1. Adriano Venditti Ematologia Universita’ Tor Vergata, Roma
L’anticorpo anti-CD33 nella Leucemia Mieloide Acuta
Adriano Venditti
Ematologia Universita’ Tor Vergata, Roma

2. Targeting Leukemia-Associated Ag
CD45
131I-BC8
99Tc-YTH 24.5
GM-CSFr
DTGM
CD66
188Re-antiCD66
99Tc-BW 250/183
VEGF
Bevacizumab
CD44, IL3, CLL1
LSC therapy

3. Targeting Leukemia-Associated Ag
CD33
Ab-CD33 Ag complex rapidly internalizes and translocates into lysosomes
Expressed in 90% of AMLs
Down-regulated with maturation of myeloid lineage
Not expressed on primitive HSCs and non-hematopoietic tissues
> 10,000 copies/cell in AML

4. The most beneficial effects are seen in patients
HuM195 (Lintuzumab)
Recombinant humanized version of the mouse MoAb M195 directed against CD33
It consists of a human IgG1 framework that contains
a human constant region
a murine CDR
Same specificity, immunoreactivity and internalization as the parent mouse M195
Higher avidity
Ability to mediate ADCC against leukemia targets in vitro
The most beneficial effects are seen in patients
with low leukemia burden

5. Gemtuzumab Ozogamicin
Anti-CD33-Calicheamicin immunoconjugate
IgG4 anti-CD33
Linker OH
CH3 CH2
OCH3 O Me NH
NHN S H HO N
CH3 HN I
Slide 11: Gemtuzumab Ozogamicin
Gemtuzumab ozogamicin (GO) is an antibody-targeted chemotherapy. The antibody portion is a recombinant, humanized murine monoclonal antibody that recognizes CD33.
CD33 is expressed on 90% of blasts from patients with AML and is absent from normal hematopoietic stem cells.
The antiCD33 antibody is linked to a calicheamicin derivative, which is a highly potent cytotoxic antibiotic.
Reference
Mylotarg® Prescribing Information. Wyeth Laboratories. Philadelphia, PA; 2002.
Calicheamicin derivative
DNA minor groove
binding
Mylotarg® Prescribing Information. Wyeth Laboratories. Philadelphia, PA; 2002.

6. Areas of investigation in AML
Frontline therapy
Combination therapy (simultaneous/sequential)
Single agent (elderly unfit)
Consolidation
Single agent & combination therapy
Maintenance
Single agent (AML, APL)
Relapsed/refractory
Single agent & combination therapy (AML, APL)
Transplant
conditioning
in vitro purging

7. Phase II trials in AML (1st relapse)
277 patients
Median age 61 (20-87)
9 mg/m2 2-hr infusion, day 1 and 15
ORR 26%;
Median OS 4.9 mos
Median OS for CR/CRp pts 12.5 mos
Incidence of VOD/SOS 5.3%

8. EORTC/GIMEMA AML-15B Age >75 + PS 0-2 Age <76 + PS 2
“Frail” patients
Age >75 + PS 0-2
Age <76 + PS 2
GO x 2
Response Assessment

9. AML-15B Induction Results
No. patients 40
CR 4 (10%)
CRp 3 (7.5%)
Induction death 7 (17.5%)
Early death 5
Hypopl death 2
VOD 1 (2.5%)
CR+CRp 17.5% (95% CI, 8.7% %)

10. AML-19 Phase II: outline R Day 36 CR/CRp/PR/NC CR/CRp/PR/NC
Control Arm
Supportive care
Regimen 1
GO 6 mg/m2 d 1
GO 3 mg/m2 d 8
Regimen 2
GO 3 mg/m2
d 1, 3, 5
Day 36
CR/CRp/PR/NC
CR/CRp/PR/NC
Continuation
GO 2 mg/m2 every 4 weeks x 8
Day 50

11. AML-19 Phase III: outlineR
Control Arm
Supportive care
Best GO regimen
GO 6 mg/m2 d 1
GO 3 mg/m2 d 8
CR/CRp/PR/NC
Day 36
Continuation
GO 2 mg/m2 every 4 weeks x 8
Day 50

12. EORTC/GIMEMA AML-15A “Fit” patients Age 61-75 + PS 0-1 GO x 2
Response Assessment
MICE x 2

13. AML-15A Induction Results
Overall Response
Pts
CR (35.1%)
CRp 11 (19.3%)
ID (14.1%)
VOD (8.8%)
CR+CRp 54.4%
(95% CI, 41.6% %)
Response to GO
Pts 57
CR (22.8%)
CRp (12.3%)
CR+CRp 35.1%
(95% CI, 24% %)

