First-Line Triple-Combination Antiretroviral Therapy Provides Long-Term Protection Against AIDS-Related Illnesses, Study Says
First-line triple-combination antiretroviral therapy provides long-term protection against AIDS-related illnesses, according to a study published Friday in the Lancet, AFP/Google.com reports. The three first-line classes of antiretrovirals are nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors.
For the study, Andrew Phillips of the Royal Free and University College Medical School and colleagues followed 7,916 HIV-positive people living in the United Kingdom who began standard triple-combination therapy. The researchers found that 167 of the participants developed extensive resistance to all three types of drugs and that the resistance was higher among those who began treatment when their CD4+ T cell counts were lower than 200 (AFP/Google.com, 12/7).
The cumulative risk of extensive triple-combination resistance at the end of 10 years was 9.2%, but the risk decreased over time, the study found. The risk of death after five years of developing drug resistance is about 10.6%, according to the study (Phillips et al., Lancet, 12/7). Of the participants who developed drug resistance, 90% were resistant to seven first-line antiretrovirals. Fifty-eight percent of those who were resistant to first-line drugs also were resistant to second-line drugs, the study found (AFP/Google.com, 12/7).
The researchers noted that the study's findings will have implications in developing countries, where "additional drugs outside these classes are unlikely to be available for some time" (Lancet, 12/7). According to the World Health Organization, more than two million people worldwide were receiving standard triple-combination therapy at the end of 2006 -- a 54% increase compared with 2005.
The finding that 58% of those who developed resistance to first-line drugs also developed resistance to second-line drugs "has implications for the treatment of patients in developing countries," Edward Mills -- of the British Columbia Centre for Excellence in HIV/AIDS -- and Jean Nachega -- of Johns Hopkins University -- write in a commentary that accompanies the study. Mills and Nachega add that in developing countries, "only one or two regimens are normally available, which results in disastrous consequences when these regimes fail."
Mills and Nachega noted that the study participants typically began treatment earlier, when their immune systems had a greater capacity to fight HIV, compared with people living in developing countries (AFP/Google.com, 12/7).
An abstract of the study is available online.