Safety, Tolerability and Pharmacokinetics of Efavirenz in HIV-Infected Children

Cmax and Cmin were derived from plasma concentrations versus time using a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). The lower limit of quantification (LLOQ) for EFV was 10.0 nanograms per milliliter (ng/mL) and the upper limit of quantification (ULOQ) was 8,000 ng/mL. Cmax and Cmin were recorded directly from experimental observations. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. Cmax and Cmin were measured in ng/mL.

Plasma concentrations were obtained using a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). The lower limit of quantification (LLOQ) for EFV was 10.0 nanograms per milliliter (ng/mL) and the upper limit of quantification (ULOQ) was 8,000 ng/mL. AUC(TAU) was calculated by log- and linear trapezoidal summations. If a concentration was < LLOQ at time TAU, the value of the concentration at time TAU was estimated using the quotient of the last quantifiable concentration and λ. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters summarized using geometric means. AUC(TAU) was measured in micromolars*time (µM•h).

Plasma concentrations of EFV were obtained using a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). The lower limit of quantification (LLOQ) for EFV was 10.0 nanograms per milliliter (ng/mL) and the upper limit of quantification (ULOQ) was 8,000 ng/mL. CLT/F was calculated by dividing the dose of EFV by AUC(TAU) of EFV. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. CLT/F was measured in liters per hour (L/h).

Plasma concentrations of EFV were determined using a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). The lower limit of quantification (LLOQ) for EFV was 10.0 nanograms per milliliter (ng/mL) and the upper limit of quantification (ULOQ) was 8,000 ng/mL. CLT/F/kg was calculated by dividing CLT/F by body weight in kilograms (kg). Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. CLT/F/kg was measured in liters per hour per kilogram (L/h/kg).

Algorithms: Confirmed Virologic Response (CVR) non-completer = failure (NC = F): participants were responders if they achieved confirmed HIV RNA < 400 c/mL at Week 48; participants were failures if virologic rebound occurred at or before Week 48; therapy discontinued before Week 48; no response by Week 48, or missing HIV RNA at Week 48 and beyond. Virologic Response - Observed Cases (VR-OC): participants were responders according to a single on-treatment HIV RNA < 400 c/mL closest to the planned Week 48 visit and within the predefined Week 48 visit window; those on treatment and missing their Week 48 measurement were responders only if previous and subsequent measurements to the Week 48 visit window were < 400 c/mL; denominator was all who remained on treatment through Week 48. Snapshot: participants were responders according to the last on-treatment HIV RNA < 400 c/mL in the predefined Week 48 visit window; denominator was all treated participants.

Algorithms: Confirmed Virologic Response (CVR) non-completer = failure (NC = F): participants were responders if they achieved confirmed HIV RNA < 50 c/mL at Week 48; participants were failures if virologic rebound occurred at or before Week 48; therapy discontinued before Week 48; no response by Week 48, or missing HIV RNA at Week 48 and beyond. Virologic Response - Observed Cases (VR-OC): participants were responders according to a single on-treatment HIV RNA < 50 c/mL closest to the planned Week 48 visit and within the predefined Week 48 visit window; those on treatment and missing their Week 48 measurement were responders only if previous and subsequent measurements to the Week 48 visit window were < 50 c/mL; denominator was all who remained on treatment through Week 48. Snapshot: participants were responders according to the last on-treatment HIV RNA < 50 c/mL in the predefined Week 48 visit window; denominator was all treated participants.

Algorithms: Confirmed Virologic Response (CVR) non-completer = failure (NC = F): participants were responders if they achieved confirmed HIV RNA < 400 c/mL at Week 24; participants were failures if virologic rebound occurred at or before Week 24; therapy discontinued before Week 24; no response by Week 24, or missing HIV RNA at Week 24 and beyond. Virologic Response - Observed Cases (VR-OC): participants were responders according to a single on-treatment HIV RNA < 400 c/mL closest to the planned Week 24 visit and within the predefined Week 24 visit window; those on treatment and missing their Week 24 measurement were responders only if previous and subsequent measurements to the Week 24 visit window were < 400 c/mL; denominator was all who remained on treatment through Week 24.

Algorithms: Confirmed Virologic Response (CVR) non-completer = failure (NC = F): participants were responders if they achieved confirmed HIV RNA < 50 c/mL at Week 24; participants were failures if virologic rebound occurred at or before Week 24; therapy discontinued before Week 24; no response by Week 24, or missing HIV RNA at Week 24 and beyond. Virologic Response - Observed Cases (VR-OC): participants were responders according to a single on-treatment HIV RNA < 50 c/mL closest to the planned Week 24 visit and within the predefined Week 24 visit window; those on treatment and missing their Week 24 measurement were responders only if previous and subsequent measurements to the Week 24 visit window were < 50 c/mL; denominator was all who remained on treatment through Week 24.

