Hep C Drug Sovaldi May Interact Harmfully With HIV Drug Viread

Sovaldi, included in Harvoni and Epclusa, may affect a key liver enzyme that activates the HIV drug Viread.

December 28, 2016

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Sovaldi (sofosbuvir)-based hepatitis C virus (HCV) regimens may negatively affect the body’s ability to process the commonly prescribed HIV antiretroviral (ARV), Viread (tenofovir disoproxil fumarate, or TDF), Healio reports.


Sovaldi is included in the fixed-dose combination hep C regimens Harvoni (ledipasvir/sofosbuvir) and Epclusa (sofosbuvir/velpatasvir) and is also used in combination with other stand-alone tablets such as Daklinza (daclatasvir) and Olysio (simeprevir).


Viread (tenofovir disoproxil fumarate, or TDF) is included in Truvada (TDF/emtricitabine), Atripla (efavirenz/TDF/emtricitabine), Stribild (elvitegravir/cobicistat/emtricitabine/TDF) and Complera (rilpivirine/TDF/emtricitabine).


Publishing their findings in the Journal of Hepatology, researchers studied small portions of cells known as microsomes taken from the liver cells of 20 people and the kidney cells of 12 people. 
They found that Sovaldi inhibited the chemical breakdown, or hydrolysis, of both liver and kidney microsomes and that the drug inhibited the enzyme carboxylesterase-2 (CES-2).


CES-2 is known for its detoxification effects and is found in great quantities in the liver and kidney. It normally breaks down through hydrolysis and activates Viread.


The researchers believe that the Sovaldi-prompted inhibition of the enzyme may have implications for Viread-related kidney toxicity. They recommend that people take these two drugs at different times or administer them in different ways, i.e., not both as oral drugs, until clinical trials can fully analyze the risks of combining them.


To read the Healio article, click here.

To read the Journal of Hepatology letter, click here.

Read more articles from POZ, here.