BMS-955176 + atazanavir + ritonavir

BMS-955176 + atazanavir + ritonavir is an investigational three-drug combination evaluated for the treatment of HIV-1 infection. **BMS-955176** is a second-generation small molecule HIV-1 maturation inhibitor that blocks the final cleavage step in the viral Gag polyprotein at the capsid/spacer peptide 1 (CA/SP1) junction, preventing the formation of mature, infectious HIV particles[2][4][6]. **Atazanavir** is a protease inhibitor that blocks HIV-1 protease activity, inhibiting viral maturation. **Ritonavir** is used here as a pharmacokinetic booster for atazanavir, increasing its plasma concentrations by inhibiting cytochrome P450 3A metabolism[1][5]. This combination exploits complementary mechanisms targeting viral maturation and protease function, enabling activity even against viruses resistant to other classes. It has been studied as a NRTI-sparing regimen for adults with HIV-1 subtype B in Phase 2 trials conducted by Bristol Myers Squibb[1]. Main safety concerns include known side effects of atazanavir (notably bilirubin elevations), with boosted atazanavir regimens showing higher bilirubin increases[1][5].