CLINICAL PHARMACOLOGY
Mechanism Of Action
Raltegravir is an HIV-1 antiviral drug [see Microbiology].
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.
Cardiac Electrophysiology
At a dose 1.33 times the maximum approved recommended dose (and peak concentrations 1.25-fold higher than the maximum approved dose), raltegravir does not prolong the QT interval or PR interval to any clinically relevant extent.
Pharmacokinetics
Adults
Absorption
Raltegravir, given 400 mg twice daily, is absorbed with a Tmax of approximately 3 hours postdose in the fasted state in healthy subjects. Raltegravir 1200 mg once daily is rapidly absorbed with median Tmax of ~1.5 to 2 hours in the fasted state.
Raltegravir increases dose proportionally (AUC and Cmax) or slightly less than dose proportionally (C12hr) over the dose range 100 mg to 1600 mg.
The absolute bioavailability of raltegravir has not been established. The chewable tablet and oral suspension have higher oral bioavailability compared to the 400 mg film-coated tablet.
Relative to the raltegravir 400 mg formulation, the raltegravir 600 mg formulation has higher relative bioavailability.
Steady-state is generally reached in 2 days, with little to no accumulation with multiple dose administration for the 400 mg twice daily and 1200 once daily formulation.
Effect of Food on Oral Absorption
The food effect of various formulations are presented in Table 12.
Table 12: Effect of Food on the Pharmacokinetics of Raltegravir Formulations
|
PK parameter ratio (fed/fasted) |
Formulation |
Meal Type |
AUC Ratio
(90% CI) |
Cmax Ratio
(90% CI) |
Cmin Ratio
(90% CI) |
400 mg twice daily |
Low Fat |
0.54 (0.41-0.71) |
0.48 (0.35-0.67) |
0.86 (0.54-1.36) |
Moderate Fat |
1.13 (0.85-1.49) |
1.05 (0.75-1.46) |
1.66 (1.04-2.64) |
High Fat |
2.11 (1.60-2.80) |
1.96 (1.41-2.73) |
4.13 (2.60-6.57) |
1200 mg once daily |
Low Fat |
0.58 (0.46-0.74) |
0.48 (0.37-0.62) |
0.84 (0.63-1.10) |
High Fat |
1.02 (0.86-1.21) |
0.72 (0.58-0.90) |
0.88 (0.66-1.18) |
Chewable tablet |
High Fat |
0.94 (0.78-1.14) |
0.38 (0.28-0.52) |
2.88 (2.21-3.75) |
Oral suspension |
The effect of food on oral suspension was not studied. |
Low-fat meal: 300 Kcal, 2.5 g fat
Moderate-fat meal: 600 Kcal, 21 g fat
High-fat meal: 825 Kcal, 52 g fat |
Distribution
Raltegravir is approximately 83% bound to human plasma protein over the concentration range of 2 to 10 μM.
In one study of HIV-1 infected subjects who received raltegravir 400 mg twice daily, raltegravir was measured in the cerebrospinal fluid. In the study (n=18), the median cerebrospinal fluid concentration was 5.8% (range 1 to 53.5%) of the corresponding plasma concentration. This median proportion was approximately 3-fold lower than the free fraction of raltegravir in plasma. The clinical relevance of this finding is unknown.
Metabolism And Excretion
The apparent terminal half-life of raltegravir is approximately 9 hours, with a shorter α-phase half-life (~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 raltegravirglucuronide,
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. The major mechanism of clearance of raltegravir in humans is UGT1A1-mediated glucuronidation.
Table 13: Multiple-Dose Pharmacokinetic Parameters of Raltegravir Following the Administration of 400 mg Twice Daily and 1200 mg Once Daily in HIV-infected Subjects
Parameter |
400 mg BID
Geometric Mean (%CV)
N=6 |
1200 mg QD
Geometric Mean (%CV)
N=524 |
AUC (μM•hr) |
AUC 0-12= 14.3 (88.6) |
AUC0-24 = 55.3 (41.5) |
Cmax (μM) |
4.5 (128) |
15.7 (45.8) |
Cmin (nM) |
C12= 142 (63.8) |
C24 = 107 (97.5) |
Special Populations
Pediatric
ISENTRESS
Two pediatric formulations were evaluated in healthy adult volunteers, where the chewable tablet and oral suspension were compared to the 400 mg tablet. The chewable tablet and oral suspension demonstrated higher oral bioavailability, thus higher AUC, compared to the 400 mg tablet. In the same study, the oral suspension resulted in higher oral bioavailability compared to the chewable tablet. These observations resulted in proposed pediatric doses targeting 6 mg/kg/dose for the chewable tablets and oral suspension. As displayed in Table 13, the doses recommended for HIV-infected infants, children and adolescents 4 weeks to 18 years of age [see DOSAGE AND ADMINISTRATION] resulted in a pharmacokinetic profile of raltegravir similar to that observed in adults receiving 400 mg twice daily.
