Disclosure. Companies/funders. Research grants (to the institute) Merck, Gilead, Janssen, ViiV. Speakers fee. Viiv, Abvie, Gilead.

Transcription

1

2 Disclosure Companies/funders Research grants (to the institute) Merck, Gilead, Janssen, ViiV Speakers fee Viiv, Abvie, Gilead Other Co-owner/Scientific director Virology Education

3

4 Integration Insertion of the viral DNA into host chromosomal DNA Essential step in cycle Point of no return: cell becomes a permanent carrier Cause of persistence and the barrier to cure ( eg HCV)

5 The HIV life cycle entry reverse transcription transcription integration virus production nuclear import Hazuda 2012

6 Integration (two phases) 3 processing: 2/3 nucleotides are removed from the 3 ends from the DNA strand at both sides of the viral DNA Strand transfer reaction: the processed 3 ends of viral DNA are covalently bound to the host chromosomal DNA

7 Craigie and Bushman 2012 The mechanics of integration

8 Integrase structure Zinc Finger Catalytic Core DNA Binding H H C C D64 D116 E152 SH Asp-Asp-Glu (DDE) motif binds Mg2+ Motif is well conserved in evolution 8

9 Integrase resistance in raltegravir studies 41 failures: 32 integrase mutations following three pathways - N155H (E92Q,V151I,T97A,G163R,L74M) - Q148K/R/H (G140S,E138K) - Y143R (L74A,E92Q,T97A,I203M,S230R)

10 RAL AND EVG: PRIMARY (RESISTANCE ) AND SECONDARY MUTATIONS (RESISTANCE AND COMPENSATORY) Drug Primary resistance mutations 1,2 RAL and EVG RAL and EVG RAL EVG Q148R/H/K N155H Y143C/H/R T66A/I/K Numerous secondary mutations* increase resistance and/or improve replication capacity 2 G140A/S E138A/K T97A L74M E92Q EVG E92Q/G EVG S147G *Additional mutations that occur after the virus has gone down one of three resistance pathways RAL, raltegravir; EVG, elvitegravir 1. Mbisa JL, et al. Infect Drug Resist 2011;4: Johnson VA, et al. Top Antivir Med 2013;21:6 14

11 Inhibitory concentration IC 50 Sensitive : Resistant : Fold Increase IC50

12 Primary mutations and cross resistance elvitegravir and raltegravir Fold change (IC50)) elvitegravir raltegravir Q148K/R 67/118 34/30 N155H N155H+E92Q Q148H+G140S >1000 >1000

13 Resistance evolution Raltegravir and Elvitegravir - Clinical failure to raltegravir and elvitegravir requires one primary/resistance mutation causing high level resistance. - Continuation of failing therapy leads to acquisition of additional resistance mutations as well as compensatory mutations restoring replicative capacity. - In most cases the resistant virus selected by one will be (cross) resistant to the other inhibitor. 13

14 In vitro resistance studies with the second generation (DTG and BIC)

15 IN VITRO MOST SINGLE RAL- AND EVG MUTATIONS - RESISTANT CONFER NO OR SMALL CHANGES IN DTG IC50 Mean FC Viruses DTG RAL EVG WT 1, T66A 1, T66I 1, T66K 1, E92I 1, E92Q 1, E92V 1, G118S 1, F121Y 1, T124A 1, E138K 1, G140S 1, Y143C 1, Y143H 1, Mean FC Viruses DTG RAL EVG Y143R 1, P145S 1, >350 Q146R 1, Q148H 1, Q148K 1, >1700 Q148R 1, I151L 1, S153F 1, S153Y 1, M154I, N155H 1, N155S 1, N155T 1, G193E FC < 5 5 FC < FC RAL and EVG-related single mutation SDMs (site directed mutants) 1. Adapted from Kobayashi M, et al. Antimicrob Agents Chemother 2011;55: Adapted from Seki T, et al. CROI Abstract 555

