Conbercept more patient-friendly than existing treatments for AMD
A conbercept dosing regimen of three initial monthly intravitreal injections followed by quarterly treatments appears to be effective in the treatment of neovascular age-related macular degeneration (AMD), yielding visual and anatomic benefits at 3 and 12 months, according to data from the PHOENIX trial.
“Because other antivascular endothelial growth factor (anti-VEGF) agents cannot support this dosing regimen, treatment using conbercept has the potential to be a more patient-friendly treatment than are existing treatments,” the investigators said.
The multicentre phase III trial randomized 124 patients with choroidal neovascularization (CNV) secondary to AMD to the conbercept group (n=81; mean age 66.9 years; 64.2 percent male) or the sham control group (n=43; mean age 64.6 years; 74.4 percent male).
The conbercept group received intravitreal injections at 0.5 mg once monthly for the first 3 months, then once quarterly until month 12, while the sham group received first 3 monthly sham injections and then 3 monthly injections of conbercept (0.5 mg) followed by quarterly administrations until month 12.
Conbercept produced a significant and rapid improvement in the primary endpoint of best-corrected visual acuity (BCVA) at month 3 compared with sham (mean change, 9.20 vs 2.02 ETDRS letters; p<0.001). At 12 months however, the mean changes from baseline in BCVA score did not significantly differ between (9.98 vs 8.81 ETDRS letters; p=0.64). [Am J Ophthalmol 2018;doi:10.1016/j.ajo.2018.08.026]
“Obvious visual improvements from baseline were noted in both groups, suggesting the effectiveness of the injections throughout the treatment period,” according to the investigators. “The visual acuity and central retinal thickness at 12 months showed no statistically significant differences between the conbercept and sham groups, probably because the two groups had already received the three monthly injections, which were intended to improve the impaired visual function.”
Therefore, the difference at 3 months between the two treatment groups clearly demonstrated the efficacy of conbercept treatment, they added. “The following quarterly injections were mostly intended as maintenance treatment to prevent the VA from decreasing. In other words, the stabilization of VA after the first three loading injections is a good sign.”
The drug was well tolerated, with no reports of systemic adverse events (AEs) or serious AEs. The most common ocular AEs were related intravitreal injections, such as conjunctival haemorrhage and increased intraocular pressure.
In previous studies (PIER, EXCITE, and VIEW 1 and 2), a quarterly maintenance dosing schedule of other anti-VEGF medications failed to achieve satisfactory efficacy, the investigators pointed out. This highlights the results of PHOENIX trial that conbercept is an effective and well-tolerated treatment for AMD, with the potential to provide health outcome advantages over other drugs of similar class. [Am J Ophthalmol 2008;145:239-248; Ophthalmology 2011;118:831-839; Ophthalmology 2012;119:2537-2548]
“While head-to-head studies are still needed, the PHOENIX study shows that since anti-VEGF treatment plays an increasingly important role in treating neovascular ocular diseases, decreasing the treatment frequency and compliance burden would yield considerable social benefits and probably make a difference in promoting vision healthcare,” they said.