Lucy Garvey

A phase Iv, double-blind, multicentre, randomized, placebo-controlled, pilot study to assess the feasibility of switching individuals receiving efavirenz with continuing central nervous system adverse events to etravirine

Background:Two nucleoside reverse transcriptase inhibitors (NRTIs) and efavirenz (EFV) is a recommended initial regimen for HIV-1. Most EFV-related central nervous system (CNS) toxicity resolves early though symptoms may persist; we studied switching to etravirine (ETR) in these individuals. Methods:A randomized, double-blind trial in patients with viral suppression but ongoing CNS adverse events after more than 12 weeks EFV. Patients received 2NRTI/EFV/ETR-placebo (delayed switch) or 2NRTI/ETR/EFV-placebo (immediate switch) for 12 weeks followed by 12-week open-label phase (2NRTI/ETR). Primary end-point was percentage with G2-4 CNS adverse events at 12 weeks. Results:Thirty-eight men; 20/18 were randomized to immediate switch/delayed switch; median CD4 was 444/498 cells/μl, respectively. Baseline CNS adverse events were similar. Nineteen immediate switch patients completed follow-up (one lost to follow-up) and 13 on delayed switch (two lost to follow-up, two withdrawn consent, one adverse event). Immediate switch G2-4 CNS adverse event: 90% at baseline, 60% at week 12 (P = 0.041). Delayed switch G2-4 CNS adverse event: 88.9% at baseline, 81.3% at week 12 (P = ns). Combined (both arms) percentage decline in G2-4 CNS adverse event after 12 weeks of ETR was significant for overall adverse events, insomnia, abnormal dreams and nervousness (P = 0.009, 0.016, 0.001, and 0.046, respectively). All participants on study maintained HIV-RNA below 50 and median week 24 CD4 was 593 and 607 cells/μl on immediate switch and delayed switch. Two participants experienced new G3-4 adverse events [delayed switch: G3 flatulence on EFV); immediate switch: G4 viral URTI on ETR (SAE)]. Conclusion:Switching EFV to ETR led to a significant reduction in overall G2-4 CNS adverse events, including insomnia, abnormal dreams and nervousness as individual adverse event. Lack of improvement for some events suggests other causative factors.

HIV-associated central nervous system diseases in the recent combination antiretroviral therapy era

Background and purpose:  Data describing the incidence and survival of HIV‐related central nervous system diseases (CNS‐D) in recent years are sparse.

Increased microglia activation in neurologically asymptomatic HIV-infected patients receiving effective ART

Background:Neuroinflammation plays an important role in HIV-associated neurological disorders; however, its role prior to the onset of symptomatic disease is unclear. We imaged microglial activation, the hallmark of neuroinflammation, in asymptomatic HIV-infected patients on effective combination ART. Methods:Seven neurologically and cognitively asymptomatic adults with chronic HIV-infection and nine healthy volunteers were investigated with [11C]-PK11195 PET, a marker of translocator protein (TSPO) expressed by activated microglia. In the HIV-infected patients, cognitive speed, accuracy and executive function were also assessed. Between-group differences in [11C]-PK11195 binding potential were localized throughout the brain with statistical parametric mapping (SPM) and associations between levels of [11C]-PK11195 binding and cognitive performance were interrogated using linear regression modelling. Results:In HIV-infected patients, Statistical parametric mapping detected clusters of significantly increased [11C]-PK11195 binding in corpus callosum (P = 0.001), anterior cingulate (P = 0.001), posterior cingulate (P = 0.008) and temporal (P = 0.026) and frontal (P = 0.038) areas. Cognitive functions were intact in the HIV group, however, a significant association between greater [11C]-PK11195 binding and poorer executive function performance was observed in the anterior cingulate (P = 0.031), corpus callosum and posterior cingulate (P = 0.001). Conclusion:Despite effective control of HIV infection, neuroinflammation, as evidenced by the presence of focal cortical areas of activated microglia, occurs in asymptomatic HIV-infected patients and levels correlate with poorer executive performance. Further studies are needed to establish whether detection of activated microglia in HIV-infected patients represents a marker of future neurocognitive decline.

