People taking Prezista (darunavir) for HIV treatment may experience improvements in their cholesterol and triglyceride levels, collectively known as lipids, after switching their “booster” drug from Norvir (ritonavir) to Tybost (cobicistat).

Norvir and Tybost are each used to raise the level of antiretrovirals (ARVs) in the body. Prezista is combined with Tybost in Prezcobix (darunavir/cobicistat).

Spanish researchers conducted a retrospective, observational study of shifts in blood lipids after 299 people with HIV switched their boosting agent from Norvir to Tybost between December 2015 and May 2016. Nearly half of the participants were initially taking just Prezista and Norvir, 9 percent were taking those two drugs plus one additional ARV and 41.5 percent were taking two additional ARVs.

The members of the study cohort all had their fasting lipid levels tested just prior to switching boosters, and then again after six months.

The researchers defined high cholesterol as total cholesterol higher than 200 or LDL cholesterol above 130. High triglycerides was defined as triglycerides above 200.

Fifty-two percent of the study cohort members had abnormal lipids.

Overall, the booster swap did not affect cholesterol levels, although the median triglyceride level did decline. When the researchers only looked at the shift in lipids among those with abnormal levels at the outset, the investigators found that there was a significant decline in total cholesterol and LDL cholesterol, an increase in good cholesterol and a decline in triglycerides.

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To read the study abstract, click here.