Bedaquiline in the treatment of multidrug- and extensively drug-resistant tuberculosis.

Bedaquiline, a diarylquinoline, improved cure rates when added to a multidrug-resistant tuberculosis (MDR-TB) treatment regimen in a previous placebo-controlled, phase 2 trial (TMC207-C208; NCT00449644). The current phase 2, multicenter, open-label, single-arm trial (TMC207-C209; NCT00910871) reported here was conducted to confirm the safety and efficacy of bedaquiline.Newly diagnosed or previously treated patients with MDR-TB (including pre-extensively drug-resistant (pre-XDR)-TB or extensively drug-resistant (XDR)-TB) received bedaquiline for 24 weeks with a background regimen of anti-TB drugs continued according to National TB Programme treatment guidelines. Patients were assessed during and up to 120 weeks after starting bedaquiline.Of 233 enrolled patients, 63.5% had MDR-TB, 18.9% had pre-XDR-TB and 16.3% had XDR-TB, with 87.1% having taken second-line drugs prior to enrolment. 16 patients (6.9%) died. 20 patients (8.6%) discontinued before week 24, most commonly due to adverse events or MDR-TB-related events. Adverse events were generally those commonly associated with MDR-TB treatment. In the efficacy population (n=205), culture conversion (missing outcome classified as failure) was 72.2% at 120 weeks, and 73.1%, 70.5% and 62.2% in MDR-TB, pre-XDR-TB and XDR-TB patients, respectively.Addition of bedaquiline to a background regimen was well tolerated and led to good outcomes in this clinically relevant patient cohort with MDR-TB.

Multidrug-resistant tuberculosis and culture conversion with bedaquiline.

BACKGROUND: Bedaquiline (Sirturo, TMC207), a diarylquinoline that inhibits mycobacterial ATP synthase, has been associated with accelerated sputum-culture conversion in patients with multidrug-resistant tuberculosis, when added to a preferred background regimen for 8 weeks. METHODS: In this phase 2b trial, we randomly assigned 160 patients with newly diagnosed, smear-positive, multidrug-resistant tuberculosis to receive either 400 mg of bedaquiline once daily for 2 weeks, followed by 200 mg three times a week for 22 weeks, or placebo, both in combination with a preferred background regimen. The primary efficacy end point was the time to sputum-culture conversion in liquid broth. Patients were followed for 120 weeks from baseline. RESULTS: Bedaquiline reduced the median time to culture conversion, as compared with placebo, from 125 days to 83 days (hazard ratio in the bedaquiline group, 2.44; 95% confidence interval, 1.57 to 3.80; P<0.001 by Cox regression analysis) and increased the rate of culture conversion at 24 weeks (79% vs. 58%, P=0.008) and at 120 weeks (62% vs. 44%, P=0.04). On the basis of World Health Organization outcome definitions for multidrug-resistant tuberculosis, cure rates at 120 weeks were 58% in the bedaquiline group and 32% in the placebo group (P=0.003). The overall incidence of adverse events was similar in the two groups. There were 10 deaths in the bedaquiline group and 2 in the placebo group, with no causal pattern evident. CONCLUSIONS: The addition of bedaquiline to a preferred background regimen for 24 weeks resulted in faster culture conversion and significantly more culture conversions at 120 weeks, as compared with placebo. There were more deaths in the bedaquiline group than in the placebo group. (Funded by Janssen Pharmaceuticals; TMC207-C208 ClinicalTrials.gov number, NCT00449644.).

Population pharmacokinetics of bedaquiline (TMC207), a novel antituberculosis drug.

Bedaquiline is a novel agent for the treatment of pulmonary multidrug-resistant Mycobacterium tuberculosis infections, in combination with other agents. The objective of this study was to develop a population pharmacokinetic (PK) model for bedaquiline to describe the concentration-time data from phase I and II studies in healthy subjects and patients with drug-susceptible or multidrug-resistant tuberculosis (TB). A total of 5,222 PK observations from 480 subjects were used in a nonlinear mixed-effects modeling approach. The PK was described with a 4-compartment disposition model with dual zero-order input (to capture dual peaks observed during absorption) and long terminal half-life (t1/2). The model included between-subject variability on apparent clearance (CL/F), apparent central volume of distribution (Vc/F), the fraction of dose via the first input, and bioavailability (F). Bedaquiline was widely distributed, with apparent volume at steady state of >10,000 liters and low clearance. The long terminal t1/2 was likely due to redistribution from the tissue compartments. The final covariate model adequately described the data and had good simulation characteristics. The CL/F was found to be 52.0% higher for subjects of black race than that for subjects of other races, and Vc/F was 15.7% lower for females than that for males, although their effects on bedaquiline exposure were not considered to be clinically relevant. Small differences in F and CL/F were observed between the studies. The residual unexplained variability was 20.6% and was higher (27.7%) for long-term phase II studies.

