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 Avatrombopag for the Treatment of Thrombocytopenia in Adults Scheduled for a Surgical Procedure (NCT03326843), a na phase 3 study. The primary outcome is Evaluate Efficacy of Avatrombopag in Increasing Platelet Counts in Subjects With Thrombocytopenia Scheduled for Operations.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03326843 |
| Phase | Phase 3 |
| Condition | Thrombocytopenia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sobi, Inc. |
| Results posted | Yes |
2. Clinical Question
The study asked whether avatrombopag could increase platelet counts in adults with thrombocytopenia who were scheduled for operations at critical sites or operations with a high risk of bleeding. Its primary outcome focused on reaching a specified platelet-count threshold on the day of the procedure, rather than on comparing outcomes between treatments.
Population
Adults with thrombocytopenia scheduled for a surgical procedure. The study description emphasizes operations at critical sites or operations with a high risk of bleeding. The registry record reports four participants enrolled.
Intervention
Open-label oral avatrombopag 60 mg. The registry record describes one treatment group and does not report a dosing schedule or additional treatment details.
Comparator
There was no comparator group. The study was recorded as single-group, with allocation listed as not applicable. It therefore does not provide a like-for-like treatment comparison.
Primary question
What proportion of participants achieved a platelet count >100 x 10^9 platelets/L on procedure day, from baseline to 10-13 days? The registry record gives the endpoint definition but does not report the observed proportion.
This distinction shapes what can be learned from the record. A single-group study can describe outcomes among participants who received the intervention, but without a concurrent comparator it cannot separate changes associated with treatment from other explanations. The absence of a posted primary-outcome analysis also means the endpoint cannot be quantitatively assessed from the registry record.
3. Trial Design
This was a phase 3, open-label, multicenter study of avatrombopag for thrombocytopenia in adults scheduled for surgery. The intervention was oral avatrombopag 60 mg, and the registry describes a single treatment group. Masking was listed as none and allocation as not applicable. With no comparator group, the design was not a randomized treatment comparison.
The registry record lists an enrollment of four participants. The study began on 2018-03-26, and the primary completion date is 2019-02-25. Its status is terminated. The reason for termination and any termination date are not reported in the registry record. The sponsor is Sobi, Inc.
The primary outcome was the proportion of participants who achieved a platelet count >100 x 10^9 platelets/L on procedure day, with a timeframe from baseline to 10-13 days. The listed secondary outcome concerns the incidence of treatment-emergent adverse events. The record lists two outcome measures, but a second measure beyond the identified primary and safety outcomes is not described in the information available in the registry record.
Four enrolled participants and the recorded termination status are important context for interpreting the study. The record does not report how many participants completed treatment, underwent a procedure, or contributed data to each outcome. Those details should not be inferred from enrollment alone. The protocol’s planned enrollment, design rationale, and reasons for ending the study are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Avatrombopag 60 mg |
|---|---|
| STARTED | 4 |
| COMPLETED | 4 |
| NOT COMPLETED | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Avatrombopag 60 mg |
|---|---|---|
| Participants analysed | 4 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 |
| Age, Categorical: >=65 years | Participants | 3 |
| Age, Continuous | years | 66 (51 to 77) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 2 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 3 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 4 |
| Platelet Counts | 10^9 platelets/L | 68 (64 to 73) |
6. Primary Endpoint
The registry lists the primary outcome as Evaluate Efficacy of Avatrombopag in Increasing Platelet Counts in Subjects With Thrombocytopenia Scheduled for Operations, measured over Baseline to 10-13 days.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | proportion of total participants |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the proportion of participants who achieved a platelet count >100 x 10^9 platelets/L on the day of the procedure. The stated observation period runs from baseline to 10-13 days. This is a threshold-based, binary outcome: each participant either meets the stated platelet-count criterion on procedure day or does not.
A threshold outcome can make a clinical measurement easier to interpret by focusing on whether participants reach a prespecified level, rather than describing only the average count. In general, such endpoints can be useful when the level itself is the central question. However, the registry record does not report why this particular threshold was selected, whether it was prespecified in a protocol, or how the timing was handled for participants whose procedure dates differed.
