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 Real World Study of Bamlanivimab in Participants With Mild-to-Moderate Coronavirus Disease 2019 (COVID-19) (NCT04701658), a non-randomized phase 2 study. The primary outcome is Percentage of Participants Who Experience COVID-19 Related Hospitalization or Death From Any Cause.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04701658 |
| Phase | Phase 2 |
| Condition | COVID-19 |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 109 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Eli Lilly and Company |
| Results posted | Yes |
2. Clinical Question
Population
Participants with mild-to-moderate COVID-19 at high risk for progressing to severe illness. The primary-outcome population is described as all participants who received a single dose of bamlanivimab.
Intervention
A single 700 milligram intravenous infusion of bamlanivimab.
Comparator
The original plan included matched controls receiving standard of care at a local medical center. The registry record says low enrollment led to an amendment to a single-arm study; no matched controls were utilized.
Primary question
What percentage of participants experienced COVID-19-related hospitalization or death from any cause from baseline through Days 29, 60, and 90?
The clinical question is therefore framed as an outcome frequency among treated participants, rather than as a treatment-versus-control contrast. The original study description proposed evaluating real-world effectiveness by matching treated participants with similar patients receiving other treatment. That comparison would have been intended to put outcomes in context, but the amended study did not use a control group. The registry record consequently cannot establish whether the outcome frequency differed from what would have occurred under standard care.
The primary endpoint combines COVID-19-related hospitalization with death from any cause. Hospitalization is defined in the record as at least 24 hours of acute care. The record also lists COVID-19-related hospitalization and COVID-related emergency department visits as secondary outcomes. It does not report numerical results for these outcomes or for the primary endpoint. The study followed participants through the listed time points, with participation described as lasting about 3 months and assessments conducted through study-site visits, phone contact, or medical-record review.
3. Trial Design
This was a Phase 2 prospective cohort study with non-randomized allocation, no masking, and a parallel model. The registry record lists an enrollment of 109 and marks the study as completed. It gives a start date of 2021-02-01 and a primary completion date of 2021-06-22. The sponsor was Eli Lilly and Company.
The study was originally designed to include a matched control arm. The control description specifies matched participants receiving standard of care, but also records that the study was amended because of low enrollment and became a single-arm study. No matched controls were utilized. The treated arm received a single 700 milligram intravenous infusion of bamlanivimab. Thus, despite the original comparative objective, the completed study record does not document a concurrent control group for estimating a treatment contrast.
The primary endpoint was the percentage of participants experiencing COVID-19-related hospitalization or death from any cause. The observation period is described as baseline through Days 29, 60, and 90. The endpoint population is defined as all participants who received a single dose of bamlanivimab. The registry also names hospitalization and emergency department visits as secondary outcomes. It lists three outcome measures in total, but reports no analyses in the record.
Prospective follow-up can organize observations around a defined treatment and outcome period, but it does not by itself remove differences between treated participants and a comparison population. In this study, the absence of matched controls means the record supports describing outcomes among treated participants only, to the extent numerical outcome results are reported. It does not support a randomized or matched estimate of comparative effectiveness. The registry record does not report the matching procedures originally intended, detailed eligibility criteria, or a statistical analysis plan.
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 | Bamlanivimab 700 Milligram (mg) |
|---|---|
| STARTED | 109 |
| Received Single Dose of Bamlanivimab | 109 |
| COMPLETED | 103 |
| NOT COMPLETED | 6 |
Reasons for not completing this period:
| Reason | Bamlanivimab 700 Milligram (mg) |
|---|---|
| Lost to Follow-up | 6 |
Analysis population for the primary outcome, as defined in the registry: All participants who received single dose of Bamlanivimab.
