Long-acting cabotegravir and rilpivirine dosed every 2 months in adults with HIV-1 infection (ATLAS-2M), 48-week results: a randomised, multicentre, open-label, phase 3b, non-inferiority study

BACKGROUND

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.

METHODS

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.

FINDINGS

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.

INTERPRETATION

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.

FUNDING

ViiV Healthcare and Janssen.

833. Efficacy and Safety of Long-Acting Cabotegravir + Rilpivirine in Participants with HIV/HCV Co-infection: ATLAS-2M 48-Week Results

Background

The phase IIIb ATLAS-2M study demonstrated non-inferiority of long-acting (LA) cabotegravir (CAB) + rilpivirine (RPV) dosed every 8 weeks (Q8W) compared with every 4 weeks (Q4W) for maintenance of virologic suppression. Hepatitis C virus (HCV) co-infection occurs in ~6% of people with HIV due to shared modes of transmission. We report efficacy and safety of CAB + RPV LA in participants with HIV/HCV co-infection in ATLAS-2M.

Methods

Participants with HIV-1 RNA &lt; 50 c/mL receiving CAB + RPV LA Q4W (transitioned from ATLAS [NCT02951052]) or oral comparator ART were randomized 1:1 to receive CAB + RPV LA Q4W or Q8W. Baseline HCV RNA was assessed by polymerase chain reaction. Participants with symptomatic chronic HCV infection requiring treatment within 12 months or liver enzymes not meeting entry criteria were excluded. Week 48 assessments included proportion with HIV-1 RNA ≥50 and &lt; 50 c/mL (Snapshot algorithm), general and hepatic safety, and pharmacokinetics.

Results

HIV/HCV co-infection was present in 10 (1%) of 1045 participants, 60% of whom were female at birth. At Week 48, 9/10 (90%) and 972/1035 (94%) participants with HIV/HCV co-infection and HIV mono-infection, respectively, had HIV-1 RNA &lt; 50 c/mL (adjusted difference, 4.1; 95% CI, −14.5 to 22.6). No participants with HIV/HCV co-infection had HIV-1 RNA ≥50 c/mL (vs 14/1035 [1%] with HIV mono-infection) or confirmed virologic failure through Week 48 (vs 10 [1%] with HIV mono-infection); 1/10 (10%) discontinued for reasons other than adverse events (AEs). Excluding injection site reactions (ISRs), AEs and serious AEs were reported in 4 (40%) and 0 participants with HIV/HCV co-infection, respectively; the only AE reported in &gt;1 participant was injection site pain (n=5; 50%). In participants with HIV/HCV co-infection, all ISRs were grade 1/2; none led to withdrawal. No hepatic laboratory abnormalities were reported in participants with HIV/HCV co-infection through Week 48; rates were low in those with HIV mono-infection (Table). Plasma CAB and RPV concentrations were similar between groups.

Conclusion

CAB + RPV LA was effective and well tolerated in this small cohort of participants with HIV and asymptomatic HCV co-infection.

Disclosures

Ronald D’Amico, DO, MSc, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Paul Benn, MB ChB FRCP, ViiV Healthcare (Employee) Shanker Thiagarajah, MB ChB, GlaxoSmithKline (Employee, Shareholder) Susan L. Ford, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Eileen Birmingham, MD, MPH, Janssen Research and Development (Employee, Shareholder) Ojesh R. Upadhyay, MPH, MBA, GlaxoSmithKline (Employee) Louise Garside, PhD, GlaxoSmithKline (Employee) Rodica Van Solingen-Ristea, MD, Janssen Research and Development (Employee)ViiV Healthcare (Employee) Kati Vandermeulen, M.SC., Janssen Research and Development (Employee) William Spreen, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee)

877. North American Phase 3/3b Experience with Long-Acting Cabotegravir and Rilpivirine: Efficacy, Safety, and Virologic Outcomes

Background

Cabotegravir (CAB) plus rilpivirine (RPV) is the first complete long-acting (LA) regimen recommended by treatment guidelines for the maintenance of HIV-1 virologic suppression. CAB+RPV LA dosed every 4 weeks (Q4W) or every 8 weeks (Q8W) demonstrated noninferior efficacy in multinational Phase 3/3b trials. This post hoc descriptive analysis summarizes efficacy, virologic outcomes, safety, and treatment preference for US and Canadian (CAN) participants through Week (W) 48.

Methods

This analysis focuses on data for US/CAN participants naive to CAB+RPV (n=376) from the larger pooled population of the ATLAS, FLAIR, and ATLAS-2M Phase 3/3b studies (N=1245). Endpoints included the proportion of participants with plasma HIV-1 RNA ≥ 50 and &lt; 50 c/mL at W48 (FDA Snapshot algorithm), incidence of confirmed virologic failure (CVF; 2 consecutive HIV-1 RNA ≥ 200 c/mL), safety, and treatment preference through W48.

Results

376 US/CAN participants received CAB+RPV LA Q4W or Q8W. Median (range) age was 39y (20–74); 14.9% were female, 66.0% were White. At W48, 93.1% (350/376) maintained virologic suppression (HIV-1 RNA &lt; 50 c/mL), 1.9% (7/376) had HIV-1 RNA ≥ 50 c/mL, and 0.8% (3/376) met the CVF criterion, consistent with the overall global pooled population (Table 1). Two of the three participants with CVF had ≥ 2 of the three baseline factors (archived RPV resistance-associated mutations [RAMs], HIV subtype A6/A1, body mass index [BMI] ≥ 30 kg/m2) previously associated with CVF. Among the US/CAN participants with a single baseline factor, none met CVF. Overall, archived RPV RAMs were observed in 3.2% (12/376), HIV subtype A6/A1 in 1.1% (4/376), and BMI ≥ 30 kg/m2 in 26.3% (99/376) of participants. Safety and injection site reaction findings were similar to the overall pooled population (Table 2). Most participants (120/134, 89.6%) preferred LA over oral dosing (7/134, 5.2%).

Table 1. Snapshot outcomes following CAB+RPV LA Q4W and Q8W at Week 48 in participants naive to CAB+RPV from ATLAS, FLAIR, and ATLAS-2M (ITT-E population)

Conclusion

In US/CAN Phase 3/3b trial participants, CAB+RPV LA was highly effective and well tolerated, with outcomes consistent with the overall pooled population. Baseline prevalence of archived RPV RAMs and subtype A6/A1 was low and aligned with regional prevalence/surveillance data. CAB+RPV LA provides a tolerable and effective injectable LA treatment option for virologically suppressed US/CAN individuals with HIV.

Disclosures

Babafemi O. Taiwo, MBBS, Gilead (Consultant)Merck (Consultant)ViiV Healthcare (Consultant) Darrell Tan, MD PhD, Abbvie (Grant/Research Support)Gilead (Grant/Research Support)GlaxoSmithKline (Scientific Research Study Investigator)ViiV Healthcare (Grant/Research Support) Parul Patel, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Paula Teichner, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Joseph Polli, PhD, FAAPS, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Louise Garside, PhD, GlaxoSmithKline (Employee) Ronald D’Amico, DO, MSc, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Christine L. Talarico, M.S., GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Rodica Van Solingen-Ristea, MD, Janssen Research and Development (Employee)ViiV Healthcare (Employee) Bryan Baugh, MD, Janssen, Johnson & Johnson (Employee, Shareholder) William Spreen, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Michael Aboud, MBChB, MRCP, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Matthew Bosse, DO, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee)

885. Pregnancy Outcomes and Pharmacokinetics in Pregnant Women Living with HIV Exposed to Long-Acting Cabotegravir and Rilpivirine in Clinical Trials

Background

Limited data exist among women living with HIV who become pregnant while exposed to long-acting (LA) cabotegravir (CAB) and rilpivirine (RPV). We report outcomes in pregnant participants and LA pharmacokinetic (PK) tail data in pregnant women exposed to CAB+RPV with live births.

Methods

Women of reproductive potential exposed to ≥ 1 dose of CAB+RPV (oral/LA) from ViiV-sponsored Phase 2/3/3b clinical treatment studies and the compassionate use program were included in this analysis and pregnancies identified. Per protocol, upon identification of pregnancy, CAB+RPV was discontinued and an alternative regimen initiated, with continued quarterly PK sampling for 52 weeks post last injection during long-term safety follow-up (LTFU). Descriptive characteristics of pregnant women and birth outcomes and available CAB and RPV PK during pregnancy for those with live births are summarized.

