1 Antiretroviral Regimen and Pharmacogenetic Determinants of Tenofovir-associated Change in Creatinine Clearance in ACTG Protocol A5142 (NWCS 291) Miguel Goicoechea, Yu Zheng, Michael Hughes, Sharon Riddler, Michael Neely, David Haas, Stan Louie and Richard Haubrich 21, July 2010

2 Background ●Phase 3 trials of Tenofovir (903 & 934) 1 ■EFV-based regimens for 144 weeks  No difference in CrCl changes between arms ●Case reports of Fanconi 2 ■Majority (83%) received TDF in PI-based regimens 3 ●Retrospective studies with greater CrCl declines with PI+TDF 4,5 ■Biphasic decline in CrCl 1 Gallant JAMA 2004; 2 Verhelst Am J Kidney Dis 2002; 3 Gupta AIDS Patient Care STDs 2008; 4 Goicoechea JID 2008; 5 Gallant AIDS 2009;

3 Renal clearance of tenofovir TFV MRP-4 OAT-1 & 3 MRP-2 PI/r TFV 80%20%

4 Objectives - Hypothesis ●(Primary) Regimen type and change in CrCl over 96 weeks ■ LPV/r + TDF regimens will be associated with greater declines in CrCl. ●Tenofovir plasma concentration and CrCl over 96 weeks ■ Higher tenofovir concentrations (weeks 4-16) will be associated with greater declines in CrCl. ●Polymorphisms in drug transporters and CrCl over 96 weeks ■ SNPs associated with increased influx (i.e. OAT-1) or decreased efflux (i.e. Pgp, MRP-2 and MRP-4) transporter expression/ function will be associated with greater CrCl decline.

5 Study Design of A5142 ARV-naïve HIV RNA >2,000 c/mL Any CD4 count 96 weeks Multicenter Randomized Open-label Screening LPV/r BID + EFV QD EFV 600 mg QD + 3TC + d4T XR or TDF or ZDV LPV/r 533/133 mg BID + EFV 600 mg QD LPV/r BID + 3TC + d4T XR or TDF or ZDV N  250/arm Riddler SA, Haubrich R et al., NEJM 2008 In A5142 renal events were rare: 9 subjects with grade 2 or less serum creatinine increase No TDF treatment discontinuations due to renal toxicity concerns

6 Four treatment groups: ●TDF with (or without) a ‘pharmacologic inhibitor’ ■LPV/r + TDF/3TC ■EFV + TDF/3TC * a priori main comparison ●Nucleoside-containing (Non-TDF) ■LPV/r or EFV + 2 NRTIs ●Nucleoside-sparing ■LPV/r + EFV NWCS Study Design

7 Methods ●Inclusion criteria: ■Subjects on randomized regimen until at least week 48 ■Stored serum at BL & w48 ●Estimated creatinine clearance (CrCl) ■Bun, Cr, albumin (BL and weeks 24, 48, 72 and 96) ■Cockcroft-Gault (ml/min) & MDRD (ml/min/1.73 m 2 ) ●Tenofovir exposure ■Plasma tenofovir (weeks 4, 12, 16) ●Single nucleoside polymorphisms ■ABCB1 (P-gp), ABCC2 (MRP-2), ABBC4 (MRP-4), SLC22A6 (OAT-1)

8 Baseline Characteristics No significant differences between treatment groups

9 Regimen type – Mean change and 95% CI

10 Regimen type and change in CrCL (Mixed effects model with repeated measures at weeks 24, 48, 72 and 96)

11 Tenofovir concentration - percentile For every 10% increase in the mean tenofovir percentile there was a 2.3 ml/min/1.73m 2 decrease in CrCl over 96 weeks (P<0.01). *Adjusted for: race, age, sex, treatment arm, time, baseline CrCl, CD4 count and HIV RNA **Black lines represent the median for each treatment group

12 17 Polymorphisms associated with change in CrCl only among TDF-treated patients ●PgP (ABCB1) and OAT-1 (SLC22A6) ■No significant associations ●MRP-2 (ABCC2) ■12 of 43 SNPs (28%) ●MRP-4 (ABCC4) ■5 of 86 SNPs (6%) Adjusted for: race, age, sex, treatment arm, time, baseline CrCl, CD4 count and HIV RNA Adjustment for multiple comparisons using False Discovery Method

13 ABCC2 rs (1249 G>A) ●In a prior study by Izzedine et al. Homozygote of minor allele at a higher frequency among patients with TDF-associated renal tubular dysfunction Izzedine et al. JID 2006

14 ABCC4 rs (3463A>G) ●In prior study by Kiser et al. Minor allele associated with 35% higher intracellular TFV-DP levels and reduced tenofovir renal clearance Kiser JJ et al. JAIDS 2008

15 Summary (1) ●Biphasic decline in CrCl among LPV/r+TDF+3TC ■Possibly slowly progressive decline beyond 6 months ●Traditional risk factors ■Age (per 10 yrs):-2.3 ml/min/1.73m 2 ■Female:-3.2 ml/min/1.73m 2 (P=0.07) ■CD4 (per 100 cell/mm 3 dec):-1.0 ml/min/1.73m 2 ■HIV RNA level (per log 10 c/ml):-2.9 ml/min/1.73m 2 ●Regimen type (vs. EFV/TDF/3TC) ■LPVr/TDF/3TC:-11.4 ml/min/1.73m 2

16 Summary (2) ●Dose-response relationship with early tenofovir exposure (weeks 4, 12 and 16) and CrCl change over 96 weeks ■Minimum plasma TFV (per 10%):-2.1 ml/min/1.73m 2 ●Possible mechanistic role of genetic variants in ABBC2 (MRP-2) and ABBC4 (MRP-4) in TDF-associated renal toxicity ■Homozygous carriers of minor alleles in drug transporters  ABCC2 (rs ):-27 ml/min/1.73m 2  ABCC4 (rs ): -28 ml/min/1.73m 2

17 Acknowledgements ●A5142 participants ●A5142 study team ■Richard Haubrich ■Sharon Riddler ●Statisticians ■Yu (Evelyn) Zheng ■Michael Hughes ●TFV pharmacokinetics ■Stan Louie ■Michael Neely ●Genetic testing ■David Haas ●Grant support UCSD Department of Medicine HIV/AIDS Clinical Trials Unit (5 U01 AI ), National Institute of Allergy and Infectious Diseases (K24 AI and K23 AI066901), University California San Diego Center for AIDS Research (5P30 AI 36214);