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Objectives: Long-acting formulations of cabotegravir (CAB) and rilpivirine (RPV) have demonstrated efficacy in Phase 3 studies. POLAR (NCT03639311) assessed antiviral activity and safety of CAB+RPV long-acting administered every 2 months (Q2M) in adults living with HIV-1 who previously received daily oral CAB+RPV in LATTE (NCT01641809). Design: A Phase 2b, multicenter, open-label, rollover study. Methods: LATTE participants with plasma HIV-1 RNA less than 50 copies/ml who completed at least 300 weeks on study were eligible. Participants elected to switch to either CAB+RPV long-acting Q2M or daily oral dolutegravir/RPV for maintenance of virologic suppression. The primary endpoint was the proportion of participants with HIV-1 RNA greater than or equal to 50 copies/ml at Month 12 (M12) per the Food and Drug Administration Snapshot algorithm. The incidence of confirmed virologic failure (CVF, two consecutive HIV-1 RNA measurements greater than or equal to 200 copies/ml), as well as safety, laboratory, and patient-reported outcomes (HIV Treatment Satisfaction and preference questionnaires) were also assessed. Results: Of 97 participants enrolled, 90 chose to receive CAB+RPV long-acting and seven chose dolutegravir/RPV. At M12, no participant had HIV-1 RNA greater than or equal to 50 copies/ml or met the CVF criterion in either treatment group. No new safety signals were identified. Total treatment satisfaction was high at Baseline and remained stable through M12 across both treatment groups. Overall, 88% (n = 77/88) of long-acting arm participants preferred CAB+RPV long-acting to oral CAB+RPV. Conclusion: CAB+RPV long-acting maintained virologic suppression in participants who had previously received daily oral CAB+RPV for at least 5 years in LATTE, with a favorable safety profile. Most participants preferred CAB+RPV long-acting to their prior oral CAB+RPV regimen at M12.

Objective: We had previously shown that long-acting cabotegravir (CAB-LA) injections fully protected macaques from vaginal simian HIV (SHIV) infection. Here, we reassessed CAB-LA efficacy in the presence of depot medroxyprogesterone acetate and multiple sexually transmitted infections (STIs) that are known to increase HIV susceptibility in women. Design: Two macaque models of increasing vaginal STI severity were used for efficacy assessment. Methods: The first study (n = 11) used a double STI model that had repeated exposures to two vaginal STI, Chlamydia trachomatis and Trichomonas vaginalis. Six animals were CAB-LA treated and five were controls. The second study (n = 9) included a triple STI model with repeated exposures to C. trachomatis, T. vaginalis and syphilis, and the contraceptive, depot medroxyprogesterone acetate (DMPA). Six animals were CAB-LA treated and three were controls. All animals received up to 14 vaginal SHIV challenges. A survival analysis was performed to compare the number of SHIV challenges to infection in the drug-treated group compared with untreated controls over time. Results: All six CAB-LA treated animals in both models, the double STI or the triple STI-DMPA model, remained protected after 14 SHIV vaginal challenges, while the untreated animals became SHIV-infected after a median of two challenges (log-rank P

Background: ATLAS (NCT02951052), a phase 3, multicenter, open-label study, demonstrated that switching to injectable cabotegravir (CAB) with rilpivirine (RPV) long-acting dosed every 4 weeks was noninferior at week (W) 48 to continuing three-drug daily oral current antiretroviral therapy (CAR). Results from the W 96 analysis are presented. Methods and design: Participants completing W 52 of ATLAS were given the option to withdraw, transition to ATLAS-2M (NCT03299049), or enter an Extension Phase to continue long-acting therapy (Long-acting arm) or switch from CAR to long-acting therapy (Switch arm). Endpoints assessed at W 96 included proportion of participants with plasma HIV-1 RNA less than 50 copies/ml, incidence of confirmed virologic failure (CVF; two consecutive HIV-1 RNA ≥200 copies/ml), safety and tolerability, pharmacokinetics, and patient-reported outcomes. Results: Most participants completing the Maintenance Phase transitioned to ATLAS-2M (88%, n = 502/572). Overall, 52 participants were included in the W 96 analysis of ATLAS; of these, 100% (n = 23/23) and 97% (n = 28/29) in the Long-acting and Switch arms had plasma HIV-1 RNA less than 50 copies/ml at W 96, respectively. One participant had plasma HIV-1 RNA 50 copies/ml or higher in the Switch arm (173 copies/ml). No participants met the CVF criterion during the Extension Phase. No new safety signals were identified. All Switch arm participants surveyed preferred long-acting therapy to their previous daily oral regimen (100%, n = 27/27). Conclusion: In this subgroup of ATLAS, 98% (n = 51/52) of participants at the Extension Phase W 96 analysis maintained virologic suppression with long-acting therapy. Safety, efficacy, and participant preference results support the therapeutic potential of long-acting CAB+RPV treatment for virologically suppressed people living with HIV-1.

Background Advances in HIV-1 therapeutics have led to the development of a range of daily oral treatment regimens, which share similar high efficacy rates. Consequently, more emphasis is being placed upon the individual’s experience of treatment and impact on quality of life. The first long-acting injectable antiretroviral therapy for HIV-1 (long-acting cabotegravir + rilpivirine [CAB + RPV LA]) may address challenges associated with oral treatment for HIV-1, such as stigma, pill burden/fatigue, drug–food interactions, and adherence. Patient-reported outcomes (PROs) collected in an HIV-1 clinical trial (ATLAS-2M; NCT03299049) comparing participants’ experience with two dosing regimens (every 4 weeks [Q4W] vs. every 8 weeks [Q8W]) of CAB + RPV LA are presented herein. Methods PRO endpoints evaluated through 48 weeks of therapy included treatment satisfaction (HIV Treatment Satisfaction Questionnaire [HIVTSQ]), treatment acceptance (“General Acceptance” domain of the Chronic Treatment Acceptance [ACCEPT®] questionnaire), acceptability of injections (Perception of Injection [PIN] questionnaire), treatment preference (questionnaire), and reasons for switching to/continuing long-acting therapy (exploratory endpoint; questionnaire). Participants were randomized 1:1 to receive CAB + RPV LA Q8W or Q4W. Results were stratified by prior CAB + RPV exposure in either preplanned or post hoc analyses. Results Overall, 1045 participants were randomized to the Q8W (n = 522) and Q4W (n = 523) regimens; 37% (n = 391/1045) had previously received CAB + RPV in ATLAS. For participants without prior CAB + RPV exposure, large increases from baseline were reported in treatment satisfaction in both long-acting arms (HIVTSQ status version), with Q8W dosing statistically significantly favored at Weeks 24 (p = 0.036) and 48 (p = 0.004). Additionally, improvements from baseline were also observed in the “General Acceptance” domain of the ACCEPT questionnaire in both long-acting arms for participants without prior CAB + RPV exposure; however, no statistically significant difference was observed between arms at either timepoint (Week 24, p = 0.379; Week 48, p = 0.525). Significant improvements (p, Plain Language Summary Developments in HIV-1 treatment have resulted in effective daily oral medications. However, life-long pill taking can come with several challenges. These include having a daily reminder of living with HIV-1. Treatment satisfaction is important to consider when evaluating a new medicine. This is because it can affect people’s quality of life. The purpose of this study was to evaluate people’s experiences with the first long-acting injectable medicine for HIV-1. The medicine is called cabotegravir + rilpivirine long-acting (CAB + RPV LA). Over approximately 1 year, this study measured people’s satisfaction and experiences while receiving injections of CAB + RPV LA. Injections were given either every 4 weeks or every 8 weeks. The study included people who had never had CAB + RPV LA, as well as people who were already receiving CAB + RPV LA. For people new to CAB + RPV LA, their satisfaction increased compared with their previous medication. They also had improvements in their experiences of injection site reactions throughout the study. For people who were already receiving CAB + RPV LA, their high satisfaction with this treatment and tolerability of injection site reactions were maintained over time. Overall, improvements were similar between people receiving injections every 4 weeks and people receiving injections every 8 weeks. People with experience of both injection schedules tended to prefer to receive injections every 8 weeks. These results show that CAB + RPV LA can provide quality-of-life improvements for people who have HIV-1. Supplementary Information The online version contains supplementary material available at 10.1007/s40271-021-00524-0.

Current antiretroviral therapy (ART) consists of a combination of two or more oral agents from at least two drug classes, such as an integrase strand transfer inhibitor (INSTI) as well as one or two nucleoside reverse transcriptase inhibitors (NRTIs) [1,2]. Cabotegravir (CAB), an INSTI, and rilpivirine (RPV), a non-NRTI (NNRTI), have been developed as the first long-acting, injectable, two-drug ART regimen administered intramuscularly monthly or every 2 months for the maintenance of virologic suppression in people living with HIV-1 [3,4]. Long-acting CAB+RPV is indicated for the treatment of HIV-1 infection in virologically suppressed adults (HIV-1 RNA

Phase 3 clinical studies showed non-inferiority of long-acting intramuscular cabotegravir and rilpivirine dosed every 4 weeks to oral antiretroviral therapy. Important phase 2 results of every 8 weeks dosing, and supportive modelling, underpin further evaluation of every 8 weeks dosing in this trial, which has the potential to offer greater convenience. Our objective was to compare the week 48 antiviral efficacy of cabotegravir plus rilpivirine long-acting dosed every 8 weeks with that of every 4 weeks dosing.ATLAS-2M is an ongoing, randomised, multicentre (13 countries; Australia, Argentina, Canada, France, Germany, Italy, Mexico, Russia, South Africa, South Korea, Spain, Sweden, and the USA), open-label, phase 3b, non-inferiority study of cabotegravir plus rilpivirine long-acting maintenance therapy administered intramuscularly every 8 weeks (cabotegravir 600 mg plus rilpivirine 900 mg) or every 4 weeks (cabotegravir 400 mg plus rilpivirine 600 mg) to treatment-experienced adults living with HIV-1. Eligible newly recruited individuals must have received an uninterrupted first or second oral standard-of-care regimen for at least 6 months without virological failure and be aged 18 years or older. Eligible participants from the ATLAS trial, from both the oral standard-of-care and long-acting groups, must have completed the 52-week comparative phase with an ATLAS-2M screening plasma HIV-1 RNA less than 50 copies per mL. Participants were randomly assigned 1:1 to receive cabotegravir plus rilpivirine long-acting every 8 weeks or every 4 weeks. The randomisation schedule was generated by means of the GlaxoSmithKline validated randomisation software RANDALL NG. The primary endpoint at week 48 was HIV-1 RNA ≥50 copies per mL (Snapshot, intention-to-treat exposed), with a non-inferiority margin of 4%. The trial is registered at ClinicalTrials.gov, NCT03299049 and is ongoing.Screening occurred between Oct 27, 2017, and May 31, 2018. Of 1149 individuals screened, 1045 participants were randomised to the every 8 weeks (n=522) or every 4 weeks (n=523) groups; 37% (n=391) transitioned from every 4 weeks cabotegravir plus rilpivirine long-acting in ATLAS. Median participant age was 42 years (IQR 34-50); 27% (n=280) female at birth; 73% (n=763) white race. Cabotegravir plus rilpivirine long-acting every 8 weeks was non-inferior to dosing every 4 weeks (HIV-1 RNA ≥50 copies per mL; 2% vs 1%) with an adjusted treatment difference of 0·8 (95% CI -0·6-2·2). There were eight (2%, every 8 weeks group) and two (1%, every 4 weeks group) confirmed virological failures (two sequential measures ≥200 copies per mL). For the every 8 weeks group, five (63%) of eight had archived non-nucleoside reverse transcriptase inhibitor resistance-associated mutations to rilpivirine at baseline. The safety profile was similar between dosing groups, with 844 (81%) of 1045 participants having adverse events (excluding injection site reactions); no treatment-related deaths occurred.The efficacy and safety profiles of dosing every 8 weeks and dosing every 4 weeks were similar. These results support the use of cabotegravir plus rilpivirine long-acting administered every 2 months as a therapeutic option for people living with HIV-1.ViiV Healthcare and Janssen.