Results

As of March 31, 2021, 26/325 women of reproductive potential (age 18–49 years) became pregnant while exposed to CAB+RPV (5 oral, 21 LA [including 3 following LA discontinuation]). There were 11 live births (1 oral, 10 LA), of which 10 had no reported congenital abnormalities and 1 had reported congenital ptosis, in a pre-term infant with intrauterine growth restriction. There were 9 elective terminations and 6 miscarriages (5 in first 9 weeks of gestation). Ten women exposed to intramuscular CAB+RPV LA became pregnant with subsequent live birth outcomes, including 3 infants conceived during the PK tail in LTFU. All women were virologically suppressed at time of pregnancy identification. In women becoming pregnant on LA dosing, plasma CAB and RPV concentrations during pregnancy were within the range of expected concentrations in non-pregnant women. Two of 10 women with live births exposed to CAB+RPV LA continued LA therapy during pregnancy (compassionate use program participants).

Conclusion

Pregnancy outcomes in women exposed to CAB+RPV at conception are consistent with earlier findings. There was 1 reported congenital anomaly among 11 live births. CAB and RPV PK tail in pregnancy was within the expected range for non-pregnant women. Ongoing monitoring of birth defects within the antiretroviral pregnancy registry and pregnancy surveillance within the treatment program continues.

Disclosures

Parul Patel, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Susan L. Ford, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Mark Baker, PhD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Claudia Meyer, MBChB, MRCP, MSc, FRCPath, DTM&H, GlaxoSmithKline (Employee, Shareholder) Louise Garside, PhD, GlaxoSmithKline (Employee) Ronald D’Amico, DO, MSc, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Rodica Van Solingen-Ristea, MD, Janssen Research and Development (Employee)ViiV Healthcare (Employee) Herta Crauwels, PhD, Janssen (Employee) Joseph Polli, PhD, FAAPS, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Ciara Seal, BS, GlaxoSmithKline (Employee, Shareholder) Shanker Thiagarajah, MB ChB, GlaxoSmithKline (Employee, Shareholder) Eileen Birmingham, MD, MPH, Janssen Research and Development (Employee, Shareholder) William Spreen, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Bryan Baugh, MD, Janssen, Johnson & Johnson (Employee, Shareholder) Matthew Bosse, DO, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Vani Vannappagari, MBBS, MPH, PhD, ViiV Healthcare Limited (Employee)

Cabotegravir for HIV Prevention in Cisgender Men and Transgender Women

BACKGROUND

Safe 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.

METHODS

We 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.

RESULTS

The 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.

CONCLUSIONS

CAB-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.).

Multiparametric magnetic resonance imaging to characterize cabotegravir long-acting formulation depot kinetics in healthy adult volunteers

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 (C_max ) 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, C_max 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 C_max and partial AUC independently of anatomical distribution.

Multicompartmental pharmacokinetic evaluation of long-acting cabotegravir in healthy adults for HIV preexposure prophylaxis

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.

1035. Patient-Reported Outcomes on Long-Acting Cabotegravir + Rilpivirine as Maintenance Therapy: FLAIR 96-Week Results

Background

In the phase 3 FLAIR study, switching to monthly injectable long-acting (LA) cabotegravir (CAB) + rilpivirine (RPV) was noninferior to continued daily oral dolutegravir/abacavir/lamivudine (DTG/ABC/3TC) for the maintenance of virologic suppression over 96 weeks in adults with HIV-1. Key patient-reported outcomes (PROs) through Week 96 are presented.

Methods

In FLAIR, ART-naive adult participants received induction therapy with oral DTG/ABC/3TC for 20 weeks. Those with HIV-1 RNA < 50 c/mL at 16 weeks were randomized (1:1) to continue DTG/ABC/3TC or receive monthly CAB + RPV LA injections after a 4-week lead-in with daily oral CAB + RPV through Week 96. Treatment satisfaction (HIV Treatment Satisfaction Questionnaire status version [HIVTSQs]) and acceptability of injections (Perception of Injection [PIN] Questionnaire) up to Week 96 were secondary endpoints.

Results

A total of 566 participants were randomized (median age, 34 years; 22% female); baseline characteristics were similar between treatment groups. At Week 96, significantly greater improvement from baseline in total treatment satisfaction score was observed in the CAB + RPV LA vs DTG/ABC/3TC treatment group (adjusted mean difference, 2.3 [95% CI, 1.1-3.5]; P< 0.001), further increasing from Weeks 24 (2.1 [0.9-3.3]) and 44 (0.7 [−0.4, 1.9]). Key drivers for the difference in HIVTSQs between treatment groups were items assessing convenience, flexibility, and satisfaction to continue with LA therapy. In participants receiving CAB + RPV LA, mean score for the “Acceptability of ISRs” dimension of PIN (scale, 1-5) significantly decreased (improved) from Week 5 to Weeks 41, 48, and 96 (2.08 to 1.71, 1.66, and 1.71, respectively; P< 0.001 for all). In addition, 82% and 85% of LA participants, respectively, rated pain and local reactions due to injections as “totally” or “very acceptable” at Week 96.

Conclusion

At Week 96, FLAIR participants receiving LA therapy reported greater improvement in treatment satisfaction compared with participants continuing on daily oral medication as well as overall good acceptability of injections with improvement over time. Overall, these results support monthly CAB + RPV LA as an alternative to daily oral regimens for adults with HIV-1.

Disclosures

Vasiliki Chounta, MSc, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Sharon Walmsley, FRCPC, MD, MSC, GSK (Grant/Research Support)ViiV Healthcare (Grant/Research Support) David Dorey, MMATH, GlaxoSmithKline Inc. (Employee, Shareholder) William Spreen, PharmD, ViiV Healthcare (Employee, Shareholder) Sandy Griffith, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) David Margolis, MD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee)

1021. HIV-1 RNA Blips and Low-Level Replication During Phase III/IIIb Cabotegravir + Rilpivirine Long-Acting Studies Are Similar to Oral 3-Drug Therapy and Not Associated with Week 48 Virologic Outcome

Background

Phase III/IIIb studies demonstrated cabotegravir (CAB) + rilpivirine (RPV) long-acting (LA) dosed every 4 weeks (Q4W) was noninferior to current antiviral regimen (CAR) (FLAIR and ATLAS) and CAB + RPV LA dosed every 8 weeks (Q8W) was noninferior to Q4W (ATLAS-2M) through Week 48 (W48). HIV-1 ribonucleic acid (RNA) blips (viral load [VL] ≥50 to < 200 c/mL) are common during antiretroviral therapy (ART) and generally not associated with subsequent virologic failure (2 consecutive HIV-1 RNA ≥200 c/mL). We compared the frequency of HIV-1 RNA blips and low-level qualitative and quantitative HIV-1 RNA replication among participants treated with CAB+RPV LA and oral CAR and assessed impact on virologic outcome.

Methods

Plasma samples collected at study visits were analyzed for HIV-1 RNA viral load using the Abbott RealTime HIV-1 assay and qualitative target detected (TD) or target not detected (TND) outcomes were provided for HIV-1 RNA < 40 c/mL. The HIV-1 SuperLow assay (bioMONTR Labs) was used to measure HIV-1 RNA < 2 c/mL at Baseline and W48.

Results

The proportion of participants with HIV-1 RNA blips was similar overall between Q4W CAB + RPV LA and CAR arms in FLAIR (38/283 [13%] vs 39/283 [14%]) and ATLAS (17/308 [6%] vs 23/308 [7%]). Presence of HIV-1 RNA blips in either arm was not associated with virologic non-response at W48 (HIV-1 RNA ≥50 c/mL per US Food and Drug Administration Snapshot). In ATLAS-2M, HIV-1 RNA blips were observed in 32/523 (6%; Q4W) and 18/522 (3%; Q8W) of participants, with W48 virologic nonresponse in 2 Q4W and 0 Q8W participants. TD outcomes at individual study visits were comparable between study arms for the 3 studies. At W48, the proportion of participants with HIV-1 RNA < 2 c/mL was similar to Baseline and similar between treatment groups in all studies.

Conclusion

The proportions of study participants with HIV-1 RNA blips, TD viral load results, and HIV-1 < 2 c/mL were similar between the Q4W and Q8W CAB+RPV LA and the oral 3-drug CAR arms through W48 in phase III/IIIb studies. HIV-1 RNA blips did not predict virologic nonresponse (Snapshot analysis) at W48.

