1. Alex Monto, MD Professor of Clinical Medicine University of California San Francisco San Francisco, California Hepatitis C Virus Management: Dealing with Treatment Failure (Been There, Done That) FLOWED: 04/28/2016 San Francisco, California: May 6, 2016 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA.

2. Slide 2 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Learning Objectives After attending this session, participants will be able to: Identify who needs hepatitis C virus (HCV) retreatment and in what time frame Assess the different types of HCV treatment failure Recognize when to order HCV resistance testing and how to use it in therapeutic decision-making Compare the benefits of current and future HCV combination regimens for specific patients

3. Slide 3 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Glossary SOF/LDV: sofosbuvir/ledipasvir PrOD: paritaprevir with ritonavir boosting/ombitasvir/dasabuvir GZR/EBR: grazoprevir/elbasvir DCV: daclatasvir SOF/VEL: sofosbuvir/velpatasvir (expected FDA approval late 6/2016) RBV: ribavirin DAA: direct-acting antiviral (current HCV therapies that target specific HCV proteins) RAV: resistance-associated variant (RAP, polymorphism is a very similar term): change in a specific HCV gene that can be associated with lower viral susceptibility to drugs that target that gene

4. Slide 4 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Current General HCV Therapy Points “Cure” is now very genotype and sub-type specific: GT 2 > GT 1b > GT 1a > GT 3 SVR12 (sustained virological response = negative HCV RNA 12 weeks after treatment): standard outcome (SVR 24 was the old standard) SVRs in non-cirrhotics generally > cirrhotics

5. Slide 5 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. 2013201420152016 Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 2013201420152016 Combination Therapy FDA Approval Timeline Sofosbuvir + RBV ------ GT2/3, CPT A-C Daclatasvir ----- GT 3a, GT 2 SOF/LDV +/- RBV ----- GT 1, 2, 3, 4, CPT A-C PrOD +/- RBV ---- GT1b >1a, CPT A Grazoprevir/Elbasvir +/- RBV ---- GT 1b >1a, CPT A SOF/Simeprevir +/- RBV ---- GT1, CPT A SOF/Velpatasvir +/- RBV ----- GT 1, 2, 3, 4, CPT A- ?C

6. Slide 6 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Overview of DAA Activity Majumdar A et al, Aliment Pharmacol Ther 2016; Apr 18

7. Slide 7 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Forecast Burden of HCV-Related Morbidity and Mortality DCC = decompensated cirrhosis; HCC = hepatocellular carcinoma. Rein DB, et al. Dig Liver Dis. 2011;43(1):66-72. Assuming 2,700,000 HCV infected persons are in primary care  1.47 million will develop cirrhosis  350,000 will develop liver cancer  897,000 will die from HCV-related complications

8. Slide 8 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Projected HCV Sequelae Cost U.S. 1950–2030 $10 $8 $6 $4 $2 $0 1960 1950 1980 2020 2030 2000 201019901970 $3.0 $4.0 $5.0 $1.0 $0.0 $2.0 Total Cost (billions) Sequelae Cost (billions) Total Cost Decomp Cirrhosis HCC F0-F3 Liver Transplant Comp Cirrhosis Razavi H, et al. Hepatology. 2013;57(6):2164-2170. The Total Cost of Chronic HCV Is Expected to Peak in 2024 at $9.1 Billion

9. Slide 9 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. How to Think about HCV Retreatment in 2016 A few general approaches are supported both by logic and at least some empirical evidence: 1) switching to a different DAA class or classes, 2) treating for longer, and 3) adding ribavirin In most patients, HCV retreatment is not urgent HCV therapy in the setting of hepatocellular carcinoma (HCC) is controversial, and depends in part on control of HCC HCV therapy in patients being referred for or awaiting a liver transplant is controversial, and should be discussed with their transplant center

10. Slide 10 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Treating with a Different DAA Class Simple approach of switching DAA classes: obvious option for retreatment Effective, as there is no cross-resistance across DAA classes. Established by the outstanding results of clinical trials in which patients who experienced protease inhibitor (telaprevir or boceprevir) failure were retreated with combinations of a nucleotide polymerase inhibitor (sofosbuvir) and an NS5A inhibitor (daclatasvir or ledipasvir)