The phase 3 ATLAS and FLAIR studies demonstrated that maintenance with Long-Acting (LA) intramuscular cabotegravir and rilpivirine is non-inferior in efficacy to current antiretroviral (CAR) oral therapy. Both studies utilized Patient-Reported Outcome instruments to measure treatment satisfaction (HIVTSQ) and acceptance (ACCEPT general domain), health status (SF-12), injection tolerability/acceptance (PIN), and treatment preference. In pooled analyses, LA-treated patients (n = 591) demonstrated greater mean improvements from baseline than the CAR group (n = 591) in treatment satisfaction (Week 44, + 3.9 vs. +0.5 HIVTSQs-points; p

The FLAIR study demonstrated noninferiority of monthly long-acting cabotegravir + rilpivirine versus daily oral dolutegravir/abacavir/lamivudine for maintaining virologic suppression. Three participants who received long-acting therapy had confirmed virologic failure (CVF) at Week 48, and all had HIV-1 that was originally classified as subtype A1 and contained the baseline integrase polymorphism L74I; updated classification algorithms reclassified all 3 as HIV-1 subtype A6. Retrospectively, the impact of L74I on

BackgroundSafe and effective long-acting injectable agents for preexposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection are needed to increase the options for preventing HIV infection.MethodsWe conducted a randomized, double-blind, double-dummy, noninferiority trial to compare long-acting injectable cabotegravir (CAB-LA, an integrase strand-transfer inhibitor [INSTI]) at a dose of 600 mg, given intramuscularly every 8 weeks, with daily oral tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) for the prevention of HIV infection in at-risk cisgender men who have sex with men (MSM) and in at-risk transgender women who have sex with men. Participants were randomly assigned (1:1) to receive one of the two regimens and were followed for 153 weeks. HIV testing and safety evaluations were performed. The primary end point was incident HIV infection.ResultsThe intention-to-treat population included 4566 participants who underwent randomization; 570 (12.5%) identified as transgender women, and the median age was 26 years (interquartile range, 22 to 32). The trial was stopped early for efficacy on review of the results of the first preplanned interim end-point analysis. Among 1698 participants from the United States, 845 (49.8%) identified as Black. Incident HIV infection occurred in 52 participants: 13 in the cabotegravir group (incidence, 0.41 per 100 person-years) and 39 in the TDF-FTC group (incidence, 1.22 per 100 person-years) (hazard ratio, 0.34; 95% confidence interval, 0.18 to 0.62). The effect was consistent across prespecified subgroups. Injection-site reactions were reported in 81.4% of the participants in the cabotegravir group and in 31.3% of those in the TDF-FTC group. In the participants in whom HIV infection was diagnosed after exposure to CAB-LA, INSTI resistance and delays in the detection of HIV infection were noted. No safety concerns were identified.ConclusionsCAB-LA was superior to daily oral TDF-FTC in preventing HIV infection among MSM and transgender women. Strategies are needed to prevent INSTI resistance in cases of CAB-LA PrEP failure. (Funded by the National Institute of Allergy and Infectious Diseases and others; HPTN 083 ClinicalTrials.gov number, NCT02720094.).

Background: Long-acting (LA) injectable antiretroviral therapy (ART) is a novel modality currently under development as an alternative to daily oral ART.Objective: The LATTE-2 study (ClinicalTrials...

A long-acting injectable formulation of the HIV integrase inhibitor cabotegravir (CAB-LA) is currently in clinical development for PrEP. Although the long plasma half-life of CAB-LA is an important attribute for PrEP, it also raises concerns about drug resistance emergence if someone becomes infected with HIV, or if PrEP is initiated during undiagnosed acute infection. Here we use a macaque model of SHIV infection to model risks of drug resistance to CAB-LA PrEP. Six macaques infected with SHIV received CAB-LA before seroconversion. We show integrase mutations G118R, E92G/Q, or G140R in plasma from 3/6 macaques as early as day 57, and identify G118R and E92Q in viruses from vaginal and rectal fluids. G118R and G140R confer > 800-fold resistance to CAB and cross-resistance to all licensed integrase inhibitors. Our results emphasize the need for appropriate HIV testing strategies before and possibly shortly after initiating CAB LA PrEP to exclude acute infection. Long-acting formulation of the integrase inhibitor cabotegravir (CAB LA) is in clinical development for HIV pre-exposure prophylaxis (PrEP). Here, using a SHIV macaque model, the authors show emergence of integrase mutations associated to CAB LA PrEP that confer pan-integrase inhibitor resistance.

This study investigates the impact of severe renal impairment on the pharmacokinetics of cabotegravir, an investigational HIV‐1 integrase inhibitor. This was a phase I, open‐label, parallel‐group, multicenter study conducted in 8 participants with severe renal impairment (creatinine clearance 90 mL/min; 2 women/group; 6 men/group) matched for sex, age (±10 years), and body mass index (±25%). Participants received a single 30‐mg oral cabotegravir tablet to determine total and unbound plasma cabotegravir concentrations. Arithmetic and geometric least squares means were calculated, and cabotegravir noncompartmental pharmacokinetic parameters were compared using geometric least squares mean ratios with 90% confidence intervals. Safety was assessed throughout the study. Geometric least squares mean ratios (90% confidence intervals) were 0.97 (0.84–1.14) for area under the plasma concentration‐time curve extrapolated to infinity, 1.01 (0.87–1.17) for maximum observed plasma concentration, 1.31 (0.84–2.03) for unbound cabotegravir 2 hours after dosing, and 1.51 (1.19–1.92) for unbound cabotegravir 24 hours after dosing. All adverse events were grade 1, except grade 3 lipase elevation in a participant with renal impairment. Severe renal impairment did not impact plasma cabotegravir exposure, and cabotegravir may be administered without dose adjustment in renal impairment among patients not receiving renal replacement.

Cabotegravir is an investigational integrase inhibitor in development for the treatment and pre‐exposure prophylaxis of HIV‐1 infection. Liver disease is a major cause of morbidity and mortality in HIV‐infected individuals and can impact the pharmacokinetics (PK) of HIV medications. This phase 1 study evaluated the PK of cabotegravir in individuals with moderate hepatic impairment (n = 8) versus healthy controls (n = 8). Participants received a single oral cabotegravir 30‐mg tablet and underwent PK sampling to determine total and unbound plasma cabotegravir concentrations. Calculated geometric least‐squares mean ratios (90% confidence intervals) for individuals with hepatic impairment versus healthy controls were 0.73 (0.50‐1.06) for AUC0‐∞, 0.69 (0.51‐0.93) for Cmax, 1.40 (0.80‐2.46) for unbound concentration (CU) 2 hours postdose, 1.55 (0.82‐2.94) for CU at 24 hours, 2.14 (1.57‐2.90) for unbound fraction (FU) at 2 hours, and 1.90 (1.14‐3.18) for FU at 24 hours. Adverse events (AEs) occurred in 2 individuals with hepatic impairment and 3 healthy controls and were grade 1/2 in severity. No participant discontinued because of AEs. Increased FU resulted in a modest decrease in total plasma exposure not considered clinically relevant. We conclude that cabotegravir may be administered without dose adjustment in patients with mild to moderate hepatic impairment.

Aims Cabotegravir is an integrase strand transfer inhibitor in clinical development as long-acting (LA) injectable HIV preexposure prophylaxis. Methods This phase I study assessed pharmacokinetics of cabotegravir in plasma and anatomical sites associated with sexual HIV-1 transmission after repeated oral and single intramuscular (IM) LA dosing in healthy adults. Following a 28-day oral lead-in period of cabotegravir 30 mg and a washout period of 14-42 days, participants were administered a single ultrasound-guided gluteal IM cabotegravir LA 600-mg injection. The study objective was to characterize cabotegravir concentrations in plasma, cervical, vaginal and rectal tissues, and cervicovaginal and rectal fluids and up to Week 12 after IM injection. Results Nineteen participants enrolled and 16 completed the study through Week 52. Cabotegravir was detected in plasma and all tissues and fluids. Median plasma cabotegravir concentrations exceeded the in vitro protein-adjusted 90% maximal inhibitory concentration through Week 12. Median tissue- and fluid-to-plasma cabotegravir concentration ratios across all visits were 0.32 for rectal fluid and 0.08-0.16 for other tissues and fluids. Adjusted R2 coefficients between cabotegravir concentrations in plasma and cervical, vaginal and rectal tissues were 0.78, 0.79 and 0.90, respectively. Injection-site reactions were common (88% of participants) and were mostly grade 1 in intensity (82%). Two participants reported 11 non-drug-related serious adverse events. Conclusion Concentrations of cabotegravir in tissues and fluids were proportional to plasma over time, with strong correlations between tissue and plasma concentrations. Cabotegravir LA tissue-to-plasma ratios may be important for understanding its use as preexposure prophylaxis.

