The war on HIV has taught some important lessons, in particular the need to evaluate clinical results in a larger context. Trials that yield unimpressive results for single drugs may nevertheless indicate good candidates for use in combination therapies. A recent example comes from a relatively new class of antiviral agent, non-nucleoside reverse transcriptase inhibitors (NNRTIs).

NNRTIs act by directly inhibiting the enzyme that converts the HIV RNA genome to DNA, thus preventing integration and viral replication. Other therapies focus on nucleoside analogs such as AZT and 3TC, which bind to a different active site on HIV reverse transcriptase, or HIV protease inhibitors, which block the enzyme responsible for maturation of viral protein