Treatment of HIV Infection
In the early 1980s when the HIV/AIDS epidemic began, people with AIDS were not likely to live longer than a few years. With the development of safe and effective drugs, however, people infected with HIV now have longer and healthier lives.
The discovery and development of new therapeutic strategies against HIV is a high priority for the National Institute of Allergy and Infectious Diseases (NIAID). Research supported by NIAID has already greatly advanced our understanding of HIV and how it causes disease. This knowledge provides the foundation for NIAID's HIV/AIDS research effort and continues to support studies designed to further extend and improve the quality of life of those infected with HIV.
Drugs for HIV/AIDS
Currently, there are 30 antiretroviral drugs approved by the Food and Drug Administration to treat people infected with HIV. These drugs fall into four major classes.
Currently available drugs do not cure HIV infection or AIDS. They can suppress the virus, even to undetectable levels, but they cannot eliminate HIV from the body. Hence, people with HIV need to continuously take antiretroviral drugs.
Highly Actove Antiretroviral Therapy (HAART) Counters Drug Resistance
As HIV reproduces itself, variants of the virus emerge, including some that are resistant to antiretroviral drugs. Therefore, doctors recommend that people infected with HIV take a combination of antiretroviral drugs known as highly active antiretroviral therapy, or HAART. This strategy, which typically combines drugs from at least two different classes of antiretroviral drugs, has been shown to effectively suppress the virus when used properly. Developed by NIAID-supported researchers, HAART has revolutionalized how people infected with HIV are treated. HAART works by suppressing the virus and decreasing the rate of opportunistic infections.
HIV Transmission and Antiretroviral Drugs
Although the use of HAART has greatly reduced the number of deaths due to HIV/AIDS, and possibly the transmission of HIV/AIDS as well, this powerful combination of drugs cannot suppress the virus completely. Therefore, people infected with HIV who take antiretroviral drugs can still transmit HIV to others through unprotected sex and needle-sharing.
Antiretroviral Drug Effects on Opportunistic Infections and AIDS-Associated Co-Infections
People infected with HIV have impaired immune systems that can leave them susceptible to opportunistic infections (OIs) and AIDS-associated co-infections, caused by a wide range of microorganisms such as protozoa, viruses, fungi, and bacteria. One example of an associated co-infection is hepatitis C virus infection, which can lead to liver cancer.
Potent HIV therapies such as HAART, however, have produced dramatic responses in patients. These therapies often allow the immune system to recover, sustain, and protect the body from other infections. Hence, antiretroviral drugs provide a way for the immune system to remain effective, thereby improving the quality and length of life for people with HIV.
Side Effets of Antiretroviral Drugs
People taking antiretroviral drugs may have low adherence to complicated drug regimens. Current recommended regimens involve taking several antiretroviral drugs each day from at least two different classes, some of which may cause unpleasant side effects such as nausea and vomiting. In addition, antiretroviral drugs may cause more serious medical problems, including metabolic changes such as abnormal fat distribution, abnormal lipid and glucose metabolism, and bone loss. Therefore, NIAID is investigating simpler, less toxic, and more effective drug regimens.
Development of New Safe and Effective Antiretroviral Drugs
NIAID supports the development and testing of new therapeutic agents, classes, and combinations of antiretroviral drugs that can continuously suppress the virus with few side effects. Through human clinical trials, NIAID-supported studies provide accurate and extensive information about the safety and efficacy of drug candidates and combinations, and identify potential uncommon but important toxicities of newly approved agents. Studies are also under way to assess rare toxicities of older approved agents, especially as a result of long-term use.
Through the Multicenter AIDS Cohort Study and Women's Interagency HIV Study, NIAID supports long-term studies of HIV disease and its treatment in both men and women. Since their inception, these cohort studies have enrolled and collected data from more than 10,000 people. In addition, NIAID supports treatment studies conducted through three HIV/AIDS clinical trials networks: the AIDS Clinical Trials Group, the International Maternal Pediatric Adolescent AIDS Clinical Trials Group, and the International Network for Strategic Initiatives in Global HIV Trials.
NIAID Research on the Complications of Antiretroviral Drugs
NIAID supports studies aimed at understanding the side effects of antiretroviral drugs as well as strategies to reduce exposure to potentially toxic drug regimens, such as
NIAID also supports projects evaluating regimens containing agents associated with toxicities. For example, NIAID-funded researchers are conducting studies to evaluate treatments for several drug-associated metabolic complications, including fat redistribution, lipid and glucose abnormalities, and bone loss. In addition, researchers are studying the long-term metabolic effects of various antiretroviral regimens in pregnant women and their infants and in HIV-infected children and adolescents.
Down the Road: New Drugs in the Pipeline
The Pharmaceutical Research and Manufacturers Association of America maintains a database of new drugs in development to treat HIV infection. They include new protease inhibitors and more potent, less toxic RT inhibitors, as well as other drugs that interfere with entirely different steps in the virus' lifecycle. These new categories of drugs include
In addition, scientists are exploring whether immune modulators help boost the immune response to the virus and may make existing anti-HIV drugs more effective. Therapeutic vaccines also are being evaluated for this purpose and could help reduce the number of anti-HIV drugs needed or the duration of treatment.
This article was provided by U.S. National Institute of Allergy and Infectious Diseases. It is a part of the publication Understanding HIV/AIDS.