The key to successfully combating HIV is to disrupt its replication in the body. HIV replication involves a number of steps, each representing a mechanism that potentially can be targeted by a drug. HAART therapy combines antiretrovirals from at least two different classes of medications, each with the purpose of disrupting the HIV lifecycle by a different mechanism and halting the spread of the virus and destruction of a patient’s immune cells. The higher the efficacy of these combinations, the longer it takes for the virus to mutate and develop resistance to the therapy.

We are focused on expanding upon our successful HIV franchise through the addition of novel drugs that target different mechanisms within the HIV replication cycle. We made progress this year with our leading compound, GS 9137, an integrase inhibitor. Integrase inhibitors are a new and important class of HIV drugs that may, in combination with other antiretrovirals, elicit a rapid reduction in viral load.

In February 2007, we announced the completion of a Phase II clinical trial of GS 9137 boosted with ritonavir. Positive safety and efficacy data were presented at the 14th Conference on Retroviruses and Opportunistic Infections, and the design of our registrational studies is underway.