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 HORIZON: A Phase II Study to Evaluate the Safety and Efficacy of Two Doses of GT005 (NCT04566445), a randomized phase 2 study. The primary outcome is The Change From Baseline to Week 72 in Geographic Atrophy (GA).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04566445 |
| Phase | Phase 2 |
| Condition | Dry Age-related Macular Degeneration |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 255 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Gyroscope Therapeutics Limited |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned subjects with geographic atrophy (GA) secondary to age-related macular degeneration. The primary-outcome population is described as the Full Analysis Set: participants with a valid measurement and without a protocol deviation with impact. The registry record does not report further eligibility details or the number included in that analysis population.
Intervention
Participants were assigned to a single subretinal injection of GT005 at either the medium dose [5E10 vg] or high dose [2E11 vg]. The brief study summary and official title identify these as the treatment interventions under evaluation. The registry record does not give further administration details.
Comparator
The comparator was untreated control. The registry record describes three arms: GT005 medium dose, GT005 high dose, and untreated control. It records overall enrollment of 255 but does not provide allocation counts by arm for the primary-outcome analysis.
Primary question
The primary outcome was change from baseline to Week 72 in GA area, measured in mm^2 by fundus autofluorescence. The clinical question was whether the measured change differed across the GT005 dose arms and untreated control. The record does not report a single estimate or statistical comparison answering that question, so the direction and precision of any primary-outcome difference cannot be assessed from the registry record.
3. Trial Design
HORIZON (NCT04566445) was a Phase II randomized, controlled, parallel-group study sponsored by Gyroscope Therapeutics Limited. It evaluated two GT005 doses, administered as a single subretinal injection, against untreated control in people with GA secondary to dry age-related macular degeneration. The registry record gives enrollment as 255. It lists the study status as terminated, with a start date of 2020-09-28 and primary completion on 2024-06-10.
The registry classifies allocation as randomized and the model as parallel. Its masking field says quadruple, while the official title describes the study as open-label and outcomes-assessor masked. These descriptions do not match on their face; the registry record does not explain the difference or specify which roles were masked in practice. The masking arrangement should therefore be interpreted cautiously rather than reconstructed from the labels.
The study had three arms: GT005 medium dose [5E10 vg], GT005 high dose [2E11 vg], and untreated control. Random allocation can help balance measured and unmeasured participant characteristics across groups, but it does not by itself establish that groups remained comparable after enrollment or that missing outcome measurements were handled without bias. The record does not report the randomization method, allocation concealment procedures, or arm-specific enrollment figures for the primary analysis.
The primary outcome was change from baseline to Week 72 in GA measured by fundus autofluorescence. The listed measurement schedule includes baseline and Weeks 12, 24, 36, 48 and 72. Secondary outcomes include GA at Week 96, adverse events, GA morphology, visual acuity, low-luminance letter count, and reading performance. The record describes 11 outcome measures and 24 analyses. It does not provide a full protocol or a detailed 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.
Before assignment: The study design with 3 arms was the same for both Stage 1 and 2. Analysis was performed following the statistical analysis plan to combine Stage 1 and 2 results, and to report results per the 3 unique treatment arms.
Overall Study
| Stage | GT005 Medium Dose [5E10 vg] | GT005 High Dose [2E11 vg] | Untreated Control |
|---|---|---|---|
| STARTED | 87 | 86 | 82 |
| Stage 1 (Foveal and Non-foveal Geographic Atrophy) | 64 | 62 | 61 |
| Stage 2 (Non-foveal Geographic Atrophy) | 23 | 24 | 21 |
| COMPLETED | 54 | 51 | 35 |
| NOT COMPLETED | 33 | 35 | 47 |
Reasons for not completing this period:
| Reason | GT005 Medium Dose [5E10 vg] | GT005 High Dose [2E11 vg] | Untreated Control |
|---|---|---|---|
| Death | 4 | 1 | 1 |
| Lost to Follow-up | 3 | 1 | 1 |
| Study terminated by sponsor | 11 | 17 | 32 |
| Withdrawal by Subject | 12 | 14 | 13 |
| Randomized but not treated due to AE | 2 | 1 | 0 |
| Adverse Event | 1 | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Full Analysis Set - for participants with a valid measurement without a protocol deviation with impact.
