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.).

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.

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.

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.).

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.

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.

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.).

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.

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 diarylquinoline TMC207 for multidrug-resistant tuberculosis.

BACKGROUND: The diarylquinoline TMC207 offers a new mechanism of antituberculosis action by inhibiting mycobacterial ATP synthase. TMC207 potently inhibits drug-sensitive and drug-resistant Mycobacterium tuberculosis in vitro and shows bactericidal activity in patients who have drug-susceptible pulmonary tuberculosis. METHODS: In the first stage of a two-stage, phase 2, randomized, controlled trial, we randomly assigned 47 patients who had newly diagnosed multidrug-resistant pulmonary tuberculosis to receive either TMC207 (400 mg daily for 2 weeks, followed by 200 mg three times a week for 6 weeks) (23 patients) or placebo (24 patients) in combination with a standard five-drug, second-line antituberculosis regimen. The primary efficacy end point was the conversion of sputum cultures, in liquid broth, from positive to negative. RESULTS: The addition of TMC207 to standard therapy for multidrug-resistant tuberculosis reduced the time to conversion to a negative sputum culture, as compared with placebo (hazard ratio, 11.8; 95% confidence interval, 2.3 to 61.3; P=0.003 by Cox regression analysis) and increased the proportion of patients with conversion of sputum culture (48% vs. 9%). The mean log(10) count of colony-forming units in the sputum declined more rapidly in the TMC207 group than in the placebo group. No significant differences in average plasma TMC207 concentrations were noted between patients with and those without culture conversion. Most adverse events were mild to moderate, and only nausea occurred significantly more frequently among patients in the TMC207 group than among patients in the placebo group (26% vs. 4%, P=0.04). CONCLUSIONS: The clinical activity of TMC207 validates ATP synthase as a viable target for the treatment of tuberculosis. (ClinicalTrials.gov number, NCT00449644.)

Telaprevir is effective given every 8 or 12 hours with ribavirin and peginterferon alfa-2a or -2b to patients with chronic hepatitis C.

BACKGROUND & AIMS: Recent studies have shown that 12 weeks of treatment with telaprevir, administered every 8 hours (q8h), combined with pegylated interferon (peginterferon) alfa-2a plus ribavirin significantly increased the rate of hepatitis C virus (HCV) eradication (sustained virologic response [SVR]) in patients infected with HCV genotype 1 compared with approved therapy. We investigated the efficacy, safety, tolerability, and pharmacokinetics of telaprevir given q8h or every 12 hours (q12 h) in combination with peginterferon alfa-2a or alfa-2b. METHODS: Treatment-naive patients (n = 161) infected with HCV genotype 1 were randomly assigned to groups that were given open-label telaprevir (750 mg q8 h or 1125 mg q12 h) in combination with standard doses of peginterferon alfa-2a (180 µg/wk) and ribavirin (1000-1200 mg/day) or peginterferon alfa-2b (1.5 µg·kg(-1)·wk(-1)) and ribavirin (800-1200 mg/day). Patients received triple therapy for 12 weeks, followed by 12 or 36 additional weeks of treatment with peginterferon alfa and ribavirin, based on virologic response. RESULTS: Baseline characteristics were similar for all groups. SVR rates were 81.0% to 85.0% among groups; most patients received 24 weeks of therapy (68.0%). There were no significant differences in SVR rates (intent-to-treat analysis) among groups (P ≥ .787), between the pooled q8 h and q12 h groups (P = .997), or between the pooled peginterferon alfa-2a/ribavirin and peginterferon alfa-2b/ribavirin groups (P = .906). The safety profile was similar among all groups. CONCLUSIONS: A high proportion (>80%) of patients achieved an SVR regardless of the telaprevir dosing frequency (q8 h or q12 h) or type of peginterferon alfa used (alfa-2a or alfa-2b).

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.

Effect of telaprevir on the pharmacokinetics of cyclosporine and tacrolimus.

