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Objectives: To characterize the population pharmacokinetics of the rilpivirine long-acting (LA) formulation after intramuscular administration.Methods: Rich and sparse rilpivirine plasma concentration data were obtained from seven clinical studies. In total, 18 261 rilpivirine samples were collected from 986 subjects (131 healthy subjects from Phase I studies and 855 people living with HIV from Phase IIb/III studies). Doses ranged from 300 to 1200 mg, as single-dose or multiple-dose regimens (every 4 or 8 weeks). In Phase III studies, an initiation injection of 900 mg followed by continuation injections of 600 mg every 4 weeks was used. Non-linear mixed-effects modelling was performed using NONMEM® software.Results: A one-compartment model with linear elimination and two parallel absorption pathways (fast and slow) with sequential zero-first-order processes adequately captured rilpivirine flip-flop pharmacokinetics after intramuscular administration of the LA formulation. The estimated apparent elimination half-life of rilpivirine LA was 200 days. None of the evaluated covariates (age, body weight, BMI, sex, race, health status and needle length) had a clinically relevant impact on rilpivirine pharmacokinetics.Conclusions: The population pharmacokinetic model suitably describes the time course and associated variability of rilpivirine plasma concentrations after rilpivirine LA intramuscular administration. The monthly regimen consists of an oral lead-in period (rilpivirine 25 mg tablets once daily for 4 weeks), followed by an initiation injection of 900 mg rilpivirine LA, then 600 mg rilpivirine LA continuation injections monthly. The absence of a clinically relevant effect of covariates on rilpivirine pharmacokinetics suggests that rilpivirine LA dose adjustments for specific subgroups are not warranted. [ABSTRACT FROM AUTHOR]

Rilpivirine (RPV, TMC278, Edurant®) is a next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI), which demonstrated high virologic response rates and non-inferiority versus efavirenz in two Phase III trials in HIV-infected patients through 96 weeks [,]. RPV has been shown to inhibit P-glycoprotein (P-gp) in vitro with an apparent IC50 of 9.2 µM (3.4 µg/mL). This study evaluated the in-vivo effect of steady-state RPV 25 mg once daily (qd) on the single-dose pharmacokinetics of the probe P-gp substrate digoxin. This was a Phase I, open-label, randomised, crossover trial in 22 HIV-negative volunteers. Participants received in one session a single 0.5 mg dose of digoxin, and in another session RPV 25 mg qd for 16 days with a single 0.5 mg dose of digoxin in the morning of Day 11. All study drugs were taken with a breakfast. Pharmacokinetic profiles of digoxin in plasma and urine were determined over 144 hours after dosing in each session. Steady-state RPV 24-hour pharmacokinetic profiles in plasma were determined on Day 11. Plasma and urine samples were analysed using validated LC-MS/MS methods. Pharmacokinetic parameters were calculated with non-compartmental methods. The least square (LS) means and associated 90% confidence intervals (CI) of treatment ratios were calculated based on log-transformed pharmacokinetic parameters. Safety and tolerability were assessed throughout the trial. Digoxin pharmacokinetic parameters and statistical results are summarised in . [ABSTRACT FROM AUTHOR]

An abstract of the article "Effect of intrinsic and extrinsic factors on the pharmacokinetics of TMC278 in antiretroviralnatve, HIV-1-infected patients in ECHO and THRIVE," by several authors including HM Crauwels, E van Schaick, and K Boven is presented.

