Antiretroviral drugs constitute a milestone in the treatment of human
immunodeficiency virus (HIV) infection; however, emerging problems limit their
long-term use, and an increasing number of patients interrupt the prescribed
continuous drug therapy for short or long periods. Some patients appear to
benefit from structured treatment interruptions (STI), involving monitored
repetition of on-and-off cycles of drugs; however, it is unclear whether patients
and/or physicians should consider STI as a treatment option.
This review is intended to provide a comprehensive update on the use
of STI in clinical settings, and to carefully evaluate the advantages and
potential risks for patients infected with HIV. We used a MEDLINE search to
find all English-language articles published January 1999 to August 2001 regarding
patients treated with highly active antiretroviral therapy for whom treatment
interruption was investigated. Priority was assigned to peer-reviewed sources,
when available. Otherwise, abstracts from authoritative international conferences
were selected through the AIDSLINE database.
Results from various studies with respect to type of drug treatment,
baseline patient status, number of treatment interruptions, duration of treatment
and interruption, changes in viral load, and immune system parameters were
analyzed. Patients could be categorized into 3 distinct clinical scenarios:
acute infection, chronic drug-suppressed infection and virological drug failure.
The STI approach may offer more benefit during acute infection when the patient's
immune system remains nearly intact. It is yet to be determined whether STI
will facilitate the long-term management of chronic infection by decreasing
drug-associated toxicity and improving quality of life without jeopardizing
the efficacy of the treatment. Results from randomized controlled trials and
more definitive means of gauging the status of the patient's immune system
must be available before this treatment method is extended beyond the research
setting. Ultimately, a safer approach using therapeutic immunization or vaccination
would be preferable for stimulating vigorous T-cell–mediated immune
responses and control of HIV during treatment interruption.