John Mellors, MD, professor of medicine and chief of infectious diseases at the University of Pittsburgh, and Sharon Kemp, director of HIV Research for Virco UK in Cambridge, United Kingdom, answer questions about a study presented at the 5th International Workshop on HIV Resistance and Treatment Strategies, held in June in Scottsdale, AZ. The study found that a change at position 318 in the genetic code of HIV can make the virus highly resistant to treatment with non-nucleoside reverse transcription.