16 SOME DUAL COMBINATIONS WHICH INCLUDE 148 MUTANTS CAN CONFER LARGE CHANGES IN DTG IC50 Mean FC Viruses DTG RAL EVG WT T66I/L74M T66I/E92Q T66K/L74M L74M/N155H E92Q/N155H 2.5 > T97A/N155H L101I/S153F F121Y/T125K E138A/Q148R E138K/Q148H E138K/Q148K E138K/Q148R FC < 5 5 FC < FC Mean FC Viruses DTG RAL EVG G140C/Q148R G140S/Q148H 2.6 >130 >890 G140S/Q148K G140S/Q148R Y143H/N155H Q148R/N155H 10 > N155H/G163K N155H/G163R N155H/D232N V72I/F121Y/T125K L101I/T124A/S153F E138A/S147G/Q148R V72I/F121Y/T125K/I151 V RAL and EVG-related single mutation SDMs (site directed mutants) Adapted from Kobayashi M, et al. Antimicrob Agents Chemother 2011;55:813 21

17 cross resistance patterns

18 In vitro selection of dolutegravir resistance Quashie et al J virol 2012

19 DTG IN-VITRO RESISTANCE PROFILE VERSUS RAL OR EVG DURING PASSAGE STUDY DTG (56 days)1,2 FC = S153F DTG (84 days)1,2 FC = S153Y S153F DTG (112 days)1,2 FC = S153Y S153F RAL (84 days) 1,3,4 FC = 6 >138 Q148K Q148R E138K/Q148K E138K/Q148R G140S/Q148R N17S/Q148K/G163R G140C/Q148K/G163R E138K/Q148K/G163R E92Q/E138K/Q148K/M154I N155H/I204T V151I/N155H V151I/N155H EVG (56 days) 1,3 FC = T66I E92Q P145S Q148K Q148R T66K E92V P145S Q146L Q148R T66I/V72A/A128T T66I/E92Q T66I/Q146L Integrase substitutions observed during passage of wild-type HIV-1 IIIB strain in the presence of DTG, RAL or EVG; list excludes polymorphisms. Mutations in bold indicate those seen in clinical trials All substitutions observed during DTG passage conferred relativel small changes in IC50 ( 4.1 fold) 1,2 1. Adapted from Sato A, et al. IAS Poster WEPEA Data on file (Global Data Sheet).3. Kobayashi M, et al. Antiviral Research 2008;80; Kobayashi M, et al. Antimicrob Agents Chemother 2011;55:813 21

20

21

22 In vitro passage DTG and BIC The most common selected mutations are R263K, S153Y (G118R subtype C) The R263K can be selected by both BIC and DTG (EVG) and can be accompanied by one or more of the following mutations (M50I,T66I, S153Y and S119R). These additional mutations by themselves confer low fold increases in IC50 (4-10 X) to both BIC and DTG. Combinations of the mutations above do not lead to large further in creases in IC5O, suggesting that these additional substitutions are mostly compensatory.

23 Relative binding INI DISSOCIATION FROM WT IN-DNA COMPLEX AT 37 C DTG RAL EVG Time (h) INI k off (s -1 ) t 1/2 (h) DTG 2.7 x RAL 22 x EVG 71 x DTG dissociated more slowly from a WT IN-DNA complex at 37 C compared with RAL and EVG DTG dissociation was eight times longer than RAL and 26 times slower than EVG K off, dissociation rate; t 1/2h, half-life in hours Adapted from Hightower KE, et al. Antimicrob Agents Chemother 2011;5:4552 9

24 Virology findings from DTG clinical studies in INSTI RESISTANCE subjects

25 VIKING-3 Main eligibility criteria: HIV-1 RNA 500 c/ml Screening or documented historic evidence of resistance to RAL and/or EVG, and resistance to 2 ARV classes other than INIs OSS, overall susceptibility score, determined by Monogram Biosciences net assessment Castagna A. Journal of Infectious Diseases January 19, 2014

26 *INI resistance = presence of T66A/I/K, E92Q/V, Y143C/H/R, Q148H/K/R, N155H or a RAL FC >1.5 or EVG FC >2.5; 68% at screening, 32% with documented resistance from prior INI failure DRV/r, darunavir/ritonavir; ENF, enfuvirtide; ETR, etravirine; MVC, maraviroc NNRTI, non-nucleoside reverse transcriptase inhibitor; PI, protease inhibitor Prior ART and resistance at baseline Characteristic DTG 50 mg BID (N=183) Prior ART Duration in years, median 13 year Number of ARVs, median 14 drugs DRV/r 73% ETR 56% ENF 49% MVC 32% Resistance, n (%) INI (RAL and/or EVG)* 100% 2 NRTI resistance-associated mutation 75% 1 NNRTI resistance-associated mutation 70% 2 PI resistance-associated mutation 62%

