Merck's Isentress (raltegravir) Tablets in Combination with other Anti-HIV Medicines Maintained Reductions in HIV-1 Viral Load and Increased CD4 Cell Counts Through 48 Weeks of Therapy in Treatment-Experienced Adults

BOSTON--(BUSINESS WIRE)--Feb 6, 2008 - ISENTRESS(R) (raltegravir) tablets, Merck's HIV integrase inhibitor, in combination with other anti-HIV medicines, maintained significant HIV-1 viral load suppression and increased CD4 cell counts through 48 weeks of therapy compared to placebo in combination with anti-HIV medicines, in two Phase III studies of 699 treatment-experienced patients failing antiretroviral therapies (ARTs). Patients in the studies had HIV resistant to at least one drug in each of three classes (nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs)) of oral antiretroviral medicines.

In October, the U.S. Food and Drug Administration (FDA) granted ISENTRESS accelerated approval for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced adult patients with evidence of viral replication with HIV-1 strains resistant to multiple antiretroviral agents. The approval was based on analyses of viral load reductions and CD4 cell count increases from baseline through 24 weeks in two phase III studies of ISENTRESS. This week, 48-week data from those same studies were presented at the 15th Conference on Retroviruses and Opportunistic Infections (CROI).

The use of other active agents with ISENTRESS is associated with a greater likelihood of treatment response. The safety and efficacy of ISENTRESS have not been established in treatment-naive adult patients or pediatric patients. There are no study results demonstrating the effect of ISENTRESS on clinical progression of HIV-1 infection.

"The 48-week efficacy results are consistent with what we observed at Week 24," said Roy Steigbigel M.D., professor of medicine, pathology, microbiology and pharmacology, State University of New York at Stony Brook and lead study investigator for one of the studies.

ISENTRESS studied in nearly 700 patients

The data presented this week are from Week 48 results from two identical ongoing multi-center, double-blind, randomized, placebo-controlled Phase III studies (BENCHMRK-1 and BENCHMRK-2) that compare ISENTRESS in combination with optimized background therapy (OBT) to placebo plus OBT. The primary endpoint of this ongoing study is the percentage of patients in each study arm that achieve HIV RNA viral levels less than 400 copies/mL at Week 16. Patients in BENCHMRK-1 were enrolled in Europe, Asia/Pacific and Peru. The mean baseline viral load was 4.6 log10 copies/mL for the regimen with ISENTRESS and 4.5 log10 copies/mL for the placebo regimen, respectively. The median baseline CD4 cell counts were 140 cells/mm(3) for the regimen with ISENTRESS and 105 cells/mm(3) for the placebo regimen, respectively. Patients in BENCHMRK-2 were enrolled in North and South America. The mean baseline viral load was 4.7 log10 copies/mL for both the regimen with ISENTRESS and the placebo regimen, respectively. The median baseline CD4 cell counts were 102 cells/mm(3) for the regimen with ISENTRESS and 132 cells/mm(3) for the placebo regimen, respectively.

Patients who entered the study experienced treatment failure on prior antiretroviral therapies and were infected with HIV resistant to one or more drugs in each of three oral classes of ARTs (NRTIs, NNRTIs and PIs).

Patients received ISENTRESS 400 mg or placebo, each dosed orally twice daily in combination with OBT. OBT was determined based on patients' prior treatment history and results from HIV resistance testing. In order to allow for the best possible treatment regimen to be constructed for each patient, darunavir and tipranavir, which were investigational medicines in many countries at the time of this study, were allowed to be included in OBT.

Suppression of viral load and increases in CD4 cell counts observed through 48 weeks

In one of these studies, called BENCHMRK-1, at 48 weeks, ISENTRESS plus OBT maintained suppression of HIV RNA levels below 400 copies/mL in 74 percent of patients (170 out of 231) compared to 36 percent of patients (43 out of 118) receiving placebo plus OBT; p<0.001. In the companion study, BENCHMRK-2, ISENTRESS plus OBT suppressed viral loads below 400 copies/mL in 71 percent of patients (162 out of 228) compared to 38 percent of patients (45 out of 119) receiving placebo plus OBT; p<0.001.

In addition, in BENCHMRK-1, after 48 weeks of therapy, ISENTRESS plus OBT suppressed viral load to below 50 copies/mL in 65 percent of patients (149 out of 231) compared to 31 percent of patients (37 out of 118) who received placebo plus OBT; p<0.001. ISENTRESS plus OBT increased CD4 cell counts from baseline by 120 cells/mm(3) compared to 49 cells/mm(3) for patients receiving placebo plus OBT; p<0.001. In BENCHMRK-2 after 48 weeks, 60 percent of patients (136 out of 228) receiving ISENTRESS plus OBT achieved viral loads below 50 copies/mL compared to 34 percent of patients (41 out of 119) receiving placebo plus OBT; p<0.001. ISENTRESS plus OBT increased CD4 cell counts from baseline by 98 cells/mm(3) compared to 40 cells/mm(3) for those patients receiving placebo plus OBT; p<0.001.

After 48 weeks of therapy, in BENCHMRK-1, 4 of 232 patients (1.7 percent) receiving ISENTRESS plus OBT and 4 of 118 patients (3.4 percent) receiving placebo plus OBT discontinued therapy due to adverse experiences. In addition, 7 of 232 patients (3.0 percent) receiving ISENTRESS plus OBT and 1 of 118 patients (0.8 percent) receiving placebo plus OBT experienced a serious drug-related adverse event. The most commonly reported (reported in at least two percent of patients) study therapy-related side effects in patients receiving raltegravir plus OBT were diarrhea, nausea, vomiting, fatigue, injection site pain or reaction (due to enfuvirtide), joint pain, headache and itching.

In BENCHMRK-2, 7 of 230 patients (3.0 percent) receiving ISENTRESS plus OBT and 3 of 119 patients (2.5 percent) receiving placebo plus OBT discontinued therapy. In addition, 4 of 230 patients (1.7 percent) receiving ISENTRESS plus OBT and 6 of 119 patients (5.0 percent) receiving placebo plus OBT experienced a serious drug-related adverse event. The most commonly reported (reported in at least two percent of patients) study therapy-related side effects in patients receiving raltegravir plus OBT were bloating, abdominal pain, constipation, diarrhea, gas, nausea, vomiting, fatigue, injection site reaction (due to enfuvirtide), dizziness and headache.

"The results show that after 48 weeks ISENTRESS in combination with other anti-HIV medicines continued to provide significantly greater antiretroviral activity and increases in CD4 cells compared to placebo with other antiretroviral medicines," said David Cooper M.D., D.Sc., professor of medicine and director of the National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia.

