HIV co-receptor tropism in treatment-naïve patients: impact on CD4 decline and subsequent response to HAART Laura Waters, Sundhiya Mandalia, Adrian Wildfire, Paul Randell, Brian Gazzard & Graeme Moyle. St Stephen’s Centre, Chelsea & Westminster Hospital, London, UK

R5 viruses (M-tropic, NSI) Transmitted variants Prevalent in early disease X4 viruses (T-tropic, SI) Late disease; associated with CD4 decline, HIV RNA increase and clinical progression Dual-tropic viruses use CCR5 or CXCR4 (in vitro) CCR5 Q L S D T F F L R A P I A L H Y V L V W L F I L S T V L A L I V I V V Y A S L Y N H S Y V P I F L A G V I D T F L V V W P L I A I C I I V G H Y I L G L I I C I S L P M V I L T F Y G W I I V F I P S C L T A Y L I A G V I T Y P I I G L G L T S F F N V I V I I L L M G Y L N F C A I F W P Y C L T L I F I A L G G A S H A K D L K K M T RS D F L C K N Y F G D R Y L A I V NS R P R K L L A K E H T Q V S E A D D R Y I C D N DL W V V V F Q F Q F P Y R S K L S K L A K R K Q HG K S H D S F I L L E I I KQ G C E F E N T H K V L K K L F K T S A Q H V S R G S S A T S G I L S K G K R T E S E SS S F G H S S V S H S S V A A N W K N F N A N E E R F C P E K M S D Y D G S G M E E T Y N D S T Y I S I GE M - NH 2 * * * N F A CXCR4 352 C L A D T F F H L L S P L A F N Y I V L W L L F I G F G F L I L I L I L F I T F Y G T S S T V L I F T I T V G S F V V V W P A I A G C M V L L I Y I V G L V L S L I L P I V T I L F Y V W L M F Y I P L F I I V N A L L M V I F Y P V G L G L S L F N V F I L L I L I N I N F C T V M A P Y C V T L M T I A I G E G Q H E I D L K R M T K S Y T M C Q N F G R Y L A V V A FA K A R T V T F V G H VL S Q K EG L H Y T C S Y S QY Q F W K N F Q H P F S K T L L V H R K KE N R C R N T F Q E F F G L N N C S S S N R D Q L C K K F F RN Y L L V H I AK R F F Q K A C C S I F QQ S V Y TR S T G E P E R A S E Q E A A A Q A A I Q K V N I K Q C P E S T YY N I D Y I P S S V Q YDM - NH 2 - COOH R T L R A I S VG L R P L D K R 277- D W CCR5- & CXCR4-tropic HIV

Prevalence of Co-receptor Usage Study/SourcePopulationR5X4X4/R5 Maraviroc Phase 2 a Naive9406 Homer cohort b (n=979) Naive83<117 C & W cohort c (n=563) Naïve/ Experienced 85<115 GSK d (n=299) Naive88012 TORO 1/2 e Experienced62434 ViroLogic f Experienced50248 a Data on filed Demarest et al. ICAAC Abstract H-1136 b Brumme ZL et al. JID 2005;192(3): e Whitcomb et al. CROI Abstract 557 c Moyle GJ et al. JID 2005;191(6): f Huang et al. ICAAC Abstract 2040

Prevalence and Predictive Factors for R5 and X4 Coreceptor Usage Prevalence (%) CD4 (cells/mm 3 ) 84.3% 59.3% (n=81) (n=185) (n=248) (n=81) (n=185) (n=248) 83.5% R5 Prevalence 563 HIV patients –85% male –66% Caucasian –Mean age: 44 years –Clade B: 76% –R5 tropic: 85% –R5/X4 dual tropic: 15% Moyle GJ, et al. JID 2005 Mean R5 Tropic R5/ X4 Tropic CD4 (cells/mm 3 ) 307*231 HIV RNA (copies/mL) 35,800 † 66,228 *P=0.007; † P<0.001.

Prevalence of R5 Use by Baseline CD4 and HIV RNA Levels Prevalence of R5 Use (%) Baseline CD4 (cells/mm 3 ) >100K >100K Baseline HIV RNA (copies/mL) >5-50K >5-50K >50-100K >50-100K <5K <5K n=563. Moyle GJ, et al. JID 2005

Clinical Progression & Response to HAART Swiss HIV Cohort 96 progressors vs. 84 matched non-progressors R5 at baseline (n=84) X4/R5 at baseline (n=84) Significance CD4 rise at 6 months 8240p = HIV RNA < 500 at 6 months 57 (68%)27 (32%)p = 0.33 Hazard ratio for clinical progression % CI 1.83 – 8.72 Phillpott et al. IAS Abstract THAA0201

Determination of R5/X4 Tropism Two potential roles for tropism testing: Guiding therapy decisions Predicting disease progression