Overall, dosing in pediatric patients achieved exposures (Ctrough) above 45 nM in the majority of subjects, but some differences in exposures between formulations were observed. Pediatric patients above 25 kg administered the chewable tablets had lower trough concentrations (113 nM) compared to pediatric patients above 25 kg administered the 400 mg tablet formulation (233 nM) [see Clinical Studies]. As a result, the 400 mg film-coated tablet is the recommended dose in patients weighing at least 25 kg; however, the chewable tablet offers an alternative regimen in patients weighing at least 25 kg who are unable to swallow the film-coated tablet [see DOSAGE AND ADMINISTRATION]. In addition, pediatric patients weighing 11 to 25 kg who were administered the chewable tablets had the lowest trough concentrations (82 nM) compared to all other pediatric subgroups.
Table 14: Raltegravir Steady State Pharmacokinetic Parameters in Pediatric Patients Following Administration of Recommended Twice-Daily Doses
Body Weight |
Formulation |
Dose |
N* |
Geometric Mean
(%CV†)
AUC0-12hr (μM•hr) |
Geometric Mean
(%CV†)
C12hr (nM) |
≥25 kg |
Film-coated
tablet |
400 mg twice daily |
18 |
14.1 (121%) |
233 (157%) |
≥25 kg |
Chewable
tablet |
Weight based dosing,
see Table 3 |
9 |
22.1 (36%) |
113 (80%) |
11 to less than
25 kg |
Chewable
tablet |
Weight based dosing,
see Table 4 |
13 |
18.6 (68%) |
82 (123%) |
3 to less than
20 kg |
Oral
suspension |
Weight based dosing,
see Table 4 |
19 |
24.5 (43%) |
113 (69%) |
*Number of patients with intensive pharmacokinetic (PK) results at the final recommended dose.
†Geometric coefficient of variation. |
Elimination of raltegravir in vivo in human is primarily through the UGT1A1-mediated glucuronidation pathway. UGT1A1 catalytic activity is negligible at birth and matures after birth. The dose recommended for neonates less than 4 weeks of age takes into consideration the rapidly increasing UGT1A1 activity and drug clearance from birth to 4 weeks of age. Table 15 displays pharmacokinetic parameters for neonates receiving the granules for oral suspension at the recommended dose [see DOSAGE AND ADMINISTRATION].
Table 15: Raltegravir Pharmacokinetic Parameters from IMPAACT P1110 Following Age and Weight Based Dosing of Oral Suspension
Age (hours/days) at PK Sampling |
Dose (See Table 5) |
N* |
Geometric Mean
(%CV†)
AUC (μM•hr ) |
Geometric Mean
(%CV†)
Ctrough (nM) |
Birth - 48 hours |
1.5 mg/kg once daily |
25 |
85.9 (38.4%)‡ |
2132.9 (64.2%)‡ |
15 to 18 days |
3.0 mg/kg twice daily |
23 |
32.2 (43.3%)‡ |
1255.5 (83.7%)‡ |
*Number of patients with intensive pharmacokinetic (PK) results at the final recommended dose.
†Geometric coefficient of variation.
‡ AUC 0-24hr (N = 24) and C24hr
§AUC 0-12hr and C12hr |
ISENTRESS HD
ISENTRESS HD 1200 mg (2 x 600 mg) was not evaluated in a pediatric clinical study. Exposures for pediatric subjects weighing at least 40 kg administered ISENTRESS HD are predicted to be comparable to adult exposures observed from Phase III ONCEMRK.
Age/Race/Gender
There is no clinically meaningful effect of age (18 years and older), race, or gender on the pharmacokinetics of raltegravir.
Hepatic Impairment
Raltegravir is eliminated primarily by glucuronidation in the liver. The pharmacokinetics of a single 400-mg dose of raltegravir were not altered in patients with moderate (Child-Pugh Score 7 to 9) hepatic impairment.
No hepatic impairment study has been conducted with ISENTRESS HD 1200 mg (2 x 600 mg) once daily.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. The pharmacokinetics of a single 400-mg dose of raltegravir were not altered in patients with severe (24-hour creatinine clearance of <30 mL/min/1.73 m2) renal impairment.
No renal impairment study was conducted with ISENTRESS HD 1200 mg (2 x 600 mg) once daily.
The extent to which ISENTRESS may be dialyzable is unknown.
Drug Interactions
In vitro, raltegravir does not inhibit (IC50>100 μM) CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 or CYP3A. In vivo, raltegravir does not inhibit CYP3A4. Moreover, in vitro, raltegravir did not induce CYP1A2, CYP2B6 or CYP3A4. Similarly, raltegravir is not an inhibitor (IC50>50 μM) of UGT1A1 or UGT2B7, and raltegravir does not inhibit P-glycoprotein-mediated transport.
Raltegravir drug interaction study results are shown in Tables 16 and 17. For information regarding clinical recommendations [see DRUG INTERACTIONS].
