Intelence

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to INTELENCE during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.

Risk Summary

Prospective pregnancy data from clinical trials and the APR are not sufficient to adequately assess the risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Etravirine use during pregnancy has been evaluated in a limited number of individuals as reported by the APR, and available data show 1 birth defect in 66 first trimester exposures to etravirine-containing regimens (see Data) .

The estimated background rate for major birth defects is 2.7% in the U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15–20%. The background risk of major birth defects and miscarriage for the indicated population is unknown.

In animal reproduction studies, no adverse developmental effects were observed with orally administered etravirine at exposures equivalent to those at the maximum recommended human dose (MRHD) of 400 mg daily (see Data) .

Data

Risk Summary

The Centers for Disease Control and Prevention recommend that HIV-1-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV.

Based on limited data, etravirine has been shown to be present in human breast milk. There are no data on the effects of etravirine on the breastfed infant, or the effects of etravirine on milk production.

Because of the potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants) and (3) adverse reactions in breastfed infants similar to those seen in adults, instruct mothers not to breastfeed if they are receiving INTELENCE.

Clinical Trials Experience in Adults

The safety assessment is based on all data from 1203 subjects in the Phase 3 placebo-controlled trials, TMC125-C206 and TMC125-C216, conducted in antiretroviral treatment-experienced HIV-1-infected adult subjects, 599 of whom received INTELENCE (200 mg twice daily). In these pooled trials, the median exposure for subjects in the INTELENCE arm and placebo arm was 52.3 and 51.0 weeks, respectively. Discontinuations due to adverse drug reactions (ADRs) were 5.2% in the INTELENCE arm and 2.6% in the placebo arm.

The most frequently reported ADR at least Grade 2 in severity was rash (10.0%). Stevens-Johnson syndrome, drug hypersensitivity reaction and erythema multiforme were reported in less than 0.1% of subjects during clinical development with INTELENCE [see Warnings and Precautions (5.1)] . A total of 2.2% of HIV-1-infected subjects in Phase 3 trials receiving INTELENCE discontinued due to rash. In general, in clinical trials, rash was mild to moderate, occurred primarily in the second week of therapy, and was infrequent after Week 4. Rash generally resolved within 1 to 2 weeks on continued therapy. The incidence of rash was higher in women compared to men in the INTELENCE arm in the Phase 3 trials (rash ≥ Grade 2 was reported in 9/60 [15.0%] women versus 51/539 [9.5%] men; discontinuations due to rash were reported in 3/60 [5.0%] women versus 10/539 [1.9%] men) [see Warnings and Precautions (5.1)] . Patients with a history of NNRTI-related rash did not appear to be at increased risk for the development of INTELENCE-related rash compared to patients without a history of NNRTI-related rash.

Clinical Trials Experience in Pediatric Subjects (2 Years to Less Than 18 years of age)

The safety assessment in pediatric subjects is based on two single-arm trials. TMC125-C213 is a Phase 2 trial in which 101 antiretroviral treatment-experienced HIV-1 infected pediatric subjects 6 years to less than 18 years of age received INTELENCE in combination with other antiretroviral agents (Week 24 analysis). TMC125-C234/IMPAACT P1090 is a Phase 1/2 trial in which 20 antiretroviral treatment-experienced HIV-1 infected pediatric subjects 2 years to less than 6 years of age received INTELENCE in combination with other antiretroviral agents (Week 24 analysis) [see Clinical Studies (14.2)] .

In TMC125-C213, the frequency, type and severity of adverse drug reactions in pediatric subjects 6 years to less than 18 years of age were comparable to those observed in adult subjects, except for rash which was observed more frequently in pediatric subjects. The most common adverse drug reactions in at least 2% of pediatric subjects were rash and diarrhea. Rash was reported more frequently in female subjects than in male subjects (rash ≥ Grade 2 was reported in 13/64 [20.3%] females versus 2/37 [5.4%] males; discontinuations due to rash were reported in 4/64 [6.3%] females versus 0/37 [0%] males). Rash (greater than or equal to Grade 2) occurred in 15% of pediatric subjects from 6 years to less than 18 years of age. In the majority of cases, rash was mild to moderate, of macular/papular type, and occurred in the second week of therapy. Rash was self-limiting and generally resolved within 1 week on continued therapy. The safety profile for subjects who completed 48 weeks of treatment was similar to the safety profile for subjects who completed 24 weeks of treatment.

