GOOD VISUAL OUTCOME AT 1 YEAR IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION WITH PIGMENT EPITHELIUM DETACHMENT: Factors Influencing the Treatment Response

Texture-Based Radiomic SD-OCT Features Associated With Response to Anti-VEGF Therapy in a Phase III Neovascular AMD Clinical Trial

Purpose

The goal of this study was to evaluate the role of texture-based baseline radiomic features (Fr) and dynamic radiomics alterations (delta, FΔr) within multiple targeted compartments on optical coherence tomography (OCT) scans to predict response to anti-vascular endothelial growth factor (VEGF) therapy in neovascular age-related macular degeneration (nAMD).

Methods

HAWK is a phase 3 clinical trial data set of active nAMD patients (N = 1082) comparing brolucizumab and aflibercept. This analysis included patients receiving 6 mg brolucizumab or 2 mg aflibercept and categorized as complete responders (n = 280) and incomplete responders (n = 239) based on whether or not the eyes achieved/maintained fluid resolution on OCT. A total of 481 Fr were extracted from each of the fluid, subretinal hyperreflective material (SHRM), retinal tissue, and sub-retinal pigment epithelium (RPE) compartments. Most discriminating eight baseline features, selected by the minimum redundancy, maximum relevance feature selection, were evaluated using a quadratic discriminant analysis (QDA) classifier on the training set (Str, n = 363) to differentiate between the two patient groups. Classifier performance was subsequently validated on independent test set (St, n = 156).

Results

In total, 519 participants were included in this analysis from the HAWK phase 3 study. There were 280 complete responders and 219 incomplete responders. Compartmental analysis of radiomics featured identified the sub-RPE and SHRM compartments as the most distinguishing between the two response groups. The QDA classifier yielded areas under the curve of 0.78, 0.79, and 0.84, respectively, using Fr, FΔr, and combined Fr, FΔr, and Fc on St.

Conclusions

Utilizing compartmental static and dynamic radiomics features, unique differences were identified between eyes that respond differently to anti-VEGF therapy in a large phase 3 trial that may provide important predictive value.

Translational Relevance

Imaging biomarkers, such as radiomics features identified in this analysis, for predicting treatment response are needed to enhanced precision medicine in the management of nAMD.

OCT-Derived Radiomic Features Predict Anti-VEGF Response and Durability in Neovascular Age-Related Macular Degeneration

PURPOSE

No established biomarkers currently exist for therapeutic efficacy and durability of anti-VEGF therapy in neovascular age-related macular degeneration (nAMD). This study evaluated radiomic-based quantitative OCT biomarkers that may be predictive of anti-VEGF treatment response and durability.

DESIGN

Assessment of baseline biomarkers using machine learning (ML) classifiers to predict tolerance to anti-VEGF therapy.

PARTICIPANTS

Eighty-one participants with treatment-naïve nAMD from the OSPREY study, including 15 super responders (patients who achieved and maintained retinal fluid resolution) and 66 non-super responders (patients who did not achieve or maintain retinal fluid resolution).

METHODS

A total of 962 texture-based radiomic features were extracted from fluid, subretinal hyperreflective material (SHRM), and different retinal tissue compartments of OCT scans. The top 8 features, chosen by the minimum redundancy maximum relevance feature selection method, were evaluated using 4 ML classifiers in a cross-validated approach to distinguish between the 2 patient groups. Longitudinal assessment of changes in different texture-based radiomic descriptors (delta-texture features) between baseline and month 3 also was performed to evaluate their association with treatment response. Additionally, 8 baseline clinical parameters and a combination of baseline OCT, delta-texture features, and the clinical parameters were evaluated in a cross-validated approach in terms of association with therapeutic response.

MAIN OUTCOME MEASURES

The cross-validated area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity were calculated to validate the classifier performance.

RESULTS

The cross-validated AUC by the quadratic discriminant analysis classifier was 0.75 ± 0.09 using texture-based baseline OCT features. The delta-texture features within different OCT compartments between baseline and month 3 yielded an AUC of 0.78 ± 0.08. The baseline clinical parameters sub-retinal pigment epithelium volume and intraretinal fluid volume yielded an AUC of 0.62 ± 0.07. When all the baseline, delta, and clinical features were combined, a statistically significant improvement in the classifier performance (AUC, 0.81 ± 0.07) was obtained.

