POSITIVELY AWARE MARCH/APRIL 2011
brand name: Epzicom
common name: abacavir sulfate and lamivudine
class: Nucleoside analog reverse transcriptase inhibitor
(nucleoside analog, NRTI, or nuke)—fixed dose combination
manufacturer: ViiV Healthcare | www.viivhealthcare.com, (877) 844-8872
Standard dose: One tablet (600 mg Ziagen/abacavir sulfate/ABC and 300 mg Epivir/lamivudine/3TC), once a day, with or without food, with no dietary restrictions. Take missed dose as soon as possible, unless it is almost time for your next dose. Do not double up on your next dose.
AWP: $1,073.35 / month
Potential side effects and toxicity
The most common side effects of Epzicom are the same as the drugs it contains—see Epivir and Ziagen. Of note is the hypersensitivity reaction (HSR, an allergic-like reaction) warning on Ziagen (abacavir); see Ziagen. A simple and inexpensive blood test for HLA-B*5701 (a genetic marker) can identify people at high risk for this reaction and virtually eliminate HSR. About 90% of HSR occurs within the first six weeks of treatment. Symptoms of HSR usually worsen, very slowly, with every dose. If treatment is stopped because of this serious reaction, you can never take products containing abacavir, such as Epzicom, Trizivir, or Ziagen, again (called “re-challenging”). Rechallenging could cause a rare life-threatening reaction. (This does not apply to missed doses when there’s no HSR, but watch for symptoms if you’ve stopped the drug for at least a few days). Symptoms usually, but not always, include some combination of sudden fever; muscle ache; malaise (general ill feeling); severe nausea, vomiting, diarrhea, or abdominal pain; severe tiredness; respiratory symptoms (cough, difficulty breathing, and sore throat); and possible rash. Symptoms are listed on the patient information sheet and warning card that you receive each time you fill your prescription. You should keep the warning card with you. Hypersensitivity might be confused with flu during flu season, but remember that HSR worsens with every dose. Check with your doctor if you have any side effects after taking this medicine—don’t just stop! Some observational studies seemed to indicate that Ziagen may increase the risk of cardiovascular events, including heart attacks, in people with greater risk factors (such as smoking, diabetes, high blood pressure, and drug use), and that the risk is reversible upon discontinuation. Studies looking into this possible association had mixed results. The available data regarding cardiovascular risk with Ziagen remain inconclusive.
Potential drug interactions
See the drugs contained in Epzicom, Epivir and Ziagen, for more information. Do not take Epzicom with Atripla, Combivir, Emtriva, Epivir, Epivir-HBV, rilpivirine/Truvada, Trizivir, Truvada, or Ziagen, since all or part of these medications are already in Epzicom or have equivalent medications.
More information
Epzicom is the combination of Epivir (lamivudine) and Ziagen (abacavir sulfate) in one tablet, so see the pages for those drugs. Currently, U.S. HIV treatment guidelines re-commend Truvada over Epzicom as the preferred backbone for the NRTI component of an HIV drug combination. Epzicom is listed as an alternative NRTI backbone. Study ACTG 5202 reported that for those people who started treatment with more than 100,000 viral load, Epzicom was “significantly less effective at controlling HIV” in the regimens tested. Moreover, time to a serious adverse event was sooner in the people taking Epzicom. A smaller but newer study (ASSERT) also found less likelihood of reaching undetectable viral load with Epzicom compared to Truvada (all with Sustiva) in people starting HIV treatment for the first time. These efficacy and safety findings were not confirmed in a manufacturer-sponsored study, HEAT, another large study comparing Epzicom and Truvada. Still, in HIV therapy, there is always use for an alternative choice of drugs. The DHHS guidelines state, “Pending additional data, [Epzicom] should be used with caution in individuals who have plasma HIV RNA [viral load] greater than 100,000 copies/mL, as well as in persons at higher risk for cardiovascular disease. However, Epzicom remains a good alternative dual-NRTI option for some treatment-naïve patients.” Remember, too, that Truvada has its own side effect and drug interaction issues, although it’s famed for its tolerability. The HLA-B*5701 test should never be used to diagnose HSR. Do not use a skin patch test to confirm HSR. Regardless of the results, it is important to monitor the potential for this reaction. If HSR is suspected or cannot be ruled out, products containing Ziagen should be discontinued. The incidence of HSR was the same between Epzicom once-daily and Ziagen twice-daily (8% vs. 9%), but the incidence of severe reactions was higher with Epzicom (5% vs. 2%). Remember that the HSR cited may have been suspected, not definitely diagnosed. See package insert for more complete information on potential side effects and interactions.
Doctor’s comments
Epzicom is the safe, well-tolerated, once-daily co-formulation of abacavir and 3TC. It’s generally viewed as the best alternative to Truvada when tenofovir can’t be used (usually for reasons having to do with the kidneys). The issues of abacavir hypersensitivity (see Ziagen) apply to Epzicom as well, so an HLA B*5701 test should always be ordered before taking this drug. Epzicom appears to be somewhat less effective than Truvada in people with viral loads above 100,000. For reasons discussed elsewhere (see Ziagen, page 31), we also tend to avoid Epzicom in people who are at high risk of having coronary heart disease. —Joel Gallant, MD, MPH
Activist’s comments
A combination of Ziagen and Epivir, it was a convenient once-a-day improvement over Combivir. Like with Ziagen, those starting Epzicom should take a test to rule out susceptibility to the hypersensitivity reaction. A more recent concern is the possibility of increased risk of heart disease. The jury is still out, but cautious doctors and patients with other cardiovascular risk factors are avoiding the drug until more data is available. —Jeff Taylor
