A new update of the U.S. Department of Health and Human Services (DHHS) "Guidelines for the Use of Antiretroviral Agents in HIV-Infected Adults and Adolescents" will make it easier for clinicians and HIV-infected individuals to select an appropriate treatment regimen from among the expanding choices of anti-HIV medications.

Previous versions of the "Guidelines" grouped commonly used antiretroviral agents into columns and asked clinicians to construct a combination regimen by adding drugs from one column with those from another. As the number of available antiretroviral medications has increased, constructing an effective regimen based on this "menu" format has become increasingly difficult.

The new "Guidelines" provide practitioners with a list of suggested combination regimens for the initiation of antiretroviral therapy. Based on results of clinical trials and expert opinion, the suggested regimens are classified as either "preferred" or "alternative."

"With 22 FDA-approved formulations of antiretroviral agents, selecting the right multi-drug combination can be a challenge for even experienced clinicians," explains Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID). "These revised "Guidelines" help simplify the process by which caregivers and patients chart a course of therapy, whether they are receiving antiretroviral treatment for the first time or are treatment-experienced and contemplating a change in drug regimen."

Dr. Fauci and John G. Bartlett, M.D., chief of the Division of Infectious Diseases at the Johns Hopkins University Medical Center, co-chair the Panel on Clinical Practices for the Treatment of HIV Infection, convened by DHHS. The Panel updates the "Guidelines" as new data emerge. First published in 1998, the "Guidelines" have been revised eight times to keep pace with discoveries in the field. With nearly 800,000 visits to the "Guidelines" Web site in 2002, it continues to be a widely used resource.

"As our knowledge and experience with antiretroviral therapies accumulates," says Dr. Bartlett, "it becomes increasingly clear that treatment regimens should be individualized, taking into consideration both the potency of the prescribed regimen and patient-specific factors."

Factors to consider when constructing an individualized antiretroviral regimen listed in the new "Guidelines" include

· Potency and durability of the regimen, as measured by suppression of viral load and improvement in the patient's CD4+ T-cell count;

· Toxicities of the medications, particularly taking into account any underlying medical conditions which may predispose the patient to toxicities;

· Side effects of the medications, especially those which may adversely effect the patient's quality of life;

· Dosing frequency, an important factor in patients' adherence to treatment;

· Pill burden, or the number of pills a patient must take per day, and;

· Potential for drug-drug or food-drug interactions.

The updated "Guidelines" include a new table that lists the advantages and disadvantages of individual components of antiretroviral therapy to aid clinicians in the selection of a treatment regimen. Another new table lists regimens or components that the Panel believes should not be used.

Sections discussing the following special considerations in initiation of therapy have also been added to the "Guidelines":

· Once-daily therapy

· Antiretrovirals not recommended for an initial regimen

· Drug-drug interactions

· Initiating therapy in pregnant women or women who may become pregnant.

The Panel notes that, with more and more patients being treated with antiretroviral therapy for longer periods of time, the incidence of drug resistance continues to increase.

"We have more clinical trial experience and better strategies for managing so-called 'treatment failure' since the last update of the "Guidelines"," says Mark Dybul, M.D., NIAID assistant director for medical affairs and executive secretary of the Panel. "Notably, we have gained more experience in using drug-resistance testing to guide the selection of a new treatment regimen once a patient has failed an initial regimen."

The updated "Guidelines" reflect this new knowledge and experience in a revised section and table on the use of drug-resistance testing in clinical practice. A revised section on the "Management of the Treatment-Experienced Patient" includes new tables that

· Provide guidelines for patient assessment and management based on specific clinical scenarios;

· List novel strategies to consider in patients with few available treatment options, and;

· List treatment options following virologic failure on initial therapy;

"It is important to remember that the "Guidelines" is a living document that represents our best assessment of available evidence at this time," says Dr. Fauci. "With time and additional experience, we hope to provide still better guidance for clinicians and patients with regard to treating HIV/AIDS in the future."

The revised "Guidelines" are available on the HHS AIDSInfo Web site at: http://www.aidsinfo.nih.gov.