CONCLUSIONS

Radiomic-based quantitative assessment of OCT images was shown to distinguish between super responders and non-super responders to anti-VEGF therapy in nAMD. The baseline fluid and SHRM delta-texture features were found to be most discriminating across groups.

The Association of Fluid Volatility With Subretinal Hyperreflective Material and Ellipsoid Zone Integrity in Neovascular AMD

Purpose

To evaluate the association of fluid volatility with ellipsoid zone (EZ) integrity and subretinal hyperreflective material (SHRM) volume during anti–vascular endothelial growth factor (VEGF) therapy in neovascular age-related macular degeneration (nAMD).

Methods

This study was a post hoc analysis of the OSPREY study. Retinal volatility was quantified as the standard deviation across weeks 12 to 56 for six optical coherence tomography (OCT) metrics: central subfield thickness (CST), total fluid (TF) volume, subretinal fluid (SRF) volume, intraretinal fluid (IRF) volume, macular total retinal fluid index (TRFI), and central macular TRFI. Eyes with volatility ≤ 25th or ≥ 75th percentile values were compared.

Results

Eyes with low volatility in several exudative metrics showed greater change from baseline in SHRM volume at week 12 than eyes with high volatility. During the maintenance phase (weeks 12–56), eyes exhibiting high SRF volatility demonstrated increased SHRM volume compared to eyes with low SRF volatility (P = 0.027). Eyes exhibiting high volatility in CST, TF, and SRF demonstrated less improvement in EZ total attenuation (P < 0.001, P = 0.033, and P = 0.043, respectively) than eyes with low volatility. Early exudative instability (i.e., between weeks 4–8 or weeks 8–12) in multiple parameters (i.e., CST, TF, IRF, macular TRFI, or central macular TRFI) was associated with greater volatility during the maintenance phase (P < 0.05).

Conclusions

Greater volatility in exudative OCT metrics, particularly SRF volatility, was associated with a greater increase in SHRM and less improvement in EZ integrity, suggesting that volatility is detrimental to multiple anatomic features in nAMD. Early exudative instability during the loading phase of treatment was associated with longer-term volatility in exudation.

Efficacy Outcomes of Brolucizumab Versus Aflibercept in Neovascular Age-Related Macular Degeneration Patients with Early Residual Fluid

OBJECTIVE

To compare the outcomes of brolucizumab versus aflibercept in patients with neovascular age-related macular degeneration with early residual fluid in the HAWK and HARRIER studies.

DESIGN

Post hoc analysis using pooled data from the phase 3 studies HAWK (NCT02307682) and HARRIER (NCT02434328).

PARTICIPANTS

The early residual fluid cohort for this post hoc analysis consisted of patients treated with either brolucizumab 6 mg (n = 730 patients) or aflibercept 2 mg (n = 729 patients) and who had the presence of intraretinal fluid (IRF), subretinal fluid (SRF), or both verified by spectral-domain OCT at the week 12 clinic visit.

METHODS

After 3 initial monthly doses, patients treated with brolucizumab received injections every 12 weeks (q12w) or every 8 weeks (q8w), depending on the neovascular age-related macular degeneration disease activity, whereas patients treated with aflibercept received fixed q8w dosing.

MAIN OUTCOME MEASURES

The mean change in best-corrected visual acuity and central subfield thickness (CST) from the baseline to that at weeks 48 and 96, the proportion of patients treated with brolucizumab remaining on q12w dosing to week 96, and the change in fluid status at weeks 48 and 96.

RESULTS

All analyses were based on 149 of 730 (20.4%) patients treated with brolucizumab and 217 of 729 (29.8%) patients treated with aflibercept with spectral-domain OCT-verified IRF, SRF, or both at their week 12 visit. The best-corrected visual acuity improvements from baseline at weeks 48 and 96 were numerically better for brolucizumab than for aflibercept (least square mean [standard error] 7.9 ± 1.1 vs. 4.6 ± 0.9 and 7.4 ± 1.3 vs. 2.9 ± 1.1 letters, respectively). The CST reductions from baseline at weeks 48 and 96 were consistently greater with brolucizumab than with aflibercept (least square mean [standard error], μm: -194.9 ± 13.7 vs. -123.9 ± 11.3; and -201.1 ± 14.5 vs. -134.2 ± 12.0, respectively). At weeks 48 and 96, patients treated with brolucizumab had a 40.4% and 31.3% probability of remaining on q12w dosing intervals, respectively. Fewer patients treated with brolucizumab had remaining IRF, SRF, or both at weeks 48 and 96 than patients treated with aflibercept (59.1% vs. 75.1% and 49.0% vs. 60.4%, respectively).