Table 16: Effect of Other Agents on the Pharmacokinetics of Raltegravir in Adults
Coadministered
Drug |
Coadministered
Drug
Dose/Schedule |
Raltegravir
Dose/Schedule |
Ratio (90% Confidence Interval) of Raltegravir Pharmacokinetic Parameters with/without Coadministered
Drug;
No Effect = 1.00 |
n |
Cmax |
AUC |
Cmin |
class="EmphTd">
aluminum and magnesium hydroxide antacid* |
20 mL single dose given with raltegravir |
400 mg twice daily |
25 |
0.56 (0.42, 0.73) |
0.51 (0.40, 0.65) |
0.37 (0.29, 0.48) |
|
20 mL single dose given 2 hours before raltegravir |
|
23 |
0.49 (0.33, 0.71) |
0.49 (0.35, 0.67) |
0.44 (0.34, 0.55) |
|
20 mL single dose given 2 hours after raltegravir |
|
23 |
0.78 (0.53, 1.13) |
0.70 (0.50, 0.96) |
0.43 (0.34, 0.55) |
|
20 mL single dose given 4 hours before raltegravir |
|
17 |
0.78 (0.55, 1.10) |
0.81 (0.63, 1.05) |
0.40 (0.31, 0.52) |
|
20 mL single dose given 4 hours after raltegravir |
|
18 |
0.70 (0.48, 1.04) |
0.68 (0.50, 0.92) |
0.38 (0.30, 0.49) |
|
20 mL single dose given 6 hours before raltegravir |
|
16 |
0.90 (0.58, 1.40) |
0.87 (0.64, 1.18) |
0.50 (0.39, 0.65) |
|
20 mL single dose given 6 hours after raltegravir |
|
16 |
0.90 (0.58, 1.41) |
0.89 (0.64, 1.22) |
0.51 (0.40, 0.64) |
aluminum and magnesium hydroxide antacid* |
20 mL single dose given 12 hours after raltegravir |
1200 mg single dose |
19 |
0.86 (0.65, 1.15) |
0.86 (0.73, 1.03) |
0.42 (0.34, 0.52) |
atazanavir |
400 mg daily |
100 mg single dose |
10 |
1.53 (1.11, 2.12) |
1.72 (1.47, 2.02) |
1.95 (1.30, 2.92) |
atazanavir |
400 mg daily |
1200 mg single dose |
14 |
1.16 (1.01, 1.33) |
1.67 (1.34, 2.10) |
1.26 (1.08, 1.46) |
atazanavir/ritonavir |
300 mg/100 mg daily |
400 mg twice daily |
10 |
1.24 (0.87, 1.77) |
1.41 (1.12, 1.78) |
1.77 (1.39, 2.25) |
boceprevir |
800 mg three times daily |
400 mg single dose |
22 |
1.11 (0.91-1.36) |
1.04 (0.88-1.22) |
0.75 (0.45-1.23) |
calcium carbonate antacid* |
3000 mg single dose given with raltegravir |
400 mg twice daily |
24 |
0.48 (0.36, 0.63) |
0.45 (0.35, 0.57) |
0.68 (0.53, 0.87) |
calcium carbonate antacid* |
3000 mg single dose given with raltegravir |
1200 mg single dose |
19 |
0.26 (0.21, 0.32) |
0.28 (0.24, 0.32) |
0.52 (0.45, 0.61) |
|
3000 mg single dose given 12 hours after raltegravir |
|
|
0.98 (0.81, 1.17) |
0.90 (0.80, 1.03) |
0.43 (0.36, 0.51) |
efavirenz |
600 mg daily |
400 mg single dose |
9 |
0.64 (0.41, 0.98) |
0.64 (0.52, 0.80) |
0.79 (0.49, 1.28) |
efavirenz |
600 mg daily |
1200 mg single dose |
21 |
0.91 (0.70, 1.17) |
0.86 (0.73, 1.01) |
0.94 (0.76, 1.17) |
etravirine |
200 mg twice daily |
400 mg twice daily |
19 |
0.89 (0.68, 1.15) |
0.90 (0.68, 1.18) |
0.66 (0.34, 1.26) |
omeprazole* |
20 mg daily |
400 mg twice daily |
18 |
1.51 (0.98, 2.35) |
1.37 (0.99, 1.89) |
1.24 (0.95, 1.62) |
|
|
|
| | | |
rifampin |
600 mg daily |
400 mg single dose |
9 |
0.62 (0.37, 1.04) |
0.60 (0.39, 0.91) |
0.39 (0.30, 0.51) |
rifampin |
600 mg daily |
400 mg twice daily when administered alone; 800 mg twice daily when administered with
rifampin |
14 |
1.62 (1.12, 2.33) |
1.27 (0.94, 1.71) |
0.47 (0.36, 0.61) |
ritonavir |
100 mg twice
daily |
400 mg single
dose |
10 |
0.76
(0.55, 1.04) |
0.84
(0.70, 1.01) |
0.99
(0.70, 1.40) |
tenofovir disoproxil
fumarate |
300 mg daily |
400 mg twice daily |
9 |
1.64
(1.16, 2.32) |
1.49
(1.15, 1.94) |
1.03
(0.73, 1.45) |
tipranavir/ritonavir |
500 mg/200 mg
twice daily |
400 mg twice daily |
15
(14
for
Cmin) |
0.82
(0.46, 1.46) |
0.76
(0.49, 1.19) |
0.45
(0.31, 0.66) |
*Study conducted in HIV-infected subjects. |
Table 17: Effect of Raltegravir on the Pharmacokinetics of Other Agents in Adults
Substrate Drug |
Raltegravir
Dose/Schedule |
Ratio (90% Confidence Interval) of Substrate Pharmacokinetic Parameters with/without Coadministered Drug;
No Effect = 1.00 |
n |
Cmax |
AUC |
Cmin |
Tenofovir disoproxil
fumarate 300 mg |
400 mg |
9 |
0.77 (0.69,
0.85) |
0.90 (0.82,
0.99) |
C24hr
0.87 (0.74, 1.02) |
Etravirine 200 mg |
400 mg |
19 |
1.04 (0.97,
1.12) |
1.10 (1.03,
1.16) |
1.17 (1.10, 1.26) |
In drug interaction studies, there was no effect of raltegravir on the PK of ethinyl estradiol, methadone, midazolam or boceprevir.