Important safety information about ISENTRESS

ISENTRESS does not cure HIV or AIDS and does not prevent passing HIV to others. Healthcare providers should know that immune reconstitution syndrome has been reported in patients treated with antiretroviral therapy, which may necessitate further evaluation and treatment.

At 24 weeks, the most commonly reported adverse experiences of any severity (mild, moderate or severe) for ISENTRESS plus OBT versus placebo plus OBT, respectively, regardless of drug relationship were diarrhea (16.6 percent vs. 19.5 percent), nausea (9.9 percent vs. 14.2 percent), headache (9.7 percent vs. 11.7 percent) and fever (4.9 percent vs. 10.3 percent).

Creatine kinase elevations were observed in subjects who received ISENTRESS. Myopathy and rhabdomyolysis have been reported; however, the relationship of ISENTRESS to these events is not known. ISENTRESS should be used with caution in patients at increased risk of myopathy or rhabdomyolysis, such as patients receiving concomitant medication known to cause these conditions.

Results from pooled safety analyses from three separate studies (BENCHMRK-1, BENCHMRK-2 and a Phase II dose ranging study) in treatment-experienced patients taking 400 mg of ISENTRESS dosed twice daily plus OBT or placebo plus OBT showed that after 24 weeks of therapy the rates of discontinuation of therapy due to adverse experiences were 2.0 percent in patients receiving ISENTRESS plus OBT and 1.4 percent in patients receiving placebo plus OBT. In addition, drug-related clinical adverse events of moderate to severe intensity occurring in greater than or equal to 2.0 percent of patients were diarrhea (3.7 percent vs. 4.6 percent), nausea (2.2 percent vs. 3.2 percent) and headache (2.4 percent vs. 1.4 percent) for ISENTRESS plus OBT and placebo plus OBT, respectively.

Drug interactions

Based on the results of drug interaction studies and the clinical trials data, no dose adjustment of ISENTRESS is required when coadministered with other antiretroviral agents. Preclinical studies showed that ISENTRESS is not metabolized by cytochrome P450 enzymes, but is primarily metabolized by uridine diphosphate glucuronosyltransferase (UGT) 1A1; therefore, caution should be used when coadministering ISENTRESS with strong inducers of UGT 1A1 (e.g., rifampin), which may reduce plasma concentrations of ISENTRESS.

About ISENTRESS

ISENTRESS is a single 400 mg tablet taken twice daily without regard to food. ISENTRESS does not require boosting with ritonavir.

ISENTRESS is the first medicine to be approved in a new class of antiretroviral drugs called integrase inhibitors. ISENTRESS works by inhibiting the insertion of HIV-1 DNA into human DNA by the integrase enzyme. Inhibiting integrase from performing this essential function limits the ability of the virus to replicate and infect new cells. There are drugs in use that inhibit two other enzymes critical to the HIV-1 replication process - protease and reverse transcriptase - but ISENTRESS is the only drug approved that inhibits the integrase enzyme.

Merck HIV Research

Merck is committed to developing innovative therapies that offer advances in the treatment of infectious diseases - including HIV. Merck's efforts to develop investigational treatments for HIV and AIDS have been under way for more than 20 years and continue today. Merck began its HIV integrase inhibitor research in 1993 and was the first to demonstrate inhibition of HIV integrase in vitro and in vivo.

Prevalence of HIV and AIDS

In 2006, more than one million Americans were living with HIV and AIDS and it is estimated that approximately 40,000 new cases of HIV and AIDS are diagnosed each year in the United States.

Worldwide, an estimated 33 million people are infected with HIV and AIDS, and more than two million new infections occurred in 2007.

About Merck

Merck & Co., Inc. is a global research-driven pharmaceutical company dedicated to putting patients first. Established in 1891, Merck currently discovers, develops, manufactures and markets vaccines and medicines to address unmet medical needs. The Company devotes extensive efforts to increase access to medicines through far-reaching programs that not only donate Merck medicines but help deliver them to the people who need them. Merck also publishes unbiased health information as a not-for-profit service. For more information, visit www.merck.com.

Forward-looking statement

This press release contains "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements are based on management's current expectations and involve risks and uncertainties, which may cause results to differ materially from those set forth in the statements. The forward-looking statements may include statements regarding product development, product potential or financial performance. No forward-looking statement can be guaranteed, and actual results may differ materially from those projected. Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise. Forward-looking statements in this press release should be evaluated together with the many uncertainties that affect Merck's business, particularly those mentioned in the risk factors and cautionary statements in Item 1A of Merck's Form 10-K for the year ended Dec. 31, 2006, and in its periodic reports on Form 10-Q and Form 8-K, which the company incorporates by reference.

ISENTRESS(R) is a registered trademark of Merck & Co., Inc. All other brands are trademarks of their respective owners and are not trademarks of Merck & Co., Inc.

Full prescribing information and patient product information for ISENTRESS is attached.

HIGHLIGHTS OF PRESCRIBING INFORMATION

These highlights do not include all the information needed to use ISENTRESS safely and effectively. See full prescribing information for ISENTRESS.

ISENTRESS (raltegravir) Tablets

Initial U.S. Approval: 2007

INDICATIONS AND USAGE

ISENTRESS(TM) is a human immunodeficiency virus integrase strand transfer inhibitor (HIV-1 INSTI) indicated:

-- In combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced adult patients who have evidence of viral replication and HIV-1 strains resistant to multiple antiretroviral agents (1).

The safety and efficacy of ISENTRESS have not been established in treatment-naive adult patients or pediatric patients (1).

DOSAGE AND ADMINISTRATION

-- 400 mg administered orally, twice daily with or without food (2.1).

DOSAGE FORMS AND STRENGTHS

Tablets: 400 mg (3).

CONTRAINDICATIONS

None

WARNINGS AND PRECAUTIONS

Monitor for Immune Reconstitution Syndrome (5.1)

Drug Interactions

-- Caution should be used when coadministering ISENTRESS with strong inducers of uridine diphosphate glucuronosyltransferase (UGT) 1A1 (e.g., rifampin) due to reduced plasma concentrations of raltegravir (5.2).

ADVERSE REACTIONS

-- The most common adverse reactions (>10%) of all intensities, reported in subjects in either the ISENTRESS or the placebo treatment group, regardless of causality were: nausea, headache, diarrhea and pyrexia (6.1).

-- Creatine kinase elevations were observed in subjects who received ISENTRESS. Myopathy and rhabdomyolysis have been reported; however, the relationship of ISENTRESS to these events is not known. Use with caution in patients at increased risk of myopathy or rhabdomyolysis, such as patients receiving concomitant medications known to cause these conditions (6.1).