11. Slide 11 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. NS5A Resistance The biggest challenge in treating with a different DAA class (and by far the most important resistance issue in retreatment) NS5A resistance associated variants (RAVs) are very fit Often present even before treatment, almost always persist in patients for whom an NS5A-containing regimen fails

12. Slide 12 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Re-treat Strategy: Extend Treatment Duration Retreating patients with a longer duration of the same treatment that failed can help many patients, but it may not be enough to overcome RAVs Initial retreatment trial presented at EASL 2015 by Lawitz and colleagues. Patients for whom 8 or 12 weeks of SOF/LDV failed were retreated with SOF/LDV again—this time for 24 weeks. Among patients without NS5A RAVs, this approach worked very well: SVR12 rate of 100%. With NS5A RAVs: SVR12 only 60% Lawitz E et al, J Hepatol 2015; 62 (Suppl 2): S192

13. Slide 13 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Phase III Studies of SOF/LDV ± RBV in GT1 HCV ION-1: GT1 treatment-naive pts (16% cirrhotic): SOF/LDV ± RBV for 12 wks. ION-3: GT1 treatment-naive pts: SOF/LDV FDC ± RBV for 8 or 12 wks SOF/LDV SOF/LDV + RBV ION-2: GT1 treatment-experienced pts (20% cirrhotic): SOF/LDV FDC ± RBV for 12 or 24 wks 8 Wks12 Wks 202/ 215 206/ 216 201/ 216 12 Wks24 Wks 102/ 109 107/ 111 108/ 109 110/ 111 n/N = 209/ 214 211/ 217 SVR12 (%) 12 Wks 98 97 100 90 60 40 20 0 94 93 95 94 96 99

14. Slide 14 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. ION-2: Ledipasvir/Sofosbuvir for Tx-Exp GT 1 Characteristic 12-Wk Regimen 24-Wk Regimen LDV–SOF LDV–SOF + RBV LDV-SOF LDV-SOF + RBV (N = 109) (N = 111) (N = 109) (N = 111) Age: yr, mean 56 57 56 55 Post-treatment At 4 wk 103 (94) 107 (96) 109 (100) 110 (99) At 12 wk 102 (94) 107 (96) 108 (99) 110 (99) Virologic breakthr: 0 0 0 1 Relapse 7 (6%) 4 (4%) 0 0 * One of the 109 patients who received 12 weeks of ledipasvir–sofosbuvir had an HCV RNA level of 42 IU per milliliter N Afdhal et al, NEJM 2014;370:16 20% of pts had cirrhosis 79% GT 1a, 21% GT 1b 55% of pts had previously failed PEG-RBV-protease inhibitor No combo DAA failures

15. Slide 15 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Impact of Baseline NS5A Variants on Efficacy in GT 1 Patients C-EDGE TN: GZR/EBR for 12 Weeks in TN GT 1, 4, or 6 GT 1aGT 1b 144/157133/13511/192/9129/131112/11217/1816/17 Zeuzem, et al. Ann Intern Med 2015;163:1

16. Slide 16 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Efficacy by Prior Relapse vs. Prior Partial or Null Response Per-Protocol Analysis Kwo P, et al. J Hepatol 2015;62 (Suppl 1): S674 Relapse: primarily in prior partial or null responders treated for 12 weeks 35/3537/3735/3839/3961/6758/6462/6662/62 C-EDGE TE: GZR/EBR±RBV for 12 and 16 Weeks in TE GT 1, 4, or 6 Open-label trial: patients failing prior PEG/RBV randomized 1:1:1:1. Demographics: median age 57 years (range: 19 to 77); 64% male; 67% White; 18% Black or African American; 9% Hispanic or Latino; mean BMI 28 kg/m2; 78% HCV RNA levels > 800,000 IU/mL; 34% had cirrhosis; 79% had non-C/C IL28B alleles (CT or TT); 60% GT 1a, 39% GT 1b, 1%: genotype 1-other.

