The U.S. Food and Drug Administration (FDA) announced today that it has granted approval to Tibotec’s Intelence (etravirine), the first new non-nucleoside reverse transcriptase inhibitor (NNRTI) in ten years. Intelence, at a dose of 200 mg twice a day, has been approved specifically for treatment-experienced HIV-positive patients with resistance to older NNRTIs and other ARVs.
The approval of Intelence is based on data from two clinical trials involving 1,200 highly treatment experienced HIV-positive adults. Intelence, when combined with other approved ARVs, reduced viral loads to undetectable in up to 60 percent of the patients who received the drug for 24 weeks, compared to 40 percent of those who received a placebo plus other HIV drugs. CD4 counts were also higher among those receiving Intelence, compared with those receiving placebo.
The side effects most commonly reported among study volunteers who received Intelence were rash and nausea.
Intelence works by blocking HIV’s reverse transcriptase enzyme. After HIV's genetic material is deposited inside a cell, its RNA must be converted (reverse transcribed) into DNA. NNRTIs stop this process and prevent HIV from infecting the CD4 cell and producing new virus particles.
A key advantage of Intelence is its resistance profile. Compared with older NNRTIs—efavirenz (found in Sustiva/Stocrin and Atripla), nevirapine (Viramune) and delavirdine (Rescriptor)—test tube studies suggest that multiple mutations in HIV’s reverse transcriptase enzyme are needed to weaken the drug’s effectiveness; only one mutation is needed to confer high-level resistance to efavirenz, nevirapine and delavirdine. What’s more, Intelence is active against HIV strains containing two key mutations that cause resistance to older NNRTIs—K103N and Y181C—making it the first NNRTI to offer potential benefits to patients who have virus that is no longer sensitive to efavirenz, nevirapine and delavirdine.
The correct Intelence dose for treatment-experienced patients is two 100 mg tablets, taken twice a day with food.
Until more complete drug interaction studies are conducted, Intelence should not be combined with many antiretrovirals, including Norvir (ritonavir)-boosted Aptivus (tipranavir), Lexiva (fosamprenavir) or Reyataz (atazanavir); full-dose Norvir; protease inhibitors given without a Norvir booster; and other NNRTIs. Intelence should be used cautiously with Kaletra (lopinavir/ritonavir).
Other drugs Intelence should not be used with include the anticonvulsants Tegretol (carbamezepine), Luminal (Phenobarbital) and Dilantin (phenytoin); the antibiotics Rifadin (rifampin), Priftin (rifapentine) and Mycobutin (rifabutin); or products containing St. John’s wort (Hypericum perforatum).
The safety and effectiveness of Intelence in first-time treatment takers has not yet been established. A clinical trial evaluating the benefits of Intelence, as a first-line NNRTI option, is currently under way.
For a more detailed review of the effectiveness of Intelence for the treatment of NNRTI-resistant HIV, check out our recent special report, "Etravirine—Countdown to Launch."