Background: Simplified regimens for the treatment of human immunodeficiency virus type 1 (HIV-1) infection may increase patient satisfaction and facilitate adherence.Methods: In this phase 3, open-label, multicenter, noninferiority trial involving patients who had had plasma HIV-1 RNA levels of less than 50 copies per milliliter for at least 6 months while taking standard oral antiretroviral therapy, we randomly assigned participants (1:1) to either continue their oral therapy or switch to monthly intramuscular injections of long-acting cabotegravir, an HIV-1 integrase strand-transfer inhibitor, and long-acting rilpivirine, a nonnucleoside reverse-transcriptase inhibitor. The primary end point was the percentage of participants with an HIV-1 RNA level of 50 copies per milliliter or higher at week 48, determined with the use of the Food and Drug Administration snapshot algorithm.Results: Treatment was initiated in 308 participants per group. At week 48, HIV-1 RNA levels of 50 copies per milliliter or higher were found in 5 participants (1.6%) receiving long-acting therapy and in 3 (1.0%) receiving oral therapy (adjusted difference, 0.6 percentage points; 95% confidence interval [CI], -1.2 to 2.5), a result that met the criterion for noninferiority for the primary end point (noninferiority margin, 6 percentage points). An HIV-1 RNA level of less than 50 copies per milliliter at week 48 was found in 92.5% of participants receiving long-acting therapy and in 95.5% of those receiving oral therapy (adjusted difference, -3.0 percentage points; 95% CI, -6.7 to 0.7), a result that met the criterion for noninferiority for this end point (noninferiority margin, -10 percentage points). Virologic failure was confirmed in 3 participants who received long-acting therapy and 4 participants who received oral therapy. Adverse events were more common in the long-acting-therapy group and included injection-site pain, which occurred in 231 recipients (75%) of long-acting therapy and was mild or moderate in most cases; 1% withdrew because of this event. Serious adverse events were reported in no more than 5% of participants in each group.Conclusions: Monthly injections of long-acting cabotegravir and rilpivirine were noninferior to standard oral therapy for maintaining HIV-1 suppression. Injection-related adverse events were common but only infrequently led to medication withdrawal. (Funded by ViiV Healthcare and Janssen; ATLAS ClinicalTrials.gov number, NCT02951052.). [ABSTRACT FROM AUTHOR]

Background: Long-acting injectable regimens may simplify therapy for patients with human immunodeficiency virus type 1 (HIV-1) infection.Methods: We conducted a phase 3, randomized, open-label trial in which adults with HIV-1 infection who had not previously received antiretroviral therapy were given 20 weeks of daily oral induction therapy with dolutegravir-abacavir-lamivudine. Participants who had an HIV-1 RNA level of less than 50 copies per milliliter after 16 weeks were randomly assigned (1:1) to continue the current oral therapy or switch to oral cabotegravir plus rilpivirine for 1 month followed by monthly injections of long-acting cabotegravir plus rilpivirine. The primary end point was the percentage of participants who had an HIV-1 RNA level of 50 copies per milliliter or higher at week 48 (Food and Drug Administration snapshot algorithm).Results: At week 48, an HIV-1 RNA level of 50 copies per milliliter or higher was found in 6 of 283 participants (2.1%) who received long-acting therapy and in 7 of 283 (2.5%) who received oral therapy (adjusted difference, -0.4 percentage points; 95% confidence interval [CI], -2.8 to 2.1), a result that met the criterion for noninferiority for the primary end point (margin, 6 percentage points). An HIV-1 RNA level of less than 50 copies per milliliter at week 48 was found in 93.6% who received long-acting therapy and in 93.3% who received oral therapy (adjusted difference, 0.4 percentage points; 95% CI, -3.7 to 4.5), a result that met the criterion for noninferiority for this end point (margin, -10 percentage points). Of the participants who received long-acting therapy, 86% reported injection-site reactions (median duration, 3 days; mild or moderate severity, 99% of cases); 4 participants withdrew from the trial for injection-related reasons. Grade 3 or higher adverse events and events that met liver-related stopping criteria occurred in 11% and 2%, respectively, who received long-acting therapy and in 4% and 1% who received oral therapy. Treatment satisfaction increased after participants switched to long-acting therapy; 91% preferred long-acting therapy at week 48.Conclusions: Therapy with long-acting cabotegravir plus rilpivirine was noninferior to oral therapy with dolutegravir-abacavir-lamivudine with regard to maintaining HIV-1 suppression. Injection-site reactions were common. (Funded by ViiV Healthcare and Janssen; FLAIR ClinicalTrials.gov number, NCT02938520.). [ABSTRACT FROM AUTHOR]

