The study enrolled 813 patients, of whom 810 received ≥ 1 IVT-AFL injection and comprised the SAS (Online Resource 2). A total of 471 of the patients who enrolled (57.9%) completed the study, defined as a study duration longer than 21 months; 772 patients (95.0%) completed 4 months, 737 (90.7%) completed 6 months, 646 (79.5%) completed 12 months, and 307 (37.8%) completed 24 months. Of the 327 patients who did not complete the study, 182 (55.7%) were lost to follow-up and 48 patients (14.7%) discontinued treatment. Of those who discontinued treatment, 9 withdrew following the patient’s decision and 39 discontinued for “other reasons” (including 10 for lack of efficacy).

The overall FAS comprised 709 patients (87.2% of enrolled patients). The FAS1Y group consisted of 342 patients (regular cohort, 140 patients; irregular cohort, 202 patients) and the FAS2Y group consisted of 233 patients (regular cohort, 37 patients; irregular cohort, 196 patients).

The baseline demographics and disease characteristics are listed in Online Resource 3 for the overall FAS and in Online Resource 4 for FAS1Y and FAS2Y according to the regularly and irregularly treated cohorts. In the overall FAS, the mean ± SD age of the patients was 77.7 ± 7.3 years (range: 52–97 years) and 60.1% were female (Online Resource 3). The mean baseline VA was 0.34 ± 0.24 decimals, and the mean baseline CRT was 382 ± 125 µm. There were no marked differences in the baseline VA and OCT findings between the FAS1Y and FAS2Y cohorts or between the regularly and irregularly treated cohorts (Online Resource 4). Some minor differences were observed between the fluorescein angiography results of regularly and irregularly treated patients, particularly for FAS2Y, in which more irregularly treated patients had predominantly classic choroidal neovascularization (CNV; 52.5% vs 35.7% in regularly treated patients) and more regularly treated patients had non-classic occult CNV (50.0% vs 29.5% in irregularly treated patients). The time between symptom onset and diagnosis of nAMD was ≤ 2 weeks in 30.0% of patients (n = 212), between 2 weeks and 1 month in another 30.0% of patients (n = 212), and > 1 month in 40.0% of patients (n = 283). Following diagnosis, the mean time to IVT-AFL treatment was 34 ± 112 days.

Over the first 12 months in the overall FAS, patients had a mean ± SD of 3.7 ± 1.9 visits for injections only, 3.1 ± 2.1 monitoring visits (without injections), and 0.9 ± 1.7 combined visits for both monitoring and injections. Between months 12 and 24, there was a mean of 2.4 ± 1.9 injection-only visits, 4.2 ± 2.4 monitoring visits, and 0.8 ± 1.6 combined visits. Thus, over the 2-year study period, there was a mean of 5.9 ± 3.2 injection-only visits, 7.0 ± 4.0 monitoring visits, and 1.7 ± 3.0 combined visits. The mean time between injections in the overall FAS was 2.4 ± 1.1 months, whereas the mean time between visits (any visit type) was 1.7 ± 0.6 months.

Patients completing 12-month follow-up (FAS1Y) received a mean of 5.6 IVT-AFL injections over 12 months, whereas patients completing 24-month follow-up (FAS2Y) received 3.1 injections between months 12 and 24, and 8.6 injections in total over the full 2-year study period (Table 1). In the FAS1Y cohort, regularly and irregularly treated patients received a mean of 7.3 and 5.0 injections within the first 12 months, respectively. In the FAS2Y cohort, regularly and irregularly treated patients received a mean of 7.6 and 5.7 injections in the first 12 months, 5.5 and 2.5 injections between months 12 and 24, and 12.2 and 7.7 injections in total over the full 2-year study period, respectively. The distribution of the number of injections over the study period is shown in Online Resource 5.

In the overall FAS, at months 12 and 24, the mean ± SD change in VA from baseline was + 0.09 ± 0.24 and + 0.02 ± 0.25 decimals, respectively (Online Resource 6). In the 572 patients (80.7%) who received 3 initial monthly doses of IVT-AFL, the mean VA increased from 0.35 ± 0.24 decimals at baseline to 0.41 ± 0.27 at month 4 and 0.42 ± 0.28 at month 6. In the 137 patients (19.3%) who did not receive 3 initial monthly injections, the mean VA increased from 0.32 ± 0.22 (baseline) to 0.37 ± 0.26 (month 4) and 0.37 ± 0.30 decimals (month 6). By month 12, there was little difference between the 2 arms (the mean change in VA from baseline to month 12 was 0.09 ± 0.25 and 0.08 ± 0.22 decimals for patients with and without the 3 initial monthly doses, respectively; note that only descriptive statistics were generated for these data).