Lack of an effect of rilpivirine on the pharmacokinetics of ethinylestradiol and norethindrone in healthy volunteers.

UNLABELLED: Rilpivirine is a human immunodeficiency virus Type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor. OBJECTIVE: Rilpivirine metabolism involves cytochrome P450 3A4 (CYP3A4). This trial (ClinicalTrials. gov number: NCT00739622) evaluated the interaction between rilpivirine and ethinylestradiol/norethindrone (combination oral contraceptives), which are metabolized by multiple pathways, including CYP3A4. METHODS: During three consecutive 28-day cycles, 18 HIV-negative females received once-daily ethinylestradiol (35 µg)/norethindrone (1 mg) (Days 1 - 21); Days 22 - 28 were pill-free. Only in Cycle 3 was once-daily rilpivirine (25 mg) co-administered (Days 1 - 15). Minimum and maximum plasma concentrations (Cmin; Cmax) and area under the plasma concentration-time curve over 24 hours (AUC24h) of ethinylestradiol/norethindrone (Day 15, Cycles 2 and 3) and rilpivirine (Day 15, Cycle 3) were evaluated. RESULTS: Rilpivirine coadministration had no effect on (least square mean ratio, 90% confidence interval) ethinylestradiol Cmin (1.09, 1.03 - 1.16) or AUC24h (1.14, 1.10 - 1.19), but increased Cmax by 17% (1.17, 1.06 - 1.30), which is unlikely to affect ethinylestradiol pharmacodynamics. Norethindrone pharmacokinetics were unaffected by rilpivirine (AUC24h: 0.89, 0.84 - 0.94; Cmin: 0.99, 0.90 - 1.08; Cmax: 0.94, 0.83 - 1.06). Steady-state rilpivirine pharmacokinetics with ethinylestradiol/norethindrone was comparable with historical data for rilpivirine alone. Rilpivirine with ethinylestradiol/norethindrone was generally well tolerated. No new safety events were identified. CONCLUSIONS: Co-administration of rilpivirine, at the therapeutic dosing regimen, with ethinylestradiol/norethindrone does not affect hormone pharmacokinetics, and is, therefore, unlikely to affect the efficacy or safety of this oral hormonal contraceptive. Rilpivirine pharmacokinetics was not affected by ethinylestradiol/norethindrone. Rilpivirine (25 mg once daily) can be co-administered with ethinylestradiol/norethindrone-based contraceptives without dose modification.

The effect of rilpivirine on the pharmacokinetics of methadone in HIV-negative volunteers.

Antiretrovirals may influence methadone exposure in HIV-1-infected patients receiving methadone for opiate addiction. Rilpivirine is a non-nucleoside reverse transcriptase inhibitor for treating HIV-1 infection. In this open-label trial (NCT00744770), 13 HIV-negative volunteers continued on their regular stable methadone therapy (60 to 100 mg once daily; Days -14 to 12), with rilpivirine coadministration (Days 1 to 11). Methadone and rilpivirine pharmacokinetics and opiate withdrawal symptoms (Short Opiate Withdrawal Scale, Desires for Drugs Questionnaire, pupillometry) were evaluated. Rilpivirine decreased methadone minimum and maximum plasma concentrations (Cmin ; Cmax ) and area under the plasma concentration-time curve versus methadone alone (least-square mean ratio; 90% confidence interval) by 22% (0.78; 0.67, 0.91), 14% (0.86; 0.78, 0.95), and 16% (0.84; 0.74, 0.95), respectively (R-methadone), and 21% (0.79; 0.67, 0.92), 13% (0.87; 0.78, 0.97), and 16% (0.84; 0.74, 0.96), respectively (S-methadone). Rilpivirine pharmacokinetics with methadone were consistent with historic data. No clinically relevant opiate withdrawal symptoms were reported. Methadone and rilpivirine coadministration was generally well tolerated. No grade 3/4 adverse events (AEs), serious AEs, or discontinuations due to AEs were seen. No methadone dose adjustment is prompted by rilpivirine coadministration. Clinical monitoring for opiate withdrawal is recommended, as some patients may require adjustment of methadone maintenance therapy.

