The treatment of HIV-1 infection has dramatically changed over the last decade with the introduction of new drugs and regimens that are generally effective and well tolerated.1,2 Despite these advances, adherence continues to be a major factor affecting treatment response.3 Novel regimens that require administration less frequently than once daily would be beneficial for selected patients with difficulty adhering to their antiretroviral (ARV) medications.
GSK1265744 (744) is an HIV integrase inhibitor and analog of dolutegravir. 744 dosed orally at 5 and 30 mg/d demonstrated >2.2 log10 copies per milliliter reduction in plasma HIV-1 RNA in a 10-day monotherapy trial.4 744 possesses a number of pharmaceutical properties that enable it to be formulated as a long-acting (LA) injection, including low solubility, a low oral daily dose (<50 mg/d), and low metabolic clearance. Single doses of 200–800 mg administered intramuscularly (IM) or subcutaneously (SC) in healthy subjects have demonstrated prolonged exposures with therapeutically relevant concentrations observed for ≥30 days.5 TMC278 LA is an investigational nanosuspension for IM injection of rilpivirine (RPV), a marketed nonnucleoside reverse transcriptase inhibitor for oral use. The pharmacokinetic (PK) profile of RPV LA also demonstrates an extended apparent half-life and plasma concentrations similar to those observed with oral RPV, enabling dosing once monthly or at longer intervals.6
Concomitant administration of 744 LA with RPV LA has the potential to be the first injectable ARV regimen with a dosing interval of at least 30 days in contrast to the daily dosing requirement with current oral therapy. Adherence to such a regimen would be expected to result in long-term suppression of viral load and an increase in convenience for those patients willing and able to tolerate injectable therapy. The objective of this study was to evaluate the PK, safety, and tolerability of repeat doses of 744 LA alone and with RPV LA.
This was a 2-center, phase 1, randomized, open-label, repeat-dose study in healthy adults. Subjects of either sex were eligible to enroll if they were between the ages of 18 and 64 years (inclusive) and had a body mass index within the range of 18.5–31.0 kg/m2. Screening procedures included medical history, physical examination, and laboratory tests. Women of childbearing potential could enroll if they had a negative pregnancy test at screening and predose and agreed to use acceptable contraception methods during the study. Subjects were ineligible if they had a history of hypersensitivity to any of the study medications, a positive prestudy hepatitis B surface antigen, a positive hepatitis C antibody result within 3 months of screening, a positive test for HIV antibody, history of liver disease, or known hepatobiliary abnormalities. Pregnant or lactating women were not eligible. Use of prescription or nonprescription drugs, including vitamins, herbal, and dietary supplements, was precluded within 7 days (or 14 days if the drug was a potential enzyme inducer) before the first dose of study medication unless determined by the investigator and sponsor that the medication would not be expected to alter the PK of either investigational drug. The study was conducted in accordance with good clinical practice procedures, all applicable regulatory requirements, and the guiding principles of the Declaration of Helsinki. Written informed consent was obtained from all subjects, and the institutional review boards of the study sites approved the protocol.
The study design is shown in Figure 1. Subjects received a 14-day lead-in of oral 744 (30 mg/d) to assess safety and tolerability followed by a 7-day washout period before 744 LA injectable administration. Subjects were then randomized into 4 cohorts: (1) 744 LA 800 mg IM followed by 3 monthly doses of 200 mg SC (744 LA 800 mg IM/200 mg SC), (2) 744 LA 800 mg IM followed by 3 monthly doses of 200 mg IM (744 LA 800 mg IM/200 mg IM), (3) 744 LA 800 mg IM followed by 3 monthly doses of 400 mg IM (744 LA 800 mg IM/400 mg IM), or (4) 744 LA 800 mg IM followed by a second injection of 800 mg IM 12 weeks later (744 LA 800 mg IM every 12 weeks). Cohort 2 also received separate IM doses of RPV LA at month 3 (1200 mg) and month 4 (900 mg) (744 LA 800 mg IM/200 mg IM with RPV LA 1200 mg IM/900 mg IM), whereas cohort 3 also received separate IM doses of RPV LA at month 3 (1200 mg) and month 4 (600 mg) (744 LA 800 mg IM/400 mg IM with RPV LA 1200 mg IM/600 mg IM).
