Get to Know the Integrase Inhibitors

Anti-HIV drugs can be divided into several classes, such as nukes, non-nukes, protease inhibitors, co-receptor blockers and so on. The latest class of medicines for the treatment of HIV is called integrase inhibitors. The following are two commonly used integrase inhibitors:

  • raltegravir (Isentress)
  • elvitegravir (in Stribild, a pill that also contains cobicistat, tenofovir and FTC)

Integrase inhibitors are generally well tolerated and tend to have fewer side effects than other commonly used HIV medications. Raltegravir in particular has had relatively few interactions with other drugs.

Until recently, integrase inhibitors have had to be taken either twice daily (as is the case with raltegravir) or with a boosting agent (another drug that raises the level of the integrase inhibitor or other drugs). A boosting agent commonly used in HIV treatment is ritonavir (Norvir, also in Kaletra).

A newer boosting agent is cobicistat. So far in North America cobicistat is found only inside a pill called Stribild. The purpose of cobicistat is to boost the concentration of elvitegravir so it can be taken just once daily. Stribild has to be taken with food, as this increases its absorption. Cobicistat is therefore very useful as a boosting agent, allowing for convenience and hopefully easier adherence. However, cobicistat interacts with many other medicines.

Enter Dolutegravir

Dolutegravir is the third integrase inhibitor that's been tested on a large scale for HIV treatment. There are several factors that make dolutegravir unique as an integrase inhibitor -- it does not need a boosting agent and it can be safely taken once daily. Other factors concern its resistance profile, tolerability and anti-HIV activity, which we will explore in this issue of TreatmentUpdate.

Dolutegravir (sold under the brand name Tivicay) was approved in August in the U.S. and in October in Canada and is on track to be approved in the European Union and other countries.