Disclosures

Christine L. Talarico, M.S, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Sterling Wu, PhD, GlaxoSmithKline (Employee, Shareholder) Marty St. Clair, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Veerle Van Eygen, MSc, Janssen Pharmaceutica NV (Employee) Krischan J. Hudson, PhD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Sandy Griffith, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Conn M. Harrington, BA, ViiV Healthcare (Employee) Jan van Lunzen, MD, PhD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) David Margolis, MD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) William Spreen, PharmD, ViiV Healthcare (Employee, Shareholder)

638. Safety, Efficacy, and Durability of Long-Acting CAB and RPV as Maintenance Therapy for HIV-1 Infection: LATTE-2 Week 256 Results

Background

Long-acting (LA) injectable suspensions of cabotegravir (CAB) & rilpivirine (RPV) are in phase III development. LATTE-2 W160 results demonstrated high rates of virologic response & overall tolerability. This W256 analysis evaluated long-term efficacy, safety, & tolerability of every 8-week (Q8W) & 4-week (Q4W) intramuscular (IM) dosing.

Methods

LATTE-2 is a phase IIb, multicenter, parallel arm, open-label study in antiretroviral therapy–naive adults with HIV. After a 20-week Induction Period on oral CAB+abacavir/lamivudine, participants (pts) with plasma HIV-1 RNA&lt; 50c/mL were randomized 2:2:1 to IM CAB LA+RPV LA Q8W, Q4W, or continue oral (PO) regimen in the Maintenance Period (MP). After W96, pts on IM regimens continued their current MP regimen. Pts randomized to PO in MP chose a Q8W or Q4W IM regimen in the Extension Period (EP). W256 analysis of MP & EP included virologic success with HIV-1 RNA&lt; 50 c/mL (Food & Drug Administration Snapshot analysis), protocol-defined virologic failure (PDVF), & safety (intention-to-treat–Maintenance Exposed population).

Results

At W256, 88% (101/115; Q8W) & 74% (85/115; Q4W) of randomized IM pts had HIV-1 RNA&lt; 50 c/mL, as did 93% (41/44) of PO to IM pts. No pt developed PDVF after W48. In the randomized IM arm (MP & EP), excluding injection-site reactions (ISRs), nasopharyngitis (45%), diarrhea (28%), & headache (24%) were the most common adverse events (AEs), with 34% (39/115; Q8W) & 33% (38/115; Q4W) of pts reporting AEs ≥grade 3, of which 12% (14/115; Q8W) & 11% (13/115; Q4W) were drug related. 3% (3/115; Q8W) & 17% (20/115; Q4W) of pts had AEs leading to withdrawal. 22% (25/115; Q8W) & 23% (27/115; Q4W) reported serious AEs (3 were drug related). In the PO to IM arm (EP only), most common AEs excluding ISRs were nasopharyngitis (25%), influenza (23%), & back pain (18%). 23% (10/44) reported AEs ≥grade 3 & 5% (2/44) had AEs leading to withdrawal. Majority of ISRs were mild/moderate pain & discomfort. &lt; 1% of ISRs were severe, with 5 pts discontinuing due to ISRs.

Table 1

Conclusion

CAB+RPV LA injectable therapy, administered Q8W or Q4W, demonstrated high rates of virologic response & tolerability through 5 years. W256 results add to previous results & demonstrate long-term durability of CAB+RPV LA for people living with HIV.

Disclosures

Keith Henry, MD, Gilead (Research Grant or Support, Paid to institution)GSK/ViiV (Research Grant or Support, Paid to institution)Janssen (Research Grant or Support, Paid to institution)Merck (Research Grant or Support, Paid to institution) Daniel Podzamczer, MD, PhD, Gilead (Grant/Research Support, Advisor or Review Panel member)Janssen Pharmaceutica (Grant/Research Support, Advisor or Review Panel member)Merck Sharp & Dohme (Grant/Research Support, Advisor or Review Panel member)ViiV Healthcare (Grant/Research Support, Advisor or Review Panel member) Mar Masiá, MD, PhD, Janssen Pharmaceutica (Consultant, Other Financial or Material Support, Travel/accommodations/meeting expenses)Merck Sharp & Dohme (Consultant, Other Financial or Material Support, Travel/accommodations/meeting expenses)ViiV Healthcare (Consultant, Other Financial or Material Support, Travel/accommodations/meeting expenses) Hans Jaeger, MD, Abbvie (Consultant, Speaker’s Bureau)Gilead Sciences (Consultant, Speaker’s Bureau)Janssen (Consultant, Speaker’s Bureau)MSD Sharp & Dohme (Consultant, Speaker’s Bureau)ViiV Healthcare (Consultant, Research Grant or Support, Speaker’s Bureau) Marie-Aude Khuong-Josses, MD, Viiv HC (Advisor or Review Panel member) Kenneth Sutton, MA, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Cynthia C. McCoig, MD, ViiV Healthcare (Employee) Kati Vandermeulen, MSC, Janssen Pharmaceutica (Employee, Shareholder) Rodica Van Solingen-Ristea, MD, Janssen R&D (Employee) William Spreen, PharmD, ViiV Healthcare (Employee, Shareholder) David Margolis, MD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee)

1029. Long-Term Patient Adherence and Management of Treatment Interruptions With Long-Acting Injectable Cabotegravir + Rilpivirine for Maintenance Therapy in Phase IIb/III Studies

Background

Cabotegravir (CAB) and rilpivirine (RPV) are under development as a novel long-acting (LA) regimen for maintenance of HIV virologic suppression. Pooled data from pivotal phase III trials demonstrated noninferiority of CAB + RPV LA given as gluteal intramuscular injections vs current antiretroviral regimen (CAR) on the primary endpoint of HIV-1 ribonucleic acid (RNA) ≥50c/mL at Week 48, with high levels of adherence. Long-term adherence to dosing visits and outcomes after use of oral CAB+RPV to cover planned missed injections in FLAIR through Week 96 and in LATTE-2 through Week 256 is reported here.

Methods

Virologically suppressed participants (HIV-1 RNA < 50c/mL) were randomized to switch to CAB+RPV LA or to continue CAR. On-time injections occurred every 4 weeks or every 8 weeks (LATTE-2 only) within a ±7-day dosing window of the projected dosing date. Adherence to LA therapy was calculated as the number of on-time injection visits divided by the number of expected dosing visits through the period of follow up. Injection visits outside the prespecified window and missed injection visits with or without use of oral dosing were characterized.

Results

Of 6005 expected injection visits through Week 96 in FLAIR, 97% of injections were given within the allowed ±7-day dosing window, with 43% on the projected dosing date. 45 (< 1%) injection visits were early and 107 (2%) were late. Adherence to 9803 expected injection visits in LATTE-2, through Week 256, was similarly high, with 96% of injections given within the allowed ±7-day dosing window and 39% on the projected dosing date. For 31 missed injection visits in 18 participants across both trials, 30 were covered with oral CAB+RPV, with all participants maintaining HIV-1 RNA < 50c/mL through the last study visit. In those participants who used oral CAB + RPV for planned treatment interruptions, 3 had repeat use on ≥2 separate occasions.

Conclusion

Participants maintained high levels of long-term adherence to CAB+RPV LA, through 2-5 years of follow up, with 97% of injections given within the ±7-day dosing window in the FLAIR and LATTE-2 clinical trials. Oral CAB+RPV to cover planned missed visits provides an effective strategy to maintain virologic suppression during short periods of LA treatment interruption.

Disclosures

Paula Teichner, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Sterling Wu, PhD, GlaxoSmithKline (Employee, Shareholder) David Dorey, MMATH, GlaxoSmithKline Inc. (Employee, Shareholder) Ronald D’Amico, DO, MSc, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Sandy Griffith, PharmD, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Kenneth Sutton, MA, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Cynthia C. McCoig, MD, ViiV Healthcare (Employee) Joseph Polli, PhD, FAAPS, ViiV Healthcare (Employee) David Margolis, MD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Rodica Van Solingen-Ristea, MD, Janssen R&D (Employee) Kati Vandermeulen, M.SC., Janssen Pharmaceutica (Employee, Shareholder) William Spreen, PharmD, ViiV Healthcare (Employee, Shareholder) Parul Patel, PharmD, ViiV Healthcare (Employee)

116. Antiviral Activity and Safety of Long-acting Cabotegravir (CAB LA) Plus Long-acting Rilpivirine (RPV LA), Administered Every 2 Months (Q2M), in Hiv-positive Subjects: Results from the POLAR Study

Background

Long-acting (LA) cabotegravir (CAB) and rilpivirine (RPV) injectable suspensions have demonstrated efficacy in phase III studies. POLAR assessed antiviral activity and safety of CAB LA+RPV LA, administered every 2 mos (Q2M), in HIV-1 infected, antiretroviral therapy–experienced adults who completed LATTE and received once-daily oral CAB30mg+RPV25mg treatment.