744 LA was provided as a 200-mg/mL suspension administered as an IM (gluteal) or SC (abdominal) injection. RPV LA was provided as a 300-mg/mL suspension and administered as an IM (gluteal) injection. Each drug was administered separately. Doses of 744 LA 800 mg and RPV LA 1200 mg were administered as 2 injections of 2 mL each at different gluteal locations. Lower doses were administered as a single injection. Each injection location was recorded, and injection reactions were assessed separately. Injection site examination included an assessment of pain, tenderness, pruritus, warmth, infections, rash, erythema, swelling, induration, and nodules (granulomas or cysts). If present, each of these injection site reactions (ISRs) was graded on a scale of 1–4, with 1 being mild (no or minimal limitation) and 4 being severe (inability to perform basic self-care function or hospitalization other than emergency room required for management). Subjects completed an ISR diary until the last study visit.
Serial plasma samples for PK analysis were collected over 24 hours on day 14 of oral dosing. Additional samples were collected before each injection and then on days 1, 3, 7, 14, 21, and 28 after the injection. Additional samples were collected on days 56 and 84 after the last injection. Safety was assessed throughout the trial by adverse event (AE) assessment, laboratory tests, electrocardiograms, vital signs, and physical examination. Subjects were also required to keep a diary to describe any ISRs. They also completed a tolerability questionnaire on injection days and then again 2 weeks after injections. Subjects rated their comfort level on a scale of 1 (very intolerable) to 5 (very tolerable). Abbreviated safety follow-up visits were conducted at weeks 20, 28, 36, 44, and 52 following the last injection.
744 plasma concentrations were determined by Bioanalytical Sciences and Toxicokinetics, Drug Metabolism and Pharmacokinetics of GlaxoSmithKline using a validated high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) assay with a TurboIonSpray (AB Sciex, Framingham, MA) interface and positive ion multiple-reaction monitoring following extraction from plasma by protein precipitation using acetonitrile. Data were acquired and processed using the proprietary software application Analyst (version 1.4 or higher; MDS Sciex, Concord, ON, Canada) and the GlaxoSmithKline Study Management System, SMS2000 (version 2.3; GlaxoSmithKline, Research Triangle Park, NC). The internal standard was [13C2H215N]-744. This method was validated over the range 10–10,000 ng/mL. Quality control samples were included in each run at 30, 800, and 8000 ng/mL. On the basis of the results of the QC sample analysis, the bias ranged from 4.3% to 9.4% and precision ranged from 2.4% to 3.9%.
Rilpivirine plasma concentrations were determined by Frontage Laboratories (Shanghai) Co., Ltd. (Zhangjiang High-Tech Park, Shanghai, P.R. China) under the management of Janssen Research & Development, a division of Janssen Pharmaceutica N.V. (Beerse, Belgium), using a validated HPLC–MS/MS method following protein precipitation.7 Data were acquired and quantified using the proprietary software application Analyst (version 1.4.2; Applied Biosystems, Foster City, CA) and Watson 7.3 LIMS (Thermo Scientific Waltham, MA). The internal standard was JNJ-ZBJOB358. This method was validated over the range 1–2000 ng/mL. QC samples were included in each run at 2.73, 54.6, and 1560 ng/mL. On the basis of the results of the QC sample analysis, the bias ranged from −5.9% to 2.6%, and intra-run and inter-run precision ranged from 0.4% to 6.8% and 3.1%–5.8%, respectively.
Individual plasma concentration–time data were analyzed with model 200 for extravascular administration of the Phoenix WinNonlin Professional software (version 5.2; Pharsight Corp, Mountain View, CA). Actual recorded sampling times for each individual profile were used to determine plasma 744 and RPV PK parameters, which included the area under the curve (AUC) from time 0 until the end of the dosage interval (AUC0–τ) using the linear-up/log-down approach to the trapezoidal rule, the observed maximum plasma concentration (Cmax), the time to observed maximum plasma concentration (tmax), and the plasma concentration at the end of the dosage interval (Cτ).