17. Slide 17 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Impact of Baseline NS5A Variants on Efficacy in GT 1 Patients Fold shift is based on assays with GT 1a replicons Kwo P, et al. J Hepatol 2015;62 (Suppl 1): S674 GT 1aGT 1b 211/223190/19211/21143/145127/12716/18 C-EDGE TE: GZR/EBR±RBV for 12 and 16 Weeks in TE GT 1, 4, or 6 10/10

18. Slide 18 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. PrOD +/-RBV SVR12, Ph 3, Treatment-Experienced, Non-Cirrhotic JM Pawlotsky, Gastro 2014;146:1176

19. Slide 19 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. TURQUOISE-II: PrOD +RBV, Ph 3, Tx-Naïve/Exp, Cirrhotic PrOD+ RBV (n=208) PrOD+ RBV (n=172) PrOD+ RBV (n=172) Wk 12 Wk 24 SVR 12-24 RBV 1000mg-1200mg Wt =75kg F Poordad et al, NEJM 2014;370:1973

20. Slide 20 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. TURQUOISE-II: PrOD +RBV SVR12, Ph 3, Tx Naïve and Exp, Compensated Cirrhosis F Poordad et al, NEJM 2014;370:1973

21. Slide 21 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. TURQUOISE-II: PrOD +RBV SVR12, Ph 3, Tx Naïve and Exp, Compensated Cirrhosis F Poordad et al, NEJM 2014;370:1973 GT 1a, prior null: 80% 12 wks, 93% 24 wks

22. Slide 22 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Audience Response Question 1 55 year old M with multiple psychiatric co-morbidities, hemochromatosis (C282Y homozygote), HCV (genotype 1a) non-cirrhotic s/p 12 week therapy w/ PrOD and Ribavirin 800 mg (started on 5/15/15) who presents with NS5A inhibitor: Resistance Mutations: Resistance Predicted: ledipasvir M28T Yes ombitasvir M28T Yes NS5B polymerase inhib: Resistance Mutations: Resistance Predicted: sofosbuvir none detected No dasabuvir G554G/S Yes HCV protease inhib: Resistance Mutations: Resistance Predicted: boceprevir none detected No simeprevir Q80K Yes paritaprevir Q80K Yes What do you want to do now? 1) treat with Sof/Led+ RBV for 24 weeks, 2) treat with PrOD and ribavirin for 24 weeks, 3) observe for several years, 4) treat with SOF/VEL +/- RBV when available

23. Slide 23 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. What do you want to do now? 1. Treat with Sof/Led+ RBV for 24 weeks 2. Treat with PrOD and ribavirin for 24 weeks 3. Observe for several years 4. Treat with SOF/VEL +/- RBV when available

24. Slide 24 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Retreatment of Combo DAA Failures N = 310 patients for whom previous IFN-free DAA therapy failed Majority of patients infected with HCV genotype 1 (63%) or 3 (22%), and received treatment for 12 (70%) or 24 (25%) weeks Previous DAA Regimen Characteristic SMV+SOF ± RBV (n = 55) LDV/SOF ± RBV (n = 114) DCV + SOF ± RBV (n = 51) PrOD ± RBV (n = 30) SOF + RBV (n = 60) Cirrhosis, % (n/N)71 (37/52)57 (62/109)70 (33/47)37 (11/30)44 (21/48) Previous regimen with RBV, %55341663100 Prior IFN therapy, % (n/N)76 (39/51)67 (67/100)76 (32/42)70 (21/30)63 (27/43) HCV genotype, % 1897957900 2000045 321339055 4984100 Tx duration with previous DAA regimen, n 8 wks013000 12 wks5380252930 16 wks01000 24 wks12026129 Vermehren J, et al. EASL, Barcelona, April 13-17, 2016; PS103

25. Slide 25 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Resistance Analysis Following Combo DAA Resistance analysis detected RAVs in 90% of evaluable genotype 1 and 39% of genotype 3 HCV patients following DAA failure RAV, %Genotype 1 (n = 195)*Genotype 3 (n = 69) None1061 NS3 only14NA NS5A only4132 NS5B only42 NS3 + NS5A192 NS3 + NS5B1NA NS5A + NS5B † 53 NS3 + NS5A + NS5B6NA NA, not applicable. *14 patients excluded because of sequencing failure. † Includes 1 genotype 1b and 2 genotype 3 patients with S282T. Vermehren J, et al. EASL, Barcelona, April 13-17, 2016; PS103

