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VANCOUVER -- More frequent anti-VEGF treatment correlated with greater improvement in visual acuity for patients with neovascular age-related macular degeneration (AMD), a large retrospective study suggested.

Patients who received at least seven intravitreal injections during the first 12 months of treatment had significantly greater improvement in visual acuity, with an average ETDRS letter gain of 6.4 versus 2.1 for patients who received no more than six injections during the first year. Patients who received at least seven injections also had a higher mean visual acuity score at 12 months.

"Consistent with results of clinical trials, in routine clinical practice, maintenance of visual gains was associated with more frequent anti-VEGF injections in patients with neovascular AMD," Andrew Moshfeghi, MD, of the University of Southern California in Los Angeles, reported here at the meeting. "Patients with neovascular AMD were more likely to receive more frequent injections during the first year of treatment. Annually, a trend towards more injections during the first year of treatment was observed."

Clinical trials of anti-VEGF therapy have evaluated multiple dosing schedules, including monthly, bimonthly, quarterly, as-needed, and strategies to extend treatment intervals over time (treat-and-extend). During the conduct of clinical trials, adherence to assigned dosing intervals "relaxed" over time, which was associated with declines in visual acuity, said Moshfeghi. Conversely, improvements in visual acuity were maintained in patients who adhered more closely to the assigned treatment interval.

Authors of a of clinical trials with anti-VEGF treatment and follow-up of at least 3 years concluded that consistent dosing to maintain a fluid-free state is the key to maintaining vision improvement in patients with neovascular AMD.

"If you change your mind and start to get more frequent dosing, you can't really catch up to where you left off," said Moshfeghi.

The extent to which clinical practice mimicked clinical trials remained unclear, with respect to treatment injection intervals. To examine the issue, Moshfeghi and colleagues analyzed patient records from the Vestrum Health Retina Research Dataset, which comprises multiple ophthalmology practices.

The analysis included patients with newly diagnosed neovascular AMD treated with anti-VEGF therapy for at least 1 year. Investigators separated patients into two groups: Patients who received six or fewer injections during the first 12 months of treatment and those who received seven or more injections. Visual acuity measurements were converted into approximated ETDRS letter scores.

A review of baseline characteristics showed that 1,840 (23%) patients received six or fewer injections (mean of 4.5) and 6,287 (77%) received at least seven injections during the first 12 months of treatment (mean of 9.1). The baseline mean visual acuity was 61 letters for the patients who received fewer injections and 66 letters for those who received more frequent treatment.

At baseline, 23% of patients who received fewer injections has visual acuity ≥20/40, 39% had <20/40 to 20/100, 13% had <20/100 to 20/200, and 24% had <20/200. Among patients who received more frequent injections, the corresponding proportions were 21%, 49%, 15%, and 15%.

Comparison of improvement in visual acuity (letter count) over 1 year showed significantly better results in the group of patients who received seven or more injections. Mean visual acuity increased rapidly in the patients who received seven or more injections, from 66 letters at baseline to 72 letters by the end of 12 weeks. The mean value reached a peak of 75 letters by the end of 24 weeks and was maintained through 12 months (P<0.001).

Mean visual acuity in the patients receiving fewer injections increased from 61 letters at baseline to 65 at the end of the 12 weeks, remained at 65 for an additional 12 weeks, and then declined to 63 letters at the end of the first year of treatment.

Analysis of patients with follow-up data to 24 months showed a visual acuity benefit for patients who received six or fewer injections during the first year. Among patients who continued to receive six or fewer injections (N=415), mean visual acuity declined from 71.4 letters at the start of year 2 to 67.5 at the end of the second year. Patients who increased treatment frequency to at least seven injections during the second year (N=188) had stable vision during the second year (mean of 75.8 letters at the beginning, 75.3 at the end).

Among patients who received seven or more treatment injections during the first 12 months, those who were treated less frequently during the second 12 months had a decline in mean visual acuity, whereas those who continued to receive at least seven injections during the second 12 months had stable vision.

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