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 α, β, and γ.
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, 5 clinical isolates of HIV-1 subtype B had EC95 values ranging from 9 to 19 nM in cultures of mitogen-activated human peripheral blood mononuclear cells. In a single-cycle infection assay, raltegravir inhibited infection of 23 HIV-1 isolates representing 5 non-B subtypes (A, C, D, F, and G) and 5 circulating recombinant forms (AE, AG, BF, BG, and cpx) with EC50 values ranging from 5 to 12 nM. Raltegravir also inhibited replication of an HIV-2 isolate when tested in CEMx174 cells (EC95 value = 6 nM). No antagonism 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, 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 Y143 (changed to C, H, or R) or Q148 (changed to H, K, or R) or N155 (changed to H) plus one or more additional substitutions (i.e., L74M, E92Q, Q95K/R, T97A, E138A/K, G140A/S, V151I, G163R, H183P, Y226C/D/F/H, S230R, and D232N). E92Q, T97A, and F121C are occasionally seen in the absence of substitutions at Y143, Q148, or N155 in raltegravir-treatment failure subjects.
treatment-naive Adult Subjects:
By Week 240 in the STARTMRK trial, the primary raltegravir resistance-associated substitutions were observed in 4 (2 with Y143H/R and 2 with Q148H/R) of the 12 virologic failure subjects with evaluable genotypic data from paired baseline and raltegravir treatment-failure isolates. By Week 96 in the ONCEMRK trial, primary raltegravir resistance substitutions were observed in on treatment isolates obtained from 4 (3 with N155H and 1 with E92Q) of 14 virologic failure subjects with evaluable genotypic data in the 1,200 mg QD arm and 2 (1 with N155H and 1 with T97A) of 6 virologic failure subjects in the 400 mg BID arm. Additional integrase substitutions observed included L74M, Q95K, V151I, E170A, I203M, and D232N. These resistant isolates exhibited 6.2-to 19-fold reductions in susceptibility to raltegravir. Overall, at Week 96, detection of raltegravir resistance was not different between the QD and BID arms in subjects who were failing treatment and had resistance data evaluable (28.6% versus 33.3%, respectively).
Treatment-Experienced Adult Subjects:
By Week 96 in the BENCHMRK trials, at least one of the primary raltegravir resistance-associated substitutions, Y143C/H/R, Q148H/K/R, and N155H, was observed in 76 of the 112 virologic failure subjects with evaluable genotypic data from paired baseline and raltegravir treatment-failure isolates. The emergence of the primary raltegravir resistance-associated substitutions was observed cumulatively in 70 subjects by Week 48 and 78 subjects by Week 96, 15.2% and 17% of the raltegravir recipients, respectively. Some (n=58) of those HIV-1 isolates harboring one or more of the primary raltegravir resistance-associated substitutions were evaluated for raltegravir susceptibility yielding a median decrease of 26.3-fold (mean 48.9 ± 44.8-fold decrease, ranging from 0.8-to 159-fold) compared to the wild-type reference.
Cross Resistance
Cross resistance has been observed among HIV-1 integrase strand transfer inhibitors (INSTIs). Amino acid substitutions in HIV-1 integrase conferring resistance to raltegravir generally also confer resistance to elvitegravir. Substitutions at amino acid Y143 confer greater reductions in susceptibility to raltegravir than to elvitegravir, and the E92Q substitution confers greater reductions in susceptibility to elvitegravir than to raltegravir. Viruses harboring a substitution at amino acid Q148, along with one or more other raltegravir resistance substitutions, may also have clinically significant resistance to dolutegravir.
Pharmacogenomics
UGT1A1 Polymorphism
There is no evidence that common UGT1A1 polymorphisms alter raltegravir pharmacokinetics to a clinically meaningful extent. In a comparison of 30 adult subjects with *28/*28 genotype (associated with reduced activity of UGT1A1) to 27 adult subjects with wild-type genotype, the geometric mean ratio (90% CI) of AUC was 1.41 (0.96, 2.09).
In the neonatal study IMPAACT P1110, there was no association between apparent clearance (CL/F) of raltegravir and UGT 1A1 genotype polymorphisms.