Descriptive statistics were used to describe the PK and safety of 744 LA and RPV LA. Summaries included n, mean, SD, median, minimum, and maximum for continuous variables; n and percent were used as summary statistics for categorical variables and geometric mean with associated 95% confidence interval, and the between-subject coefficient of variation (% CVb) for PK parameters.
Subject Disposition and Demographics
Forty-seven subjects were enrolled into the oral lead-in period, and 40 received at least 1 LA injection. Of the 7 subjects withdrawn before LA injection, 1 was withdrawn for an AE and 6 were withdrawn for reasons that were non–drug-related (such as conflicting work schedules). LA dosing was completed by 37 subjects. One subject withdrew because of a grade 1 rash that occurred 1 week after receiving his first injection and resolved within 5 days. Two others withdrew consent for non–drug-related reasons; 1 received 2 injections and 1 received 4 injections. Mean (SD) age was 39.5 (13.9) years, mean body mass index was 26.1 (2.9) kg/m2, and the majority of subjects were men (64%). Race was described as 74% white, 21% black, and 4% other.
Mean plasma 744 concentration–time profiles are shown in Figure 2. All regimens achieved therapeutically relevant plasma concentrations within 3 days after injection as defined by attaining mean plasma concentrations greater than 4-fold the protein binding–adjusted IC90 for wild-type HIV (0.66 μg/mL) and persisted until the end of the dosing interval. Accumulation over 4 monthly doses was observed for the 800 mg/400 mg IM dose regimen while the other regimens seemed to be at or near steady state by the third month of dosing. PK parameters following the last dose of 744 LA and RPV LA in each cohort are shown in Table 1. Geometric mean PK parameters for 744 LA were similar between groups receiving IM and SC doses of 200 mg. Cmax and AUC0–τ were generally linear between the 200-mg and 400-mg 744 LA IM doses.
Mean plasma RPV concentration–time profiles following RPV LA injections are shown in Figure 3. The RPV LA 1200 mg/600 mg in cohort 3 and RPV LA 1200 mg/900 mg in cohort 2 achieved similar concentrations at the end of the last dosing interval although the geometric mean Cmax was higher in the group receiving the RPV LA 1200 mg IM/900 mg IM doses (Table 1).
Within this trial, variability was low to moderate for both compounds with the CV% for AUC0–τ ranging from 23%–52% for 744 and 34%–35% for RPV.
744 LA was generally well tolerated when administered alone or with RPV LA. One subject experienced a serious AE requiring hospitalization for appendicitis that was considered unrelated to study drug. All other AEs were mild or moderate in severity. ISRs were the most commonly observed AEs and reported in the majority of subjects. Table 2 describes the incidence of ISRs by subject cohort and Table 3 provides data by ISR event and treatment. There were no grade 3 or 4 ISRs. Pain was the most common ISR; the majority of ISRs were reported to be mild in severity (Table 3). The median duration of pain was less than 7 days and similar between 744 LA and RPV LA dosing. Erythema, nodules, induration, and warmth at the injection site were also reported. The incidence of nodules was higher in those receiving SC 744 LA than in subjects with IM injections of either 744 LA or RPV LA. Biopsies were performed on the nodules of 3 subjects. One of these received 744 LA quarterly dosing and 2 received 744 LA by the SC route. These nodules resolved spontaneously without treatment. The overall incidence of ISRs was similar between the RPV LA cohorts that received their dose as a 2-mL injection (cohort 3; 8/10) and as a 3-mL injection (cohort 2; 7/9).
There were few drug-related AEs that were not associated with ISRs. Headache was reported in 3 (30%) of 10 subjects in cohort 1 (744 LA 800 mg IM/200 mg SC) and 2 (20%) of 10 subjects in cohort 2 (744 LA 800 mg IM/200 mg IM with RPV LA 1200 mg IM/900 mg IM). Abdominal pain was reported in 2 (20%) of 10 subjects in cohort 4 (744 LA 800 mg IM every 12 weeks). All other AEs were reported in at most 1 subject. No clinically significant trends in laboratory abnormalities, electrocardiograms, or vital signs were observed.
