They may be wonder drugs for new blood vessel growth in the posterior segment, but anti-VEGF agents have yet to prove their merit in the front of the eye. A recent trial confirms the uphill battle for an indication of this sort.
Most studies investigating the role of anti-VEGF in the corneal neovascularization process have focused on prevention, but the majority of patients are only treated when new vessels are already formed. A new study is the first to investigate subconjunctival use of aflibercept in a clinical trial setting for the regression of formed corneal neovascularization in human patients.
In a prospective clinical trial, patients with corneal pathologies complicated by corneal neovascularization who were candidates for anti-VEGF treatment at the discretion of a cornea specialist were included. A single subconjunctival injection of 0.08mL of aflibercept was administered near the limbus in proximity to the areas of maximal pathological neovascularization, with follow-up visits on days seven, 30, 60 and 90 following injection. Best corrected visual acuity (BCVA), intraocular pressure, slit lamp examination, digital cornea photography, specular microscopy and anterior-segment OCT were documented at each visit.
Six eyes of six patients were analyzed and there was no change noted in extent, density or centricity of corneal blood vessels at seven, 30 and 90 days after injection. Best-corrected visual acuity fluctuated insignificantly in five patients during follow-up time, and objective but not subjective improvement of BCVA was noted in one patient with no concurrent change of neovascularization. For that reason, the recruitment halted prematurely.
“The negative results of the preclinical study were received at the time of first recruitments to
the clinical trial. These, in conjunction with the lack of clinical improvement in the eyes of the first six recruited patients, led to the decision to stop the recruitment,” the authors explained in their paper on the study. “The clinician’s impression was that no regression in neovascularization is apparent in any of the patients, and none reported an improvement in BCVA. The eye of patient five has supposedly improved; however, this is a severely amblyopic eye and the improvement from a BCVA of 3.0 to 1.5 could stem from inaccuracy of the exam or fluctuating vision rather than frank improvement. This change is not explained by the change in neovascularization and was not noted subjectively. We therefore proceeded with image analysis before enlarging the cohort size, and earlier than originally planned.”
A similar study to assess the efficacy of ziv-aflibercept for this indication, or the combination of aflibercept with other treatment modalities may be warranted, the authors concluded.
Sella R, Ishai MB, Livny E, et al. Subconjunctival aflibercept for the treatment of formed corneal neovascularization. Eyes & Contact Lens 2021; 47: 180-184.