In the FAS1Y, the mean ± SD VA at baseline was 0.38 ± 0.25 decimals in the total population, and 0.41 ± 0.25 and 0.35 ± 0.24 decimals in the regular and irregular cohorts, respectively. The mean change in VA from baseline to month 12 was + 0.09 ± 0.24 decimals (overall), + 0.11 ± 0.24 decimals (regular cohort), and + 0.07 ± 0.24 decimals (irregular cohort). The mean difference in the change in VA from baseline to month 12 between the regular and irregular cohorts was 0.04 decimals, which was not statistically significant (95% CI: − 0.01, 0.10; p = 0.0963). To further evaluate differences in visual acuity between regularly and irregularly treated patients, a repeated-measures model was used. Across year 1, the difference in trend between the regular and irregular cohorts was statistically significant (p = 0.0034), with VA higher at each time point in the regularly treated cohort; the time effect (p < 0.0001) and interaction between time and cohort (p = 0.0096) were also statistically significant (Fig. 1b).

Trend in VA from baseline. a Absolute mean VA for the overall FAS over 24 months, b least square mean VA from baseline to month 12 for the FAS1Y by regular and irregular cohort, and c least square mean VA from baseline to month 24 for the FAS2Y by regular and irregular cohort. BL, baseline; FAS, full analysis set; FAS1Y, year 1 FAS; FAS2Y, year 2 FAS; VA, visual acuity

In the FAS2Y, the mean ± SD VA at baseline was 0.41 ± 0.26 decimals in the total population, and 0.48 ± 0.28 and 0.39 ± 0.25 decimals in the regular and irregular cohorts, respectively. The mean change in VA from baseline to month 24 was + 0.02 ± 0.25 decimals (overall), + 0.05 ± 0.22 decimals (regular cohort), and + 0.02 ± 0.25 decimals (irregular cohort). The mean difference in the change in VA from baseline to month 24 between the regular and irregular cohorts was 0.03 decimals, which was not statistically significant (95% CI: − 0.06, 0.11; p = 0.5458). In a repeated-measures model, the difference in trend between the regular and irregular cohorts across year 2 was statistically significant (p = 0.0222), with VA higher at each time point in the regularly treated cohort; the time effect was also statistically significant (p < 0.0001), whereas the interaction between time and cohort was not (p = 0.1495) (Fig. 1c).

At months 12 and 24 in the overall FAS, the mean ± SD change in CRT from a baseline of 382 µm was − 107 ± 120 µm (reduced to 276 µm) and − 95 ± 118 µm (reduced to 274 µm), respectively (Fig. 2).

Mean change in CRT from baseline to month 24 for the overall FAS. CRT was not recorded for all patients for whom optical coherence tomography was performed. BL, baseline; CRT, central retinal thickness; FAS, full analysis set

In the FAS1Y, the mean CRT at baseline was 383 ± 121 µm overall, with a baseline of 380 ± 113 µm and 384 ± 127 µm in the regular and irregular cohorts, respectively. The mean change from baseline to month 12 was − 108 ± 120 µm overall; − 102 ± 109 µm for the regular cohort, and − 113 ± 129 µm for the irregular cohort. The mean difference of 12 µm (95% CI: − 16, 39) in CRT change from baseline to month 12 between regularly and irregularly treated patients was not statistically significant (p = 0.4067).

In the FAS2Y, the mean CRT at baseline was 369 ± 118 µm overall, with a baseline of 379 ± 122 and 368 ± 118 µm in the regular and irregular cohorts, respectively. The mean change from baseline to month 24 was − 94 ± 117 overall, − 85 ± 114 for the regular cohort and − 96 ± 118 for the irregular cohort. The mean differences in CRT change from baseline between the regular and irregular cohorts at month 12 (2 µm [95% CI: − 42, 46; p = 0.9283]) and month 24 (11 µm [95% CI: − 32, 55; p = 0.6061]) were not statistically significant. The OCT assessments for most patients (n = 643) were performed using spectral-domain OCT; time-domain OCT was used for 11 of the remaining patients, and the instrument used was unknown for 36 patients.

Of the 813 enrolled patients, all but 3 (n = 810, 99.6%) received ≥ 1 injection of IVT-AFL and were included in the SAS, and patients included in the SAS were treated for a mean duration of 13.7 ± 8.0 months. Overall, 9.0% (n = 73) of patients experienced TEAEs (Table 2). Ocular TEAEs were reported in 4.1% (n = 33) of patients, with the most common TEAE being cataracts (0.6%; n = 5). No cases of endophthalmitis, intraocular inflammation, or retinal vasculitis were reported. Five patients (0.6%) reported 6 serious ocular TEAEs in the study eye (n = 1 each for macular hole, retinal detachment, retinal hemorrhage, and vitreous hemorrhage; n = 2 for retinal pigment epithelial tear); although none of these events were judged by the attending clinical investigator to be related to the study drug, 3 of the events (retinal detachment, n = 1; retinal pigment epithelial tear, n = 2) were considered related to the intravitreal injection procedure, and 2 of the affected patients permanently discontinued IVT-AFL. Systemic TEAEs were reported in 44 patients (5.3%) with the most common occurring in 3 patients (femur fracture [0.4%]). Three drug-related TEAEs were reported: 2 ocular TEAEs (macular fibrosis and lack of response to treatment) and 1 non-ocular TEAE (acute myocardial infarction considered to be serious). Fifteen deaths (1.9%) were reported during the 2-year study, and none were considered to be related to IVT-AFL treatment.