Dynamic changes in immune cell populations by AXL kinase targeting diminish liver inflammation and fibrosis in experimental MASH.

Background and aims: Metabolic dysfunction-associated steatohepatitis (MASH) is a significant health concern with limited treatment options. AXL, a receptor tyrosine kinase activated by the GAS6 ligand, promotes MASH through activation of hepatic stellate cells and inflammatory macrophages. This study identified cell subsets affected by MASH progression and the effect of AXL inhibition. Methods: Mice were fed chow or different fat-enriched diets to induce MASH, and small molecule AXL kinase inhibition with bemcentinib was evaluated. Gene expression was measured by qPCR. Time-of-flight mass cytometry (CyTOF) used single cells from dissociated livers, acquired on the Fluidigm Helios, and cell populations were studied using machine learning. Results: In mice fed different fat-enriched diets, liver steatosis alone was insufficient to elevate plasma soluble AXL (sAXL) levels. However, in conjunction with inflammation, sAXL increases, serving as an early indicator of steatohepatitis progression. Bemcentinib, an AXL inhibitor, effectively reduced proinflammatory responses in MASH models, even before fibrosis appearance. Utilizing CyTOF analysis, we detected a decreased population of Kupffer cells during MASH while promoting infiltration of monocytes/macrophages and CD8+ T cells. Bemcentinib partially restored Kupffer cells, reduced pDCs and GzmB- NK cells, and increased GzmB+CD8+ T cells and LSECs. Additionally, AXL inhibition enhanced a subtype of GzmB+CD8+ tissue-resident memory T cells characterized by CX3CR1 expression. Furthermore, bemcentinib altered the transcriptomic landscape associated with MASH progression, particularly in TLR signaling and inflammatory response, exhibiting differential cytokine expression in the plasma, consistent with liver repair and decreased inflammation. Conclusion: Our findings highlight sAXL as a biomarker for monitoring MASH progression and demonstrate that AXL targeting shifted liver macrophages and CD8+ T-cell subsets away from an inflammatory phenotype toward fibrotic resolution and organ healing, presenting a promising strategy for MASH treatment.

Pharmacokinetics and pharmacodynamics of the nucleoside sparing dual regimen containing rilpivirine plus darunavir/ritonavir in treatment-naïve HIV-1-infected individuals.

BACKGROUND: We aimed at investigating the antiviral activity and the pharmacokinetics of the dual antiretroviral (ARV) combination of rilpivirine plus darunavir/ritonavir 25/800/100 mg once-daily in naïve HIV-1-infected individuals (NHII) with different baseline viral loads. SETTINGS: Pharmacokinetic/pharmacodynamics study in ARV-naïve HIV-infected individuals. METHODS: The primary endpoint was the number of NHII with HIV-RNA < 40 copies/mL at week 48. Secondary endpoints included rilpivirine/darunavir/ritonavir pharmacokinetics, HIV-RNA decay, and changes in ECG QT interval. RESULTS: Thirty-six individuals were enrolled, 18 with a baseline viral load < 100,000 copies/mL (group A) and 18 with a baseline viral load > 100,000 copies/mL (group B). All but 1 (HIV-RNA = 63 copies/mL) subjects achieved viral load < 50 copies/mL by week 36, and all at week 48. Median (range) HIV-RNA reduction (Log10 copies/mL) was 1.3 (0.6-1.9) over the first week, with no differences between groups A and B. Geometric mean and 95%CI rilpivirine Cmax, Ctrough, AUC were 183 (165-239), 114 (104-109) ng/mL, 2966 (2704-3820) ng h/mL. No QTcF interval changes were recorded. CONCLUSIONS: rilpivirine/darunavir/ritonavir could be efficacious, with limited short-term toxicity in ARV-naïve patients. Although rilpivirine was co-administered with ritonavir, its exposure was within ranges measured during phase III trials.

First-in-Human Evaluation of the Safety and Immunogenicity of an Intranasally Administered Replication-Competent Sendai Virus-Vectored HIV Type 1 Gag Vaccine: Induction of Potent T-Cell or Antibody Responses in Prime-Boost Regimens.