Clinical Studies
Description Of Clinical Studies
The evidence of durable efficacy of ISENTRESS 400 mg twice daily is based on the analyses of 240week
data from a randomized, double-blind, active-controlled trial, STARTMRK evaluating ISENTRESS 400 mg twice daily in antiretroviral treatment-naive HIV-1 infected adult subjects, the analysis of 96-week data from a randomized, double-blind, active-control trial, ONCEMRK evaluating ISENTRESS HD 1200 mg (2 x 600 mg) once daily in treatment-naive adult subjects, and 96-week data from 2 randomized, double-blind, placebo-controlled studies, BENCHMRK 1 and BENCHMRK 2, evaluating ISENTRESS 400 mg twice daily in antiretroviral treatment-experienced HIV-1 infected adult subjects. See Table 18.
Table 18: Trials Conducted with ISENTRESS and ISENTRESS HD in Subjects with HIV-1 Infection
Trial |
Study Type |
Population |
Study Arms (N) |
Dose/Formulation |
Timepoint |
STARTMRK |
Randomized, double
blind, active-controlled |
Treatment-
Naive Adults |
ISENTRESS 400 mg
Twice Daily (281)
Efavirenz 600 mg At Bedtime (282)
Both in combination with emtricitabine (+)
tenofovir disoproxil
fumarate |
400 mg film-coated tablet |
Week 240 |
ONCEMRK |
Randomized, double
blind, active-controlled |
Treatment-
Naive Adults |
ISENTRESS HD 1200
mg Once Daily (531)
ISENTRESS 400 mg Twice Daily (266)
Both in combination with emtricitabine (+)
tenofovir disoproxil
fumarate |
600 mg film-coated tablet
400 mg film-coated tablet |
Week 96 |
BENCHMRK 1 |
Randomized, double
blind, placebo-controlled |
Treatment-
Experienced
Adults |
ISENTRESS 400 mg
Twice Daily (232)
Placebo (118)
Both in combination
with optimized background therapy |
400 mg film-coated tablet |
Week 240
(Week 156 on
double-blind
plus Week 84
on open-label) |
BENCHMRK 2 |
Randomized, double
blind, placebo-controlled |
Treatment-
Experienced
Adults |
ISENTRESS 400 mg
Twice Daily (230)
Placebo (119)
Both in combination
with optimized background therapy |
400 mg film-coated tablet |
Week 240
(Week 156 on
double-blind
plus Week 84
on open-label) |
IMPAACT
P1066 |
Open-label, non
comparative |
Pediatric
Patients - 4
weeks to 18
years of age (Treatment-
Experienced or Failed Prior PMTCT) |
ISENTRESS 400 mg
tablet Twice Daily - 12 to 18
years or 6 to <12
years and ≥25 kg (87)
ISENTRESS chewable
tablet- Weight-Based
Dose to Approximate 6
mg/kg Twice Daily - 2 to <12 years (39)
ISENTRESS for oral
suspension- Weight-Based Dose to
Approximate 6 mg/kg
Twice Daily - 4 weeks to <2 years (26)
In combination with optimized background therapy |
400 mg film-coated tablet
25 mg and 100 mg chewable tablet
100 mg sachet for oral suspension |
Week 240 |
treatment-naive Adult Subjects
STARTMRK (ISENTRESS 400 mg Twice Daily)
STARTMRK is a Phase 3 randomized, international, double-blind, active-controlled trial to evaluate the safety and efficacy of ISENTRESS 400 mg twice daily versus efavirenz 600 mg at bedtime both with emtricitabine (+) tenofovir disoproxil fumarate in treatment-naive HIV-1-infected subjects with HIV-1 RNA >5000 copies/mL. Randomization was stratified by screening HIV-1 RNA level (≤50,000 copies/mL; or >50,000 copies/mL) and by hepatitis status. In STARTMRK, 563 subjects were randomized and received at least 1 dose of either raltegravir 400 mg twice daily or efavirenz 600 mg at bedtime, both in combination with emtricitabine (+) tenofovir disoproxil fumarate. There were 563 subjects included in the efficacy and safety analyses. At baseline, the median age of subjects was 37 years (range 19-71), 19% female, 58% non-white, 6% had hepatitis B and/or C virus co-infection, 20% were CDC Class C (AIDS), 53% had HIV1
RNA greater than 100,000 copies per mL, and 47% had CD4+ cell count less than 200 cells per mm3; the frequencies of these baseline characteristics were similar between treatment groups.
ONCEMRK (ISENTRESS HD 1200 mg [2 x 600 mg] Once Daily)
ONCEMRK is a Phase 3 randomized, international, double-blind, active-controlled trial to evaluate the safety and efficacy of ISENTRESS HD 1200 mg (2 x 600 mg) once daily versus ISENTRESS 400 mg twice daily, both in combination with emtricitabine (+) tenofovir disoproxil fumarate, in treatment-naive HIV-1-infected subjects with HIV-1 RNA ≥1000 copies/mL. Randomization was stratified by screening HIV-1 RNA level (≤100,000 or >100,000 copies/mL) and by hepatitis B and C infection status.
