CASTLE Study Showed Similar Efficacy Between Once-Daily REYATAZ(R) (atazanavir sulfate)/ritonavir and Twice-Daily lopinavir/ritonavir at 48 Weeks in Previously Untreated HIV-Infected Adult Patients

Thursday, February 7, 2008 General News
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PRINCETON, N.J., Feb. 6 Bristol-Myers SquibbCompany (NYSE: BMY) today announced results from the CASTLE study, in which300 mg of once-daily REYATAZ(R) (atazanavir sulfate) taken with 100 mg ofritonavir (REYATAZ/r) showed similar antiviral efficacy to twice-dailylopinavir 400 mg and ritonavir 100 mg (lopinavir/r) in previously untreatedadult HIV-1 infected patients at 48 weeks, as part of HIV combination therapy.In this study, 78 percent of the 440 patients in the REYATAZ/r arm met theprimary endpoint of achieving undetectable viral load (defined as HIV-1 RNAless than 50 copies/mL) at 48 weeks, compared with 76 percent of the 443patients in the lopinavir/r arm.

CASTLE is the first large-scale, open-label, randomized study designed todemonstrate the non-inferiority of REYATAZ/r to lopinavir/r in previouslyuntreated HIV-1 infected adult patients. Data from the CASTLE study werepresented for the first time at the 15th Conference on Retroviruses andOpportunistic Infections (CROI) this week in Boston, Mass.

"The CASTLE study provides important additional data to inform the use ofa once-daily regimen including REYATAZ and ritonavir in antiretroviral-naiveHIV-infected patients," said Jean-Michel Molina, M.D., Hopital Saint Louis,Paris, France. "When choosing a treatment in previously untreated patients itis important to ensure antiviral activity as well as tolerability to optimizethe management of HIV infection over the long term."

The most common grade 2-4 adverse events occurring in greater than orequal to three percent of patients in the once-daily REYATAZ(R) (atazanavirsulfate)/r arm or the twice-daily lopinavir/r arm were diarrhea (two percentand eleven percent, respectively) nausea (four percent and eight percent,respectively), jaundice (four percent and zero percent, respectively) and rash(three percent and two percent, respectively).

The REYATAZ/r arm was associated with significantly lower increases frombaseline compared to the lopinavir/r arm in total cholesterol, triglyceridesand non-HDL cholesterol at 48 weeks (p<0.0001). Two percent of patients inthe REYATAZ/r arm and seven percent of patients in the lopinavir/r armrequired initiation of lipid-lowering therapy in the study.

Safety events in this study were consistent with prior experience. Fourdeaths were reported in each treatment arm at 48 weeks; none were attributedto the study medications. Twelve percent of patients in the REYATAZ/r arm andten percent of patients in the lopinavir/r arm experienced a serious adverseevent.

Nine percent of patients in the REYATAZ/r arm and thirteen percent ofpatients in the lopinavir/r arm discontinued the study therapy before week 48.

About the CASTLE Study

The international, multi-center, open-label, 96-week CASTLE studyrandomized 883 treatment-naive patients infected with HIV-1. Four hundred andforty patients were randomized to receive REYATAZ 300 mg and ritonavir 100 mgonce daily and 443 patients were randomized to receive lopinavir 400 mg andritonavir 100 mg twice daily, each in combination with a once-daily, fixed-dose combination of emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg.All patients had a baseline viral load of greater than or equal to 5,000copies/mL; there was no CD4+ cell count restriction for study entry. Theprimary endpoint for the study was the proportion of patients with viral loadof less than 50 copies/mL at 48 weeks.

Additional Study Results

A number of secondary endpoints were also measured with regard toefficacy, lipid effects, safety and tolerability. Additional study resultsinclude:

Achievement of Undetectable Viral Load in Patients with High BaselineViral Load

A prespecified descriptive analysis of virologic response rates (HIV-1 RNAless than 50 copies/mL) by baseline CD4+ categories (greater than 200cells/mm3, between 100 and


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