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 GANfort® in Patients With Primary Open Angle Glaucoma or Ocular Hypertension Who Are Insufficiently Responsive to Monotherapy (NCT01628601), a registered phase not stated study. The primary outcome is Change From Baseline in Intraocular Pressure (IOP).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01628601 |
| Phase | Phase not stated |
| Condition | Glaucoma, Open-Angle, Ocular Hypertension |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 392 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Allergan |
| Results posted | Yes |
2. Clinical Question
Population
Patients diagnosed with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) who were insufficiently responsive to monotherapy. The record describes 392 enrolled patients and specifies that the primary outcome population comprised enrolled patients with complete data for that measure.
Intervention
GANfort®, a fixed combination of 0.3 mg bimatoprost and 5 mg timolol, prescribed by each patient’s physician. The dose was determined by the physician before study entry.
Comparator
No concurrent control group or alternative treatment is described. This is an observational study of patients prescribed GANfort®; the registry record does not describe randomized allocation.
Primary question
What was the change from baseline in intraocular pressure (IOP), measured in millimeters of mercury, at 18 weeks among enrolled patients with complete data? The registry record defines the outcome and measurement times but does not report its numerical result.
The clinical question is descriptive rather than a direct comparison of treatment strategies. The study concerns patients whose response to monotherapy was considered insufficient and who were prescribed the fixed combination in routine physician-directed care. Because no concurrent comparator is described, the record does not establish how IOP would have changed over the same period under another treatment or without the combination.
The question also has a defined analysis population: enrolled patients with complete data for the primary measure. The record does not state how many patients met that criterion. It therefore does not establish whether the primary outcome reflects all enrolled patients or a smaller subset, nor does it give the numerical change or its uncertainty. Those omissions limit interpretation of the primary question to the outcome’s stated definition and measurement schedule.
3. Trial Design
This was an observational study sponsored by Allergan. The registry describes patients with POAG or OHT who were insufficiently responsive to monotherapy and whose physicians prescribed GANfort®. Enrollment was 392. The study began in 2010-05, had primary completion in 2011-06, and is recorded as completed.
The intervention was the fixed combination of 0.3 mg bimatoprost and 5 mg timolol. Treatment was prescribed by the physician, and the dose was determined before study entry. The registry record does not describe randomization, a protocol-assigned dose, or a control group. The listed arm is “POAG or OHT,” which represents the treated patient group rather than a like-for-like treatment comparison.
The primary outcome was change from baseline in IOP, with measurements at baseline and 18 weeks. The record describes the summary measure as a median with an inter-quartile range. It defines a negative change as an improvement. The primary analysis population is described as enrolled patients with complete data for the outcome, but the number with complete data is not reported in the registry record.
Secondary outcomes concerned physician and patient assessments of tolerability using a 4-point scale, physician assessment of adherence, and the number of patients continuing with GANfort® after 18 weeks. The record lists 5 outcome measures overall but does not provide results for these secondary outcomes in the registry record for interpretation.
The registry record does not report further details of how patients were recruited, how treatment decisions were made, or how measurements were standardized. It also does not state an allocation method beyond the fact that the study was observational. These design features mean the central evidence is intended to describe outcomes among patients receiving physician-prescribed treatment, not to estimate a randomized treatment contrast.
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 | POAG or OHT |
|---|---|
| STARTED | 392 |
| COMPLETED | 351 |
| NOT COMPLETED | 41 |
Analysis population for the primary outcome, as defined in the registry: All enrolled patients with complete data for this outcome measure
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 | POAG or OHT |
|---|---|---|
| Participants analysed | 392 | |
| Age Continuous | Years | 67.22 (SD 13.14) |
| Sex/Gender, Customized: Female | Participants | 232 |
| Sex/Gender, Customized: Male | Participants | 155 |
| Sex/Gender, Customized: Missing Data | Participants | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Intraocular Pressure (IOP), measured over Baseline, 18 Weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | Millimeters of Mercury (mmHg) |
| Endpoint classification | not reduced to a single comparison |
IOP is a measurement of the fluid pressure inside the eye. The primary endpoint is change from baseline in IOP, expressed in millimeters of mercury, with assessment at baseline and 18 weeks. The registry defines a negative change from baseline as an improvement. The endpoint’s numerical result, however, is not reported in the registry record.
Change from baseline is used to describe how a measurement at follow-up differs from its starting value. In general, this can make the direction of change easier to interpret than a follow-up value alone, especially when the initial measurement is relevant to the outcome. It remains a within-person change, not by itself an estimate of what would have happened under a different treatment. Without a concurrent comparator, observed changes may reflect treatment and other influences, and the design cannot separate those explanations.