Factors associated with cerebrospinal fluid HIV RNA in HIV infected subjects undergoing lumbar puncture examination in a clinical setting

BACKGROUND Cerebrospinal fluid (CSF) HIV RNA load may be associated with central nervous system (CNS) disease in HIV infected subjects. We investigated parameters associated with CSF HIV RNA within a large clinical cohort. METHODS All HIV infected subjects undergoing CSF examination including assessment of CSF HIV RNA at St. Marys Hospital, London, UK between January 2008 and October 2010 were included. Parameters associated with a detectable CSF HIV RNA load were assessed using linear regression modelling. CSF viral escape was defined as CSF RNA >0.5 log(10) copies/mL greater than plasma HIV RNA and >200 copies/mL where plasma HIV RNA <50 copies/mL. RESULTS Of 142 subjects, 99 were receiving antiretroviral therapy (ART). Plasma HIV RNA was <50 copies/mL in 69 subjects. CSF examination was performed for investigation of presumed HIV encephalopathy (IxHE, n = 57), other CNS diseases considered HIV related (n = 39), syphilis (n = 20) and CNS presentations not considered HIV related (n = 26). CSF viral escape was present in 30/142 (21%) subjects overall and in 9/69 (13%) of those on ART with undetectable plasma HIV RNA. Overall, plasma HIV RNA load was significantly associated with detectable CSF HIV RNA (p ≤ 0.001). In subjects with plasma HIV RNA <50 copies/mL, only CNS penetration effectiveness (CPE, 2008) score of <2 was significantly associated with detectable CSF HIV RNA (p = 0.044). In patients undergoing LP for IxHE both plasma HIV RNA and CPE scores were independently associated with detectable CSF HIV RNA (p = 0.019 & 0.003 respectively) which was not observed in subjects undergoing CSF examination for other medical reasons. CONCLUSIONS In a clinical setting, CSF viral escape is observed frequently in 21% of subjects and is associated with different parameters depending on the clinical scenario.

Antiretroviral therapy CNS penetration and HIV-1–associated CNS disease

Objective: The impact of different antiretroviral agents on the risk of developing or surviving CNS disease remains unknown. The aim of this study was to investigate whether using antiretroviral regimens with higher CNS penetration effectiveness (CPE) scores was associated with reduced incidence of CNS disease and improved survival in the UK Collaborative HIV Cohort (CHIC) Study. Methods: Adults without previous CNS disease, who commenced combination antiretroviral therapy (cART) between 1996 and 2008, were included (n = 22,356). Initial and most recent cART CPE scores were calculated. CNS diseases were HIV encephalopathy (HIVe), progressive multifocal leukoencephalopathy (PML), cerebral toxoplasmosis (TOXO), and cryptococcal meningitis (CRYPTO). Incidence rates and overall survival were stratified by CPE score. A multivariable Poisson regression model was used to identify independent associations. Results: The median (interquartile range) CPE score for initial cART regimen increased from 7 (5–8) in 1996–1997 to 9 (8–10) in 2000–2001 and subsequently declined to 6 (7–8) in 2006–2008. Differences in gender, HIV acquisition risk group, and ethnicity existed between CPE score strata. A total of 251 subjects were diagnosed with a CNS disease (HIVe 80; TOXO 59; CRYPTO 56; PML 54). CNS diseases occurred more frequently in subjects prescribed regimens with CPE scores ≤4, and less frequently in those with scores ≥10; however, these differences were nonsignificant. Initial and most recent cART CPE scores ≤4 were independently associated with increased risk of death. Conclusion: Clinical status at time of commencing cART influences antiretroviral selection and CPE score. This information should be considered when utilizing CPE scores for retrospective analyses.