In ONCEMRK, 797 subjects were randomized and received at least 1 dose of either raltegravir 1200 mg once daily or raltegravir 400 mg twice daily, both in combination with emtricitabine (+) tenofovir disoproxil fumarate. There were 797 subjects included in the efficacy and safety analyses. At baseline, the median age of subjects was 34 years (range 18-84), 15% female, 41% non-white, 3% had hepatitis B and/or C virus co-infection, 13% were CDC Class C (AIDS), 28% had HIV-1 RNA greater than 100,000
copies per mL, and 13% had CD4+ cell count less than 200 cells per mm3; the frequencies of these baseline characteristics were similar between treatment groups. Table 19 shows the virologic outcomes in both studies. Side-by-side tabulation is to simplify presentation; direct comparisons across trials should not be made due to differing duration of follow-up.
Table 19: Virologic Outcomes of Randomized Treatment in STARTMRK and ONCEMRK (Snapshot Algorithm) in HIV treatment-naive Adults
|
STARTMRK
Week 240 |
ONCEMRK
Week 96 |
ISENTRESS
400 mg Twice Daily (N=281) |
Efavirenz
600 mg At
Bedtime
(N=282) |
ISENTRESS HD
1200 mg Once Daily
(N=531) |
ISENTRESS
400 mg Twice Daily (N=266) |
HIV RNA < Lower Limit of
Quantitation* |
66% |
60% |
82% |
80% |
Treatment Difference |
6.6% (95% CI: -1.4%, 14.5%) |
1.4% (95% CI: -4.4%, 7.3%) |
HIV RNA ≥ Lower Limit of
Quantitation |
8% |
15% |
9% |
8% |
No Virologic Data at Analysis
Timepoint |
26% |
26% |
9% |
12% |
Reasons |
|
|
|
Discontinued trial due to
AE or Death† |
5% |
10% |
1% |
3% |
Discontinued trial for Other
Reasons‡ |
15% |
14% |
7% |
8% |
On trial but missing data at
timepoint |
6% |
2% |
1% |
2% |
Notes: ISENTRESS BID, ISENTRESS HD and Efavirenz were administered with emtricitabine (+) tenofovir disoproxil fumarate
*Lower Limit of Quantitation: STARTMRK <50 copies/mL; ONCEMRK < 40 copies/mL.
† Includes subjects who discontinued because of adverse event (AE) or death at any time point from Day 1 through the time window if this resulted in no virologic data on treatment during the specified window.
‡Other Reasons includes: lost to follow-up, moved, non-compliance with study drug, physician decision, pregnancy, withdrawal by subject. |
In the ONCEMRK trial, ISENTRESS HD 1200 mg (2 x 600 mg) once daily demonstrated consistent virologic and immunologic efficacy relative to ISENTRESS 400 mg twice daily, both in combination with emtricitabine (+) tenofovir disoproxil fumarate, across demographic and baseline prognostic factors, including: baseline HIV RNA levels >100,000 copies/mL and demographic groups (including age, gender, race, ethnicity and region), concomitant proton pump inhibitors/H2 blockers use and viral subtypes (comparing non-clade B as a group to clade B).
Consistent efficacy in subjects receiving ISENTRESS HD 1200 mg (2 x 600 mg) once daily was observed across HIV subtypes with 80.6% (270/335) and 83.5% (162/194) of subjects with B and non-B subtypes respectively, achieving HIV RNA <40 copies/mL at week 96 (Snapshot approach).
Treatment-Experienced Adult Subjects
BENCHMRK 1 and BENCHMRK 2 are Phase 3 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-1-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 20 shows the demographic characteristics of subjects in the group receiving ISENTRESS 400 mg twice daily and subjects in the placebo group.
Table 20: Trials BENCHMRK 1 and BENCHMRK 2 Baseline Characteristics
Randomized Studies BENCHMRK 1 and BENCHMRK 2 |
ISENTRESS 400 mg Twice
Daily + OBT
(N = 462) |
Placebo + OBT
(N = 237) |
Gender |
Male |
88% |
89% |
Female |
12% |
11% |
Race |
White |
65% |
73% |
Black |
14% |
11% |
Asian |
3% |
3% |
Hispanic |
11% |
8% |
Others |
6% |
5% |
Age (years) |
Median (min, max) |
45 (16 to 74) |
45 (17 to 70) |
CD4+ Cell Count |
Median (min, max), cells/mm3 |
119 (1 to 792) |
123 (0 to 759) |
≤50 cells/mm3 |
32% |
33% |
>50 and ≤200 cells/mm3 |
37% |
36% |
Plasma HIV-1 RNA |
|
|
Median (min, max), log10 copies/mL |
4.8 (2 to 6) |
4.7 (2 to 6) |
>100,000 copies/mL
|
36% |
33% |
History of AIDS |
Yes |
92% |
91% |
Prior Use of ART, Median (1st Quartile, 3rd Quartile) |
Years of ART Use |
10 (7 to 12) |
10 (8 to 12) |
Number of ART |
12 (9 to 15) |
12 (9 to 14) |
Hepatitis Co-infection* |
No Hepatitis B or C virus |
83% |
84% |
Hepatitis B virus only |
8% |
3% |
Hepatitis C virus only |
8% |
12% |
Co-infection of Hepatitis B and C |
1% |
1% |
virus |
|
|
Stratum |
Enfuvirtide in OBT |
38% |
38% |
Resistant to ≥2 PI |
97% |
95% |
*Hepatitis B virus surface antigen positive or hepatitis C virus antibody positive. |
Table 21 compares the characteristics of optimized background therapy at baseline in the group receiving ISENTRESS 400 mg twice daily and subjects in the control group.
