Minor mutations in HIV protease at baseline and appearance of primary mutation 90M in patients for whom their first protease-inhibitor antiretroviral regimens failed

The association between minor mutations in human immunodeficiency virus (HIV) protease at baseline and development of common primary mutation 90M at virological failure (conferring 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 361 (naturally occurring in ∼25% of HIV clade B and in >80% of HIV non-clade-B viruses) (adjusted odds ratio, 13.5 [95% confidence interval, 1.89-95.6]; P = .009) and, possibly, of 10I/V. This suggests a potential role for the presence of 361 at baseline in predicting the appearance of 90M at virological failure.