Methods

POLAR is a phase IIb, multicenter, open-label, rollover study in 97 virologically suppressed, HIV-infected adults. LATTE participants who completed ≥312 weeks on study, with plasma HIV-1RNA< 50c/mL at screening, were eligible for POLAR and offered the option to switch to CAB LA+RPV LA Q2M or to the oral fixed dose combination of dolutegravir (DTG)/rilpivirine (RPV) once daily, for continued maintenance of HIV-1RNA suppression. 90 participants chose CAB LA+RPV LA and 7 participants chose oral DTG/RPV. The primary outcome measure was proportion of participants with plasma HIV-1RNA≥50c/mL after 12 mos (M12) of therapy. Safety and laboratory measures were assessed throughout the study. Participants selecting LA treatment completed satisfaction and quality-of-life questionnaires at Day 1, M6, and M12.

Results

At M12, no participant had HIV-1RNA≥50c/mL or protocol defined virologic failure (confirmed plasma HIV-1RNA > 200c/mL). Excluding injection-site reactions (ISRs), nasopharyngitis (11%), upper respiratory tract infection (11%), diarrhea (10%), and pyrexia (10%) were the most commonly reported adverse events (AEs) in the Q2M arm. 10% (9/90) of Q2M participants reported AEs ≥grade 3; 0 were drug related. 2% (2/90) of Q2M participants had AEs leading to withdrawal. 6% (5/90) of participants reported serious AEs (1 considered drug-related). Over 12 mo, 1534 injections were administered; 463 ISRs were reported (30%; all grade 1/2 [84%/16%]); resolution of ISRs occurred after a median of 3 days. Minimal changes in lab parameters were observed in participants across 12 mo. 88% of participants who received LA therapy preferred CAB LA+RPV LA vs oral therapy.

Table 1

Table 2

Conclusion

CAB LA+RPV LA, administered Q2M, resulted in durable virologic suppression, an acceptable tolerability profile, and high levels of participant satisfaction over the first 12 mo of treatment in POLAR.

Disclosures

Anthony Mills, MD, Gilead (Grant/Research Support, Advisor or Review Panel member)Janssen Pharmaceutica (Grant/Research Support, Advisor or Review Panel member)Merck (Grant/Research Support, Advisor or Review Panel member)Shionogi (Grant/Research Support)ViiV Healthcare (Grant/Research Support, Advisor or Review Panel member) Gary J. Richmond, MD, FACP, FCCP, Gilead (Scientific Research Study Investigator)TaiMed (Scientific Research Study Investigator)Viv (Scientific Research Study Investigator) Cheryl Newman, MD, Gilead (Grant/Research Support)GlaxoSmithKline (Grant/Research Support, Speaker’s Bureau)ViiV Healthcare (Research Grant or Support, Speaker’s Bureau) Olayemi Osiyemi, M.D, GlaxoSmithKline (Advisor or Review Panel member, Speaker’s Bureau)ViiV Healthcare (Advisor or Review Panel member, Speaker’s Bureau) Jerry Cade, MD, Gilead (Consultant, Research Grant or Support, Speaker’s Bureau)Janssen Pharmaceutica (Consultant)Merck (Consultant, Research Grant or Support, Speaker’s Bureau)ViiV Healthcare (Consultant, Research Grant or Support) Cynthia Brinson, MD, Gilead (Advisor or Review Panel member, Speaker’s Bureau)ViiV Healthcare (Advisor or Review Panel member, Speaker’s Bureau) Nisha Andany, MD, MPH, FRCPC, Gilead Sciences (Scientific Research Study Investigator)GlaxoSmithKline (Scientific Research Study Investigator)Janssen (Scientific Research Study Investigator) David Margolis, MD, MPH, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Kenneth Sutton, MA, GlaxoSmithKline (Shareholder)ViiV Healthcare (Employee) Viviana Wilches, HBSc, MBiotech, GlaxoSmithKline (Employee, Shareholder) Jeremy Roberts, MSc, GSK (Employee) Cynthia C. McCoig, MD, ViiV Healthcare (Employee) Kati Vandermeulen, MSC, Janssen Pharmaceutica (Employee, Shareholder) William Spreen, PharmD, ViiV Healthcare (Employee, Shareholder)

Effect of rifabutin on the pharmacokinetics of oral cabotegravir in healthy subjects

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 noncompartmental 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 (AUC_0-τ), maximum observed plasma concentration (C_max) and concentration at the end of the dosing interval (C_τ) 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.

Long-Acting Cabotegravir Protects Macaques Against Repeated Penile Simian-Human Immunodeficiency Virus Exposures

We used a novel penile simian-human immunodeficiency virus (SHIV) transmission model to investigate whether long-acting cabotegravir (CAB LA) prevents penile SHIV acquisition in macaques. Twenty-two macaques were exposed to SHIV via the foreskin and urethra once weekly for 12 weeks. Of these, 6 received human-equivalent doses of CAB LA, 6 received oral emtricitabine/tenofovir disoproxil fumarate, and 10 were untreated. The efficacy of CAB LA was high (94.4%; 95% confidence interval, 58.2%–99.3%) and similar to that seen with oral emtricitabine/tenofovir disoproxil fumarate (94.0%; 55.1%–99.2%). The high efficacy of CAB LA in the penile transmission model supports extending the clinical advancement of CAB LA preexposure prophylaxis to heterosexual men.

2495. Pharmacokinetics of Cabotegravir (CAB) and Rilpivirine (RPV) Long-Acting (LA) Injectables in HIV-infected Individuals through 48 Weeks in the FLAIR and ATLAS Phase 3 Studies

Background

Monthly injectable CAB LA + RPV LA was noninferior to daily oral 3-drug antiretroviral therapy in HIV-1 virologically suppressed adults. CAB and RPV pharmacokinetics (PK) were assessed during the 48 Week maintenance period of the ATLAS and FLAIR Phase 3 studies.

Methods

Patients received oral CAB 30 mg + RPV 25 mg once daily for 4 weeks to assess individual tolerability prior to intramuscular (IM) injections of CAB LA 600 mg + RPV LA 900 mg followed by CAB LA 400 mg + RPV LA 600 mg every 4 weeks. Plasma CAB and RPV concentrations were measured pre-and post-dose at select visits using validated analytical methods.

Results

Baseline demographics for the pooled randomized ATLAS and FLAIR population (n = 591, LA arms) were: median age 38 years, 27% female, 18% African American, median BMI 25 kg/m² (range: 15 – 51). CAB and RPV plasma concentrations at select visits are summarized in the table. After initial IM doses, mean CAB and RPV troughs were well above their respective in vitro PA-IC90 values (CAB, 0.166 μg/mL; RPV 12 ng/mL). At Week 48, mean CAB troughs were 17x PA-IC90 and between oral CAB 10–30 mg exposures. Similarly, mean RPV troughs were 7x PA-IC90 and remained within the exposure range following oral RPV 25 mg once daily. 80% of RPV steady-state was achieved by Week 48 and 100% for CAB by Week 44. Initial CAB concentrations in females and those with BMI ≥30 kg/m² were lower due to slower absorption but this difference resolved by Week 48. For RPV, there was no absorption difference by gender or BMI.

Conclusion

CAB and RPV PK were consistent between studies achieving therapeutic concentrations within the first dosing interval that steadily increased over time through Week 48, for both males and females and irrespective of BMI. CAB LA + RPV LA provided compatible PK profiles following monthly IM dosing in a diverse patient population through 48 weeks.

Disclosures

All authors: No reported disclosures.

1532. Population Pharmacokinetic (PPK) Modeling and Simulation of Long-Acting (LA) Cabotegravir (CAB) to Inform Strategies Following Dosing Interruptions in HIV-1-Infected Subjects

Background

CAB is an integrase strand transfer inhibitor under investigation as an injectable LA formulation for the treatment and prevention of HIV, and as a tablet formulation as an oral lead-in (OLI) and bridging treatment for dose interruptions. The monthly injection regimen of CAB LA and rilpivirine (RPV) LA was noninferior to standard oral therapy in maintaining HIV-1 suppression in Phase 3 trials. PPK modeling and simulation was used to inform strategies for managing dosing interruptions.

