A novel gene therapy, ABBV-RGX-314, has shown promising results in a phase II study for the treatment of bilateral neovascular age-related macular degeneration (AMD). The study, presented at the American Academy of Ophthalmology (AAO) meeting, demonstrated that the gene therapy was well-tolerated and significantly reduced the need for frequent injections in patients with the condition.
The research involved a subset of patients already participating in clinical trials for neovascular AMD, who received subretinal gene therapy with ABBV-RGX-314 in their fellow eye. This marked the first instance of subretinal gene therapy being administered in both eyes for neovascular AMD. The primary goals were to assess the therapy's safety and efficacy in a bilateral setting, particularly considering the potential for varying responses due to neutralizing antibodies and immune reactions.
Key Findings
The study included 10 patients who had previously undergone extensive treatment, averaging around eight injections in the 12 months prior to the gene therapy. Following a single injection of ABBV-RGX-314, the results indicated no new safety concerns, such as intraocular inflammation. Pigmentary changes, a known side effect from previous data sets, were observed in some patients.
Efficacy results were notable, with 78% of patients requiring no supplemental injections within a 9-month period. The remaining 22% needed only one additional injection. Overall, the treatment burden was reduced by 97%. Protein production levels, indicative of the gene therapy's mechanism (producing an anti-VEGF fab similar to ranibizumab), were comparable to those observed in the patients' first treated eyes.
Expert Commentary
Arshad Khanani, MD, director of clinical research at Sierra Eye Associates, who presented the data at AAO, highlighted the significance of these findings. "It was very exciting to share the data... We can actually perform treatment in both eyes without any new signals of safety and efficacy," he stated.
Yasha Modi, MD, assistant clinical professor at New York University Langone Health, emphasized the importance of evaluating each gene therapy individually. "I think you have to look at each drug separately... different programs have had different complications," Modi noted, particularly pointing out the varying inflammatory responses associated with different delivery methods, such as intravitreal versus subretinal.
Implications for Future Research
While the results are promising, experts agree that further research is needed to fully understand the long-term effects and optimal use of ABBV-RGX-314 and other gene therapies for neovascular AMD. The success of this study may pave the way for fellow eye studies with other companies to alleviate fears and improve treatment options.
