For PRAM-1: Evidence supports combination therapy with 2 or more antiviral agents as beneficial in the long-term management of HIV. The possibility exists that combination therapy may result in a synergistic or additive activity over a prolonged period of time. Also hypothesized is that the development of resistance to individual agents will be developed if viral replication is significantly decreased.

AS PER AMENDMENT 10/20/97: For PRAM-1, Step 2: Interim analysis at 12 weeks on PRAM-1 indicates that the proportion of children reaching undetectable RNA levels on the ZDV + 3TC arm is significantly less than the other two arms. The protocol, therefore, has been modified (Step 2) to permit children in the ZDV + 3TC arm with RNA copy number >= 10,000 the opportunity to change to a novel therapeutic regimen (d4T + nevirapine + ritonavir).

The Master PRAM is a Phase II, multicenter, randomized, open-label trial of a standard therapeutic regimen in current use versus experimental therapies administered over 48 weeks. It is designed to allow new therapeutic arms to be studied as "rolling screens" through multiple generations of PRAM. Each PRAM generation compares 2 novel therapeutic arms with a linking arm that allows for an indirect comparison of included therapies. Once accrual to PRAM-1 is complete a new treatment comparison opens for accrual (PRAM-2). The linking arm to be used in PRAM-2 is decided by the Pediatric Primary Scientific Committee. PRAM-2 will continue to accrue patients while PRAM-1 patients continue therapy.

For PRAM-1: This study compares the following three treatment arms:

Arm I: ZDV plus 3TC Arm II: d4T plus ritonavir Arm III: ZDV plus 3TC plus ritonavir. Prior to randomization to one of the three arms, patients are stratified based on CD4 percents: either less than 15% or greater than or equal to 15%. The first 8 patients randomized to Arms II and III participate in a real-time Phase I pharmacokinetic study (16 patients total). After the first 45 (15 per arm) patients entered are followed for 24 weeks, an interim analysis is done. Patients are treated for 48 weeks [AS PER AMENDMENT 1/5/98: 72 weeks].

AS PER AMENDMENT 10/20/97:

PRAM-1, Step 2:

Patients initially assigned to Arm I (ZDV plus 3TC) who have RNA values greater than 10,000 copies at week 12, 24, or 36 are assigned to switch protocol treatment to d4T + ritonavir + nevirapine. Patients may enroll in Step 2 no later than week 38 of PRAM-1. [AS PER AMENDMENT 1/5/98: Patients initially assigned to Arm 1 with viral load greater than 100,000 copies may also switch to Step 2 or discontinue therapy. Patients originally assigned to Arms I or II with viral load greater than 10,000 may continue their current drugs or discontinue study therapy; those with viral load greater than 100,000 should discontinue study drugs.] [AS PER AMENDMENT 7/17/98: PRAM-1 has been extended to permit long-term follow-up of clinically stable, HIV-infected children for a total of 120 weeks. Patients still on initial treatment assignment for all three treatment arms are eligible for this extension, as are children from PRAM-1, Step 2. Step 2 is now closed to enrollment. Patients on 3TC/ZDV who reach virologic failure must discontinue study therapy].

[AS PER AMENDMENT 10/23/98: PRAM-1, Step 3: This amendment substitutes indinavir (IDV) capsules for ritonavir capsules in PRAM-1. The regimens will switch from d4T plus ritonavir versus ZDV plus 3TC plus ritonavir to d4T plus IDV versus ZDV plus 3TC plus IDV. All patients will be followed for 48 weeks. Patients eligible for this change in regimens are those taking ritonavir capsules who have RNA values less than or equal to 10,000 copies/ml (as demonstrated by the most recent viral load test) after at least 72 weeks on PRAM-1, Step I. Twelve patients with RNA values less than or equal to 400 copies/ml will immediately join the study; 6 will receive d4T plus IDV and 6 will receive ZDV plus 3TC plus IDV. Additional patients may be added based on toxicity and viral load results. A total sample size of 53 evaluable patients (37 with RNA values less than or equal to 400 copies/ml and 16 with RNA values of greater than 400 to 10,000 copies/ml) is anticipated. PRAM-1 Step 2 patients are not eligible for Step 3. PRAM-1, Step 2 patients currently taking liquid ritonavir should continue their study drug; those taking ritonavir capsules will switch to liquid ritonavir or go off study.