Methods

A 2-compartment model with first-order oral and LA absorption and elimination adequately described the data from 1,647 healthy (28%) and HIV-infected (72%) adult subjects in 16 studies. Gender was a significant covariate on LA absorption; therefore, simulations of 5,000 virtual subjects were performed using a 4:1 male:female ratio to ensure 1,000 representative females and covariate sampling with replacement from the analysis dataset. One- to 12-week delays in dosing of the second, third, and fourth injection were simulated, and predicted troughs were compared with the 5th percentile (0.65 μg/mL) of trough concentrations following the first injection in Phase 3. Simulations of 1–2 months of oral bridging with CAB 30 mg once daily from time of a missed injection until CAB LA dosing resumed were performed, with the median Cmax (13.1 μg/mL) observed following oral CAB 60mg once daily in Phase 2b as an upper reference.

Results

Proportions of subjects predicted to achieve target plasma CAB trough concentrations are shown by length of delay and injection visit in Table 1. Oral bridging with CAB 30mg once daily starting at the time of a planned missed injection is predicted to provide exposures within ranges observed in clinical studies (Figure 1).

Conclusion

Dosing delays of up to one week appear to have minimal impact, but the effect is more likely to become problematic with longer delays, particularly in the first few months of dosing. Oral bridging provides therapeutic and safe exposures for planned interruptions in LA dosing. Regardless of use of oral bridging, simulations support resuming CAB LA dosing for interruptions <1 month (<2 months between injections) and reinitiating CAB LA with a loading dose and subsequent monthly injections for interruptions ≥ 1 month (≥ 2 months between injections).

Disclosures

All authors: No reported disclosures.

884. Patient Adherence to Long-Acting Injectable Cabotegravir + Rilpivirine Through 48 Weeks of Maintenance Therapy in the Phase 3 ATLAS and FLAIR Studies

Background

Cabotegravir (CAB) and rilpivirine (RPV) are under development as a novel long-acting (LA) regimen for maintenance of HIV virologic suppression. Pooled Week 48 data from pivotal Phase 3 trials demonstrated noninferiority of CAB LA + RPV LA vs. current antiretroviral regimen (CAR) on the primary endpoint, proportion of subjects with HIV-1 RNA ≥50 c/mL (1.9% and 1.7%, respectively). Adherence to dosing visits, use of oral dosing (bridging) to cover planned missed injections and injection tolerability were examined for subjects in the ATLAS and FLAIR studies.

Methods

Virologically suppressed subjects (HIV-1 RNA < 50 c/mL) were randomized to switch to CAB LA + RPV LA or to continue CAR. On-time injections occurred Q4 weeks within a +7-day dosing window of the projected dosing date. Adherence to LA therapy was calculated as the number of on-time injection visits divided by the number of expected dosing visits through Week 48. Injection visits outside the pre-specified window and missed injection visits with/without the use of oral dosing were quantified. Injection tolerability was assessed via adverse event reporting.

Results

A total of 14,682 injections of CAB and RPV were administered to 581 subjects during 6,920 injection visits. 98% of injection visits took place within the allowed ±7-day dosing window with 3,194 (46%) on the projected dosing date. Forty-six (<1%) injection visits were early and 106 (2%) were late. Oral bridging was used in 16 subjects overall; 8 planned missed injection visits were successfully covered, with no change to virologic suppression status. No subject with HIV-1 RNA ≥ 50 c/mL at Week 48 had missed/late injection visits. 25% (3,663/14,682) of injections were associated with local injection site reactions (ISRs). The most common ISR was pain (3,087/3,663 = 84%). Most ISRs were grade 1–2 (99%), short duration (median 3 days), with few associated discontinuations (<1%).

Conclusion

Subjects receiving CAB LA + RPV LA demonstrated high rates of adherence to injection visits through week 48, with 98% of injections occurring within the ±7-day dosing window. Oral bridging with CAB and RPV was an effective strategy for maintaining viral load suppression to cover missed injection visits. Injections were well-tolerated with few associated discontinuations.

Disclosures

All Authors: No reported Disclosures.

2840. Long-term Efficacy, Safety, and Durability of CAB and RPV as Two Drug Oral Maintenance Therapy: LATTE Week 312 Results

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 <50 c/mL immediately prior to W24 discontinued NRTIs and began RPV 25 mg as a two-drug oral maintenance regimen through W96. No change was made to the EFV arm. After W96, at the start of the open-label (OL) phase, all patients randomized to CAB were given the option to continue and switch to the sponsor-selected dose of oral CAB 30 mg. EFV patients completed the study at W96. The OL phase was completed at W312 (288 weeks on CAB + RPV). Successful CAB + RPV patients transitioned to the POLAR study (NCT03639311).

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 <50 c/mL, 9% had HIV-1 RNA ≥ 50 c/mL, and 25% were categorized as “No Virologic Data” by Snapshot at W312 (ITT-ME). There were 11 protocol-defined virologic failures (PDVF) on CAB; only 2 occurring after W144. Six patients developed treatment emergent (TE) resistance to one or both agents during the study; of which 4 patients developed TE major INI resistance mutations, 3 after W96. The median increase in CD4+ cell count from Baseline was 393 cells/mm³ (−174 to 1118). During the maintenance and OL phases, 4% of CAB patients reported drug-related AEs ≥ Grade 2; SAEs occurred in 9% of CAB patients (none drug related); 3% of CAB patients withdrew due to AEs. 43% of CAB patients who entered maintenance phase reported TE lab abnormalities ≥ Grade 3.

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.

Patient-reported tolerability and acceptability of cabotegravir + rilpivirine long-acting injections for the treatment of HIV-1 infection: 96-week results from the randomized LATTE-2 study

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.gov identifier NCT02120352) showed that cabotegravir LA + rilpivirine LA maintained virologic suppression through 96 weeks and included further exploration of patient-reported treatment outcomes with an LA injectable form of treatment.Methods: Two-hundred and eighty-six virologically suppressed participants on oral cabotegravir + abacavir/lamivudine once-daily tablets (induction period) were randomized to cabotegravir LA + rilpivirine LA once every 4 weeks (n = 115), once every 8 weeks (n = 115), or the continuation of the oral tablet regimen (n = 56) during the maintenance period. Patient-reported outcome measures included the HIV Medications Questionnaire (HIVMQ) and the HIV Treatment Satisfaction Questionnaire status (HIVTSQ[s]) and change (HIVTSQ[c]) versions at prespecified study visits through Week 96 of the randomized maintenance period.Results: Most participants in the LA injectable groups reported injection-site-related adverse events; however, participants in the 4-week (median HIVTSQ[s] total score, 63.5; post hoc P = 0.02) and 8-week (65.0; post hoc P < 0.001) LA injectable groups were significantly more satisfied with treatment than participants in the oral maintenance group (60.0) at Week 96. This was consistent with results from the HIVTSQ[c] at Week 32, which revealed that participants in both LA groups were significantly more satisfied with therapy compared with patients receiving oral ART (both post hoc P < 0.001).Conclusion: Participants who received LA injectable therapy had high levels of treatment satisfaction and favorably viewed convenience and lifestyle-related aspects of the therapy.

Drug resistance emergence in macaques administered cabotegravir long-acting for pre-exposure prophylaxis during acute SHIV infection

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.

Effect of a High-Fat Meal on the Pharmacokinetics of the HIV Integrase Inhibitor Cabotegravir

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.

Pharmacokinetics of Cabotegravir in Subjects with Severe Renal Impairment

Background

Cabotegravir (CAB) is an integrase inhibitor in phase 3 clinical trials for the treatment and prevention of HIV. CAB undergoes glucuronidation via UGT1A1 with <1% renal elimination of unchanged CAB. Renal impairment may affect PK of drugs that are primarily metabolized or secreted in bile; thus impact of renal impairment on CAB pharmacokinetics was evaluated.

Methods

This was a multi-center, single-dose study of oral CAB 30mg administered to subjects with severe renal impairment (creatinine clearance [CLcr] <30 mL/minute; not on renal replacement therapy) and to healthy controls (CLcr ≥90 mL/minute) matched for gender, age (±10 years), and body mass index (BMI) (±25%) (8 per group). Serial PK for plasma CAB concentrations were collected through 168 hours post dose and unbound CAB concentrations determined at 2 and 24 hours post dose. Non-compartmental PK analysis was performed; geometric least squares (GLS) mean ratios and 90% confidence intervals (CI) were generated.