Previous work established non-inferiority of switching participants who were virologically suppressed from daily oral standard of care to monthly long-acting intramuscular injections of cabotegravir plus rilpivirine over 96 weeks following a cabotegravir plus rilpivirine oral lead-in. Here, we report an evaluation of switching participants from standard of care oral regimens to long-acting cabotegravir plus rilpivirine via direct-to-injection or oral lead-in pathways.This study reports the week 124 results of the FLAIR study, an ongoing phase 3, randomised, open-label, multicentre (11 countries) trial. Antiretroviral therapy (ART)-naive participants who were virologically suppressed (HIV-1 RNA50 copies per mL) during the 20-week induction phase with standard of care were randomly assigned (1:1) to continue the standard of care oral regimen or switch to long-acting cabotegravir plus rilpivirine (283 per group) in the 100-week maintenance phase. Randomisation was stratified by sex at birth and baseline (pre-induction) HIV-1 RNA (100 000 or ≥100 000 copies per mL). Participants randomly assigned to long-acting therapy at baseline received a cabotegravir (30 mg) plus rilpivirine (25 mg) once daily oral lead-in for at least 4 weeks before first injection and could choose to continue long-acting cabotegravir (400 mg) plus rilpivirine (600 mg) every 4 weeks from week 100 or withdraw. At week 100, participants in the oral comparator ART group, in discussion with the investigator, could elect to switch to long-acting therapy (extension switch population), either direct-to-injection or with a 4 week oral lead-in (oral lead-in group), or withdraw. Week 124 endpoints included plasma HIV-1 RNA 50 or more copies per mL and less than 50 copies per mL (US Food and Drug Administration [FDA] Snapshot), confirmed virological failure (two consecutive HIV-1 RNA ≥200 copies per mL), and safety and tolerability. The study is registered at ClinicalTrials.gov, NCT02938520.Screening occurred between Oct 27, 2016, and March 24, 2017. At week 100, 232 (92%) of 253 participants transitioned to long-acting cabotegravir plus rilpivirine in the extension phase (111 [48%] in the direct-to-injection group and 121 [52%] in the oral lead-in group; extension switch population). 243 (86%) of the 283 who were randomly assigned to the long-acting therapy group continued the long-acting regimen into the extension phase. One (1%) participant in each extension switch group had 50 or more HIV-1 RNA copies per mL; 110 (99%) participants in the direct-to-injection group and 113 (93%) participants in the oral lead-in group remained suppressed (HIV-1 RNA50 copies per mL) at the week 124 Snapshot. The lower suppression rates in the oral lead-in group were driven by non-virological reasons. For participants in the randomly assigned long-acting group, 227 (80%) of 283 participants remained suppressed; at the week 124 Snapshot, 14 (5%) participants had HIV-1 RNA 50 or more copies per mL, including five additional participants since the week 96 analysis. The remaining 42 (15%) participants in the randomly assigned long-acting group had no virological data. Adverse events leading to withdrawal were infrequent, occurring in three (1%) participants in the extension switch population (one in the direct-to-injection group and two in the oral lead-in group) after 24 weeks of cabotegravir plus rilpivirine therapy, and 15 (5%) participants in the randomly assigned long-acting group up to 124 weeks of therapy. No deaths occurred in the extension phase. Overall, cabotegravir plus rilpivirine adverse event type, severity, and frequency were similar across all groups. Injection site reactions were the most common adverse event, occurring after 914 (21%) of 4442 injections in the extension switch population and 3732 (21%) of 17 392 injections in the randomly assigned long-acting group. Injection site reactions were mostly classified as mild-to-moderate in severity and decreased in incidence over time. Four (2%) of 232 participants in the extension switch population and seven (2%) of 283 in the randomly assigned long-acting group withdrew due to injection-related reasons.After 24 weeks of follow-up, switching to long-acting treatment with or without an oral lead-in phase had similar safety, tolerability, and efficacy, supporting future evaluation of the simpler direct-to-injection approach. The week 124 results for participants randomly assigned originally to the long-acting therapy show long-acting cabotegravir plus rilpivirine remains a durable maintenance therapy with a favourable safety profile.ViiV Healthcare and Janssen ResearchDevelopment.

Summary Background Long-acting cabotegravir and rilpivirine administered monthly or every 2 months might address the challenges associated with daily oral antiretroviral therapy. The ATLAS-2M week 48 results showed non-inferiority of long-acting cabotegravir and rilpivirine administered every 8 weeks compared with that of every 4 weeks. In this study, we report the efficacy, safety, and tolerability results from the week 96 analysis. Methods ATLAS-2M is a randomised, multicentre, open-label, phase 3b, non-inferiority trial conducted in 13 countries, evaluating the safety and efficacy of maintenance treatment with intramuscular injections of long-acting cabotegravir and rilpivirine, administered every 8 weeks versus every 4 weeks, to people living with HIV-1. Virologically suppressed adults with HIV-1, either already receiving intramuscular long-acting cabotegravir and rilpivirine every 4 weeks (ie, ATLAS study rollover participants) or oral standard of care, were randomly assigned (1:1), in an unblinded fashion, to receive either intramuscular long-acting cabotegravir (600 mg) and rilpivirine (900 mg) every 8 weeks (ie, the every 8-week dosing group) or intramuscular long-acting cabotegravir (400 mg) and rilpivirine (600 mg) every 4 weeks (ie, the every 4-week dosing group). Randomisation was generated using the GlaxoSmithKline-validated randomisation software RANDALL NG (version 1.3.3). The primary endpoint at week 48 was the proportion of participants with plasma HIV-1 RNA measurements of 50 copies per mL or more (ie, the US Food and Drug Administration [FDA] Snapshot algorithm), which has been published previously. Here, we present the week 96 results: the proportion of participants with plasma HIV-1 RNA measurements of less than 50 copies per mL (FDA Snapshot algorithm), with a non-inferiority margin of −10%; the proportion of participants with plasma HIV-1 RNA measurements of 50 copies per mL or more (FDA Snapshot algorithm), with a non-inferiority margin of 4%; the proportion of participants with protocol-defined confirmed virological failure (ie, two consecutive plasma HIV-1 RNA measurements ≥200 copies per mL); safety; pharmacokinetics; and tolerability. This study is registered with ClinicalTrials.gov , number NCT03299049 , and is currently ongoing. Findings Between Oct 27, 2017, and May 31, 2018, a total of 1149 participants were screened; of whom, 1049 (91%) were randomly assigned and 1045 (91%) initiated treatment (522 in the every 8-week dosing group and 523 in the every 4-week dosing group). The median age was 42 years (IQR 34–50). 280 (27%) of 1045 participants were assigned female at birth and 764 (73%) were white. At week 96 (FDA Snapshot algorithm), 11 (2%) of 522 participants in the every 8-week dosing group and six (1%) of 523 in the every 4-week dosing group had an HIV-1 RNA measurement of 50 copies per mL or more, with an adjusted treatment difference of 1·0 (95% CI −0·6 to 2·5), meeting the prespecified non-inferiority threshold of 4%; 475 (91%) of 522 participants in the every 8-week dosing group and 472 (90%) of 523 in the every 4-week dosing group maintained an HIV-1 RNA measurement of less than 50 copies per mL, with an adjusted treatment difference of 0·8 (95% CI −2·8 to 4·3), which met the prespecified non-inferiority threshold of −10%. One participant in the every 8-week dosing group met the confirmed virological failure criterion since the week 48 analysis at week 88, resulting in a total of nine participants in the every 8-week dosing group and two in the every 4-week dosing group having confirmed virological failure. No new safety signals were identified, and no treatment-related deaths occurred. Injection site reactions were the most common adverse event, occurring in 412 (79%) of 522 participants in the every 8-week dosing group and 400 (76%) of 523 in the every 4-week dosing group. Most injection site reactions were grade 1 or 2 (7453 [99%] of 7557 in both groups), with a median duration of 3 days (IQR 2–5). Interpretation Long-acting cabotegravir and rilpivirine dosed every 8 weeks had non-inferior efficacy compared with that of every 4 weeks through the 96-week analysis, with both regimens maintaining high levels of virological suppression. These results show the durable safety, efficacy, and acceptability of dosing long-acting cabotegravir and rilpivirine monthly and every 2 months as maintenance therapy for people living with HIV-1. Funding ViiV Healthcare and Janssen Research & Development.

Aim Cabotegravir long-acting (LA) intramuscular (IM) injection is being investigated for HIV preexposure prophylaxis due to its potent antiretroviral activity and infrequent dosing requirement. A subset of healthy adult volunteers participating in a phase I study assessing cabotegravir tissue pharmacokinetics underwent serial magnetic resonance imaging (MRI) to assess drug depot localization and kinetics following a single cabotegravir LA IM targeted injection. Methods Eight participants (four men, four women) were administered cabotegravir LA 600 mg under ultrasonographic-guided injection targeting the gluteal muscles. MRI was performed to determine injection-site location in gluteal muscle (IM), subcutaneous (SC) adipose tissue, and combined IM/SC compartments and to quantify drug depot characteristics, including volume and surface area, on Days 1 (≤2 hours postinjection), 3, and 8. Linear regression analysis examined correlations between MRI-derived parameters and plasma cabotegravir exposure metrics, including maximum observed concentration (Cmax ) and partial area under the concentration-time curve (AUC) through Weeks 4 and 8. Results Cabotegravir LA depot locations varied by participant and were identified in the IM compartment (n=2), combined IM/SC compartments (n=4), SC compartment (n=1), and retroperitoneal cavity (n=1). Although several MRI parameter and exposure metric correlations were determined, total depot surface area on Day 1 strongly correlated with plasma cabotegravir concentration at Days 3 and 8, Cmax , and partial AUC through Weeks 4 and 8. Conclusion MRI clearly delineated cabotegravir LA injection-site location and depot kinetics in healthy adults. Although injection-site variability was observed, drug depot surface area correlated with both plasma Cmax and partial AUC independently of anatomical distribution.