Impact of food and different meal types on the pharmacokinetics of rilpivirine.

The objective of the study was to determine the impact of food and different meal types on the pharmacokinetics of rilpivirine, a nonnucleoside reverse transcriptase inhibitor. In this open-label, randomized, crossover study, healthy volunteers received a single, oral 75 mg dose of rilpivirine either with a normal-fat breakfast (reference), under fasting conditions, with a high-fat breakfast, or with a protein-rich nutritional drink. Pharmacokinetic parameters were determined by non-compartmental methods and analyzed using a linear mixed-effects model. Safety was assessed throughout. The least-squares mean ratio for area under the plasma concentration-time curve to last timepoint was 0.57 (90% confidence interval [CI]: 0.46-0.72) under fasting conditions compared to dosing with a normal-fat breakfast. With a high-fat breakfast or only a protein-rich nutritional drink, the corresponding values were 0.92 (90% CI: 0.80-1.07) and 0.50 (90% CI: 0.41-0.61), respectively, compared to dosing with a normal-fat breakfast. Under all conditions, rilpivirine was generally safe and well tolerated. Administration of rilpivirine under fasting conditions or with only a protein-rich nutritional drink substantially lowered the oral bioavailability when compared to administration with a normal-fat breakfast. Rilpivirine bioavailability was similar when administered with a high-fat or normal-fat breakfast. Rilpivirine should always be taken with a meal to ensure adequate bioavailability.

Clinical perspective on drug-drug interactions with the non-nucleoside reverse transcriptase inhibitor rilpivirine.

Rilpivirine (TMC278) is a non-nucleoside reverse transcriptase inhibitor approved in combination with other antiretrovirals for the treatment of HIV-1 infection in treatment-naive adults (Edurant(®) 25 mg once daily; Complera(®) [USA]/Eviplera(®) [EU] once daily single-tablet regimen). Rilpivirine should be administered with a meal to optimize bioavailability. Its solubility is pH dependent. Rilpivirine is primarily excreted via the feces with negligible renal elimination. Rilpivirine is predominantly metabolized by cytochrome P450 3A4. There is no clinically relevant effect of age, gender, bodyweight, race, estimated glomerular filtration rate, or hepatitis B/C coinfection status on rilpivirine pharmacokinetics in adults. Drug-drug interactions were investigated with cytochrome P450 3A substrates, inducers and inhibitors, drugs altering intragastric pH, antiretrovirals, and other often coadministered drugs. Rilpivirine 25 mg once daily does not have a clinically relevant effect on exposure of coadministered drugs. Coadministration with cytochrome P450 3A inhibitors (ketoconazole, ritonavir-boosted protease inhibitors, telaprevir) results in increased rilpivirine plasma concentrations, but these are not considered clinically relevant; no dose adjustments are required. Coadministration of rilpivirine with cytochrome P450 3A inducers (e.g. rifampin, rifabutin) or compounds increasing gastric pH (e.g. omeprazole, famotidine) results in decreased rilpivirine plasma concentrations, which may increase the risk of virologic failure and resistance development. Therefore, strong cytochrome P450 3A inducers and proton-pump inhibitors are contraindicated. Histamine-2 receptor antagonists and antacids can be coadministered with rilpivirine, provided doses are temporally separated. No dose adjustments are required when rilpivirine is coadministered with: acetaminophen, phosphodiesterase type 5 inhibitors (sildenafil, etc.), atorvastatin (and other statins), oral contraceptives (ethinyl estradiol, norethindrone), chlorzoxazone (cytochrome P450 2E1 substrate), methadone, digoxin, tenofovir disoproxil fumarate, didanosine and other nuceos(t)ide reverse transcriptase inhibitors, and HIV integrase inhibitors (raltegravir, dolutegravir, GSK1265744).

Pharmacokinetic interaction between telaprevir and methadone.