HIV RNA measured as log10 copies per milliliter (c/mL) plasma. HIV RNA values ≥ 1,000 c/mL were considered evidence of infection. A decrease in number of c/mL is an improvement for the participant. HIV RNA was first measured using the ultrasensitive and standard Roche Amplicor PCR, version 1.5, and then the method of measurement was switched to the COBAS AmpliPrep/COBAS TaqMan HIV IVD method. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

A CD4 cell is an antigenic marker of helper/inducer T cells. These cells were counted during the hematology cell counts performed during a Complete Blood Cell count (CBC) performed by the Central Laboratory. CD4 are measured as number of cells per millimeters to the third power (cells/mm^3). An increase from baseline in the number of CD4 cells is an improvement. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

A CD4 cell is an antigenic marker of helper/inducer T cells. These cells were counted during the hematology cell counts performed during a Complete Blood Cell count (CBC) performed by the Central Laboratory. CD4 are measured as number of cells per millimeter to the third power (cells/mm^3). Percent of CD4 cells is the number of CD4 cells per total number of cells measured*100. An increase in the percent of CD4 cells is an improvement. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

Center for Disease Control and Prevention (CDC) classification of Class C events used to define acquired immunodeficiency syndrome (AIDS): include pneumocystis pneumonia, pneumonia, pulmonary tuberculosis. AE=new unfavorable symptom, sign, or disease or worsening of a preexisting condition that may not have a causal relationship with treatment. SAE=medical event that at any dose results in death, persistent or significant disability/incapacity, or drug dependency/abuse; is life-threatening, an important medical event, or a congenital anomaly/birth defect; or requires or prolongs hospitalization. Treatment-related=having certain, probable, possible, or missing relationship to study drug. AE Severity: Grade (Gr) 1=Mild, Gr 2=Moderate, Gr 3=Severe, Gr 4= Potentially Life-threatening or disabling (Division of AIDs Table, published December 2004). Baseline=within 50 days post screening, prior to start of study drug. 2 categories for death presented (on-treatment and enrolled/not treated).

Abnormalities were determined from laboratory measurements analyzed at the central or local laboratory. Division of AIDS Table (DAIDS) for Grading Severity of Adult and Pediatric AEs version (v) Dec 2004. Upper limit of normal (ULN): lower limit of normal (LLN), alanine transaminase (ALT); aspartate aminotransferase (AST); alkaline phosphatase (ALP). ALT Grade (Gr) 1: 1.25 to 2.5*ULN; Gr 2: 2.6 to 5.0*ULN; Gr 3: 5.1 to 10.0*ULN; Gr 4: >10.0*ULN. AST Gr 1: 1.25 to 2.5*ULN; Gr 2: 2.6 to 5.0*ULN; Gr 3: 5.1 to 10.0*ULN; Gr 4: >10.0*ULN. Total bilirubin Gr 1: 1.25 to 1.5*ULN; Gr 2: 1.6 to 2.5*ULN; Gr 3: 2.6 to 5.0*ULN; Gr 4: >5.0*ULN. ALP (U/L) Gr 1: 1.25 to 2.5*ULN, Gr 2: 2.6 to 5.0*ULN, Gr 3: 5.1 to 10.0*ULN, Gr 4: >10.0*ULN. Albumin (low) Gr 1: 3 grams per deciliter (g/dL) to <LLN ; Gr 2: 2.0-2.9 g/dL; Gr 3: < 2 g/dL. Gr 4: Not applicable. Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

Abnormalities were determined from measurements analyzed at central or local laboratory. DAIDS Grading Severity of Adult and Pediatric AEs v Dec 2004. Total Cholesterol (fasting) Gr 1: 170 - 199 mg/dL; Gr 2: 200 - 300 mg/dL; Gr 3 >300 mg/dL; Gr 4 Not Applicable(NA). LDL cholesterol, fasting: Gr 1: 110-129 mg/dL; Gr 2: 130-189 mg/dL; Gr 3 >=190 mg/dL; Gr 4 NA. Triglycerides, fasting: Gr 1: NA; Gr 2 500-750 mg/dL; Gr 3: 751-1,200 mg/dL; Gr 4: >1,200 mg/dL. Glucose, serum, high, fasting and (non-fasting): Gr 1: 110 - 125 (116-160) mg/dL; Gr 2: 126-250 (161- 250) mg/dL; Gr 3: 251-500 (251-500) mg/dL; Gr 4: >500 (> 500) mg/dL. Glucose, serum, low, >=1 month of age (<1 month): Gr 1: 55-64 (50-54) mg/dL; Gr 2: 40-54 (40-49) mg/dL; Gr 3: 30-39 (30-39) mg/dL; Gr 4: <30 (<30) mg/dL. Baseline: within 50 days after the screening visit and was prior to start of study medication (Week 1). Only those in 4th arm were old enough to fast prior to testing; other arms did not have fasting samples taken.