CONCLUSIONS

In patients with early residual fluid, defined as spectral-domain OCT-verified IRF, SRF, or both at the week 12 clinic visit, brolucizumab resolved the early residual fluid and reduced CST more effectively than aflibercept, resulting in greater best-corrected visual acuity improvements through week 96 of anti-VEGF treatment.

IMPACT OF FLUID COMPARTMENTS ON FUNCTIONAL OUTCOMES FOR PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Systematic Literature Review

PURPOSE

Understanding the impact of fluid in different retinal compartments is critical to developing treatment paradigms that optimize visual acuity and reduce treatment burden in neovascular age-related macular degeneration. This systematic review aimed to determine the impact of persistent/new subretinal fluid, intraretinal fluid, and subretinal pigment epithelial fluid on visual acuity over 1 year of treatment.

METHODS

Publication eligibility and data extraction were conducted according to Cochrane methods: 27 of the 1,797 screened records were eligible.

RESULTS

Intraretinal fluid negatively affected visual acuity at baseline and throughout treatment, with foveal intraretinal fluid associated with lower visual acuity than extrafoveal intraretinal fluid. Some studies found that subretinal fluid (particularly subfoveal) was associated with higher visual acuity at Year 1 and longer term, and others suggested subretinal fluid did not affect visual acuity at Years 1 and 2. Data on the effects of subretinal pigment epithelial fluid were scarce, and consensus was not reached. Few studies reported numbers of injections associated with fluid status.

CONCLUSION

To optimally manage neovascular age-related macular degeneration, clinicians should understand the impact of fluid compartments on visual acuity. After initial treatment, antivascular endothelial growth factor regimens that tolerate stable subretinal fluid (if visual acuity is stable/improved) but not intraretinal fluid may enable patients to achieve their best possible visual acuity. Confirmatory studies are required to validate these findings.

Managing Neovascular Age-Related Macular Degeneration in Clinical Practice: Systematic Review, Meta-Analysis, and Meta-Regression

The use of anti-vascular endothelial growth factor (VEGF) agents has profoundly changed the prognosis of neovascular age-related macular degeneration (nAMD). As clinical experiences have accumulated, it has become mandatory to summarize data to give information that can be useful in everyday practice. We conducted a systematic review to identify randomized controlled trials (RCTs) and observational studies that reported 12-month changes in best-corrected visual acuity (BCVA) in patients with nAMD on anti-VEGF monotherapy. Data were analyzed in a random-effects meta-analysis with BCVA change as the primary outcome. Meta-regression was conducted to evaluate the impact of multiple covariates. Four hundred and twelve heterogeneous study populations (109,666 eyes) were included. Anti-VEGFs induced an overall improvement of +5.37 ETDRS letters at 12 months. Meta-regression showed that mean BCVA change was statistically greater for RCTs (p = 0.0032) in comparison with observational studies. Populations following a proactive regimen had better outcomes than those following a reactive treatment regimen. Mean BCVA change was greater in younger populations, with lower baseline BCVA and treated with a higher number of injections (p < 0.001). Our results confirm that anti-VEGFs may produce a significant functional improvement at 12 months in patients with nAMD.

EFFECT OF RANIBIZUMAB AND AFLIBERCEPT ON RETINAL PIGMENT EPITHELIAL DETACHEMENT, SUBRETINAL AND INTRARETINAL FLUID IN AGE-RELATED MACULAR DEGENERATION

PURPOSE

The aim of the study was to compare the effect of three initial doses of the anti-VEGF ranibizumab and aflibercept medication on serous pigment epithelial detachment (PED), subretinal fluid (SRF) and intraretinal fluid (IRF) in the macula of treatment naive neovascular AMD (nvAMD) patients.