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 | GT005 Medium Dose [5E10 vg] | GT005 High Dose [2E11 vg] | Untreated Control | Total |
|---|---|---|---|---|---|
| Participants analysed | 87 | 86 | 82 | 255 | |
| Age, Continuous | Years | 77.6 (SD 7.33) | 77.6 (SD 7.60) | 77.8 (SD 6.83) | 77.7 (SD 7.24) |
| Sex: Female, Male: Female | Participants | 52 | 61 | 53 | 166 |
| Sex: Female, Male: Male | Participants | 35 | 25 | 29 | 89 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 1 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 87 | 80 | 80 | 247 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 5 | 2 | 7 |
6. Primary Endpoint
The registry lists the primary outcome as The Change From Baseline to Week 72 in Geographic Atrophy (GA), measured over Baseline, Weeks 12, 24, 36, 48 and 72.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | Standard Error |
| Unit | mm^2 |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was change from baseline to Week 72 in the area of geographic atrophy, measured in mm^2. GA area was assessed by fundus autofluorescence (FAF), an imaging method used to measure the extent of the affected retinal area. The record lists measurement time points at baseline and Weeks 12, 24, 36, 48 and 72, while the primary endpoint specifically focuses on change through Week 72.
Change from baseline is used to express how a measurement at follow-up differs from the participant’s starting measurement. In general, this can make the treatment comparison focus on progression during follow-up rather than on the final measurement alone. A continuous area measure also retains information about the size of change across participants, rather than reducing it to a yes-or-no outcome. These are general features of continuous change endpoints, not evidence about the analysis choices made in this trial.
The registry identifies the reported parameter as a least-squares mean and its dispersion as a standard error. A least-squares mean is an adjusted mean from a statistical model; the registry record does not specify the model or covariates used. A standard error describes the precision of an estimated mean, not the spread of individual participants’ measurements. The posted record does not give a primary-outcome estimate, confidence interval, or test result that would allow the magnitude, direction, or precision of the Week 72 comparison to be evaluated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the intended comparison: change in GA area through Week 72 among the two GT005 dose groups and untreated control. It also establishes that the primary measure was obtained by fundus autofluorescence and was expressed as change from baseline. These details define the clinical and statistical question, but they are not themselves evidence of an outcome difference.
A primary-outcome result needs more than the name of the endpoint. To interpret a treatment contrast, readers ordinarily need an estimate of the difference between groups, a measure of uncertainty such as a confidence interval, and information about the analysis population and model. The registry record does not report a single primary-outcome comparison: its notes indicate that the outcome has several categories or time points and was not reduced to one comparison. Therefore, the direction and size of a primary-outcome contrast, and how precisely it was estimated, cannot be determined from this record.
The endpoint is continuous. In general, a group mean can describe average change, while participant-level variability indicates how much responses differ among people. A group mean does not imply that every participant experienced the same change. Similarly, a statistically estimated difference is not automatically a measure of clinical importance; interpretation depends on the scale, uncertainty, context, and prespecified criteria. The registry record does not report such criteria or a threshold for an important difference.
The study included an untreated control arm, which permits comparison with the course measured in that group, subject to the design and analysis. The record does not provide the arm-specific primary-outcome estimates or their uncertainty. It is therefore not possible to say from the posted record whether either GT005 dose had a larger or smaller mean change than control, or whether the two dose groups differed from one another.
Safety information is reported separately as counts of participants affected by serious and other adverse events, along with deaths. Those figures describe events recorded in the study groups; they do not establish that an event was caused by an intervention. The event counts should not be treated as a substitute for the missing primary-outcome comparison.
The study is listed as terminated. Termination status is a registry descriptor, not an explanation for why the study ended and not a statistical result. The reason for termination and its relationship, if any, to outcomes are not reported in the registry record. Overall, the record allows a reader to understand the trial question and some safety counts, but does not support a quantitative conclusion about the primary endpoint.