Rilpivirine: a novel non-nucleoside reverse transcriptase inhibitor

Combination antiretroviral therapy has transformed the prognosis and life expectancy of HIV-1 infected individuals in resource-rich settings. British guidelines currently recommend the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz as part of first-line treatment in therapy-naive HIV-1 infected individuals. However, efavirenz is limited by its low genetic barrier to the development of resistance, together with its potential for CNS toxicities. To overcome these obstacles, several ‘next-generation’ NNRTIs are in various stages of clinical development. Here, we review the journey of rilpivirine (also known as TMC278, Tibotec), from the discovery of the chemical compound, through successful Phase I and II development, to its current position of being studied in international Phase III trials for the treatment of therapy-naive HIV-1 infected subjects using a 25 mg daily dose. Pharmacokinetic findings and food and drug interactions are discussed, together with safety profile. Rilpivirine has demonstrated high antiviral activity (including against NNRTI-resistant isolates) in vitro, with similar rates of virological suppression in therapy-naive individuals at 96 weeks when compared to efavirenz. Rilpivirine seems to be well tolerated with less CNS disturbance than efavirenz, and has non-teratogenic potential; however, unfavorable interactions with acid suppressant medications will require heightened vigilance when rilpivirine is used in widespread clinical practice.

Correlations between Computerized Battery Testing and a Memory Questionnaire for Identification of Neurocognitive Impairment in HIV Type 1-Infected Subjects on Stable Antiretroviral Therapy

Neurocognitive impairment (NCI) remains prevalent in the highly active antiretroviral therapy (HAART) era. Memory function is commonly affected. There is a need for a rapid, but sensitive screening tool. This study compares the Prospective and Retrospective Memory Questionnaire (PRMQ) and a computerised battery cognitive assessment to establish if the questionnaire has potential as a rapid screening tool for HIV-associated NCI. Neurologically asymptomatic patients with an undetectable HIV viral load on stable HAART were eligible to participate. Asymptomatic NCI (aNCI) was defined as a performance score more than 1SD below the normative mean in at least two domains of the computerised test. Memory impairment (MI) was defined as a t-score more than 1 SD below the normative mean using the PRMQ. Forty-five subjects participated. The mean age was 48 years (SD 11), the mean CD4 count was 546 cells/mul (SD 271), and 84% were male. Of subjects, 14/45 (24%) had NCI and 15/45 (33%) had MI. Two subjects had both types of impairment. No significant association was found between the presence of aNCI and MI (p = 0.229, r = 0.18, 95% CI -1.2, 0.23). aNCI was statistically significantly associated with younger age (p = 0.38, r = 0.31, 95% CI -0.02, 0.001). MI was statistically significantly associated with the set-shifting cognitive domain of the computerized battery (p = 0.04, r = 0.326) and time elapsed since HIV diagnosis (p = 0.035, r = 0.316). High rates of asymptomatic NCI were observed in this cohort, especially in younger individuals. The memory questionnaire did not reliably identify HIV-associated NCI other than executive function deficits and based on our data should therefore not be used as a rapid screening tool for this purpose.

Does acute hepatitis C infection affect the central nervous system in HIV-1 infected individuals?

Summary.  Central nervous system (CNS) manifestations of chronic hepatitis C virus (HCV) and chronic human immune deficiency virus‐1 (HIV‐1) infections have been reported, but the impact of acute HCV infection on the CNS is unknown. A total of 10 individuals with chronic stable HIV‐1 with documented acute HCV (HCV‐RNA polymerase chain reaction positive and HCV antibody negative, group 1) underwent cerebral proton magnetic resonance spectroscopy (MRS) using acquisition parameters to quantify myo‐inositol/creatine (mI/Cr) ratio in the right basal ganglia (RBG). Two matched control groups also underwent MRS; group 2: ten with chronic HIV‐1 and no evidence of HCV, and group 3: ten with no evidence of HIV or HCV. Subjects also underwent computerized neurocognitive assessments (CogState™). RBG mI/Cr ratio in group 1 (acute HCV in a background of HIV) was significantly lower than that in groups 2 and 3 [2.90 (±0.7) vs 3.34 (±0.4) and 3.43 (±0.4), mean (SD) for group 1 vs 2 and 3 respectively, P = 0.049], with 50% of subjects in group 1 having a mI/Cr ratio below the lowest observed ratio in either of the other groups. On neurocognitive testing, significant defects in the monitoring domain were observed in group‐1, compared with matched controls (P = 0.021). Acute HCV in HIV‐1 infected subjects is associated with CNS involvement. Clinicians should be vigilant of early CNS involvement when assessing subjects with acute HCV.

