Concentration-Controlled Trials and Therapeutic Drug Monitoring

1. RAPAMUNE® Concentration-Controlled Trials and Therapeutic Drug Monitoring James Zimmerman, PhD Senior Director, Clinical PharmacokineticsClinical Research and DevelopmentWyeth-Ayerst Research TM

2. Key Messages in This Presentation • There is sufficient understanding of sirolimus PK to apply therapeutic drug monitoring (TDM) in patients • A robust and reliable sirolimus assay is available • The concentration range for sirolimus TDM has been defined and is effective • Data are available to show that physicians can use TDM in renal allograft patients

3. Currently ApprovedRAPAMUNE Regimen • The currently approved RAPAMUNE regimen is a fixed-dose regimen (RAPA administered 4 hours after cyclosporine) • Fixed-dose administration is recommended for most patients during co-administration with cyclosporine

4. Concentration-ControlledRAPAMUNE Administration • Recommended when administered with cyclosporine (RAPA administered 4 hours after cyclosporine) • in pediatric patients • in hepatic impairment • during administration with strong inducers/inhibitors of CYP3A and P-gp • after marked changes in cyclosporine doses • Required when administered without cyclosporine • Method of dose administration for the proposed indication (RAPA administered 4 hours after cyclosporine)

5. Two Sirolimus Assay Methods Were Used to Measure Trough Levels • Sirolimus concentrations in this presentation • are expressed in terms of the immunoassay

6. Sirolimus Dose-Proportionality and aLinear Cmin vs AUC Relationship Simplify Concentration- Controlled Dosing

7. The Sirolimus Cmin vsAUC Relationship is Linear (Study 301, RAPA + Cyclosporine)

8. Sirolimus Pharmacokinetics Influences the Implementation of Concentration-Controlled Dosing

9. Four Studies Contributed Data for RAPAMUNE Concentration-Controlled Regimens Time RAPAMUNE Post-transplant Studies Study Type Formulation £ 310 Pivotal Tablet 1 year 212 Supportive Solution 207, 210 Early Studies Solution (RAPA vs CsA)

10. Sirolimus Target Concentration Ranges after Cyclosporine Withdrawal in Studies 212 and 310 • Set prospectively based on results from Phase II Studies 207 and 210 • For sample analysis by Immunoassay, the ranges were • 10 - 20 ng/mL (Study 212) • 20 - 30 ng/mL (Study 310) • The adequacy of the prospective target ranges were supported by • Efficacy results • Mean sirolimus trough levels (18 vs 23 ng/mL)

11. Outcomes of Sirolimus Concentration Control Among Studies (RAPA Group)

12. Sirolimus and Cyclosporine Trough Levels for Study 310 (RAPA Group)

13. Comments Regarding the Rate of Cyclosporine Withdrawal in Study 310 • Overall, the investigators were successful in this first RAPAMUNE trial that required the simultaneous adjustment of 2 drugs • Cyclosporine was eliminated in 50% of patients by Week 6 after randomization • The ability to achieve the sirolimus target range will improve as physicians gain more experience with cyclosporine withdrawal

14. A Mean RAPAMUNE Dose of 8 mg/day Maintained Sirolimus in the Target Range for Study 310 23.3 8.4

15. Implementation of Sirolimus TDM • Frequency of blood sampling for sirolimus assays after randomization in Study 310 • Number of days required to reach the target range in Study 310 • Number of dose changes required to reach the target range in Study 310 • Sirolimus TDM range • Availability of sirolimus assays

16. Frequency of Blood Sampling For SirolimusAssays After the Start of Cyclosporine Withdrawal(Study 310)

17. Number of Days and Dose Changes Required to Achieve the Target Range in Study 310

18. Sirolimus TDM Range • The sirolimus TDM range was determinedbased on • Distribution analyses of sirolimus trough levels among non-rejectors and rejectors • Clinical outcomes for Studies 212 and 310

19. Distributions of Average Sirolimus Trough Levels Among Non-Rejectors in Studies 310 and 212 (RAPAMUNE Groups)

20. Distributions of Sirolimus Trough Levels Among Rejectors in Studies 310 and 212(RAPAMUNE Groups)

21. Sirolimus TDM Considerably ReducedIntersubject Variability in Study 310 Compared to a Predicted 8-mg Fixed-dose Regimen

22. RecommendedSirolimus TDM Range • A sirolimus TDM range of 15 to 25 ng/mL (Immunoassay) is recommended based on • The distributions of sirolimus trough levels among non-rejectors and rejectors in Studies 310 and 212 • The very similar clinical outcomes in Studies 310 and 212 with respect to graft survival, patient survival, and improved renal function within the RAPAMUNE treatment groups

23. 23 Bioanalytical Laboratories Measure Sirolimus Concentrations

24. Guidance In Using Sirolimus TDM • Guidance will be provided to physicians with respect to • Algorithms for estimating both a new maintenance dose and a new loading dose • Maximum recommended dose per day • Timing of blood draws for dose adjustments • Action guidelines based on assay results • Limitations of TDM

25. Conclusions (I) • Experience with sirolimus TDM (without concurrent cyclosporine administration) has been obtained in 4 clinical trials during 1 year post-transplant among 347 patients • Efficacy outcomes in the TDM groups were equivalent to their respective fixed dose groups • Pharmacokinetic data and clinical outcomes for Studies 310 and 212 defined the range of sirolimus trough concentrations for TDM • The results show that TDM can guide the safe and effective use of sirolimus

26. Conclusions (II) • TDM without cyclosporine co-administration (proposed indication) • Recommended sirolimus TDM range • Immunoassay: 15 to 25 ng/mL • Chromatographic assay: 12 to 20 ng/mL