In TMC125-C234/IMPAACT P1090, the frequency, type and severity of adverse drug reactions in pediatric subjects 2 years to less than 6 years of age through Week 24 were comparable to those observed in adults. The most common adverse drug reactions (any grade) of pediatric subjects were rash (50% [10/20]) and diarrhea (25% [5/20]). In this age group, no subjects had Grade 3 or Grade 4 rash and no subjects discontinued prematurely due to rash. One subject discontinued etravirine due to asymptomatic lipase elevation.

Cardiac Electrophysiology

In a thorough QT/QTc study in 41 healthy subjects, INTELENCE 200 mg twice daily or 400 mg once daily did not affect the QT/QTc interval.

Absorption and Bioavailability

Following oral administration, etravirine was absorbed with a T maxof about 2.5 to 4 hours. The absolute oral bioavailability of INTELENCE is unknown.

In healthy subjects, the absorption of etravirine is not affected by co-administration of oral ranitidine or omeprazole, drugs that increase gastric pH.

Effects of Food on Oral Absorption

The systemic exposure (AUC) to etravirine was decreased by about 50% when INTELENCE was administered under fasting conditions, as compared to when INTELENCE was administered following a meal. Within the range of meals studied, the systemic exposures to etravirine were similar. The total caloric content of the various meals evaluated ranged from 345 kilocalories (17 grams fat) to 1160 kilocalories (70 grams fat).

Distribution

Etravirine is about 99.9% bound to plasma proteins, primarily to albumin (99.6%) and alpha 1-acid glycoprotein (97.66% to 99.02%) in vitro. The distribution of etravirine into compartments other than plasma (e.g., cerebrospinal fluid, genital tract secretions) has not been evaluated in humans.

Metabolism

In vitroexperiments with human liver microsomes (HLMs) indicate that etravirine primarily undergoes metabolism by CYP3A, CYP2C9, and CYP2C19 enzymes. The major metabolites, formed by methyl hydroxylation of the dimethylbenzonitrile moiety, were at least 90% less active than etravirine against wild-type HIV in cell culture.

Elimination

After single dose oral administration of 800 mg 14C-etravirine, 93.7% and 1.2% of the administered dose of 14C-etravirine was recovered in the feces and urine, respectively. Unchanged etravirine accounted for 81.2% to 86.4% of the administered dose in feces. Unchanged etravirine was not detected in urine. The mean (± standard deviation) terminal elimination half-life of etravirine was about 41 (± 20) hours.

Specific Populations

Drug Interactions

Etravirine is a substrate of CYP3A, CYP2C9, and CYP2C19. Therefore, co-administration of INTELENCE with drugs that induce or inhibit CYP3A, CYP2C9, and CYP2C19 may alter the therapeutic effect or adverse reaction profile of INTELENCE.

Etravirine is an inducer of CYP3A and inhibitor of CYP2C9, CYP2C19 and P-gp. Therefore, co-administration of drugs that are substrates of CYP3A, CYP2C9 and CYP2C19 or are transported by P-gp with INTELENCE may alter the therapeutic effect or adverse reaction profile of the co-administered drug(s).

Drug interaction studies were performed with INTELENCE and other drugs likely to be co-administered and some drugs commonly used as probes for pharmacokinetic interactions. The effects of co-administration of other drugs on the AUC, C max, and C minvalues of etravirine are summarized in Table 8 (effect of other drugs on INTELENCE). The effect of co-administration of INTELENCE on the AUC, C max, and C minvalues of other drugs are summarized in Table 9 (effect of INTELENCE on other drugs). For information regarding clinical recommendations, [see Drug Interactions (7)] .