There is a need for more convenient, less frequent treatment to help address challenges associated with daily oral HIV treatment in people living with HIV, including stigma, pill burden, drug-food interactions, and adherence. The phase 3 ATLAS and FLAIR studies showed non-inferiority of long-acting cabotegravir and rilpivirine dosed every 4 weeks compared with standard oral therapy for the maintenance of virological suppression in adults with HIV-1 over 48 weeks. We present the 96-week findings.FLAIR is a randomised, phase 3, open-label, multicentre study done in 11 countries investigating whether switching to long-acting cabotegravir and rilpivirine is non-inferior to daily dolutegravir, abacavir, and lamivudine in virologically suppressed adults living with HIV-1. Antiretroviral therapy (ART)-naive participants received induction therapy with daily oral dolutegravir (50 mg), abacavir (600 mg), and lamivudine (300 mg) for 20 weeks. After 16 weeks, participants with less than 50 HIV-1 RNA copies per mL were randomly assigned (1:1) to continue the standard of care regimen (standard care group) or switch to receive daily oral cabotegravir 30 mg and rilpivirine 25 mg for at least 4 weeks followed by long-acting cabotegravir 400 mg and rilpivirine 600 mg, administered as two 2 mL intramuscular injections, every 4 weeks for at least 96 weeks (long-acting group). Randomisation was stratified by baseline (preinduction) HIV-1 RNA (100 000 or ≥100 000 copies per mL) and sex at birth and used GlaxoSmithKline-verified randomisation software (RandAll NG, version 1.3.3) for treatment assignment. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of 50 copies per mL or more assessed as per the US Food and Drug Administration (FDA) Snapshot algorithm at week 48, which has been reported previously. Here, we report the proportion of participants with 50 or more HIV-1 RNA copies per mL using the FDA Snapshot algorithm at week 96 (intention-to-treat population; non-inferiority margin 6%). The trial is registered with ClinicalTrials.gov, NCT02938520.Between Oct 27, 2016, and March 24, 2017, 809 participants were screened. 631 (78%) participants entered the induction phase and 566 (70%) were randomly assigned to either the standard care group (283 [50%] participants) or the long-acting group (283 [50%]). Median age was 34 years (IQR 29 to 43), 62 (11%) were 50 years or older, 127 (22%) were women (sex at birth), and 419 (74%) were white. At week 96, nine (3%) participants in each arm had 50 or more HIV-1 RNA copies per mL, with an adjusted difference of 0·0 (95% CI -2·9 to 2·9), consistent with non-inferiority established at week 48. Across both treatment groups, adverse events leading to withdrawal were infrequent (14 [5%] participants in the long-acting group and four [1%] in the standard care group). Injection site reactions were the most common adverse event, reported by 245 (88%) participants in the long-acting group; their frequency decreased over time. Median injection site reaction duration was 3 days (IQR 2 to 4), and 3082 (99%) of 3100 reactions were grade 1 or 2. No deaths occurred during the maintenance phase.The 96-week results reaffirm the 48-week results, showing long-acting cabotegravir and rilpivirine continued to be non-inferior compared with continuing a standard care regimen in adults with HIV-1 for the maintenance of viral suppression. These results support the durability of long-acting cabotegravir and rilpivirine, over an almost 2-year-long period, as a therapeutic option for virally suppressed adults with HIV-1.ViiV Healthcare and Janssen Research and Development.

Background Cabotegravir is an HIV integrase inhibitor in clinical development with both oral and long-acting (LA) injectable formulations. Cabotegravir is primarily metabolized by uridine 5′-diphospho-glucuronosyltransferase (UGT) 1A1, a known polymorphic enzyme with functional variants that can affect drug metabolism and exposure. Objectives To investigate the pharmacogenetic effects of the reduced-function alleles UGT1A1*6, UGT1A1*28 and/or UGT1A1*37 on steady-state pharmacokinetics (PK) and safety of oral cabotegravir (30 mg/day) and intramuscular cabotegravir LA (400 mg every 4 weeks or 600 mg every 8 weeks). Methods Plasma cabotegravir PK was assessed in 346 UGT-genotyped participants with and without UGT1A1 functional variants across six studies (four Phase I and two Phase II) of oral cabotegravir, including 215 HIV-infected participants who received oral cabotegravir followed by cabotegravir LA. Changes from baseline in total bilirubin and ALT were assessed in one study (LATTE; NCT01641809). Results Statistically significant (P Conclusions This modest increase in oral and parenteral cabotegravir exposure associated with a reduced function of UGT1A1 is not considered clinically relevant based on accumulated safety data; no dose adjustment is required.

Long-acting injectable regimens may simplify therapy for patients with human immunodeficiency virus type 1 (HIV-1) infection.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).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.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.).

Cabotegravir is an integrase inhibitor in clinical development for the treatment and prevention of HIV infection using oral tablets for short‐term, lead‐in use before subsequent administration of a long‐acting injectable formulation. This phase 1, single‐center, randomized, 2 × 2 crossover study evaluated the effect of a high‐fat meal on the pharmacokinetics (PK) of oral cabotegravir. Healthy adults received oral cabotegravir 30 mg as a single dose on 2 separate occasions, either after fasting or following a high‐fat meal (∼53% fat, ∼870 kcal). Safety evaluations and serial PK samples were collected, and a mixed‐effects model was used to determine within‐participant treatment comparison of noncompartmental PK parameters. Twenty‐four patients were enrolled and had a mean body mass index of 25.6 kg/m2; 67% were male. Compared with the fasting state, coadministration of cabotegravir with a high‐fat meal increased plasma cabotegravir area under the concentration‐time curve and maximal drug concentration, each by 14%. The slight 14% to 17% increase in exposure associated with a high‐fat, high‐calorie meal was not considered clinically significant. No grade 3/4 adverse events (AEs), drug‐related AEs, or AEs leading to discontinuation were reported.

Cabotegravir (GSK1265744) is an integrase strand transfer inhibitor in development as a long-acting (LA) intramuscular injectable suspension for HIV-1 pre-exposure prophylaxis (PrEP).We report participant outcomes from the phase IIa ECLAIR study related to tolerability, acceptability, and satisfaction of cabotegravir LA.The ECLAIR study (ClinicalTrials.gov identifier, NCT02076178) was a randomized, placebo-controlled study in healthy men not at high risk of acquiring HIV-1. Participants were randomized (5:1) to once-daily oral cabotegravir 30 mg or placebo tablets for 4 weeks, followed by gluteal intramuscular injections of cabotegravir LA 800 mg or saline placebo every 12 weeks. The primary objective was to evaluate the safety of cabotegravir LA over three injection cycles (to Week 41). Secondary objectives assessed the tolerability, satisfaction, and acceptability of cabotegravir LA.Among 115 participants who received injections in the cabotegravir (n = 94) and placebo (n = 21) groups, 93% (n = 87) and 95% (n = 20) completed the injection phase, respectively. Injection intolerability led to withdrawal in 4 participants (4%) receiving cabotegravir LA. The most frequently reported Grade ≥2 adverse event was injection-site pain. Most participants (74% [n = 67]) receiving consecutive injections favored cabotegravir LA vs oral cabotegravir. Most participants were satisfied with cabotegravir LA (75% [n = 64]), were willing to continue (79% [n = 68]), and would recommend (87% [n = 75]) the therapy.While Grade ≥2 injection-site pain was common, most participants reported overall satisfaction with and preference for cabotegravir LA, with few discontinuations due to injection intolerance. These findings support investigation of cabotegravir LA as an alternative to daily oral PrEP regimens.

Summary Background Cabotegravir (GSK1265744) is an HIV-1 integrase strand transfer inhibitor with potent antiviral activity and a long half-life when administered by injection that prevented simian-HIV infection upon repeat intrarectal challenge in male macaques. We aimed to assess the safety, tolerability, and pharmacokinetics of long-acting cabotegravir injections in healthy men not at high risk of HIV-1 infection. Methods We did this multicentre, double-blind, randomised, placebo-controlled, phase 2a trial at ten sites in the USA. Healthy men (aged 18–65 years) deemed not at high risk of acquiring HIV-1 at screening were randomly assigned (5:1), via computer-generated central randomisation schedules, to receive cabotegravir or placebo. Participants received oral cabotegravir 30 mg tablets or matching placebo once daily during a 4 week oral lead-in phase, followed by a 1 week washout period and, after safety assessment, three intramuscular injections of long-acting cabotegravir 800 mg or saline placebo at 12 week intervals. Study site staff and participants were masked to treatment assignment from enrolment through week 41 (time of the last injection). The primary endpoint was safety and tolerability from the first injection (week 5) to 12 weeks after the last injection. We did analysis in the safety population, defined as all individuals enrolled in the study who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov identifier, NCT02076178. Findings Between March 27, 2014, and Feb 23, 2016, we randomly assigned 127 participants to receive cabotegravir (n=106) or placebo (n=21); 126 (99%) participants comprised the safety population. Most participants were men who have sex with men (MSM; n=106 [83%]) and white (n=71 [56%]). 87 (82%) participants in the cabotegravir group and 20 (95%) participants in the placebo group completed the injection phase. Adverse events (n=7 [7%]) and injection intolerability (n=4 [4%]) were the main reasons for withdrawal in the cabotegravir group. The frequency of grade 2 or higher adverse events was higher in participants in the long-acting cabotegravir group (n=75 [80%]) than in those in the placebo group (n=10 [48%]; p=0·0049), mostly due to injection-site pain (n=55 [59%]). No significant differences were noted in concomitant medications, laboratory abnormalities, electrocardiogram, and vital sign assessments. Geometric mean trough plasma concentrations were 0·302 μg/mL (95% CI 0·237–0·385), 0·331 μg/mL (0·253–0·435), and 0·387 μg/mL (0·296–0·505) for injections one, two, and three, respectively, indicating lower than predicted exposure. The geometric mean apparent terminal phase half-life estimated after the third injection was 40 days. Two (2%) MSM acquired HIV-1 infection, one in the placebo group during the injection phase and one in the cabotegravir group 24 weeks after the final injection when cabotegravir exposure was well below the protein-binding-adjusted 90% inhibitory concentration. Interpretation Despite high incidence of transient, mild-to-moderate injection-site reactions, long-acting cabotegravir was well tolerated with an acceptable safety profile. Pharmacokinetic data suggest that 800 mg administered every 12 weeks is a suboptimal regimen; alternative dosing strategies are being investigated. Our findings support further investigation of long-acting injectable cabotegravir as an alternative to orally administered pre-exposure prophylaxis regimens. Funding ViiV Healthcare.

HIV remains a major global health concern, with the Joint United Nations Programme on HIV/AIDS and the World Health Organization (WHO) estimating the number of people living with HIV (PLWH) to be ∼37.9 million in 2018.1,2 Improvements in HIV treatment efficacy are reflected in the increases in longevity of PLWH.3 Despite this progress, the effectiveness of current antiretroviral therapy (ART) is challenged by the need to maintain high levels of adherence to sustain virologic suppression.4 Factors related to regimen complexity, such as dosing frequency and pill burden, food considerations, stigma, and drug–drug interactions between oral antiretrovirals and commonly prescribed non-ART medications, are reported to contribute to this challenge.4–6 Furthermore, the emotional burden of living with HIV may be compounded by daily oral pill taking and additional complexities.7 Therefore, there is considerable interest in developing long-acting (LA) treatments that can address many of these issues while simplifying ART for PLWH.8 The recommended ART regimen for PLWH generally consists of daily doses of either an oral 2-drug or 3-drug combination.9,10 This combination typically involves an integrase strand transfer inhibitor (INSTI) (dolutegravir as the sole INSTI preferred for use in adults in the WHO guidelines9 and either dolutegravir, bictegravir, or raltegravir preferred in the US Department of Health and Human Services guidelines10), in combination with 2 nucleoside reverse transcriptase inhibitors (NRTIs); although, a single NRTI (lamivudine) in combination with dolutegravir has recently been recommended as a 2-drug regimen in HIV treatment guidelines.10 Cabotegravir (CAB) (GSK1265744) is an investigational INSTI and structural analog of dolutegravir.11 Rilpivirine (RPV) is a next-generation non-NRTI (NNRTI) currently approved as a once-daily oral tablet to be used in combination with other antiretrovirals for the treatment of HIV infection.12,13 Both compounds are formulated as LA agents to be administered intramuscularly (IM), with oral formulations of RPV and a new formulation of CAB in development.13 These oral formulations have been used during an oral lead-in phase in the ATLAS14 and FLAIR15 studies to assess safety and tolerability before study participants transitioning to LA therapy with CAB and RPV. This 2-drug oral combination therapy of CAB and RPV was assessed in the LATTE ({"type":"clinical-trial","attrs":{"text":"NCT01641809","term_id":"NCT01641809"}}NCT01641809) study and shown to provide similar antiviral activity compared with efavirenz plus dual NRTIs.16 A single IM injection of CAB LA 800 mg or RPV LA 1200 mg demonstrated sustained mean or geometric mean plasma concentrations above their respective in vitro protein-adjusted 90% inhibitory concentrations (PA-IC90) at 32 weeks postdose for CAB LA17 (PA-IC90 0.166 μg/mL), and 24 weeks postdose for RPV LA18 (PA-IC90 12 ng/mL), providing rationale to investigate the 2 drugs as an LA combination regimen. In the LATTE-2 ({"type":"clinical-trial","attrs":{"text":"NCT02120352","term_id":"NCT02120352"}}NCT02120352) randomized, open-label phase 2b clinical trial, the injectable LA combination of CAB and RPV (CAB + RPV LA) as a 2-drug HIV-1 maintenance therapy, administered every 4 or 8 weeks, was similar to daily 3-drug oral therapy of CAB plus abacavir/lamivudine in maintaining viral suppression (plasma HIV-1 RNA