Central/local laboratory. DAIDS v 2004. Bicarbonate, low: Gr 1: 16 milliequivalents per liter (mEq/L) - < LLN; Gr 2: 11.0-15.9 mEq/L; Gr 3: 8.0-10.9 mEq/L; Gr 4: <8.0 mEq/L; calcium, high Gr 1: 10.6-11.5 mg/dL; Gr 2: 11.6-12.5 mg/dL; Gr 3 12.6-13.5 mg/dL; Gr 4: >13.5 mg/dL; calcium, low Gr1: 7.8-8.4 mg/dL; Gr2: 7.0-7.7 mg/dL; Gr3: 6.1-6.9 mg/dL; Gr 4: <6.1 mg/dL; creatinine Gr1: 1.1-1.3*ULN; Gr 2: 1.4-1.8*ULN; Gr 3: 1.9-3.4*ULN; Gr 4: >=3.5*ULN; lipase Gr 1: 1.1-1.5*ULN; Gr 2: 1.6-3.0*ULN; Gr 3: 3.1-5.0*ULN; Gr 4: >5.0*ULN; potassium high (low) Gr 1: 5.6-6.0 (3.0-3.4) mEq/L; Gr 2: 6.1-6.5 (2.5-2.9) mEq/L; Gr 3: 6.6-7.0 (2.0-2.4) mEq/L; Gr 4: >7.0 (<2.0) mEq/L; sodium, high (low) Gr 1: 146-150 (130-135) mEq/L; Gr 2: 151-154 (125-129) mEq/L; Gr 3: 155-159 (121-124) mEq/L; Gr 4: >=160 (<=120) mEq/L; uric acid Gr 1: 7.5-10.0 mg/dL; Gr 2: 10.1-12.0 mg/dL; Gr 3: 12.1-15.0 mg/dL; Gr 4: >15.0 mg/dL. Baseline within 50 days post screening, prior to start of study medication.

Abnormalities were determined from laboratory measurements analyzed at the central or local laboratory. DAIDS DAIDS Grading Severity of Adult and Pediatric AEs v Dec 2004. Hemoglobin Gr 1: 8.5-10.0 g/dL; Gr 2: 7.5-8.4 g/dL; Gr 3: 6.50-7.4 g/dL; Gr 4: <6.5 g/dL; Platelets, decreased: Gr 1: 100.000-124.999*10^9/L; Gr 2: 50.000-99.999*10^9/L; Gr 3: 25.000-49.999*10^9/L; Gr 4: <25.000*10^9/L; White blood cell count (WBC) decreased Gr 1: 2.000-2.500*10^9/L; Gr 2: 1.500-1.999*10^9/L; Gr 3: 1.000-1.499*10^9/L; Gr 4: <1.000*10^9/L. Baseline visit was within 50 days post screening and was prior to start of study drug (Week 1).

At baseline, treatment-naïve screened by genotype; treatment-experienced screened by genotype and phenotype. Genotypic resistance: presence of substitutions in reverse transcriptase (RT) gene and/or presence of mutations that confer resistance to nucleoside reverse transcriptase inhibitor class. Phenotype resistance: FTC: > 3.1* the 50% inhibitory concentration (IC50) of the control strain; EFV: > 3.3* IC50 ; ddI: > 2.6*IC50. Virologic failure: <1 log10 decrease in HIV RNA from Week 16 on; confirmatory HIV RNA within 14-35 days; HIV RNA > 10,000 c/mL with prior value < 400 c/mL; confirmatory HIV RNA 14-35 days. Monogram Biosciences Phenosense™ assay ( EFV and FTC: biologic cutoffs=3 and 3.5, respectively; ddI: clinical cutoff: lower limit=1.39; upper limit = 2.2.); VircoTYPE™ HIV-1 v 4.3.01( EFV, FTC: biologic cutoffs=3.3 and 3.1, respectively;ddI: clinical cutoff: lower limit = 0.9; upper limit = 2.6. No genotypic/phenotypic changes in presence of virologic failure=no resistance.

PK parameters were evaluated 2 weeks post start of dosing. Based on observed AUC, measured in micromoles (μM)*h, dosing was increased, remained the same, or decreased at next visit to achieve the desired AUC (110-380 μM*h). Number of participants who became resistant was categorized by those who required additional dosing after Week 2 (AUC<110 μM*h) and those who did not. AUC: derived from plasma concentration of EFV versus time. Plasma concentrations for determination of AUC were obtained using a validated LC-MS/MS method. LLOQ for EFV = 10.0 ng/mL and ULOQ = 8,000 ng/mL. AUC calculated by log- and linear trapezoidal summations. Genotypic resistance=presence of substitutions in the RT gene and/or presence of mutations that confer resistance to entire nucleoside reverse transcriptase inhibitor class. Phenotypic resistance=EFV: > 3.3* IC50 of control strain. Assays: Monogram Biosciences Phenosense™ GT (EFV biologic cutoff=3) and VircoTYPE™ HIV-1 v 4.3.01( EFV biologic cutoff=3.3).