BACKGROUND: We report the first-in-human safety and immunogenicity assessment of a prototype intranasally administered, replication-competent Sendai virus (SeV)-vectored, human immunodeficiency virus type 1 (HIV-1) vaccine. METHODS: Sixty-five HIV-1-uninfected adults in Kenya, Rwanda, and the United Kingdom were assigned to receive 1 of 4 prime-boost regimens (administered at 0 and 4 months, respectively; ratio of vaccine to placebo recipients, 12:4): priming with a lower-dose SeV-Gag given intranasally, followed by boosting with an adenovirus 35-vectored vaccine encoding HIV-1 Gag, reverse transcriptase, integrase, and Nef (Ad35-GRIN) given intramuscularly (SLA); priming with a higher-dose SeV-Gag given intranasally, followed by boosting with Ad35-GRIN given intramuscularly (SHA); priming with Ad35-GRIN given intramuscularly, followed by boosting with a higher-dose SeV-Gag given intranasally (ASH); and priming and boosting with a higher-dose SeV-Gag given intranasally (SHSH). RESULTS: All vaccine regimens were well tolerated. Gag-specific IFN-γ enzyme-linked immunospot-determined response rates and geometric mean responses were higher (96% and 248 spot-forming units, respectively) in groups primed with SeV-Gag and boosted with Ad35-GRIN (SLA and SHA) than those after a single dose of Ad35-GRIN (56% and 54 spot-forming units, respectively) or SeV-Gag (55% and 59 spot-forming units, respectively); responses persisted for ≥8 months after completion of the prime-boost regimen. Functional CD8+ T-cell responses with greater breadth, magnitude, and frequency in a viral inhibition assay were also seen in the SLA and SHA groups after Ad35-GRIN boost, compared with those who received either vaccine alone. SeV-Gag did not boost T-cell counts in the ASH group. In contrast, the highest Gag-specific antibody titers were seen in the ASH group. Mucosal antibody responses were sporadic. CONCLUSIONS: SeV-Gag primed functional, durable HIV-specific T-cell responses and boosted antibody responses. The prime-boost sequence appears to determine which arm of the immune response is stimulated. CLINICAL TRIALS REGISTRATION: NCT01705990.

An open-label, randomized study of the impact on insulin sensitivity, lipid profile and vascular inflammation by treatment with lopinavir/ritonavir or raltegravir in HIV-negative male volunteers.

BACKGROUND: We aimed to measure the effect of raltegravir (RAL) on insulin sensitivity and surrogates of cardiovascular risk in healthy HIV-seronegative volunteers compared to that of lopinavir/r (LPV/r), a positive control. METHODS: An open-label, two phase crossover study in HIV-negative male subjects randomized 1:1 to receive either 2 weeks of LPV/r followed by a 2-week washout period and 2 weeks of RAL, or RAL initially followed by LPV/r. A hyperinsulinaemic euglycaemic clamp was performed prior to and following each 2-week dosing phase. Fasting samples for lipids, adiponectin, leptin, vascular inflammatory biomarkers and CD36 were also taken. RESULTS: A total of 16 subjects completed the study. At the baseline visit the mean insulin-stimulated glucose disposal per unit insulin (M/I) was 7.97 and 8.30 for LPV/r and RAL, respectively. The mean (sem) percentage change from baseline was -16.10% (3.84) after 2 weeks of LPV/r and -0.43% (4.83) after 2 weeks of RAL. Absolute M/I was 25% lower for LPV/r than for RAL (P=0.001). Triglycerides and total cholesterol rose significantly with LPV/r (+0.5 mmol/l, P=0.002 and +0.4 mmol/l, P<0.0001), but were unchanged with RAL. Proathrogenic lipid subfractions of low-density lipoprotein (LDL) cholesterol increased with LPV/r and were unaffected with RAL. LDL peak and mean particle diameter and LDL I significantly decreased with LPV/r (P<0.05), and trend of increased LDL III was detected. High-sensitivity C-reactive protein declined with RAL (-0.2 mg/l, P=0.043) but was elevated after LPV/r (+0.25 mg/l, P=0.03). CONCLUSIONS: RAL was not associated with measurable change in glycaemic, metabolic or inflammatory effects.

Brief Report: Pharmacokinetic/Pharmacodynamic Investigation of Single-Dose Oral Maraviroc in the Context of HIV-1 Pre-exposure Prophylaxis.