Mechanism of Action

Etravirine is an NNRTI of HIV-1. Etravirine binds directly to reverse transcriptase (RT) and blocks the RNA-dependent and DNA-dependent DNA polymerase activities by causing a disruption of the enzyme's catalytic site. Etravirine does not inhibit the human DNA polymerases α, β, and γ.

Antiviral Activity in Cell Culture

Etravirine exhibited activity against laboratory strains and clinical isolates of wild-type HIV-1 in acutely infected T-cell lines, human peripheral blood mononuclear cells, and human monocytes/macrophages with median EC 50values ranging from 0.9 to 5.5 nM (i.e., 0.4 to 2.4 ng/mL). Etravirine demonstrated antiviral activity in cell culture against a broad panel of HIV-1 group M isolates (subtype A, B, C, D, E, F, G) with EC 50values ranging from 0.29 to 1.65 nM and EC 50values ranging from 11.5 to 21.7 nM against group O primary isolates. Etravirine did not show antagonism when studied in combination with the following antiretroviral drugs—the NNRTIs delavirdine, efavirenz, and nevirapine; the N(t)RTIs abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir, and zidovudine; the PIs amprenavir, atazanavir, darunavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir; the gp41 fusion inhibitor ENF; the integrase strand transfer inhibitor raltegravir and the CCR5 co-receptor antagonist maraviroc.

Resistance

Cross-Resistance

Cross-resistance among NNRTIs has been observed. Cross-resistance to delavirdine, efavirenz, and/or nevirapine is expected after virologic failure with an etravirine-containing regimen. Virologic failure on a rilpivirine-containing regimen with development of rilpivirine resistance is likely to result in cross-resistance to etravirine (see Treatment-Naïve HIV-1-Infected Subjects in the Phase 3 Trials for EDURANT (rilpivirine)below). Cross-resistance to etravirine has been observed after virologic failure on a doravirine-containing regimen with development of doravirine resistance. Some NNRTI-resistant viruses are susceptible to etravirine, but genotypic and phenotypic testing should guide the use of etravirine (see Baseline Genotype/Phenotype and Virologic Outcome Analysesbelow).

Baseline Genotype/Phenotype and Virologic Outcome Analyses

In TMC125-C206 and TMC125-C216, the presence at baseline of the substitutions L100I, E138A, I167V, V179D, V179F, Y181I, Y181V, or G190S was associated with a decreased virologic response to etravirine. Additional substitutions associated with a decreased virologic response to etravirine when in the presence of 3 or more additional 2008 IAS-USA defined NNRTI substitutions include A98G, K101H, K103R, V106I, V179T, and Y181C. The presence of K103N, which was the most prevalent NNRTI substitution in TMC125-C206 and TMC125-C216 at baseline, did not affect the response in the INTELENCE arm. Overall, response rates to etravirine decreased as the number of baseline NNRTI substitutions increased (shown as the proportion of subjects achieving viral load less than 50 plasma HIV RNA copies/mL at Week 48) (Table 10).

Response rates assessed by baseline etravirine phenotype are shown in Table 11. These baseline phenotype groups are based on the select subject populations in TMC125-C206 and TMC125-C216 and are not meant to represent definitive clinical susceptibility breakpoints for INTELENCE. The data are provided to give clinicians information on the likelihood of virologic success based on pre-treatment susceptibility to etravirine in treatment-experienced patients.

The proportion of virologic responders (viral load less than 50 HIV-1 RNA copies/mL) by the phenotypic susceptibility score (PSS) of the background therapy, including ENF, is shown in Table 12.

