1. © 2014 Direct One Communications, Inc. All rights reserved. 1 Belatacept: An Update of Ongoing Clinical Trials Michael D. Rizzari, MD University of Wisconsin–Madison School of Medicine and Public Health, Madison, Wisconsin A REPORT FROM THE 2014 WORLD TRANSPLANT CONGRESS

2. © 2014 Direct One Communications, Inc. All rights reserved. 2 Overview of Belatacept Belatacept has been approved by the FDA for prophylaxis of organ rejection in adults receiving a kidney transplant; it is administered via monthly infusion in combination with basiliximab induction, mycophenolate mofetil (MMF), and corticosteroids. Because its effects are believed to be highly specific for the B7-CD28 pathway, belatacept ultimately may serve as a therapeutic alternative to avoid the long-term toxicity of calcineurin inhibitors (CNIs). However, belatacept should be used only in patients who are Epstein-Barr virus (EBV) seropositive to minimize the risk of precipitating post-transplant lymphoproliferative disorder (PTLD). Chopra B, Sureshkumar K. Expert Opin Biol Ther. 2014;14:563; Sayegh MH, Turka LA. N Engl J Med. 1998;338:1813; Vincenti F et al. N Engl J Med. 2005;353:770; McAdam AJ et al. Immunol Rev. 1998;165:231

3. © 2014 Direct One Communications, Inc. All rights reserved. 3 Overview of Belatacept continued Although belatacept therapy has been associated with increased rates of PTLD and early acute rejection, its use in kidney-transplant recipients may lead to fewer late acute-rejection episodes. The cardiovascular and metabolic profiles of this drug and its impact on renal function appear to be superior to those of cyclosporine-based regimens. Rates of patient and graft survival appear to be comparable between belatacept and cyclosporine. Use of this drug in liver-transplant recipients is controversial because some early studies showed an increase in the risk of graft loss and death. Vincenti F et al. Am J Transplant. 2010;10:535; Durrbach A et al. Am J Transplant. 2010;10:547; Vincenti F et al. Am J Transplant. 2012;12:210; Pestana JO et al. Am J Transplant. 2012;12:630; Rostaing L et al. Am J Transplant. 2013; 13: 2875; Charpentier B et al. Am J Transplant. 2013;13:2884

4. © 2014 Direct One Communications, Inc. All rights reserved. 4 Mechanism of Action Belatacept is a fusion protein that acts as an antagonist of the B7 ligands (CD80 and CD86) present on antigen-presenting cells. These ligands interact with CD28 on naïve T cells and are crucial to the costimulation pathway involved in the activation and proliferation of effector T cells. Blockade of this pathway may inhibit cytokine upregulation, apoptosis, B-cell antibody production, and T-cell differentiation. Chopra B, Sureshkumar K. Expert Opin Biol Ther. 2014;14:563; Vincenti F et al. N Engl J Med. 2005;353:770

5. © 2014 Direct One Communications, Inc. All rights reserved. 5 Results of Pivotal Clinical Trials: BENEFIT and BENEFIT-EXT The phase 3 BENEFIT trial studied transplant recipients who received a kidney from a living or standard-criteria deceased donor. The phase 3 BENEFIT-EXT trial studied transplant recipients who received a kidney from an extended- criteria deceased donor. In both studies, patients received corticosteroids and basiliximab for induction therapy intraoperatively and MMF and tapering doses of the corticosteroid postoperatively. Vincenti F et al. Am J Transplant. 2010;10:535; Durrbach A et al. Am J Transplant. 2010;10:547; Vincenti F et al. Am J Transplant. 2012;12:210; Pestana JO et al. Am J Transplant. 2012;12:630; Rostaing L et al. Am J Transplant. 2013; 13: 2875; Charpentier B et al. Am J Transplant. 2013;13:2884

6. © 2014 Direct One Communications, Inc. All rights reserved. 6 Results of Pivotal Clinical Trials: BENEFIT and BENEFIT-EXT continued Patients were randomized 1:1:1 to receive cyclosporine (100–250 ng/mL) or a more-intensive (MI) or less- intensive (LI) regimen of belatacept for 6 months, followed by 5 mg/kg of belatacept every 4 weeks. Rostaing L et al. Am J Transplant. 2013; 13: 2875