27 VIKING-3 Functional DTG monotherapy phase DTG 50 mg BID and continue failing ART regimen Screening visit Day 1 Day 8 Castagna A. Journal of Infectious Diseases January 19, 2014

28 DTG VIROLOGIC RESPONSE AT DAY 8 BY BASELINE MUTATIONS Median decline IN mutation group N in HIV-1 RNA (log 10 c/ml) Full response, a No Q % Q b % Q b % a Full response: decline in HIV-1 RNA >1 log 10 c/ml or <50 c/ml at Day 8 b L74I, E138A/K/T and G140A/C/S Adapted from Vavro C, et al. IDRW Abstract 29

29 Virology findings from Phase III DTG clinical studies in INI NAÏVE subjects

30 SAILING: phase III trial in treatment-experienced, INI-NAÏVE subjects ARV-experienced, INI-naïve adults HIV-1 RNA 400 c/ml* Resistance to 2 classes of ARVs (not incl. INIs) Stratified by HIV-1 RNA ( or >50,000), DRV/r use and no. of fully active drugs in OBR *With 2 consecutive HIV-1 RNA 400 c/ml, unless screening HIV-1 RNA >1,000 c/ml Cahn P, et al. Lancet 2013;382:700-8

31 SAILING: treatment-experienced, INI-NAÏVE subjects DTG 50 mg QD plus optimised background regimen (n=354) RAL 400 mg BID plus optimised background regimen (n=361) Interim analysis Week 24 Analysis Week 48 Primary endpoint: proportion of subjects with HIV-1 RNA <50 c/ml at Week 48 *With 2 consecutive HIV-1 RNA 400 c/ml, unless screening HIV-1 RNA >1,000 c/ml Cahn P, et al. Lancet 2013;382:700-8

32 CUMULATIVE SUMMARY OF PDVFs BY VISIT (MITT-E POPULATION) THROUGH WEEK 24 DTG 50 mg QD RAL 400 mg BID Week, n (%) N=354 N=361 Week 8 1 (<1) 1 (<1) Rebound 1 (<1) 1 (<1) Week 12 4 (1) 6 (2) Rebound 4 (1) 6 (2) Week (3) 21 (6) Virologic non-response 0 13 (4) Rebound 10 (3) 8 (2) Week (4) 34 (9) Virologic non-response 1 (<1) 19 (5) Rebound 13 (4) 15 (4) PDVF: virologic non-response - if plasma HIV-1 RNA levels had decreased <1 log 10 c/ml (unless <400 c/ml) by Week 16, or were 400 c/ml on or after Week 24; virologic rebound - if plasma HIV-1 RNA levels increased to 400 c/ml following confirmed suppression to <400 c/ml, or if >1 log 10 c/ml above nadir (lowest value 400 c/ml). Suspected PDVF required confirmatory testing; suspect time point was tested once confirmed. Adapted from Underwood MR, et al. IDRW Abstract 21

33 HIV-1 RNA (log 10 c/ml) SUBJECT 1: R263K Day 1: Clade B; PSS=2, GSS=2 Regimen (PSS Day 1 ): TDF(1) and DRV/r(1) DTG C0 a : Week 4=0.57 µg/ml DTG IC50: 1,1 fold Week Day 1 PDVF IN mutation - R263R/K DTG FC RAL FC IN RC 61% 33% PDVF BR: No emergent IAS, nor increased FC a Mean Week 4 + Week 24 C0 was 0.86 µg/ml Adapted from Underwood MR, et al. IDRW Abstract 21