Background Cabotegravir (CAB) is an integrase strand transfer inhibitor in development as a long-acting injectable formulation, with an oral formulation used during a safety lead-in period. Tuberculosis (TB)–HIV coinfection is common, often requiring simultaneous treatment. Rifabutin (RBT) is an alternative antimycobacterial agent for TB and a moderate inducer of cytochrome P450 and UDP-glucuronosyltransferase isoenzymes. This study evaluated the impact of RBT on the pharmacokinetics (PK) of oral CAB. Methods In this Phase I, single-centre, open-label, two-period, fixed-sequence, drug interaction study, subjects received oral CAB 30 mg once daily for 14 days in period 1, and oral CAB plus RBT 300 mg once daily for 14 days in period 2. Serial PK sampling was performed on days 14 and 28. Geometric least squares (GLS) mean ratios with associated 90% CIs were calculated to compare CAB non-compartmental PK parameters following CAB+RBT versus CAB alone. Safety was also assessed. Results A total of 15 male subjects were enrolled and 12 completed all treatments. Comparing CAB+RBT with CAB alone, the GLS mean ratios (90% CIs) for CAB area under the concentration–time curve from time zero to the end of the dosing interval (AUC0–τ), maximum observed plasma concentration (Cmax) and concentration at the end of the dosing interval (Cτ) were 0.79 (0.74, 0.83), 0.83 (0.76, 0.90) and 0.74 (0.70, 0.78), respectively. 11 subjects reported 24 adverse events (AEs); 22 were reported with CAB+RBT (3 drug-related) and 2 with CAB alone (not drug-related). All AEs resolved by study end. Conclusions RBT had a modest impact on plasma CAB exposure following oral coadministration, resulting in overall plasma CAB trough exposures above the 10 mg oral dose shown to maintain viral suppression in HIV-1-infected subjects. Oral CAB can be coadministered with RBT without dosage adjustment.

A randomized, partial‐blind, repeat‐dose, 3‐period crossover study (NCT02027454) assessed the effect of cabotegravir on QT interval in healthy subjects. To achieve a supratherapeutic dose, each subject received cabotegravir 150 mg (30 mg × 5 tablets) every 12 hours for a total of 3 doses over 2 days, matching placebo (every 12 hours) over 2 days, or a single open‐label 400‐mg dose of the positive control moxifloxacin, with a 21‐day washout between treatments. Blood samples for pharmacokinetic analyses were collected up to 24 hours after the third dose on day 2. QT interval data were obtained by continuous Holter monitoring for approximately 24 hours at baseline (day ‐1) and from 2 hours before to 24 hours after the third dose on day 2. Plasma cabotegravir exposure was approximately 3‐fold above clinically relevant doses. After 3 doses of 150 mg of cabotegravir administered every 12 hours, all upper limits of 2‐sided 90% confidence intervals for ΔΔQTcF (difference in time‐matched change from baseline for QTcF between cabotegravir and placebo) were 450 milliseconds. There were no serious or grade 3 or 4 adverse events or clinically significant changes in laboratory values, vital signs, or electrocardiogram results. These data demonstrate that cabotegravir at a supratherapeutic dose had no effect on cardiac repolarization.

Background Cabotegravir (CAB) is a novel strand-transfer integrase inhibitor being developed for HIV treatment and prevention. CAB is formulated both as an immediate-release oral tablet for daily administration and as a long-acting injectable suspension (long-acting CAB [CAB LA]) for intramuscular (IM) administration, which delivers prolonged plasma exposure to the drug after IM injection. HIV Prevention Trials Network study 077 (HPTN 077) evaluated the safety, tolerability, and pharmacokinetics of CAB LA in HIV-uninfected males and females at 8 sites in Brazil, Malawi, South Africa, and the United States. Methods and findings HPTN 077 was a double-blind, placebo-controlled phase 2a trial. Healthy individuals age 18–65 years at low HIV risk were randomized (3:1) to receive CAB or placebo (PBO). In the initial oral phase, participants received 1 daily oral tablet (CAB or PBO) for 4 weeks. Those without safety concerns in the oral phase continued and received injections in the injection phase (Cohort 1: 3 injections of CAB LA 800 mg or 0.9% saline as PBO IM every 12 weeks for 3 injection cycles; Cohort 2: CAB LA 600 mg or PBO IM for 5 injection cycles; the first 2 injections in Cohort 2 were separated by 4 weeks, the rest by 8 weeks). The primary analysis included weeks 5 to 41 of study participation, encompassing the injection phase. The cohorts were enrolled sequentially. Primary outcomes were safety and tolerability. Secondary outcomes included pharmacokinetics and events occurring during the oral and injection phases. Between February 9, 2015, and May 27, 2016, the study screened 443 individuals and enrolled 110 participants in Cohort 1 and 89 eligible participants in Cohort 2. Participant population characteristics were as follows: 66% female at birth; median age 31 years; 27% non-Hispanic white, 41% non-Hispanic black, 24% Hispanic/Latino, 3% Asian, and 6% mixed/other; and 6 transgender men and 1 transgender woman. Twenty-two (11%) participants discontinued the oral study product; 6 of these were for clinical or laboratory adverse events (AEs). Of those who received at least 1 CAB LA injection, 80% of Cohort 1 and 92% of Cohort 2 participants completed all injections; injection course completion rates were not different from those in the PBO arm. Injection site reactions (ISRs) were common (92% of Cohort 1 and 88% of Cohort 2 participants who received CAB LA reported any ISR). ISRs were mostly Grade 1 (mild) to Grade 2 (moderate), and 1 ISR event (Cohort 1) led to product discontinuation. Grade 2 or higher ISRs were the only AEs reported more commonly among CAB LA recipients than PBO recipients. Two Grade 3 (severe) ISRs occurred in CAB recipients, 1 in each cohort, but did not lead to product discontinuation in either case. Seven incident sexually transmitted infections were diagnosed in 6 participants. One HIV infection occurred in a participant 48 weeks after last injection of CAB LA: CAB was not detectable in plasma both at the time of first reactive HIV test and at the study visit 12 weeks prior to the first reactive test. Participants in Cohort 2 (unlike Cohort 1) consistently met prespecified pharmacokinetic targets of at least 95% of participants maintaining CAB trough concentrations above PA-IC90, and 80% maintaining trough concentrations above 4× PA-IC90. Study limitations include a modest sample size, a short course of injections, and a low-risk study population. Conclusions In this study, CAB LA was well tolerated at the doses and dosing intervals used. ISRs were common, but infrequently led to product discontinuation. CAB LA 600 mg every 8 weeks met pharmacokinetic targets for both male and female study participants. The safety and pharmacokinetic results observed support the further development of CAB LA, and efficacy studies of CAB LA for HIV treatment and prevention are in progress. Trial registration ClinicalTrials.gov Registry: ClinicalTrials.gov Trial number: NCT02178800., In a phase 2a trial, Raphael Landovitz and colleagues investigate the safety of injectable cabotegravir in HIV-uninfected people, Author summary Why was this study done? Daily oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine is highly effective in preventing HIV infection when taken as prescribed, but adherence challenges have compromised full effectiveness in some populations. Cabotegravir (CAB) is a novel strand-transfer integrase inhibitor in development as a long-acting injectable preparation for HIV treatment and HIV prevention. HIV Prevention Trials Network study 077 (HPTN 077) aimed to establish the safety, tolerability, and pharmacokinetics of 2 dose/interval regimens of long-acting CAB in HIV-uninfected, low-risk individuals globally. What did the researchers do and find? Participants were randomized to active CAB or placebo. All participants received a 4-week daily oral lead-in of CAB or placebo, followed by a series of injections of CAB or placebo. Participants received either 800 mg as a split 2-ml injection every 12 weeks, or 600 mg as a single 3-ml injection every 8 weeks, after receiving 2 injections 4 weeks apart. We observed frequent injection site reactions (mostly injection site pain), and they were more common with CAB than placebo, but only led to discontinuation of injections in rare cases. No other safety concerns were noted. Pharmacokinetics, using target values from nonhuman primate simian/human immunodeficiency virus challenge prevention studies, support the 600 mg every 8 weeks dose, meeting prespecified targets. What do these findings mean? We found that CAB was generally well tolerated in HIV-uninfected males and females in diverse geographic locations. Injection site reactions, although frequent, did not deter continued dosing, albeit with short courses. Studies are ongoing to evaluate efficacy in at-risk populations and to further evaluate the safety of the 600 mg every 8 weeks dose.

1. Cabotegravir [(3S,11aR)-N-[(2,4-difluorophenyl)methyl]-6-hydroxy-3-methyl-5,7-dioxo-2,3,5,7,11,11a-hexahydro[1,3]oxazolo[3,2-a]pyrido[1,2-d]pyrazine-8-carboxamide] is an HIV-1 integrase inhibitor under development as a tablet for both oral lead-in therapy and long-acting (LA) injectable for intramuscular dosing. 2. Metabolism, pharmacokinetics and excretion were investigated in healthy human subjects who received either a single oral dose (28.2 mg) of [(14)C]cabotegravir in a mass balance study, or LA formulations of unlabeled cabotegravir (200-800 mg), intramuscularly or subcutaneously, in a separate study. Metabolism, distribution and excretion of [(14)C]cabotegravir were also investigated in mice, rats and monkeys. 3. Recovery of radioactivity in humans represented a mean total of 85.3% of the dose, including 26.8% in the urine. The mean apparent terminal phase half-life was similar for both cabotegravir and radioactivity, 39 h compared to 41 h. 4. Following oral, intramuscular and subcutaneous administration, cabotegravir was the major component in plasma and the glucuronic acid conjugate (M1) represented the predominant component in urine. Cabotegravir was present in bile along with its major metabolite (M1). 5. The primary metabolite of [(14)C]cabotegravir in mouse, rat and monkey was the same as that in human. In vitro phenotyping experiments demonstrated that cabotegravir was metabolized by UDP-glucuronosyltransferase (UGT) 1A1 and UGT1A9.