7. © 2014 Direct One Communications, Inc. All rights reserved. 7 Results of Pivotal Clinical Trials: BENEFIT and BENEFIT-EXT continued In both studies, the mean calculated glomerular filtration rate (GFR) was significantly higher in both belatacept treatment groups when compared with the GFR in cyclosporine-treated patients at 3 years and 5 years after transplantation. Patients receiving belatacept had better control of their blood pressure, needed fewer antihypertensive medications, and had significantly better metabolic profiles than patients who received cyclosporine. Vincenti F et al. Am J Transplant. 2012;12:210; Pestana JO et al. Am J Transplant. 2012;12:630; Rostaing L et al. Am J Transplant. 2013; 13: 2875; Charpentier B et al. Am J Transplant. 2013;13:2884

8. © 2014 Direct One Communications, Inc. All rights reserved. 8 Results of Pivotal Clinical Trials: BENEFIT and BENEFIT-EXT continued Renal function at 3 years was superior in patients who had received belatacept compared with those who had been treated with cyclosporine. All three groups of patients showed similar rates of patient and graft survival and acute graft rejection. No significant differences in the frequency of serious adverse events or late onset of PTLD were detected across the three treatment groups; however, patients who received belatacept had a higher rate of early- onset PTLD, especially among those were EBV seronegative prior to transplantation. Vincenti F et al. Am J Transplant. 2012;12:210; Pestana JO et al. Am J Transplant. 2012;12:630; Vincenti F et al. J Am Soc Nephrol. 2010;21:1587; Griny ó J et al. Transplantation. 2010; 90:1521

9. © 2014 Direct One Communications, Inc. All rights reserved. 9 Long-Term Safety of Belatacept A detailed vascular function analysis of 23 belatacept recipients and 23 cyclosporine recipients over a median of 81 months (~ 7 years) found no difference between the two groups in systolic or diastolic blood pressure or pulse wave velocity; however, central aortic augmentation pressure was significantly higher in the cyclosporine group. In a study of 10-year outcomes of patients who were randomized to the belatacept arm of a phase 2 trial, 46% of the remaining 44 patients missed a single infusion or less, 84% had serious adverse events (including 36% with significant infections and 23% with malignancies), and none developed PTLD. Siebert F et al. 2014 World Transplant Congress, Abstract A200; Charpentier B et al. 2014 World Transplant Congress, Abstract 2164.

10. © 2014 Direct One Communications, Inc. All rights reserved. 10 Long-Term Safety of Belatacept continued Changes in mean calculated glomerular filtration rate (cGFR) over 10 years in a long-term extension study of the 44 remaining kidney- transplant recipients who were originally randomized to treatment with belatacept (5 mg/kg) every 4 or 8 weeks Charpentier B et al. 2014 World Transplant Congress, Abstract 2164.

11. © 2014 Direct One Communications, Inc. All rights reserved. 11 Donor-Specific Antibody Formation In a 5-year study of donor-specific antibody (DSA) formation in patients enrolled in the BENEFIT and BENEFIT-EXT trials, lower rates of de novo DSA development were seen in patients who had been randomized to belatacept immunosuppression than among those treated with cyclosporine. Bray R et al. 2014 World Transplant Congress, Abstract 2163.

12. © 2014 Direct One Communications, Inc. All rights reserved. 12 Belatacept vs Tacrolimus Live- and deceased-donor kidney-transplant recipients were randomized 1:1:1 to treatment with belatacept and MMF, belatacept and sirolimus, or tacrolimus and MMF with steroid avoidance. At 12 months, the rate of graft survival was higher in the tacrolimus-MMF group (100%) than among the belatacept-MMF (91%) and belatacept-sirolimus (92%) groups. However, the GFR was 8–10 mL/min/1.73 m 2 higher in both belatacept treatment groups at month 12 than in the tacrolimus-MMF group. Ferguson R et al. Am J Transplant. 2011;11:66

13. © 2014 Direct One Communications, Inc. All rights reserved. 13 Belatacept vs Tacrolimus continued At 4 years, patients in the belatacept-MMF and belatacept-sirolimus arms had higher mean calculated GFRs than did those in the tacrolimus- MMF arm (59.6, 72.2, and 55.7 mL/min/1.73 m 2, respectively) Woodle E et al. 2014 World Transplant Congress, Abstract 2157

14. © 2014 Direct One Communications, Inc. All rights reserved. 14 Belatacept vs Tacrolimus continued There was no difference among the three groups in the proportion of patients alive with functioning grafts 4 years after randomization. The safety profiles of all three drug regimens were similar. The rates of serious adverse events also were similar across all three arms, and there were no differences among the three regimens in rates of new-onset diabetes, dyslipidemia, or hypertension. However, the numbers of patients who participated in this study were small. Woodle E et al. 2014 World Transplant Congress, Abstract 2157; Griny ó J et al. 2014 World Transplant Congress, Abstract 2162

