Purpose: Fibrovascular scar formation related to subfoveal type 2 choroidal neovascularization (CNV) often causes severe vision loss in eyes with age-related macular degeneration. The authors assessed additional impacts of intravitreal tissue plasminogen activator (tPA), a fibrinolytic compound, combined with intravitreal ranibizumab (IVR) on subfoveal type 2 CNV.
Methods: Eight eyes of eight patients with type 2 CNV underwent intravitreal injections of ranibizumab and tPA (IVR/tPA) (40 kIU). Twelve eyes of 12 patients with type 2 CNV were treated with only IVR injections, as the control group. For retreatment, IVR was performed as needed. The best-corrected visual acuity (BCVA) and the central retinal thickness (CRT) and macular volume (MV) on optical coherence tomography were recorded periodically for 6 months.
Results: The subretinal fibrinous and fibrovascular tissue complex regressed or contracted immediately after administration of IVR/tPA in contrast to IVR monotherapy. The total numbers of IVR injections did not differ significantly between the two groups. The mean logarithm of the minimum angle of resolution BCVA in the combination therapy group improved significantly from 0.72 at baseline to 0.51 at month 6 and was superior to that in the monotherapy group (0.70-0.79). The improvements of the mean CRT and MV in the combination therapy group were superior to the monotherapy group. No tPA-related complications developed.
Conclusions: tPA may have a specific ability to regress already formed subretinal fibrinous and fibrovascular tissue complexes in eyes with type 2 CNV, potentially increasing the chances of visual improvement through a synergistic relationship with anti-VEGF therapies.
Keywords: Age-related macular degeneration; Intravitreal ranibizumab; Tissue plasminogen activator; Type 2 choroidal neovascularization.