Results

Sixteen subjects completed study; 12 (75%) male, mean age 54 years (range:35–69), mean BMI 28 kg/m² (range: 24–35), and mean CLcr 22 mL/minute (range: 17–29) and 121 mL/minute (range: 95–162) for renal impaired and healthy subjects, respectively. CAB PK parameters were similar between severe renal impairment and healthy subjects. Based on preliminary PK, GLS mean ratios (90% CI) for AUC(0-¥), Cmax, C24, CL/F, and t1/2 were 0.97 (0.835, 1.14), 1.01 (0.865, 1.17), 1.02 (0.868, 1.20), 1.03 (0.881, 1.20) and 0.93 (0.831, 1.04), respectively. Although highly protein bound, the unbound fraction was higher in subjects with severe renal impairment with GLS mean ratio (90%CI) of 1.31 (0.843, 2.03) at 2 hours and 1.51 (1.19, 1.92) at 24 hours post dose. One renal impairment subject developed grade 3 lipase elevation considered drug-related by investigator, otherwise all reported adverse events (AE) were Grade 1 in severity with no serious AEs reported.

Conclusion

Plasma CAB exposures in subjects with severe renal impairment were similar to healthy subjects; therefore, no dose adjustment of CAB is required in renal impairment. Although no data are available, CAB PK is not expected to be affected in subjects undergoing dialysis given CAB’s non-renal clearance and high plasma protein binding (~99%).

Disclosures

R. Parasrampuria, GlaxoSmithKline: Employee and Shareholder, Salary; S. Ford, PAREXEL International: Employee, Salary; Y. Lou, PAREXEL International: Employee, Salary; C. Fu, PAREXEL International: Employee, Salary; K. Bakshi, GlaxoSmithKline: Employee and Shareholder, Salary; A. Tenorio, ViiV Healthcare: Employee and Shareholder, Salary; C. Trezza, ViiV Healthcare: Employee and Shareholder, Salary; W. Spreen, ViiV Healthcare: Employee and Shareholder, Salary; P. Patel, ViiV Healthcare: Employee and Shareholder, Salary

Pharmacokinetics of Cabotegravir in Subjects with Moderate Hepatic Impairment

Background

Cabotegravir (CAB) is an integrase inhibitor in phase 3 clinical trials for the treatment and prevention of HIV. CAB undergoes hepatic metabolism primarily via UGT1A1; thus hepatic impairment has the potential to affect CAB exposure.

Methods

This was a multi-center, single-dose, open-label, parallel group study to evaluate the effect of moderate hepatic impairment on the pharmacokinetics (PK) and safety of CAB. Adults with moderate hepatic impairment as determined by Child-Pugh classification score of 7–9 (n = 8) and matched healthy control subjects (n = 8) were enrolled. Control subjects were matched for gender, age (±10 years), and body mass index (BMI) (±25%). Subjects received oral CAB 30 mg as a single dose in the fasted state followed by serial PK sampling for 168 hours. CAB unbound concentrations at 2 and 24 hours after dosing were determined by equilibrium dialysis. Non-compartmental PK analysis was performed; geometric least squares (GLS) mean ratios (hepatic impaired group/control group) and 90% confidence intervals (CI) were generated.

Results

Sixteen subjects completed study; 12 (75%) male, mean age 59 years (range: 51–67), mean BMI 29 kg/m2 (range: 21–37), and total Child Pugh score in range of 7–9. CAB PK parameters were similar between subjects with moderate hepatic impairment and matched healthy subjects. The GLS mean ratios (90% CI) for AUC(0-∞), Cmax, C24, CL/F, and t1/2 were 0.73 (0.50, 1.06), 0.69 (0.51, 0.93), 0.73 (0.53, 1.02), 1.38 (0.95, 2.01), and 0.82 (0.65, 1.04), respectively. Although highly protein bound, the unbound fraction of CAB was increased in subjects with moderate hepatic impairment relative to healthy subjects with GLS mean ratio (90%CI) of 2.14 (1.57, 2.90) at 2 hours post dose and 1.90 (1.14, 3.18) at 24 hours post dose; this was associated with lower serum albumin concentrations and was not considered clinically significant. All adverse events (AE) were reported as mild (Grade 1) to moderate (Grade 2) in severity and no serious AEs were reported.

Conclusion

Plasma exposures of CAB in subjects with moderate hepatic impairment were similar to those in healthy subjects. No dose adjustment of CAB is required for subjects with mild to moderate hepatic impairment.

Disclosures

J. S. Shaik, GlaxoSmithKline: Employee and Shareholder, Salary; S. Ford, PAREXEL International: Employee, Salary; Y. Lou, PAREXEL International: Employee, Salary; Z. Zhang, PAREXEL International: Employee, Salary; K. Bakshi, GlaxoSmithKline: Employee and Shareholder, Salary; A. Tenorio, ViiV Healthcare: Employee and Shareholder, Salary; C. Trezza, ViiV Healthcare: Employee and Shareholder, Salary; W. Spreen, ViiV Healthcare: Employee and Shareholder, Salary; P. Patel, ViiV Healthcare: Employee and Shareholder, Salary

Lack of effect of oral cabotegravir on the pharmacokinetics of a levonorgestrel/ethinyl oestradiol-containing oral contraceptive in healthy adult women

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.

Pharmacokinetics, safety, and monotherapy antiviral activity of GSK1265744, an HIV integrase strand transfer inhibitor

BACKGROUND

GSK1265744 is an HIV integrase strand transfer inhibitor selected for clinical development.

OBJECTIVE

This first-time-in-human and phase IIa investigation assessed GSK1265744 antiviral activity, pharmacokinetics, safety, and tolerability in healthy and HIV-1-infected subjects.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

A randomized, placebo-controlled trial of abacavir intensification in HIV-1-infected adults with virologic suppression on a protease inhibitor-containing regimen

BACKGROUND AND OBJECTIVE

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.

METHODS

Zidovudine-experienced subjects (n=229) on therapy with indinavir + zidovudine + lamivudine with plasma HIV-1 RNA levels<500 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 RNAs>200 copies/mL) and treatment discontinuation.

RESULTS

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.

CONCLUSIONS

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.

Association of efavirenz hypersusceptibility with virologic response in ACTG 368, a randomized trial of abacavir (ABC) in combination with efavirenz (EFV) and indinavir (IDV) in HIV-infected subjects with prior nucleoside analog experience

PURPOSE

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.

METHOD AND RESULTS

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.

CONCLUSION

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.

PREDICT-1 (CNA106030): the first powered, prospective trial of pharmacogenetic screening to reduce drug adverse events

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-naïve 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.

Antiviral efficacy of abacavir in antiretroviral therapy-experienced adults harbouring HIV-1 with specific patterns of resistance to nucleoside reverse transcriptase inhibitors

OBJECTIVE

To evaluate HIV-1 reverse transcriptase genotypic and phenotypic indicators of resistance to abacavir (ABC) as predictors of ABC antiviral efficacy.

DESIGN

The 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.

METHODS

Baseline 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.

RESULTS

Overall, 68% of these therapy-experienced subjects had a virological response (>0.5 log10 or <400 copies/ml; 42% <400 copies/ml) 4 weeks after addition of ABC. Multivariable analyses revealed no significant difference in the response rate between subjects with wild-type virus and those carrying virus with 1-2 nucleoside reverse transcriptase inhibitor (NRTI)-associated mutations. At the 4-week time-point subjects harbouring virus with > or = 3 mutations associated with NRTI resistance were significantly less likely to respond to ABC than were subjects harbouring wild-type virus (P=0.015). However, at the last viral RNA measurement after addition of ABC (12-28 weeks), > or = 4 mutations were required to diminish virological response significantly (P=0.012). Phenotypic resistance was also predictive of antiviral response. Significant breakpoints were identified for virological responses for the PhenoSense HIV assay and the Antivirogram assay. CD4 responses generally paralleled the antiviral responses with a median increase of 55 cells/microl by weeks 12-28.

CONCLUSIONS

Virological 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.