34 HIV-1 RNA (log 10 c/ml) SUBJECT 2: R263K/V260I Day 1: Clade C; PSS=1, GSS=0.75 Regimen (PSS Day 1 ): TDF(0) and EFV(1) DTG C0 a : Week 4=<0.02 µg/ml (BLOD); Week 24=0.26 µg/ml DTG: IC50 2 fold Day 1 PDVF IN mutation - V260I/R263K DTG FC RAL FC IN RC 119% NR PDVF BR: Emergent RT G190S; EFV FC increase : Day 1 TDF (PSS=0) + EFV active DTG trough level <0.02 µg/ml (BLOD) indicates dose 3 days prior a Mean Week 4 + Week 24 C0 was 0.86 µg/ml BLOD, below limit of detection

35 HIV-1 RNA c/ml Subject 3: R263K/S230R Day 1: Clade B; PSS = 2, GSS = 2 Regimen (PSS Day 1 ): tenofovir (1) and emtricitabine (1) DTG C0 a : Wk 4 = 0.36 µg/ml, Wk 24 = 0.22 ug/ml, Wk 48 = 0.03 ug/ml DTG IC50: 5 FOLD Day 1 PDVF Confirm. HIV-1 RNA IN - A49G, S230R, mutation R263K a Geometric Mean Week 4 + Week 24 C µg/ml (CVb=140%) b Could not be determined A49G, S230R, R263K DTG FC RAL FC IN RC* 20% 7.1% 12% PDVF BR: No emergent resistance, and no NRTI resistance at any time points Decreased replication capacity with A49G,S230R,R263K substitutions * Wildtype RC = 100%

36 HIV-1 RNA c/ml Subject 4: N155H/I60L/T97AS Non-adherent with investigational product (IP)(protocol deviation Day 1: Clade C; PSS = 2, GSS = 2 Regimen (PSS Day 1 ): tenofovir (1) and darunavir/r (1) DTG C0 a : Wk 4 = 1.78 µg/ml, Wk 24 = not evaluable, Wk 48 = 1.23 µg/ml DTG IC50: 2,4 fold Week Day 1 PDVF HIV-1 RNA IN mutation - I60L, T97A, N155H DTG FC RAL FC IN RC NR b NR PDVF BR: No emergent resistance, loss of RT M184V and PI L10F, M36I, M46I, I54V, V82A. a Geometric Mean Week 4 + Week 24 C µg/ml (CVb=140%) b Could not be determined * Wildtype RC = 100%

37 HIV-1 RNA c/ml DTG trough below limit of detection Week 24 Subject 5: N155H Day 1: Clade A; PSS = 2, GSS = 0.5 Regimen (PSS Day 1 ): abacavir (1) and lamivudine (1) DTG C0 a : Wk 4 = 1.14 µg/ml; Wk 24 = <0.02 µg/ml (BQL); Wk 48 = 1.60 µg/ml DTG IC50: 1,8 FOLD Day 1 PDVF HIV-1 RNA IN mutation - N155H DTG FC RAL FC Week IN RC NR b NR PDVF BR: No emergent resistance, loss of M184M/V a Geometric Mean Week 4 + Week 24 C µg/ml (CVb=140%) b Could not be determined

38 Rational for DTG monotherapy studies High genetic barrier to resistance observed in patients Clinical studies using DTG containing cart and dual therapy (3TC/rilpivirine) Clinical practice Only one case report of INSTI naive patient failing on cart containing DTG Genetic barrier to resistance observed in vitro Classical single INSTI-RAMs confer low level changes in IC50 We performed a randomised clinical study to evaluate the efficacy of DTG monotherapy as maintenance in patients with well controlled HIV infection during previous cart comparing efficacy of DTG monotherapy to continuation of cart.

39 DOMONO study (NTC ) randomized clinical trial on DTG maintenance monotherapy Inclusion criteria: CD4 nadir > 200 cells/mm3, and HIV1-RNA zenith < copy/ml Self reported therapy adherence > 95% HIV1-RNA < 50 copy/ml, > 6 months Exclusion criteria: Documented virological failure on any cart Documented RAMs Virological failure (VF): Defined as 2 consecutive plasma HIV1-RNA > 200 copy/ml Wijting et al., CROI, Wijting et al. submitted

40 EFFICACY DOMONO At week 48: DTG maintenance monotherapy: viral suppression 92% (87/95), 8 patients with VF, all subtype B) Concurrent control group: viral suppression (98%) 149/152 DTG monotherapy inferior Premature stop of study Wijting et al., CROI, Wijting et al. submitted