To investigate the pharmacokinetics/pharmacodynamics of single-dose maraviroc 300 mg in HIV-1 exposure compartments. Maraviroc concentrations in blood, secretions (vaginal, urethral, oral, and rectal), and tissue (vaginal and rectal) were measured, and ex vivo challenge was performed in 54 healthy volunteers to study protection from HIV infection. Maraviroc Cmax occurred within 4 hours in most compartments. Concentrations from 4 to 72 hours were above intracellular (IC) IC90 in all compartments, range 15-8095 ng/mL. Mean AUC0-72 compartment-to-plasma ratios were highest in the rectum (45-819) and urethra (144) compared with the female genital tract (1.6-4.8) and saliva (0.2). No sex differences in AUC0-72 or Cmax were observed. No ex vivo protection from HIV-1BaL occurred in rectal or vaginal tissue. Despite high and sustained concentrations, single-dose maraviroc was not protective against ex vivo challenge of vaginal/rectal tissue.

Selection of Rilpivirine-Resistant HIV-1 in a Seroconverter From the SSAT 040 Trial Who Received the 300-mg Dose of Long-Acting Rilpivirine (TMC278LA).

The injectable long-acting formulation of rilpivirine (TMC278LA) is a promising preexposure prophylaxis (PrEP) candidate for prevention of human immunodeficiency virus type 1 (HIV-1) infection. We evaluated HIV-1 in plasma obtained from an unexpected seroconverter in the 300-mg arm of the SSAT040 TMC278LA pharmacokinetic study for rilpivirine (RPV) resistance. Infection with wild-type HIV-1 was confirmed on day 84 after TMC278LA injection, and the K101E mutation was detected on day 115. Plasma-derived HIV-1 clones containing K101E had 4-fold increased resistance to RPV and 4-8-fold increased cross-resistance to etravirine, nevirapine, and efavirenz compared with wild type HIV-1 plasma-derived clones from the same individual. This case is a unique instance of infection with wild-type HIV-1 and subsequent selection of resistant virus by persistent exposure to long-acting PrEP.

Dolutegravir and elvitegravir plasma concentrations following cessation of drug intake.

OBJECTIVES: To evaluate dolutegravir and elvitegravir/cobicistat pharmacokinetics in HIV-negative volunteers up to 10 days after drug cessation. METHODS: Healthy volunteers received 50 mg of dolutegravir once-daily for 10 days, then underwent a 9 day wash-out period, and then received elvitegravir/cobicistat as part of Stribild(®) (245 mg of tenofovir, 200 mg of emtricitabine, 150 mg of elvitegravir and 150 mg of cobicistat) for 10 days. Serial pharmacokinetic (PK) sampling occurred prior to the final dose of each course and at regular intervals for up to 216 h (10 days) after drug cessation. Concentrations were determined by LC-MS/MS, and PK parameters were illustrated as geometric mean and 90% CI. RESULTS: Seventeen volunteers completed the study. For dolutegravir, plasma terminal elimination t1/2 to the last measurable concentration (within 216 h) was longer than its t1/2 within the dosing interval (0-24 h): 14.3 h (12.9-15.7 h) versus 23.1 h (19.7-26.6 h); conversely, the terminal elimination t1/2 for elvitegravir was lower than its t1/2 within the dosing interval (0-24 h): 10.8 h (9.7-13.0 h) versus 5.2 h (4.7-6.1 h). Dolutegravir concentrations were above the protein-adjusted (PA) IC90 (64 ng/mL) in 100% of subjects after 36 and 48 h and in 94% after 60 and 72 h. All subjects had detectable dolutegravir concentrations at 96 h, a mean of 23.5% above the IC90. Elvitegravir concentrations were above the PA IC95 (45 ng/mL) in 100% of subjects at 24 h, 65% at 36 h but 0% after 48 h. CONCLUSIONS: Our data show marked differences in the elimination rates of dolutegravir and elvitegravir following treatment interruption, which is likely to impact the extent to which drug doses can be delayed or missed. They suggest that clinical differences may emerge in patients who have suboptimal adherence.

Plasma Tenofovir, Emtricitabine, and Rilpivirine and Intracellular Tenofovir Diphosphate and Emtricitabine Triphosphate Pharmacokinetics following Drug Intake Cessation.