Hepatitis C virus (HCV) antibody is present in most patients enrolled in methadone maintenance programs. Therefore, interactions between the HCV protease inhibitor telaprevir and methadone were investigated. The pharmacokinetics of R- and S-methadone were measured after administration of methadone alone and after 7 days of telaprevir (750 mg every 8 h [q8h]) coadministration in HCV-negative subjects on stable, individualized methadone therapy. Unbound R-methadone was measured in predose plasma samples before and during telaprevir coadministration. Safety and symptoms of opioid withdrawal were evaluated throughout the study. In total, 18 subjects were enrolled; 2 discontinued prior to receiving telaprevir. The minimum plasma concentration in the dosing interval (C(min)), the maximum plasma concentration (Cmax), and the area under the plasma concentration-time curve from h 0 (time of administration) to 24 h postdose (AUC(0-24)) for R-methadone were reduced by 31%, 29%, and 29%, respectively, in the presence of telaprevir. The AUC0-24 ratio of S-methadone/R-methadone was not altered. The median unbound percentage of R-methadone increased by 26% in the presence of telaprevir. The R-methadone median (absolute) unbound C(min) values in the absence (10.63 ng/ml) and presence (10.45 ng/ml) of telaprevir were similar. There were no symptoms of opioid withdrawal and no discontinuations due to adverse events. In summary, exposure to total R-methadone was reduced by approximately 30% in the presence of telaprevir, while the exposure to unbound R-methadone was unchanged. No symptoms of opioid withdrawal were observed. These results suggest that dose adjustment of methadone is not required when initiating telaprevir treatment. (This study has been registered at ClinicalTrials.gov under registration no. NCT00933283.).

Review of drug interactions with telaprevir and antiretrovirals.

HCV infection is a major cause of mortality worldwide. HCV-related deaths also represent a leading cause of mortality in HIV-coinfected individuals. Telaprevir is an NS3/4A protease inhibitor approved for the treatment of chronic HCV genotype 1 infection in adults in combination with pegylated interferon and ribavirin. Telaprevir-based treatment has been shown to increase rates of sustained viral response in HCV genotype-1-monoinfected patients, and studies in HCV-HIV-coinfected patients are ongoing. Drug-drug interactions of telaprevir with antiretroviral drugs were investigated in a series of studies in healthy subjects. This review summarizes the results of interaction studies with low-dose ritonavir, ritonavir-boosted HIV protease inhibitors (atazanavir, darunavir, fosamprenavir and lopinavir), efavirenz, etravirine, rilpivirine, tenofovir disoproxil fumarate and raltegravir.

Limited impact of IL28B genotype on response rates in telaprevir-treated patients with prior treatment failure.

BACKGROUND & AIMS: Nucleotide polymorphisms upstream of the interleukin 28B (IL28B) gene are strongly associated with hepatitis C virus (HCV) clearance in treatment-naïve patients treated with peginterferon/ribavirin (PegIFN/RBV). This subanalysis of the REALIZE study evaluated the impact of IL28B polymorphisms on sustained virologic response (SVR) in telaprevir-treated, HCV genotype 1-infected patients with prior PegIFN/RBV treatment failure. METHODS: Treatment-experienced patients were randomized to 12 weeks of telaprevir (750 mg every 8h) with/without a 4-week PegIFN/RBV lead-in, or placebo, each with PegIFN-α-2a (180 µg/week) and ribavirin (1000-1200 mg/day) for 48 weeks overall. Data from telaprevir arms were pooled. RESULTS: Eighty percent (527/662) of patients consented to genetic testing and were included. Similar proportions of patients had IL28B CC, CT and TT genotypes across treatment arms; baseline characteristics were generally well balanced. SVR rates were higher in the pooled telaprevir versus placebo group for all IL28B genotypes; CC: 79% versus 29%, respectively; CT: 60% versus 16%, respectively; TT: 61% versus 13%, respectively. Within each prior response category (relapse, partial or null response), SVR and viral breakthrough rates with telaprevir-based treatment were comparable across IL28B genotypes. IL28B genotype did not significantly affect SVR (2-step multivariate analyses; p >0.16 in pairwise comparison among CC, TT, and CT). Variations in rapid virologic response and relapse rates were noted in certain patient subgroups. CONCLUSIONS: Our findings suggest that IL28B genotype has a limited impact on SVR rates with telaprevir-based therapy in treatment-experienced patients. IL28B genotyping may have limited utility in the baseline evaluation of similar patients considered for telaprevir-based therapy.

