The Food and Drug Administration (FDA) has approved Pifeltro (doravirine; Merck), in combination with other antiretroviral agents, and Delstrigo (doravirine, lamivudine, tenofovir disoproxil fumarate; Merck) for the treatment of HIV-1 infection in adult patients to replace the current antiretroviral regimen in those who are virologically suppressed (HIV-1 RNA <50 copies/mL) on a stable antiretroviral regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine. Previously, both treatments were only approved for patients with no prior antiretroviral treatment history.

Delstrigo combines doravirine, a new non-nucleoside reverse transcriptase inhibitor (NNRTI), with lamivudine and tenofovir disoproxil fumarate, 2 nucleoside analogue reverse transcriptase inhibitors (NRTIs). It is approved for use as a complete regimen for the treatment of HIV-1 infection.

The approval was based on data from the phase 3 DRIVE-SHIFT trial (N=670), an open-label study evaluating a switch to Delstrigo in virologically suppressed patients on a baseline regimen for at least 6 months prior to trial entry with no history of virologic failure. Patients were randomized to either switch to Delstrigo at baseline (n=447; Immediate Switch Group [ISG]) or stay on their baseline regimen (2 nucleoside reverse transcriptase inhibitors [NRTIs] in combination with a protease inhibitor plus either ritonavir or cobicistat, or elvitegravir plus cobicistat, or an NNRTI) until Week 24, at which point they switched to Delstrigo (n=223; Delayed Switch Group [DSG]). 

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The primary efficacy comparison was between the Delstrigo ISG at Week 48 and the baseline regimen DSG at Week 24. Virologic outcome results showed that 2% of the Delstrigo ISG had HIV-1 RNA ≥50 copies/mL at Week 48 compared with 1% in the baseline regimen DSG at Week 24 (treatment difference: 0.7%, 95% CI, -1.3, 2.6). In addition, 91% of patients in the Delstrigo ISG had HIV-1 RNA <50 copies/mL at Week 48 vs 95% of patients in the DSG at Week 24. The safety profile in virologically-suppressed patients was observed to be similar to that seen in patients with no antiretroviral treatment history. 

Delstrigo is available as 100mg/300mg/300mg strength tablets in 30-count bottles. Pifeltro is available as 100mg strength tablets in 30-count bottles.

For more information visit merck.com.

This article originally appeared on MPR