Pharmacokinetic (PK) data describing a prolonged time course of antiretrovirals in plasma and peripheral blood mononuclear cells (PBMCs) are important for understanding and managing late or missed doses and to assess the appropriateness of compounds for preexposure prophylaxis (PrEP). This study aimed to evaluate the PK of coformulated tenofovir disoproxil fumarate (DF), emtricitabine, and rilpivirine in plasma and of the intracellular (IC) anabolites tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP) in healthy volunteers up to 9 days after drug cessation. Individuals received daily tenofovir DF-emtricitabine-rilpivirine (245/200/25 mg) for 14 days. Drug intake was stopped, and serial sampling occurred prior to the final dose and up to 216 h (9 days) after stopping drug intake. Concentrations were quantified and PK parameters calculated. Eighteen volunteers completed the study. The terminal elimination plasma half-lives for tenofovir and emtricitabine over 216 h (geometric mean [90% confidence interval]) were higher than those seen over 0 to 24 h (for tenofovir, 31 h [27 to 40 h] versus 13.3 h [12.5 to 15.1 h]; for emtricitabine, 41 h [36 to 54 h] versus 6.4 h (5.9 to 7.6 h]). Model-predicted IC half-lives (0 to 168 h) were 116 h (TFV-DP) and 37 h (FTC-TP). The plasma rilpivirine concentration at 216 h was 4.5 ng/ml (4.2 to 6.2 ng/ml), and half-lives over 0 to 216 h and 0 to 24 h were 47 h (41 to 59 h) and 35 h (28 to 46 h), respectively. These data contribute to our understanding of drug behavior following treatment interruption; however, adherence to therapy should be promoted. Validated plasma and IC target concentrations are necessary to allow interpretation with respect to sustained virus suppression or HIV prevention. (The trial was conducted in accordance with the Declaration of Helsinki [EudraCT 2012-002781-13].).

Long-acting rilpivirine for HIV prevention.

PURPOSE OF REVIEW: Long-acting injectable antiretroviral (ARV) formulations are being developed for the treatment and prevention of HIV infection. The purpose of this review is to summarize recent preclinical and clinical data on TMC278 (rilpivirine), a nonnucleoside reverse transcriptase inhibitor (NNRTI), that is being developed for both a treatment and prevention indication. RECENT FINDINGS: Long-acting rilpivirine has demonstrated efficacy in preventing HIV acquisition in a humanized mouse model and has been found to be well tolerated and acceptable in several Phase I clinical trials. Pharmacokinetic data from Phase I studies suggest that 1200 mg of long-acting rilpivirine administered every 8 weeks would be associated with plasma and tissue levels of rilpivirine anticipated to be necessary for preventing HIV infection. This regimen is being evaluated in the HPTN-076 Phase II expanded safety study that will enroll women in South Africa, Zimbabwe, and the USA. The HPTN-076 study requires a 4-week run in with oral rilpivirine (25 mg capsules) before receiving 1200 mg of rilpivirine. It is not yet certain whether oral dosing will remain a prerequisite in future trials or post licensure. SUMMARY: Long-acting rilpivirine shows promise as a candidate agent for HIV prevention. Preclinical efficacy has been demonstrated in a murine model. Phase I studies have shown good safety and efficacy, but breakthrough infection and resistance have been documented with lower doses of long-acting rilpivirine. Phase II development for a prevention indication is ongoing.

Effect of a modified saquinavir/ritonavir dosing regimen with lower dose lead-in phase on QTc interval, pharmacokinetics, antiviral activity and safety in treatment-naïve HIV-1-infected patients.