To report SUSPECTED ADVERSE REACTIONS, contact Merck & Co., Inc. at 1-877-888-4231 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

USE IN SPECIFIC POPULATIONS

Pregnancy:

-- ISENTRESS should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Physicians are encouraged to register pregnant women exposed to ISENTRESS by calling 1-800-258-4263 so that Merck can monitor maternal and fetal outcomes (8.1).

Nursing Mothers:

-- Breast-feeding is not recommended while taking ISENTRESS (8.3).

See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling.

Revised: 10/2007

FULL PRESCRIBING INFORMATION: CONTENTS*

1 INDICATIONS AND USAGE

2 DOSAGE AND ADMINISTRATION

2.1 Dosing Information

3 DOSAGE FORMS AND STRENGTHS

4 CONTRAINDICATIONS

5 WARNINGS AND PRECAUTIONS

5.1 Immune Reconstitution Syndrome

5.2 Drug Interactions

6 ADVERSE REACTIONS

6.1 Clinical Trials Experience

7 DRUG INTERACTIONS

7.1 Effect of Raltegravir on the Pharmacokinetics of Other Agents

7.2 Effect of Other Agents on the Pharmacokinetics of Raltegravir

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

8.3 Nursing Mothers

8.4 Pediatric Use

8.5 Geriatric Use

8.6 Use in Patients with Hepatic Impairment

8.7 Use in Patients with Renal Impairment

10 OVERDOSAGE

11 DESCRIPTION

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

12.2 Pharmacodynamics

12.3 Pharmacokinetics

12.4 Microbiology

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

14 CLINICAL STUDIES

16 HOW SUPPLIED/STORAGE AND HANDLING

17 PATIENT COUNSELING INFORMATION

*Sections or subsections omitted from the Full Prescribing Information are not listed.

FULL PRESCRIBING INFORMATION

1 INDICATIONS AND USAGE

ISENTRESS(1) in combination with other antiretroviral agents is indicated for the treatment of HIV-1 infection in treatment-experienced adult patients who have evidence of viral replication and HIV-1 strains resistant to multiple antiretroviral agents.

This indication is based on analyses of plasma HIV-1 RNA levels up through 24 weeks in two controlled studies of ISENTRESS. These studies were conducted in clinically advanced, 3-class antiretroviral (NNRTI, NRTI, PI) treatment-experienced adults.

The use of other active agents with ISENTRESS is associated with a greater likelihood of treatment response (see Clinical Studies (14)).

The safety and efficacy of ISENTRESS have not been established in treatment-naive adult patients or pediatric patients.

There are no study results demonstrating the effect of ISENTRESS on clinical progression of HIV-1 infection.

2 DOSAGE AND ADMINISTRATION

2.1 Dosing Information

For the treatment of patients with HIV-1 infection, the dosage of ISENTRESS is 400 mg administered orally, twice daily with or without food.

3 DOSAGE FORMS AND STRENGTHS

400 mg pink, oval-shaped, film-coated tablets with "227" on one side.

4 CONTRAINDICATIONS

None

5 WARNINGS AND PRECAUTIONS

5.1 Immune Reconstitution Syndrome

During the initial phase of treatment, patients responding to antiretroviral therapy may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium complex, cytomegalovirus, Pneumocystis jiroveci pneumonia, Mycobacterium tuberculosis, or reactivation of varicella zoster virus), which may necessitate further evaluation and treatment.

5.2 Drug Interactions

Caution should be used when coadministering ISENTRESS with strong inducers of uridine diphosphate glucuronosyltransferase (UGT) 1A1 (e.g., rifampin) due to reduced plasma concentrations of raltegravir (see Drug Interactions (7)).

6 ADVERSE REACTIONS

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Treatment-Experienced Studies

The safety assessment of ISENTRESS in treatment-experienced subjects is based on the pooled safety data from the randomized, double-blind, placebo-controlled trials, BENCHMRK 1 and BENCHMRK 2 (Protocols 018 and 019), and the randomized, double-blind, placebo-controlled, dose-ranging trial (Protocol 005) in antiretroviral treatment-experienced HIV-1 infected adult subjects reported using the recommended dose of ISENTRESS 400 mg twice daily in combination with optimized background therapy (OBT) in 507 subjects, in comparison to 282 subjects taking placebo in combination with OBT. During double-blind treatment, the total follow-up was 332.2 patient-years in the ISENTRESS 400 mg twice daily group and 150.2 patient-years in the placebo group.

The most commonly (>10%) reported adverse reactions, of all intensities, regardless of causality in subjects treated with ISENTRESS and OBT versus placebo and OBT are presented in Table 1. -0-

   Table 1: Percentage of Subjects with the Most Commonly Reported

    (>10%) Adverse Reactions of All Intensities* and Regardless of

                        Causality Occurring in


                 Treatment-Experienced Adult Subjects


                                                   Randomized Studies

                                                  P005, P018 and P019

     System Organ Class, Adverse Reactions         ISENTRESS  Placebo

                                                    400 mg     + OBT

                                                  twice daily (n=282)+

                                                     + OBT       %

                                                   (n=507)+

                                                       %

Gastrointestinal Disorders

----------------------------------------------------------------------

Diarrhea                                                 16.6     19.5

------------------------------------------------- ----------- --------

Nausea                                                    9.9     14.2

------------------------------------------------- ----------- --------

Nervous System Disorders

------------------------------------------------- ----------- --------

Headache                                                  9.7     11.7

------------------------------------------------- ----------- --------

General Disorders and Administration Site Conditions

----------------------------------------------------------------------

Pyrexia                                                   4.9     10.3

------------------------------------------------- ----------- --------

*Intensities are defined as follows: Mild (awareness of sign or symptom, but easily tolerated); Moderate (discomfort enough to cause interference with usual activity); Severe (incapacitating with inability to work or do usual activity).

+n=total number of subjects per treatment group.

The clinical adverse reactions listed below were considered by investigators to be of moderate to severe intensity and causally related to any drug in the combination regimen (ISENTRESS/placebo alone or in combination with OBT, or OBT alone):

Common Adverse Reactions

Drug-related clinical adverse reactions of moderate to severe intensity occurring in =>2% of subjects treated with ISENTRESS + OBT are presented in Table 2. -0-

      Table 2: Percentage of Subjects with Drug-Related* Adverse

   Reactions of Moderate to Severe Intensity+ Occurring in =>2% of

                 Treatment-Experienced Adult Subjects


                                                   Randomized Studies

                                                          P005,

                                                      P018 and P019

                                                   -------------------

System Organ Class, Adverse Reactions              ISENTRESS

                                                      400 mg   Placebo

                                                   Twice Daily  + OBT

                                                      + OBT     (n =

                                                   (n = 507)++ 282)++

                                                        %         %

Gastrointestinal Disorders

----------------------------------------------------------------------

Diarrhea                                                   3.7     4.6

-------------------------------------------------- ----------- -------

Nausea                                                     2.2     3.2

-------------------------------------------------- ----------- -------

Nervous System Disorders

----------------------------------------------------------------------

Headache                                                   2.4     1.4

-------------------------------------------------- ----------- -------

*Includes adverse reactions at least possibly, probably, or very likely related to the drug.

