Newly presented data from the DISCOVER trial evaluating emtricitabine 200 mg and tenofovir alafenamide 25 mg tablets (F/TAF) demonstrated continued non-inferior efficacy to emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg (F/TDF) for pre-exposure prophylaxis (PrEP).
Additionally, 96-week results indicate that when compared with F/TDF, F/TAF had favorable changes in key markers of renal and bone safety among trial participants of various ages.
Data from the 96-week analysis of the DISCOVER study were presented in a virtual session of the Conference on Retroviruses and Opportunistic Infections (CROI 2020
According to investigators, differences were also observed in lipid parameters and changes in baseline weight. At this time, the long-term significance of these differences is not fully understood, but the presenters of the data remark that these measures are critical to assess as individuals use PrEP for longer periods of time.
Specifically, in the study, there was a statistically significant difference in renal safety which favored F/TAF at Week 96. These differences were observed in both the overall study population, and in older individuals with moderate renal impairment (baseline eGFR=60-≤90 mL/min).
It was also reported that in participants over the age of 50 years who received F/TAF had a smaller decrease in median estimated glomerular filtration when compared with individuals who received F/TDF (1 mL/min versus -6 mL/min, respectively).
According to 96-week results, there were differences favoring treatment with F/TAF in “makers of proximal tubular function (β2-microglobulin:creatinine ratio and retinol binding protein: creatinine ratio).” Additionally, study participants with moderate renal impairment who received F/TAF had smaller changes in both eGFR and markers of proximal tubular function.
Among a sub-group, it was observed that eGFR increased by 3 mL/min in participants taking F/TAF and decreased by 1 mL/min in individuals taking F/TDF.
Additionally, presenters report that there were changes in bone mineral density (BMD) that favored F/TAF in the overall study population and individuals younger than 25 years. In the younger individuals, spine BMD increased by 1.39% among individuals treated with F/TAF and decreased by 1.2% those treated with F/TDF. Furthermore, hip bone mineral density increased 1.21% in the F/TAF group and decreased 1.7% in the F/TDF group.
Study participants who received F/TDF had decreases in lipid levels after both 48 and 96 weeks, yet individuals who received F/TAF had stable lipid levels through 96 weeks.
The presenters also note that fasting glucose levels were similar between the 2 groups and that participants in the F/TDF group had smaller mean weight increases compared with those in the F/TAF group at 96 weeks. (+0.5 kg vs. +1.7 kg, respectively).
“F/TAF is a safe, longer-term option for PrEP, with certain subgroups experiencing a greater magnitude of benefit in BMD and renal biomarkers,” the investigators concluded in their abstract.
The study, Longer-term safety of F/TAF and F/TDF for HIV PrEP: DISCOVER Trial 96-Week Results, was presented in a virtual session of CROI 2020.
>> Read a Q&A with Onyema Ogbuagu, MD, presenting author.
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