The effect of CYP3A inhibitors and inducers on the pharmacokinetics of telaprevir in healthy volunteers.

AIM: To evaluate the effects of ketoconazole, rifampicin and efavirenz on the pharmacokinetics of telaprevir in healthy volunteers. METHOD: Results from three clinical studies are described. (1) Volunteers received a single 750 mg dose telaprevir with and without a single 400 mg dose ketoconazole. (2) Volunteers received (a) 1250 mg telaprevir followed by three 750 mg doses given every 8 h and (b) four 1250 mg telaprevir doses given every 8 h, with a single 400 mg dose ketoconazole given with the fourth dose of telaprevir. (3) Volunteers received either a single 750 mg dose telaprevir with or without 600 mg once daily rifampicin, or 750 mg every 8 h telaprevir with and without 600 mg once daily efavirenz. RESULTS: A single 400 mg dose of ketoconazole increased single dose telaprevir exposure: the geometric least-squares mean ratio (GLSMR, with 90% confidence limits) was 1.24 (1.10, 1.41) for C(max) and 1.62 (1.45, 1.81) for AUC(0,∞). However, after multiple doses of telaprevir, there was no discernible effect of ketoconazole on telaprevir exposure. Co-administration of rifampicin at steady-state markedly reduced single dose telaprevir exposure with GLSMRs of 0.14 (0.11, 0.18) for C(max) and 0.08 (0.07, 0.11) for AUC(0,∞), whereas efavirenz had a smaller effect on telaprevir exposure when both drugs were co-administered at steady-state, with GLSMRs of 0.91 (0.81, 1.02) for C(max) , 0.53 (0.44, 0.65) for C(min), and 0.74 (0.65, 0.84) for AUC(0,8 h). CONCLUSION: CYP3A inducers, rifampicin and efavirenz, can reduce telaprevir exposure to varying degrees based on their potency. The effect of ketoconazole as an inhibitor of telaprevir metabolism is more pronounced after a single dose of telaprevir than after repeated administration.

Telaprevir: pharmacokinetics and drug interactions.

Telaprevir is an inhibitor of the HCV NS3/4A protease. When used in combination with pegylated interferon and ribavirin, telaprevir has demonstrated a substantial increase in sustained virological response compared with pegylated interferon and ribavirin used alone. Telaprevir has good oral bioavailability, which is enhanced when administered with food. Telaprevir is extensively metabolized and primarily eliminated via faeces. No dose adjustment of telaprevir is needed in patients with mild to severe renal impairment or mild liver impairment. Telaprevir is a substrate and inhibitor of cytochrome P450 3A and P-glycoprotein and, thus, might interact with coadministered drugs that affect or are affected by these metabolic/transport pathways. This article reviews the pharmacokinetic and drug interaction profile of telaprevir.

Effect of telaprevir on the pharmacokinetics of buprenorphine in volunteers on stable buprenorphine/naloxone maintenance therapy.

This was an open-label, single-sequence trial in hepatitis C virus-negative volunteers on stable, individualized, buprenorphine maintenance therapy. Telaprevir at 750 mg every 8 h was coadministered with buprenorphine/naloxone (4:1 ratio as sublingual tablets) for 7 days with food. Pharmacokinetic profiles of buprenorphine, norbuprenorphine, and naloxone were measured over the 24-hour dosing interval on day -1 (buprenorphine/naloxone alone, reference) and day 7 of telaprevir coadministration (test). Geometric least-squares mean ratios and associated 90% confidence intervals of treatment ratios (test/reference) were calculated using log-transformed pharmacokinetic parameters. Opioid withdrawal symptoms were evaluated throughout the study (via questionnaires and pupillometry). Pharmacokinetic data were available for 14 and 13 volunteers on day -1 and day 7, respectively. The area under the concentration-time curve (AUC) for buprenorphine was unchanged and the maximum concentration of drug in serum (C(max)) for buprenorphine, C(max) and AUC for norbuprenorphine, and C(max) naxolone were modestly decreased during coadministration with telaprevir. Geometric least-squares mean ratios (90% confidence intervals) for buprenorphine were 0.80 (0.69, 0.93) for the C(max) and 0.96 (0.84, 1.10) for the AUC from 0 to 24 h (AUC(0-24)); for norbuprenorphine, values were 0.85 (0.66, 1.09) for C(max) and 0.91 (0.71, 1.16) for AUC(0-24); for naloxone, the C(max) was 0.84 (0.62, 1.13). Coadministration of telaprevir did not increase withdrawal symptom frequency, and there were no serious adverse events reported during or after completion of telaprevir coadministration. Results suggest dose adjustment may not be necessary when telaprevir and buprenorphine/naloxone are coadministered.

