Conference Coverage

Switch to integrase inhibitor regimen safe and effective


Switching patients with HIV from a protease inhibitor–based antiretroviral therapy regimen to an integrase inhibitor–based regimen can be performed safely, with maintenance of high levels of virologic suppression and improvements in both bone mineral density and renal function biomarkers, data from a randomized trial indicate.

Among 212 women with successful HIV virologic suppression following 48 weeks of treatment with ritonavir-boosted atazanavir plus tenofovir disoproxil fumarate (ATV/r +TDF), among those who were switched to continued therapy with an integrase inhibitor–based regimen of elvitegravir/cobicistat/emtricitabine and tenofovir alafenamide (E/C/F/TAF), mean increases in lumbar spine bone mineral density (BMD) were greater and renal function was improved compared with patients who were maintained with ATV/r + TDF, reported Monica Thormann, MD, from Salvador B. Gautier Hospital in Santo Domingo, Dominican Republic, and colleagues at the HIV Glasgow drug therapy meeting, which was held online in 2020.

Although the E/C/F/TAF regimen was associated with a significantly greater increase in lipids, there was no significant change in the total cholesterol to high-density lipoprotein (HDL) cholesterol ratio.

The patients in the study had previously participated in a blinded randomized trial comparing the integrase inhibitor combination plus TDF with ATV/r + TDF in treatment-naive women.

In the current study, patients were randomly assigned in a 3:1 ratio to maintenance with either E/C/F/TAF (159 patients) or ATV/r + TDF (53 patients).

Forty-eight weeks after the switch, virologic suppression (to fewer than 50 copies/mL) was maintained among 94.3% of those on the integrase inhibitor–based regimen, compared with 86.8% of those on the protease inhibitor–based regimen. Virologic failure was seen in 1.9% of those on the integrase inhibitor–based regimen and in 3.8% of those on the protease inhibitor–based regimen.

In addition, virologic suppression below 20 c/mL at week 48 was more common among women maintained on E/C/F/TAF, at 84.9% vs 71.7% (P = .041). No treatment-emergent resistance was seen with either regimen.

As noted, there were higher mean percentage increases in BMD in the E/C/F/TAF group for both total hip and lumbar spine, but only the latter measure improved significantly in comparison with patients treated with ATV/r + TDF (2.82% vs 0%, P < .001).

Markers of renal tubule damage, including the beta-2 microglobulin to creatinine ratio and the rentinol-binding protein to creatinine ratio, were significantly improved with the integrase inhibitor regimen.

Increases in total cholesterol, LDL cholesterol, and HDL cholesterol were 27 vs 5 mg/dL, 16 vs 8 mg/dL, and 5 vs 0 mg/dL in each case comparing the integrase inhibitor–based regimen to the protease inhibitor–based regimen. All of those comparisons were statistically significant.

As noted, however, the total cholesterol to HDL cholesterol ratio was not significantly different between the treatment arms. The rate or initiation of lipid-modifying agents was 1.3% in the E/C/F/TAF group vs 0 in the ATV/r + TDF group, but this difference was not statistically significant.

“These data demonstrate that women who switch to an integrase inhibitor + TAF‐based regimen maintain high levels of virologic suppression with improvement in BMD and renal function biomarkers, as compared with those remaining on their ritonavir boosted atazanavir + TDF‐based regimen,” the authors wrote.

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