A Pilot Study Assessing the Integrase Inhibitor GSK1349572 in HIV-infected Persons With Virus Resistant to Raltegravir

Mean change from Baseline in Plasma HIV-1 RNA was assessed on Day 6 to 8, Day 11, and Weeks 4, 12, 24, 48, 72, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, and 264 using data of the observed cases. Study Day 1 was considered as Baseline. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

The number of participants with plasma HIV-1 RNA <400 c/mL or <50 c/mL was assessed at Weeks 4, 12, 24, 48, 72, and 96 per the Food and Drug Administration's Time to Loss of Virological Response (TLOVR) algorithm. Using the TLOVR algorithm, participants are considered to have failed on therapy if they never achieved confirmed RNA levels below the threshold, if they had confirmed rebound of RNA above the threshold, if they made a non-permitted change in background regimen, or if they permanently discontinued investigational product for any reason.

The number of participants with plasma HIV-1 RNA <400 c/mL or <50 c/mL was assessed at Weeks 48, 72, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, and 264 using data of observed cases. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

Change from Baseline in CD4+ cell count was assessed at Day 11 and at Weeks 4, 12, 24, 48, 72, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, and 264 . Study Day 1 was considered as Baseline. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

The maximum plasma concentration (Cmax), minimum plasma concentration (Cmin), and concentration at the end of a dosing interval (Ctau) of DTG were assessed at Day 10. Blood samples for pharmacokinetic (PK) assessments were collected at pre-dose (within 15 minutes prior to dose) and 2, 3, 4, 8, and 24 hours post-dose on Day 10 for DTG 50 mg OD and pre-dose (within 15 minutes prior to dose) and 2, 3, 4 and 8 hours post morning dose and 12 hours post evening dose for DTG 50 mg BID.

The plasma DTG concentration immediately prior to dosing at steady state (C0) was assessed at Day 10, and Weeks 4 and 24. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose).

The tmax is defined as the time of occurrence of the maximum plasma concentration (Cmax). The tmax was assessed at Day 10. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose) and 2, 3, 4, 8, and 24 hours post-dose on Day 10 for DTG 50 mg OD and pre-dose (within 15 minutes prior to dose) and 2, 3, 4 and 8 hours post morning dose and 12 hours post evening dose for DTG 50 mg BID.

AUC is defined as the area under the DTG concentration-time curve as a measure of drug exposure. AUC(0-24) is defined as the area under the concentration-time curve from time zero (pre-dose) to 24 hours. AUC0-24 of DTG was assessed at Day 10. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose) and 2, 3, 4, 8, and 24 hours post-dose on Day 10 for DTG 50 mg OD and pre-dose (within 15 minutes prior to dose) and 2, 3, 4 and 8 hours post morning dose and 12 hours post evening dose for DTG 50 mg BID.

The number of participants with post-Baseline emergent HIV-1 disease progression (Acquired immunodeficiency syndrome (AIDS) or death) was assessed per the Centers for Disease Control and Prevention (CDC) 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. The CDC classifies HIV infection as Category A (participants with asymptomatic HIV infection, acute HIV infection with accompanying illness, or persistent generalized lymphadenopathy), Category B (participants with symptomatic non-AIDS condition, i.e., conditions that are attributed to HIV infection or are indicative of a defect in cell-mediated immunity; or conditions are considered by physicians to have a clinical course or to require management that is complicated by HIV infection), and Category C (includes AIDS indicator conditions as defined by diagnostic or presumptive measures).

The number of participants with HIV-1 disease progression (AIDS or death) was assessed per the CDC 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. The CDC classifies HIV infection as Category A (participants with asymptomatic HIV infection, acute HIV infection with accompanying illness, or persistent generalized lymphadenopathy), Category B (participants with symptomatic non-AIDS condition, i.e., conditions that are attributed to HIV infection or are indicative of a defect in cell-mediated immunity; or conditions are considered by physicians to have a clinical course or to require management that is complicated by HIV infection), and Category C (includes AIDS indicator conditions as defined by diagnostic or presumptive measures).

PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log10 c/mL unless <400 c/mL or an increase of >= 1.0 log10 c/mL from nadir; and at or after Week 16, ≥400 c/mL. PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of the original sample.

At Baseline, the integrase genotypic results were used to document resistance to raltegravir (RAL) and for the allocation of participants to one of two genotypic groups according to their RAL signature mutations to ensure a broad range of sensitivity to DTG. These results were not used to pre-define subgroup for analysis.

Summary of median fold change in sensitivity to DTG by Integrase (IN) mutational group was assessed. The IN mutational group comprises of the following mutations: Q148 +2, Q148 +1, mixture (participants with virus containing more than one Y143, Q148 or N155 mutation at Day 1), Y143, N155, other (participants with virus having no mutations at codons 143, 148, or 155 at Day 1). Fold change (FC) is the fold change in 50% Inhibitory Concentration (IC50) relative to the wild-type control virus.

An analysis of changes at specific amino acids in the IN coding region associated with resistance to raltegravir, elvitegravir, or DTG was performed at Day 1 and at the time of PDVF. PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log10 c/mL unless <400 c/mL or an increase of >= 1.0 log10 c/mL from nadir; and at or after Week 16, ≥400 c/mL. PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of the original sample.

The FC in IC50 (50% inhibitory concentration) for DTG relative to wild-type virus was determined for virus isolated at Baseline and at the time of PDVF.The number of participants with the indicated change (ratio) in the two values at the time of PDVF is presented. PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log 10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log 10 c/mL unless <400 c/mL or an increase of >=1.0 log 10 c/mL from nadir; and at or after Week 16, ≥400 c/mL . PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of original sample.

Hematology and clinical chemistry data were summarized according to Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, dated December 2004. Grade 1, Mild; Grade 2, Moderate; Grade 3, Severe; Grade 4, Potentially life-threatening. Data are presented for only those parameters for which an increase to Grade 3 or Grade 4 occurred. The Grade 3 and Grade 4 clinical chemistry toxicities included: Albumin, Alkaline Phosphatase, Amylase, Aspartate Amino Transferase, Carbon dioxide content/Bicarbonate, Creatinine, Creatinine Clearance, Hypercalcemia, Hyperglycaemia, Hyperkalemia, Hypernatremia, Hypocalcemia, Hypoglycaemia, Hypokalemia, Hyponatremia, LDL Cholesterol, Magnesium, Phosphorus inorganic, and Total Bilirubin, Alanine Amino Transferase, Calcium, Chloride, Cholesterol, Creatine Kinase, Direct Bilirubin, Glucose, High Density Lipid (HDL), Cholesterol direct, Lipase, Potassium, Sodium, Total Cholesterol, Triglycerides, Urea/Blood Urine Nitrogen.

Hematology and clinical chemistry data were summarized according to Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, dated December 2004. Grade 1, Mild; Grade 2, Moderate; Grade 3, Severe; Grade 4, Potentially life-threatening. Data are presented for only those parameters for which an increase to Grade 3 or Grade 4 occurred. The Grade 3 and Grade 4 hematological toxicities included: Hemoglobin, Platelet Count, Total Neutrophils, and White Blood Cell count.