- Are currently receiving one of the following anti-HIV drug combinations: Combivir plus abacavir, Combivir plus abacavir plus a protease inhibitor, or Combivir plus abacavir plus a non-nucleoside reverse transcriptase inhibitor (NNRTI). Patients must have been taking this drug combination for at least the past 16 weeks. This also must be the first anti-HIV drug combination the patient has received.