Brand name: Not yet established
Generic name: elvitegravir, or EVG
Class: Integrase inhibitor (integrase strand transfer inhibitor, or INSTI)
Manufacturer: Gilead Sciences, Inc., www.gilead.com, (800) GILEAD-5 (445-3235)
AWP: TBD; investigational drug at press time.
Standard Dose: One 150 mg or one 85 mg tablet once a day boosted with either Norvir or cobicistat. The dose depends on drug interactions with the co-administered PI. Take missed dose as soon as possible, unless it is closer in time to your next dose. Do not double up on your next dose.
Potential side effects and toxicity: Seen in clinical studies: diarrhea, upper respiratory tract infection, bronchitis, back pain, depression, sinusitis, joint pain, nausea, and urinary tract infection. The incidence of these side effects were the same as seen with Isentress in one clinical study (3% to 6%), with the exception of diarrhea, seen more often (12% vs. 7%). Laboratory abnormalities indicating potential liver damage (GGT, ALT, and AST) were lower with elvitegravir (3% vs. 6%, 2% vs. 5%, and 1% vs. 5%, respectively for elvitegravir and Isentress). Available data are limited due to investigational drug status. See chart for potential drug class side effects.
Potential drug interactions: Elvitegravir is expected to interact with many other drugs. Tell your provider or pharmacist about all medications, herbs, and supplements you are taking or thinking of taking, prescribed or not. Elvitegravir is metabolized primarily by the enzyme CYP450-3A (known as the P450 pathway) and any medications that affect this enzyme may affect the levels of elvitegravir. The smaller 85 mg dose must be used with Reyataz or Kaletra. Again, available data are limited due to investigational drug status.
More information: Not yet approved, Gilead plans to file for FDA approval in the second quarter of 2012. The 96-week data from Study 145 will be submitted for presentation at a scientific conference this year. In Study 145, advanced Phase 3 research, elvitegravir was found to be non-inferior (no better, no worse) to Isentress, the only INSTI on the market at press time, in treatment-experienced people (this group, on average, does not respond as well as people taking HIV therapy for the first time). At 96 weeks of therapy, 48% of patients in the elvitegravir group and 45% of patients in the Isentress group achieved an undetectable viral load of less than 50 copies per mL. At 48 weeks both averaged an increase in CD4+ T-cell count of about 143. The 96-week CD4 data are not yet available. At 48 weeks there was no drug resistance benefit with elvitegravir -- in the people whose treatment failed with either drug, the same incidence of HIV resistance to the INSTI class of drugs was seen (27% for elvitegravir vs. 21% for Isentress). Providers may want to order a resistance test that can measure INSTI resistance (standard tests cannot). Elvitegravir is also being studied in a fixed dose, single-tablet regimen (see the "Quad" page). See package insert, when available, for more complete information on potential side effects and interactions.
Elvitegravir is an investigational integrase inhibitor that is expected to be approved later this year, initially in a "Quad" single-tablet co-formulation that also includes tenofovir, emtricitabine, and the booster cobicistat. Boosting of elvitegravir is required to make it a once-daily drug. In recent clinical trials, the Quad appears to be as effective as Atripla or the combination of Truvada plus Reyataz/Norvir for initial therapy. Elvitegravir can also be used by treatment-experienced patients, but those who have developed resistance to Isentress are likely to have cross-resistance to elvitegravir.
-- Joel Gallant, M.D., M.P.H.
The jury is still out on this one. Elvitegravir will be convenient and another wonderful "easy to follow" drug cocktail when packaged in the "Quad" with three other drugs for a nice, new STR (single-tablet regimen). As an individual agent, however, it may not make much of a splash in the drug combo world. As a "me too" drug in the newest class, integrase inhibitors, this drug has the same genetic weaknesses as Isentress, so using it after failing Isentress is not an option.
-- Joey Wynn