Stribild (the Quad) Approved in Canada

On November 26, 2012, Health Canada licensed the sale and use of a new combination of anti-HIV drugs in one pill. This combination has been nicknamed the Quad and will be sold under the brand name Stribild. The combination is a complete treatment regimen; such combinations are called single tablet regimens (STR). Stribild is approved for the treatment of people new to HIV therapy (treatment naive). Stribild is made by the pharmaceutical company Gilead Sciences.

Stribild is already licensed in the U.S. and approval is pending in the European Union and Australia.

Inside the Quad

The Quad contains four medicines, two of which are new, as follows:

• elvitegravir (150 mg) -- this new drug belongs to a class of anti-HIV drugs called integrase inhibitors
• cobicistat (150 mg) -- this new drug is a booster and it does not have anti-HIV activity. Its purpose is to raise and maintain levels of elvitegravir in the blood. Boosters are commonly used in HIV medicine; another example of a booster is the drug ritonavir (Norvir).

The Quad also contains two older anti-HIV medicines that belong to the class commonly called nukes (nucleoside analogues):

• tenofovir (300 mg) -- a popular anti-HIV drug sold under the brand name Viread and found in several combinations including Truvada, Atripla and Complera
• FTC (200 mg) -- found in the same combinations as tenofovir

Stribild is taken once daily with food.

Studies

In clinical trials with treatment-naive HIV-positive people, the Quad has been very effective in reducing the amount of HIV in the blood (viral load) and raising levels of CD4+ T-cells. Together these changes have resulted in improved health. Researchers have found the Quad to be roughly equivalent in effectiveness to another already licensed STR called Atripla, which consists of a fixed-dose combination of the following drugs:

• efavirenz (Sustiva) + tenofovir + FTC

In HIV-positive people who are treatment experienced, researchers found the Quad to be roughly equivalent to a commonly used regimen consisting of the following anti-HIV drugs:

• ritonavir + atazanavir (Reyataz) + tenofovir + FTC

Treatment Issues

In clinical trials, Stribild was generally safe and effective. However, as with any regimen, there are some issues users should be aware of, including the following:

Side Effects

The most common side effects associated with Stribild were nausea and diarrhea. A link to further information about possible side effects and more detailed information from clinical trials appears toward the end of this bulletin.

Kidney and Liver Concerns

Stribild should not be taken by people who have a moderate (or worse) degree of kidney dysfunction. The manufacturer specifies that this refers to people who have an eGFR (estimated glomerular filtration rate) of less than 70. Also, people who have severe liver damage (having Child-Pugh rating of class C) should not use Stribild.

Drug Interactions

The drugs in Stribild, particularly elvitegravir and cobicistat, have the potential to interact with many other drugs and herbs. Always speak to your doctor, nurse and pharmacist about taking other drugs (both prescription and over the counter), supplements or herbs if you are taking Stribild or other anti-HIV medicines.

A drug interaction may do the following:

• It can lower the level of cobicistat or elvitegravir in the blood. This can weaken the effect of Stribild and cause Stribild to fail. If this happens, you may have fewer future treatment options.
• It can raise the level of cobicistat, elvitegravir or other drugs in the blood. This could cause new side effects or make pre-existing side effects worse.