The endpoint is a proportion, but its observed value is not reported in the registry record. The record also does not provide participant-level counts, a confidence interval, or an analysis population for this endpoint. Accordingly, the endpoint definition describes what was intended to be measured; it does not establish how many participants achieved the threshold or how precisely that proportion was estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a focused primary question but does not include a primary-outcome result or an outcome analysis. It reports four enrolled participants and gives the platelet threshold and observation period, yet it does not state how many participants reached the threshold on procedure day. No estimate of the proportion, confidence interval, or inferential test is reported in the registry record. The primary question therefore cannot be answered quantitatively from the posted results.
The design also limits the scope of possible interpretation. This was a single-group, open-label study with no comparator. Any outcome observed among participants receiving avatrombopag would describe that group; it would not by itself establish what would have happened to comparable participants under another treatment or without the intervention. A randomized comparison can help distinguish treatment effects from differences in participant characteristics and other influences, but this study was not designed as such a comparison.
The reported safety counts describe the group but do not resolve the efficacy question. In the avatrombopag 60 mg group, four participants were at risk for serious adverse events and zero were reported as having a serious adverse event. Four were at risk for other adverse events and four were reported as having other adverse events. Zero deaths were reported. These counts are descriptive; they do not provide a controlled comparison, and the record does not give event details or a time-specific account of adverse events.
Precision is also a central issue. In general, estimates based on small numbers of participants can be highly uncertain, and a confidence interval would help show the range of values compatible with the observed data. No confidence interval for the primary outcome is reported in the registry record. The enrollment count alone does not supply that missing estimate, and no recalculated outcome analysis is available from the posted information.
The record states that the study was terminated, but does not report why it ended or whether termination affected outcome collection. It also does not report missing-data handling, the number analyzed for each outcome, or whether all enrolled participants had a procedure. These omissions prevent assessment of how representative the analyzed participants might be of everyone enrolled. Overall, the record documents the study question, design, enrollment, and some adverse-event counts, but not the primary result needed to describe the measured platelet response.
9. Statistical Methods Explained
The available information supports a limited statistical reading. The primary endpoint is a proportion, the design has one treatment group, and the registry record reports no outcome analyses. General statistical concepts can clarify what the endpoint would mean and what information is needed to interpret it, but they cannot substitute for a missing estimate.
What does a proportion measure?
For a binary endpoint, a proportion represents the share of participants meeting a defined condition. In this study, the condition is achieving a platelet count >100 x 10^9 platelets/L on procedure day. Interpreting a proportion requires knowing both the number who met the condition and the number included in the analysis. The registry record does not report either count for the primary endpoint, so an observed proportion cannot be stated.
A confidence interval is a statistical range that conveys uncertainty around an estimate. In general, a narrower interval indicates greater precision, while a wider interval indicates less precision. The interval would not remove limitations from the study design, but it would show how much uncertainty surrounds the estimated proportion. No primary-outcome confidence interval is reported in the registry record.
What can a single-group design establish?
A single-group design can describe outcomes among participants who received the intervention. Without a comparator, it cannot directly estimate a difference between treatment strategies. Changes over time may reflect the intervention, natural variation, the circumstances of the procedure, or other factors. In general, random allocation to concurrent groups helps balance known and unknown factors, while an uncontrolled group cannot provide that same protection against alternative explanations. Here, allocation is listed as not applicable and the study model is single group.
Open-label status means masking was not used, as recorded in the registry. In general, knowledge of treatment assignment can influence decisions about care, measurement, or reporting, depending on the outcome and study procedures. A laboratory platelet count is a measurement, but the registry record does not describe laboratory procedures or safeguards. Those details should not be assumed.
How should the planning assumptions be read?
The planning illustration is described as a hypothetical calculation based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It is explicitly a planning illustration rather than the trial’s own design. The stated framework refers to detecting a fraction of the observed effect; it does not turn this single-group study into a two-arm comparison.
Such sample-size planning figures, when available, describe how many participants might be needed under specified assumptions. They are not evidence that a study had a particular probability of detecting an effect, and they are never observed power. Their interpretation depends on the effect size and other assumptions used. The primary outcome estimate needed to anchor the described illustration is not reported in the registry record, and no numerical planning results are stated in the registry record. Therefore, no planning figure can be evaluated as a measure of this study’s achieved precision.
Why does the analysis population matter?