Injections were rated as well tolerated by subjects, with median scores on the tolerability questionnaire of ≥4.5 (5 = very tolerable) at all time points during the study.
This study represents the initial safety and tolerability evaluation of repeated injections of 744 LA and the first concomitant administration of 744 LA and RPV LA as parenteral nanosuspensions. The goal of such a 2-drug injectable regimen administered at intervals of 4 weeks or longer is to maintain viral suppression in subjects who achieved viral loads of <50 copies per milliliter on an oral, standard of care ARV regimen. The combination of 744 and RPV as a 2-drug oral maintenance regimen is currently being evaluated in the LATTE study (ClinicalTrials.gov identifier NCT01641809). In this dose-ranging study of oral 744 plus 2 nucleoside reverse transcriptase inhibitors in treatment-naive subjects, those who achieve viral loads <50 copies per milliliter after 24 weeks are switched to an oral maintenance regimen of 744 and RPV 25 mg/d. Oral 744 doses of 10, 30, and 60 mg/d, each combined with RPV 25 mg/d, maintained viral suppression below 50 copies per milliliter at 24 weeks of 2-drug maintenance therapy in 93% of subjects, with a similar response rate across the different doses of 744.8 These data support the planned evaluation of 744 LA and RPV LA for the maintenance of virologic suppression. The injectable form of this 2-drug regimen will minimize nonadherence to a daily dosing regimen as a contributing factor to virologic failure. This regimen does, however, require that patients come in for recurrent clinic visits to receive their injections. Adherence to the regimen is still considered important to maintain virologic success, but the emphasis shifts from adherence to daily oral administration to compliance with clinic visits.
A 744 LA loading dose of 800 mg IM followed by monthly injections of 200 mg or 400 mg provided plasma concentrations at the end of the dosing interval that exceed the protein binding–adjusted IC90 by at least 4-fold. The loading dose is required to rapidly achieve therapeutic concentrations and shorten the time to steady state. These plasma concentrations also fall between those observed with oral 744 doses of 5 mg and 30 mg once daily, both of which were similarly effective in monotherapy studies.4 Variability in this study was low to moderate with the LA form of 744 and similar to that of the oral dose (Table 1). Specific factors that might affect the PK of 744 LA, such as gender, body size, and physical activity, are being evaluated. All injections were administered in the gluteal muscle because of the volume of the injections.
RPV LA was administered with 744 LA during months 3 and 4 of the study in cohorts 2 and 3. Although mean maximum plasma concentrations were higher for the 900-mg dose compared with the 600-mg dose, these data demonstrate that both doses provided similar plasma concentrations at the end of the second dosing interval. In phase 3 studies, the approved oral dose of RPV 25 mg/d provided a mean Cτ of 80 ng/mL and a Cavg (average RPV plasma concentration within a 24-hour dosing interval) of 100 ng/mL.9 Both RPV LA doses provided comparable exposures to these values at the end of the dosing interval (Fig. 3). The similarity of Cτ with the 600-mg and 800-mg IM doses is likely related to administration of the same loading dose with detectable concentrations before the next dose being given. Exposures were overlapping between the 2 doses; however, separation may have been observed with more doses.
Two routes of parenteral administration were explored for 744 LA dosing. The PKs were similar between SC and IM doses of 200 mg. However, nodules were reported more frequently with SC dosing. In addition, RPV LA is being developed for IM injection only; as a result, this mode of administration is planned for future studies with this 2-drug regimen. Although the SC route may be more amenable to self-administration, the availability of this route for only 1 of the drugs in the regimen may not provide a significant advantage for HIV treatment.
