Acute, primary HIV infection represents a potentially unique opportunity to eradicate the infection. Although plasma viral load rises rapidly, the dominant infecting virus is relatively uniform genetically, and infection may not be fully established in all tissue sites until some time after exposure. Current antiretroviral therapy is able to reduce plasma viral load to unmeasurable levels in established infection. However, there are many questions that remain about the treatment of primary HIV infection. While it is assumed that aggressive antiretroviral regimens are required, it is not known how long they must be continued. It is hoped that after an interval of aggressive therapy, the number of agents could be safely reduced. This study evaluates if viral suppression can be sustained after study therapy is withdrawn.

Participants in this study will receive lamivudine (3TC), stavudine (d4T), abacavir (ABC), amprenavir (APV), and ritonavir (RTV) for at least 52 weeks. During this induction phase, participants will be followed through regular study visits every 4 or 8 weeks. If the participant's viral load and CD4 counts are within study parameters at the end of 52 weeks, the participant will discontinue all antiretroviral medications simultaneously. Participants in the treatment interruption phase will be followed weekly initially, every 2 weeks for 8 weeks, and then every 4 or 8 weeks. Treatment may be restarted if necessary during this phase based on viral load and CD4 counts. If treatment is restarted, the participant will receive 3TC, d4T, APV, and RTV but not ABC. During this reinduction phase, participants will be followed every 4 or 8 weeks.

Depending on viral load and CD4 counts, participants may be eligible for a second treatment interruption phase following the reinduction phase. Participants will once again stop all antiretroviral medications simultaneously and will have the same monitoring as in the first treatment interruption phase. Following this second treatment interruption, participants will be restarted on 3TC, d4T, APV, and RTV and will be evaluated at Weeks 4, 8, 16, and 24, at which time participants go off study.

The length of study participation for individual participants will vary. The length of each phase will be highly dependent on the participant's laboratory parameters. In general, participants will be enrolled in the study for 3 to 4 years. Participants may also enroll in immunology, compartment, pharmacology, and medication compliance substudies.