Pilot study of a novel short-cycle antiretroviral treatment interruption strategy: 48-week results of the five-days-on, two-days-off (FOTO) study

Purpose: The challenges associated with daily lifelong antiretroviral therapy (ART) have stimulated interest in alternative treatment schedules, including planned, cyclical interruptions of therapy in patients with virologic suppression and sufficient CD4(+) T-cell counts. Method: We conducted a 48-week, open-label, single-arm, prospective pilot study of a novel short-cycle treatment interruption strategy. Upon enrollment, 30 HIV+ individuals with a history of durable viral suppression on daily ART changed their weekly treatment schedule to 5 consecutive days on treatment (typically Monday through Friday) followed by 2 days off treatment (five-on, two-off, or FOTO treatment schedule). Results: At 24 and 48 weeks, as-treated analysis revealed that virologic suppression was maintained in 26/29 subjects (89.6%), including 100% of subjects taking efavirenz-based regimens. Participants adhered well to the FOTO treatment schedule and expressed a strong preference for the FOTO treatment schedule compared to daily ART Conclusion: If validated, the FOTO treatment strategy with efavirenz-based regimens could avoid the viremia witnessed in longer cycle structured treatment interruptions yet still ameliorate a number of problems associated with the current paradigm of daily ART for HIV infection, including the high cost of therapy and the pill fatigue that, in many patients, leads to erratic adherence and ultimately treatment failure.