Progress toward personalized medicine for age-related macular degeneration

Non-responsiveness to intravitreal aflibercept treatment in neovascular age-related macular degeneration: implications of serous pigment epithelial detachment

The prognosis of neovascular age-related macular degeneration (AMD) has been improved by anti-vascular endothelial growth factor treatments, including intravitreal aflibercept (IVA) treatment. However, many patients remain incurable. In this study, we retrospectively evaluated non-responsiveness to IVA monotherapy at 12 months in 133 eyes of 133 AMD patients. Sixty-two patients were initially treatment-naive, and 71 had received other treatments before IVA (the treatment-switched group). Mean best-corrected visual acuity (BCVA) was improved in the treatment-naive group but not in the treatment-switched group, although mean central retinal thickness (CRT) decreased in both groups. The respective percentages of non-responders as determined by worsened BCVA in the treatment-naive and treatment-switched groups were 8.1% and 15.5%, and via fundus findings, they were 12.9% and 8.5%. Multivariate analyses adjusted for age, gender, CRT, and greatest linear dimension showed that serous pigment epithelial detachment (PED) at baseline was associated with non-responsiveness in both groups as determined by BCVA and by fundus findings, and fibrovascular PED measurements indicated no response as determined by fundus findings in the treatment-switched group. The results reported herein may assist the formulation of appropriate treatment protocols for AMD patients.

Genetic diversity and medicinal drug response in eye care

BACKGROUND

Individual variation in drug response and adverse drug reactions are a serious problem in medicine. This inter-individual variation in drug response could be due to multiple factors such as disease determinants, environmental and genetic factors. Much has been published in the literature in recent years about the potential of pharmacogenetic testing and individualized medicine. The development of personalized medicine is truly an exciting area of research.

METHODS

This pharmacogenetic concept in ophthalmology has existed for more than a century. Although substantial studies that link genetic variants to inter-individual difference in drug response have been reported in several diseases such as cancer and heart diseases, such studies are progressing slowly in the eye field. In this short article, an attempt has been made to summarize these results.

RESULTS

Recently, there have been some small-scale studies that seem to associate the drug response to the genotype of patients in two major eye disorders, namely age-related macular degeneration (ARMD) and glaucoma.

CONCLUSION

These studies are still in their infancy, and do not suggest that a pharmacogenetic basis of drug development is a credible concept and can become reality in the future. This is because most drug responses involve a large number of genes that have several polymorphisms and it is unlikely that any one single gene dictates the drug response. Therefore, a polygenic approach, whole genome single nucleotide polymorphism (SNP) analysis and a molecular understanding of disease itself may provide a better insight in the future about genetic predisposing factors for adverse drug reactions.