Christian Callebaut, Clinical Virology, Gilead USA, presented the findings of their clinical trial GS-US-292-0119.

Virologically suppressed, treatment-experienced patients on complex multi-tablet regimens were randomised to either switch to a simpler, more convenient antiretroviral regimen or remain on their current optimised ART.

After 48 weeks:

All patients had documented resistance to 2 classes of antiretroviral (ARV) agents at baseline. Detailed ARV regimens and the resistance profile of the study population are described.

Study methods:

The Stanford HIVdb algorithm version 8.01 was used to calculate genotypic susceptibility scores (GSS).

For each drug, a 5-point scale was used:

 The total GSS for a given regimen was calculated as the sum of the scores for each individual drug. 

Results:

A total of 94.8% had documented resistance to 2 classes of ARVs, including:

The most common resistance associated mutations (RAMs) were:

Thymidine analog mutations (TAMs) were present in 42.2% of patients (59.6% with one or two TAMs and 40.4% with three TAMs). 

The distribution of GSS at study entry was similar across treatment groups.

Patients in the E/C/F/TAF DRV arm maintained virologic suppression similarly, regardless of the DRV dosage received before switching (33/33 and 51/56 with treatment success in the 600 mg BID and 800 mg QD groups, respectively).

In the E/C/F/TAF DRV arm,

Within each treatment group, patients maintained virologic suppression similarly regardless of their GSS at study entry.
 

Conclusions:

Details of the study can be found here: https://clinicaltrials.gov/ct2/show/study/NCT01968551