26. Slide 26 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Efficacy of Retreatment with Current DAA Combos Retreatment Regimen After LDV/SOF or DCV + SOF Failure in Genotype 1 Interim SVR12, % (n/N) 12-wk SMV + SOF ± RBV (n = 6)100 (2/2) 24-wk SMV + SOF ± RBV (n = 11)100 (1/1) 12-wk PrOD ± RBV (n = 4)75 (3/4) 24-wk PrOD ± RBV (n = 1)NR Retreatment Regimen After SOF + RBV Failure in Genotype 3 Interim SVR12, % (n/N) 12-wk DCV + SOF + RBV (n = 3)100 (2/2) 24-wk DCV + SOF ± RBV (n = 10)100 (4/4) 24-wk LDV + SOF + RBV (n = 1)100 (1/1) Vermehren J, et al. EASL, Barcelona, April 13-17, 2016; PS103

27. Slide 27 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. ASTRAL-1, -2, -3, -4 Trials: Sofosbuvir/ Velpatasvir ± RBV in GT1-6 HCV  Multicenter, randomized phase III trials in Tx-naive and Tx-experienced pts ASTRAL-1 [1] : GT 1, 2, 4, 5, or 6 HCV (N = 740) Sofosbuvir/Velpatasvir (n = 624) Placebo QD (n = 116) 12 wks All pts followed for SVR12, primary endpoint ASTRAL-2 [2] : GT 2 HCV (N = 266) ASTRAL-3 [2] : GT 3 HCV (N = 552) Sofosbuvir/Velpatasvir (n = 134) Sofosbuvir + RBV (n = 132) Sofosbuvir/Velpatasvir (n = 277) Sofosbuvir + RBV (n = 275) Sofosbuvir/Velpatasvir (n = 90) Sofosbuvir/Velpatasvir + RBV (n = 87) Sofosbuvir/Velpatasvir (n = 90) 24 wks ASTRAL-4 [3] : GT1-6 HCV and CTP B cirrhosis (N = 267) 1. Feld JJ, et al. NEJM 2015;373:2599. 2. Foster GR, et al. NEJM 2015;373:2608. 3. Charlton MR, et al. AASLD 2015. Abstract LB-13. Sofosbuvir/velpatasvir 400/100 mg QD

28. Slide 28 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. ASTRAL-1: SVR12 With Sofosbuvir/ Velpatasvir in GT1, 2, 4, 5, 6 HCV Double-blind, placebo-controlled trial – Key baseline characteristics: cirrhosis 19%; Tx exp’d 32%; BL NS5A RAVs 42% No impact of cirrhosis, Tx experience, BL NS5A RAVs on SVR rates Feld JJ, et al. N Engl J Med. 2015;373:2599 HCV Genotype 99 98 99 100 97 100 41/ 41 34/ 35 116/ 116 104/ 104 117/ 118 206/ 210 618/ 624 100 80 60 40 20 0 n/N = SVR12 (%) All Pts1a1b2456 104/ 104

29. Slide 29 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. 100 ASTRAL-3 Open-Label Trial: SVR12, Safety With Sofosbuvir/Velpatasvir in GT3 HCV SVR12 rate numerically lower with vs without BL NS5A RAVs (88% vs 97%) Safety profile similar to ASTRAL-1 Foster GR, et al. N Engl J Med. 2015;373:2608. n/N = SVR12 (%) 80 60 40 20 0 264/277 221/275191/197163/187 73/ 80 55/ 83 200/ 206 176/ 204 64/ 71 45/ 71 95 80 63 90 97 87 91 66 86 All Pts NoYesNaive Experienced Cirrhosis P <.001 (superiority) SOF/VEL 12 wks SOF+RBV 24 wks Treatment History

30. Slide 30 of 30 From A Monto, MD, at San Francisco, CA: May 6, 2016, IAS-USA. Summary Fortunately, with cure rates of 92%+ for most patients, current therapies are often successful, limiting the need for retreatment Most patients who have not been cured by a DAA combination regimen will undergo RAV testing, which will inform the choice of their next HCV regimen HCV retreatment is not urgent for most patients; however, e.g. decompensated cirrhotics may be retreated sooner, as cure may stabilize their liver disease or even prevent the need for transplant Sofosbuvir/velpatasvir will have a special role in retreatment, due to its activity against many RAVs