Tetracyclic heterocycle compounds useful as HIV integrase inhibitors

A compound having the formula (I):

• wherein:
• R1 is CHR2—O—C(O)—Y—R3, C(O)—C1-C10 alkyl, CHR2—O—P(O)(OH)2 or
• Y is a bond or —O—;
• R2 is hydrogen or C1-C6 alkyl;
• R3 is selected from the group consisting of C1-C6 alkyl, (CH2)x—O—C1-C6 alkyl, and (CH2)x—NR4R5, wherein said C1-C6 alkyl group can be optionally substituted with one to three groups independently selected from the group consisting of halo, hydroxy, methoxy and ethoxy;
• R4 is hydrogen or C1-C6 alkyl;
• R5 is hydrogen or C1-C6 alkyl;
• x is an integer from one to four;
• or a pharmaceutically acceptable salt thereof.