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BACKGROUND The World Health Organization (WHO) 2019 antiretroviral treatment guidelines recommend use of optimal treatment regimens in all populations. Dolutegravir-based regimens are the preferred first-line and second-line treatment in infants and children with HIV 4 weeks of age and above. There is an urgent need for optimal pediatric formulations of dolutegravir as single-entity (SE) and fixed-dose combination (FDC) to ensure correct dosing and adherence for swallowing and palatability. This article outlines the chronology of dolutegravir pediatric formulation development as granules and conventional and dispersible tablets in a total of 5 pharmacokinetic studies evaluating the relative bioavailability of dolutegravir SE and FDC formulations in healthy adults. METHODS The relative bioavailability studies were 2-part, Phase I, open-label, randomized studies in healthy adults. Dolutegravir SE study compared conventional dolutegravir 50 and 25 mg with equivalent conventional 10-mg and dispersible 5-mg tablets, respectively. Subsequently, dolutegravir FDC study compared adult FDC of abacavir/dolutegravir/lamivudine and adult FDC of dolutegravir/lamivudine with their respective pediatric FDC formulations, taken as dispersion immediately or swallowed whole. RESULTS As observed in previous studies, dolutegravir administered as dispersion (granules/dispersible tablets) showed relatively higher bioavailability compared with conventional tablets. The bioavailability of dolutegravir dispersible tablets (both SE and FDC) was approximately 1.6-fold higher when compared with conventional tablets. In addition, the bioavailability of abacavir/lamivudine was not impacted by dispersible formulation. CONCLUSIONS These studies demonstrate the successful development of pediatric dolutegravir-containing formulations as SE and FDC that permit pediatric dosing in line with WHO recommendations.

Background The GSK3732394 multivalent protein was developed as a novel, long-acting, antiretroviral biologic treatment regimen with three independent, non–cross-resistant mechanisms for inhibiting HIV-1 entry. Methods A single-centre, Phase 1, double-blind, randomized, placebo-controlled study was conducted in healthy volunteers, using a 2-part adaptive study design: in Part 1, participants were randomized to receive subcutaneous injection of GSK3732394 or placebo (3:1) as single ascending doses (10-mg starting dose); in Part 2, participants were intended to receive multiple ascending doses. Primary and secondary objectives included safety, pharmacokinetics (PK) and pharmacodynamics (PD; cluster of differentiation four receptor occupancy [CD4 RO]) of GSK3732394 in healthy adults; PK/PD results in healthy volunteers were used to project HIV-1 treatment success. Results The most frequently reported adverse event was injection site reactions (ISRs; 8/18 [44%]). Most ISRs were mild (Grade 1–2; n = 7); one participant experienced a Grade 3 ISR (erythema ≥10 cm). All ISRs were delayed in onset (after Day 10). GSK3732394 demonstrated linear PK across all cohorts. Clearance was faster than expected, and PK/PD results were lower than expected, with the maximum dose investigated (80 mg) achieving mean trough CD4 RO of ∼25% on Day 7. The study was terminated as the PK/PD model linking PK and CD4 RO indicated that the maximum planned doses would not achieve the desired therapeutic profile. Conclusions This study demonstrated successful deployment of PK/PD dose relationships in the design and conduct of clinical trials by leveraging the findings toward predicting probability of success, resulting in appropriate early termination ( ClinicalTrials.gov , NCT03984812).

Pharmacokinetics, safety, and tolerability of abacavir 600 mg/dolutegravir 50 mg/lamivudine 300 mg were assessed in this phase 1, single‐arm, open‐label, single‐dose study in fasted healthy male (n = 4) and female (n = 8) participants of Japanese heritage. Participants received a single dose of abacavir 600 mg/dolutegravir 50 mg/lamivudine 300 mg after an 8‐hour fast, with safety assessments and blood samples for pharmacokinetic parameters collected through 72 hours after dosing. Geometric mean maximum plasma concentrations were 5.22 μg/mL (time to maximum concentration [tmax], 1.01 hours) for abacavir, 4.13 μg/mL (tmax, 3.50 hours) for dolutegravir, and 3.35 μg/mL (tmax, 2.98 hours) for lamivudine. Geometric mean area under the concentration‐time curve values were 18.20, 71.60, and 16.60 μg • h/mL for abacavir, dolutegravir, and lamivudine, respectively. No adverse events were reported, and no clinically significant findings were observed in laboratory values, physical examinations, or 12‐lead electrocardiographic parameters. Single‐tablet administration of abacavir 600 mg/dolutegravir 50 mg/lamivudine 300 mg was well tolerated in Japanese participants. Exposure to abacavir and lamivudine was comparable with that seen in previous studies. A modest increase in exposure to dolutegravir vs previous clinical studies was observed but is not expected to impact the clinical management of HIV‐1 or increase the risk for adverse events.

