Resistance Characteristics of Integrase Inhibitors

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1 Resistance Characteristics of Integrase Inhibitors Madrid, November 2016 Jonathan M Schapiro, MD National Hemophilia Center, Israel Stanford University School of Medicine, USA

2 Disclaimer Presentation includes investigational drugs not approved for use outside of clinical trials

3 Integrase Inhibitors Raltegravir (RAL) Elvitegravir (EVG) Dolutegravir (DTG) Cabotegravir - Investigational data accumulating Bictegravir (BIC) Investigational preliminary data only

4 Integrase Inhibitors Raltegravir (RAL) Elvitegravir (EVG) Dolutegravir (DTG) Cabotegravir - Investigational data accumulating Bictegravir (BIC) Investigational preliminary data only Resistance characteristics are substantially different Between first and second generation integrase inhibitors

5 Integrase Inhibitors Bictegravir

6 Dolutegravir

7 Bictegravir

8 Cabotegravir

9 Integrase Inhibitors Second Generation Cabotegravir Bictegravir

10 Integrase Inhibitor in Active Site RCSB Protein Data Base

11 Integrase Inhibitor in Active Site RCSB Protein Data Base

12 Key Raltegravir Mutations Stanford HIV Data Base

13 DTG versus RAL Alignment in Active Site DTG RAL

14 Dolutegravir Dolutegravir was developed specifically to have improved resistance characteristics The structure was continually changed to improve resistance characteristics (reducing fold change of resistance mutations)

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16 Mean FC of Site Directed Mutants identified During Passage with Wild-type Virus in the Presence of S/GSK Viruses Mean FC S/GSK S153F 1.6 S153Y 2.5 L101I/S153F 2.0 L101I/T124A/S153F 1.9 Adapted from Seki et al, CROI 2010

17 EC 50 Fold Change RESISTANCE OF INTEGRASE MUTATIONS TO DIFFERENT INTEGRASE INHIBITORS Q148K G140S/Q148H G140C/Q148R E138K/Q148R Q148R/N155H E138K/Q148K P145S E92Q/N155H G140S/Q148R E138A/Q148R Q148R T66I/E92Q E138A/S147G/Q148R T66K/L74M G140S/Q148K T66K N155S V72I/F121Y/T125K F121Y/T125K L74M/N155H N155T V72I/F121Y/T125K/I151V T79A/N155H N155H/D232N F121Y N155H/G163K N155H/G163R I151L N155H E92Q Y143H/N155H T66I/L74M E92V E92I T66I Q148H E138K/Q148H T66A Q146R G140S S153Y G118S S153F L101I/S153F L101I/T124A/S153F Y143R Y143C Y143H T124A M154I E138K L101I* Integrase mutants EVG RAL DTG *Not tested for EVG EC 50, 50% effective concentration 1. Adapted from Seki T, et al. CROI Poster J Adapted from Kobayashi M, et al. Antimicrob Agents Chemother 2011;55:813 21

18 Genetic Barrier to Resistance: Virology and Pharmacology

19 Plasma concentration of Drug Genetic Barrier to Resistance: Virology and Pharmacology Drug level Time (hours)

20 Plasma concentration of Drug Genetic Barrier to Resistance: Virology and Pharmacology Drug level Drug level to inhibit WT virus Time (hours)

21 Plasma concentration of Drug Genetic Barrier to Resistance: Virology and Pharmacology Drug level Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus Time (hours)

22 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus

23 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus

24 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) Is this the clinically relevant Genetic Barrier to Resistance? Drug level to inhibit WT virus

25 Correcting for Protein Binding of Drug in Plasma Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus

26 Correcting for Protein Binding of Drug in Plasma Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

27 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) What is Missing? Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

28 How Much Resistance from a Single Mutation to the Drug Minimal Plasma level of drug (Cmin) Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

29 How Much Resistance from a Single Mutation to the Drug Minimal Plasma level of drug (Cmin) Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

30 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

31 Estimating the Barrier to Resistance Minimal Plasma level of drug (Cmin) Drug with potentially high genetic barrier to resistance Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

32 Estimating the Barrier to Resistance Drug level to inhibit most potent single mutation to the drug Minimal Plasma level of drug (Cmin) Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

33 Estimating the Barrier to Resistance Drug level to inhibit most potent single mutation to the drug Minimal Plasma level of drug (Cmin) Drug with potentially Low genetic barrier to resistance Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

34 Factors Contributing to a High Genetic Barrier to Resistance Minimal Plasma level of drug (Cmin) Potentially High Genetic Barrier Fold Change Resistance of Single Mutant = 3 Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

35 Factors Contributing to a High Genetic Barrier to Resistance Fold Change Resistance of Single Mutant = 30 Drug level to inhibit most potent single mutation to the drug Minimal Plasma level of drug (Cmin) Potentially Low Genetic Barrier Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

36 Structure of Protease Inhibitor Darunavir

37 Structure of Protease Inhibitor Amprenavir

38 Structure of Protease Inhibitor Amprenavir

39 Structure of Protease Inhibitor Darunavir

40 Darunavir versus Amprenavir Resistance: Fold Change to Identical Mutations

41 Genetic Barrier to Resistance DRV/r 600/100 BID Minimal Plasma level of drug (Cmin) DRV/r Genetic Barrier to Resistance Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