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: All participants who received single dose of Bamlanivimab.
| Characteristic | Unit | Bamlanivimab 700 mg |
|---|---|---|
| Participants analysed | 109 | |
| Age, Continuous | years | 55.40 (SD 15.34) |
| Sex: Female, Male: Female | Participants | 61 |
| Sex: Female, Male: Male | Participants | 48 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 50 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 55 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 4 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 3 |
| Race (NIH/OMB): Asian | Participants | 2 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 1 |
| Race (NIH/OMB): Black or African American | Participants | 6 |
| Race (NIH/OMB): White | Participants | 83 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 13 |
| Region of Enrollment: United States | Participants | 109 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants Who Experience COVID-19 Related Hospitalization or Death From Any Cause, measured over Baseline through Days 29, 60, and 90.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | Percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants who experienced COVID-19-related hospitalization or death from any cause. The registry defines hospitalization as at least 24 hours of acute care and gives the observation period as baseline through Days 29, 60, and 90. The stated population is all participants who received a single dose of bamlanivimab.
This is a binary outcome: each participant either meets the endpoint definition during the specified period or does not. Reporting a percentage can describe how frequently the defined event occurred in the observed treatment group. Combining hospitalization with death creates a broader endpoint than hospitalization alone, while the all-cause wording means death is included regardless of its stated cause. These features affect what the endpoint represents and should be kept in mind when interpreting any estimate.
As a general statistical point, a confidence interval around a percentage communicates the uncertainty associated with estimating an event frequency from a sample. Its width depends in part on the amount of information and the number of observed events. The registry record identifies a 95% confidence interval as the dispersion measure for the primary endpoint, but it does not report the primary endpoint estimate or its interval. It therefore does not allow the event frequency or its precision to be assessed from the registry record.
The endpoint may be clinically interpretable as an event occurrence, but a single-arm percentage does not measure what would have happened to the same participants under another treatment. A comparative question requires an appropriate comparator and analysis. Since the amended study used no matched controls, its primary endpoint cannot by itself quantify a difference attributable to bamlanivimab.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The most important interpretive feature is the change from the original matched-control plan to a single-arm study. Although the title and original description refer to matched controls and real-world effectiveness, the arm description states that no matched controls were utilized after an amendment prompted by low enrollment. The resulting design can describe outcomes in the bamlanivimab arm, but it cannot provide a direct estimate of outcomes relative to standard care within this study.
The registry identifies the primary endpoint, its population, follow-up period, and intended uncertainty measure. It does not give the number or percentage of participants meeting the primary endpoint, nor a 95% confidence interval. It also lists no analyses. The registry record therefore does not report an observed primary result to interpret. The same limitation applies to the named secondary outcomes: hospitalization and emergency department visits are listed, but their numerical results are not reported in the registry record.
For a binary endpoint, the observed percentage would describe the proportion of the defined analysis population experiencing the event, while a confidence interval would communicate uncertainty about that estimate. General statistical interpretation should distinguish the estimate from its precision: a point estimate alone does not show how uncertain it is, and an interval does not address possible bias or confounding. In this record, neither the primary estimate nor its interval is available, so no conclusion about the observed frequency or precision can be drawn.
Even if an event percentage were available, a single-arm observation would not establish that treatment caused the outcome. Participants may differ in health status, care, or other factors that also influence outcomes. A comparator can help contextualize such observations, but non-randomized comparisons can still be affected by selection and residual confounding. Here, the planned matching was not used, so there is no registry-reported control outcome against which to make a comparison.
The adverse-event information is separate from the primary efficacy endpoint. The registry reports serious adverse events and other adverse events for the bamlanivimab group, including zero deaths. Those figures describe recorded events in the treated group; without a control group, they do not establish how event occurrence compares with standard care. Nor do the reported categories alone determine whether an event was caused by treatment.
Overall, the record establishes the study's intended question and its amended single-arm structure, but not the primary or secondary outcome estimates. The registry information supports a design-level interpretation and a limited description of safety counts. It does not support a comparative effectiveness estimate, a treatment-effect conclusion, or an assessment of primary-outcome precision.
9. Statistical Methods Explained
What does a percentage endpoint represent?
For a binary outcome, a participant is classified according to whether the event definition was met during the specified follow-up. The percentage is a summary of the observed frequency in the stated population. Here, the primary endpoint combines COVID-19-related hospitalization and death from any cause, with hospitalization defined as at least 24 hours of acute care. The registry identifies the treated population and the follow-up period, but does not report the endpoint count or percentage. Without those results, the endpoint's observed frequency cannot be described.