Genetic variations in HLA-B region and hypersensitivity reactions to abacavir

Hypersensitivity to abacavir affects about 4% of patients who receive the drug for HIV-1 infection. We did a retrospective, case-control study to identify multiple markers in the vicinity of HLA-B associated with hypersensitivity reactions. HLA-B57 was present in 39 (46%) of 84 patients versus four (4%) of 113 controls (p<0 small middle dot0001). However, because of low numbers of women and other ethnic groups enrolled, these findings relate largely to white men. The lower sensitivity of HLA-B57 for predicting hypersensitivity to abacavir identified in this study compared with a previous report highlights that predictive values for markers will vary across populations. Clinical monitoring and management of hypersensitivity reactions among patients receiving abacavir must remain unchanged.

Mutations in HIV-1 reverse transcriptase during therapy with abacavir, lamivudine and zidovudine in HIV-1-infected adults with no prior antiretroviral therapy

OBJECTIVE

To evaluate HIV-1 reverse transcriptase (RT) drug resistance in patients receiving abacavir, lamivudine and zidovudine therapy.

METHODS

In a randomized, double-blind study, 173 antiretroviral treatment-naive HIV-1-infected adults received abacavir/lamivudine/zidovudine or lamivudine/zidovudine for up to 48 weeks. After week 16, patients could switch to open-label abacavir/lamivudine/zidovudine, and those with plasma HIV-1 RNA (vRNA) > 400 copies/ml could add other antiretrovirals. From weeks 11 to 48, samples with vRNA > 400 copies/ml were collected for genotyping and phenotyping.

RESULTS

At baseline, 90% of isolates were wild-type (WT). At week 16, vRNA was > 400 copies/ml in seven of 72 (10% patients receiving abacavir/lamivudine/zidovudine and in 41 of 66 (62%) receiving lamivudine/ zidovudine. At week 16, the genotypes in isolates from the abacavir/lamivudine/zidovudine group were M184V alone (n = 3 cases), WT (n = 3) and M184V plus thymidine analogue mutations (TAMs) (n = 1). The genotypes in isolates from the lamivudine/zidovudine group were M184V alone (n = 37), WT ( n= 1) and M184V plus TAMs (n = 3). In the four cases where M184V plus TAMs were detected some mutations were present at baseline. Despite detectable M184V in 74% of patients on lamivudine/zidovudine, addition of abacavir with or without another antiretroviral therapy resulted in a reduction in vRNA, with 42 of 65 (65%) patients having week 48 vRNA < 400 copies/ml (intent-to-treat with missing = failure). At week 48, the most common genotype was M184V alone in the abacavir/ lamivudine/zidovudine group (median vRNA 1-2 log,10 below baseline), and M184V with or without TAMs in patients originally assigned to lamivudine/zidovudine. At week 48, phenotypic results were obtained for 11 isolates for patients from both arms, and all had reduced susceptibility to lamivudine but all remained sensitive to stavudine, all protease inhibitors and all non-nucleoside reverse transcriptase inhibitors. Three, three and two isolates had reduced susceptibility to abacavir, didanosine and zidovudine, respectively.

CONCLUSIONS

Abacavir retained efficacy against isolates with the M184V genotype alone. TAMs did not develop during 48 weeks of abacavir/lamivudine/zidovudine therapy and were uncommon when abacavir was added after 16 weeks of lamivudine/zidovudine therapy. Limited mutations upon rebound on this triple nucleoside combination allows for several subsequent treatment options.

Mutations in HIV-1 Reverse Transcriptase during Therapy with Abacavir, Lamivudine and Zidovudine in HIV-1-Infected Adults with No Prior Antiretroviral Therapy

Objective

To evaluate HIV-1 reverse transcriptase (RT) drug resistance in patients receiving abacavir, lamivudine and zidovudine therapy.

Methods

In a randomized, double-blind study, 173 anti-retroviral treatment-naive HIV-1-infected adults received abacavir/lamivudine/zidovudine or lamivudine/zidovudine for up to 48 weeks. After week 16, patients could switch to open-label abacavir/lamivudine/zidovudine, and those with plasma HIV-1 RNA (vRNA) >400 copies/ml could add other antiretrovirals. From weeks 16 to 48, samples with vRNA >400 copies/ml were collected for genotyping and phenotyping.

Results

At baseline, 90% of isolates were wild-type (WT). At week 16, vRNA was >400 copies/ml in seven of 72 (10%) patients receiving abacavir/lamivudine/zidovudine and in 41 of 66 (62%) receiving lamivudine/ zidovudine. At week 16, the genotypes in isolates from the abacavir/lamivudine/zidovudine group were M184V alone ( n=3 cases), WT ( n=3) and M184V plus thymidine analogue mutations (TAMs) ( n=1). The genotypes in isolates from the lamivudine/zidovudine group were M184V alone ( n=37), WT ( n=1) and M184V plus TAMs ( n=3). In the four cases where M184V plus TAMs were detected some mutations were present at baseline. Despite detectable M184V in 74% of patients on lamivudine/zidovudine, addition of abacavir with or without another antiretroviral therapy resulted in a reduction in vRNA, with 42 of 65 (65%) patients having week 48 vRNA <400 copies/ml (intent-to-treat with missing=failure). At week 48, the most common genotype was M184V alone in the abacavir/ lamivudine/zidovudine group (median vRNA 1–2 log10 below baseline), and M184V with or without TAMs in patients originally assigned to lamivudine/zidovudine. At week 48, phenotypic results were obtained for 11 isolates for patients from both arms, and all had reduced susceptibility to lamivudine but all remained sensitive to stavudine, all protease inhibitors and all non-nucleoside reverse transcriptase inhibitors. Three, three and two isolates had reduced susceptibility to abacavir, didanosine and zidovudine, respectively.

Conclusions

Abacavir retained efficacy against isolates with the M184V genotype alone. TAMs did not develop during 48 weeks of abacavir/lamivudine/zidovudine therapy and were uncommon when abacavir was added after 16 weeks of lamivudine/zidovudine therapy. Limited mutations upon rebound on this triple nucleoside combination allows for several subsequent treatment options.

Antiretroviral activity and safety of abacavir in combination with selected HIV-1 protease inhibitors in therapy-naive HIV-1-infected adults

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 > or = 100 cells/mm3, plasma HIV-1 RNA > or = 5,000 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 < or = 400 and < or = 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 < or = 400 copies/ml was 53, 50, 50, 41 and 56%, respectively, and the proportion with HIV-1 RNA < or = 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.

Abacavir-lamivudine-zidovudine vs indinavir-lamivudine-zidovudine in antiretroviral-naive HIV-infected adults: A randomized equivalence trial

CONTEXT

Abacavir, a nucleoside analogue, has demonstrated suppression of human immunodeficiency virus (HIV) replication alone and in combination therapy. However, the role of abacavir in a triple nucleoside combination regimen has not been evaluated against a standard protease inhibitor-containing regimen for initial antiretroviral treatment.

OBJECTIVE

To evaluate antiretroviral equivalence and safety of an abacavir-lamivudine-zidovudine regimen compared with an indinavir-lamivudine-zidovudine regimen.

DESIGN AND SETTING

A multicenter, phase 3, randomized, double-blind trial with an enrollment period from August 1997 to June 1998, with follow-up through 48 weeks at 73 clinical research units in the United States, Canada, Australia, and Europe.

PATIENTS

Five hundred sixty-two antiretroviral-naive, HIV-infected adults with a plasma HIV RNA level of at least 10 000 copies/mL and a CD4 cell count of at least 100 x 10(6)/L.

INTERVENTIONS

Patients were stratified by baseline HIV RNA level and randomly assigned to receive a combination tablet containing 150 mg of lamivudine and 300 mg of zidovudine twice daily plus either 300 mg of abacavir twice daily and indinavir placebo or 800 mg of indinavir every 8 hours daily plus abacavir placebo. After 16 weeks, patients with confirmed HIV RNA levels greater than 400 copies/mL were eligible to continue receiving randomized treatment or receive open-label therapy.

MAIN OUTCOME MEASURE

Virologic suppression, defined as HIV RNA concentration of 400 copies/mL or less at week 48.

RESULTS

The proportion of patients who met the end point of having an HIV RNA level of 400 copies/mL or less at week 48 was equivalent in the abacavir group (51% [133/262]) and in the indinavir group (51% [136/265]) with a treatment difference of -0.6% (95% confidence interval [CI], -9% to 8%). In patients with baseline HIV RNA levels greater than 100 000 copies/mL, the proportion of patients achieving less than 50 copies/mL was greater in the indinavir group than in the abacavir group with 45% (45/100) vs 31% (30/96) and a treatment diference of -14% (95% CI, -27% to 0%). The 2 treatments were comparable with respect to their effects on CD4 cell count. There was no difference between groups in the frequency of treatment-limiting adverse events or laboratory abnormalities. One death in the abacavir group was attributed to hypersensitivity reaction, which occurred following rechallenge with abacavir, approximately 3 weeks after initiating study treatment.

