A study of HIV-positive people in Switzerland and Spain shows that structured treatment interruptions do not result in improvements in the immune system, quashing theories that drug breaks would prime immune cells to better recognize and destroy HIV in the body. Some researchers had speculated that by repeatedly allowing HIV to surge in the body during treatment breaks then suppressing the virus when anti-HIV drugs were restarted would result in heightened immune activity against HIV. But the study of 113 HIV-positive Swiss and Spanish patients showed that four cycles of eight weeks on/two weeks off drug treatment, followed by an indefinite halt to treatment, produced no immunological benefit. Only 17% of the patients were able to maintain viral loads under 5,000 copies at the one-year mark of the study, with only 7% holding viral levels low after 96 weeks. T-cell counts also dropped an average of 177 cells during the first 12 weeks after treatment was indefinitely stopped but stabilized thereafter.
The authors conclude, "Results of this study do not favor the autovaccination hypothesis," the term given to the theory that treatment breaks can improve immune responses to HIV. "Treatment interruptions did not provoke clinical complications, and there was little drug resistance, but comparative trials will have to show what benefit, if any, is associated with intermittent, as opposed to continuous treatment." The full study appears in the May 26 edition of the Archives of Internal Medicine.