As a general statistical explanation, a percentage is an estimate of an underlying event frequency, not a guarantee that the same frequency would be observed in another group or setting. It is also distinct from a treatment effect. A treatment effect is comparative: it expresses how outcomes differ between treatment strategies under a defined analysis. A single-arm event percentage has no internal comparator and therefore does not estimate that contrast.
What does a confidence interval add?
The registry specifies a 95% confidence interval as the primary endpoint's dispersion measure. In general, a confidence interval communicates the statistical uncertainty around an estimate under the assumptions of the method used. It helps readers assess precision: narrower intervals generally indicate more precise estimates, while wider intervals indicate greater uncertainty. The interval does not correct for bias, confounding, outcome misclassification, or missing data. Those concerns require design and analysis information beyond the interval itself.
No primary endpoint estimate or confidence interval is reported in the registry record. The stated interval type is not enough to recover either value. It is also not possible to assess whether the primary estimate was based on all participants with adequate follow-up, how incomplete observations were handled, or whether the interval method accounted for any such issues.
Why does the lack of a comparator matter?
The original plan described matched controls, but the record says the study was amended to a single-arm study because of low enrollment and that no matched controls were utilized. Matching is a way to make groups more comparable on selected characteristics; it does not automatically ensure that all relevant differences are controlled. More fundamentally, there are no matched control outcomes in this study record to compare with the bamlanivimab arm.
In a non-randomized study, treatment assignment is not based on random allocation. As a general principle, differences between treated and untreated groups may reflect both treatment and characteristics that influence treatment selection or outcome. Randomization is one way to balance such factors on average, while a carefully conducted observational analysis may attempt to address measured confounders. Neither a randomized comparison nor a matched analysis is reported. The record therefore permits description of the treated cohort, but not a causal contrast with standard care.
What do the planning illustrations mean?
Sample-size planning is different from an observed trial result. The planning assumptions described for the illustrations specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. For time-to-event planning, the stated approach uses the total number of events, while other planning displays concern participants per arm. These are planning illustrations based on an observed effect, not evidence that the trial had a particular probability of finding a result.
General statistical interpretation should not confuse planning illustrations with observed power. A power calculation describes design performance under assumed conditions; it does not measure the probability that the observed finding is true. The registry record lists no analyses and no primary outcome result, so the illustrations cannot substitute for a reported estimate, interval, or comparative analysis. The record also does not report the trial's own sample-size justification, so the planning assumptions should not be treated as the study's protocol rationale.
How should the event counts be read?
The safety record distinguishes serious adverse events from other adverse events and provides the group size at risk and the number affected for each category. Counts and denominators describe the recorded events in that group. General statistical interpretation requires attention to the event definitions, observation period, completeness of reporting, and whether participants could contribute more than one event. Those details are not all reported in the registry record. A count of affected participants is not necessarily the same as a count of individual event episodes.
Safety counts in a single treatment group are descriptive. Without a concurrent control group, they do not determine whether the frequency is higher or lower than it would have been under another care strategy. A recorded event may also occur after treatment without being caused by treatment. Causal attribution requires more information than temporal occurrence alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry record names a primary endpoint and two secondary outcomes: COVID-19-related hospitalization and COVID-related emergency department visits. It lists three outcome measures in total, but reports no analyses. A statistical multiplicity plan—such as whether outcomes were prioritized, adjusted, or treated as descriptive—is not reported in the registry record. Without that information, readers cannot assess how the study intended to address the possibility of chance findings across multiple outcomes or time points.
The primary endpoint is described across baseline through Days 29, 60, and 90. The record does not clarify whether these time points were analyzed separately, whether a single cumulative measure was intended, or how repeated observations were handled. Any such details about the analysis are not reported in the registry record. The endpoint description should not be taken as evidence that a particular repeated-measures method was used.
