The purpose of this study is to see if it is safe and effective to give ritonavir plus nelfinavir to HIV-infected patients. This study will also see how ritonavir and nelfinavir are absorbed by the body and how they affect the level of HIV in the blood.

• Drug: Ritonavir
• Drug: Nelfinavir mesylate

Inclusion Criteria

Patients must have:

• Documentation of a positive ELISA test for HIV confirmed by immunoblot, or a positive HIV RNA test using the Roche PCR assay, or the Chiron bDNA assay.
• HIV RNA measurement of > 5,000 copies/ml within 3 weeks of baseline visit.
• Signed, informed consent from parent or legal guardian for patients less than 18 years of age.
• Access to a refrigerator for storing study drug.

Prior Medication:

Allowed:

Anti-HIV therapy other than protease inhibitor therapy.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Evidence of acute infection, as measured by vital signs, physical examination, 12-lead electrocardiogram and laboratory assessments.
• Condition that may obscure the proper observation of the safety or activity of the treatment regimens.

Concurrent Medication:

Excluded:

• Midazolam, alprazolam, clorazepate, diazepam, estazolam, flurazepam, triazolam, zolpidem, quinidine, amiodarone, encainide, flecainide, propafenone, bepridil, terfenadine, astemizole, cisapride, bupropion, clozapine, rifabutin, meperidine, propoxyphene, piroxicam, pimozide, ergotamine, dihydroergotamine, and rifampin.
• Anti-retroviral therapy initiated prior to study entry.
• Any other medication, including over-the-counter medicine and alcohol, taken without the permission of the primary investigator.

Patients with the following prior conditions are excluded:

• History of significant drug hypersensitivity.
• History of psychiatric illness that would preclude compliance with the protocol.
• Prior enrollment in this study.

Prior Medication:

Excluded:

• Investigational drugs within 30 days prior to drug administration.

• Prior treatment with licensed or investigational HIV protease inhibitor.

  1. Active substance abuse.

• Positive urine screen for recreational drugs. NOTE:
• The presence of cannabis is not exclusionary unless the investigator believes its use will interfere with patient compliance.