The enrolled group and the group analyzed for an endpoint may differ if participants do not complete the study, do not undergo the procedure, or lack a measurement. In general, an analysis population defines whose data contribute to a reported result. The registry record gives an enrollment of four but does not report the number analyzed for the primary endpoint, the number with a procedure-day measurement, or the rules used to include participants. It is therefore not possible to determine whether the endpoint denominator was all enrolled participants or a subset.
Missing outcomes can affect a proportion if participants without measurements are excluded or classified in a particular way. Statistical methods for missing data rely on assumptions about why values are missing and how the missing observations relate to observed information. No missing-data approach is reported in the registry record. Without the number and handling of missing primary measurements, the potential effect of missingness cannot be assessed.
What can the adverse-event counts say?
Counts describe how many participants were recorded with an event in the study group. They do not, on their own, establish comparative risk. In general, interpreting safety also involves event definitions, observation time, severity, and the completeness of reporting. The registry record gives group-level counts for serious adverse events, other adverse events, and deaths, but does not provide event terms or timing. With no comparator and no detailed event descriptions, the counts should be read as a limited descriptive record rather than a comparative safety analysis.
Finally, the registry lists two outcome measures and reports zero analyses. An endpoint’s presence in the record is not equivalent to a reported result. A complete statistical interpretation would need the outcome values, analysis population, uncertainty estimates, and relevant analysis methods. Those items are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies a primary outcome and a secondary safety outcome, and it lists two outcome measures. The information available does not describe a multiplicity plan, such as how inference across multiple outcomes or tests would be controlled. In general, examining multiple outcomes can increase the chance of finding an apparently notable result by chance; prespecifying which outcomes are primary and how they will be interpreted helps readers understand that risk. A detailed plan is not reported in the registry record.
The record does not report whether there were interim analyses, and it does not describe adjustments for interim looks. It also does not report a statistical analysis plan or analysis methods for the outcomes. No assumptions about these procedures can be made from the study’s phase or design.
Missing-data rules and analysis populations are likewise not reported in the registry record. The enrollment count is four, but the number included in the primary-outcome analysis is not stated. The record does not say how participants without a procedure-day platelet measurement would be handled, whether all enrolled participants were expected to contribute to each outcome, or whether analyses used a particular population definition. These details matter because the denominator and handling of unavailable measurements affect the interpretation of a proportion.
In general, a transparent account of missing observations should state how many values were unavailable, why they were missing when known, and what method was used to address them. The registry record does not provide this information. Consequently, the possible influence of missing data, multiplicity, or analysis-population choices on the unreported primary result cannot be assessed.
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 |
|---|---|---|---|
| Avatrombopag 60 mg | 0 | 4 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Avatrombopag 60 mg | 0 of 4 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Avatrombopag 60 mg | 4 of 4 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Avatrombopag 60 mg |
|---|---|---|
| Influenza | Infections and infestations | 1 of 4 |
| Urinary Tract Infection | Infections and infestations | 1 of 4 |
| Urinary Retention | Renal and urinary disorders | 1 of 4 |
| Gout | Metabolism and nutrition disorders | 1 of 4 |
| Subcutaneous hematoma | Injury, poisoning and procedural complications | 1 of 4 |
For avatrombopag 60 mg, the registry record lists four participants at risk for serious adverse events and zero participants with a serious adverse event. It lists four participants at risk for other adverse events and four participants with other adverse events. The reported number of deaths is zero. These are descriptive counts for the single study group.
The counts do not indicate which adverse events occurred, when they occurred, how severe the non-serious events were, or whether an event was considered related to treatment. The record lists no top serious-event terms. It also does not report a comparator group, so the figures cannot be used to compare adverse-event experience across treatment strategies.
In general, adverse-event counts depend on definitions, the observation period, and completeness of follow-up and reporting. The registry record does not provide a detailed account of these elements. The counts should therefore be read narrowly as the reported group totals, not as a complete characterization of safety or as evidence about comparative risk.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a phase 3, open-label, single-group study evaluated oral avatrombopag 60 mg in adults with thrombocytopenia scheduled for surgery. It identifies the intended primary endpoint: the proportion achieving a platelet count >100 x 10^9 platelets/L on procedure day, from baseline to 10-13 days. It also reports four participants enrolled and several descriptive adverse-event counts.