BACKGROUND: Saquinavir/ritonavir (1000/100 mg twice daily [BID]) is associated with dose- and exposure-dependent prolongation of the QT interval. The QT risk is considered higher during the first week of therapy, when saquinavir peak exposure has been observed. A modified regimen with a lower dose lead-in phase may reduce potential saquinavir-/ritonavir-induced QT prolongations. OBJECTIVE: To explore the effect of the modified saquinavir/ritonavir regimen on QT interval, pharmacokinetics, antiviral activity, and safety in treatment-naïve HIV-1-infected patients. METHODS: Twenty-three HIV-1-infected treatment-naïve patients received saquinavir/ritonavir 500/100 mg BID on days 1-7 and 1000/100 mg BID on days 8-14 in combination with two nucleoside reverse transcriptase inhibitors. The primary endpoint was mean maximum change from dense predose baseline in QT values corrected using Fridericia's formula (∆QTcFdense) across study days. Secondary endpoints included maximum change from time-matched baseline in QTcF, antiviral activity, pharmacokinetics, and safety over the 14 days. RESULTS: The mean maximum ∆QTcFdense was 3, 1, 7, 12, and 7 ms on days 3, 4, 7, 10, and 14, respectively. Across all study days, 2/21 patients had a maximum ∆QTcFdense ≥30 ms (on day 10); the highest mean ∆QTcFdense was <10 ms. During week 1, saquinavir exposure was highest on day 3 and lowest on day 7. All patients showed continuous declines in HIV-RNA; none experienced virologic breakthrough/rebound. The modified regimen was generally well tolerated. CONCLUSION: Treatment initiation with the modified saquinavir/ritonavir regimen in treatment-naïve HIV-1-infected patients reduced saquinavir exposure during week 1, potentially mitigating/reducing QT liability while suppressing HIV-RNA during the course of treatment.

The pharmacokinetic profile of raltegravir-containing antiretroviral therapy in HIV-infected individuals over 60 years of age.

BACKGROUND: Antiretroviral safety and efficacy and may differ in older versus younger HIV-infected patients. The objective of this study was to assess the pharmacokinetic (PK) profile in older HIV-infected subjects (>60 years) switching combination antiretroviral therapy (cART) to a raltegravir (RAL) containing regimen. METHODS: Nineteen HIV-infected patients over 60 years of age on effective cART (HIV-RNA < 50 copies/ml) were enrolled in this prospective 24-week study. On day 1, patients switched to tenofovir/emtricitabine (245/200 mg once daily) and RAL (400 mg twice daily). On day 28, intensive PK sampling was undertaken in a fasted state and RAL plasma concentrations determined. Neurocognitive function was assessed at baseline and week 24 using a neuropsychological battery. RAL PK parameters were compared to those of two younger historical HIV-infected control groups that received twice-daily RAL co-administered with darunavir/ritonavir (DRV/r) 800/100 once daily by nonlinear mixed effects modelling. RESULTS: In HIV-infected subjects over the age of 60 (mean ± SD age: 66 ± 3.4 years, n = 19) switching to a RAL containing regimen, we observed no safety concerns, no plasma virological rebounds, and no differences in RAL apparent oral clearance when compared to younger HIV-infected populations (mean ± SD age: 41 ± 9.2 years, n = 38) based on population pharmacokinetic analysis. After 24 weeks of study therapy a decline in cognitive function was observed [change in (SD) global score of (0.91 (1.3), P = 0.018]. CONCLUSIONS: No significant changes in RAL exposure associated with age were observed.

Switching safely: pharmacokinetics, efficacy and safety of switching efavirenz to maraviroc twice daily in patients on suppressive antiretroviral therapy.

BACKGROUND: CYP3A4 induction by efavirenz (EFV) persists after drug cessation; we assessed the pharmacokinetics (PK), efficacy and safety of maraviroc (MVC) administered to HIV-infected individuals switching from EFV-containing therapy. METHODS: Patients with R5-tropic virus and suppressed viral load on two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) plus EFV switched EFV to MVC 600 mg twice daily for 14 days, and then to MVC 300 mg twice daily. Following screening, three intensive PK visits were performed (sampling was pre-dose and 1, 2, 4, 6, 8 and 12 h post-dose): day 1 (VISIT 1, MVC 600 mg twice daily), day 14 (VISIT 2, steady-state MVC 600 mg twice daily) and day 28 post regimen switch (VISIT 3, steady-state MVC 300 mg twice daily); MVC trough concentration (Ctrough) was determined 3, 6 and 10 days following regimen switch and viral loads up to week 24. MVC PK parameters on visits 1 and 2 and MVC Ctrough on day 6 were compared to visit 3 (reference) via geometric mean ratios (GMR) and 95% CIs. RESULTS: Twelve males completed the study. MVC PK parameters at visit 1 versus visit 3 were: GMR and 95% CI 12-h area under the curve (AUC0-12) 1.25 (1.00, 1.58); Cmax 1.64 (1.16, 2.31); Ctrough 0.61 (0.46, 0.80). Visit 2 MVC PK parameters were significantly higher than visit 3: GMR and 95% CI AUC0-12 2.31 (1.84, 2.90); Cmax 2.42 (1.87, 3.12); Ctrough 2.25 (1.74, 2.91). MVC was well tolerated with no grade 3/4 adverse events; all subjects maintained viral suppression to the end of the study. CONCLUSIONS: The EFV induction effect necessitated increased MVC dose to 600 mg twice daily following switch and persisted for approximately one week after EFV cessation. This is less than the 2-week induction observed when switching EFV to etravirine and highlights the importance of studying different tail interactions. Higher dose MVC was well tolerated. All measured MVC Ctrough concentrations exceeded wild-type 90% inhibitory concentration.

