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Controlling HIV: Benefits of Single Tablet Regimen

Advancing Treatment

Treatment for the HIV virus and AIDS — the disease it causes — has come a long way in the last three decades. In the 1980s, HIV was considered a fatal infection. Thanks to advances in treatment, HIV has become more of a chronic condition, much like heart disease or diabetes. A person who is diagnosed today at age 20 can expect to live into their 70s, a nearly full life expectancy.

One of the biggest recent advances in the treatment of HIV/AIDS has been the development of a single-dose medicine — one pill that contains a combination of several different HIV drugs. A combination pill is a big step forward from the cumbersome drug cocktails that used to be the only options for people with HIV/AIDS.

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Treatment History

HIV/AIDS Treatment — From the 1980s to Today

In 1987, the very first drug was approved to treat HIV/AIDS. It was called AZT (short for azidothymidine). AZT is an antiretroviral, a type of drug that helps prevent the HIV virus from copying itself. By lowering the amount of HIV in the body, antiretroviral drugs help a person’s immune system stay strong. AZT is part of a class of antiretroviral drugs called nucleoside reverse transcriptase inhibitors (NRTIs).

The introduction of AZT was a major advancement in HIV/AIDS treatment. But AZT isn’t a perfect drug. At the time, it was the most expensive medicine in history, costing users $8,000 to $10,000 a year ($17,000 to $21,000 a year in today’s dollars). It has significant and potentially serious side effects in some patients. Perhaps most importantly, when used by itself, HIV will eventually become resistant to AZT allowing disease recurrence.

Other HIV drugs followed, including protease inhibitors. These drugs work by stopping the HIV virus from making more viruses inside already-infected cells. Doctors soon discovered that when patients were given only one drug at a time, HIV became resistant to it, making the drug ineffective.

By the end of the 1990s, single drug therapy gave way to combination treatment. This therapy was called highly active antiretroviral therapy (HAART). Now also called combination antiretroviral therapy (cART), HAART uses a “cocktail” of drugs. The drugs come from at least two different drug classes. Effective combination therapy reduces the amount of HIV virus in a person’s body. Combination regimens are designed to both maximize the level of HIV suppression while also minimizing the likelihood of the virus from becoming resistant to any one drug.

Today, multiple different classes of antiretroviral drugs are used in various combinations to treat HIV. All of these drugs interfere with the way the HIV virus copies itself, but in different ways:

  • entry inhibitors and fusion inhibitors: These drugs stop HIV from getting into cells of the immune system in the first place.
  • nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs or “nukes”): NRTIs prevent the virus from copying its genetic material. NRTIs block an enzyme called reverse transcriptase, which HIV uses to copy its genetic material (RNA).
  • non-nucleoside reverse transcriptase inhibitors (NNRTIs or “non-nukes”): NNRTIs also block the virus from copying its genetic material using reverse transcriptase, but they work in a different way than NRTIs.
  • integrase inhibitors: These drugs block an enzyme the virus needs to insert copies of its genes into a human cell’s genetic material (DNA).
  • protease inhibitors: These drugs block an enzyme called protease, which the virus needs to process (cut) proteins that are essential to its ability to make more virus. In the absence of this function, HIV’s ability to replicate is severely limited.
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Single-Pill Therapy

Single-Pill HIV Treatment

In the past, people on HAART needed to take several different pills each day. This complicated regimen often led to mistakes, missed doses and sub-optimal treatment.

Since 2006, fixed-dose combinations of HIV drugs have become available. These drugs combine two or more drugs from the same or different classes. The single, one-dose pill is easier to take.

Currently, four combination tablets are approved to treat HIV:

  • Atripla, which contains efavirenz (NNRTI), emtricitabine (NRTI), and tenofovir disoproxil fumarate (NRTI)
  • Complera, which contains emtricitabine (NRTI), rilpivirine (NNRTI), and tenofovir disoproxil fumarate (NRTI)
  • Stribild, which contains elvitegravir (integrase inhibitor), cobicistat, emtricitabine (NRTI), tenofovir disoproxil fumarate (NRTI)
  • Triumeq, which contains dolutegravir (integrase inhibitor), abacavir (NRTI), lamivudine (NRTI)

One daily pill, instead of three or four, simplifies treatment for people with HIV. It also improves its effectiveness. A study in PLOS ONE found that people who take a single daily pill are less likely to get sick enough to end up in the hospital than those who take three or more daily pills. In addition, fixed-dose combinations cut down on dosing errors. They also lower the likelihood that the HIV virus will become resistant to the treatment.

Yet adding more drugs to one pill can also lead to more side effects, because each drug comes with its own set of risks. If you develop a side effect, it can be hard to tell which of the drugs in the pill caused it.

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Deciding

Choosing Treatment

Choosing an HIV treatment is a very important decision. You should make your decision together with your doctor. Discuss the benefits and risks of single tablets versus a combination pill. Choose the option that best suits your lifestyle and health.

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