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.