Gilead Sciences’ Harvoni (ledipasvir/sofosbuvir) and the combination of Gilead’s Sovaldi (sofosbuvir) and Bristol-Myers Squibb’s as-yet-unapproved daclatasvir were the least likely to cause a severe reaction with the HIV regimens of a cohort of HIV/hepatitis C virus (HCV) coinfected adults, the National AIDS Treatment Advocacy Project reports. Reporting their findings at the 16th International Workshop on Clinical Pharmacology of HIV and Hepatitis Therapy in Washington, DC, researchers conducted a retrospective study in which they examined the HIV regimens of 125 coinfected patients at a Denver hospital and predicted how they would interact with hep C regimens.

The investigators determined the potential drug-drug interactions (DDIs) between each individual’s HIV regimen and four hep C regimens: Janssen’s Olysio (simeprevir) and Sovaldi; AbbVie’s Viekira Pak (ombitasvir/paritaprevir/ritonavir; dasabuvir); Harvoni; and Sovaldi and daclatasvir. They categorized potential DDIs as severe (unsafe and not recommended), moderate (requiring monitoring and/or dose adjustments), and having no significant interactions (safe, with no dose adjusting needed).

A total of 101 (81 percent) of the participants were taking Viread (tenofovir), 50 (40 percent) took a protease inhibitor, 44 (35 percent) took Isentress (raltegravir), and 20 (16 percent) took Sustiva (efavirenz).

Researchers predicted that 88 (70 percent) of the participants could have moderate or severe DDIs with at least one of the four hep C regimens. Such DDIs would be expected with 70 percent of the HIV regimens if combined with Olysio/Sovaldi, 61 percent with Viekira Pak, 64 percent with Harvoni, and 47 percent with Sovaldi/daclatasvir.

The proportion of the HIV regimens that would cause severe DDIs with the respective hep C regimens were as follows: 64 percent with Olysio/Sovaldi, 41 percent with Viekira Pak, 10 percent with Harvoni, and none with Sovaldi/daclatasvir.

To read the NATAP report, click here.