A 2-drug regimen of dolutegravir (ViiV Healthcare) and rilpivirine (Janssen Sciences Ireland UC) achieved non-inferior viral suppression (HIV-1 RNA <50 copies/millilitre) at 48 weeks compared with a 3- or 4-drug regimen, according to data from the SWORD 1 and SWORD 2 studies presented this week at the annual Conference on Retroviruses and Opportunistic Infections in Seattle.

The program comprises 2 studies with over 1000 patients who previously achieved viral suppression on a 3- or 4-drug (integrase strand transfer inhibitor[INSTI]-, non-nucleoside reverse transcriptase inhibitor [NNRTI]-, or protease inhibitor [PI]-based) antiretroviral regimen. Five hundred and eleven patietns were randomly assigned to stay on their 3- or 4-drug regimen and 513 patients switched to a dolutegravir and rilpivirine regimen.

Virologic failure rates were <1% in the dolutegravir and rilpivirine arm and 1% in the 3- or 4- antiretroviral-drug arm. No INSTI resistance-associated mutations were reported.

The overall rate of serious adverse events was comparable between treatment groups (dolutegravir + rilpivirine: 27, CAR: 21). As would be expected when switching from a stable regimen to a new regimen, more adverse events were reported and led to withdrawal from the study in the dolutegravir and rilpivirine arm compared to the current antiretroviral therapy (CAR) arm (dolutegravir + rilpivirine: 21, CAR: 3).

The most commonly reported (>5%) adverse events in the dolutegravir and rilpivirine arm were nasopharyngitis, headache, diarrhea, and upper respiratory tract infection. For the CAR arm, the most commonly reported adverse events were nasopharyngitis, upper respiratory tract infection, back pain, headache, and diarrhea. The studies are ongoing for 148 weeks.

The safety profiles for dolutegravir and rilpivirine in these studies were consistent with the product labelling for each medicine. 

Use of dolutegravir and rilpivirine as a 2-drug regimen for HIV-1 maintenance therapy is investigational and not approved anywhere in the world.

ViiV Healthcare is a specialist HIV company majority-owned by GSK, with Pfizer Inc. and Shionogi Limited as shareholders. 

Reference

Llibre JM, et al. Phase III SWORD 1 & 2: Switch to DTG+RPV maintains virologic suppression through 48 weeks. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 13-16, 2017; Seattle.