ISRs were common but generally mild in severity, and no subject withdrew from the study because of an ISR. Tolerability questionnaires were administered throughout the study and subjects reported high scores (median values of ≥4.5 on a 5-point scale) at all collection times. The overall tolerability profile supports evaluation in long-term clinical studies. The injection volumes of 4 mL for 744 LA (200 mg/mL) and 4 mL for RPV LA (300 mg/mL) require a total of 4 injections for loading doses of 744 LA 800 mg and RPV LA 1200 mg, respectively (2 injections for each drug), but the maintenance dose would then require only 2 injections every month (or less frequently with a longer dosing interval). Pain at the injection site was most commonly reported (along with erythema), but both were of short duration.
An oral lead-in period was used to demonstrate safety and tolerability of 744 in an individual subject before administration of the LA formulation. Given that plasma concentrations of 744 can be detectable for up to 52 weeks following injection, an oral dosing lead-in period could identify early acute drug toxicities that can be more easily managed by withdrawal of drug. Although some AEs (such as idiosyncratic reactions) are unpredictable and may not be detected with a short lead-in therapy, a 4- to 6-week course of oral therapy would be expected to detect the majority of acute drug reactions in individual subjects. Because RPV is an approved drug with a well-described safety profile and a low incidence of acute drug reactions, no short-term dosing of oral RPV was required before RPV LA injection. However, a short oral lead-in period is being used in an ongoing phase 2b study.
The 744 LA and RPV LA injections were generally well tolerated, and therapeutically relevant plasma concentrations of both drugs were achieved across all study cohorts. These results, along with data from the oral LATTE study,8 provide support for a study of this 2-drug, LA injectable regimen for maintenance of suppression in HIV-infected patients (LATTE-2; ClinicalTrials.gov identifier NCT02120352).
The authors wish to acknowledge Clint Smith for editorial assistance during the development of this manuscript.
1. Arribas JR, Eron J. Advances in antiretroviral therapy. Curr Opin HIV AIDS. 2013;8:341–349.
2. Llibre JM, Clotet B. Once-daily single-tablet regimens: a long and winding road to excellence in antiretroviral treatment. AIDS Rev. 2012;14:168–178.
3. Ammassari A, Trotta MP, Shalev N, et al.. Beyond virological suppression: the role of adherence in the late HAART era. Antivir Ther. 2012;17:785–792.
4. Spreen W, Min S, Ford SL, et al.. Pharmacokinetics
, safety, and monotherapy antiviral activity of GSK1265744
, an HIV integrase strand transfer inhibitor. HIV Clin Trials. 2013;14:192–203.
5. Spreen W, Ford SL, Chen S, et al.. GSK1265744 pharmacokinetics
in plasma and tissue following single-dose long-acting
injectable administration in healthy subjects. J Acquir Immune Defic Syndr. 2014; [Epub ahead of print; August 21, 2014].
6. van 't Klooster G, Hoeben E, Borghys H, et al.. Pharmacokinetics
and disposition of rilpivirine
as a long-acting
injectable antiretroviral formulation. Antimicrob Agents Chemother. 2010;54:2042–2050.
7. Crauwels HM, Van Heeswijk RP, Buelens A, et al.. Impact of food and different meal types on the pharmacokinetics
. J Clin Pharmacol. 2013;53:834–840.
8. Margolis D, Brinson C, Eron J, et al.. 744 and rilpivirine
as two drug oral maintenance therapy: LAI116482 (LATTE) week 48 results. Abstract presented at: 21st Conference on Retroviruses and Opportunistic Infections; March 3–6, 2014; Boston, MA. Abstract 91LB.
9. Crauwels H, van Schaick E, van Heeswijk R, et al.. Effect of intrinsic and extrinsic factors on the pharmacokinetics
in antiretroviral-naive, HIV-1-infected patients in ECHO and THRIVE. Abstract presented at: 10th International Congress on Drug Therapy in HIV Infection; November 7–11, 2010; Glasgow, United Kingdom. Abstract P186.
Keywords:© 2014 by Lippincott Williams & Wilkins
long-acting; GSK1265744; rilpivirine; TMC278; injections; pharmacokinetics; nanosuspension