Given the established relationship between Aβ and CFI in modulating the alternative complement cascade, and in support of the GSK933776 development program in AMD (geographic atrophy), we asked the following questions: (1) Are Aβ peptides (1–40 or 1–42) able to reduce CFI bioactivity to convert C3b to iC3b in an in vitro cofactor assay? This evidence concerns the gene CFI and age-related macular degeneration.