Cmax and Cmin were derived from plasma concentration versus time. Plasma concentrations for ddI were determined using a validated LC/MS/MS assay. All reportable Cmin values were <LLOQ in all age groups except >=6 months to < 2 years (Group 2); LLOQ/2 was imputed for those summary statistics;in Group 2, 9 of 10 Cmin values were <LLOQ; LLOQ/2 was imputed for those samples for summary statistics. The lower limit of quantification (LLOQ) for ddI was 2.50 nanograms per milliliter (ng/mL). Cmax and Cmin were recorded directly from experimental observations. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. Cmax and Cmin were measured in ng/mL.

Plasma concentrations were obtained using a validated LC-MS/MS at Week 2. The lower limit of quantification (LLOQ) for ddI was 2.50 nanograms per milliliter (ng/mL). AUC(TAU) was calculated by log- and linear trapezoidal summations. If a concentration was < LLOQ at time TAU, the value of the concentration at time TAU was estimated using the quotient of the last quantifiable concentration and λ. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters summarized using geometric means. AUC(TAU) was measured in nanograms*time per milliliter (ng•h/mL).

Plasma concentrations for ddI were determined using a validated LC/MS/MS assay. The LLOQ for ddI was 2.50 nanograms per milliliter (ng/mL). CLT/F was calculated by dividing the dose of ddI by AUC(TAU) of ddI. Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. CLT/F was measured in liters per hour (L/h).

Plasma concentrations for ddI were determined using a validated LC/MS/MS assay. The LLOQ for ddI was 2.50 nanograms per milliliter (ng/mL). CLT/F/kg was calculated by dividing CLT/F by body weight in kilograms (kg). Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the pharmacokinetic parameters were summarized using geometric means. CLT/F/kg was measured in liters per hour per kilogram (L/h/kg).

Plasma concentrations for ddI were determined using a validated LC/MS/MS assay. The LLOQ for ddI was 2.50 nanograms per milliliter (ng/mL). Blood samples were collected before study drug administration and at 0.5, 1, 3, 5, 8, and 24 hours after study drug administration from an indwelling catheter or by direct venipuncture and the T-HALF was summarized using a mean. Terminal elimination plasma half-life=ln2 divided by K where K is the absolute value of the slope of the terminal phase of the plasma profile as determined by log-linear regression of at least three data points. T-HALF was measured in hours (h).

Virologic Response - Observed Cases (VR-OC): participants were responders at a specific week according to a single on-treatment HIV RNA < 400 c/mL closest to the planned visit and within the predefined visit window; those on treatment and missing their specific week measurement were responders only if previous and subsequent measurements to that week visit window were < 400 c/mL; denominator was all who remained on treatment through the specific week.

Virologic Response - Observed Cases (VR-OC): participants were responders at a specific week according to a single on-treatment HIV RNA < 50 c/mL closest to the planned visit and within the predefined visit window; those on treatment and missing their specific week measurement were responders only if previous and subsequent measurements to that week visit window were < 50 c/mL; denominator was all who remained on treatment through the specific week.

HIV RNA measured as log10 copies per milliliter (c/mL) plasma. HIV RNA values ≥ 1,000 c/mL were considered evidence of infection. A decrease in number of c/mL is an improvement for the participant. HIV RNA was first measured using the ultrasensitive and standard Roche Amplicor PCR, version 1.5, and then the method of measurement was switched to the COBAS AmpliPrep/COBAS TaqMan HIV IVD method. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

A CD4 cell is an antigenic marker of helper/inducer T cells. These cells were counted during the hematology cell counts performed during a Complete Blood Cell count (CBC) performed by the Central Laboratory. CD4 are measured as number of cells per millimeters to the third power (cells/mm^3). An increase from baseline in the number of CD4 cells is an improvement. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).

A CD4 cell is an antigenic marker of helper/inducer T cells. These cells were counted during the hematology cell counts performed during a Complete Blood Cell count (CBC) performed by the Central Laboratory. CD4 are measured as number of cells per millimeter to the third power (cells/mm^3). Percent of CD4 cells is the number of CD4 cells per total number of cells measured*100. An increase in the percent of CD4 cells is an improvement. The Baseline visit was within 50 days after the screening visit and was prior to start of study medication (Week 1).