15. © 2014 Direct One Communications, Inc. All rights reserved. 15 Conversion from CNIs to Belatacept In a study of 18 patients who were switched to belatacept after 6 weeks to 12 years of maintenance immunosuppression with CNIs, 15 remained on belatacept for 1–18 months of follow-up. Four of the 15 patients developed cytomegalovirus viremia after the conversion; none of the patients developed BK viremia or de novo DSAs. One episode of acute graft rejection occurred 3 months after the conversion. The average serum creatinine concentration fell from 2.6 mg/dL at the time of conversion to 2.0 mg/dL. Villicana R et al. 2014 World Transplant Congress, Abstract A199

16. © 2014 Direct One Communications, Inc. All rights reserved. 16 Conversion from CNIs to Belatacept continued Eleven patients converted to belatacept after a period of delayed graft function ranging from 18 to 74 days (mean, 45 days) were compared with a historic control group of 22 patients who continued receiving tacrolimus immunosuppression. Mean time to biopsy for the belatacept group was significantly later than it was for the tacrolimus group. Mean number of dialysis treatments and mean calculated GFR at 3 and 6 months post transplant were similar between the two groups, as were the rates of acute rejection and infection. Wojciechowski D et al. 2014 World Transplant Congress, Abstract A201

17. © 2014 Direct One Communications, Inc. All rights reserved. 17 Conversion from CNIs to Belatacept continued In a key study, 173 patients receiving a CNI-based regimen were randomized to switch to belatacept (n = 84) or remain on their CNI regimen (n = 89) within 6–36 months post transplant. At 1 year follow-up, the mean calculated GFR and mean increase in calculated GFR were both higher in the group that had been converted to belatacept. However, more episodes of acute graft rejection, but no graft losses, occurred in the belatacept arm. Safety profiles were similar between the group that had converted to belatacept and the group that had remained on CNI therapy. Rostaing L et al. Clin J Am Soc Nephrol. 2011;6:430

18. © 2014 Direct One Communications, Inc. All rights reserved. 18 Belatacept Monotherapy Twenty live-donor kidney-transplant recipients receiving alemtuzumab induction and maintenance immunosuppression with belatacept and sirolimus were randomized 1:1 to receive unfractionated donor bone marrow or continue on their present regimen. After 1 year, all patients were allowed to wean off their sirolimus regimen. Ten patients elected to wean from sirolimus. Graft function was similar at 12 and 36 months between patients who remained on belatacept plus sirolimus and those who received belatacept alone. Kirk A et al. 2014 World Transplant Congress, Abstract 712

19. © 2014 Direct One Communications, Inc. All rights reserved. 19 Belatacept Monotherapy continued No graft rejections were observed in either the group who remained on belatacept plus sirolimus or the group that elected to continue on belatacept alone. Donor-specific hyporesponsiveness was noted in 16 of 19 recipients, based upon serial in vitro measurements of intracellular cytokine production. An additional 16-patient cohort was sampled, this time using eight deceased-donor kidney-transplant recipients; this second cohort achieved similar results, with excellent graft function at latest follow- up, and all 16 patients remained rejection-free. Kirk A et al. 2014 World Transplant Congress, Abstract 712

20. © 2014 Direct One Communications, Inc. All rights reserved. 20 Improving the Efficacy of Belatacept Nineteen renal-transplant recipients maintained on belatacept and MMF following rabbit antithymocyte globulin induction and converted to belatacept plus everolimus, with or without corticosteroids, 1 month post transplant were compared with 38 patients who were maintained on tacrolimus plus MMF, with or without corticosteroids, following basiliximab induction. The rate of delayed graft function was higher in the belatacept group, but the mean calculated GFR and rates of acute rejection and infection were similar between the two groups at 1, 3, and 6 months. Wojciechowski D et al. 2014 World Transplant Congress, Abstract A197

21. © 2014 Direct One Communications, Inc. All rights reserved. 21 Conclusion Belatacept is a promising new immunosuppressant approved for maintenance therapy in adult EBV- seropositive kidney transplant recipients. Some concerns regarding early acute rejection and PTLD exist, but graft survival does not seem to be affected. A main benefit of belatacept is the improvement in calculated GFR when compared with the use of other maintenance immunosuppression regimens. More clinical trials are needed to assess the efficacy and safety of long-term belatacept therapy in combination with other immunosuppressive agents.