Officials with the FDA have approved the supplemental New Drug Application (sNDA) for doravirine (Pifeltro, Merck) and doravirine/lamivudine/tenofovir/disoproxil fumarate (Delstrigo) for switching use to appropriate adult patients with HIV who are virologically suppressed, according to a press release.

Both Pifeltro and Delstrigo were approved by the FDA in August 2018 for the treatment of HIV in adults with no prior antiretroviral treatment history. The expanded indication includes adults on a stable antiretroviral regimen with no history of treatment failures and no known substitutions associated with resistance to the medications.

“Thanks to developments in HIV science, more treatments are becoming available to address the medical needs of people living with HIV,” Princy Kumar, MD, chief of the division of infectious diseases and tropical medicine at MedStart Georgetown University Hospital and professor of medicine and microbiology at Georgetown University School of Medicine, Washington, DC, said in a statement. “The expanded indications offer certain people with HIV-1 infection, and their doctors, the choice to switch their current antiretroviral therapy to Delstrigo or Pifeltro in combination with other antiretroviral agents.”

The latest approval is based on results from the phase 3 DRIVE-SHIFT trial, which evaluated switching 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. The baseline regimen included 2 nucleoside reverse transcriptase inhibitors (NRTIs) in combination with a protease inhibitor plus either ritonavir or cobicistat, or elvitegravir plus cobicistat, or an NNRTI.

The study included 670 patients who either began treatment with Delstrigo on day 1 (immediate switch group) or after 24 weeks (delayed switch group).

According to the data:
  • Two percent of patients in the immediate switch group had HIV-1 RNA ≥50 copies/mL at week 48 compared with 1% in the baseline regimen at week 24.
  • Ninety-one percent of patients who switched to Delstrigo immediately had HIV-1 RNA copies <50 copies/mL at week 48.
  • Ninety-five percent of patients who continued on their baseline regimen had HIV-1 RNA <50 copies/mL at week 24.
  • At week 24, patients in the immediate switch group showed statistically significant differences in changes from baseline in fasting low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol compared with those who continued on a boosted protease inhibitor regimen.
The safety profile among patients in the study was similar to patients with no antiretroviral treatment history, according to the release.

According to Merck, the Pifeltro and Delstrigo combination can be co-administered with a wide range of non-antiretroviral agents, and Pifeltro can be co-administered with a wide range of non-antiretroviral agents.

Reference

Merck’s Pifeltro (doravirine) and Delstrigo (doravirine/lamivudine/tenofovir/disoproxil fumarate) receive US FDA approval for use in appropriate adults living with HIV-1 who are virologically suppressed [news release]. Merck. https://www.mrknewsroom.com/news-release/prescription-medicine-news/mercks-pifeltro-doravirine-and-delstrigo-doravirinelamivudin. Accessed September 20, 2019.