Carcinogenesis

Etravirine was evaluated for carcinogenic potential by oral gavage administration to mice and rats for up to approximately 104 weeks. Daily doses of 50, 200 and 400 mg/kg were administered to mice and doses of 70, 200 and 600 mg/kg were administered to rats in the initial period of approximately 41 to 52 weeks. The high and middle doses were subsequently adjusted due to tolerability and reduced by 50% in mice and by 50 to 66% in rats to allow for completion of the studies. In the mouse study, statistically significant increases in the incidences of hepatocellular carcinoma and incidences of hepatocellular adenomas or carcinomas combined were observed in treated females. In the rat study, no statistically significant increases in tumor findings were observed in either sex. The relevance of these liver tumor findings in mice to humans is not known. Because of tolerability of the formulation in these rodent studies, maximum systemic drug exposures achieved at the doses tested were lower than those in humans at the clinical dose (400 mg/day), with animal vs. human AUC ratios being 0.6-fold (mice) and 0.2-to-0.7-fold (rats).

Mutagenesis

Etravirine tested negative in the in vitroAmes reverse mutation assay, in vitrochromosomal aberration assay in human lymphocyte, and in vitroclastogenicity mouse lymphoma assay, tested in the absence and presence of a metabolic activation system. Etravirine did not induce chromosomal damage in the in vivomicronucleus test in mice.

Impairment of Fertility

No effects on fertility and early embryonic development were observed when etravirine was tested in rats at maternal doses up to 500 mg/day, resulting in systemic drug exposure up to the recommended human dose (400 mg/day).

Pediatric Subjects (6 Years to Less Than 18 Years of Age [TMC125-C213])

TMC125-C213, a single-arm, Phase 2 trial evaluating the pharmacokinetics, safety, tolerability, and efficacy of INTELENCE enrolled 101 antiretroviral treatment-experienced HIV-1 infected pediatric subjects 6 years to less than 18 years of age and weighing at least 16 kg. Subjects eligible for this trial were on an antiretroviral regimen with confirmed plasma HIV-1 RNA of at least 500 copies/mL and viral susceptibility to INTELENCE at screening.

The median baseline plasma HIV-1 RNA was 3.9 log 10copies/mL, and the median baseline CD4+ cell count was 385 × 10 6cells/mm 3.

At Week 24, 52% of subjects had HIV-1 RNA less than 50 copies per mL. The proportion of subjects with HIV-1 RNA less than 400 copies/mL was 67%. The mean CD4+ cell count increase from baseline was 112 × 10 6cells/mm 3.

Pediatric Subjects (2 Years to Less Than 6 Years of Age [TMC125-C234/IMPAACT P1090])

TMC125-C234/IMPAACT P1090 is a Phase 1/2 trial evaluating the pharmacokinetics, safety, tolerability, and efficacy of INTELENCE in 20 antiretroviral treatment-experienced HIV-1 infected pediatric subjects 2 years to less than 6 years of age. The study enrolled subjects who had virologic failure on an antiretroviral treatment regimen after at least 8 weeks of treatment, or who had interrupted treatment for at least 4 weeks. Enrolled subjects had a history of virologic failure while on an antiretroviral regimen, with a confirmed HIV-1 RNA plasma viral load greater than 1,000 copies/mL and with no evidence of phenotypic resistance to etravirine at screening.

The median baseline plasma HIV-1 RNA was 4.4 log 10copies/mL, the median baseline CD4+ cell count was 817.5 × 10 6cells/mm 3, and the median baseline CD4+ percentage was 28%.

Virologic response, defined as achieving plasma viral load less than 400 HIV-1 RNA copies/mL, was evaluated.

Study treatment included etravirine plus an optimized background regimen of antiretroviral drugs. In addition to etravirine, all 20 subjects received a ritonavir-boosted protease inhibitor in combination with 1 or 2 NRTIs (n=14) and/or in combination with an integrase inhibitor (n=7).

At the time of the Week 24 analysis, seventeen subjects had completed at least 24 weeks of treatment or discontinued earlier. At Week 24, the proportion of subjects with less than 400 HIV-1 RNA copies/mL was 88% (15/17), and the proportion of subjects with less than 50 HIV-1 RNA copies/mL was 50% (7/14), for those with available data. The median change in plasma HIV-1 RNA from baseline to Week 24 was -2.14 log 10copies/mL. The median CD4+ cell count increase and the median CD4+ percentage increase from baseline was 298 × 10 6cells/mm 3and 5%, respectively.