have reported results in the registry record. The statistical analysis plan, interim analyses, and methods for addressing multiple outcomes are also not reported. These gaps limit assessment of completeness, precision, and the interpretation of outcomes beyond the posted safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: DS-8201a in Patients With Cancer That Tests Positive for Human Epidermal Growth Factor Receptor 2 (HER2) Protein — NCT03368196.
- Registry record last updated 2022-11-03; status last verified 2022-11.
- Results first posted 2021-06-14.
- 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
NCT03368196 is a completed Phase 1, multicenter, open-label, single-group study of DS-8201a in Chinese patients with HER2-positive advanced and/or refractory gastric, gastroesophageal junction adenocarcinoma, or breast cancer. The registry reports 12 enrolled participants. DS-8201a was administered by intravenous infusion on Day 1 of each cycle, once every 3 weeks.
The primary outcome was the count of participants with treatment-emergent adverse events in the Safety Analysis Set. The registry reports 2 participants with serious adverse events, 12 with other adverse events, and 0 deaths. Febrile neutropenia and Urinary tract infection are each listed at 8.3% among serious terms. The study has no comparator group, and no inferential analyses or results for the listed secondary outcomes are reported in the registry record.