The primary population is identified as all participants who received a single dose of bamlanivimab. However, the registry does not report the number included in the primary outcome analysis, the treatment of participants with incomplete follow-up, or the handling of missing outcome information. It also does not report an intention-to-treat analysis population or a method for imputing missing values. These omissions limit assessment of whether the endpoint estimate, if available, would represent all treated participants or only those with observed outcome data.
More broadly, the record does not report a statistical analysis plan, an interim-analysis approach, or a sample-size justification. These items should not be inferred from the endpoint listing or from planning illustrations. Because no outcome analyses are listed and numerical primary and secondary results are absent, neither multiplicity handling nor missing-data effects can be evaluated from the registry record.
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 |
|---|---|---|---|
| Bamlanivimab 700 mg | 2 | 109 | 1.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Bamlanivimab 700 mg | 0 of 109 |
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 |
|---|---|
| Bamlanivimab 700 mg | 9 of 109 |
Most frequent serious adverse event terms
| Event term | Organ system | Bamlanivimab 700 mg |
|---|---|---|
| Cholelithiasis | Hepatobiliary disorders | 1 of 109 |
| End stage renal disease | Renal and urinary disorders | 1 of 109 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Bamlanivimab 700 mg |
|---|---|---|
| Infusion site extravasation | General disorders | 5 of 109 |
| Tachycardia | Cardiac disorders | 1 of 109 |
| Vision blurred | Eye disorders | 1 of 109 |
| Headache | Nervous system disorders | 1 of 109 |
| Paranasal sinus hypersecretion | Respiratory, thoracic and mediastinal disorders | 1 of 109 |
| Pharyngeal swelling | Respiratory, thoracic and mediastinal disorders | 1 of 109 |
| Rash | Skin and subcutaneous tissue disorders | 1 of 109 |
Serious events with the highest arm-level rate: cholelithiasis (0.9%), end stage renal disease (0.9%).
The registry reports safety information for the Bamlanivimab 700 mg group. The number at risk is 109 for serious adverse events and 109 for other adverse events. Two participants were reported as affected by serious adverse events, and 9 by other adverse events. The record reports zero deaths. It lists cholelithiasis and end stage renal disease among the top serious-event terms, each at 0.9%.
These are descriptive figures for the treated group, not a comparison with standard care. The record says no matched controls were utilized, so it does not provide a control-group safety frequency. The serious-event terms and percentages identify reported categories; they should not be read as evidence that bamlanivimab caused those conditions. The registry record does not report further detail on event timing, attribution, severity criteria, or how repeated events were counted.
General statistical interpretation distinguishes the number of participants affected from the number of event episodes. The listed affected counts describe participants, while the record does not specify whether an individual could contribute multiple events within a category. The safety figures also do not establish the absence of risk: they are observations from the study population and follow-up, not proof about outcomes beyond them. The registry record does not provide a comparative safety analysis.
12. What the Result Does, and Does Not, Mean
The registry record documents a prospective cohort study of bamlanivimab in participants with mild-to-moderate COVID-19 at high risk for progression to severe illness. The study was listed as Phase 2, non-randomized, unmasked, and parallel. Participants in the treatment group received a single 700 milligram intravenous infusion. The original design included matched controls receiving standard of care, but the record says low enrollment led to an amendment to a single-arm study and no controls were used.
That design change determines what can be learned from the record. A single treated group can be used to describe observed outcomes, if those results are reported. It cannot, by itself, show how outcomes compare with those under another treatment strategy. Even a difference from an external reference would not automatically be attributable to treatment, because groups may differ in characteristics that affect outcomes. No matched-control comparison is reported.
The primary outcome is clearly defined as COVID-19-related hospitalization or death from any cause, with hospitalization requiring at least 24 hours of acute care. The registry specifies a 95% confidence interval but does not report the outcome estimate or interval. It also lists two secondary outcomes without numerical results and reports no analyses. Therefore, the registry record does not establish the observed primary endpoint frequency, its precision, or a comparative treatment effect.