Drug-drug interactions between antiretroviral medications and rifampin complicate the treatment of HIV and tuberculosis coinfection. This study evaluated the effect of rifampin on the pharmacokinetics of oral cabotegravir, an integrase strand transfer inhibitor being investigated for long-acting treatment and prevention of HIV-1 infection. This was a phase I, single-center, open-label, fixed-sequence crossover study in healthy adults. The objective was to evaluate the effect of steady-state rifampin on the single-dose plasma pharmacokinetics of cabotegravir. Subjects received a single oral dose of cabotegravir (30 mg) on day 1 followed by plasma sampling on days 1 to 8. Treatment with once-daily oral rifampin (600 mg) occurred on days 8 to 28. Subjects received a second dose of 30 mg cabotegravir on day 21 followed by pharmacokinetic sampling on days 21 to 28. Fifteen subjects were enrolled and completed the study. Rifampin decreased the cabotegravir area under the concentration-time curve from 0 h to infinity and the half-life by 59% and 57%, respectively, whereas oral clearance was increased 2.4-fold. The maximum concentration of cabotegravir in plasma was unaffected by coadministration with rifampin. All adverse events were mild in severity, with chromaturia attributed to rifampin observed in all subjects. Rifampin induction of cabotegravir metabolism resulted in increased cabotegravir oral clearance and significantly decreased cabotegravir exposures. Rifampin is expected to increase cabotegravir clearance following long-acting injectable administration. Concomitant administration of rifampin with oral and long-acting formulations of cabotegravir is not recommended currently without further study. (This study has been registered at ClinicalTrials.gov under registration no. NCT02411435.)

BACKGROUND: GSK1265744 (744) is an HIV-1 integrase inhibitor in clinical development as a long-acting (LA) injectable formulation. This study evaluated plasma and tissue pharmacokinetics after single-dose administration of 744 LA administered by intramuscular (IM) or subcutaneous injections. METHODS: This was a phase I, open-label, 9-cohort, parallel study of 744 in healthy subjects. 744 was administered as a 200 mg/mL nanosuspension at doses of 100-800 mg IM and 100-400 mg subcutaneous. RESULTS: Eight (6 active and 2 placebo) male and female subjects participated in each of the first 7 cohorts. All 8 subjects, 4 males and 4 females, received active 744 LA in cohorts 8 and 9 and underwent rectal and cervicovaginal tissue sampling, respectively. Plasma pharmacokinetic sampling was performed for a minimum of 12 weeks or until 744 concentrations were ≤0.1 μg/mL. Rectal and cervicovaginal tissue biopsies were performed at weeks 2 and 8 (cohort 8) and weeks 4 and 12 (cohort 9). 744 LA was generally safe and well tolerated after single injections. A majority of subjects reported injection site reactions, all graded as mild in intensity. Plasma concentration-time profiles were prolonged with measureable concentrations up to 52 weeks after dosing. 744 LA 800 mg IM achieved mean concentrations above protein adjusted-IC90 for approximately 16 weeks. Rectal and cervicovaginal tissue concentrations ranged from

Dolutegravir (DTG) and GSK1265744 are HIV integrase inhibitors (INIs) in clinical development. The oral formulation of rilpivirine (RPV), a nonnucleoside reverse transcriptase inhibitor (NNRTI), has been approved for treatment-naive HIV infection. Long-acting depot injections of GSK1265744 and RPV are also being developed. This study evaluated the potential for drug interactions between RPV and these INIs. This phase 1, open-label, two-cohort, three-period, single-sequence crossover study evaluated oral coadministration of RPV with DTG or GSK1265744. Healthy subjects received DTG (50 mg every 24 h for 5 days) or GSK1265744 (30 mg every 24 h for 12 days) in period 1 followed by a washout, RPV (25 mg every 24 h for 11 or 12 days) in period 2, immediately followed by RPV (25 mg every 24 h) plus DTG (50 mg every 24 h) for 5 days or GSK1265744 (30 mg every 24 h) for 12 days in period 3. Steady-state pharmacokinetic (PK) parameters were estimated using noncompartmental analysis of data collected on the last day of each period. The combinations of RPV and DTG ( n = 16) and of RPV and GSK1265744 ( n = 11) were well tolerated; no grade 3 or 4 adverse events (AEs) or AE-related discontinuations were observed. The 90% confidence intervals for the area under the curve from time zero until the end of the dosage interval [AUC 0–τ ] and maximum concentration of drug in serum ( C max ) geometric mean ratios were within 0.8 to 1.25. Following administration of DTG + RPV, DTG and RPV C τ increased by 22% and 21%, respectively. Following administration of GSK1265744 + RPV, RPV C τ decreased 8%. DTG and GSK1265744 can be administered with RPV without dosage adjustment for either agent. These results support coadministration of RPV with DTG or GSK1265744 as either oral or long-acting depot injection regimens. (This study has been registered at ClinicalTrials.gov under registration no. NCT01467531.)

GSK2336805 is an orally bioavailable hepatitis C virus (HCV) inhibitor working through an NS5A-mediated mechanism. This first-time-in-human study was conducted to assess the safety, tolerability, pharmacokinetics, metabolism, and efficacy of GSK2336805 in healthy subjects and subjects infected with HCV genotype 1. We performed a three-part, randomized, double-blind, placebo-controlled study in 46 healthy subjects and 23 HCV-infected subjects. After an overnight fast, healthy subjects received GSK2336805 as 10 mg, 30 mg, 30 mg plus food, and 60 mg in a single dose and 10 mg (7 days), 30 mg (7 days), and 75 mg (14 days) in a once-daily multiple dose. Subjects with HCV received GSK2336805 as a 1- to 120-mg single dose. In subjects with HCV, reductions in HCV RNA were observed within 4 h and a single dose of GSK2336805 of ≥10 mg resulted in a statistically significant ≥2-log reduction in HCV RNA compared with placebo at 24 h postdose. GSK2336805 was readily absorbed in all subjects, and the half-life ( t 1/2 ) was suitable for once-daily dosing. Administration of GSK2336805 with food had no effect on plasma GSK2336805 exposure; however, absorption was delayed, with a median t max (time to maximum concentration of drug in serum) of 4.5 versus 2.0 h. Twenty subjects who received GSK2336805 experienced mild to moderate adverse events; none were serious. GSK2336805 was well tolerated and exhibited rapid, significant antiviral activity after a single dose in HCV-infected subjects. These results support the conduct of further studies evaluating GSK2336805 administered once daily for longer durations in combination with peginterferon, ribavirin, and other direct-acting antivirals. (This study has been registered at ClinicalTrials.gov under registration no. NCT01277692.)

HIV integrase inhibitors such as raltegravir and elvitegravir halt HIV progression, but treatment-emergent resistance and cross-resistance have been observed. The nonnucleoside reverse transcriptase inhibitor etravirine (ETR) may be used in combination with integrase inhibitors in patients with drug resistance. This single-center, open-label, two-period, single-sequence crossover study evaluated the effects of ETR coadministration on the pharmacokinetic profile of S/GSK1265744, an investigational integrase inhibitor in phase 2 studies. Healthy subjects received 30 mg of S/GSK1265744 alone once daily for 10 days (period 1) and in combination with 200 mg of ETR twice daily for 14 days (period 2). Serial plasma samples for pharmacokinetic analyses were collected on day 10 during period 1 and on day 14 during period 2. All treatments were well tolerated. Etravirine had no effects on S/GSK1265744 geometric mean ratios of the area under the curve from time zero until the end of the dosing interval (1.01; 90% confidence interval [CI], 0.956 to 1.06), of the maximum observed plasma concentration (1.04; 90% CI, 0.987 to 1.09), or of the plasma concentration at the end of the dosing interval (0.999; 90% CI, 0.942 to 1.06). Etravirine pharmacokinetics (PK) parameters observed following coadministration with S/GSK1265744 were in the range of historical values reported for ETR alone in healthy subjects. These results indicate that 30 mg of S/GSK1265744 for 10 days as monotherapy followed by an additional 14 days in combination with ETR was well tolerated in healthy subjects and that no dose adjustment of S/GSK1265744 is required when it is coadministered with ETR.

Aims This study aimed to investigate whether cabotegravir (CAB), an integrase inhibitor in development for treatment and prevention of human immunodeficiency virus‐1, influences the pharmacokinetics (PK) of a levonorgestrel (LNG) and ethinyl oestradiol (EO)–containing oral contraceptive (OC) in healthy women. Methods In this open‐label, fixed‐sequence crossover study, healthy female subjects received LNG 0.15 mg/EO 0.03 mg tablet once daily Days 1–10 alone and with oral CAB 30 mg once daily Days 11–21. At the end of each treatment period, subjects underwent predose sampling for concentrations of follicle‐stimulating hormone, luteinizing hormone, and progesterone and serial PK sampling for plasma LNG, EO, and CAB concentrations. Results Twenty women were enrolled, and 19 completed the study. One subject was withdrawn due to an adverse event unrelated to study medications. Geometric least squares mean ratios (90% confidence interval) of LNG + CAB vs. LNG alone for LNG area under the plasma concentration–time curve over the dosing interval of duration τ and maximum observed plasma concentration were 1.12 (1.07–1.18) and 1.05 (0.96–1.15), respectively. Geometric least squares mean ratio (90% confidence interval) of EO + CAB vs. EO alone for EO area under the plasma concentration–time curve over the dosing interval of duration τ and maximum observed plasma concentration were 1.02 (0.97–1.08) and 0.92 (0.83–1.03), respectively. Steady‐state CAB PK parameters were comparable to historical values. There was no apparent difference in mean luteinizing hormone, follicle‐stimulating hormone, and progesterone concentrations between periods. No clinically significant trends in laboratory values, vital signs, or electrocardiography values were observed. Conclusions Repeat doses of oral CAB had no significant effect on LNG/EO PK or pharmacodynamics, which supports CAB coadministration with LNG/EO OCs in clinical practice.