Acute HCV/HIV Coinfection Is Associated with Cognitive Dysfunction and Cerebral Metabolite Disturbance, but Not Increased Microglial Cell Activation

Background Microglial cell activation and cerebral function impairment are described in both chronic hepatitis C viral (HCV) and Human-Immune-Deficiency viral (HIV) infections. The aim of this study was to investigate the effect of acute HCV infection upon cerebral function and microglial cell activation in HIV-infected individuals. Methods A case-control study was conducted. Subjects with acute HCV and chronic HIV coinfection (aHCV) were compared to matched controls with chronic HIV monoinfection (HIVmono). aHCV was defined as a new positive plasma HCV RNA within 12 months of a negative RNA test. Subjects underwent neuro-cognitive testing (NCT), cerebral proton magnetic resonance spectroscopy (1H-MRS) and positron emission tomography (PET) using a 11C-radiolabeled ligand (PK11195), which is highly specific for translocator protein 18 kDA receptors on activated microglial cells. Differences between cases and controls were assessed using linear regression modelling. Results Twenty-four aHCV cases completed NCT and 1H-MRS, 8 underwent PET. Of 57 HIVmono controls completing NCT, 12 underwent 1H-MRS and 8 PET. Subjects with aHCV demonstrated on NCT, significantly poorer executive function (mean (SD) error rate 26.50(17.87) versus 19.09(8.12), p = 0.001) and on 1H-MRS increased myo-inositol/creatine ratios (mI/Cr, a marker of cerebral inflammation) in the basal ganglia (ratio of 0.71(0.22) versus 0.55(0.23), p = 0.03), compared to subjects with HIVmono. On PET imaging, no difference in 11C-PK11195 binding potential (BP) was observed between study groups (p>0.10 all cerebral locations), however lower BPs were associated with combination antiretroviral therapy (cART) use in the parietal (p = 0.01) and frontal (p = 0.03) cerebral locations. Discussion Poorer cognitive performance and disturbance of cerebral metabolites are observed in subjects with aHC,V compared to subjects with HIVmono. Higher 11C-PK11195 BP was not observed in subjects with aHCV, but was observed in subjects not on cART.

CNS effects of a CCR5 inhibitor in HIV-infected subjects: a pharmacokinetic and cerebral metabolite study

BACKGROUND We conducted a pharmacokinetic and in vivo cerebral (1)H magnetic resonance spectroscopy ((1)H-MRS) study to assess CSF exposure and cerebral metabolite ratios (CMRs) following maraviroc intensification. METHODS HIV-infected neurologically asymptomatic adults receiving tenofovir, emtricitabine and lopinavir/ritonavir with plasma HIV RNA <50 copies/mL were eligible and received intensified therapy with 150 mg of maraviroc twice daily. (1)H-MRS was performed in several cerebral locations, including the right basal ganglia (RBG), to assess CMRs, including N-acetyl aspartate/creatine (NAA/Cr), at baseline and after 14 days. Subsequently, on day 15, blood samples were obtained to determine plasma concentrations of maraviroc pre-dose (C(trough)) and then paired blood and CSF samples were collected at 4 or 6 h post-dose. Associations between maraviroc exposure, clinical parameters and changes to CMRs were evaluated. TRIAL REGISTRY ClinicalTrials.gov (http://clinicaltrials.gov/ct2/show/NCT00982878). RESULTS Twelve subjects (75% male) participated with a mean (SD) CD4+ cell count of 503 (199) cells/μL. Mean (SD) maraviroc plasma concentrations at pre-dose, 4 h post-dose and 6 h post-dose were 337 (74), 842 (174) and 485 (100) ng/mL and CSF concentrations at 4 h post-dose and 6 h post-dose were 7.5 (1.3) and 5.1 (1.2) ng/mL. The mean maraviroc CSF : plasma ratio (range) was 1.01% (0.57%-1.61%). An increase of 14.8% was observed for the RBG NAA/Cr ratio, which was significantly associated with higher maraviroc plasma C(trough) (P = 0.05, r = 0.61), but not CSF concentration (P = 0.16, r = 0.46). CONCLUSIONS After 14 days of maraviroc intensification, small increases in cerebral metabolite markers of neuronal integrity (NAA/Cr ratios) were observed and are associated with maraviroc plasma C(trough).