+Intensities are defined as follows: Moderate (discomfort enough to cause interference with usual activity); Severe (incapacitating with inability to work or do usual activity).

++n=total number of subjects per treatment group.

Less Common Adverse Reactions

Drug-related adverse reactions occurring in at least 1% but less than 2% of treatment-experienced subjects (n=507) receiving ISENTRESS + OBT and of moderate (discomfort enough to cause interference with usual activity) to severe (incapacitating with inability to work or do usual activity) intensity are listed below by system organ class:

Gastrointestinal Disorders: abdominal pain, vomiting

General Disorders and Administration Site Conditions: asthenia, fatigue

Nervous System Disorders: dizziness

Skin and Subcutaneous Tissue Disorders: lipodystrophy acquired

Discontinuations

In the pooled analyses for studies P005, P018 and P019, the rates of discontinuation of therapy due to adverse reactions were 2.0% in subjects receiving ISENTRESS + OBT and 1.4% in subjects receiving placebo + OBT.

Serious Events

Drug Related

The following serious drug-related reactions were reported in the clinical studies, P005, P018 and P019: hypersensitivity (hypersensitivity was seen in 2 subjects with ISENTRESS; therapy was interrupted and upon rechallenge the subjects were able to resume drug), anemia, neutropenia, myocardial infarction, gastritis, hepatitis, herpes simplex, toxic nephropathy, renal failure, chronic renal failure and renal tubular necrosis.

Regardless of Drug Relationship

Cancers were reported in treatment-experienced subjects who initiated ISENTRESS with OBT; several were recurrent. The types and rates of specific cancers were those expected in a highly immunodeficient population (many had CD4+ cell counts below 50 cells/mm(3) and most had prior AIDS diagnoses). The cancers included Kaposi's sarcoma, lymphoma, squamous cell carcinoma, hepatocellular carcinoma and anal cancer. Most subjects had other risk factors for cancer including tobacco use, papillomavirus and active hepatitis B virus infection. It is unknown if these cancer diagnoses were related to ISENTRESS use.

Grade 2-4 creatine kinase laboratory abnormalities were observed in subjects treated with ISENTRESS (see Table 3). Myopathy and rhabdomyolysis have been reported; however, the relationship of ISENTRESS to these events is not known. Use with caution in patients at increased risk of myopathy or rhabdomyolysis, such as patients receiving concomitant medications known to cause these conditions.

Patients with Co-existing Conditions

Patients Co-infected with Hepatitis B and/or Hepatitis C Virus

In the clinical studies, P018 and P019, subjects with chronic (but not acute) active hepatitis B and/or hepatitis C virus co-infection (N = 113/699 or 16.2%) were permitted to enroll provided that baseline liver function tests did not exceed 5 times the upper limit of normal (ULN). The rates of AST and ALT abnormalities were somewhat higher in the subgroup of subjects with hepatitis B and/or hepatitis C virus co-infection for both treatment groups. In general the safety profile of ISENTRESS in subjects with hepatitis B and/or hepatitis C virus co-infection was similar to subjects without hepatitis B and/or hepatitis C virus co-infection. Grade 2 or higher laboratory abnormalities that represent a worsening from baseline of AST, ALT or total bilirubin occurred in 26%, 27% and 12%, respectively, of raltegravir-treated coinfected subjects as compared to 9%, 8% and 7% of all other raltegravir-treated subjects.

Laboratory Abnormalities

The percentages of adult subjects treated with ISENTRESS 400 mg twice daily in P005, P018 and P019 with selected Grades 2 to 4 laboratory abnormalities that represent a worsening from baseline are presented in Table 3. -0-

   Table 3: Selected Grade 2 to 4 Laboratory Abnormalities Reported

                  in Treatment-Experienced Subjects

                                                        Randomized

                                                       Studies P005,

                                                       P018 and P019

                                                     ISENTRESS Placebo

                                                        400 mg     +

 Laboratory Parameter Preferred Term       Limit        Twice     OBT

                (Unit)                                 Daily +    (N =

                                                         OBT      282)

                                                      (N = 507)

-------------------------------------- -------------------------------

Hematology

-------------------------------------- -------------------------------

Absolute neutrophil count (103/

(mu)L)

                Grade 2                 0.75 - 0.999         3.7% 7.4%

                Grade 3                 0.50 - 0.749         2.4% 2.5%

                Grade 4                         0.50         1.0% 1.1%

-------------------------------------- -------------------------------

Hemoglobin (gm/dL)

                Grade 2                    7.5 - 8.4         1.0% 2.8%

                Grade 3                    6.5 - 7.4         1.0% 0.4%

                Grade 4                          6.5         0.0% 0.0%

-------------------------------------- -------------------------------

Platelet count (103/(mu)L)

                Grade 2                  50 - 99.999         3.7% 5.7%

                Grade 3                  25 - 49.999         0.4% 0.4%

                Grade 4                           25         0.8% 0.4%

-------------------------------------- -------------------------------

Blood chemistry

-------------------------------------- -------------------------------

Fasting (non-random) serum glucose

 test

 (mg/dL)