Table 21: Trials BENCHMRK 1 and BENCHMRK 2 Characteristics of Optimized Background Therapy at Baseline
Randomized Studies
BENCHMRK 1 and BENCHMRK 2 |
ISENTRESS 400 mg Twice Daily + OBT
(N = 462) |
Placebo + OBT
(N = 237) |
Number of ARTs in OBT |
|
|
Median (min, max) |
4 (1 to 7) |
4 (2 to 7) |
Number of Active PI in OBT by Phenotypic
Resistance Test* |
|
|
0 |
36% |
41% |
1 or more |
60% |
58% |
Phenotypic Sensitivity Score (PSS)† |
|
|
0 |
15% |
18% |
1 |
31% |
30% |
2 |
31% |
28% |
3 or more |
18% |
20% |
Genotypic Sensitivity Score (GSS)† |
|
|
0 |
25% |
27% |
1 |
38% |
40% |
2 |
24% |
21% |
3 or more |
11% |
10% |
*Darunavir use in OBT in darunavir-naïve 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-naïve subjects was counted as one active drug in OBT in the GSS and PSS. Similarly, darunavir use in OBT in darunavir-naïve subjects was counted as one active drug in OBT. |
Week 96 outcomes for the 699 subjects randomized and treated with the recommended dose of ISENTRESS 400 mg twice daily or placebo in the pooled BENCHMRK 1 and 2 studies are shown in Table 22.
Table 22: Virologic Outcomes of Randomized Treatment of
BENCHMRK 1 and BENCHMRK 2 Trials at 96 Weeks (Pooled Analysis)
|
ISENTRESS
400 mg Twice Daily + OBT
(N = 462) |
Placebo + OBT
(N = 237) |
Subjects with HIV-1 RNA less
than 50 copies/mL |
55% |
27% |
Virologic Failure* |
35% |
66% |
No virologic data at Week 96
Window |
|
|
Reasons
Discontinued study due to
AE or death† |
3% |
3% |
Discontinued study for other reasons‡ |
4% |
4% |
Missing data during window but on study |
4% |
<1% |
*Includes subjects who switched to open-label raltegravir after Week 16 due to the protocol-defined virologic failure, subjects who discontinued prior to Week 96 for lack of efficacy, subjects changed OBT due to lack of efficacy prior to Week 96, or subjects who were ≥50 copies in the 96 week window.
†Includes subjects who discontinued due to AE or death at any time point from Day 1 through the Week 96 window if this resulted in no virologic data on treatment during the Week 96 window.
‡Other includes: withdrew consent, loss to follow-up, moved etc., if the viral load at the time of discontinuation was <50 copies/mL. |
The mean changes in CD4 count from baseline were 118 cells/mm3 in the group receiving ISENTRESS 400 mg twice daily and 47 cells/mm3 for the control group.
Treatment-emergent CDC Category C events occurred in 4% of the group receiving ISENTRESS 400 mg twice daily and 5% of the control group.
Virologic responses at Week 96 by baseline genotypic and phenotypic sensitivity score are shown in Table 23.
Table 23: Virologic Response at 96 Week Window by Baseline
Genotypic/Phenotypic Sensitivity Score
|
Percent with HIV-1 RNA <50 copies/mL
At Week 96 |
n |
ISENTRESS
400 mg
Twice Daily + OBT
(N = 462) |
n |
Placebo
+ OBT
(N = 237) |
Phenotypic Sensitivity Score (PSS)* |
0 |
67 |
43 |
43 |
5 |
1 |
144 |
58 |
71 |
23 |
2 |
142 |
61 |
66 |
32 |
3 or more |
85 |
48 |
48 |
42 |
Genotypic Sensitivity Score (GSS)* |
0 |
116 |
39 |
65 |
5 |
1 |
177 |
62 |
95 |
26 |
2 |
111 |
61 |
49 |
53 |
3 or more |
51 |
49 |
23 |
35 |
*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-naïve subjects was counted as one active drug in OBT in the GSS and PSS. Similarly, darunavir use in OBT in darunavir-naïve subjects was counted as one active drug in OBT. |
Switch of Suppressed Subjects from Lopinavir (+) Ritonavir to Raltegravir
The SWITCHMRK 1 & 2 Phase 3 studies evaluated HIV-1 infected subjects receiving suppressive therapy (HIV-1 RNA <50 copies/mL on a stable regimen of lopinavir 200 mg (+) ritonavir 50 mg 2 tablets twice daily plus at least 2 nucleoside reverse transcriptase inhibitors for >3 months) and randomized them
1:1 to either continue lopinavir (+) ritonavir (n=174 and n=178, SWITCHMRK 1 & 2, respectively) or replace lopinavir (+) ritonavir with ISENTRESS 400 mg twice daily (n=174 and n=176, respectively). The primary virology endpoint was the proportion of subjects with HIV-1 RNA less than 50 copies/mL at Week 24 with a prespecified non-inferiority margin of -12% for each study; and the frequency of adverse events up to 24 weeks.