The effect of ß-carotene supplementation on the pharmacokinetics of nelfinavir and its active metabolite M8 in HIV-1-infected patients.

ß-Carotene supplements are often taken by individuals living with HIV-1. Contradictory results from in vitro studies suggest that ß-carotene may inhibit or induce cytochrome P450 enzymes and transporters. The study objective was to investigate the effect of ß-carotene on the steady-state pharmacokinetics of nelfinavir and its active metabolite M8 in HIV-1 infected individuals. Twelve hour nelfinavir pharmacokinetic analysis was conducted at baseline and after 28 days of ß-carotene supplementation (25,000 IU twice daily). Nelfinavir and M8 concentrations were measured with validated assays. Non-compartmental methods were used to calculate the pharmacokinetic parameters. Geometric mean ratios comparing day 28 to day 1 area under the plasma concentration-time curve (AUC(0-12 h)), maximum (C(max)) and minimum (C(min)) concentrations of nelfinavir and M8 are presented with 90% confidence intervals. Eleven subjects completed the study and were included in the analysis. There were no significant differences in nelfinavir AUC(0-12 h) and C(min) (-10%, +4%) after ß-carotene supplementation. The M8 C(min) was increased by 31% while the M8 AUC(0-12 h) and C(max) were unchanged. During the 28 day period, mean CD4+ % and CD4+:CD8+ ratio increased significantly (p < 0.01). ß-carotene supplementation increased serum carotene levels but did not cause any clinically significant difference in the nelfinavir and M8 exposure.

The pharmacokinetic interaction between an oral contraceptive containing ethinyl estradiol and norethindrone and the HCV protease inhibitor telaprevir.

BACKGROUND: Telaprevir is a hepatitis C virus protease inhibitor that is both a substrate and an inhibitor of CYP3A. STUDY DESIGN: The effect of steady-state telaprevir (administered 750 mg every 8 hours) on the steady-state pharmacokinetics of ethinyl estradiol (EE) and norethindrone (NE) was evaluated in 24 healthy women receiving oral contraceptives (OC) containing 0.5 mg NE and 0.035 mg EE for at least 3 months at the time of screening. This was a phase 1, open-label, single-center, nonrandomized study that included a cycle 1 (OC only for 21 days, followed by no OC for 7 days), cycle 2 (OC plus telaprevir for 21 days, followed by telaprevir alone for 7 days), and a follow-up period. RESULTS: When administration with or without telaprevir was compared, the least-squares mean ratios (90% confidence limits) for EE were 0.74 (0.68; 0.80) for C(max), 0.67 (0.63; 0.71) for C(min), and 0.72 (0.69; 0.75) for AUC; neither NE nor telaprevir exposure was affected. CONCLUSIONS: The efficacy of the OC may be compromised by the 26% to 33% reduction in EE exposure. Therefore, alternative methods of nonhormonal contraception should be used when hormonal contraceptives are coadministered with telaprevir and for up to 2 weeks following cessation of telaprevir.

Effect of telaprevir on the pharmacokinetics of midazolam and digoxin.