                Grade 2                    126 - 250         9.3% 6.8%

                Grade 3                    251 - 500         1.4% 1.4%

                Grade 4                     >500             0.0% 0.0%

-------------------------------------- -------------------------------

Total serum bilirubin

                Grade 2                 1.6 - 2.5 x

                                             ULN             5.3% 6.7%

                Grade 3                 2.6 - 5.0 x

                                             ULN             3.2% 2.5%

                Grade 4                  >5.0 x ULN          0.8% 0.0%

-------------------------------------- -------------------------------

Serum aspartate aminotransferase

                Grade 2                 2.6 - 5.0 x

                                             ULN             9.1% 5.7%

                Grade 3                 5.1 - 10.0 x

                                             ULN             2.2% 2.1%

                Grade 4                 >10.0 x ULN          0.4% 0.7%

-------------------------------------- -------------------------------

Serum alanine aminotransferase

                Grade 2                 2.6 - 5.0 x

                                             ULN             6.9% 7.8%

                Grade 3                 5.1 - 10.0 x

                                             ULN             3.0% 1.4%

                Grade 4                 >10.0 x ULN          0.6% 1.1%

-------------------------------------- -------------------------------

Serum alkaline phosphatase

                Grade 2                 2.6 - 5.0 x

                                             ULN             2.0% 0.4%

                Grade 3                 5.1 - 10.0 x

                                             ULN             0.4% 1.1%

                Grade 4                 >10.0 x ULN          0.4% 0.4%

-------------------------------------- -------------------------------

Serum pancreatic amylase test

                Grade 2                 1.6 - 2.0 x

                                             ULN             1.4% 0.7%

                Grade 3                 2.1 - 5.0 x

                                             ULN             3.6% 2.1%

                Grade 4                  >5.0 x ULN          0.2% 0.0%

-------------------------------------- -------------------------------

Serum lipase test

                Grade 2                 1.6 - 3.0 x

                                             ULN             3.4% 1.8%

                Grade 3                 3.1 - 5.0 x

                                             ULN             0.6% 0.4%

                Grade 4                  >5.0 x ULN          0.2% 0.0%

-------------------------------------- -------------------------------

Serum creatine kinase

                Grade 2                 6.0 - 9.9 x

                                             ULN             2.2% 1.4%

                Grade 3                  10.0 - 19.9

                                            x ULN            2.4% 1.8%

                Grade 4                 =>20.0 x ULN         2.2% 0.7%

-------------------------------------- -------------------------------

ULN = Upper limit of normal range

7 DRUG INTERACTIONS

7.1 Effect of Raltegravir on the Pharmacokinetics of Other Agents

Raltegravir does not inhibit (IC50>100 uM) CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 or CYP3A in vitro. Moreover, in vitro, raltegravir did not induce CYP3A4. A midazolam drug interaction study confirmed the low propensity of raltegravir to alter the pharmacokinetics of agents metabolized by CYP3A4 in vivo by demonstrating a lack of effect of raltegravir on the pharmacokinetics of midazolam, a sensitive CYP3A4 substrate. Similarly, raltegravir is not an inhibitor (IC50>50 uM) of the UDP-glucuronosyltransferases (UGT) tested (UGT1A1, UGT2B7), and raltegravir does not inhibit P-glycoprotein-mediated transport. Based on these data, ISENTRESS is not expected to affect the pharmacokinetics of drugs that are substrates of these enzymes or P-glycoprotein (e.g., protease inhibitors, NNRTIs, methadone, opioid analgesics, statins, azole antifungals, proton pump inhibitors, oral contraceptives, and anti-erectile dysfunction agents).

In drug interaction studies, raltegravir did not have a clinically meaningful effect on the pharmacokinetics of the following: lamivudine, tenofovir.

7.2 Effect of Other Agents on the Pharmacokinetics of Raltegravir

Raltegravir is not a substrate of cytochrome P450 (CYP) enzymes. Based on in vivo and in vitro studies, raltegravir is eliminated mainly by metabolism via a UGT1A1-mediated glucuronidation pathway.

Rifampin, a strong inducer of UGT1A1, reduces plasma concentrations of ISENTRESS. Therefore, caution should be used when coadministering ISENTRESS with rifampin or other strong inducers of UGT1A1 (see Warnings and Precautions (5.2)). The impact of other inducers of drug metabolizing enzymes, such as phenytoin and phenobarbital, on UGT1A1 is unknown. Other less strong inducers (e.g., efavirenz, nevirapine, rifabutin, St. John's wort) may be used with the recommended dose of ISENTRESS.

Similar to rifampin, tipranavir/ritonavir reduces plasma concentrations of ISENTRESS. However, approximately 100 subjects received raltegravir in combination with tipranavir/ritonavir in Protocols 018 and 019. Comparable efficacy was observed in this subgroup relative to subjects not receiving tipranavir/ritonavir. Based on these data, tipranavir/ritonavir may be coadministered with ISENTRESS without dose adjustment of ISENTRESS.

Atazanavir, a strong inhibitor of UGT1A1, and atazanavir/ritonavir increase plasma concentrations of raltegravir. However, concomitant use of ISENTRESS and atazanavir/ritonavir did not result in a unique safety signal in Protocol 005 and Protocols 018 and 019. Based on these data, atazanavir/ritonavir may be coadministered with ISENTRESS without dose adjustment of ISENTRESS.

Coadministration of ISENTRESS with other drugs that inhibit UGT1A1 may increase plasma levels of raltegravir.

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Pregnancy Category C

ISENTRESS should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There are no adequate and well-controlled studies in pregnant women. In addition, there have been no pharmacokinetic studies conducted in pregnant patients.

Developmental toxicity studies were performed in rabbits (at oral doses up to 1000 mg/kg/day) and rats (at oral doses up to 600 mg/kg/day). The reproductive toxicity study in rats was performed with pre-, peri-, and postnatal evaluation. The highest doses in these studies produced systemic exposures in these species approximately 3- to 4-fold the exposure at the recommended human dose. In both rabbits and rats, no treatment-related effects on embryonic/fetal survival or fetal weights were observed. In addition, no treatment-related external, visceral, or skeletal changes were observed in rabbits. However, treatment-related increases over controls in the incidence of supernumerary ribs were seen in rats at 600 mg/kg/day (exposures 3-fold the exposure at the recommended human dose).

Placenta transfer of drug was demonstrated in both rats and rabbits. At a maternal dose of 600 mg/kg/day in rats, mean drug concentrations in fetal plasma were approximately 1.5- to 2.5-fold greater than in maternal plasma at 1 hour and 24 hours postdose, respectively. Mean drug concentrations in fetal plasma were approximately 2% of the mean maternal concentration at both 1 and 24 hours postdose at a maternal dose of 1000 mg/kg/day in rabbits.

Antiretroviral Pregnancy Registry

To monitor maternal-fetal outcomes of pregnant patients exposed to ISENTRESS, an Antiretroviral Pregnancy Registry has been established. Physicians are encouraged to register patients by calling 1-800-258-4263.

8.3 Nursing Mothers

Breast-feeding is not recommended while taking ISENTRESS. In addition, it is recommended that HIV-infected mothers not breast-feed their infants to avoid risking postnatal transmission of HIV.

It is not known whether raltegravir is secreted in human milk. However, raltegravir is secreted in the milk of lactating rats. Mean drug concentrations in milk were approximately 3-fold greater than those in maternal plasma at a maternal dose of 600 mg/kg/day in rats. There were no effects in rat offspring attributable to exposure of ISENTRESS through the milk.

8.4 Pediatric Use

Safety and effectiveness of ISENTRESS in pediatric patients less than 16 years of age have not been established.

8.5 Geriatric Use

Clinical studies of ISENTRESS did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Use in Patients with Hepatic Impairment

No clinically important pharmacokinetic differences between subjects with moderate hepatic impairment and healthy subjects were observed. No dosage adjustment is necessary for patients with mild to moderate hepatic impairment. The effect of severe hepatic impairment on the pharmacokinetics of raltegravir has not been studied (see Clinical Pharmacology (12.3)).

