Combined effects of genetic and non-genetic risk factors affect response to ranibizumab in exudative age-related macular degeneration

Purpose: To investigate whether genetic and non-genetic risk factors influence 12-month response to ranibizumab treatment for exudative age-related macular degeneration (AMD). Methods: A cohort of 94 Caucasian patients with unilateral exudative AMD received intravitreal ranibizumab. After a three-injection loading phase, a PRN regimen was followed. Patients were genotyped for three single-nucleotide polymorphisms: CFH rs1061170, ARMS2 rs10490924 and C3 rs2230199. Nongenetic risk factors [choroidal neovascularization (CNV) phenotype, smoking habit, hypertension and body mass index] were considered. The selected endpoint was the 12-month variation of number of ETDRS letters. Results: Complement factor H (CFH) risk alleles, smoking history and arterial hypertension each independently influenced treatment response, with worse 12- month BCVA outcomes (p = 0.036, 0.037, 0.043, respectively). A significant cumulative effect of these risk factors was also observed: patients homozygous for the CFH risk alleles and with a positive smoking history showed a mean loss of 8.0 ETDRS letters (p = 0.010). Patients with CFH risk alleles, smoking history and hypertension had a mean loss of 13.9 ETDRS letters (p = 0.013). CNV phenotypes did not influence visual outcomes, nor were they associated with other genetic/non-genetic risk factors. Conclusions: Complement factor H risk alleles, smoking history and hypertension affect the mid-term response to ranibizumab in exudative AMD.