Quantification of rilpivirine in human plasma, cervicovaginal fluid, rectal fluid and genital/rectal mucosal tissues using liquid chromatography-tandem mass spectrometry.

BACKGROUND: A sensitive, specific and robust liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of rilpivirine in human plasma, genital/rectal biofluids and mucosal tissues. METHODS: Plasma and tissue samples were extracted using protein precipitation (acetonitrile/water; 5:1 v/v), and genital/rectal biofluids absorbed onto ophthalmic swabs were extracted using liquid-liquid extraction (hexane/ethyl acetate; 80:20 v/v). A stable isotope-labeled internal standard ((13)C-d4-RPV) was used, and the assay was validated over a concentration range of 0.5-400 ng/ml. CONCLUSION: Inter- and intra-assay precision and accuracy met the acceptance as per US FDA bioanalytical guidelines. The validated assay has been used for the determination of rilpivirine concentrations in these matrices as part of an exploratory pharmacokinetic study investigating the suitability of a long-acting formulation of rilpivirine for pre-exposure prophylaxis.

Pharmacology lessons from chemoprophylaxis studies.

Pharmacological studies in the context of preexposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) are fundamental to inform on different drug pharmacokinetics, pharmacodynamics, and pharmacogenetics in view of the absence of easily measurable surrogate markers of efficacy. Although the combination of tenofovir and emtricitabine is the only PrEP agent that was studied and showed efficacy in preventing HIV transmission, prospective randomized clinical trials have reported varying efficacy due to poor adherence to the drug. Importantly, this could be overcome by the introduction of long-acting injectable PrEP agents, which may be administered monthly and ensure optimal and prolonged drug exposure in HIV target tissues. Notably, clinical pharmacology studies play a central role in interpreting drug concentration-responses and optimal drug exposure achievement.

Pharmacokinetics of the co-administration of boceprevir and St John's wort to male and female healthy volunteers.

BACKGROUND: St John's wort (SJW; Hypericum perforatum) induces CYP3A4 that is involved in the metabolism of the hepatitis C virus (HCV) protease inhibitor boceprevir. Reduced boceprevir exposure and efficacy would contribute to therapeutic failure and increase the risk for resistance development. Boceprevir is co-administered with interferon/ribavirin, and depression has been described frequently in patients undergoing HCV treatment. Patients may purchase over-the-counter herbals to manage depression, and knowing the interaction between SJW and boceprevir is desirable. METHODS: This Phase I, open-label, three-period, cross-over pharmacokinetic study enrolled healthy males and females who, following consent and screening procedures, were randomized to receive SJW on days 1-14, SJW plus boceprevir (SJW on days 22-35 and together on days 31-35) and boceprevir on days 52-56, separated by 7 day washout periods, or the same treatment in the opposite order. Pharmacokinetic sampling was performed at the end of each phase. RESULTS: Seventeen (11 female) subjects completed the study and no serious adverse events were reported. Geometric mean ratios (GMRs) and 90% CIs for boceprevir (with SJW versus alone) AUC(0-8), C(max) and C8 were 0.91 (0.87-0.96), 0.94 (0.82-1.07) and 1.00 (0.79-1.27), respectively. GMRs and 90% CIs for hypericin, the active component of SJW, (with boceprevir versus alone) AUC(0-8), C(max) and C(8) were 1.23 (1.10-1.38), 1.32 (1.16-1.52) and 1.37 (1.19-1.58), respectively. CONCLUSIONS: SJW did not have a clinically significant effect on boceprevir plasma concentrations (or those of its metabolite), suggesting that SJW and boceprevir can be safely co-administered.

