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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.

Pre-exposure prophylaxis (PrEP) has demonstrated remarkable effectiveness protecting at-risk individuals from HIV-1 infection. Despite this record of effectiveness, concerns persist about the diminished protective effect observed in women compared with men and the influence of adherence and risk behaviors on effectiveness in targeted subpopulations. Furthermore, the high prophylactic efficacy of the first PrEP agent, tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), presents challenges for demonstrating the efficacy of new candidates. Trials of new agents would typically require use of non-inferiority (NI) designs in which acceptable efficacy for an experimental agent is determined using pre-defined margins based on the efficacy of the proven active comparator (i.e. TDF/FTC) in placebo-controlled trials. Setting NI margins is a critical step in designing registrational studies. Under- or over-estimation of the margin can call into question the utility of the study in the registration package. The dependence on previous placebo-controlled trials introduces the same issues as external/historical controls. These issues will need to be addressed using trial design features such as re-estimated NI margins, enrichment strategies, run-in periods, crossover between study arms, and adaptive re-estimation of sample sizes. These measures and other innovations can help to ensure that new PrEP agents are made available to the public using stringent standards of evidence.

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.

Background Cabotegravir (CAB), an INI, is under development in both oral and long-acting (LA) injectable formulations. LATTE (NCT01641809) was designed to select a daily oral dose of CAB and evaluate a two-drug ART regimen with rilpivirine (RPV), as suppressive maintenance therapy. Results enabled the LATTE-2 (NCT02120352) study to evaluate CAB LA + RPV LA dosed once every 1 or 2 months. Methods Phase 2b, multicentre, partially blinded dose-ranging study in ART-naïve HIV infected adults, randomized 1:1:1:1 to the induction regimen of once-daily oral CAB 10, 30, or 60 mg or efavirenz (EFV) 600 mg with TDF/FTC or ABC/3TC through W24. CAB patients with VL Results A total of 243 patients were randomized and initiated treatment (ITT-E). Of those randomized to CAB (n = 181), 160 patients began CAB + RPV (W24) and 138 continued into OL phase (W96). One hundred and ten patients successfully completed the study (W312). Among patients who began CAB + RPV at W24, 66% maintained Conclusion As maintenance therapy in virologically suppressed patients, the 2DR CAB + RPV provided durable viral suppression through W312. Through 7 years of study, CAB + RPV continues to be generally safe and well tolerated. Disclosures All Authors: No reported Disclosures.

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.

Background Fosdevirine (GSK2248761) is a non-nucleoside reverse transcriptase inhibitor with HIV-1 activity against common efavirenz-resistant strains. Two partially blind, randomized, Phase IIb studies were initiated (1 in treatment-naive and 1 in treatment-experienced subjects with HIV) to select a once-daily dose of fosdevirine for Phase III trials. Methods In the SIGNET study, treatment-naive subjects were randomized 1:1:1 to receive once-daily fosdevirine 100 or 200 mg or efavirenz 600 mg, each along with tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg or abacavir/lamivudine 600 mg/300 mg. In the SONNET study, treatment-experienced subjects with non-nucleoside reverse transcriptase inhibitor-resistant HIV-1 were randomized 1:1:1 to treatment with fosdevirine 100 or 200 mg once daily or etravirine 200 mg twice daily, each along with twice-daily darunavir/ritonavir 600/100 mg and raltegravir 400 mg. The primary efficacy end point was the proportion of subjects with HIV-1 RNAResults A total of 35 subjects were exposed to fosdevirine 100 or 200 mg. Trials were halted when 5 treatment-experienced subjects (1 receiving fosdevirine 100 mg, 4 receiving fosdevirine 200 mg) developed new-onset seizures after ≥4 weeks of exposure to fosdevirine. There was no clear association between seizures and fosdevirine plasma drug levels. Time to seizure onset ranged from 28 to 81 days, and all 5 subjects experienced ≥1 seizure after drug discontinuation. Conclusions The delayed onset of seizures after fos-devirine exposure and persistence after discontinuation is without precedent in antiretroviral drug development, leading to additional investigation and underscoring the need for careful subject monitoring.

Background. Although the human leukocyte antigen (HLA)–B*5701 is highly associated with a hypersensitivity reaction (HSR) to abacavir (ABC), variable sensitivities have been reported when clinical data alone have been used to define an ABC HSR. This study evaluated the sensitivity of detection of the HLA-B*5701 allele as a marker of ABC HSRs in both white and black patients, using skin patch testing to supplement clinical diagnosis. Methods. White and black patients, identified through chart review, were classified as having received a diagnosis of an ABC HSR based on clinical findings only (a clinically suspected ABC HSR) or based on clinical findings and a positive skin patch test result (an immunologically confirmed [IC] ABC HSR). Control subjects were racially matched subjects who tolerated ABC for 12 weeks without experiencing an ABC HSR. Patients and control subjects were tested for the presence of HLA-B*5701. Sensitivity, specificity, and odds ratios for the detection of HLA-B*5701 as a marker for an ABC HSR were calculated for white and black participants. Results. Forty-two (32.3%) of 130 white patients and 5 (7.2%) of 69 black patients who met the criteria for clinically suspected HSRs had IC HSRs. All 42 white patients with IC HSRs were HLA-B*5701 positive (sensitivity, 100%; odds ratio, 1945; 95% confidence interval, 110–34,352). Among all white patients with clinically suspected HSRs, sensitivity was 44% (57 of 130 patients tested positive for HLA-B*5701); specificity among white control subjects was 96%. Five of 5 black patients with IC HSRs were HLA-B*5701 positive (sensitivity, 100%; odds ratio, 900; 95% confidence interval, 38–21,045). Among black patients with clinically suspected HSRs, the sensitivity was 14% (10 of 69 tested positive for HLA-B*5701); specificity among black control subjects was 99%. Conclusions. Although IC ABC HSRs are uncommon in black persons, the 100% sensitivity of HLA-B*5701 as a marker for IC ABC HSRs in both US white and black patients suggests similar implications of the association between HLA-B*5701 positivity and risk of ABC HSRs in both races.

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.

Background & Aims Farglitazar (GI262570), an insulin-sensitizing agent, selectively binds and activates peroxisome proliferator-activated receptor γ (PPARγ) and inhibits stellate cell activation. We evaluated its antifibrotic effect in patients with chronic hepatitis C that did not respond to standard-of-care therapy. Methods Patients with fibrosis of Ishak stages 2–4 (n = 265), based on analysis of liver biopsy samples, were randomly assigned to groups given once-daily doses of 0.5 mg farglitazar, 1.0 mg farglitazar, or placebo for 52 weeks; repeat liver biopsy samples were then obtained. The primary end points were changes in levels of α-smooth muscle actin (SMA) expression and collagen, based on morphometry and ranked histologic assessments. Results Two hundred nine patients had paired biopsy specimens adequate for analysis (81.5% with pretreatment Ishak scores of stage 2 or 3). There was no overall difference in SMA ( P = .58) or collagen ( P = .99) levels at week 52. SMA levels increased by a median of 49% in samples from patients given placebo, 58% in patients given 0.5 mg farglitizar and 52% in patients given 1.0 mg farglitizar, respectively. Collagen increased by 27% in placebo samples and 31% in samples from patients given either dose of farglitizar. There were no significant differences between treatment groups in the ranked assessment of paired biopsy specimens or in the proportion of patients with a change in fibrosis score ≥ Ishak stage. Conclusions In patients with chronic hepatitis C and moderate fibrosis, 52 weeks of treatment with farglitazar does not affect stellate cell activation or fibrosis (measured by morphometry or comparison of paired biopsy specimens).