The record specifies the median and inter-quartile range as the summary statistics. In general, the median describes the central value after ordering observations, while the inter-quartile range describes the spread of the middle portion of the observed values. These summaries can be useful when a distribution is skewed or contains unusually high or low values. They do not, on their own, provide a confidence interval for the estimated change or show how many patients contributed data.
The defined analysis population includes enrolled patients with complete data for this outcome. The count in that population and the numerical median and inter-quartile range are not reported in the registry record, so the endpoint cannot be quantitatively interpreted in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically interpretable primary measure: change in IOP from baseline to 18 weeks. It also states how to read the direction of change: a negative value indicates an improvement. However, the numerical median change and inter-quartile range are not reported in the registry record. There is consequently no estimate to describe in terms of magnitude, distribution, or precision. A direction-of-change rule is not a result.
The study’s observational design is central to interpretation. Patients were prescribed GANfort® by their physicians, at a dose determined before study entry. No concurrent comparator or randomized allocation is described. Even if an outcome estimate were available, a before-and-after change in this treated group would not by itself show what caused the change. Other influences on IOP over the observation period could not be distinguished from treatment effects using a single treated group alone.
The registry defines the primary population as enrolled patients with complete data for the outcome. The number of patients with complete data is not reported in the registry record. If outcome availability differed among participants, the analyzed group could differ from the enrolled group in ways relevant to interpretation. The record does not provide enough detail to assess whether missing outcome data were limited or potentially consequential.
There are 5 outcome measures listed, including patient and physician assessments of tolerability, physician assessment of adherence, and continuation with GANfort® after 18 weeks. The numerical results for those measures are not reported in the registry record. Their definitions indicate that the study considered aspects of treatment experience in addition to IOP, but they do not establish the results of those assessments.
The safety record lists 1 serious adverse event among 392 at risk and no events in the other-event count. Dyspnoea is listed among the serious adverse event terms at 0.3%. These are descriptive registry counts; the record does not describe a comparison group that would allow comparative safety estimation. Deaths are not reported in the registry record.
Overall, the available information characterizes the population, treatment context, outcome definitions, and selected safety counts. It does not provide the primary endpoint estimate, uncertainty around that estimate, or a comparative treatment effect. Statistical interpretation should therefore focus on what the registry records and does not record, rather than inferring efficacy or causation from the study’s stated objective.
9. Statistical Methods Explained
The registry describes an observational study with a single treated group, a baseline measure, and an 18-week follow-up measure for the primary outcome. The stated primary summary is a median with an inter-quartile range. No numerical endpoint estimate, confidence interval, or p-value is reported in the registry record. The statistical concepts below explain how these methods are generally interpreted; they do not supply results absent from the record.
What does a change-from-baseline measure describe?
In general, a change score describes the difference between a follow-up measurement and a participant’s starting measurement. Here, the record specifies baseline and 18-week IOP assessments and states that a negative change indicates an improvement. A group summary of individual changes describes the observed participants’ movement from baseline. It does not, by itself, estimate the treatment effect relative to an untreated or differently treated group.
Change scores can be influenced by the starting value, measurement variability, and events during follow-up. In a controlled study, comparison of changes between groups can help distinguish the course in the treatment group from changes that might also have occurred under a comparator. That comparison is not described in this record. Thus, the endpoint definition does not turn an observational before-and-after assessment into a causal comparison.
Why report a median and inter-quartile range?
In general, the median is the middle observation when values are ordered. Unlike the mean, it is less affected by the magnitude of extreme observations. The inter-quartile range describes the spread between the central portions of the distribution. Reporting both can convey a typical observed change and variability without assuming that the data follow a symmetric, bell-shaped distribution.
These summaries do not convey every feature of the data. They do not show the full distribution, the number of observations included, or the precision of the estimated median. A confidence interval can quantify uncertainty around an estimate; in general, it expresses a range of values compatible with the data and the method’s assumptions. No confidence interval for the primary endpoint is reported in the registry record, and none can be inferred from the stated summary measure alone.
What does the observational design permit?
In general, random allocation helps balance measured and unmeasured characteristics between treatment groups, supporting a causal comparison. An observational study instead records treatment chosen in clinical practice. Treatment choice may be related to patient characteristics, disease status, prior response, or other factors. Those factors can also be related to outcomes. Without a suitable comparison and an analysis that addresses relevant confounding, an observed before-and-after change cannot be attributed solely to treatment.