To evaluate the association of efavirenz hypersusceptibility (EFV-HS) with clinical outcome in a double-blind, placebo-controlled, randomized trial of EFV plus indinavir (EFV+IDV) vs. EFV+IDV plus abacavir (ABC) in 283 nucleoside-experienced HIV-infected patients.Rates of virologic failure were similar in the 2 arms at week 16 (p = .509). Treatment discontinuations were more common in the ABC arm (p = .001). Using logistic regression, there was no association between virologic failure and either baseline ABC resistance or regimen sensitivity score. Using 3 different genotypic scoring systems, EFV-HS was significantly associated with reduced virologic failure at week 16, independent of treatment assignment. In some patients on the nucleoside-sparing arm, the nucleoside-resistance mutation L74V was selected for in combination with the uncommonly occurring EFV-resistance mutations K103N+L100I; L74V was not detected as a minority variant, using clonal sequence analysis, when the nucleoside-sparing regimen was initiated.Premature treatment discontinuations in the ABC arm and the presence of EFV-HS HIV variants in this patient population likely made it difficult to detect a benefit of adding ABC to EFV+IDV. In addition, L74V, when combined with K103N+L100I, may confer a selective advantage to the virus that is independent of its effects on nucleoside resistance.

Purpose of review Long-acting cabotegravir may provide a novel therapeutic option for both the treatment and prevention of HIV-1 infection that does not necessitate adherence to a daily regimen. The present review will highlight the unique formulation properties and pharmacologic attributes of long-acting cabotegravir nanosuspension. Recent findings Cabotegravir is a potent integrase strand transfer inhibitor that has been formulated as an oral tablet for daily administration and as a long-acting injectable nanosuspension. Long-acting cabotegravir is readily absorbed following intramuscular and subcutaneous administration and has an elimination half-life of approximately 40 days, allowing for administration on a monthly or less frequent schedule. Repeat-dose pharmacokinetic studies and population pharmacokinetic modeling indicate monthly and bi-monthly dosing achieves clinically relevant plasma concentrations considered effective for HIV maintenance therapy and that quarterly injections are appropriate for investigation as preexposure prophylaxis. Cabotegravir is primarily metabolized by uridine diphosphate glucuronosyltransferase 1A1 and is unlikely to be impacted by the cytochrome P450 metabolic pathway. In vitro and in vivo data suggest cabotegravir has a low propensity to cause, or be subject to, significant drug interactions. Summary The pharmacologic profile of long-acting cabotegravir supports its continued development for both treatment and prevention of HIV-1 infection.

Summary Background In phase 1 trials, the HIV-1 integrase strand transfer inhibitor cabotegravir (GSK1265744) was well tolerated, both alone, and in combination with the non-nucleoside reverse transcriptase inhibitor rilpivirine. We assessed cabotegravir plus rilpivirine, as a two-drug oral antiretroviral regimen, for the maintenance of viral suppression in antiretroviral-naive HIV-1-infected individuals. Methods In the phase 2b Long-Acting antireTroviral Treatment Enabling (LATTE) trial, a multicentre study done in Canada and the USA, antiretroviral-naive HIV-1-infected adults (aged ≥18 years) were randomly allocated in a 1:1:1:1 ratio to oral cabotegravir 10 mg once a day, 30 mg once a day, 60 mg once a day, or oral efavirenz 600 mg once a day with dual nucleoside reverse transcriptase inhibitors (NRTIs) for 24 weeks of induction. Patients who were virologically suppressed by week 24 received a two-drug maintenance regimen consisting of their randomly allocated cabotegravir dose plus oral rilpivirine 25 mg or continued efavirenz plus NRTIs for an additional 72 weeks. Patients and investigators were masked to doses of cabotegravir received for 96 weeks, but not to the assignment of cabotegravir or efavirenz. The primary endpoint was the proportion of patients with fewer than 50 copies per mL of HIV-1 RNA (US Food and Drug Administration snapshot algorithm) at week 48. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, NCT01641809. Findings Of 243 patients randomly allocated and treated, 156 (86%) of 181 patients in the cabotegravir groups (52 [87%] of 60, 51 [85%] of 60, and 53 [87%] of 61 patients in the 10 mg, 30 mg, and 60 mg groups, respectively) and 46 (74%) of 62 in the efavirenz group had fewer than 50 copies per mL of HIV-1 RNA after induction therapy. After patients in the cabotegravir groups were changed over from dual NRTIs to rilpivirine at week 24, 149 (82%; 95% CI 77–88) patients in the cabotegravir groups (48 [80%; 70–90], 48 [80%; 70–90], and 53 [87%; 78–95] patients in the 10 mg, 30 mg, and 60 mg groups, respectively) versus 44 (71%; 60–82) in the efavirenz group were virologically suppressed at week 48, and 137 (76%; 69–82) receiving cabotegravir (41 [68%; 57–80], 45 [75%; 64–86], and 51 [84%; 74–93] patients in the 10 mg, 30 mg, and 60 mg groups, respectively) versus 39 (63%; 51–75) in the efavirenz group were virologically suppressed at week 96. Treatment-related adverse events were reported by 93 (51%) cabotegravir-treated patients (28 [47%], 32 [53%], and 33 [54%] patients in the 10 mg, 30 mg, and 60 mg groups, respectively) and 42 (68%) efavirenz-treated patients. Six (3%) patients in the cabotegravir groups (one [2%], one [2%], and four [7%] patients in the 10 mg, 30 mg, and 60 mg groups, respectively) withdrew because of treatment-emergent adverse events compared with nine (15%) in the efavirenz group. Interpretation Cabotegravir plus dual NRTI therapy had potent antiviral activity during the induction phase. As a two-drug maintenance therapy, cabotegravir plus rilpivirine provided antiviral activity similar to efavirenz plus dual NRTIs until the end of week 96. Combined efficacy and safety results lend support to our selection of oral cabotegravir 30 mg once a day for further assessment. LATTE precedes studies of the assessment of longacting injectable formulations of both drugs as a two-drug regimen for the treatment of HIV-1 infection. Funding ViiV Healthcare and Janssen Research and Development.

GSK2336805 is a hepatitis C virus NS5A inhibitor in clinical development for the treatment of chronic hepatitis C virus infection. This was a single-center, randomized, double-blind, placebo-controlled, two-period crossover study in healthy adults to evaluate the effects of a single 150-mg dose of GSK2336805 on echocardiographic measures of contractility. GSK2336805 had no effect on ejection fraction, and there was no significant correlation between GSK2336805 plasma concentration and ejection fraction. (This study has been registered at Clinicaltrials.gov under registration no. NCT01424540.)

Abacavir is an effective antiretroviral drug used to treat HIV-1 infection. Approximately 5% of patients treated with abacavir develop a hypersensitivity reaction that requires discontinuation of the drug. In an initial pharmacogenetic study conducted in a predominantly White male population, multiple markers in the human leukocyte antigen (HLA)-B chromosomal region were associated with hypersensitivity to abacavir. The HLA-B*5701 association has now been confirmed in White males in a subsequent, larger study (n=293, p=4.7 x 10(-18)) and is also observed in White females (n=56, p=6.8 x 10(-6)) and Hispanics (n=104, p=2.1 x 10(-4)). HLA-B*5701 was not associated with hypersensitivity in Blacks (n=78, p=0.27). HLA-B*5701 alone lacks sufficient predictive value to identify patients at risk for hypersensitivity to abacavir across diverse patient populations. Efforts are ongoing to identify markers with sufficient sensitivity and specificity to be clinically useful. Even after a marker set is identified, appropriate clinical identification and management of hypersensitivity to abacavir must remain the cornerstone of clinical practice.

Objective Pharmacokinetics, safety, and tolerability of GSK1265744 (744) and rilpivirine (RPV) (TMC278) were assessed after repeat dosing of long-acting (LA) injectable formulations in healthy subjects. Methods Subjects received a 14-day lead-in of oral 744 (30 mg/d) to assess safety and tolerability before injectable administration. Subjects were randomized into 4 cohorts: 800 mg of 744 LA intramuscularly (IM) followed by 3 monthly doses of (1) 200 mg subcutaneously, (2) 200 mg IM, (3) 400 mg IM, or (4) a second injection of 800 mg IM after 12 weeks. Cohorts 2 and 3 also received IM doses of RPV LA at months 3 (1200 mg) and 4 (900 or 600 mg). Pharmacokinetics and safety were assessed throughout the trial. Results Forty-seven subjects enrolled; 40 received ≥1 LA injection with 37 completing all planned injections. Seven subjects discontinued 744 oral (non-drug-related, n = 6; dizziness, n = 1). The 744 LA and RPV LA injections were generally well tolerated, with grade 1 injection site reactions most commonly reported. Three subjects discontinued during injection phase (consent withdrawn, n = 2; self-limited rash, n = 1). There were no grade 3 or 4 adverse events and no clinically significant trends in laboratory abnormalities, electrocardiograms, or vital signs. All dose cohorts achieved therapeutically relevant plasma concentrations of each drug within 3 days with prolonged exposure over the dosing interval. Plasma concentrations of 744 exceeded the protein-adjusted IC90 and RPV plasma concentrations and were comparable to steady-state oral RPV 25 mg/d. Conclusions These data support the potential application of dual-therapy 744 LA and RPV LA for treatment of HIV-1 infection.

Keeping HIV at Bay? Preexposure prophylaxis involving daily doses of drugs can, with variable success rates, interrupt HIV transmission for individuals at high risk of acquiring HIV infection. However, one reason for the variability seen in the response to such drugs is a lack of adherence to the prescribed regimen. Andrews et al. (p. 1151 ) formulated a potent integrase inhibitor as a long-acting agent that protected macaques from repeated intrarectal challenges of simian HIV. Decay of plasma levels of drug were associated with increased susceptibility to infection after virus exposure. The drug levels required for a high degree of protection could potentially be achieved with quarterly injections in humans.

OBJECTIVE: To characterize early and later indices of cellular restoration among HIV-1 infected persons treated with abacavir and one protease inhibitor and to identify predictors of CD4 cell increases. METHODS: Flow-cytometric analyses of lymphocyte phenotypes among 71 antiretroviral treatment naive adults in a 48 week treatment trial. RESULTS: During the first 4 weeks of therapy, increases in naive and memory CD4 cells and in B cells were seen; naive CD8 cells increased while CD8 cells remained stable as memory CD8 cells decreased. During the second phase total CD4 and naive CD4 and CD8 cells increased while total CD8 and memory CD8 cells decreased. The numbers of CD4 cells that expressed CD28 increased from a median of 308 x 10(6)/l at baseline to 477 x 10(6)/l at week 48. Higher baseline plasma HIV-1 RNA levels predicted the magnitude of early CD4 (r = 0.35; P = 0.01), memory CD4 (r = 0.38; P = 0.001) and CD28 CD4 cell (r = 0.29; P = 0.01) restoration but was not related to second phase changes. Younger age predicted a greater second phase (but not first phase) increase in naive CD4 cells (r = -0.31; P = 0.03). CONCLUSIONS: Higher baseline levels of HIV-1 replication determine the magnitude of first phase CD4 cell increases after suppression of HIV-1 replication. Second phase (primarily naive) CD4 cell increases are not related to HIV-1 replication but are inversely relate to age suggesting that thymic potential is a major determinant of long term cellular restoration in HIV-1 infected persons receiving antiretroviral therapy.