MATERIAL AND METHODS

The cohort consists of 148 patients, of which 74 patients were treated with ranibizumab (51 females and 23 males) and 74 with aflibercept (46 females and 28 males). The data was recorded prospectively from the moment of diagnosis and start of treatment for a period of 3 months. At the moment of diagnosis and 3 months later, an OCT examination (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany) was performed. The OCT examination included a macular scan with 25 scans. Using the OCT instrument software, we measured the maximum anterior-posterior elevation of serous PED, the highest thickness of SRF and the largest diameter of the intraretinal cystic space. The statistical significance of differences between groups was evaluated using the t-test for continuous data and the Fisher exact test for categorical data. Changes in values of continuous variables over time were evaluated using the Wilcoxon paired test. Paired comparisons of binary parameters were determined by the McNemar test.

RESULTS

Full regression of PED, SRF and IRF occurred in 3 (4.1%), 25 (39%) and 20 (51%) patients treated with ranibizumab, and in 5 (7.9%, p = 0.470), 28 (47%, p = 0.470) and 25 (57%, p = 0.827) patients treated with aflibercept, respectively. The average regression of PED, SRF and IRF was -60.4 &#956;m (median -37.5 &#956;m), -84.3 &#956;m (median -85 &#956;m) and -109.3 &#956;m (median -81 &#956;m) in patients treated with ranibizumab, and -46.3 &#956;m (median -30 &#956;m, p = 0.389), -127.7 &#956;m (median -104 &#956;m, p = 0.096) and -204.4 &#956;m (median -163 &#956;m, p = 0.005) in patients treated with aflibercept, respectively. We did not show a statistically significant difference in the regression rates of PED, SRF and IRF between the ranibizumab and aflibercept groups. (in patients with IRF after adjustment of the higher baseline IRF volumes in patients treated with aflibercept, p = 0.891).

CONCLUSION

We are convinced that ranibizumab and aflibercept have the same effect on serous PED, SRF and IRF in the macula in patients with treatment naive nvAMD during the initial loading phase.

Predominantly Persistent Subretinal Fluid in the Comparison of Age-Related Macular Degeneration Treatments Trials

OBJECTIVE

To describe predominantly persistent subretinal fluid (SRF) in eyes receiving ranibizumab or bevacizumab for neovascular age-related macular degeneration and to compare visual acuity (VA) to eyes with nonpersistent SRF.

DESIGN

Cohort within randomized clinical trial.

PARTICIPANTS

Comparison of Age-related Macular Degeneration Treatments Trials patients assigned to pro re nata treatment.

METHODS

Graders evaluated monthly OCT scans for SRF. Predominantly persistent SRF through week 12 was defined as SRF at baseline and weeks 4, 8, and 12. Predominantly persistent SRF through 1 or 2 years was defined as SRF in 80% or more of visits by years 1 or 2, respectively. Linear regression models including baseline predictors of VA and predominantly persistent intraretinal fluid (IRF) were used to evaluate mean differences in vision outcomes.

PRIMARY OUTCOME MEASURES

Predominantly persistent SRF through year 1, adjusted VA score and VA change, and foveal SRF thickness.

RESULTS

Among 406 eyes with baseline SRF, SRF persisted in 108 eyes (26.6%) through week 12, in 94 eyes (23.2%) through year 1, and in 77 eyes (19.0%) through year 2. Adjusted VA means at year 1 were similar between eyes with predominantly persistent versus non persistent SRF by week 12 (68.1 vs. 70.2 letters; P = 0.18), year 1 (67.6 vs. 70.2 letters; P = 0.11), and year 2 (71.4 vs. 70.9 letters; P = 0.78). Adjusted changes in mean VA at year 1 were similar between eyes with predominantly persistent versus nonpersistent SRF by week 12 (6.3 vs. 7.6 letters; P = 0.38), year 1 (5.5 vs. 7.8 letters; P = 0.14), and year 2 (8.1 vs. 7.7 letters; P = 0.78). Among eyes with predominantly persistent SRF through year 1, foveal SRF was absent in 46 eyes (48.9%), thickness was 1 to 200 μm in 48 eyes (50.0%) and more than 200 μm in 1 eye (1.1%) at year 1.

CONCLUSIONS

Eyes with predominantly persistent and nonpersistent SRF through week 12, year 1, or year 2 showed similar VA outcomes after adjustment for baseline covariates and persistent IRF. At the foveal center, predominantly persistent SRF was most commonly absent or present in small quantities.

