The extent to which switching from one efavirenz-containing HIV medication to another option results in neurocognitive improvements may vary significantly depending on the type of measurements used, a small study published in Journal of Acquired Immune Deficiency Syndrome showed.
The final study results included data on 48 men who were virologically suppressed on efavirenz/emtricitabine/tenofovir disoproxil fumarate (Atripla) and had no neurocognitive symptoms at baseline. They were randomized 2:1 to either switch to emtricitabine/rilpivirine/tenofovir disoproxil fumarate (Eviplera) or remain on their current regimen. All participants completed extensive neuropsychological assessments (NPA) at baseline and week 12 (study end).
By week 12, NPA scores had improved similarly for both study groups overall, although participants who switched off of efavirenz scored objectively better within two specific cognitive function domains: attention and speed of information processing. That said, only five of the 34 participants (15%) who switched medications experienced an overall objective score improvement that was significantly greater than those who did not switch.
By contrast, 25 of the participants (74%) in the switch group reported subjective improvements in cognitive function, leading them to elect to remain on an efavirenz-free regimen mostly because of perceived benefits in their daily life, even though emtricitabine/rilpivirine/tenofovir disoproxil fumarate has dietary restrictions and efavirenz/emtricitabine/tenofovir disoproxil fumarate does not.
Based on their results, the study authors cautioned that it may be difficult to predict which cognitively asymptomatic patients might benefit from a switch off of efavirenz, due to the potential gap between objective and subjective measurements of the effects of such a change.