In this open-label study, 24 healthy volunteers received a single intravenous (IV) dose of 0.5 mg of midazolam on day 1 and a single oral dose each of 2 mg of midazolam and 0.5 mg of digoxin on day 3. Telaprevir 750 mg every 8 hours was administered from day 8 through day 23, along with a single IV dose of 0.5 mg of midazolam on day 17 and single oral doses of 2 mg of midazolam and 0.5 mg of digoxin on day 19. Midazolam, 1'-hydroxymidazolam, digoxin, and telaprevir concentrations in plasma and digoxin concentrations in urine were measured and pharmacokinetic parameters calculated. On comparing administration with versus without telaprevir, the geometric least squares mean ratios (with 90% confidence limits) for IV midazolam were 1.02 (0.80, 1.31) for maximum observed concentrations (C(max)) and 3.40 (3.04, 3.79) for area under the curve from 0 to 24 hours (AUC(0-24h)); for oral midazolam 2.86 (2.52, 3.25) for C(max) and 8.96 (7.75, 10.35) for AUC(0-24h); and for oral digoxin 1.50 (1.36, 1.65) for C(max) and 1.85 (1.70, 2.00) for area under the curve from 0 to infinity (AUC(0-∞)). Coadministration of telaprevir with oral midazolam resulted in approximately 3-fold decrease in the mean AUC(0-∞) of 1'-hydroxymidazolam. The renal clearance of digoxin was similar with or without telaprevir. Results show that telaprevir is an inhibitor of CYP3A and P-glycoprotein.

Safety, tolerability, and pharmacokinetic interactions of the antituberculous agent TMC207 (bedaquiline) with efavirenz in healthy volunteers: AIDS Clinical Trials Group Study A5267.

BACKGROUND: Drug-drug interactions complicate management of coinfection with HIV-1 and Mycobacterium tuberculosis. Bedaquiline (formerly TMC207), an investigational agent for the treatment of tuberculosis, is metabolized by cytochrome P450 (CYP) 3A which may be induced by the antiretroviral drug efavirenz. METHODS: This was a phase 1 pharmacokinetic drug interaction trial. Each healthy volunteer received two 400 mg doses of bedaquiline, the first alone and the second with concomitant steady-state efavirenz. Plasma pharmacokinetic sampling for bedaquiline and its N-monodesmethyl metabolite was performed over 14 days after each bedaquiline dose. Steady-state efavirenz pharmacokinetics were also determined. Efavirenz metabolizer status was based on CYP2B6 composite 516/983 genotype. RESULTS: Thirty-three of 37 enrolled subjects completed the study. Geometric mean of ratios for bedaquiline with efavirenz versus bedaquiline alone were 0.82 [90% confidence interval (CI): 0.75 to 0.89] for the 14-day area under the concentration-time curve (AUC0-336 h) and 1.00 (90% CI: 0.88 to 1.13) for the maximum concentration (Cmax). For N-monodesmethyl metabolite, the geometric mean of ratios was 1.07 (90% CI: 0.97 to 1.19) for AUC0-336 h and 1.89 (90% CI: 1.66 to 2.15) for C(max). There were no grade 3 or 4 clinical adverse events. One subject developed asymptomatic grade 3 serum transaminase elevation, prompting study drug discontinuation. Efavirenz concentrations stratified by CYP2B6 genotype were similar to historical data. CONCLUSIONS: Single-dose bedaquiline was well tolerated alone and with steady-state efavirenz. The effect of efavirenz on bedaquiline concentrations is unlikely to be clinically significant.

Effect of the hepatitis C virus protease inhibitor telaprevir on the pharmacokinetics of amlodipine and atorvastatin.

Telaprevir is a hepatitis C virus protease inhibitor that is both a substrate and an inhibitor of CYP3A. Amlodipine and atorvastatin are both substrates of CYP3A and are among the drugs most frequently used by patients with hepatitis C. This study was conducted to examine the effect of telaprevir on atorvastatin and amlodipine pharmacokinetics (PK). This was an open-label, single sequence, nonrandomized study involving 21 healthy male and female volunteers. A coformulation of 5 mg amlodipine and 20 mg atorvastatin was administered on day 1. Telaprevir was taken with food as a 750-mg dose every 8 h from day 11 until day 26, and a single dose of the amlodipine-atorvastatin combination was readministered on day 17. Plasma samples were collected for determination of the PK of telaprevir, amlodipine, atorvastatin, ortho-hydroxy atorvastatin, and para-hydroxy atorvastatin. When administration with telaprevir was compared with administration without telaprevir, the least-square mean ratios (90% confidence limits) for amlodipine were 1.27 (1.21, 1.33) for the maximum drug concentration in serum (C(max)) and 2.79 (2.58, 3.01) for the area under the concentration-time curve from 0 h to infinity (AUC(0-∞)); for atorvastatin, they were 10.6 (8.74, 12.9) for the C(max) and 7.88 (6.84, 9.07) for the AUC(0-∞). Telaprevir significantly increased exposure to amlodipine and atorvastatin, consistent with the inhibitory effect of telaprevir on the CYP3A-mediated metabolism of these agents.