Objective To assess antiretroviral efficacy and safety of abacavir in combination with selected HIV-1 protease inhibitors. Design A 48-week, open-label study. Materials and Methods Eighty-two antiretroviral naive HIV-1-infected adults (CD4 cell count ≥100 cells/mm3, plasma HIV-1 RNA ≥5000 copies/ml) were randomly assigned to receive abacavir (300 mg twice daily) in combination with standard doses of one of five protease inhibitors: indinavir, saquinavir soft-gel, ritonavir, nelfinavir or amprenavir. Adults who met protocol-defined switch criteria at or after week 8 could modify their randomized therapy. Antiretroviral activity was assessed by the proportion of subjects with plasma HIV-1 RNA ≤400 and ≤50 copies/ml, and by changes in plasma HIV-1 RNA levels and CD4 cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities. Results At week 48, the proportion of subjects in the indinavir, saquinavir, ritonavir, nelfinavir and amprenavir groups with plasma HIV-1 RNA ≤400 copies/ml was 53, 50, 50, 41 and 56%, respectively, and the proportion with HIV-1 RNA ≤50 copies/ml was 47, 56, 50, 47, and 44%, respectively (by intent-to-treat analysis). Median reductions from baseline in plasma HIV-1 RNA for each group ranged from 1.7 to 2.4 log10 copies/ml. The median CD4 cell count increase from baseline was 195, 131, 116, 136 and 259 cells/mm3 in the indinavir, saquinavir, ritonavir, nelfinavir, and amprenavir groups, respectively. Overall, the most common adverse events attributed to study drugs were diarrhoea, nausea, malaise/fatigue, headache and perioral paresthesia. The frequency of treatment-limiting adverse events did not differ between groups. Conclusions: Abacavir is safe and effective when used in combination with a protease inhibitor.

GSK1265744 is an HIV integrase strand transfer inhibitor selected for clinical development.This first-time-in-human and phase IIa investigation assessed GSK1265744 antiviral activity, pharmacokinetics, safety, and tolerability in healthy and HIV-1-infected subjects.This double-blind, placebo-controlled study consisted of a dose escalation of single (part A) and multiple (part B) oral doses in 48 healthy subjects and an oral dose (part C) in 11 HIV-1-infected subjects. In part A, 2 cohorts of 9 subjects received either 5 and 25 mg or 10 and 50 mg. In part B, 3 cohorts of 10 subjects received 5, 10, or 25 mg once daily for 14 days. In part C and the phase IIa study, subjects received 5 or 30 mg once daily for 10 days.Dose-proportional increases in drug exposure were observed in healthy and HIV-1-infected subjects. In healthy subjects, pharmacokinetic variability was low following single or repeat dosing (coefficient of variation, 13%-34% and 15%-23%, respectively). Mean plasma half-life was 31.5 hours. GSK1265744 monotherapy significantly reduced plasma HIV-1 RNA from baseline to day 11 in HIV-1-infected subjects receiving 5 or 30 mg versus placebo (P.001); mean decrease was 2.2 to 2.3 log10 copies/mL, respectively. Study drug was generally well tolerated with no clinically relevant trends in laboratory values, vital signs, or electrocardiograms.GSK1265744 was well tolerated in healthy and HIV-1-infected subjects. Results demonstrate once-daily doses of 5 or 30 mg exceeded minimum target therapeutic concentrations and produced a significant reduction in plasma HIV-1 RNA viral load.

Purpose of review Long-acting antiretroviral (ARV) drugs may improve adherence to therapy and extend opportunities for therapeutic or prophylactic intervention to underserved patient populations. This review focuses on recent advances in the development of small molecule long-acting injectable ARV agents. Recent findings The need for combination ART and physicochemical and dosing limitations of current ARV drugs impede attempts to redevelop them as long-acting injectable formulations. However, the intrinsic properties of rilpivirine, a nonnucleoside reverse transcriptase inhibitor, and GSK1265744, an HIV-1 integrase strand transfer inhibitor, have enabled crystalline nanoparticle formulations to progress to clinical trials. Summary Investigational long-acting injectable nanoformulations of rilpivirine and GSK1265744 are clinical-stage development candidates. Complementary pharmacologic properties of both agents – different mechanisms of action, resistance profiles, metabolic pathways, lack of drug interactions and low daily oral doses – offer the potential for combination use. Phase I studies of the pharmacokinetics and safety of each long-acting formulation alone and in combination indicate that a monthly dosing regimen is possible for HIV treatment. An ongoing phase IIb trial of oral GSK1265744 and oral rilpivirine is evaluating this two-drug regimen for maintenance of virologic suppression; results will inform future studies using the injectable formulations. Additional preclinical and clinical studies indicate a potential use of each agent for HIV pre-exposure prophylaxis.

Maximizing the durability of viral suppression is a key goal of antiretroviral therapy. The objective of AIDS Clinical Trials Group Study 372A was to determine whether the intensification strategy of adding abacavir to an effective indinavir-dual nucleoside regimen would delay the time to virologic failure.Zidovudine-experienced subjects (n=229) on therapy with indinavir + zidovudine + lamivudine with plasma HIV-1 RNA levels500 copies/mL were randomized to abacavir 300 mg twice daily or placebo. The primary endpoint was the time to treatment failure, defined as a composite of confirmed virologic failure (2 consecutive HIV-1 RNAs200 copies/mL) and treatment discontinuation.At baseline, the study population was 88% male with a median age of 41 years and median CD4 cell count of 250/mm3. Median follow-up was 4.4 years. The primary endpoint was reached in 61/116 of abacavir versus 62/113 of placebo recipients (P=.77); virologic failure occurred in 34/116 and 42/113 patients, respectively (P=.22). There were no differences in the proportions of subjects with plasma HIV-1 RNA levels below 50 copies/mL, in CD4 cell count increases, nor adverse events between the arms. In the study, 17% of subjects developed nephrolithiasis, 2% experienced abacavir hypersensitivity, and 4.8% experienced at least 1 serious cardiovascular event (7 [6%] in the abacavir arm, 4 [3.5%] in the placebo arm). In additional secondary and post hoc analyses, rates of intermittent viremia, suppression below a plasma HIV-1 RNA level of 6 copies/mL, and HIV-1 proviral DNA levels in peripheral blood mononuclear cells were not significantly different in the 2 arms.The strategy of intensification with abacavir in patients who are virologically suppressed on a stable antiretroviral regimen does not confer a clinical or virologic benefit. As antiretroviral regimens have become more potent since this trial was completed, it will be even more difficult to prove that late intensification of already virologically suppressed patients will add benefit. However, studies are warranted with drugs with new mechanisms of action to determine whether the level of persistent viremia below 50 copies/ mL can be further reduced and what influence this may have on latent HIV reservoirs.

The hypersensitivity (HSR) to abacavir (ABC) pharmacogenetics (PGx) program represents the progression from an exploratory discovery to a validated biomarker. Within the program, two retrospective PGx studies were conducted to identify HIV-1 patients at increased risk for ABC HSR, a treatment-limiting and potentially life-threatening adverse event. A strong statistical association between the major histocompatibility complex allele, HLA-B*5701, and clinically diagnosed ABC HSR was identified but varied between racial populations. Subsequently, ABC skin patch testing was introduced as a research tool to supplement clinical case ascertainment. In a randomized, prospective study evaluating the clinical utility of HLA-B*5701 screening, avoidance of ABC in HLA-B*5701-positive patients significantly reduced clinically diagnosed ABC HSR and eliminated patch test-positive ABC HSR. Finally, a retrospective PGx study supports the generalizability of the association across races. Prospective HLA-B*5701 screening should greatly reduce the incidence of ABC HSR by identifying patients at high risk for ABC HSR before they are treated.

Pharmacogenetics (PGx) - the study of DNA variation in the human genome and the way this impacts the efficacy and safety of medicines - is becoming an increasingly important research tool as physicians, patients, regulatory authorities and payers look for innovative ways to improve the risk:benefit ratio of medicines. While scientific knowledge about PGx is rapidly increasing, implementation of PGx findings to patient care has yet to be fully achieved. One area where significant progress has been made is in the identification of PGx markers associated with variable response to antiretroviral medicines. For example, the major histocompatibility complex HLA-B*5701 allele has been associated with hypersensitivity to abacavir (ABC) by several independent researchers. While PGx associations have been identified largely through retrospective examination, the clinical utility of these PGx markers in patient care has not been prospectively determined in a randomized study. This paper outlines the design of a study to evaluate the utility of prospective screening for HLA-B*5701 to reduce the incidence of ABC hypersensitivity in an ABC-naive population of HIV-infected subjects. This represents the first fully powered, randomized, blinded, prospective study to determine the clinical utility of PGx screening to reduce drug-associated adverse events in any patient population. This type of trial design may have utility for other important medicines which have treatment-limiting side effects.

The objective of pharmacogenetic research is to identify a genetic marker, or a set of genetic markers, that can predict how a given person will respond to a given medicine. To search for such marker combinations that are predictive of adverse drug events, we have developed and applied two complementary methods to a pharmacogenetic study of the hypersensitivity reaction (HSR) associated with treatment with abacavir, a medicine that is used to treat HIV-infected patients. Our results show that both of these methods can be used to uncover potentially useful predictive marker combinations. The pairwise marker combination method yielded a collection of marker pairs that featured a spectrum of sensitivities and specificities. Recursive partitioning results led to the genetic delineation of multiple risk categories, including those with extremely high and extremely low risk of HSR. These methods can be readily applied in pharmacogenetic candidate gene studies as well as in genome-wide scans.

ObjectiveTo evaluate HIV-1 reverse transcriptase genotypic and phenotypic indicators of resistance to abacavir (ABC) as predictors of ABC antiviral efficacy.DesignThe study was a retrospective, combined analysis of five multicentre trials in which ABC was added as a single agent to background antiretroviral therapy in experienced adults.MethodsBaseline HIV-1 genotype and phenotypic susceptibility to ABC were determined and the association of genotype and phenotype with virological response after addition of ABC was analysed.ResultsOverall, 68% of these therapy-experienced subjects had a virological response (>0.5 log10or ConclusionsVirological response to ABC may be diminished significantly by multiple NRTI-associated mutations and/or by reductions in phenotypic susceptibility to ABC. However, many subjects with baseline samples showing evidence of resistance to NRTIs respond to ABC.