1. CS-1 Lenalidomide Safety Assessment Study MDS-003, 002 Robert Knight, MD Vice President Clinical Research Oncology Celgene Corporation

2. CS-2 Safety in Del 5q Patients (120-Day Update) Study MDS-003

3. CS-3 Lenalidomide Exposure Del 5q (MDS-003)  148 received ≥ 1 dose of 10 mg  105/148 received ≥ 24 wk  Median exposure – 10 mg continuous (n = 103): 43.7 wk (0.4 - 68.0) – 10 mg cyclic (n = 45): 44.7 wk (2.0 - 69.9) 120-day SU T1.1.2

4. CS-4 DLTs  Grade 4 neutropenia  Platelet count < 30,000/µL  ≥ Grade 3 non-hematologic toxicity Lenalidomide Dose-Adjustment for DLT Del 5q (MDS-003) Dose reduction Starting dose level12 10 mg qd5 mg qd5 mg qod Most dose adjustments were for neutropenia and/or thrombocytopenia.

5. CS-5 Dosing by Week on Study Del 5q (MDS-003) § Highest frequency dose selected for each patient as their dose within each 4-wk period.

6. CS-6 Grade 3/4 Hematologic AEs ≥ 2% Del 5q (MDS-003) Patients, % N = 148 Grade 3Grade 4 Neutropenia16.940.5 Thrombocytopenia41.910.1 Febrile neutropenia4.70.7 Anemia3.44.1 Hemorrhagic events3.40.7 120-day SU T1.6.2

7. CS-7 Clinically Significant Cytopenia Del 5q (MDS 003) (12-31-04) Nadir platelet counts/µL N = 148 ≤ 10,000> 10,000 - ≤ 20,000 > 20,000 - ≤ 50,000 Patients, n (%)9 (6.8)16 (10.8)50 (33.7) Platelet transfusions, bleeding Clinically significant3 (2.0) 2 (1.3) Clinically insignificant6 (4.0)9 (6.8)4 (2.7)

8. CS-8 Grade 3/4 Hematologic AEs ≥ 2% Del 5q (MDS-003) Patients, % N = 148 Grade 3Grade 4 10 cont n = 103 10 cyclic n = 45 10 cont n = 103 10 cyclic n = 45 Neutropenia17.515.650.517.8 Thrombocytopenia44.735.66.817.8 Febrile neutropenia3.96.702.2 Anemia1.96.74.92.2 Hemorrhagic events1.96.702.2 120-day SU T1.6.2

9. CS-9 Median ANC/Platelets by Week for TI Responders Del 5q (MDS-003) 04812162024283236404448 0 1 2 3 4 ANC Platelets 0 100 200 300 400 BL/Scrn Wk ANC (10 9 /L) Platelets (10 9 /L)

10. CS-10 Median ANC/Platelets by Week for TI Non Responders Del 5q (MDS-003) 04812162024283236404448 0 1 2 3 4 ANC Platelets 0 100 200 300 400 BL/Scrn Wk ANC (10 9 /L) Platelets (10 9 /L)

11. CS-11 Grade 3/4 Non Hematologic AEs ≥ 3% Del 5q (MDS-003) Patients, % N = 148 Grade 3Grade 4 Fatigue6.10.0 Pneumonia6.12.0 Nausea4.70.0 Back pain4.10.7 Diarrhea4.10.0 Hypokalemia3.40.0 Pyrexia3.40.0 120-day SU T1.6.2

12. CS-12 Serious AEs > 2% Del 5q (MDS-003) Patients, % N = 148 All serious AEs Suspected drug related Pneumonia94 Neutropenia86 Pyrexia43 Febrile neutropenia43 Thrombocytopenia43 Dehydration40 Acute leukemia40 Anemia31 Congestive heart failure3< 1 Sepsis3< 1 Diarrhea30 Vomiting3< 1 120-day SU T1.6.2

13. CS-13 Patient Disposition Del 5q (MDS-003) Patients, n (%) 10 mg N = 148 Median time on study47 wks Discontinued study medication69 (47) Primary reason for discontinuations AE26 (18) Inadequate therapeutic effect26 (18) Patient withdrew consent3 (2) Death9 (6) Other5 (3) 120-day SU T1.2.2

14. CS-14 AEs Leading to Discontinuation Del 5q (MDS-003) (n/N = 26/148)  Reasons for discontinuation – Thrombocytopenia 8 (5.4%) – Neutropenia 4 (2.7%) – Rash 4 (2.7%) – Pneumonia 2 (1.4%)  All other AEs leading to discontinuations were reported in 1 patient each 120-day SU T1.7.2

15. CS-15 Deaths on Study or ≤ 30 Days After Drug Termination Del 5q (MDS-003) Patients, n (%) N = 148 Deaths11 (7) Suspected as drug related3 (2) Neutropenia/pneumonia1 Neutropenia/Klebsiella sepsis1 Pancytopenia/sepsis1 Not suspected8 (5) CHF3 Ischemic colitis/CHF/multiorgan failure1 Sudden death1 Intestinal perforation at colonoscopy1 Acute leukemia1 Traumatic SAH/subdural hematoma1 120-day SU T20.1

16. CS-16 Safety in Non-Del 5q Patients (12-31-04) Study MDS-002

17. CS-17 Grade 3/4 AEs > 3% Non Del 5q (MDS-002) Patients, % N = 215 Grade 3Grade 4 Thrombocytopenia19.54.7 Anemia5.61.9 Neutropenia6.521.9 Atrial fibrillation4.20.5 Cardiac failure congestive4.20.0 Diarrhea3.30.0 Fatigue3.70.0 Pneumonia4.70.0 Rash4.20.0 120-day SU T1.6.2

18. CS-18 MDS On-Study Deaths MDS-001, 002, 003 (Pooled)  n/N = 26/408 (6%) – 5 (1%) suspected as drug related  Median age (min, max) at time of death – 80 (62, 93)  Time to death from MDS diagnosis – Median, yr (range): 2.8 (1 - 12) 18DV per client

19. CS-19 Safety Conclusions  Favorable safety profile  Neutropenia/thrombocytopenia – Most common AEs – Manageable with dose interruption/reduction – Frequency in non del 5q ~ half of del 5q – Consistent with putative mechanism of action  Non hematologic AEs were mild and infrequent

20. CS-20 Dosing Regimen Conclusions  MDS-001 established 10 mg starting dose  MDS-002 (non del 5q) and MDS-003 (del 5q) used a starting dose of 10 mg, with dose adjustments based on clinical and laboratory findings  Durable TI responses, in a high proportion of del 5q patients, with readily managed AEs