Subjects with a prior history of virological failure were not excluded and the number of previous antiretroviral therapies was not limited.
These studies were terminated after the primary efficacy analysis at Week 24 because they each failed to demonstrate non-inferiority of switching to ISENTRESS versus continuing on lopinavir (+) ritonavir. In the combined analysis of these studies at Week 24, suppression of HIV-1 RNA to less than 50 copies/mL was maintained in 82.3% of the ISENTRESS group versus 90.3% of the lopinavir (+) ritonavir group. Clinical and laboratory adverse events occurred at similar frequencies in the treatment groups.
Pediatric Subjects
2 To 18 Years Of Age
IMPAACT P1066 is a Phase I/II open label multicenter trial to evaluate the pharmacokinetic profile, safety, tolerability, and efficacy of raltegravir in HIV infected children. This study enrolled 126 treatment experienced children and adolescents 2 to 18 years of age. Subjects were stratified by age, enrolling adolescents first and then successively younger children. Subjects were enrolled into cohorts according to age and received the following formulations: Cohort I (12 to less than 18 years old), 400 mg film-coated tablet; Cohort IIa (6 to less than 12 years old), 400 mg film-coated tablet; Cohort IIb (6 to less than 12 years old), chewable tablet; Cohort III (2 to less than 6 years), chewable tablet. Raltegravir was administered with an optimized background regimen.
The initial dose finding stage included intensive pharmacokinetic evaluation. Dose selection was based upon achieving similar raltegravir plasma exposure and trough concentration as seen in adults, and acceptable short term safety. After dose selection, additional subjects were enrolled for evaluation of long term safety, tolerability and efficacy. Of the 126 subjects, 96 received the recommended dose of ISENTRESS [see DOSAGE AND ADMINISTRATION].
These 96 subjects had a median age of 13 (range 2 to 18) years, were 51% Female, 34% Caucasian, and 59% Black. At baseline, mean plasma HIV-1 RNA was 4.3 log10 copies/mL, median CD4 cell count was 481 cells/mm3 (range: 0 – 2361) and median CD4% was 23.3% (range: 0 – 44). Overall, 8% had baseline plasma HIV-1 RNA >100,000 copies/mL and 59% had a CDC HIV clinical classification of category B or C. Most subjects had previously used at least one NNRTI (78%) or one PI (83%).
Ninety-three (97%) subjects 2 to 18 years of age completed 24 weeks of treatment (3 discontinued due to non-compliance). At Week 24, 54% achieved HIV RNA <50 copies/mL; 66% achieved HIV RNA <400 copies/mL. The mean CD4 count (percent) increase from baseline to Week 24 was 119 cells/mm3 (3.8%).
4 Weeks To Less Than 2 Years Of Age
IMPAACT P1066 also enrolled HIV-infected, infants and toddlers 4 weeks to less than 2 years of age (Cohorts IV and V) who had received prior antiretroviral therapy either as prophylaxis for prevention of mother-to-child transmission (PMTCT) and/or as combination antiretroviral therapy for treatment of HIV infection. Raltegravir was administered as an oral suspension without regard to food in combination with an optimized background regimen.
The 26 subjects had a median age of 28 weeks (range: 4 -100), were 35% female, 85% Black and 8% Caucasian. At baseline, mean plasma HIV-1 RNA was 5.7 log10 copies/mL (range: 3.1 – 7), median CD4
cell count was 1400 cells/mm3 (range: 131 – 3648) and median CD4% was 18.6% (range: 3.3 – 39.3). Overall, 69% had baseline plasma HIV-1 RNA exceeding 100,000 copies/mL and 23% had a CDC HIV clinical classification of category B or C. None of the 26 subjects were completely treatment naïve. All infants under 6 months of age had received nevirapine or zidovudine for prevention of mother-to-infant transmission, and 43% of subjects greater than 6 months of age had received two or more antiretrovirals.
Of the 26 treated subjects, 23 subjects were included in the Week 24 and 48 efficacy analyses, respectively. All 26 treated subjects were included for safety analyses.
At Week 24, 39% achieved HIV RNA <50 copies/mL and 61% achieved HIV RNA <400 copies/mL. The mean CD4 count (percent) increase from baseline to Week 24 was 500 cells/mm3 (7.5%).
At Week 48, 44% achieved HIV RNA <50 copies/mL and 61% achieved HIV RNA <400 copies/mL. The mean CD4 count (percent) increase from baseline to Week 48 was 492 cells/mm3 (7.8%).