14. R AML-17: outline Induction Consolidation GO+MICE GO+m-ICE x 2 MICE
GO/induct 6 mg/m2 day 1, 15
GO/consol 3 mg/m2 day 0

15. To compare three induction schedules (ADE, DA and FLAG-Ida)
MRC AML 15 Schema
DA 3+10
± GO
FLAG-Ida
DA 3+8
MACE
MidAc
AraC 3g/m2
Ara-C
3g/m2
AraC 1.0g/m2
ADE
8+3+5
Ara-C 1.5g/m2 ± GO
Ara-C 1.5g/m2
Stop therapy
Course 1
Course 2
Course 3
Course 4 R
Course 5
ADE ± GO
RISK
ASSESSMENT
To compare three induction schedules (ADE, DA and FLAG-Ida)
To assess the value of GO during induction when used in combination with ADE or DA or FLAG-Ida
Burnett AK et al. ASH Abstract 13

16. MRC AML 15 trial: outcomes (1113 patients)
Overall CR rate 86%
Similar rates of postinduction CR with gemtuzumab + induction vs induction chemotherapy alone
85% vs 87% (p = 0.3)
Similar rates of mortality
7% vs 7% (p = 0.6)
Similar rates of resistant disease
8% vs 6% (p = 0.3)
Treatment generally tolerable with similar rates of adverse events in each arm
CR, complete remission; DFS, disease-free survival
In this preliminary analysis, overall survival was not different between arms. Complete remission rates were also similar, at 84% with gemtuzumab during induction and 86% without gemtuzumab. There were no differences in early mortality with vs without gemtuzumab, at 8% and 7%, respectively. Resistance disease rates were also similar between groups. Gemtuzumab did significantly increase disease-free survival in patients with favorable or intermediate cytogenetics (P < .02) but without improving overall survival, at least during this early analysis. Treatment was well tolerated, and the investigators observed similar adverse effects in each arm. There was no significant difference in the frequency of grade 3 or 4 hepatic toxicity, indicating that this is a safe regimen to use during induction therapy. Overall, this study suggests that the addition of gemtuzumab during induction chemotherapy may benefit patients with favorable or intermediate cytogenetics.
Burnett AK, et al. ASH Abstract 13.

19. HOVON-SAKK AML-43 Protocol AML/RAEB-t
ARA-c 1 gr/m2 x 12 R
ARA-c 200 mg/m2 x 7
DNR 45 mg/m2 x 3
DNR 90 mg/m2 x 3
CYCLE 1
CYCLE 2
Post-Remission
No therapy
Mylotarg 6 mg/m2 q 4 wks x 3

20. SWOG - 106 Trial ARA-c + DNR + No therapy Mylotarg 6 mg/m2 d 4 High
Dose
ARA-c
No therapy
Mylotarg x 3

21. ECOG Protocol E1900: Dose Intensification in Induction and GO pre AuSCT
AlloSCT CR
Cytarabine
DNR 45 mg/m2 x 3
DNR 90 mg/m2 x 3
HiDAC x 2 PSCH after 2 course
Mylotarg
6 mg/m2
AuSCT
High-risk

22. Molecular remission in: 9 of 11 pts tested after 2 doses,
LOW-DOSE (6mg/m2) GO FOR MOLECULARLY RECURRENT/PERSISTENT APL
Dose 1 +
Dose 2
PCR (day 43)
Molecular remission in:
9 of 11 pts tested after 2 doses,
13 of 13 tested after the third dose
PCR+ve
PCR-ve
Dose 3 and successive
doses until PCR-negativity
(max 3 further doses)
Dose 3
( final dose)
Lo Coco et al. Blood 2004

23. VOD (SOS) Incidence 0.9% among pts not undergoing HSCT
19% among pts with HSCT prior GO
17% amomg pts with HSCT after GO
In observational studies rates of VOD/SOS between 15-40% if SCT performed within 3 mos of GO administration
FDA Prospective Observational Registry (60 centers) identified VOD/SOS rates of
14% with SCT
9% without SCT

24. VOD (SOS) Pathophysiological Hypothesis
Direct injury of CD33+ Kupfer cells
Circulating tumor load
Tumor load in the liver
Circulating soluble CD33
Defective secretion of gluthionyl calicheamicin, leading to activation of stellate cells

25. Conclusive remarks
GO as a single agent has limited activity in overt AML
Elimination of MRD, especially in APL?
Doses  6 mg/m2 equally effective than 9 mg/mg2
Integration of GO with standard CHT under investigation
Better quality of remission in selected categories of pts?
Combo therapy of GO with other MoAb
GO-related VOD/SOS prevention?