Marcelin et al (2007) identified nine protease codons (L10F/ I/ M/ R/ V, I15A/ V, K20I/ M/ R/ T, L24I, I62V, G73S/ T, V82A/ F/ S/ T, I84V, L90M) that were associated with decreased virological response to saquinavir/ ritonavir (1000/ 100 mg twice daily) in 138 saquinavir naive patients.