Telaprevir alone or with peginterferon and ribavirin reduces HCV RNA in patients with chronic genotype 2 but not genotype 3 infections.

BACKGROUND & AIMS: We evaluated antiviral activity of 2 weeks therapy with telaprevir alone, peginterferon alfa-2a and ribavirin (PR), or all 3 drugs (TPR) in treatment-naïve patients with chronic hepatitis C virus (HCV) genotype 2 or 3 infections. METHODS: We performed a randomized, multicenter, partially blinded study of patients (23 with HCV genotype 2, 26 with genotype 3) who received telaprevir (750 mg every 8 h), placebo plus PR (peginterferon, 180 µg, once weekly and ribavirin, 400 mg, twice daily), or TPR for 15 days, followed by PR for 22 or 24 weeks. Plasma levels of HCV RNA were quantified. RESULTS: Levels of HCV RNA decreased in all patients with HCV genotype 2, including those who received telaprevir monotherapy. The decrease was more rapid among patients who received telaprevir. By day 15, 0% (telaprevir), 40% (TPR), and 22% (PR) of patients with HCV genotype 2 had undetectable levels of HCV RNA; rates of sustained virologic response were 56%, 100%, and 89%, respectively. Overall, 6 of 9 HCV genotype 2 patients that received only telaprevir had viral breakthrough within 15 days after an initial response. HCV RNA levels decreased slightly among patients with HCV genotype 3 who received telaprevir and decreased rapidly among patients given PR or TPR (telaprevir had no synergistic effects with PR). Sustained virologic response rates were 50%, 67%, and 44% among patients given telaprevir, TPR, or PR respectively; 7 patients with HCV genotype 3 relapsed after therapy (2 given telaprevir, 3 given TPR, and 2 given PR) and 3 patients with HCV genotype 3 had viral breakthrough during telaprevir monotherapy. The incidence of adverse events was similar among groups. CONCLUSIONS: Telaprevir monotherapy for 2 weeks reduces levels of HCV RNA in patients with chronic HCV genotype 2 infections, but has limited activity in patients with HCV genotype 3.

Telaprevir for retreatment of HCV infection.

BACKGROUND: Up to 60% of patients with hepatitis C virus (HCV) genotype 1 infection do not have a sustained virologic response to therapy with peginterferon alfa plus ribavirin. METHODS: In this randomized, phase 3 trial, we evaluated the addition of telaprevir to peginterferon alfa-2a plus ribavirin in patients with HCV genotype 1 infection who had no response or a partial response to previous therapy or who had a relapse after an initial response. A total of 663 patients were assigned to one of three groups: the T12PR48 group, which received telaprevir for 12 weeks and peginterferon plus ribavirin for a total of 48 weeks; the lead-in T12PR48 group, which received 4 weeks of peginterferon plus ribavirin followed by 12 weeks of telaprevir and peginterferon plus ribavirin for a total of 48 weeks; and the control group (PR48), which received peginterferon plus ribavirin for 48 weeks. The primary end point was the rate of sustained virologic response, which was defined as undetectable HCV RNA 24 weeks after the last planned dose of a study drug. RESULTS: Rates of sustained virologic response were significantly higher in the two telaprevir groups than in the control group among patients who had a previous relapse (83% in the T12PR48 group, 88% in the lead-in T12PR48 group, and 24% in the PR48 group), a partial response (59%, 54%, and 15%, respectively), and no response (29%, 33%, and 5%, respectively) (P<0.001 for all comparisons). Grade 3 adverse events (mainly anemia, neutropenia, and leukopenia) were more frequent in the telaprevir groups than in the control group (37% vs. 22%). CONCLUSIONS: Telaprevir combined with peginterferon plus ribavirin significantly improved rates of sustained virologic response in patients with previously treated HCV infection, regardless of whether there was a lead-in phase. (Funded by Tibotec and Vertex Pharmaceuticals; REALIZE ClinicalTrials.gov number, NCT00703118.).