The registry describes physician-prescribed treatment and a dose set before study entry, but does not report a statistical adjustment strategy or other details that would address confounding. It does not report a randomized comparison. The record therefore supports a descriptive reading of the treated cohort, not an estimate of the difference attributable to GANfort® compared with another course of care.
How should the planning illustrations be understood?
General sample-size calculations estimate how many participants may be needed under specified assumptions to detect a chosen effect with a chosen statistical procedure. The stated planning assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They also describe effects as fractions of the observed effect. These are planning illustrations based on the observed effect, not the trial’s own design justification. The registry record does not report the protocol’s sample-size justification.
Such illustrations are conditional on their assumptions. They do not establish that the original study was designed with those assumptions, nor that its observed results have a particular probability of being correct. Sample-size calculations are not “observed power,” and a planning value should not be interpreted as an observed study result. The registry record’s description does not provide a numerical primary outcome estimate in the registry record for this interpretation, so the study’s outcome magnitude and precision cannot be evaluated from that description.
What do the event counts show statistically?
Adverse-event counts are descriptive. The record lists serious adverse events and other adverse events for the treated group, with 392 participants at risk in each listed category. A count does not describe event timing, duration, severity beyond the registry classification, or causal attribution unless those details are separately reported. A percentage attached to an event term describes its recorded frequency in this registry record; it is not a comparative risk estimate.
For comparative safety inference, groups and methods for comparing their event rates would be needed. No concurrent comparator is described. The event information therefore documents what the registry lists, without establishing whether the treatment changed risk relative to another treatment or no treatment.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 5 outcome measures: the primary IOP measure and secondary measures concerning physician and patient tolerability assessments, physician assessment of adherence, and continuation with GANfort® after 18 weeks. When a study examines multiple outcomes, general statistical practice considers multiplicity: the chance of obtaining at least one apparently notable result can increase as more hypotheses are tested. Whether and how this concern was addressed depends on the prespecified analysis plan. The statistical plan, including any multiplicity adjustment or hierarchy of outcomes, is not reported in the registry record.
The record does not report p-values or numerical results for the primary or secondary measures in the registry record for interpretation. It is therefore not possible to assess the pattern of statistical evidence across outcomes or whether any adjustment was applied. No analysis plan or interim analysis description is reported in the registry record.
The primary outcome population is defined as enrolled patients with complete data for that measure. The number of participants with complete data is not reported in the registry record, nor are reasons for missing measurements, methods for handling missing data, or sensitivity analyses. In general, complete-case analyses use only participants with observed outcome data. Their interpretation can be affected if the availability of data is related to the outcome or to participant characteristics. The record does not establish whether that concern applies in this study.
The registry reports enrollment of 392, but the count contributing to the primary endpoint is not reported in the registry record. It also does not describe whether analyses used an intention-to-treat approach or another analysis population. As a result, the relationship between enrollment, follow-up, and the endpoint analysis cannot be assessed from the record’s stated information.
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 |
|---|---|---|---|
| POAG or OHT | 1 | 392 | 0.3% |
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 |
|---|---|
| POAG or OHT | 0 of 392 |
Most frequent serious adverse event terms
| Event term | Organ system | POAG or OHT |
|---|---|---|
| Dyspnoea | Respiratory, thoracic and mediastinal disorders | 1 of 392 |
Serious events with the highest arm-level rate: dyspnoea (0.3%).
The safety record lists 392 participants at risk for serious adverse events and 1 participant affected. It lists 392 at risk for other adverse events and 0 affected in that category. Dyspnoea appears among the serious adverse event terms at 0.3%. These are descriptive counts and a recorded percentage, not evidence of a comparative difference between treatments.
A count of participants affected is not the same as a count of all event episodes; the registry information does not clarify whether the count represents people, episodes, or both beyond its listed affected field. It also does not provide event timing, duration, clinical course, or details needed to assess causality. The serious event count should therefore be read as a record of reported events in the study group, not as proof that treatment caused or prevented an event.
No concurrent comparator is described, so these data do not estimate how serious or other adverse event occurrence compares with another treatment or with no treatment. Deaths are not reported in the registry record. The absence of a reported death figure should not be interpreted as a confirmed count of zero.
12. What the Result Does, and Does Not, Mean
The record establishes that an observational study enrolled 392 patients with POAG or OHT who were insufficiently responsive to monotherapy and were prescribed physician-directed GANfort®. Its primary outcome was change in IOP from baseline to 18 weeks, summarized using a median and inter-quartile range. The record states that a negative change indicates improvement. It does not report the numerical change or its spread in the information available for interpretation.