9. Statistical Methods Explained
The statistical details available in the registry record are limited. It identifies a continuous primary endpoint, a least-squares mean as the parameter, and standard error as the dispersion measure. It also describes the primary-outcome analysis population and the outcome’s measurement schedule. The model specification, covariates, handling of repeated measurements, missing-data method, and hypothesis-testing procedure are not reported in the registry record. The explanations below describe general statistical concepts and should not be read as a claim that a particular unreported method was used.
What does a least-squares mean represent?
A least-squares mean is generally a model-based estimate of a group mean. Unlike a simple arithmetic average, it can be adjusted for variables included in the model. The interpretation depends on the model, the adjustment variables, and the population to which the estimate refers. Since the registry record does not identify the model or its covariates, the precise adjustment behind the stated parameter is not reported in the registry record. The label alone does not reveal whether the estimate is adjusted for baseline GA, visit, treatment group, or other factors.
For a continuous outcome such as GA area, a mean summarizes the average measurement or change in a group. It does not show the range of individual outcomes or how many participants had a particular pattern. A comparison of means can be useful for estimating an average group difference, but interpretation also requires uncertainty and attention to the analysis population. No single primary-outcome estimate is reported for a direct comparison in the registry record.
What does the standard error tell the reader?
A standard error describes the precision of an estimated quantity, such as a mean. In general, smaller standard errors indicate estimates with less sampling uncertainty, while larger standard errors indicate greater uncertainty. A standard error is not the standard deviation of individual measurements: the standard deviation describes participant-level spread, whereas the standard error concerns uncertainty in an estimate. The record names standard error as the dispersion measure but does not give a primary-outcome estimate and its standard error for a single comparison.
A confidence interval is a range of values compatible with the data under the statistical model and its assumptions. It communicates uncertainty around an estimate and helps readers judge which effect sizes remain plausible. A confidence interval is not reported for the primary comparison in the registry record. A p-value, if reported, would address compatibility with a specified null hypothesis under a model; it would not, by itself, describe effect magnitude or clinical importance. The registry record does not report a single primary-outcome test result.
Why do repeated measurements matter?
The primary-outcome description lists baseline and several post-baseline visits through Week 72. Repeated measurements on the same participant are generally correlated: a participant’s measurements over time are not independent observations. Statistical approaches for longitudinal data can account for this correlation and use the pattern of observations across visits. Different choices about the time effect, covariance structure, and treatment-by-time comparison can lead to different estimates and uncertainty. The registry record does not specify how repeated measurements were modeled.
The outcome is also evaluated at multiple time points and appears among a broader group of outcomes and analyses. In general, testing many outcomes, visits, or group contrasts can increase the chance of a false positive if each test is treated as an independent opportunity to declare a finding. A prespecified multiplicity strategy can address that issue, for example by controlling the overall error rate or by defining a testing sequence. Which approach, if any, was used is not reported in the registry record. The registry record’s note that the primary outcome has several categories or time points and was not reduced to one comparison means there is no single primary contrast to interpret in this summary.
Why can over-dispersion matter?
Over-dispersion is a general issue for count data when observed variability exceeds what a chosen statistical model assumes. It can make standard errors too small if the extra variability is ignored. The primary endpoint in this study is a continuous measure, not a count outcome, so over-dispersion is not a description of the primary GA-area measure. It may be relevant to some kinds of event-count analyses in general, but the registry record does not provide enough detail to assess whether it applied to any analysis in this trial.
How should planning calculations be read?
The registry record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect. These are assumptions for illustration, not the trial’s own design justification and not observed power. A sample size calculated under such assumptions is a planning quantity: it describes the participants per arm that a hypothetical design would require under those assumptions. It does not establish the probability that the completed trial detected an effect, and it does not replace an estimate with uncertainty. The trial’s own sample-size justification and any associated assumptions are not reported in the registry record.