Objectives This phase I healthy volunteer study ( NCT01031589) was carried out to investigate the safety/tolerability and pharmacokinetics of a rilpivirine ( RPV; TMC278) long-acting ( LA) formulation after single and multiple intramuscular ( IM) injections. Methods In the first part of the study, which had an open-label design, a single RPV LA IM injection (300 mg/mL) of 300 ( n = 6) or 600 ( n = 5) mg was given to the volunteers. In the second part of the study, which had a double-blind, randomized, placebo-controlled design, three RPV LA IM injections (one every 4 weeks) at 1200/600/600 mg ( n = 6) or placebo ( n = 2) were given. Safety and local tolerability were monitored. RPV plasma concentrations were analysed up to 28 days after injection or until they were < 20 ng/mL. Results Grade 1/2 RPV-related adverse events in the 300, 600 and 1200/600/600 mg groups were: rash (zero, one and one subject, respectively, the last of whom discontinued participation in the study); musculoskeletal stiffness (three, zero and zero subjects, respectively); injection site reactions (one, two and two subjects, respectively). After one injection of 300, 600 or 1200 mg RPV LA, the mean (standard deviation) maximum plasma concentration was 39 (25), 48 (13) and 140 (16) ng/mL, and the mean (standard deviation) area under the concentration-time curve (28 days) was 17 090 (8907), 25 240 (8184) and 55 350 (13 550) ng h/mL, respectively. RPV pharmacokinetics were largely comparable after the 1200 mg loading dose and both 600 mg injections of RPV LA. The mean (standard deviation) RPV plasma concentration across the 28-day dosing interval after the last injection in the 1200/600/600 mg group was 79 (19) ng/mL. Conclusions Single and multiple IM injections of RPV LA demonstrated favourable local/systemic tolerability in healthy volunteers. RPV pharmacokinetics suggested that clinically relevant plasma concentrations can be achieved with this LA formulation. [ABSTRACT FROM AUTHOR]

Objectives A week 48 efficacy and safety analysis with respect to gender and race was conducted using pooled data from the phase III, double-blind, double-dummy efficacy comparison in treatment-naïve, HIV-infected subjects of TMC278 and efavirenz ( ECHO) and TMC278 against HIV, in a once-daily regimen versus efavirenz ( THRIVE) trials. Methods Treatment-naïve, HIV-1-infected adults were randomized to receive rilpivirine ( RPV; TMC278) 25 mg once a day (qd), or efavirenz ( EFV) 600 mg qd, plus tenofovir/emtricitabine ( ECHO) or tenofovir/emtricitabine, zidovudine/lamivudine or abacavir/lamivudine ( THRIVE). Results A total of 1368 participants (76% male and 61% White, of those with available race data) were randomized and treated. No gender-related differences in response rate (percentage of patients with HIV-1 viral load < 50 HIV-1 RNA copies/ mL, using an intent-to-treat, time-to-loss-of-virological-response algorithm) were observed ( RPV: men, 85%; women, 83%; EFV: men, 82%; women, 83%). Response rates were lower in Black compared with Asian and White participants ( RPV: 75% vs. 95% and 85%, respectively; EFV: 74% vs. 93% and 83%, respectively); this finding was mostly a result of higher discontinuation and virological failure rates in Black patients. Safety findings were generally similar across race and gender subgroups. However, nausea occurred more commonly in women than in men in both treatment groups. In men, diarrhoea was more frequent in the EFV group, and abnormal dreams/nightmares were more frequent in men in both the EFV and RPV groups. Conclusions Overall response rates were high for both RPV and EFV. No gender differences were observed. However, response rates were lower among Black patients, regardless of treatment group. Gender appeared to influence the incidence of gastrointestinal adverse events and abnormal dreams/nightmares for both treatments. [ABSTRACT FROM AUTHOR]

An abstract of the research paper "Pooled Week 48 Safety and Efficacy Results From the ECHO and THRIVE phase III Trials Comparing TMC278 vs EFV in Treatment-Naïve, HIV-1-infected Patients," by C. Cohen and colleagues which was presented at the Tenth International Congress on Drug Therapy in HIV Infection held at Glasgow, Scotland from November 7-11, 2010 is presented.