Nonexudative morphologic changes of neovascularization on optical coherence tomography angiography as predictive factors for exudative recurrence in age-related macular degeneration

PURPOSE

To evaluate morphologic changes of choroidal neovascularization (CNV) on optical coherence tomography angiography (OCTA) during the nonexudative period and to correlate the features and timing of recurrence in neovascular age-related macular degeneration. (AMD).

METHODS

Two hundred thirty-eight eyes with type 1 CNV were retrospectively reviewed. For cases with exudative recurrence, OCTA images were tracked for analysis between the recurrences. Qualitative parameters of morphologic changes of CNV on OCTA, including tiny branching vessels, anastomotic loops, peripheral vascular arcade, and perilesional halo, were correlated with the features of exudative recurrence.

RESULTS

Exudative recurrence was identified in 163 cases, and among them, nonexudative morphological changes in CNV were identified using OCTA in 45 cases. For the cases with nonexudative changes on OCTA, exudative recurrence eventually developed within 0.5-3.5 months (mean, 2.3 ± 2.0 months) after identifying morphologic changes OCTA. The following changes in CNV were revealed on OCTA: tiny branching vessels in 53.3% (24/45) of cases, anastomotic loops in 40.0% (18/45), peripheral vascular arcades in 44.4% (20/45), and perilesional halo in 35.6% (16/45). Among the morphologic parameters, development of tiny branching vessels was significantly associated with early exudative recurrence (1.5 ± 1.2 months, p = 0.019), higher incidence of intraretinal fluid (IRF) (p = 0.016), and subretinal or subretinal pigment epithelial hemorrhage (p = 0.023) at recurrence, compared with other morphologic changes.

CONCLUSION

Development of tiny branching vessels of CNV on OCTA during the nonexudative period was associated with early exudative recurrence, including IRF or hemorrhage. Identifying the nonexudative changes of CNV on OCTA might predict exudative recurrence and provide additional parameters for monitoring neovascular AMD.

Three-year outcome of aflibercept treatment for Japanese patients with neovascular age-related macular degeneration

Background

To evaluate the three-year outcome after intravitreal aflibercept injection (IAI) for neovascular age-related macular degeneration (nAMD).

Methods

Forty-nine treatment-naïve nAMD patients (50 eyes) were enrolled in this prospective study. The eyes received IAI at two-month intervals in the first year. The treatment regimen was changed to IAI based on a treat-and-extend approach in the second and third years.

Results

Twenty-nine eyes of 28 patients were successfully followed up over 36 months. The nAMD subtypes included 15 eyes with typical AMD and 14 eyes with polypoidal choroidal vasculopathy. The number of IAIs performed over the 3 years was 17.2 ± 3.1 (mean ± standard deviation). The mean logMAR, which was 0.42 at baseline, improved to 0.19 (P = 0.001) at 12 months, and 0.26 (P = 0.049) at 36 months. The central retinal thickness (CRT) was 329 ± 120 μm at baseline, 151 ± 38 μm (P < 0.001) at 12 months, and 143 ± 61 μm (P < 0.001) at 36 months. The mean subfoveal choroidal thickness (SFCT) was 288 ± 97 μm at baseline, 243 ± 82 μm (P < 0.001) at 12 months, and 208 ± 63 μm (P < 0.01) at 36 months. The changes in logMAR, CRT, and SFCT over the study period did not differ between typical AMD and PCV.

Conclusion

Long-term aflibercept injection can achieve visual improvement and reduce the thickness of the retina and choroid in nAMD. Morphological improvement of these tissues may not be sufficient to sustain earlier visual improvement over the long-term.

Influence of pigment epithelial detachment on visual acuity in neovascular age-related macular degeneration

Pigment epithelial detachment (PED), the anatomical separation of the retinal pigment epithelium from the Bruch membrane, is common in many chorioretinal diseases, including neovascular age-related macular degeneration. PED is present in about 30% to 80% of neovascular age-related macular degeneration patients based on the CATT, EXCITE, and VIEW studies. The influence of PED on visual acuity is controversial as a result of inconsistent results reported by various studies. With advances in imaging technologies, it is possible to evaluate not only the presence or absence of PED, but also detailed quantitative parameters, such as height, width, greatest linear diameter, area, volume, and reflectivity within the PED. We performed a comprehensive literature review to evaluate the relationship of PED with visual acuity. In summary, the presence or persistence of a PED may still be compatible with relatively good visual acuity. There is no strong evidence that the presence of a PED or aspects of its morphology has a significant impact on visual acuity. The presence of a PED may be predictive of the need for more regular treatment. More well-designed studies with standardized PED definitions and classifications are needed to evaluate the relationship between PED and visual acuity.