Because the primary comparison is not reported as a single estimate, the record does not support a calculation-based interpretation of its size or precision. The statistical labels describe how some quantities are characterized, but do not reveal the complete analysis plan or provide the missing primary result.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is measured at more than one post-baseline visit, and the registry record lists multiple secondary outcomes and 24 analyses. When several outcomes, visits, or contrasts are examined, the interpretation of statistical tests depends on whether and how multiplicity was handled. A prespecified plan may designate a primary comparison, adjust for multiple testing, or arrange tests in a defined sequence. Such choices affect the meaning of p-values and confidence intervals. The multiplicity strategy is not reported in the registry record.
The primary-outcome description identifies the Full Analysis Set as participants with a valid measurement and without a protocol deviation with impact. The record does not provide the number of participants included in this population or explain how protocol deviations were judged to affect the outcome. It also does not report whether all randomized participants were included in other analyses or how participants were handled if they discontinued or lacked measurements.
Missing outcome data can affect interpretation when participants with observed measurements differ from those without them. General approaches may use model assumptions, imputation, or sensitivity analyses to examine the consequences of missingness. Each approach relies on assumptions, and sensitivity analyses can show whether conclusions depend on those assumptions. The method used for missing data, the amount and pattern of missingness, and any sensitivity analyses are not reported in the registry record.
The record gives a measurement schedule through Week 72 for the primary endpoint, but a schedule does not establish that measurements were available at every visit for every participant. Without the analysis details and a single primary-outcome comparison, readers cannot assess how missing data, analysis populations, or multiplicity may have influenced the result.
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 |
|---|---|---|---|
| GT005@Medium Dose@[5E10 vg] | 22 | 87 | 25.3% |
| GT005@High Dose@[2E11 vg] | 25 | 86 | 29.1% |
| Untreated Control | 10 | 82 | 12.2% |
| Overall | 57 | 255 | 22.4% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| GT005@Medium Dose@[5E10 vg] | 4 of 87 |
| GT005@High Dose@[2E11 vg] | 1 of 86 |
| Untreated Control | 1 of 82 |
| Overall | 6 of 255 |
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 |
|---|---|
| GT005@Medium Dose@[5E10 vg] | 76 of 87 |
| GT005@High Dose@[2E11 vg] | 75 of 86 |
| Untreated Control | 50 of 82 |
| Overall | 201 of 255 |
Most frequent serious adverse event terms
| Event term | Organ system | GT005@Medium Dose@[5E10 vg] | GT005@High Dose@[2E11 vg] | Untreated Control | Overall |
|---|---|---|---|---|---|
| Atrial fibrillation | Cardiac disorders | 3 of 87 | 1 of 86 | 0 of 82 | 4 of 255 |
| Myocardial infarction | Cardiac disorders | 1 of 87 | 1 of 86 | 1 of 82 | 3 of 255 |
| Retinal detachment - Study eye | Eye disorders | 1 of 87 | 2 of 86 | 0 of 82 | 3 of 255 |
| Endophthalmitis - Study eye | Infections and infestations | 0 of 87 | 3 of 86 | 0 of 82 | 3 of 255 |
| Sepsis | Infections and infestations | 1 of 87 | 2 of 86 | 0 of 82 | 3 of 255 |
| Hip fracture | Injury, poisoning and procedural complications | 2 of 87 | 0 of 86 | 1 of 82 | 3 of 255 |
| Cerebrovascular accident | Nervous system disorders | 1 of 87 | 1 of 86 | 1 of 82 | 3 of 255 |
| Syncope | Nervous system disorders | 2 of 87 | 1 of 86 | 0 of 82 | 3 of 255 |
| Acute kidney injury | Renal and urinary disorders | 0 of 87 | 2 of 86 | 1 of 82 | 3 of 255 |
| Angina pectoris | Cardiac disorders | 1 of 87 | 0 of 86 | 1 of 82 | 2 of 255 |
Most frequent non-serious adverse event terms
| Event term | Organ system | GT005@Medium Dose@[5E10 vg] | GT005@High Dose@[2E11 vg] | Untreated Control | Overall |
|---|---|---|---|---|---|
| Cataract - Study eye | Eye disorders | 21 of 87 | 20 of 86 | 3 of 82 | 44 of 255 |
