At the 2015 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, results from the 11-country BREATHER Study showed viral control in the great majority of youth who took their regimen for five days but then skipped two. This may offer younger patients a novel way to keep HIV under control while addressing common adherence issues seen in many youth.
However, the study researchers greatly caution against using this short-cycle dosing strategy until more data is collected to confirm that it's safe. These 48-week results apply only to youth on Sustiva-based regimens with well controlled HIV and no viral rebounds before starting the new dosing. Nearly all of the youth will be followed for another 96 weeks.
BREATHER followed 199 youth aged 8-24 years, all of whom took a regimen that included Sustiva (efavirenz). One out of five was 18 or older. Half were randomized to take their regimens daily as they had been doing up to study entry while the other half adopted the novel short-cycle dosing of 5 days on and 2 days off ... essentially the week on with the weekend off.
Everyone who enrolled had already had at least one year of viral loads below 50 copies. None had ever had a viral rebound while on treatment with efavirenz (which greatly reduces the risk for resistant HIV). Everyone had blood work done at 0, 4, 12, 24, 36 and 48 weeks. Just over half were male with median CD4 counts of 793.
After 48 weeks, six on the 5-on/2-off schedule and seven on the daily schedule had developed detectable viral loads >50 copies. When looking at viral loads >400 at week 48, two on the novel dosing and four on daily dosing had viral rebounds. There were no significant differences in lab side effects or inflammation markers between the two groups.
The presentation mentioned that 3 out of 4 of those on the novel schedule said it made their lives a lot easier. They also said their side effects had eased up over the weekends on the new schedule.
Other studies that have looked at weeks or months off treatment (structured treatment interruptions, or STIs) have shown poor results, with increased risks of AIDS- and non-AIDS-related conditions. However, the BREATHER Study researchers were clear to state that this was not an STI study. Again, they greatly caution against anyone -- youth or older -- to attempt this dosing schedule until more long-term follow-up study can ensure this is a safe and effective strategy over time.