Tolerating Subretinal Fluid in Neovascular Age-Related Macular Degeneration Treated with Ranibizumab Using a Treat-and-Extend Regimen: FLUID Study 24-Month Results

PURPOSE

To test the hypothesis that tolerating some subretinal fluid (SRF) in patients with neovascular age-related macular degeneration (nAMD) treated with ranibizumab using a treat-and-extend (T&E) regimen can achieve similar visual acuity (VA) outcomes as treatment aimed at resolving all SRF.

DESIGN

Multicenter, randomized, 24-month, phase 4, single-masked, noninferiority clinical trial.

PARTICIPANTS

Participants with treatment-naïve active subfoveal choroidal neovascularization (CNV).

METHODS

Participants were randomized to receive ranibizumab 0.5 mg monthly until either complete resolution of SRF and intraretinal fluid (IRF; intensive arm: SRF intolerant) or resolution of all IRF only (relaxed arm: SRF tolerant except for SRF >200 μm at the foveal center) before extending treatment intervals. A 5-letter noninferiority margin was applied to the primary outcome.

MAIN OUTCOME MEASURES

Mean change in best-corrected VA (BCVA), and central subfield thickness and number of injections from baseline to month 24.

RESULTS

Of the 349 participants randomized (intensive arm, n = 174; relaxed arm, n = 175), 279 (79.9%) completed the month 24. The mean change in BCVA from baseline to month 24 was 3.0 letters (standard deviation, 16.3 letters) in the intensive group and 2.6 letters (standard deviation, 16.3 letters) in the relaxed group, demonstrating noninferiority of the relaxed compared with the intensive treatment (P = 0.99). Similar proportions of both groups achieved 20/40 or better VA (53.5% and 56.6%, respectively; P = 0.92) and 20/200 or worse VA (8.7% and 8.1%, respectively; P = 0.52). Participants in the relaxed group received fewer ranibizumab injections over 24 months (mean, 15.8 [standard deviation, 5.9]) than those in the intensive group (mean, 17 [standard deviation, 6.5]; P = 0.001). Significantly more participants in the intensive group never extended beyond 4-week treatment intervals (13.5%) than in the relaxed group (2.8%; P = 0.003), and significantly more participants in the relaxed group extended to and maintained 12-week treatment intervals (29.6%) than the intensive group (15.0%; P = 0.005).

CONCLUSIONS

Patients treated with a ranibizumab T&E protocol who tolerated some SRF achieved VA that is comparable, with fewer injections, with that achieved when treatment aimed to resolve all SRF completely.

Ranibizumab treatment history as predictor of the switch-response to aflibercept: evidence for drug tolerance

Purpose

To investigate whether tolerance to the anti-VEGF drug, ranibizumab, develops after drug exposure and to determine whether the history of treatment with ranibizumab prior to refractoriness can predict the post-switching responses to aflibercept.

Methods

We retrospectively investigated neovascular age-related macular degeneration patients refractory to ranibizumab (intra- or subretinal fluid despite monthly injections for ≥6 months) who were switched to aflibercept and were followed up for at least 12 months on each of ranibizumab and aflibercept. Baseline characteristics and ranibizumab and aflibercept treatment history (number of injections during the first year and central retinal thickness [CRT]) were analyzed by univariate and multivariate correlation analyses.

Results

Ninety-eight eyes (88 patients, 70% females, mean age 77.5 years), including a high proportion of eyes with pigment epithelium detachment (63%), were treated with a mean of 26.2 injections during 36.8 months before switching to aflibercept. The number of ranibizumab injections required in the first year (p=0.0002) and the presence of pigment epithelium detachment (p=0.025) predicted the number of post-switching aflibercept injections required. The post-switching CRT change was predicted by the CRT increase from Month 3 to the switch time point (p<0.0001). Moreover, the CRT change correlated with the visual acuity benefit post-switching (p=0.038 and p=0.004, at 3 and 12 months post-switching, respectively).

Conclusion

Ranibizumab treatment history before switching to aflibercept correlates with the post-switching response in terms of the number of drug injections needed and CRT. Thus, drug tolerance does indeed exist and this might help to identify switching candidates.