| COVID-19 | Infections and infestations | 14 of 87 | 12 of 86 | 9 of 82 | 35 of 255 |
| Retinal pigmentation - Study eye | Eye disorders | 12 of 87 | 22 of 86 | 0 of 82 | 34 of 255 |
| Conjunctival haemorrhage - Study eye | Eye disorders | 18 of 87 | 12 of 86 | 1 of 82 | 31 of 255 |
| Retinal haemorrhage - Study eye | Eye disorders | 8 of 87 | 10 of 86 | 2 of 82 | 20 of 255 |
| Cataract - Fellow eye | Eye disorders | 5 of 87 | 10 of 86 | 2 of 82 | 17 of 255 |
| Urinary tract infection | Infections and infestations | 7 of 87 | 3 of 86 | 3 of 82 | 13 of 255 |
| Intraocular pressure increased - Study eye | Investigations | 11 of 87 | 2 of 86 | 0 of 82 | 13 of 255 |
| Eye pain - Study eye | Eye disorders | 5 of 87 | 7 of 86 | 0 of 82 | 12 of 255 |
| Ocular hypertension - Study eye | Eye disorders | 6 of 87 | 6 of 86 | 0 of 82 | 12 of 255 |
Serious events with the highest arm-level rate: endophthalmitis - study eye (3.5%), atrial fibrillation (3.4%), cardiac failure congestive (2.3%), retinal detachment - study eye (2.3%), sepsis (2.3%).
The registry record reports serious adverse events and other adverse events by study group, using the number at risk and number affected. For serious adverse events, the medium-dose group had 87 at risk and 22 affected; the high-dose group had 86 at risk and 25 affected; and untreated control had 82 at risk and 10 affected. Overall, 255 were at risk and 57 were affected. These are participant counts, not counts of every individual event.
For other adverse events, 76 of 87 participants in the medium-dose group were affected, 75 of 86 in the high-dose group were affected, and 50 of 82 in untreated control were affected. Overall, 201 of 255 participants were affected. The registry record also reports 4 deaths in the medium-dose group, 1 in the high-dose group, and 1 in untreated control, with 6 overall.
These summaries do not establish whether an event was caused by GT005, the underlying condition, or another factor. They also do not show event timing, duration, severity beyond the serious-event classification, or participant-level overlap between categories. The listed serious-event terms include Endophthalmitis - Study eye at 3.5%, Atrial fibrillation at 3.4%, Cardiac failure congestive at 2.3%, Retinal detachment - Study eye at 2.3%, Sepsis at 2.3%, and Acute kidney injury at 2.3%. The record does not provide enough detail in these summaries to infer comparative risk or causation.
12. What the Result Does, and Does Not, Mean
The registry record identifies a randomized Phase II comparison of two GT005 doses with untreated control and defines a primary endpoint based on change in GA area through Week 72. It also records the study as terminated and reports participant counts for serious adverse events, other adverse events, and deaths. Those details describe the study and its posted safety summaries; they do not answer the primary efficacy question by themselves.
The record does not report a single primary-outcome comparison. There is no reported estimate of the difference in mean GA change between either GT005 group and control, nor a confidence interval that would show the precision of such a difference. Consequently, the record does not establish the direction, size, or statistical uncertainty of a primary-outcome contrast. A missing comparison cannot be interpreted as evidence that the groups were the same, or that one group did better.
Safety counts also require restraint. They indicate how many participants were recorded as affected in each group, but the counts do not identify whether an intervention caused an event. The counts do not by themselves account for differences in follow-up, timing, event duration, or the number of events experienced by an individual. The registry record does not provide a causal analysis of these events.
More generally, statistical results describe data under stated design and analysis assumptions. A group average does not describe every participant, and a statistical test alone does not establish clinical importance. To assess the primary endpoint fully, readers would need the group estimates, their uncertainty, details of the analysis, and information about missing measurements and multiplicity. Those details are not reported in the registry record in a form that yields a single primary comparison.
