Davis, Davis, United States SHIV Infection and Drug Transporters Influence Brain Tissue Concentrations of Efavirenz Nithya Srinivas1, John Fallon1, Craig Sykes1, Nicole White1, Amanda Schauer1, Lou Adamson2, Michelle Matthews1, Paul Luciw2, Phil Smith1, Angela DM Kashuba1 1University of North Carolina at Chapel Hill, Chapel Hill, United States, 2University of California, Davis, Davis, United States

Background HIV-associated neurocognitive disorder (HAND) 1 Background HIV-associated neurocognitive disorder (HAND) HAD – HIV-associated Dementia Neurocognitive Impairment MND – Mild Neurocognitive Disorder ANI – Asymptomatic Neurocognitive Impairment Christine M Marra Antiviral Therapy 2015 Mar 17. doi: 10.3851/IMP2951

Why Does HAND Persist Despite Therapy? Background Why Does HAND Persist Despite Therapy? 2 Irreversible CNS injury caused before initiation of treatment Inadequate control of persistent CNS infection Neurotoxicity due to antiretroviral medication Letendre S., Top Antivir Med. 2011 Nov;19(4):137-42

Background Measurement of Antiretroviral PK in the CNS 3 Antiretrovirals (ARVs) are measured in CSF by lumbar puncture BCRP P-gp ARV concentrations measured in human brain Bumpus et. Al. Conference on Retroviruses and Opportunistic Infection, 2015, Poster 436 Adapted from Hammarlund-Udenaes et al., Pharm Res 25: 1737, 2008

Aim 5 Measure the concentration of 6 ARVs in the brain tissue and CSF of uninfected and SHIV infected rhesus macaques Measure the concentration of BCRP and P-gp transporter proteins by quantitative targeted absolute proteomics (QTAP) in the brain tissue of the above cohort Determine the effect of SHIV infection and drug transporters on brain tissue concentrations of ARVs

Methods 6 Antiretroviral Drugs and Transporter Interactions Parts of Brain

Methods Animals – Rhesus macaques 7 Animals – Rhesus macaques Animals were dosed for 10 days Measurement of drug concentration – LCMS/MS ARVs were measured in the CSF (LLOQ=0.5 ng/mL) and 4 parts of the brain tissue (LLOQ of homogenate ranged from 0.002-0.01 ng/mL) Difference in drug concentrations were determined by Kruskal-Wallis test Measurement of drug transporters - QTAP Brain tissue samples were homogenized and protein was extracted and trypsynized. Peptides for BCRP and P-gp were quantified using radio labelled ligands by LCMS Difference in transporter concentrations were determined by a t-test Uninfected (n=6) Infected (n=6) tenofovir/emtricitabine/maraviroc/atazanavir (n=3) tenofovir/emtricitabine/efavirenz/raltegravir (n=3)

Results 8 No difference in ARV concentrations between different parts of the brain

Results 9 p<0.005 p=0.01 p=0.18 p<0.01 p=0.14 p=0.2 p<0.05

Correlation between ARV PK in CSF and brain tissue 10 r2 = 0.743 p < 0.001 r2 = 0.453 p = 0.016 r2 = 0.939 p < 0.001 r2 = 0.041 p = 0.701 r2 = 0.753 p = 0.025 r2 = 0.966 p < 0.001

Effect of SHIV on efflux transporter concentrations 11 p = 0.02 p = 0.06

Relationship between BCRP and ARV concentration 12 r2 = 0.14 p = 0.23 r2 = 0.00 p = 0.97 r2 = 0.33 r2 = 0.06 p = 0.45 r2 = 0.55 p = 0.09 r2 = 0.02 p = 0.80

Limitations 13 Small sample size (n=6 for efavirenz, raltegravir, maraviroc and atazanavir) Exposure of drug in brain over 24h was not measured, and may be a more accurate measure than trough concentration Only efflux transporters were measured in this analysis, no effect of influx transporters or drug-metabolizing enzymes

Summary 14 Brain tissue concentrations were shown to be significantly higher than CSF for efavirenz, emtricitabine and tenofovir CSF concentrations were only predictive of brain tissue concentrations for efavirenz Brain tissue concentrations of efavirenz were 4-fold higher in uninfected animals compared to infected animals BCRP protein concentrations were 2 fold lower in uninfected animals than in infected. No differences seen for P-gp protein Trend noted between increasing concentrations of BCRP protein and lower efavirenz concentration in brain tissue

Total vs. free concentrations of efavirenz in brain tissue Conclusions 15 Lower concentrations of efavirenz in brain tissue occurs with SHIV infection Upregulation of BCRP transporter protein may contribute to this effect For HIV-patients on efavirenz based therapies, perhaps low drug concentration in brain tissue contributes to HAND persistence Total vs. free concentrations of efavirenz in brain tissue IC90 IC50

Acknowledgements 16 CFAR CPAC Lab Dr. Angela Kashuba Craig Sykes Nicole White Amanda Schauer Tissue Pathology Michelle Matthews Smith Lab Dr. John Fallon Dr. Phil Smith Luciw Lab Lou Adamson Dr. Paul Luciw Committee Members Dr. Kim Brouwer Dr. Amanda Corbett Dr. Alan Forrest Dr. Kevin Robertson Dr. Elena Batrakova Funding Sources Royster Society of Fellows AFPE Predoctoral fellowship UNC CFAR P30 AI50410 R01-GM66940 and R01-GM096967 THINC P01 MH094177

QUESTIONS? nithyas@email.unc.edu