New approaches to antiretroviral drug delivery: challenges and opportunities associated with the use of long-acting injectable agents.

Research on improved treatment of HIV infection and pre-exposure prophylaxis continues. Poor adherence to treatment is the critical risk factor for virological failure and resistance development, and long-acting formulations of anti-HIV medications that need only infrequent dosing may facilitate long-term therapeutic responses. Importantly, long-acting formulations of therapeutic agents have been used to avoid missing doses or treatment fatigue to prescribed lifelong medications in a number of different medical fields, with demonstrable success. However, such formulations are associated with challenges, such as the prolongation of adverse events with the persistence of drug concentrations and concerns over the development of resistance as a result of selective pressure as drug concentrations decline. Furthermore, long-acting injectable formulations of antiretroviral (ARV) agents with infrequent dosing may be advantageous over daily oral drug intake to prevent transmission of HIV. However, the knowledge on protective drug concentrations and frequency of dosing is poor to date and implementation globally is challenging. Importantly, if nanoformulations of ARVs requiring lower drug doses become available globally, the potential for treatment cost reductions is high, as, especially in resource-limited settings, the active pharmaceutical ingredient accounts for the greater proportion of the total cost of the medicine. In conclusion, different long-acting ARVs are being studied in phase I/II for both the treatment and prevention of HIV infection, and research on administering these agents in combination has started.

Non-immunogenicity of overlapping gag peptides pulsed on autologous cells after vaccination of HIV infected individuals.

BACKGROUND: HIV Gag-specific CD4+ and CD8+ T-cell responses are important for HIV immune control. Pulsing overlapping Gag peptides on autologous lymphocytes (OPAL) has proven immunogenic and effective in reducing viral loads in multiple pigtail macaque studies, warranting clinical evaluation. METHODOLOGY: We performed a phase I, single centre, placebo-controlled, double-blinded and dose-escalating study to evaluate the safety and preliminary immunogenicity of a novel therapeutic vaccine approach 'OPAL-HIV-Gag(c)'. This vaccine is comprised of 120 15mer peptides, overlapping by 11 amino acids, spanning the HIV Gag C clade sequence proteome, pulsed on white blood cells enriched from whole blood using a closed system, followed by intravenous reinfusion. Patients with undetectable HIV viral loads (<50 copies/ml plasma) on HAART received four administrations at week 0, 4, 8 and 12, and were followed up for 12 weeks post-treatment. Twenty-three people were enrolled in four groups: 12 mg (n = 6), 24 mg (n = 7), 48 mg (n = 2) or matching placebo (n = 8) with 18 immunologically evaluable. T-cell immunogenicity was assessed by IFNγ ELIspot and intracellular cytokine staining (ICS). RESULTS: The OPAL-HIV-Gag(c) peptides were antigenic in vitro in 17/17 subjects. After vaccination with OPAL-HIV-Gag(c), 1/6 subjects at 12 mg and 1/6 subjects at 24 mg dose groups had a 2- and 3-fold increase in ELIspot magnitudes from baseline, respectively, of Gag-specific CD8+ T-cells at week 14, compared to 0/6 subjects in the placebo group. No Gag-specific CD4+ T-cell responses or overall change in Rev, Nef, Tat and CMV specific responses were detected. Marked, transient and self-limiting lymphopenia was observed immediately post-vaccination (4 hours) in OPAL-HIV-Gag(c) but not in placebo recipients, with median fall from 1.72 to 0.67 million lymphocytes/mL for active groups (P<0.001), compared to post-placebo from 1.70 to 1.56 lymphocytes/ml (P = 0.16). CONCLUSION/SIGNIFICANCE: Despite strong immunogenicity observed in several Macaca nemestrina studies using this approach, OPAL-HIV-Gag(c) was not significantly immunogenic in humans and improved methods of generating high-frequency Gag-specific T-cell responses are required. NAME OF REGISTRY: ClinicalTrials.gov, Registry number: NCT01123915, URL trial registry database: http://www.clinicaltrials.gov/ct2/results?term=OPAL-HIV-1001&Search=Search.

