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 naïve). 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.
In clinical trials with treatment-naïve 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
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:
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.
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.
In clinical trials with Stribild, about 10% of participants were women. This is less than ideal. Gilead Sciences is committed to conducting further research with Stribild and HIV-positive women. Also, the safety of Stribild in pregnant women is not known.
The long and winding road
Once Health Canada approves a drug, physicians can prescribe it but patients must pay for it unless their private insurance plan provides coverage. HIV/AIDS is a catastrophic disease that can affect people’s ability to work and requires expensive care. In Canada, provincial and territorial ministries of health heavily subsidize the cost of anti-HIV medications. Each ministry has a listing of drugs for which it is prepared to pay. These listings are called formularies.
After federal approval, each HIV medicine must undergo another review process called Common Drug Review (CDR). As part of this review, recommendations are made as to whether the drug in question should be:
- listed on formularies
- listed on formularies with conditions, which means its use is restricted
- not listed at all
The CDR may also result in no decision being made as additional information is gathered. With the exception of Quebec, all provinces and territories, the Departments of National Defence and Veterans Affairs, and the Non-Insured Health Benefits plan participate in the CDR.
Stribild will undergo the CDR process in 2013 with the results available later that year.
Gilead Sciences plans to submit a dossier on Stribild to L'Institut national d'excellence en santé et en services sociaux (INESSS) shortly. Stribild will hopefully be listed on the Quebec formulary - Liste des médicaments assurés du Québec - in 2013.
The wholesale price of Stribild in Canada is approximately $16,600 per person per year; this is considerably less than the wholesale price in the U.S., which is about $28,500 per person per year.
Pharmacies will be able to place orders for Stribild from December 31, 2012, and the company will ship them the drug shortly thereafter.
Quad (Stribild) – safety and effectiveness issues in depth – TreatmentUpdate 191
The Quad (Stribild) and changes to assessments of kidney health – TreatmentUpdate 192
Cobicistat and elvitegravir – safe with methadone or buprenorphine and naloxone – TreatmentUpdate 194
A CATIE Fact Sheet on Stribild is under development.
- Sean R. Hosein
- Rockstroh J, DeJesus E, Henry K, et al. Elvitegravir/cobicistat/emtricitabine/tenofovir DF (Quad) has durable efficacy and differentiated safety compared to atazanavir boosted by ritonavir plus emtricitabine/tenofovir DF at week 96 in treatment-naïve HIV-1-infected patients. In: Program and abstracts of the 11th International Congress on Drug Therapy in HIV Infection, 11–15 November 2012, Glasgow, UK. Abstract 424b.
- Zolopa A, Gallant J, Cohen C, et al. Elvitegravir/cobicistat/emtricitabine/tenofovir DF (Quad) has durable efficacy and differentiated safety compared to efavirenz/emtricitabine/tenofovir DF at week 96 in treatment-naïve HIV-1-infected patients. In: Program and abstracts of the 11th International Congress on Drug Therapy in HIV Infection, 11–15 November 2012, Glasgow, UK. Abstract 424a.
- DeJesus E, Felix J, Vanderwalle B, et al. Indirect treatment comparison of efficacy, safety and resistance of EVG/COBI/FTC/TDF (Quad) vs. RAL + FTC/TDF in treatment-naïve HIV patients. In: Program and abstracts of the 11th International Congress on Drug Therapy in HIV Infection, 11–15 November 2012, Glasgow, UK. Poster 265.
- Lee FJ, Carr A. Tolerability of HIV integrase inhibitors. Current Opinion in HIV/AIDS. 2012 Sep;7(5):422-8.
- Lepist EI, Phan TK, Roy A, et al. Cobicistat boosts the intestinal absorption of transport substrates, including HIV protease inhibitors and GS-7340, in vitro. Antimicrobial Agents and Chemotherapy. 2012 Oct;56(10):5409-13.
- German P, Liu HC, Szwarcberg J, et al. Effect of cobicistat on glomerular filtration rate in subjects with normal and impaired renal function. Journal of Acquired Immune Deficiency Syndromes. 2012 Sep 1;61(1):32-40.