8.7 Use in Patients with Renal Impairment

No clinically important pharmacokinetic differences between subjects with severe renal impairment and healthy subjects were observed. No dosage adjustment is necessary (see Clinical Pharmacology (12.3)).

10 OVERDOSAGE

No specific information is available on the treatment of overdosage with ISENTRESS. Doses as high as 1600-mg single dose and 800-mg twice-daily multiple doses were studied in healthy volunteers without evidence of toxicity. Occasional doses of up to 1800 mg per day were taken in the P005/P018 & P019 studies without evidence of toxicity.

In the event of an overdose, it is reasonable to employ the standard supportive measures, e.g., remove unabsorbed material from the gastrointestinal tract, employ clinical monitoring (including obtaining an electrocardiogram), and institute supportive therapy if required. The extent to which ISENTRESS may be dialyzable is unknown.

11 DESCRIPTION

ISENTRESS contains raltegravir potassium, a human immunodeficiency virus integrase strand transfer inhibitor. The chemical name for raltegravir potassium is N-((4-Fluorophenyl)methyl)-1,6-dihydro-5-hydroxy-1-methyl-2- (1-methyl-1-(((5-methyl-1,3,4-oxadiazol-2-yl)carbonyl)amino)ethyl)-6- oxo-4-pyrimidinecarboxamide monopotassium salt.

The empirical formula is C20H20FKN6O5 and the molecular weight is 482.51. The structural formula is:

(OBJECT OMITTED)

Raltegravir potassium is a white to off-white powder. It is soluble in water, slightly soluble in methanol, very slightly soluble in ethanol and acetonitrile and insoluble in isopropanol.

Each film-coated tablet of ISENTRESS for oral administration contains 434.4 mg of raltegravir potassium (as salt), equivalent to 400 mg of raltegravir (free phenol) and the following inactive ingredients: microcrystalline cellulose, lactose monohydrate, calcium phosphate dibasic anhydrous, hypromellose 2208, poloxamer 407 (contains 0.01% butylated hydroxytoluene as antioxidant), sodium stearyl fumarate, magnesium stearate. In addition, the film coating contains the following inactive ingredients: polyvinyl alcohol, titanium dioxide, polyethylene glycol 3350, talc, red iron oxide and black iron oxide.

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Raltegravir is an HIV-1 antiviral drug (see Clinical Pharmacology (12.4)).

12.2 Pharmacodynamics

In a monotherapy study raltegravir (400 mg twice daily) demonstrated rapid antiviral activity with mean viral load reduction of 1.66 log10 copies/mL by Day 10.

In Protocol 005 and Protocols 018 and 019, antiviral responses were similar among subjects regardless of dose.

Effects on Electrocardiogram

In a randomized, placebo-controlled, crossover study, 31 healthy subjects were administered a single oral supratherapeutic dose of raltegravir 1600 mg and placebo. Peak raltegravir plasma concentrations were approximately 4-fold higher than the peak concentrations following a 400 mg dose. ISENTRESS did not appear to prolong the QTc interval for 12 hours postdose. After baseline and placebo adjustment, the maximum mean QTc change was -0.4 msec (1-sided 95% upper Cl: 3.1 msec).

12.3 Pharmacokinetics

Absorption

Raltegravir is absorbed with a Tmax of approximately 3 hours postdose in the fasted state. Raltegravir AUC and Cmax increase dose proportionally over the dose range 100 mg to 1600 mg. Raltegravir C12hr increases dose proportionally over the dose range of 100 to 800 mg and increases slightly less than dose proportionally over the dose range 100 mg to 1600 mg. With twice-daily dosing, pharmacokinetic steady state is achieved within approximately the first 2 days of dosing. There is little to no accumulation in AUC and Cmax. The average accumulation ratio for C12hr ranged from approximately 1.2 to 1.6.

The absolute bioavailability of raltegravir has not been established.

In subjects who received 400 mg twice daily alone, raltegravir drug exposures were characterized by a geometric mean AUC0-12hr of 14.3 (mu)M-hr and C12hr of 142 nM.

Considerable variability was observed in the pharmacokinetics of raltegravir. For observed C12hr in Protocols 018 and 019, the coefficient of variation (CV) for inter-subject variability = 212% and the CV for intra-subject variability = 122%.

Effect of Food on Oral Absorption

ISENTRESS may be administered without regard to food. Administration of raltegravir following a high-fat meal increased raltegravir AUC by approximately 19%. A high-fat meal slowed the rate of absorption resulting in an approximately 34% decrease in Cmax, an 8.5-fold increase in C12hr, and a delay in Tmax following a single 400 mg dose. The effect of consumption of a range of food types on steady-state pharmacokinetics is not known. Raltegravir was administered without regard to food in the pivotal safety and efficacy studies in HIV-1 positive subjects.

Distribution

Raltegravir is approximately 83% bound to human plasma protein over the concentration range of 2 to 10 uM.

Metabolism and Excretion

The apparent terminal half-life of raltegravir is approximately 9 hours, with a shorter (alpha)-phase half-life (approximately 1 hour) accounting for much of the AUC. Following administration of an oral dose of radiolabeled raltegravir, approximately 51 and 32% of the dose was excreted in feces and urine, respectively. In feces, only raltegravir was present, most of which is likely derived from hydrolysis of raltegravir-glucuronide secreted in bile as observed in preclinical species. Two components, namely raltegravir and raltegravir-glucuronide, were detected in urine and accounted for approximately 9 and 23% of the dose, respectively. The major circulating entity was raltegravir and represented approximately 70% of the total radioactivity; the remaining radioactivity in plasma was accounted for by raltegravir-glucuronide. Studies using isoform-selective chemical inhibitors and cDNA-expressed UDP-glucuronosyltransferases (UGT) show that UGT1A1 is the main enzyme responsible for the formation of raltegravir-glucuronide. Thus, the data indicate that the major mechanism of clearance of raltegravir in humans is UGT1A1-mediated glucuronidation.

Special Populations

Pediatric

The pharmacokinetics of raltegravir in pediatric patients has not been established.

Age

The effect of age on the pharmacokinetics of raltegravir was evaluated in the composite analysis. No dosage adjustment is necessary.

Race

The effect of race on the pharmacokinetics of raltegravir was evaluated in the composite analysis. No dosage adjustment is necessary.

Gender

A study of the pharmacokinetics of raltegravir was performed in young healthy males and females. Additionally, the effect of gender was evaluated in a composite analysis of pharmacokinetic data from 103 healthy subjects and 28 HIV-1 infected subjects receiving raltegravir monotherapy with fasted administration. No dosage adjustment is necessary.