The study’s terminated status should not be treated as an outcome or an explanation. The reason for termination is not reported in the registry record. No conclusion about efficacy, lack of efficacy, or the reason the study ended follows from termination status alone.
13. Why This Trial Matters Statistically
HORIZON raises statistical issues that are common in trials with continuous imaging outcomes and repeated measurements. The primary endpoint tracks change in GA area from baseline through Week 72, with measurements scheduled at several visits. That structure makes the definition of the target comparison important: a comparison at a specific visit, an average across visits, or a modeled trajectory can represent different questions. The registry record specifies the endpoint and schedule but does not report a single comparison or the model used.
The study also compares two dose groups with an untreated control and includes a range of secondary outcomes. In general, multiple groups, visits, and outcomes create choices about which estimates are confirmatory and how uncertainty should be interpreted across tests. Those choices should be defined in a statistical plan. The registry record does not report the multiplicity strategy, so the role of any individual analysis cannot be fully assessed from the record.
The mismatch between the registry masking field and the official title’s description is another reporting detail relevant to interpretation. Masking can influence measurement and other trial procedures, especially when outcomes involve assessment. The record does not explain the difference between “quadruple” masking and the official title’s “open-label, outcomes-assessor masked” description, so the operational masking arrangement remains unclear.
Finally, the study record illustrates why a clear endpoint description is not a substitute for a reported estimate. It supplies the measure, time point, unit, and analysis-population description, yet does not provide one primary contrast with its precision. Without that result, readers can characterize the intended statistical question and examine posted safety counts, but cannot quantify the primary-outcome finding.
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.
Several trial-specific limitations of interpretation arise from what is and is not reported. Most importantly, the registry record does not give a single primary-outcome comparison for change in GA area at Week 72. It therefore does not allow assessment of the size or precision of a difference between either GT005 dose and untreated control. The record’s note that the primary outcome has several categories or time points and was not reduced to one comparison leaves the primary result without a single estimate to interpret.
The registry identifies a least-squares mean and standard error, but does not describe the model behind those quantities. Covariate adjustment, repeated-measures structure, assumptions, and the treatment contrasts are not reported in the registry record. The analysis population is described, but its size and the reasons for excluding measurements or participants are not given. Missing-data handling and sensitivity analyses are also not reported.
The record lists 11 outcome measures and 24 analyses, but does not provide a multiplicity plan. This makes it difficult to determine how the set of analyses was prioritized or how uncertainty should be interpreted across outcomes and visits. The registry record also does not provide the study’s sample-size justification, so the rationale for the enrollment target cannot be assessed from this information.
There is an unresolved difference between the registry’s masking classification and the official-title description. The record does not explain this discrepancy. It also lists termination status without a reason for termination. Neither point permits an inference about study conduct or outcomes, but both limit context available to readers.
The safety summaries are counts of affected participants and deaths. They do not establish causation and do not provide detailed timing or individual event histories. These are limitations of the available record, not proof that the trial did or did not collect additional information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: HORIZON: A Phase II Study to Evaluate the Safety and Efficacy of Two Doses of GT005 — NCT04566445.
- Registry record last updated 2026-01-28; status last verified 2026-01.
- Results first posted 2025-07-10.
- 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
HORIZON (NCT04566445) was a randomized, controlled Phase II parallel-group study sponsored by Gyroscope Therapeutics Limited. It enrolled 255 participants and evaluated a single subretinal injection of GT005 at medium dose [5E10 vg] or high dose [2E11 vg] against untreated control in GA secondary to dry age-related macular degeneration. The registry lists the study as terminated, with a start date of 2020-09-28 and primary completion on 2024-06-10.
The primary endpoint was change from baseline to Week 72 in GA area measured by fundus autofluorescence and expressed in mm^2. The record identifies a least-squares mean, standard error, and Full Analysis Set description, but does not report a single primary-outcome comparison. It lists secondary outcomes across imaging, visual function, reading performance, and safety. Serious adverse events, other adverse events, and deaths are reported as participant counts by group. The reason for termination, detailed statistical plan, missing-data methods, and multiplicity strategy are not reported in the registry record.