and Antonella d’Arminio Monforte,3 for the Italian Cohort Naive Antiretrovirals Study Groupa

The association between minor mutations in human immu-nodeficiency virus (HIV) protease at baseline and development of common primary mutation 90M at virological failure (con-ferring some resistance to all protease inhibitors [PIs]) was evaluated in 93 previously drug-naive patients experiencing failure of their first PI-based antiretroviral regimens. In logistic regression analysis, the probability of accumulating a new 90M mutation at virological failure was associated with the presence at baseline of minor mutation 36I (naturally occurring in ∼25 % of HIV clade B and in 180 % of HIV non-clade-B viruses) (adjusted odds ratio, 13.5 [95 % confidence interval, 1.89–95.6];) and, possibly, of 10I/V. This suggests a potential rolePp.009 for the presence of 36I at baseline in predicting the appearance of 90M at virological failure. Experimental and clinical evidence supports the use of drug-resistance testing in HIV-infected patients receiving therapy an