Hepatic Impairment

Raltegravir is eliminated primarily by glucuronidation in the liver. A study of the pharmacokinetics of raltegravir was performed in subjects with moderate hepatic impairment. Additionally, hepatic impairment was evaluated in the composite pharmacokinetic analysis. There were no clinically important pharmacokinetic differences between subjects with moderate hepatic impairment and healthy subjects. No dosage adjustment is necessary for patients with mild to moderate hepatic impairment. The effect of severe hepatic impairment on the pharmacokinetics of raltegravir has not been studied.

Renal Impairment

Renal clearance of unchanged drug is a minor pathway of elimination. A study of the pharmacokinetics of raltegravir was performed in subjects with severe renal impairment. Additionally, renal impairment was evaluated in the composite pharmacokinetic analysis. There were no clinically important pharmacokinetic differences between subjects with severe renal impairment and healthy subjects. No dosage adjustment is necessary. Because the extent to which ISENTRESS may be dialyzable is unknown, dosing before a dialysis session should be avoided.

UGT1A1 Polymorphism

Data currently available are not sufficient to determine the impact of UGT1A1 polymorphism on raltegravir pharmacokinetics.

Drug Interactions (see Drug Interactions (7)). -0-

      Table 4: Effect of Other Agents on the Pharmacokinetics of

                             Raltegravir


                                               Ratio (90% Confidence

                                              Interval) of Raltegravir

                                                  Pharmacokinetic

                                              Parameters with/without

                                                Coadministered Drug;

                                                  No Effect = 1.00

                                              ------------------------

               Coadministered

Coadministered      Drug         Raltegravir

      Drug       Dose/Schedule  Dose/Schedule   n           Cmax

-------------- --------------- -------------- ------ -----------------

atazanavir       400 mg daily   100 mg single

                                     dose         10 1.53 (1.11, 2.12)

-------------- --------------- -------------- ------ -----------------

atazanavir/     300 mg/100 mg   400 mg twice

 ritonavir           daily          daily         10 1.24 (0.87, 1.77)

-------------- --------------- -------------- ------ -----------------

efavirenz        600 mg daily   400 mg single

                                     dose          9 0.64 (0.41, 0.98)

-------------- --------------- -------------- ------ -----------------

rifampin         600 mg daily   400 mg single

                                     dose          9 0.62 (0.37, 1.04)

-------------- --------------- -------------- ------ -----------------

ritonavir       100 mg twice    400 mg single

                     daily           dose         10 0.76 (0.55, 1.04)

-------------- --------------- -------------- ------ -----------------

tenofovir        300 mg daily   400 mg twice

                                    daily          9 1.64 (1.16, 2.32)

-------------- --------------- -------------- ------ -----------------

tipranavir/     500 mg/200 mg   400 mg twice    15

 ritonavir        twice daily       daily      (14

                                               for

                                              Cmin)  0.82 (0.46, 1.46)

-------------- --------------- -------------- ------ -----------------

-0-
                                   Ratio (90% Confidence Interval) of

                                       Raltegravir Pharmacokinetic

                                         Parameters with/without

                                          Coadministered Drug;

                                            No Effect = 1.00

                                   -----------------------------------

       Coadministered Drug                   AUC            Cmin

---------------------------------- ----------------- -----------------


atazanavir                         1.72 (1.47, 2.02) 1.95 (1.30, 2.92)

---------------------------------- ----------------- -----------------

atazanavir/ ritonavir              1.41 (1.12, 1.78) 1.77 (1.39, 2.25)

---------------------------------- ----------------- -----------------

efavirenz                          0.64 (0.52, 0.80) 0.79 (0.49, 1.28)

---------------------------------- ----------------- -----------------

rifampin                           0.60 (0.39, 0.91) 0.39 (0.30, 0.51)

---------------------------------- ----------------- -----------------

ritonavir                          0.84 (0.70, 1.01) 0.99 (0.70, 1.40)

---------------------------------- ----------------- -----------------

tenofovir                          1.49 (1.15, 1.94) 1.03 (0.73, 1.45)

---------------------------------- ----------------- -----------------

tipranavir/ ritonavir              0.76 (0.49, 1.19) 0.45 (0.31, 0.66)

---------------------------------- ----------------- -----------------

12.4 Microbiology

Mechanism of Action

Raltegravir inhibits the catalytic activity of HIV-1 integrase, an HIV-1 encoded enzyme that is required for viral replication. Inhibition of integrase prevents the covalent insertion, or integration, of unintegrated linear HIV-1 DNA into the host cell genome preventing the formation of the HIV-1 provirus. The provirus is required to direct the production of progeny virus, so inhibiting integration prevents propagation of the viral infection. Raltegravir did not significantly inhibit human phosphoryltransferases including DNA polymerases (alpha), B, and (gamma).

Antiviral Activity in Cell Culture

Raltegravir at concentrations of 31 +/- 20 nM resulted in 95% inhibition (EC95) of viral spread (relative to an untreated virus-infected culture) in human T-lymphoid cell cultures infected with the cell-line adapted HIV-1 variant H9IIIB. In addition, raltegravir at concentrations of 6 to 50 nM resulted in 95% inhibition of viral spread in cultures of mitogen-activated human peripheral blood mononuclear cells infected with diverse, primary clinical isolates of HIV-1, including isolates resistant to reverse transcriptase inhibitors and protease inhibitors. Raltegravir also inhibited replication of an HIV-2 isolate when tested in CEMx174 cells (EC95 value = 6 nM). Additive to synergistic antiretroviral activity was observed when human T-lymphoid cells infected with the H9IIIB variant of HIV-1 were incubated with raltegravir in combination with non-nucleoside reverse transcriptase inhibitors (delavirdine, efavirenz, or nevirapine); nucleoside analog reverse transcriptase inhibitors (abacavir, didanosine, lamivudine, stavudine, tenofovir, zalcitabine, or zidovudine); protease inhibitors (amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, or saquinavir); or the entry inhibitor enfuvirtide.

Resistance

The mutations observed in the HIV-1 integrase coding sequence that contributed to raltegravir resistance (evolved either in cell culture or in subjects treated with raltegravir) generally included an amino acid substitution at either Q148 (changed to H, K, or R) or N155 (changed to H) plus one or more additional substitutions (i.e., L74M/R, E92Q, T97A, E138A/K, G140A/S, V151I, G163R, H183P, Y226D/F/H, S230R and D232N). Amino acid substitution at Y143C/H/R is another pathway to raltegravir resistance.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term (2-year) carcinogenicity studies of raltegravir in rodents are ongoing.

No evidence of mutagenicity or genotoxicity was observed in in vitro microbial mutagenesis (Ames) tests, in vitro alkaline elution assays for DNA breakage and in vitro and in vivo chromosomal aberration studies.

No effect on fertility was seen in male and female rats at doses up to 600 mg/kg/day which resulted in a 3-fold exposure above the exposure at the recommended human dose.