Safety, immunogenicity and efficacy assessment of HIV immunotherapy in a multi-centre, double-blind, randomised, Placebo-controlled Phase Ib human trial.

BACKGROUND: Combination antiretroviral therapy (cART) is the main therapeutic management tool for HIV/AIDS. Despite its success in controlling viral load and disease progression, cART is expensive, associated with a range of significant side effects and depends for its efficacy on the patient's life-long commitment to high levels of treatment adherence. Immunotherapeutic agents can provide potential solutions to these shortcomings. Here we describe a Phase Ib trial of HIV-v, a synthetic immunotherapy that elicits T- and B-cell effector responses against HIV infected cells. METHODS: Fifty-nine cART-naive HIV-infected males aged 18-50 years with viral load of 5000-500,000 copies/ml and CD4 counts >350/µl were recruited for this multi-centre, randomised, double blind study. Volunteers received one low (250 µg) or high (500 µg) dose of HIV-v, either alone or adjuvanted (ISA-51). Safety, immunogenicity, CD4 count and viral load were monitored over 168 Days. RESULTS: HIV-v was well tolerated and the adjuvanted formulations elicited IgG responses in up to 75% of volunteers. The high adjuvanted dose also elicited cellular responses in 45% of tested volunteers. In these responding subjects viral loads were reduced by over 1 log (p=0.04) compared to Placebo and non-responders. No changes in CD4 count were observed. CONCLUSIONS: HIV-v is safe and can elicit T- and B-cell responses in ART-naive HIV patients that significantly reduce viral load. Improved dosing regimens and further research on long term efficacy are required, but HIV-v appears to have potential as an immunotherapeutic anti-viral agent. Trial registered as EudraCT-2009-010593-37 (ClinicalTrials.gov Identifier: NCT01071031).

A randomised, placebo-controlled, first-in-human study of a novel clade C therapeutic peptide vaccine administered ex vivo to autologous white blood cells in HIV infected individuals.

BACKGROUND: Preclinical studies of overlapping 15mer peptides, spanning SIV, SHIV or HIV, pulsed on autologous PBMC ex vivo have demonstrated high level, virus-specific T cell responses and viral suppression in non-human primates (NHP). Opal-HIV-Gag(c) consists of 120 synthetic 15mer peptides spanning Clade C, consensus Gag, manufactured to current good manufacturing practice; having been evaluated in a good laboratory practice toxicology study in Macaca mulatta. We evaluated the safety and preliminary immunogenicity of such peptides administered intravenously after short-duration ex vivo incubation, to HIV-positive adults on suppressive antiretroviral therapy. METHODS AND FINDINGS: A first-in-human, placebo-controlled, double-blind, dose escalation study was conducted. Twenty-three patients with virus suppressed by antiretroviral therapy were enrolled in four groups 12 mg (n = 6), 24 mg (n = 6), 48 mg (n = 2) or matching placebo (n = 8). Treatment was administered intravenously after bedside enrichment of 120 mL whole blood for white cells using a closed system (Sepax S-100 device), with ex vivo peptide admixture (or diluent alone) and 37°C incubation for one hour prior to reinfusion. Patients received 4 administrations at monthly intervals followed by a 12-week observation post-treatment. Opal-HIV-Gag(c) was reasonably tolerated at doses of 12 and 24 mg. There was an increased incidence of temporally associated pyrexia, chills, and transient/self-limiting lymphopenia in Opal-HIV-Gag(c) recipients compared to placebo. The study was terminated early, after two patients were recruited to the 48 mg cohort; a serious adverse event of hypotension, tachycardia secondary to diarrhoea occurred following a single product administration. An infectious cause for the event could not be identified, leaving the possibility of immunologically mediated product reaction. CONCLUSIONS: A serious, potentially life-threatening event of hypotension led to early, precautionary termination of the study. In the absence of a clearly defined mechanism or ability to predict such occurrence, further development of Opal-HIV-Gag(c) will not be undertaken in the current form. REGISTRATION: ClinicalTrials.gov NCT01123915; EudraCT: 2008-005142-23.