That absence matters: without the endpoint estimate, the magnitude and distribution of observed change cannot be described. Without an uncertainty interval, its precision cannot be assessed. The outcome definition alone does not establish that IOP changed in a particular direction or by a particular amount.
Even if a within-group change were reported, the observational design would limit causal interpretation. Physicians prescribed treatment and set the dose before study entry, and no concurrent comparator is described. A change during follow-up could reflect treatment as well as other influences. The record cannot establish what would have happened to the same population under an alternative treatment or without the combination.
The secondary measures indicate that tolerability, adherence, and continued treatment were also of interest. Their results are not reported in the registry record. The safety listing records a serious adverse event in 1 of 392 at risk and an other-event count of 0 among 392 at risk; it also lists Dyspnoea at 0.3%. Those figures describe registry entries and do not establish comparative safety or causation.
Accordingly, the record is informative about the study’s setting, treatment, follow-up, intended outcomes, and limited event counts. It does not provide a numerical primary outcome result or a controlled estimate of treatment effect. It should not be read as demonstrating that treatment did or did not produce a particular benefit or harm.
13. Why This Trial Matters Statistically
This study is statistically useful as an example of the distinction between a treatment outcome description and a treatment comparison. The stated endpoint is a change from baseline in IOP, but the observational design records patients receiving physician-prescribed treatment without a described concurrent control group. The design determines what can be inferred: an observed change, if reported, would describe the cohort, while a causal contrast would require a suitable comparison and assumptions addressing differences between groups.
The record also shows why an outcome definition is not a result. It gives the unit, summary measure, direction convention, and assessment times, but the numerical median and inter-quartile range are not reported in the registry record. Readers need both a result and information about its precision to judge what the data indicate. The complete-data analysis population is specified, while its size and missing-data handling are not reported.
Multiple listed outcomes raise a further general issue: interpretation across several measures depends on a prespecified statistical plan, including how multiplicity is handled. That plan is not reported in the registry record. The record’s planning assumptions are distinct from the study’s own design justification and do not substitute for a reported analysis plan or outcome estimate.
Finally, the adverse-event figures illustrate the limits of uncontrolled safety counts. They document reported events in the treated group, but without a comparator they do not quantify a treatment-related increase or decrease. The record is therefore a useful reminder to separate what is measured, what is reported, and what the design can support.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The principal limitation is that the numerical primary endpoint result is not reported in the registry record. Although the endpoint, summary measure, unit, and assessment times are specified, the median change and inter-quartile range are unavailable for interpretation. The record therefore does not permit an assessment of the observed magnitude or variability of IOP change.
The study is observational, with treatment prescribed by physicians and dose determined before entry. No concurrent comparator or randomized allocation is described. This prevents a direct like-for-like estimate of the outcome under GANfort® versus another treatment strategy. Potential differences in patient characteristics, clinical decisions, and events during follow-up cannot be separated from treatment effects on the basis of the information reported.
The complete-data population is specified for the primary outcome, but its size is not reported. The record also does not report reasons for missing data, methods for handling missingness, or sensitivity analyses. It is therefore unclear how representative the measured group was of the 392 enrolled patients.
Results for the secondary outcomes are not reported in the registry record. The statistical analysis plan, multiplicity approach, and any interim analyses are also not reported. The record does not provide the protocol’s sample-size justification. Deaths are not reported in the registry record. These limitations restrict assessment of outcome completeness, statistical precision, and the robustness of any treatment interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: GANfort® in Patients With Primary Open Angle Glaucoma or Ocular Hypertension Who Are Insufficiently Responsive to Monotherapy — NCT01628601.
- Registry record last updated 2012-09-24; status last verified 2012-08.
- Results first posted 2012-09-24.
- 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
NCT01628601 is a completed observational study sponsored by Allergan. It enrolled 392 patients with POAG or OHT who were insufficiently responsive to monotherapy and prescribed GANfort®, a fixed combination of 0.3 mg bimatoprost and 5 mg timolol. The physician determined the dose before study entry. The study began in 2010-05 and reached primary completion in 2011-06.
The primary outcome was change from baseline in IOP at 18 weeks, summarized as a median with an inter-quartile range. A negative change was defined as an improvement. The numerical primary result and the number of participants with complete outcome data are not reported in the registry record. Secondary outcomes addressed tolerability, adherence, and continuation with treatment. No concurrent comparator is described, and the registry record does not report a numerical result for the listed outcomes.