41 Two failing patients from the pilot study Data from pilot study of NTC Same inclusion criteria as main study except here CD4 nadir < 200 cells/mm3. 4 patients included. 2 patients VF. 2/2 patients HIV subtype B and INSTI naive Premature stop of pilot study

42 Baseline characteristics of all ten patients with VF Age (median) 47 years HIV1-RNA zenith (median, copy/ml) CD4 nadir (median, cell/mm3) 230 HIV-1 subtype B (9/10), CRF02_AG (1/10) INST-naive (pat 5 raltegravir suppressed) 9/10 Time between diagnosis and start cart (median) Time on cart (median) Time suppressed on cart (plasma HIV1 RNA < 50 cop/ml (median) 47 months 72 months 59 months

43 Mechanism causing failure Drug levels Self-reported therapy adherence Plasma concentrations DTG (single measurement during VF) Resistance Sanger sequencing integrase gene (INSTI, and other substitutions) Changes outside integrase (Mallet et al, Cynthia Lungu et al)

44 Plasma DTG levels adequate and >95% Therapy Adherence Patient Plasma DTG level mg/l during VF adequate > 0.5 mg/ (hrs after last dose) Self-reported adherence (+14h) >95% (+19h) >95% (+16h) >95% (+22h) >95% (+24h) >95% (+24h) >95% (+13h) >95% (+9h) >95% (+19h) >95% (+16h) >95%

45 Weeks to virological failure and plasma HIV1-RNA levels Patient Time to VF (wks) Plasma HIV1-RNA (c/ml) at VF

46 INSTI-RAMs and additional integrase substitutions patient INSTI-RAM Additional integrase substitutions 1 none VI32I, LS45L, T112A 2 < LOD < LOD 3 none A10D, D11E, N17S, L45Q, I50M, T111K, A112T, T124S, I135V, KR211K, I220L 4 S230R EV13E, LV45L 5 < LOD < LOD 6 none G24GNDS, R111RK, A124AT, A229D, S283G 7 E263K ED10E, ED11E, L45I, F121FV, RK231K, LF234L 8 N155H D41G, T111A, S119R, M208I 9 None IV72V, LI101I 10 E92Q+N155H T112I

47 Viral dynamics during DTG maintenance failure

48 Dolutegravir-Lamivudine as Dual Therapy in Naive HIV-Infected Patients: A Pilot Study (PADDLE) Small 20 patient pilot study (ongoing in Argentina) HIV+ drug naïve: CD4 >200, HIV RNA <100,000 Start and continue dual therapy: DTG 50 mg + 3TC 300 mg Outcome: Percent HIV RNA <50 at Week 48 ARV- naïve patients 18 years HIV-1 RNA >5,000 copies/ml and <100,000 copies/ml CD4 count 200 cells/ml HB(s)Ag negative (n= 20) P. Cahn. CROI, Boston March 2016

49 PADDLE: Median VL decay baseline - to 28 days Viral Load (Log 10) Median VL decay baseline-to day 28= 2.72 logs (IQR:-2.98/-2.92) Days P. Cahn. CROI, Boston March 2016

50 Viral suppression at week 48 P. Cahn. IAS, Durban July 2016

51 Patient 19: Viral load evolution (copies/ml) at virological failure by visit. Patient discontinued from study but followed off study until week 48 without change of his DTG + 3TC Cahn P et al. Journal of the International AIDS Society 2017, 20:21678

52 Conclusions First generation (RAL&EVG) have overlapping resistance profiles and low genetic barrier DTG retains activity against preferred mutations selected by the first generation, but combinations of mutations can severly affect it activity. Preferred resistance pathways for the second generation differs from the first eg other mutations and the fenotypic resistance effect of these mutations is much smaller, however if they develop they can confer cross resistance. Resistance development using fully active triple regimens containing DTG or BIC is extremely rare. Under particular circumstances eg monotherapy or low drug levels combined with suboptimal background therapy resistance causing low viral load failures can occur

53 Conclusions DTG resistance does not occur in compliant patients taking dual (3TD and rilpivirine) therapies. Final results of large clinical trials are underway.