Aim To study the impact of R5/X4 tropism as determined by the ViroLogic Phenosense Assay on: The rate of CD4 decline prior to commencing therapy Response to therapy: - CD4 rise - Time to HIV RNA < 50 c/mL - Proportion with HIV RNA < 50 c/mL

Methods Study Design Subjects from epidemiology study: R5 tropic vs. X4/mixed/dual tropic Prospective cohort database used to record: - Sequential CD4 counts from tropism test to HAART initiation (censored if < 3 months) - Sequential CD4 counts and HIV RNA after HAART - HAART regimen prescribed

Methods Response to HAART HAART defined as: - ≥ 2NRTI + NNRTI - ≥ 2NRTI + PI (unboosted) - ≥ 2NRTI + PI/r (boosted) Exclusions: - Non-HAART regimens - < 6 months follow-up Data censored at: - 96 weeks - End of follow-up - Therapy switch for virological failure

Methods Statistics CD4 decline: DAVG using MIXED model adjusted for baseline HIV RNA CD4 response to HAART: univariate + multivariate linear MIXED model (adj. for baseline HIV RNA and HAART) Proportion with HIV RNA < 50 c/mL:  2 test Time to HIV RNA < 50 c/mL: survival analysis; Cox’s proportional hazards regression to adj. for baseline HIV RNA and HAART

Results 402 naïve subjects tropism tested: R X4/R5 (mixed/dual) - 3 X4 340 commenced HAART by August excluded from analysis* R X4/mixed/dual 62 remained off therapy *< 6/12 follow-up (n=28); non-HAART (n=23)

Baseline Demographics R5-tropic (n=326) X4/R5 (n=76) p-value Male288 (88.3%)72 (94.7%)0.101 White Black Other 236 (72.4%) 44 (13.5%) 46 (14.1%) 50 (65.8%) 9 (11.8%) 17 (22.4%) CD4 (IQR)325 ( )203 (58-375)<0.001 HIV RNA (IQR)39385 ( ) ( )<0.001 Mutations NRTI NNRTI PI Clade B Clade Other Untested 252 (77.3%) 57 (17.5%) 17 (5.2%) 64 (84.2%) 11 (14.5%) 1 (1.3%) 0.242

Baseline Genotypic Resistance R5-tropic (n=326)X4-tropic (n=76)p-value NRTI mutations: ≥4 untested 286 (87.7%) 19 (5.8%) 4 (1.2%) 2 (0.6%) 1 (0.4%) 14 (4.3%) 66 (86.8%) 5 (6.6%) 1 (1.3%) 2 (2.7%) PI mutations: ≥4 untested 304 (93.3%) 3 (0.8%) 2 (0.6%) 1 (0.4%) 2 (0.6%) 14 (4.3%) 69 (90.8%) 2 (2.7%) 1 (1.3%) 2 (2.7%) NNRTI mutations 0 1 ≥2 untested 302 (92.6%) 6 (1.8%) 4 (1.2%) 14 (4.3%) 71 (93.4%) 1 (1.3%) 2 (2.7%) 0.893

Duration since sample result (months) CD4 count from time when sample taken Naïve : R5Naïve : X4/R5 DAVG analysis (time weighted differences in average. Censored at HAART; Error bars are 95% CI p = p = R5 n= X4 n= CD4 decline before HAART

R5 n= X4 n= CD4 rise on HAART Duration since sample result (months) CD4 count from time when sample taken Naïve: R5Naïve: X4/R5 Time weighted differences in averages (DAVG) from baseline estimated using linear MIXED model

CD4 rise on HAART R5X4/R5p-value 12 months mean (95% CI) 185 ( ) 182 ( ) months mean (95% CI) 247 ( ) 292 ( ) 0.482

Rates of Viral Suppression 289 subjects (229 R5, 60 X4/R5) started HAART R5 tropic (n=229) X4/R5 tropic (n=60) p-value N (%) with HIV RNA < 50 at 6 months 163 (71.2%) 45 (75.0%) N (%) with HIV RNA < 50 at 12 months 168 (73.4%) 47 (78.3%) N (%) with HIV RNA < 50 at 24 months 166 (72.5%) 41 (68.3%) 0.670

Time to Viral Suppression Duration since sample result (months) Proportion achieving VL<50 copies/ml R5X4/R5 R5 n= X4 n= Survival analysis; Cox’s proportional hazards regression to adjust for baseline HIV RNA and HAART

Conclusions Subjects with X4 HIV-1 experience more rapid CD4 decline than those with R5 patients (adjusted for baseline viral load) Similar proportions achieve viral suppression at 1 year and 2 years CD4 rise similar over 96 weeks of HAART Time to viral suppression same for R5 and X4 virus when adjusted for baseline viral load

Acknowledgements Dr Marta Boffito All the St Stephen’s Centre patients Pfizer for funding of tropism testing Monogram Biosciences