The serious and other adverse-event counts provide descriptive safety information for the treated group, including the reported serious-event terms and zero deaths. They are not a comparison with another group and do not prove that events were or were not caused by treatment. Missing information about event details and analysis procedures further limits interpretation.
In general, an outcome estimate, its uncertainty, the design used to obtain it, and the completeness of follow-up all matter to interpretation. Here, the design and endpoint definitions are available, but outcome analyses and key analysis details are not. The record therefore supports a description of the study's structure and reported safety counts, not a conclusion about comparative effectiveness or a treatment recommendation.
13. Why This Trial Matters Statistically
This study is statistically informative because its registry record makes a distinction between the original comparative plan and the study that was ultimately conducted. The original description proposed matched controls, while the amended design was single-arm and used no matched controls. Recognizing that change prevents the study's original comparative aim from being mistaken for an observed treatment-versus-control analysis.
The endpoint also illustrates why precise definitions matter. The primary measure combines COVID-19-related hospitalization and death from any cause, and the hospitalization threshold is at least 24 hours of acute care. These choices define which events count and what the resulting percentage would represent. The specified observation period extends through Days 29, 60, and 90, but the record does not state how those time points were incorporated into an analysis.
The record further illustrates the difference between an endpoint definition and an endpoint result. A named outcome and a stated confidence-interval measure do not reveal the observed frequency or its precision when the estimate and interval are absent. The registry lists no analyses, so an intended outcome question should not be treated as evidence that the question was answered in the posted results.
Finally, the safety information shows the limits of descriptive counts. Serious and other adverse events can be reported for a treated group, but without a comparator those counts do not quantify a relative risk. In general, study design, analysis, uncertainty, and outcome completeness must be considered together. This record offers a useful example of why those elements should be separated when interpreting a clinical study.
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 principal limitation is the absence of the planned matched-control group. The registry explicitly says that the study was amended to a single-arm design because of low enrollment and that no matched controls were utilized. The study therefore cannot supply an internal comparison with standard care, despite the original matched-control objective and wording in the study description.
The registry record does not report numerical results for the primary endpoint or either named secondary outcome. It gives the primary endpoint definition and the intended 95% confidence interval measure, but not the estimate or interval. It also lists no analyses. Consequently, the posted record does not permit assessment of outcome frequency, statistical precision, or a treatment contrast.
Important analysis details are not reported in the registry record. These include the statistical analysis plan, sample-size justification, analysis population details beyond the stated primary population, handling of missing outcomes, multiplicity procedures, and how observations across the stated follow-up time points were treated. The intended matching procedures are also not reported, though the record confirms that matched controls were not used.
The study was non-randomized and unmasked. In general, non-randomized treatment assignment may be associated with participant characteristics that also affect outcomes, while lack of masking can influence some aspects of assessment or reporting. These are design considerations, not proof that bias occurred. The available record does not allow their effects to be quantified. Safety reporting is likewise limited to descriptive figures without a control comparison or detailed event information. These constraints mean the record should be read as a limited account of study design and reported safety data rather than a comparative evaluation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Real World Study of Bamlanivimab in Participants With Mild-to-Moderate Coronavirus Disease 2019 (COVID-19) — NCT04701658.
- Registry record last updated 2021-11-16; status last verified 2021-11.
- Results first posted 2021-11-16.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT04701658 is a completed Phase 2 prospective cohort study of bamlanivimab in participants with mild-to-moderate COVID-19 at high risk for progression to severe illness. It was non-randomized, unmasked, and parallel, with an enrollment of 109. The treatment group received a single 700 milligram intravenous infusion.
The original study plan included matched controls receiving standard of care. The registry record says low enrollment led to an amendment to a single-arm study and that no matched controls were utilized. The primary endpoint was COVID-19-related hospitalization or death from any cause from baseline through Days 29, 60, and 90; hospitalization was defined as at least 24 hours of acute care.
The record lists two secondary outcomes and reports descriptive adverse-event information, including zero deaths. It does not report numerical results for the primary or secondary outcomes, lists no analyses, and does not provide a comparative treatment estimate.