42 Genetic Barrier to Resistance LPV/r 400/100 BID Minimal Plasma level of drug (Cmin) LPV/r Genetic Barrier to Resistance Drug level to inhibit most potent single mutation to the drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

43 Estimated Genetic Barrier of Efavirenz Drug level to inhibit most potent single mutation to the drug Minimal Plasma level of drug (Cmin) Low Genetic Barrier Drug Drug level to inhibit WT virus corrected for protein binding Drug level to inhibit WT virus

44 Resistance Characteristic of Integrase Inhibitors Clinical Significance

45 Resistance Accumulation in Patients Failing First Generation Integrase Inhibitors

46 Do Resistance Mutations Accumulate Over Time if Patients Have Low Level Viremia?

47 PLoS ONE May 2012

48 Impact of Low-Level-Viremia on HIV-1 Drug-Resistance Evolution among Antiretroviral Treated-Patients 48 highly-treatment experienced patients, on salvage regimens 2 NRTI + PI/r +/- NNRTI and or RAL LLV defined as HIV RNA copies on at least 3 occasions over 6 months or more (Mean follow up 11 months) Resistance testing done on first and last HIV RNA test Accumulation of additional mutations during LLV determined

49 Accumulation of Mutations at HIV RNA Below 500 copies

50 Accumulation of Mutations at HIV RNA Below 500 copies 10% developed new major DRV MU

51 Accumulation of Mutations at HIV RNA Below 500 copies 2 of 9 developed major RAL MU

52 Resistance to Second Generation Integrase Inhibitors Despite their high genetic barrier, second generation integrase inhibitors are not immune to resistance When given with 2 NRTI s in drug naïve patients, current data suggest using DTG will avoid failure with integrase resistance But one must be cautious in extrapolating to all other clinical scenarios Mono or dual therapy Treatment experienced patients Other investigational second generation inhibitors

53 Resistance to Second Generation Integrase Inhibitors in Investigational Settings

54 Integrase Inhibitors Dolutegravir Cabotegravir

55 Resistance to Single Integrase Mutations Dolutegravir Cabotegravir

56 Fold Change in IC50 Compared With WT for CAB, DTG, RAL and EVG Against Site-Directed Mutant HIV-1 Dudas K et al. IWADR Feb 2015, Seattle

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59 Virologic Success: HIV-1 RNA <50 c/ml (ITT-E) Margolis DA et al, CROI Feb 2015, Seattle

60 Profile of a Single Subject With Treatment-Emergent Resistance on 10 mg CAB Dudas K et al. IWADR Feb 2015, Seattle

61 Resistance to Investigational Second Generation Integrase Inhibitors Clinical Validation Data generated from multiple large clinical trials and widespread routine use are available only for 2 NRTI + DTG on lack of failure with resistance Both Cabotegravir and Bictegravir currently lack such data. Initial results are promising but require further validation Only after these drugs have been used in widespread clinical settings will we know if they posses similar resistance characteristics

62 Dolutegravir (DTG) monotherapy treatment de-escalation in virological controlled, pre-treated HIV patients: Results from the DoluMono cohort study Celia Oldenbüttel et al HIV Drug Therapy, October 2016, Glasgow UK

63 DoluMono cohort study Retrospective cohort study from single center Patients on suppressive ART, undetectable at least 6 months, who were switched to DTG monotherapy as part of routine clinical practice Could have no prior integrase inhibitor failure or resistance 31 patients with 24 week follow up identified 94% remained <50 copies on DTG monotherapy One virological failure with integrase resistance HIV RNA: 538, Integrase mutations: G140 S+ Q148H

64 Integrase Inhibitors: Surveillance for Transmitted Resistance Surveillance for increasing levels of transmitted integrase resistance is key in determining if and when integrase genotyping will be required for newly infected patients Taiwan reported an INI resistance prevalence of 1.2% for integrase inhibitor naïve patients a number of years after RAL was introduced to the country This may be due to practices of RAL use and is being addressed Prevalence of integrase mutations in naïve patients may depend on a number of factors

65 Factors Impacting the Prevalence of INI Mutations Drugs used (RAL, EVG vs. DTG) Regimen used (triple, dual or monotherapy) Frequency of HIV RNA viral load monitoring Thresholds for acting on detectable HIV RNA results Availability of integrase resistance testing

66 Summary First and second generation integrase inhibitors have diverse resistance characteristics Despite all being very potent drugs, this has implications for their optimal clinical use Transmitted integrase resistance may likely have a greater impact on first, than on second generation agents Continuous surveillance for integrase transmitted drug resistance is of high importance, certainly where first generation drugs are commonly used

67 Summary First and second generation integrase inhibitors have diverse resistance characteristics Despite all being very potent drugs, this has implications for their optimal clinical use Transmitted integrase resistance may likely have a greater impact on first, than on second generation agents Continuous surveillance for integrase transmitted drug resistance is of high importance, certainly where first generation drugs are commonly used

68 Summary II Patients receiving first generation integrase inhibitors need to be monitored for failure, as mutations can quickly accumulate reducing or negating the use of second generation drugs Tolerating low level viremia in patients on first generation drugs (first line or salvage) may lead to loss of subsequent second generation option To date, convincing evidence for the lack of resistance upon failure of a second generation integrase inhibitors is available only for DTG in the context of a 2 NRTI regimen All other regimens, drugs and scenarios requires further study with sufficient numbers and follow-up

69 Thank You