UNLABELLED: The hepatitis C virus protease inhibitor telaprevir is an inhibitor of the enzyme cytochrome P450 3A, responsible for the metabolism of both cyclosporine and tacrolimus. This Phase I, open-label, nonrandomized, single-sequence study assessed the effect of telaprevir coadministration on the pharmacokinetics of a single dose of either cyclosporine or tacrolimus in two separate panels of 10 healthy volunteers each. In Part A, cyclosporine was administered alone as a single 100-mg oral dose, followed by a minimum 8-day washout period, and subsequent coadministration of a single 10-mg oral dose of cyclosporine with either a single dose of telaprevir (750 mg) or with steady-state telaprevir (750 mg every 8 hours [q8h]). In Part B, tacrolimus was administered alone as a single 2-mg oral dose, followed by a minimum 14-day washout period, and subsequent coadministration of a single 0.5-mg dose of tacrolimus with steady-state telaprevir (750 mg q8h). Coadministration with steady-state telaprevir increased cyclosporine dose-normalized (DN) exposure (DN_AUC(0-∞)) by approximately 4.6-fold and increased tacrolimus DN_AUC(0-∞) by approximately 70-fold. Coadministration with telaprevir increased the terminal elimination half-life (t(½)) of cyclosporine from a mean (standard deviation [SD]) of 12 (1.67) hours to 42.1 (11.3) hours and t(½) of tacrolimus from a mean (SD) of 40.7 (5.85) hours to 196 (159) hours. CONCLUSION: In this study, telaprevir increased the blood concentrations of both cyclosporine and tacrolimus significantly, which could lead to serious or life-threatening adverse events. Telaprevir has not been studied in organ transplant patients; its use in these patients is not recommended because the required studies have not been completed to understand appropriate dose adjustments needed for safe coadministration of telaprevir with cyclosporine or tacrolimus, and regulatory approval has not been obtained.

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.

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.

Pharmacokinetics and tolerability of once- versus twice-daily lopinavir/ritonavir treatment in HIV-1-infected children.

BACKGROUND: Once-daily lopinavir/ritonavir (LPV/r) is not approved for treatment of HIV paediatric patients. Once daily treatment in children might serve the same goals of patient comfort and adherence as in adults. METHODS: HIV type-1-infected children aged 6 months to 18 years, who were virologically suppressed on an LPV/r-containing regimen, were eligible. Treatment 1 consisted of once-daily LPV/r 460/115 mg/m(2), plus two nucleoside reverse transcriptase inhibitors (NRTIs). Treatment 2 consisted of twice-daily LPV/r 230/57.5 mg/m(2) plus two NRTIs. Patients were randomized either to start with treatment 1 followed by treatment 2 or vice versa. Full pharmacokinetic profiles were analysed for lopinavir and ritonavir with a validated HPLC tandem mass spectrometry assay. RESULTS: Seven patients (five girls and two boys) were included in the study. Median age was 9.8 years (range 5.8-15.5). For the once-daily treatment, the median (range) lopinavir 24 h area under the plasma -concentration-time curve (AUC(24 h)), maximum plasma concentration (C(max)) and 24 h plasma concentration (C(24 h)) were 214.6 h*mg/l (114.2-289.2), 13.5 mg/l (8.3-17.5) and 3.4 mg/l (0.6-7.4), respectively. For the twice-daily treatment the median (range) lopinavir 12 h area under the plasma concentration-time curve (AUC(12 h)), C(max) and 12 h plasma concentration (C(12 h)) were 80.9 h*mg/l (23.3-135.9), 9.8 mg/l (3.4-15.2) and 5.7 mg/l (1.7-9.7), respectively. CONCLUSIONS: This study suggests that the pharmacokinetics of lopinavir after twice-daily and once-daily dosing are similar, with no observable difference in tolerability, in this group of patients between 5 and 15 years old.

Short-term randomized proof-of-principle trial of TMC278 in patients with HIV type-1 who have previously failed antiretroviral therapy.

