A Randomized, Double-Blind Study of MKC-442 Combined With Viracept in Patients Who Are Epivir + Retrovir Experienced and Are Protease Inhibitor- and Non-Nucleoside Reverse Transcriptase Inhibitor-Naive

In this randomized, placebo-controlled study, patients are allowed to switch at entry to d4T plus 3TC or d4T plus ddI based on investigator and patient preference. Patients are stratified based on the number of nucleoside reverse transcriptase inhibitor (NRTI) treatments that are changed at entry and on screening HIV-1 RNA (obtained within 30 days of entry) as follows: switched 1 NRTI and 10,000-50,000 copies/ml vs switched 1 NRTI and greater than 50,000 copies/ml vs switched 2 NRTIs and 10,000-50,000 copies/ml vs switched 2 NRTIs and greater than 50,000 copies/ml. Patients are randomized within each of these strata to 1 of the following treatment arms:

Arm 1: MKC-442 placebo plus nelfinavir. Arm 2: MKC-442 plus nelfinavir. Arm 3: MKC-442 plus nelfinavir (higher dose). Treatment is administered for 48 weeks. Patients who are considered virologic successes at Week 48 may continue to receive MKC-442 at the discretion of the investigator.