14 CLINICAL STUDIES

Description of Clinical Studies

The evidence of efficacy of ISENTRESS is based on the analyses of 24-week data from 2 ongoing, randomized, double-blind, placebo-controlled trials, BENCHMRK 1 and BENCHMRK 2 (Protocols 018 and 019), in antiretroviral treatment-experienced HIV-1 infected adult subjects. These efficacy results were supported by the 48-week analysis of a randomized, double-blind, controlled, dose-ranging trial, Protocol 005, in antiretroviral treatment-experienced HIV-1 infected adult subjects.

Treatment-Experienced Subjects

BENCHMRK 1 and BENCHMRK 2 are Phase III studies to evaluate the safety and antiretroviral activity of ISENTRESS 400 mg twice daily in combination with an optimized background therapy (OBT), versus OBT alone, in HIV-infected subjects, 16 years or older, with documented resistance to at least 1 drug in each of 3 Classes (NNRTIs, NRTIs, PIs) of antiretroviral therapies. Randomization was stratified by degree of resistance to PI (1PI vs. >1PI) and the use of enfuvirtide in the OBT. Prior to randomization, OBT was selected by the investigator based on genotypic/phenotypic resistance testing and prior ART history.

Table 5 shows the demographic characteristics of subjects in the ISENTRESS 400 mg twice daily arm and subjects in the placebo arm. -0-

                  Table 5: Baseline Characteristics


                                                ISENTRESS

                                                  400 mg

                                                Twice Daily  Placebo

BENCHMRK 1 and 2 Pooled                           + OBT        + OBT

                                                (N = 462)   (N = 237)

--------------------------------------------- ------------- ----------

Gender n (%)

--------------------------------------------- ------------- ----------

Male                                           405 (87.7)   210 (88.6)

Female                                          57 (12.3)   27 (11.4)

--------------------------------------------- ------------- ----------

Race n (%)

--------------------------------------------- ------------- ----------

White                                          301 (65.2)   173 (73.0)

Black                                           66 (14.3)   26 (11.0)

Asian                                           16 (3.5)     6 (2.5)

Hispanic                                        53 (11.5)    19 (8.0)

Others                                          26 (5.6)     13 (5.5)

--------------------------------------------- ------------- ----------

Age (years)

--------------------------------------------- ------------- ----------

Median (min, max)                              45.0 (16 to   45.0 (17

                                                   74)        to 70)

--------------------------------------------- ------------- ----------

CD4+ Cell Count

--------------------------------------------- ------------- ----------

Median (min, max), cells/mm3                    119 (1 to   123 (0 to

                                                  792)         759)

=50 cells/mm3, n (%)                           146 (31.6)   78 (32.9)

>50 and =200 cells/mm3, n (%)                  173 (37.4)   85 (35.9)

--------------------------------------------- ------------- ----------

Plasma HIV-1 RNA

--------------------------------------------- ------------- ----------

Median (min, max), log10 copies/mL            4.8 (2 to 6)  4.7 (2 to

                                                                6)

>100,000 copies/mL, n (%)                      164 (35.5)   78 (32.9)

--------------------------------------------- ------------- ----------

History of AIDS n (%)

--------------------------------------------- ------------- ----------

Yes                                            426 (92.2)   216 (91.1)

--------------------------------------------- ------------- ----------

Prior Use of ART, Median (1st Quartile, 3rd Quartile)

----------------------------------------------------------- ----------

Years of ART Use                              10.1 (7.4 to  10.2 (7.9

                                                  12.1)      to 12.4)

Number of ART                                  12.0 (9 to   12.0 (9 to

                                                   15)         14)

--------------------------------------------- ------------- ----------

Hepatitis Co-infection* n (%)

--------------------------------------------- ------------- ----------

No Hepatitis B or C virus                      385 (83.3)   201 (84.8)

Hepatitis B virus only                          36 (7.8)     7 (3.0)

Hepatitis C virus only                          37 (8.0)    27 (11.4)

Co-infection of Hepatitis B and C virus          4 (0.9)     2 (0.8)

--------------------------------------------- ------------- ----------

Stratum n (%)

--------------------------------------------- ------------- ----------

Enfuvirtide in OBT                             175 (37.9)   89 (37.6)

Resistant to =>2 PI                            447 (96.8)   226 (95.4)

--------------------------------------------- ------------- ----------

*Hepatitis B virus surface antigen positive or hepatitis C virus antibody positive.

Table 6 compares the characteristics of optimized background therapy at baseline in the ISENTRESS 400 mg twice daily arm and subjects in the control arm. -0-

     Table 6: Characteristics of Optimized Background Therapy at

                               Baseline


                                                 ISENTRESS

                                                   400 mg

                                                   Twice

                                                   Daily     Placebo

            BENCHMRK 1 and 2 Pooled                + OBT      + OBT

                                                 (N = 462)  (N = 237)

------------------------------------------------ ---------- ----------

             Number of ARTs in OBT

------------------------------------------------ ---------- ----------

               Median (min, max)                 4.0 (1 to  4.0 (2 to

                                                     7)         7)

------------------------------------------------ ---------- ----------

    Number of Active PI in OBT by Phenotypic

                Resistance Test*

------------------------------------------------ ---------- ----------

                       0                         166 (35.9)  97 (40.9)

                   1 or more                     278 (60.2) 137 (57.8)

------------------------------------------------ ---------- ----------

      Phenotypic Sensitivity Score (PSS)+

------------------------------------------------ ---------- ----------

                       0                          67 (14.5)  44 (18.6)

                       1                         145 (31.4)  71 (30.0)

                       2                         142 (30.7)  66 (27.8)

                   3 or more                      85 (18.4)  48 (20.3)

------------------------------------------------ ---------- ----------

       Genotypic Sensitivity Score (GSS)+

------------------------------------------------ ---------- ----------

                       0                         115 (24.9)  65 (27.4)

                       1                         178 (38.5)  96 (40.5)

                       2                         111 (24.0)  49 (20.7)

                   3 or more                      51 (11.0)   23 (9.7)

------------------------------------------------ ---------- ----------

* Darunavir use in OBT in darunavir naive subjects was counted as one active PI. + The Phenotypic Sensitivity Score (PSS) and the Genotypic Sensitivity Score (GSS) were defined as the total oral ARTs in OBT to which a subject's viral isolate showed phenotypic sensitivity and genotypic sensitivity, respectively, based upon phenotypic and genotypic resistance tests. Enfuvirtide use in OBT in enfuvirtide-naive subjects was counted as one active drug in OBT in the GSS and PSS. Similarly, darunavir use in OBT in darunavir-naive subjects was counted as one active drug in OBT.

Week 24 outcomes for

Posted: February 2008

View comments

Hide
(web5)