While data from clinical trials of VEGF antagonists have demonstrated the effectiveness of these therapies for the treatment of wet AMD, “real-world” data on the long-term effects of treatment are lacking. Several studies at ARVO evaluated the effectives of aflibercept after 3 years of treatment. These studies demonstrated the long-term effectiveness of aflibercept in the treatment of wet AMD after 3 years of treatment (Babalola et al. ARVO E-Abstract 423). However, visual acuity was lower for subjects that did not complete 3 years of treatment (Vig et al. ARVO E-Abstract 411) and longer treatment was need for subjects with persistent disease activity (Eleftheriadou et al. ARVO E-Abstract 874).
A study by Queguiner et al. (ARVO E-Abstract 414) demonstrated that ranibizumab injections were effective for up to 5 years of treatment, raising the question of whether ranibizumab is a more effective treatment than aflibercept for wet AMD.
Interestingly, Gillies et al. (ARVO E-Abstract 896) did a 12-month, head-to-head comparison, looking at visual acuity changes in 394 eyes with wet AMD. There were no significant differences in visual acuity between patients treated with ranibizumab compared with aflibercept for 12 months, suggesting both drugs are effective for wet AMD in real-world clinical practice.
New delivery mechanisms
As current therapies for wet AMD require repeated intravitreal injections of anti-VEGF, numerous presentations at this year’s ARVO focused on new delivery mechanisms—many of which focused on extended-release formulations that would not only reduce patient burden, but also potentially provide improved clinical outcomes.
Owens et al. (ARVO E-Abstract 409) from Envisia Therapeutics demonstrated a proof-of-concept, multi-month release of anti-VEGF from a biodegradable hydrogel matrix (aflibercept) in vitro that was further supported by 3-month release data in non-human primates.
A bio-absorbable hydrogel depot delivery system was also described in a presentation by researchers (Jarett et al. ARVO E-Abstract 1956) from Ocular Therapeutics, but in this case, the device was used to deliver a tyrosine kinase inhibitor.
Parallel studies of this same delivery system demonstrated it could provide 6 months of therapeutic levels of drug treatment for wet AMD using a VEGF-induced retinal leakage model (Elhayek et al. ARVO E-Abstract 1968).