Dolutegravir 50 mg (DTG) and rilpivirine 25 mg (RPV) are a newly approved 2-drug regimen for the treatment of HIV in virally suppressed patients. A 2-part study evaluated the relative bioavailability and food effect of five experimental fixed-dose combination (FDC) tablet formulations of DTG/RPV. When given with a moderate- or high-fat meal, the absorption of both DTG and RPV was increased, resulting in higher exposures. As per product labelling, DTG/RPV FDC should be taken with a meal.

Introduction Tafenoquine has been recently registered for the prevention of relapse in Plasmodium vivax malaria. Objective This study assessed the pharmacodynamic effects of 300-mg single-dose tafenoquine on the retina. Methods This phase I, prospective, multicenter, randomized, single-masked, placebo-controlled, parallel-group study was conducted between 2 February 2016 and 14 September 2017 at three US study centers. Adult healthy volunteers were randomized (2:1) to receive either a single 300-mg oral dose of tafenoquine or matched placebo on day 1. Ophthalmic assessments, including spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF), were conducted at baseline and day 90 and evaluated for pre-determined endpoints by an independent, masked reading center. Results One subject in each group met the composite primary endpoint for retinal changes identified with SD-OCT or FAF, i.e., one out of 306 (0.3%) with tafenoquine, one out of 161 (0.6%) with placebo. Both cases had unilateral focal ellipsoid zone disruption at day 90 with no effect on best-corrected visual acuity. The tafenoquine-treated subject had this abnormality at baseline, and was enrolled in error. There was no difference in ophthalmic safety between tafenoquine and placebo. Conclusion There was no evidence of any pharmacodynamic effect of 300-mg single-dose tafenoquine on the retina or any short-term clinically relevant effects on ophthalmic safety. This clinical trial is registered with ClinicalTrials.gov (identifier: NCT02658435). Electronic supplementary material The online version of this article (10.1007/s40264-019-00839-w) contains supplementary material, which is available to authorized users.

In children aged ≤4 years, the relative bioavailability of lamivudine oral solution was 37% lower than that of a tablet formulation. An open‐label, four‐way crossover study was conducted in healthy adults to evaluate the effect of sorbitol, a common liquid excipient, on the pharmacokinetics of lamivudine oral solution (ClinicalTrials.gov identifier, NCT02634073). Sixteen subjects were randomized to one of four sequences consisting of four doses of lamivudine 300 mg (10 mg/mL) alone or with sorbitol 3.2, 10.2, or 13.4 g. Sorbitol 3.2, 10.2, and 13.4 g decreased lamivudine maximum concentration (C max) by 28%, 52%, and 55% and area under the concentration–time curve from time 0 to 24 h (AUC0‐24) by 20%, 39%, and 44%, respectively. Three subjects (19%) reported five nonserious adverse events (one drug‐related). The dose‐dependent effects of sorbitol on lamivudine C max and AUC0‐24 reveal an absorption‐based interaction that may decrease lamivudine exposure in patients coadministered sorbitol‐containing medicines.