CONCLUSIONS

In this study of antiretroviral-naive HIV-infected adults, the triple nucleoside regimen of abacavir-lamivudine-zidovudine was equivalent to the regimen of indinavir-lamivudine-zidovudine in achieving a plasma HIV RNA level of less than 400 copies/mL at 48 weeks.

Antiretroviral Activity and Safety of Abacavir in Combination with Selected HIV-1 Protease Inhibitors in Therapy-Naive HIV-1-Infected Adults

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.

A randomized, double-blind study of triple nucleoside therapy of abacavir, lamivudine, and zidovudine versus lamivudine and zidovudine in previously treated human immunodeficiency virus type 1-infected children. The CNAA3006 Study Team

OBJECTIVES

Abacavir (ABC) is a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We compared the efficacy, safety, and tolerability of combination therapy with ABC, lamivudine (3TC), and zidovudine (ZDV) versus 3TC and ZDV in antiretroviral experienced HIV-1-infected children over 48 weeks.

METHODS

Two hundred five HIV-1-infected children who had received previous antiretroviral therapy and had CD4(+) cell counts >/=100 cells/mm(3) were stratified by age and by previous treatment. Participants were randomly assigned to receive ABC (8 mg/kg twice daily [BID]) plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2) BID; ABC/3TC/ZDV group) or ABC placebo plus 3TC (4 mg/kg BID) and ZDV (180 mg/m(2); 3TC/ZDV group). Participants who met a protocol-defined switch criteria (plasma HIV-1 RNA >0.5 log(10) copies/mL above baseline at week 8 or >10 000 copies/mL after week 16) had the option to switch to open-label ABC plus any antiretroviral combination or continue randomized therapy or withdraw from the study.

RESULTS

The Kaplan-Meier estimates (95% confidence interval) of the proportion of participants who maintained HIV-1 RNA levels </=10 000 copies/mL for 48 weeks or more was significantly better in the ABC/3TC/ZDV group compared with the 3TC/ZDV group: 33% (23%-42%) versus 21% (13%-29%). At week 48, the proportions of participants with HIV-1 RNA </=10 000 copies/mL were 36% versus 26% for the ABC/3TC/ZDV and 3TC/ZDV groups, respectively, by intent-to-treat analysis. For the subgroup of participants with baseline HIV-1 RNA >10 000 copies/mL, a significantly higher proportion of participants in the ABC/3TC/ZDV group had HIV-1 RNA </=10 000 copies/mL compared with the 3TC/ZDV group (29% vs 12%) but no difference was observed in the subgroup of participants with baseline HIV-1 RNA </=10 000 copies/mL (78% vs 72%). The median changes from baseline in CD4(+) cell counts were greater in the ABC/3TC/ZDV group than in the 3TC/ZDV group. Few participants (3%) experienced abacavir-related hypersensitivity reaction.

CONCLUSIONS

ABC, in combination with 3TC and ZDV, provides additional antiretroviral activity over 48 weeks, compared with combination therapy with 3TC and ZDV in antiretroviral experienced HIV-1-infected children. ABC was safe and generally well-tolerated and should be considered an active component of combination antiretroviral therapy in this pediatric population.

Cellular restoration in HIV infected persons treated with abacavir and a protease inhibitor: age inversely predicts naive CD4 cell count increase

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.

Immunological and virological responses in HIV-1-infected adults at early stage of established infection treated with highly active antiretroviral therapy

OBJECTIVE

To evaluate the immunological and virological responses to highly active antiretroviral therapy (HAART) in blood and lymphoid compartments of HIV-1-infected patients at an early stage of infection.

DESIGN

An open-label, observational, non-randomized, prospective trial of outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland.

SUBJECTS

Forty-one antiretroviral-naive HIV-1-infected adults with 400 CD4 T cells/microl or greater and 5000 plasma HIV-1-RNA copies/ml or greater were enrolled, and 32 finished the study. Forty-nine HIV-negative individuals were included as controls. All subjects gave written informed consent.

INTERVENTIONS

All patients received abacavir 300 mg by mouth every 12 h and amprenavir 1200 mg by mouth every 12 h for 72 weeks.

MAIN OUTCOME MEASURES

The extent of immune reconstitution in blood and lymph nodes after 72 weeks of HAART was evaluated, and compared with immunological measures of 49 HIV-negative subjects.

RESULTS

Virus replication was effectively suppressed (-3.5 log10 at week 72). Substantial increments of CD4 T cell count in blood and percentage in lymph nodes were observed over time, and these measures were comparable to HIV-negative subjects by week 24 in blood and by week 48 in lymph nodes. The increase was equally distributed between naive and memory CD4 T cells. Recovery of HIV-specific CD4 responses occurred in 40% of patients.

CONCLUSION

The initiation of HAART at an early stage of established HIV infection induces systemic quantitative normalization of CD4 T cells, a partial recovery of HIV-specific CD4 cell responses, and effective and durable suppression of virus replication.

Antiretroviral effect and safety of abacavir alone and in combination with zidovudine in HIV-infected adults. Abacavir Phase 2 Clinical Team

OBJECTIVES

To evaluate, over 12 weeks, the antiretroviral activity and safety of abacavir, used alone and in combination with zidovudine (ZDV), as treatment for HIV-1-infected subjects who had limited or no antiretroviral treatment.

DESIGN

Seventy-nine HIV-1-infected subjects, with CD4 cell counts 200-500 x 10(6)/l and <12 weeks of previous treatment with ZDV were enrolled in a multicenter study. Subjects were randomly assigned to one of four cohorts receiving abacavir monotherapy for the first 4 weeks (200, 400, or 600 mg every 8 h daily, or 300 mg every 12 h daily) and, thereafter, combination therapy of abacavir with 600 mg ZDV or ZDV placebo, administered in a double-blind manner for an additional 8 weeks.

METHODS

Antiretroviral activity was assessed by measuring changes in plasma HIV-1 RNA levels and CD4+ cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities during the 12-week period and for 4 weeks post-treatment.

RESULTS

Treatment with abacavir, alone or in combination with ZDV, produced marked decreases in plasma HIV-1 RNA loads and increases in CD4+ cell counts in all groups. At week 4, median plasma HIV-1 RNA loads decreased by 1.11-1.77 log10 copies/ml and median CD4+ cell counts increased by 63-111 x 10(6)/l in all groups. At week 12, median HIV-1 RNA loads decreased by 1.02-2.24 log10 copies/ml (abacavir monotherapy) and by 1.81-2.01 log10 copies/ml (abacavir-ZDV); median CD4+ cell counts increased by 79-195 x 10(6)/l (abacavir monotherapy) and by 93-142 x 10(6)/l (abacavir-ZDV). At week 12, the percentage of subjects who had plasma HIV-1 RNA levels below 400 and 40 copies/ml were 28 and 11%, respectively (abacavir monotherapy) and 69 and 22%, respectively (abacavir-ZDV). Eight subjects (10%) discontinued the study prematurely because of adverse events; nausea (n = 4) and hypersensitivity (n = 3) were the most common reasons for withdrawal. There were no deaths among the study subjects.

CONCLUSIONS

In HIV-infected subjects who have received little or no prior antiretroviral therapy, treatment with abacavir alone or in combination with ZDV is well tolerated and resulted in sustained improvements in key immunologic and virologic efficacy parameters through 12 weeks.

Limited CD4+ T-cell renewal in early HIV-1 infection: effect of highly active antiretroviral therapy

We show that the fraction of proliferating CD4+ lymphocytes is similar in HIV-infected subjects in the early stage of disease and in HIV-negative subjects, whereas the fraction of proliferating CD8+ lymphocytes is increased 6.8-fold in HIV-infected subjects. After initiation of antiviral therapy, there is a late increase in proliferating CD4+ T cells associated with the restoration of CD4+ T-cell counts. These results provide strong support for the idea of limited CD4+ T-cell renewal in the early stage of HIV infection and indicate that after effective suppression of virus replication, the mechanisms of CD4+ T-cell production are still functional in early HIV infection.