Maximal Extension Interval and Visual Outcomes in a Treat-and-Extend Protocol: A Post Hoc Analysis of the CANTREAT Randomized Trial
Bibliographic record
Abstract
INTRODUCTION: The Canadian Treat-and-Extend Analysis Trial with Ranibizumab (CANTREAT) was a 2-year, multicentred, randomized clinical trial to evaluate treat-and-extend (T&E) relative to monthly administration of ranibizumab in neovascular age-related macular degeneration (nAMD). This post hoc analysis of the CANTREAT trial explores the relationship between the maximal extension interval tolerated by patients receiving T&E ranibizumab and visual acuity outcomes. METHODS: Treatment-naïve patients with nAMD were randomized to receive either a once-monthly dosing or T&E regimen of ranibizumab across 27 treatment centres in Canada and were followed for 24 months. For this post hoc analysis, patients in the T&E cohort were subdivided into the following groups based on maximum extension interval: 4 weeks, 6 weeks, 8 weeks, 10 weeks, and 12 weeks. The primary outcome was the change in ETDRS best-corrected visual acuity (BCVA) from baseline to month 24 while secondary outcomes included change in central retinal thickness (CRT). All results were reported using descriptive statistics. RESULTS: A total of 285 participants undergoing T&E were enrolled in this post hoc analysis. At month 24, the change in BCVA from baseline was +8.5 ± 9.3, +7.7 ± 13.8, +4.4 ± 9.6, +4.4 ± 18.5, and +7.8 ± 14.8 letters in the 4-, 6-, 8-, 10-, and 12-week cohorts, respectively. The change in CRT at month 24 was -79.2 ± 95.0, -143.9 ± 128.9, -97.7 ± 101.1, -120.9 ± 105.3, and -133.2 ± 108.8 μm in the 4-, 6-, 8-, 10-, and 12-week cohorts, respectively. CONCLUSION: The capacity to extend does not necessarily associate with improved visual acuity outcomes, with the poorest change in BCVA seen in those extended 8-10 weeks. The highest change in BCVA and lowest decrease in CRT was in the group maximally extended for 4 weeks. There was a correlation between change in BCVA and change in CRT for other extension groups. Future studies should establish the predictive factors for successful extension in patients undergoing T&E in nAMD.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Observational | low |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Randomized trial | medium |
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.023 | 0.025 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.005 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.014 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedLabeled directly by 2 models reading the full record.
The models disagree on parts of this classification; every voice is preserved in the section at the end of the page.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".