A complete 2-drug regimen of dolutegravir at 50 mg and rilpivirine at 25 mg was approved to treat HIV-1 infection in virologically suppressed patients after demonstrating acceptable efficacy and tolerability. This study investigated the bioequivalence and pharmacokinetics of the fixed-dose combination tablet compared with those of separate tablets. Secondary endpoints were the tolerability and safety of the fixed-dose combination tablet. In this open-label, randomized-sequence, 2-way crossover trial, single doses of the fixed-dose combination tablet (the test treatment) and the combination of separate tablets (the reference treatment) were administered to healthy adults after a moderate-fat meal, with a 21-day washout between treatments. Pharmacokinetic samples were collected through 12 days after dosing. The primary endpoints were the area under the plasma concentration-time curve (AUC) and the maximum concentration of drug in plasma (Cmax). The study employed a prespecified sample size reestimation based on a blind midpoint review of Cmax variability to update the enrollment size to achieve statistical power. Of 118 participants enrolled, 113 received both treatments and underwent pharmacokinetic assessment. The 90% confidence intervals for the geometric least-squares mean ratios for the AUC from 0 h to infinity, the AUC from 0 h to the last quantifiable measurement, and Cmax (test treatment versus reference treatment) were within the bioequivalence range of 0.80 to 1.25 for both drugs, indicating bioequivalence. In this study, a single dose of either treatment was well tolerated overall, with 4% (n = 5) and 3% (n = 3) of participants reporting adverse events considered related to the test and reference treatments, respectively. The dolutegravir-rilpivirine fixed-dose combination tablet is bioequivalent to a combination of separate tablets, and no new safety signals emerged. (This study has been registered at ClinicalTrials.gov under identifier NCT02741557.).

A combination of fluticasone furoate (FF) and umeclidinium (UMEC) has been considered for development for the treatment of asthma. The primary objectives were to investigate the plasma and urine pharmacokinetics (PK) of FF/UMEC in combination compared with FF and UMEC monotherapies.This randomized, double-blind, three-period crossover, single-center study in healthy volunteers assessed the PK of FF 400 mcg and UMEC 500 mcg administered separately and in combination (four inhalations of FF/UMEC 100/125 mcg, FF 100 mcg, or UMEC 125 mcg) via dual-strip dry powder inhaler. Subjects were randomized based on codes generated using a validated computerized system (Randall, GlaxoSmithKline).Eighteen subjects were enrolled; 17 received all three scheduled doses of study medication. Plasma FF and UMEC concentrations peaked at 0.5 and 0.08 h post-dose, respectively, for FF/UMEC and the monotherapies. FF and UMEC co-administration resulted in slightly lower or similar systemic exposure for both drugs versus the monotherapies. In post hoc sensitivity analyses (performed because two subjects administered inhalations incorrectly), the ratio of adjusted geometric means (maximum plasma concentration and area under the curve) was closer to unity than in the planned analyses. Cumulative urinary UMEC excretion (Ae) was similar for FF/UMEC and UMEC. Post hoc sensitivity analyses on Ae(0-24) suggested a small carryover effect but results were similar to those of the population as a whole. Urinary UMEC excretion following FF/UMEC was low (~1.5% over 24 h) and unlikely to have impacted upon PK comparisons. Three adverse events were reported; none were severe or led to withdrawal. There were no clinically significant effects on electrocardiogram, vital sign, or laboratory parameters.Fluticasone furoate and umeclidinium co-administration was well tolerated and was not associated with meaningful changes in systemic or urinary PK versus the monotherapies.GlaxoSmithKline.

GSK2982772 is a highly selective inhibitor of receptor‐interacting protein kinase 1 (RIPK1) being developed to treat chronic inflammatory diseases. This first‐in‐human study evaluated safety, tolerability, pharmacokinetics (PK), and exploratory pharmacodynamics (PD) of GSK2982772 administered orally to healthy male volunteers. This was a Phase I, randomized, placebo‐controlled, double‐blind study. In Part A, subjects received single ascending doses of GSK2982772 (0.1‐120 mg) or placebo in a crossover design during each of 4 treatment periods. In Part B, subjects received repeat doses of GSK2982772 (20 mg once daily [QD] to up to 120 mg twice daily [BID]) or placebo for 14 days. Part C was an open‐label relative bioavailability study comparing 20‐mg tablets vs capsules. Safety, tolerability, pharmacokinetics (PK), RIPK1 target engagement (TE), and pharmacodynamics (PD) were assessed. The most common adverse events (AEs) were contact dermatitis and headache. Most AEs were mild in intensity, and there were no deaths or serious AEs. The PK of GSK2982772 was approximately linear over the dose range studied (up to 120 mg BID). There was no evidence of drug accumulation upon repeat dosing. Greater than 90% RIPK1 TE was achieved over a 24‐hour period for the 60‐mg and 120‐mg BID dosing regimens. Single and repeat doses of GSK2982772 were safe and well tolerated. PK profiles showed dose linearity. The high levels of RIPK1 TE support progression into Phase II clinical trials for further clinical development.