BACKGROUND: In vitro, TMC278, an investigational next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI), has shown activity against wild-type and NNRTI-resistant HIV type-1 (HIV-1) and a higher genetic barrier to the development of resistance than efavirenz or nevirapine. This Phase II open-label trial evaluated the short-term (7-day) antiviral activity of TMC278 administered at three different doses replacing either the protease inhibitor (PI) or NNRTI of an ongoing failing treatment regimen in HIV-1-infected patients. METHODS: A total of 36 patients on failing antiretroviral therapy containing either an NNRTI or a PI (with evidence of > or =1 NNRTI resistance-associated mutation at screening for the PI group) and plasma viral load (VL)>1,000 copies/ml were randomized to one of three once-daily TMC278 doses (25 mg, 50 mg or 150 mg) for 7 days, while continuing NRTIs used at screening. The primary efficacy parameter was the change on day 8 in log(10) plasma VL from baseline. RESULTS: On day 8, median (min, max) changes from baseline in plasma VL were -0.87 (-2.3, 0.0), -0.95 (-1.8, 0.4) and -0.66 (-1.3, -0.2) log(10) copies/ml for the 25 mg, 50 mg and 150 mg once-daily TMC278 groups, respectively (P<0.001-<0.01). Overall, the median change from baseline was -1.19 log(10) copies/ml in the PI-substituted therapy group and -0.71 log(10) copies/ml in the NNRTI-substituted therapy group. TMC278 was generally safe and well tolerated with no apparent differences in safety among the three dose groups. CONCLUSIONS: Once-daily TMC278 showed significant antiviral activity against HIV-1 in treatment-experienced patients with NNRTI failure and/or resistance, and was generally safe and well tolerated.

Inhibition of adenine nucleotide translocator pore function and protection against apoptosis in vivo by an HIV protease inhibitor.

Inhibitors of HIV protease have been shown to have antiapoptotic effects in vitro, yet whether these effects are seen in vivo remains controversial. In this study, we have evaluated the impact of the HIV protease inhibitor (PI) nelfinavir, boosted with ritonavir, in models of nonviral disease associated with excessive apoptosis. In mice with Fas-induced fatal hepatitis, Staphylococcal enterotoxin B-induced shock, and middle cerebral artery occlusion-induced stroke, we demonstrate that PIs significantly reduce apoptosis and improve histology, function, and/or behavioral recovery in each of these models. Further, we demonstrate that both in vitro and in vivo, PIs block apoptosis through the preservation of mitochondrial integrity and that in vitro PIs act to prevent pore function of the adenine nucleotide translocator (ANT) subunit of the mitochondrial permeability transition pore complex.

Prevention of drug carryover effects in studies assessing antimycobacterial efficacy of TMC207.

The levels of TMC207 (R207910) that can be reached in mouse organs and the sputa of treated patients easily exceed the MIC of the compound and can therefore interfere with in vitro bacterial titrations. We studied the usefulness of protein-enriched media for the prevention of such drug carryover effects. The average MIC of Mycobacterium tuberculosis was determined on three different media: unsupplemented 7H11 agar (MIC = 0.03 microg/ml), 7H11 agar supplemented with 5% bovine serum albumin (BSA; MIC = 1 microg/ml), and Lowenstein-Jensen medium (MIC = 14.33 microg/ml). In a second stage of the study, the maximal noninhibitory concentrations (MNICs) of TMC207 were determined by adding TMC207 to the bacterial inoculum rather than to the culture medium. These MNICs were 0.97 microg/ml for 7H11 agar, 32.33 microg/ml for 7H11 agar with 5% BSA, and 96.33 microg/ml for Lowenstein-Jensen medium. Both protein-enriched media were able to prevent drug carryover effects, but the use of 7H11 medium supplemented with 5% BSA is preferred for practical reasons.

Time-dependent interaction between lopinavir/ritonavir and fexofenadine.

This study investigated the effect of single-dose and steady-state lopinavir/ritonavir on the exposure to fexofenadine, as a measure of P-glycoprotein activity. Sixteen volunteers (8 women) received single-dose oral fexofenadine 120 mg alone, in combination with single-dose ritonavir 100 mg or lopinavir/ritonavir 400/100 mg (randomized 1:1, stratified by sex), and in combination with steady-state lopinavir/ritonavir 400/100 mg twice daily. Single-dose ritonavir and lopinavir/ritonavir increased the area under the fexofenadine plasma concentration-time curve from 0 to infinity (AUC(infinity)) by 2.2- and 4.0-fold, respectively (P < .02). Steady-state lopinavir/ritonavir increased the fexofenadine AUC(infinity) by 2.9-fold. No changes were observed in the fexofenadine elimination half-life (P > .12). The fexofenadine AUC(infinity) was increased by lopinavir/ritonavir, likely due to increased bioavailability secondary to P-glycoprotein inhibition. After repeated administration of lopinavir/ritonavir, the interaction was attenuated compared to the single-dose effect, although a net inhibitory effect was maintained. Time-dependent inhibition of P-glycoprotein by lopinavir/ritonavir should be considered when P-glycoprotein substrates are coadministered.