The record does not report the primary endpoint result. It therefore does not show how many participants reached the platelet threshold, what the estimated proportion was, or how precise that estimate might be. No confidence interval or primary-outcome analysis is reported. The endpoint definition alone cannot establish the observed platelet response.
The design also does not support a treatment comparison. There is no comparator group, and the record describes the study as single group with allocation not applicable. Even if an outcome estimate were available, it would describe participants in this group rather than quantify how outcomes differed from another treatment or from no treatment. This limitation is separate from the absence of the primary result.
The adverse-event figures provide a limited description of reported counts among the four participants at risk in the group. Without event terms, timing, fuller follow-up information, or a comparator, they cannot establish comparative safety or characterize the complete range of possible events.
In short, the record is informative about the study’s stated question and structure, but does not provide the efficacy result required to answer that question. The termination status and small enrollment are relevant context; the reason for termination and the implications for outcome collection are not reported in the registry record. No conclusion about treatment benefit or lack of benefit can be drawn from the endpoint definition or the available counts alone.
13. Why This Trial Matters Statistically
This study illustrates the difference between a registered endpoint and a reported result. A clearly described outcome gives readers a definition of what the investigators intended to measure, but statistical interpretation requires the observed data and an account of how those data were analyzed. Here, the platelet-count threshold and timeframe are recorded, while the primary-outcome estimate and its uncertainty are not reported in the registry record.
It also highlights how design affects the question a result can answer. A single-group study can describe observed outcomes in participants receiving an intervention, but it does not provide a concurrent comparator for estimating a treatment difference. That distinction matters even when an endpoint is objective: measurement objectivity does not remove the need for a comparison when the question concerns relative effects.
The enrollment of four participants and the terminated status further emphasize the need to understand who contributed data and why the study ended. The record does not report the number analyzed for the primary outcome or the reason for termination. Without these details, readers cannot determine whether the enrolled group and the outcome population were the same or assess how study completion affected the available evidence.
Finally, the record demonstrates why descriptive safety counts and efficacy analyses should be kept distinct. Counts of adverse events can document what was recorded in a group, but they do not replace a primary-outcome analysis or support a comparative safety estimate. Careful reading means separating what the registry records directly from what remains unreported.
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 is that the registry record does not report a primary-outcome result. Although the endpoint is defined, no participant count meeting the platelet threshold, estimated proportion, confidence interval, or statistical analysis is provided. This prevents quantitative assessment of the stated primary question.
The study was single group, open label, and had no comparator. Its design therefore does not allow a direct comparison with another treatment strategy. The record reports enrollment of four participants, but does not state how many were analyzed for each outcome or whether all enrolled participants underwent a procedure and had a procedure-day platelet measurement.
The study status is terminated, but the reason for termination and any effect on data collection are not reported in the registry record. The protocol’s intended enrollment and the rationale for the study design are also not reported. It is not possible to determine from the available information whether the recorded enrollment reflects the full planned study population.
Other relevant details are absent: outcome analysis methods, analysis populations, missing-data handling, interim analyses, multiplicity procedures, and the rationale for the platelet threshold. The safety record provides counts but no event terms or timing, and no serious-event terms are listed. These omissions limit interpretation of both the primary outcome and the adverse-event experience.
These limitations are specific to the information recorded and should not be filled in by assumption. They do not establish what the unreported data would show; they define what cannot be assessed from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Avatrombopag for the Treatment of Thrombocytopenia in Adults Scheduled for a Surgical Procedure — NCT03326843.
- Registry record last updated 2020-04-15; status last verified 2018-05.
- Results first posted 2020-04-15.
- 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
NCT03326843 is a phase 3, open-label, multicenter, single-group study of oral avatrombopag 60 mg in adults with thrombocytopenia scheduled for surgery. The primary endpoint was the proportion achieving a platelet count >100 x 10^9 platelets/L on procedure day, from baseline to 10-13 days. The study began on 2018-03-26, had a primary completion date of 2019-02-25, and is listed as terminated. Enrollment was four.
The registry record does not report a primary-outcome result or an outcome analysis. In the avatrombopag 60 mg group, zero serious adverse events were recorded among four participants at risk, four participants were recorded with other adverse events among four at risk, and zero deaths were reported. The reason for termination, analysis populations, missing-data methods, and detailed adverse-event terms are not reported in the registry record.